Released June 04, 2024 07:19 EST
2024, Fact Sheet 2024-3008
Hana R. Thurman, Nicholas M. Enwright, Michael J. Osland, Davina L. Passeri, Richard H. Day, Bethanie M. Simons
National parks and preserves in the South Atlantic-Gulf Region contain valuable coastal habitats such as tidal wetlands and mangrove forests, as well as irreplaceable historic buildings and archeological sites located in low-lying areas. These natural and cultural resources are vulnerable to accelerated sea-level rise and escalating high tide flooding events. Through a Natural Resources Preservation Program-funded project during 2021–23, the U.S. Geological Survey, in collaboration with the National Park Service, estimated the probability of inundation at Timucuan Ecological and Historic Preserve, Florida, and several other parks under various sea-level rise scenarios and contemporary high tide flooding thresholds. The maps produced for this effort can be used to assess potential habitat change and explore how infrastructure and cultural resources within the park may be exposed to future flooding-related hazards.
Released June 03, 2024 10:45 EST
2024, Fact Sheet 2024-3003
Katherine Walton-Day, Benjamin J. Siebers, Jo Ellen Hinck, Kate M. Campbell, Marie-Noële Croteau
The Grand Canyon region is an important natural, cultural, and archeological resource known worldwide. The region contains uranium resources that could be used to generate electricity. The U.S. Geological Survey (USGS), in cooperation with the National Park Service, Bureau of Land Management, and U.S. Department of Agriculture Forest Service, is conducting studies to answer questions about the environmental effects of mining uranium and other associated elements in the region.
Released May 31, 2024 14:50 EST
2024, Fact Sheet 2024-3020
Ronald Busciolano, John P. Masterson, Robert F. Breault
Freshwater is a vital natural resource. Although New York is a water-rich State, the wise and economical use of water resources is needed to ensure that there is enough water of adequate quality for both human and ecological needs—both for today and for tomorrow. Nowhere in New York is this more evident than in Nassau and Suffolk Counties on Long Island, where the public water supply is obtained from the sole-source aquifers located directly beneath the nearly 3 million people who live there. In 2023, in eastern Long Island’s Suffolk County, groundwater was pumped from these aquifers by more than 1,100 public water-supply wells to meet the needs of about 1.5 million people.
Released May 31, 2024 12:14 EST
2024, Fact Sheet 2024-3019
Adam Sepulveda, Cheryl Morrison, Maggie Hunter, Mona Khalil
The U.S. Geological Survey (USGS) researches the biological diversity and distribution of species to support management, conservation, and resource use decisions. USGS scientists advance detection and monitoring technologies to assess changes in fish and wildlife populations, biodiversity, and the health of ecosystems. The United States is planning to install 30 gigawatts of offshore marine and wind energy by 2030. However, the effects on fish and wildlife and their habitats are not well understood. The USGS is a leader in the field of eDNA technologies and has helped advance robotic eDNA samplers, has extensive experience working in the offshore environment, and has developed novel and actionable statistical methods and standards for eDNA monitoring applications. This fact sheet presents key eDNA research and development advances needed for realizing the potential of eDNA biodiversity monitoring tools in the marine environment and applying eDNA monitoring to offshore renewable energy development. New and cost-effective tools for measuring changes in biodiversity in response to offshore renewable energy development can help to inform natural resource management and project planning and permitting decisions.
Released May 31, 2024 06:51 EST
2024, PeerJ (12)
Robert S. Cornman
Background
Previous work found that numerous genes positively selected within the hoary bat (Lasiurus cinereus) lineage are physically clustered in regions of conserved synteny. Here I further validate and expand on those finding utilizing an updatedL. cinereusgenome assembly and additional bat species as well as other tetrapod outgroups.
Methods
A chromosome-level assembly was generated by chromatin-contact mapping and made available by DNAZoo (www.dnazoo.org). The genomic organization of orthologous genes was extracted from annotation data for multiple additional bat species as well as other tetrapod clades for which chromosome-level assemblies were available from the National Center for Biotechnology Information (NCBI). Tests of branch-specific positive selection were performed forL. cinereususing PAML as well as with the HyPhy package for comparison.
Results
Twelve genes exhibiting significant diversifying selection in theL. cinereuslineage were clustered within a 12-Mb genomic window; one of these (Trpc4) also exhibited diversifying selection in bats generally. Ten of the 12 genes are landmarks of two distinct blocks of ancient synteny that are not linked in other tetrapod clades. Bats are further distinguished by frequent structural rearrangements within these synteny blocks, which are rarely observed in other Tetrapoda. Patterns of gene order and orientation among bat taxa are incompatible with phylogeny as presently understood, implying parallel evolution or subsequent reversals. Inferences of positive selection were found to be robust to alternative phylogenetic topologies as well as a strong shift in background nucleotide composition in some taxa.
Discussion
This study confirms and further localizes a genomic hotspot of protein-coding divergence in the hoary bat, one that also exhibits an increased tempo of structural change in bats compared with other mammals. Most genes in the two synteny blocks have elevated expression in brain tissue in humans and model organisms, and genetic studies implicate the selected genes in cranial and neurological development, among other functions.
Released May 31, 2024 06:49 EST
2024, Conference Paper, Proceedings of the 2024 SIAM International Conference on Data Mining (SDM)
Rahul Ghosh, Wallace (Andy) Mcaliley, Arvind Renganathan, Michael Steinbach, Christopher Duffy, Vipin Kumar
Many environmental systems (e.g., hydrology basins) can be modeled as entity whose response (e.g., streamflow) depends on drivers (e.g., weather) conditioned on their characteristics (e.g., soil properties). We introduce Entity-aware Conditional Variational Inference (EA-CVI), a novel probabilistic inverse modeling approach, to deduce entity characteristics from observed driver-response data. EA-CVI infers probabilistic latent representations that can accurately predict response for diverse entities, particularly in out-of-sample few-shot settings. EA-CVI's latent embeddings encapsulate diverse entity characteristics within compact, low-dimensional representations. EA-CVI proficiently identifies dominant modes of variation in responses and offers the opportunity to infer a physical interpretation of the underlying attributes that shape these responses. EA-CVI can also generate new data samples by sampling from the learned distribution, making it useful in zero-shot scenarios. EA-CVI addresses the need for uncertainty estimation, particularly during extreme events, rendering it essential for data-driven decision-making in real-world applications. Extensive evaluations on a renowned hydrology benchmark dataset, CAMELS-GB, validate EA-CVI's abilities.
Released May 30, 2024 20:00 EST
2024, Scientific Investigations Report 2024-5028
Leon J. Kauffman
Groundwater flow between 2014 through 2040 was simulated in the New Jersey Coastal Plain based on three withdrawal scenarios. Two of the scenarios were based on projected population trends and the assumption of water conservation; the nominal water-loss scenario projected a status quo in the efficiency of water loss in the delivery systems whereas the optimal water-loss scenario projected a better water-loss efficiency resulting in less withdrawals. The third scenario assumes that all wells will withdraw water at their full allocation level which is generally much more than reported withdrawals in 2013 or projected under the other two scenarios.
Maps and summaries of heads and drawdowns are presented for nine confined aquifers. All the aquifers have areas with heads below sea level by 2040. Of the three scenarios, the drawdowns are most extreme in the full allocation scenarios; there are large areas of head decline greater than 20 feet in 5 of the 9 confined aquifers. The exceptions are the Vincentown aquifer, despite some areas of large drawdown in the vicinity of wells, and the three Potomac-Raritan-Magothy (PRM) aquifers where withdrawals are regulated by Critical Area restrictions. The nominal and optimal water-loss scenarios have some areas of head declines; most are less than 15 feet. The simulation of these scenarios shows some extensive areas of head recovery as well—especially in the aquifers that are regulated by the Critical Area restrictions.
Budgets of inflow and outflow components were calculated for 44 hydrologic budget areas (HBAs). The budget analysis shows that the water movement is complex and varies based on the aquifer geometry and location of pumping wells. Flow components between the unconfined and confined parts of the system were summarized by HUC11 (hydrologic unit code 11) basins.
Released May 30, 2024 14:16 EST
2024, Professional Paper 1814-G
Timothy White, David Sunderlin, Dwight Bradley
In this paper, we provide new information on the stratigraphy and paleoflora of the Sheep Creek volcanic field in the Alaska Range that bolsters our understanding of a key interval in the tectonic, paleoclimate, and paleoenvironmental history of the northern Cordillera. Although the distribution and basic stratigraphy of these rocks have been previously reported, here we document the stratigraphic context of recently dated igneous rocks and paleosols ranging from the Paleocene–Eocene boundary to the early middle Eocene, describe a more complete fossil leaf flora from the succession, and place the Sheep Creek volcanic field in its regional tectonic context of ridge subduction and slab window migration in central Alaska.
Released May 29, 2024 09:52 EST
2024, Fact Sheet 2024-3015
David W. Houseknecht, Craig P. Markey, Tracey J. Mercier, Christopher J. Schenk, Christopher D. Connors, Jared T. Gooley, Palma J. Botterell, Rebecca A. Smith, William A. Rouse, Christopher P. Garrity
Using a geology-based assessment methodology, the U.S. Geological Survey estimated mean volumes of 1.8 billion barrels of oil and 119.9 trillion cubic feet of gas technically recoverable from undiscovered, conventional accumulations in Cretaceous and Cenozoic strata of the North Chukchi Basin.
Released May 29, 2024 09:39 EST
2024, New Phytologist
Isa del Toro, Madelon Florence Case, Allison Karp, Jasper Slingsby, A. Carla Staver
- Increasing atmospheric CO2is changing the dynamics of tropical savanna vegetation. C3trees and grasses are known to experience CO2fertilization, whereas responses to CO2by C4grasses are more ambiguous.
- Here, we sample stable carbon isotope trends in herbarium collections of South African C4and C3grasses to reconstruct13C discrimination.
- We found that C3grasses showed no trends in13C discrimination over the past century but that C4grasses increased their13C discrimination through time, especially since 1950. These changes were most strongly linked to changes in atmospheric CO2rather than to trends in rainfall climatology or temperature.
- Combined with previously published evidence that grass biomass has increased in C4-dominated savannas, these trends suggest that increasing water-use efficiency due to CO2fertilization may be changing C4plant–water relations. CO2fertilization of C4grasses may thus be a neglected pathway for anthropogenic global change in tropical savanna ecosystems.
Released May 29, 2024 06:59 EST
2024, Water Research (259)
James F. Walsh, Randall J. Hunt, Anita C. Anderson, David W. Owens, Nancy Rice
Yearlong, event based, microbiological and chemical sampling was conducted at four public water supply well sites spanning a range of geologic settings and well depths to look for correlation between precipitation events and microbial occurrence. Near-continuous monitoring using autosamplers occurred just before, during, and after 5–7 sampling events triggered by rainfall and/or snowmelt. Microbial genetic material was noted at all four locations during all but one sampling event, but was exceedingly variable in time, where one sample would have no detections and the next sample could be a relatively high concentration. The highest microbial sums (microbial concentrations summed over an event) were observed during months in which precipitation exceeded historical averages. Extended wet conditions through the spring thaw resulted in the highest percentage of microbial positive samples, though at relatively low concentrations. Sampling events that followed drier than normal periods showed longer lag times between the onset of precipitation and microbial occurrence, as well as lower microbial detection rates. Although a general lag time pattern was observed at each site, the largest offset in time was observed at the site with the greatest depth to water. The study's temporally dense representation of drinking water pathogen characterization suggests that single event or infrequent periodic sampling of a drinking water supply cannot provide a representative characterization of the probability that pathogens are present, which likely has ramifications for calculating health risk assessments.
Released May 28, 2024 08:27 EST
2024, Ecology of Freshwater Fish
Matthew J. O'Donnell, Amy M. Regish, Stephen D. McCormick, Benjamin Letcher
The recent miniaturisation of implantable temperature recording tags has made measuring the water temperatures fish experience in the wild possible, but there may be a body size-dependent delay in implanted tag response time to changes in external temperature. To determine whether fish body size affects the response rate of implanted temperature tags, we implanted 20Salvelinus fontinalis(127–228 mm fork length (FL), 15.1–120.4 g) with temperature recording tags and subjected them to rapid temperature changes (±8°C in less than 2 seconds) in the laboratory. We found that thermal transfer rates, and the lag in temperature tag response rate, was positively correlated with fish size, but the direction of temperature change (colder or warmer) had no significant effect. In fish exposed to a slower rate of temperature change (2°C h−1) implanted tags did not show a response lag. Understanding the limitations of this important technology is crucial to determining the utility of the data it produces and its ability to accurately measure fish thermal experience in the wild.
Released May 28, 2024 06:43 EST
2024, Journal of Veterinary Diagnostic Investigation
Adrienne Barrett, Kali Holder, Susan Knowles, Elise E. B. LaDouceur
American pikas (Ochotona princeps) are small lagomorphs that live in mountainous talus areas of western North America. Studies on the histopathology of American pikas are limited. We summarize here the clinical histories, and gross and histologic findings of 12 American pikas, including 9 captive (wild-caught) and 3 wild animals. Death was often attributed to stress (transport, handling, anesthesia) with few-to-no premonitory clinical signs. Infection was the cause of death in 2 cases: 1 had bacterial pyogranulomatous dermatitis, cellulitis, and lymphadenitis with sepsis; the other case had oomycete-induced necrotizing colitis. Incidental parasitic infections included sarcocystosis, nematodosis (oxyurids), and ectoparasitism. Most animals with adequate nutritional status had periportal hepatic lipidosis; this finding was absent in all animals with adipose atrophy, and it is possible that periportal hepatic lipidosis is non-pathologic in American pikas. Three cases had myocardial necrosis that was considered the cause of death; the cause of necrosis was not determined, but it may have been caused by stress or vitamin E–selenium deficiency. Esophageal hyperkeratosis was noted in animals with a history of anorexia and negative energy balance; accumulation of esophageal keratin can result from lack of mucosal abrasion by ingesta. Several histologic findings that are likely normal in American pikas include splenic extramedullary hematopoiesis, thymic tissue in adults, andClostridiumsp. in the enteric lumen.
Released May 27, 2024 06:44 EST
2024, Nature Geoscience
Joshua Allen Crozier, Josef Dufek, Leif Karlstrom, Kyle R. Anderson, Ryan Cain Cahalan, Weston Thelen, Mary Catherine Benage, Chao Liang
Explosive volcanic eruptions produce hazardous atmospheric plumes composed of tephra particles, hot gas and entrained air. Such eruptions are generally driven by magmatic fragmentation or steam expansion. However, an eruption mechanism outside this phreatic–magmatic spectrum was suggested by a sequence of 12 explosive eruptions in May 2018 at Kīlauea, Hawaii, that occurred during the early stages of caldera collapse and produced atmospheric plumes reaching 8 km above the vent. Here we use seismic inversions for reservoir pressure as a source condition for three-dimensional simulations of transient multiphase eruptive plume ascent through a conduit and stratified atmosphere. We compare the simulations with conduit ascent times inferred from seismic and infrasound data, and with plume heights from radar data. We find that the plumes are consistent with eruptions caused by a stomp-rocket mechanism involving the abrupt subsidence of reservoir roof rock that increased pressure in the underlying magma reservoir. In our model, the reservoir was overlain by a pocket of accumulated high-temperature magmatic gas and lithic debris, which were driven through a conduit approximately 600 m long to erupt particles at rates of around 3,000 m3 s−1. Our results reveal a distinct collapse-driven type of eruption and provide a framework for integrating diverse geophysical and atmospheric data with simulations to gain a better understanding of unsteady explosive eruptions.
Released May 24, 2024 09:56 EST
2024, Scientific Investigations Report 2023-5141
Alan Mair, Delwyn S. Oki, Heidi L. Kāne, Adam G. Johnson, Kolja Rotzoll
The Water-budget Accounting for Tropical Regions Model (WATRMod) code was used for Kauaʻi, Oʻahu, Molokaʻi, Maui, and the Island of Hawaiʻi to estimate the spatial distribution of groundwater recharge, soil moisture, evapotranspiration, and climatic water deficit for a set of water-budget scenarios. The scenarios included historical and future drought conditions, and a land-cover condition where shrubland and forest within the cloud zone were converted to grassland. For the historical drought condition, island-wide mean annual recharge estimates range from a decrease of 30 percent (239 million gallons per day [Mgal/d]) for Kauaʻi to a decrease of 39 percent (2,706 Mgal/d) for the Island of Hawaiʻi, relative to the reference condition consisting of 1978–2007 rainfall and 2020 land cover. For the future drought condition, estimates of island-wide mean annual recharge range from a decrease of 40 percent (477 Mgal/d) on Maui to a decrease of 51 percent (116 Mgal/day) on Molokaʻi. Complete conversion of all shrubland and forest within the cloud zone to grassland for each drought condition produces estimated land-cover-related decreases in island-wide mean annual recharge (in addition to the drought-related decreases) of 11–12 Mgal/d on Oʻahu, 119–135 Mgal/day on Maui, and 689–849 Mgal/d on the Island of Hawaiʻi. The spatial distributions of increases in conditions indicative of moisture stress and potential wildfire hazard were quantified using the relative frequency of soil moisture less than a selected threshold value (monthly mean soil moisture less than 0.074, expressed as a fraction of available water capacity), evapotranspiration less than a selected threshold value (monthly evapotranspiration less than 0.96 inches), and climatic water deficit greater than a selected threshold value (monthly climatic water deficit greater than 0.77, expressed as fraction of potential evapotranspiration). For the historical drought condition, the greatest increases in the relative frequency for the moisture-stress indicators occur across parts of east and southwest Kauaʻi; central, east, and west Oʻahu; central Molokaʻi; central Maui and low- to mid-altitude parts of West Maui volcano; and the northwestern and southern parts of the Island of Hawaiʻi. For the future drought condition, the greatest increases in the relative frequency of the moisture-stress indicators occur across parts of west Kauaʻi; central and west Oʻahu and Molokaʻi; a band of mid-altitude area on the southern slope of West Maui volcano and across the southwestern slope of Haleakalā; and mid-altitude areas of the northwestern and southern parts of the Island of Hawaiʻi. Complete conversion of all shrubland and forest within the cloud zone to grassland for each drought condition results in land-cover-related increases in the relative frequency of moisture-stress indicators around Kaʻala in the Waiʻanae Range and the southeastern part of the Koʻolau Range on Oʻahu, the southern part of West Maui volcano and the southwestern slope of Haleakalā on Maui, and the upland regions of the western and southern parts of the Island of Hawaiʻi.
Released May 24, 2024 09:56 EST
2024, Ocean Science (20) 661-688
Kimberly Yates, Zachery Fehr, Selena Anne-Marie Johnson, David G. Zawada
Understanding event-driven sediment transport in coral reef environments is essential to assessing impacts on reef species, habitats, restoration, and mitigation, yet a global knowledge gap remains due to limited quantitative studies. Hurricane Irma made landfall in the Lower Florida Keys with sustained 209 km h−1winds and waves greater than 8 m on 10September2017, directly impacting the Florida Reef Tract (FRT) and providing an opportunity to perform a unique comprehensive, quantitative assessment of its impact on coral reef structure and sediment redistribution. We used lidar and multibeam derived digital elevation models (DEMs) collected before and after the passing of Hurricane Irma over a 15.98 km2area along the lower FRT including Looe Key Reef to quantify changes in seafloor elevation, volume, and structure due to storm impacts. Elevation change was calculated at over 4million point locations across 10 habitat types within this study area for two time periods using data collected (1)approximately 1year before the passing of Irma and 3 to 6months following the storm's impact as well as (2)3 to 6months after and up to 16.5 months after the storm. Elevation change data were then used to generate triangulated irregular network (TIN) models in ArcMap to calculate changes in seafloor volume during each time period. Our results indicate that Hurricane Irma was primarily a depositional event that increased mean seafloor elevation and volume at this study site by 0.34 m and up to 5.4 Mm3, respectively. Sediment was transported primarily west-southwest (WSW) and downslope, modifying geomorphic seafloor features including the migration of sand waves and rubble fields, formation of scour marks in shallow seagrass habitats, and burial of seagrass and coral-dominated habitats. Approximately 16.5 months after Hurricane Irma (during a 13-month period between 2017 and 2019), net erosion was observed across all habitats with mean elevation change of−0.15 m and net volume change up to−2.46 Mm3. Rates of elevation change during this post-storm period were 1to 2orders of magnitude greater than decadal and multi-decadal rates of change in the same location, and changes showed erosion of approximately 50 % of sediment deposited during the storm event as seafloor sediment distribution began to re-equilibrate to non-storm sea-state conditions. Our results suggest that higher-resolution elevation change data collected over seasonal and annual time periods could enhance characterization and understanding of short-term and long-term rates and processes of seafloor change.
Released May 24, 2024 09:48 EST
2024, Scientific Investigations Report 2023-5130
Heidi L. Kāne, Alan Mair, Adam G. Johnson, Kolja Rotzoll, James Mifflin, Delwyn S. Oki
Demand for freshwater in the State of Hawaiʻi is expected to increase by roughly 13 percent from 2020 to 2035. Groundwater availability in Hawaiʻi is affected by a number of factors, including land cover, rainfall, runoff, evapotranspiration, and climate change. To evaluate the availability of fresh groundwater under projected future-climate conditions, estimates of groundwater recharge are needed. A water-budget model with a daily computation interval was used to estimate the spatial distribution of groundwater recharge for Kauaʻi, Oʻahu, Molokaʻi, Lānaʻi, Maui, and the Island of Hawaiʻi for recent climate conditions and three future-climate scenarios. Climate conditions from 1978 to 2007 were used as the reference period for recent climate conditions on each island. The three future-climate scenarios were developed using available high-resolution downscaled climate projections that include (1) a mid-century scenario using projected rainfall conditions for the Representative Concentration Pathway (RCP) scenario during 2041–71 with a total radiative forcing of 8.5 watts per square meter by the year 2100 (RCP8.5 2041–71 scenario), (2) a dry-climate scenario using projected rainfall conditions for the RCP8.5 scenario during 2071–99, and (3) a wet-climate scenario using projected rainfall conditions for the “Special Report on Emissions Scenarios” A1B scenario during 2080–99 for Maui, the RCP4.5 scenario during 2080–99 for Kauaʻi, Lānaʻi, and the Island of Hawaiʻi, and the RCP8.5 scenario during 2080–99 for Oʻahu and Molokaʻi. An additional drought scenario was added for Lānaʻi to assess the effect of extreme drought conditions during 2008–12 on groundwater recharge. All scenarios used 2020 land cover.
Mean annual groundwater recharge is estimated to decrease between 5 and 55 percent on all six islands in this study for the mid-century and dry-climate scenarios relative to the reference-period recharge. Recharge is estimated to increase for Kauaʻi, Oʻahu, Molokaʻi, Lānaʻi, and Maui between 2 and 43 percent and decrease for the Island of Hawaiʻi by about 4 percent for the wet-climate scenario. Comparing the mid-century and dry-climate scenarios, all 110 aquifer systems (management areas defined by the State of Hawaiʻi Commission on Water Resource Management) from all six islands show similar direction in drying (104 aquifer systems) or wetting (6 aquifer systems) changes for recharge. However, among the three future scenarios, only 35 of 110 aquifer systems show similar direction in drying (30 aquifer systems) or wetting (5 aquifer systems) changes for recharge.
Released May 24, 2024 09:27 EST
2024, Landscape Ecology (39)
Andrii Zaiats, Megan E Cattau, David Pilliod, Rongsong Liu, Patricia Kaye T. Dumandan, Ahmad Hojatimalekshah, Donna M. Delparte, Trevor Caughlin
Context
Dynamic feedbacks between physical structure and ecological function drive ecosystem productivity, resilience, and biodiversity maintenance. Detailed maps of canopy structure enable comprehensive evaluations of structure–function relationships. However, these relationships are scale-dependent, and identifying relevant spatial scales to link structure to function remains challenging.
Objectives
We identified optimal scales to relate structure heterogeneity to ecological resistance, measured as the impacts of wildfire on canopy structure, and ecological resilience, measured as native shrub recruitment. We further investigated whether structural heterogeneity can aid spatial predictions of shrub recruitment.
Methods
Using high-resolution imagery from unoccupied aerial systems (UAS), we mapped structural heterogeneity across ten semi-arid landscapes, undergoing a disturbance-mediated regime shift from native shrubland to dominance by invasive annual grasses. We then applied wavelet analysis to decompose structural heterogeneity into discrete scales and related these scales to ecological metrics of resilience and resistance.
Results
We found strong indicators of scale dependence in the tested relationships. Wildfire effects were most prominent at a single scale of structural heterogeneity (2.34m), while the abundance of shrub recruits was sensitive to structural heterogeneity at a range of scales, from 0.07 – 2.34m. Structural heterogeneity enabled out-of-site predictions of shrub recruitment (R2 = 0.55). The best-performing predictive model included structural heterogeneity metrics across multiple scales.
Conclusions
Our results demonstrate that identifying structure–function relationships requires analyses that explicitly account for spatial scale. As high-resolution imagery enables spatially extensive maps of canopy heterogeneity, models for scale dependence will aid our understanding of resilience mechanisms in imperiled arid ecosystems.
Released May 24, 2024 07:03 EST
2024, JGR Earth Surface (129)
SeanPaul La Selle, Alan R. Nelson, Robert C. Witter, Bruce E. Jaffe, Guy Gelfenbaum, Jason Scott Padgett
The 26 January 1700 CE Cascadia subduction zone earthquake ruptured much of the plate boundary and generated a tsunami that deposited sand in coastal marshes from northern California to Vancouver Island. Although the depositional record of tsunami inundation is extensive in some of these marshes, few sites have been investigated in enough detail to map the inland extent of sand deposition and depict variability in tsunami deposit thickness and grain size. We collected 129 cores in marshes of the Salmon River estuary in Oregon and reanalyzed 114 core logs from a 1987–88 study that mapped the inland extent of circa 1700 CE sandy tsunami deposits. The ca. 1700 CE tsunami deposit in the Salmon River estuary is easily recognized in cores ≤1m deep in which a buried marsh peat is overlain by a well sorted sand bed with a sharp lower contact that thins and fines inland. We use tsunami deposit data and models of sandy tsunami sediment transport (using Delft3D-FLOW) to test 15 rupture models that could represent a ca. 1700 CE earthquake. At least 12–16m of slip offshore of the Salmon River, which results in 0.8–1.0m of coastal coseismic subsidence, is required to match the ca. 1700 CE sand deposit's inland extent, which is consistent with models of heterogeneous megathrust slip in ca. 1700 CE. Our methods of detailed tsunami deposit mapping, combined with sediment transport modeling, can be used to test models of megathrust ruptures and their tsunamis to potentially improve earthquake and tsunami hazard assessments.
Released May 24, 2024 06:50 EST
2024, Scientific Investigations Report 2024-5016
Nathaniel J. Schaepe, Mikaela L. Cherry, Amanda T. Flynn, Christopher M. Hobza
Population in western Sarpy County, Nebraska, has steadily increased over the last several decades and has led to increased groundwater use for domestic purposes. To meet the increase in demand, the Papio-Missouri River Natural Resources District is seeking to use all available sources of groundwater in western Sarpy County. Additionally, elevated groundwater nitrate plus nitrite as nitrogen concentrations were detected, indicating the need to better understand the groundwater quality of the area. Although the general geology of the area is understood, the area does not have detailed information on the extent of the various aquifers, particularly the Dakota aquifer. To characterize these aquifers, the Papio-Missouri River Natural Resources District invested in airborne electromagnetic surveys of the area to better understand the subsurface geology. Although these surveys improved understanding of the groundwater systems in the area, the Papio-Missouri River Natural Resources District wanted to integrate the subsurface information with available water-quality and groundwater-level data.
In response, the U.S. Geological Survey, in cooperation with the Papio-Missouri River Natural Resources District, the Nebraska Natural Resources Commission, and the Nebraska Department of Natural Resources, assembled geologic, hydrogeologic and nitrate plus nitrite as nitrogen information for the selected area into a three-dimensional visualization computer software package called GeoScene3D. The completed GeoScene3D project was assembled to provide a visualization of the groundwater systems and associated water-quality results in Sarpy County and to provide the Papio-Missouri River Natural Resources District managers with information that can be used to make more informed groundwater resource-planning decisions in the future. This report details the development of a three-dimensional model created within GeoScene3D to visualize the subsurface, particularly the Dakota Sandstone in western Sarpy County.
Released May 24, 2024 06:48 EST
2024, Report
Maggie Hunter, Kristian Meissner, Catherine Abbott, Florien Leese, Gernot Segelbacher
The widespread adoption of environmental DNA (eDNA) detection tools for biodiversity monitoring has led to the need for universal data standards to inform principled eDNA data applications. Improvements in understanding the meaning and possible uncertainty of eDNA data can minimize erroneous conclusions, increase confidence in eDNA data, and maximize conservation outcomes.-Environmental DNA (eDNA) is the genetic material left by organisms in the environment.-eDNA is increasingly being used to detect the presence of species and assess biodiversity, but broad-scale best practices are still being developed.-This affects the quality, accessibility, and usefulness of data.-Non-invasive eDNA sampling can complement or enhance conventional approaches, as it can be a highly sensitive, rapid, and cost-effective tool for biodiversity monitoring.-Creating unified eDNA data best practices and developing DNA reference libraries will ensure eDNA detection methods are applied consistently to accurately inform conservation and wildlife management.
Released May 24, 2024 06:35 EST
2024, Frontiers in Ecology and Evolution (12)
Laura Lukens, Jennifer Thieme, Wayne E. Thogmartin
The global decline of pollinators, particularly insects, underscores the importance of enhanced monitoring of their populations and habitats. However, monitoring some pollinator habitat is challenging due to widespread species distributions and shifts in habitat requirements through seasons and life stages. The monarch butterfly (Danaus plexippus), a migratory insect pollinator that breeds widely throughout North America, presents a unique case study for testing a sampling framework to overcome these challenges. Monarchs exhibit discrete resource needs across life stages (e.g., larval requirement for milkweed, adult requirement for floral nectar), utilizing many land use types across their extensive geographic range during breeding and migration seasons. The Integrated Monarch Monitoring Program (IMMP) uses a standardized protocol with a generalized random tessellation stratified (GRTS) sampling design to gather spatially balanced and ecologically representative information on monarch habitats within the United States. The IMMP is applicable to various land use types and habitats used by breeding monarchs and may be extended to sites outside of the GRTS design to collect data on non-random sites of interest, such as legacy or conservation sites. Additionally, the IMMP’s modular design and publicly available training allows for broad participation, including involvement from community scientists. Here, we summarize habitat metrics (milkweed and floral resources) across 1,233 sites covering much of the monarch’s breeding range. We examine variation in milkweed density and floral resource availability on probabilistic (random) and non-probabilistic (convenience) samples and among land use types (site types). Additionally, we assess resource availability within core geographies for monarch breeding and migration, specifically within the U.S. Fish and Wildlife Service’s Monarch Conservation Units (western, northern, and southern United States). Milkweed density, floral frequency, and floral richness were higher on non-random sites and in the North region. Among site types, milkweed density was highest on Rights-of-Way and Unclassified Grassland, while floral frequency was lowest on Rights-of-Way. The IMMP represents the first field-based habitat monitoring program of this scale for monarchs, yielding a robust dataset on monarchs and their habitats across their breeding range and offering a framework for surveying the habitat of insect species with diverse habitat requirements or widespread distributions.
Released May 23, 2024 16:10 EST
2024, Fact Sheet 2024-3013
Lisa McKeon, Todd Wojtowicz
Early detection of biological threats, such as invasive species, increases the likelihood that control efforts will be successful and cost-effective. Environmental deoxyribonucleic acid (eDNA) sampling is an established method for the efficient and sensitive early detection of new biological threats. The Rapid eDNA Assessment and Deployment Initiative & Network (READI-Net) is a project designed with partners to provide a full suite of tools to maximize the power of eDNA sampling for detecting invasive species. The READI-Net suite of tools will include the availability of autonomous eDNA samplers, multispecies molecular DNA detection tools, strategic sample design, standardized and repeatable lab analysis, and a communication framework to deliver eDNA detection results to inform invasive species science, policy, and management. The READI-Net project is part of a national strategy to implement eDNA sampling for the early detection of and rapid response to biological threats.
Released May 23, 2024 16:10 EST
2024, Fact Sheet 2024-3012
Todd Wojtowicz
The U.S. Geological Survey (USGS) Northern Rocky Mountain Science Center is based in Bozeman, Montana, and has field offices in Glacier National Park, Mont.; Missoula, Mont.; and Knoxville, Tennessee. Our scientists respond to the natural resource management needs of Federal, Tribal, and State partners—directly engaging in the coproduction and application of integrated, interdisciplinary science—and perform place-based research throughout the northern Rocky Mountains, including Yellowstone and Glacier National Parks and the northern Great Plains. However, the scope and implications of our research extend across the Nation. Our research themes are as follows: (1) climate change and drought, (2) species at risk, (3) habitat in changing landscapes, and (4) invasive species and wildlife disease. This Fact Sheet highlights examples of dynamic partnerships and key advances in our themes in fiscal year 2023 (October 2022–September 2023).
Released May 23, 2024 14:56 EST
2024, Scientific Investigations Map 2932-E
Frank A. Trusdell, John P. Lockwood
Mauna Loa, the largest active volcano on Earth, has erupted 34 times since written descriptions became available in A.D. 1832. The most recent eruption of Mauna Loa occurred on November 27, 2022, after a 38 year hiatus; it lasted for 12 days. Some eruptions began with only brief seismic unrest, whereas others followed several months to a year of increased seismicity. Once underway, Mauna Loa’s eruptions can produce lava flows that may reach the sea in less than 24 hours, severing roads and utilities. For example, lava flows that erupted from the Southwest Rift Zone in 1950 advanced at an average rate of 9.3 kilometers per hour (5.8 miles per hour); all three lobes reached the ocean within ~24 hours. Near the eruptive vents, the flows likely traveled even faster. In terms of eruption frequency, pre-eruption warning, and rapid flow emplacement, Mauna Loa has great volcanic-hazard potential for the Island of Hawai‘i. Volcanic hazards on Mauna Loa can be anticipated, and risk substantially mitigated, by documenting its past activity to refine our knowledge of the hazards, and by alerting the public and local government officials of our findings and their implications for hazards assessments and risk.
The map of the north and west flanks of Mauna Loa shows the distribution and relation of volcanic and surficial sedimentary deposits. It incorporates previously reported work published as generalized small-scale maps and a more detailed map.
Within the mapped area, lava has flowed from three different source regions: the Northeast Rift Zone (22 percent), the summit (64 percent), and radial vents (14 percent). All three have different points of origin which, in turn, affect the flow characteristics and periodicity of activity.
The map area includes the uppermost part of the NERZ and extends from the highest elevation––13,040 feet at the south end of the Kokoolau quadrangle, just below the summit caldera––to the sea northwest and west of the summit. Lava that erupts from the north and west flanks typically flows to the west, northwest, or north, depending on the vent location. Both morphologic lava flow types—‘a‘ā and pāhoehoe—are present. Pāhoehoe units tend to spread out or widen in low-slope regions, such as in the saddle regions between Mauna Loa and Mauna Kea or between Mauna Loa and Hualālai. In comparison, ʻaʻā flows generally produce narrower flow lobes that have higher relief.
This map is the fifth in a series of five maps that will cover Mauna Loa volcano.
NOTE: Map sheet 1 contains lines and type with overprint. This feature may be turned on or off in the Adobe Acrobat page display preferences.
Released May 23, 2024 13:05 EST
2024, Circular 1520
Victoria G. Christensen, Christopher J. Crawford, Robert J. Dusek, Michael J. Focazio, Lisa Reynolds Fogarty, Jennifer L. Graham, Celeste A. Journey, Mari E. Lee, James H. Larson, Sarah M. Stackpoole, Viviana Mazzei, Emily J. Pindilli, Barnett A. Rattner, E. Terrence Slonecker, Kristen B. McSwain, Timothy J. Reilly, Ashley E. Lopez
Algal blooms in water, soils, dusts, and the environment have captured national attention because of concerns associated with exposure to algal toxins for humans and animals. Algal blooms naturally occur in all surface-water types and are important primary producers for aquatic ecosystems. However, excessive algae growth can be associated with many harmful effects ranging from aesthetic to toxicity concerns, so this excessive growth is commonly called a harmful algal bloom (HAB).
Ecological imbalances that can lead to excessive algal growth, such as increased nutrient availability to waterbodies from natural and anthropogenic sources, are well documented in scientific literature. On the other hand, fundamental scientific understandings of environmental causes and controls leading to algal toxin production, environmental exposures, and adverse health outcomes for humans and animals could benefit from more attention by U.S. Geological Survey (USGS) scientists. Understanding when, why, and how the toxin is produced by individual algal cells or communities and why the toxin is released to the surrounding waterbody requires fundamental research to determine a toxin’s role, whether it provides competitive advantage or if other potential reasons exist for toxin production and release, such as secretions from otherwise benign biological processes. This research will require groundbreaking scientific discovery about underlying biologic and abiotic (non-living) processes commonly complicated by local variation in land use, microbial species composition, and ecosystem structure of the surrounding watershed.
Although underlying processes by which HABs form may be similar from one waterbody to another, individual waterbodies may be controlled by local factors for HAB development and toxin production that are unique to the watershed. Consequently, many fundamental science gaps exist that prevent informed mitigation and prevention of toxic HAB events. There are also gaps in understanding local conditions that control algal growth unique to specific watersheds. Addressing these science gaps is needed to inform evidence-based decisions that protect human and animal health and that reduce recreational and socioeconomic losses.
Released May 23, 2024 09:30 EST
2024, Scientific Investigations Report 2023-5064-D
Sara B. Levin
This study characterizes hydroclimatic variability and change in peak streamflow and daily streamflow in Michigan from water years 1921 through 2020. Four analysis periods were examined: the 100-year period from water year 1921 through 2020, the 75-year period from water year 1946 through 2020, the 50-year period from water year 1971 through 2020, and the 30-year period from water year 1991 through 2020. Peak streamflow and climate data were available at 4, 29, 50, and 30 streamgages in the 100-, 75-, 50-, and 30-year periods, respectively. Daily streamflow was available for 4, 29, 74, and 79 streamgages in the 100-, 75-, 50-, and 30-year periods, respectively.
Peak streamflow for each streamgage and analysis period was assessed for monotonic trends and change points. Trends in peak streamflow were predominantly upward, with some isolated downward trends throughout the southern half of Michigan for all four analysis periods. Trends in the Upper Peninsula were downward in 75- and 50-year analysis periods and upward or neutral in the 30-year period. Upward trends in peak flows were largely driven by increases in precipitation, which occurred at nearly every streamgage in all analysis periods, with the greatest magnitude trends in winter and spring in the 50- and 30-year periods.
Released May 23, 2024 07:00 EST
2024, Nature Water (2) 419-433
Rosemary W.H. Carroll, Richard G. Niswonger, Craig Ulrich, Charuleka Varadharajan, Erica Siirila-Woodburn, Kenneth H. Williams
Groundwater interactions with mountain streams are often simplified in model projections, potentially leading to inaccurate estimates of streamflow response to climate change. Here, using a high-resolution, integrated hydrological model extending 400 m into the subsurface, we find groundwater an important and stable source of historical streamflow in a mountainous watershed of the Colorado River. In a warmer climate, increased forest water use is predicted to reduce groundwater recharge resulting in groundwater storage loss. Losses are expected to be most severe during dry years and cannot recover to historical levels even during simulated wet periods. Groundwater depletion substantially reduces annual streamflow with intermittent conditions predicted when precipitation is low. Expanding results across the region suggests groundwater declines will be highest in the Colorado Headwater and Gunnison basins. Our research highlights the tight coupling of vegetation and groundwater dynamics and that excluding explicit groundwater response to warming may underestimate future reductions in mountain streamflow.
Released May 23, 2024 06:45 EST
2024, Rangelands (46) 100-102
Matthew Germino
For this edition of Browsing the Literature, we have two new papers from Rangeland Ecology & Management, a series of basic ecology papers with an international scope from journals such as the Proceedings of the National Academy of Sciences (USA), Science, and Nature, and several papers advancing our understanding of drought and carbon at global scales. Additionally, several papers on sagebrush-steppe rangelands are covered with transferable insights to other rangeland types.
Released May 23, 2024 06:33 EST
2024, Journal of Experimental Marine Biology and Ecology (577)
Lindsey Stadler, Kristen Gorman, Vanessa R. von Biela, Andrew C. Seitz, Katrin Iken
Northern high-latitude glaciers impact nearshore marine ecosystems through the discharge of cold and fresh waters, including nutrients and organic matter. Fishes are important integrators of ecosystem processes and hold key positions in the transfer of energy to higher trophic positions in such systems. This study used a natural gradient in space and time, including watershed glacial cover (0–60%) of five adjacent estuaries and three sequential discharge periods (pre-peak, peak, post-peak) in the northern Gulf of Alaska (Kachemak Bay) to test whether differences in glacial cover of watersheds upstream of estuaries affect dietary resource use of nearshore fishes. Dietary resource use was assessed using stomach content and stable carbon and nitrogen isotope analyses to determine fish diet composition and trophic niche width. Crescent gunnel (Pholis laeta), a mostly sedentary species, was our focal species for comparisons across estuaries and discharge periods. Discharge period had a greater influence on diet composition and trophic niche width of crescent gunnels than watershed glacial coverage. Niche width of crescent gunnel was larger during the post-peak discharge period compared to pre-peak and peak periods, coincident with a shift in prey spectrum. However, watershed glacial cover was not a suitable predictor of niche width of crescent gunnel. Trophic resource use was also considered along this glacial cover gradient for two other fish species, Pacific staghorn sculpin (Leptocottus armatus) and starry flounder (Platichthys stellatus), but within the post-peak discharge period only. These species exploited a larger prey base compared to crescent gunnel, likely due to their greater mobility. Similar to crescent gunnel, there were no relationships in trophic niche width associated with watershed glacial coverage for these other species during the post-peak discharge period. Instead, trophic resource use of these three nearshore fish species was influenced by a more complex set of dynamic environmental variables (salinity, temperature, turbidity, and discharge), as well as static watershed characteristics, especially vegetation cover. Such drivers can act through changes in metabolic rates, modulating foraging strategies and trophic connectivity, as well as terrestrial nutrient delivery to support estuarine production. The environmental conditions associated with the glacially influenced estuaries during our study period (2020−2021) seemed within a range that allowed nearshore fishes to maintain energy pathways and prey bases across these estuaries, but it is unknown how these estuarine food webs may be influenced in years of extreme conditions such as during heat waves, droughts, or floods.
Released May 23, 2024 06:28 EST
2024, Water Resources Research (60)
Timothy O. Hodson, Thomas M. Over, Smith Tyler, Lucy A. Marshall
In machine learning or scientific computing, model performance is measured with an objective function. But why choose one objective over another? According to the information-theoretic paradigm, the “best” objective function is whichever minimizes information loss. To evaluate different objectives, transform them into likelihoods. The ratios of these likelihoods represent how strongly we should prefer one objective versus another, and the log of that ratio represents the relative information loss (or gain) from one objective to another. In plain terms, minimizing information loss is equivalent to minimizing uncertainty, as well as maximizing probability and general utility. We argue that this paradigm is well-suited to models that have many uses and no definite utility like the complex Earth system models used to understand the effects of climate change. Furthermore, the benefits of “maximizing information and general utility” extend beyond model accuracy to other important considerations including how efficiently the model calibrates, how well it generalizes, and how well it compresses data.
Released May 23, 2024 06:21 EST
2024, Frontiers in Genetics (15)
Yniv Palti, Roger L. Vallejo, Maureen K. Purcell, Guangtu Gao, Kristy L. Shewbridge, Roseanna L. Long, Christopher Setzke, Breno O. Fragomeni, Hao Cheng, Kyle E. Martin, Kerrry A. Naish
Infectious hematopoietic necrosis (IHN) is a disease of salmonid fish that is caused by the IHN virus (IHNV), which can cause substantial mortality and economic losses in rainbow trout aquaculture and fisheries enhancement hatchery programs. In a previous study on a commercial rainbow trout breeding line that has undergone selection, we found that genetic resistance to IHNV is controlled by the oligogenic inheritance of several moderate and many small effect quantitative trait loci (QTL). Here we used genome wide association analyses in two different commercial aquaculture lines that were naïve to previous exposure to IHNV to determine whether QTL were shared across lines, and to investigate whether there were major effect loci that were still segregating in the naïve lines. A total of 1,859 and 1,768 offspring from two commercial aquaculture strains were phenotyped for resistance to IHNV and genotyped with the rainbow trout Axiom 57K SNP array. Moderate heritability values (0.15–0.25) were estimated. Two statistical methods were used for genome wide association analyses in the two populations. No major QTL were detected despite the naïve status of the two lines. Further, our analyses confirmed an oligogenic architecture for genetic resistance to IHNV in rainbow trout. Overall, 17 QTL with notable effect (≥1.9% of the additive genetic variance) were detected in at least one of the two rainbow trout lines with at least one of the two statistical methods. Five of those QTL were mapped to overlapping or adjacent chromosomal regions in both lines, suggesting that some loci may be shared across commercial lines. Although some of the loci detected in this GWAS merit further investigation to better understand the biological basis of IHNV disease resistance across populations, the overall genetic architecture of IHNV resistance in the two rainbow trout lines suggests that genomic selection may be a more effective strategy for genetic improvement in this trait.
Released May 22, 2024 11:33 EST
2024, Scientific Investigations Report 2024-5031
Paul A. Ensminger, Daniel M. Wagner, Amanda Whaling
To improve flood-frequency estimates for rural streams in the Coastal Plain region of Louisiana, generalized least-squares regression techniques were used to relate corresponding annual exceedance probability streamflows for 211 streamgages in the region to a suite of explanatory variables that include physical, climatic, pedologic, and land-use characteristics of the streamgage drainage area. The resulting generalized least-squares models can be used to estimate selected annual exceedance probability streamflows for rural ungaged locations in the Coastal Plain region of Louisiana. For the 211 streamgages in the Coastal Plain region of Louisiana and surrounding States, annual peak-streamflow data available through the 2016 water year were used in this study. Two unique flood regions, the Mississippi Alluvial Plain and Coastal Plain, were identified as separate hydrologic regions based on statistical evaluation and significance of categorical variables representing the regions regressed against the 1-percent annual exceedance probability streamflow (the 100-year flood). Regional regression equations for estimating annual exceedance probability streamflow for the Mississippi Alluvial Plain region have been previously published; therefore, the purpose of this study was to generate updated regional regression equations for the Coastal Plain region of Louisiana. The final regression models used drainage area and channel slope as explanatory variables based on performance metrics.
Released May 22, 2024 10:14 EST
2024, Nature Communications (15)
Sarah R. Weiskopf, Forest Isbell, Maria Isabel Arce-Plata, Moreno Di Marco, Mike Harfoot, Justin A. Johnson, Susannah B. Lerman, Brian W. Miller, Toni Lyn Morelli, Akira S. Mori, Ensheng Weng, Simon Ferrier
Natural ecosystems store large amounts of carbon globally, as organisms absorb carbon from the atmosphere to build large, long-lasting, or slow-decaying structures such as tree bark or root systems. An ecosystem’s carbon sequestration potential is tightly linked to its biological diversity. Yet when considering future projections, many carbon sequestration models fail to account for the role biodiversity plays in carbon storage. Here, we assess the consequences of plant biodiversity loss for carbon storage under multiple climate and land-use change scenarios. We link a macroecological model projecting changes in vascular plant richness under different scenarios with empirical data on relationships between biodiversity and biomass. We find that biodiversity declines from climate and land use change could lead to a global loss of between7.44-103.14PgC (global sustainability scenario) and10.87-145.95PgC (fossil-fueled development scenario). This indicates a self-reinforcing feedback loop, where higher levels of climate change lead to greater biodiversity loss, which in turn leads to greater carbon emissions and ultimately more climate change. Conversely, biodiversity conservation and restoration can help achieve climate change mitigation goals.
Released May 22, 2024 08:41 EST
2024, Tectonics (43)
Katherine M. Biegel, Jeremy M. Gosselin, Jan Dettmer, Maurice Colpron, Eva Enkelmann, Jonathan Caine
Deformation in southeastern Alaska and southwest Yukon is governed by the subduction and translation of thePacific-Yakutat plates relative to the North American plate in the St. Elias region. Despite notable historical seismicity and major regional faults, studies of the region between the Fairweather and Denali faults are complicated by glacial coverage and the remote setting. In the last decade, significant improvements have been made to the density of regional broadband seismometer networks. We relocate more than 5,000 earthquakes between 2010 and 2021 in the region of southeastern Alaska and southwestern Yukon utilizing these improved seismic networks. With reductions in catalog uncertainty, particularly in depth, we quantify the thickness of the seismogenic layer in the crust throughout the region and locate seismicity on a shallow network of upper-crustal faults. Relocated earthquakes, combined with an updated focal-mechanism catalog, permit estimating and classifying motion of active faults. This includes mapping the Totschunda-Fairweather “Connector” fault, which plays an important role in explaining regional deformation, and identifying new faults like the Kathleen Lake fault. We draw similarities between our seismic observations and simplified conceptual models of regional tectonics, which describe a dominant transpressional regime and localized slip partitioning. Our results support a hypothesis where current deformation is taking place on a well-defined and evolved network of shallow faults in the corridor between the Totschunda-Fairweather “Connector” and Denali faults.
Released May 22, 2024 06:42 EST
2024, Journal of Geophysical Research: Solid Earth (129)
Joshua Allen Crozier, Kyle R. Anderson
In multiple observed caldera-forming eruptions, the rock overlying a draining magma reservoir dropped downward along ring faults in sequences of discrete collapse earthquakes. These sequences are analogous to tectonic earthquake cycles and provide opportunities to examine fault mechanics and collapse eruption dynamics over multiple events. Collapse earthquake cycles have been studied with zero-dimensional slider-block models, but these do not account for the complicated interplay between fluid and elastic dynamics or for factors such as the heterogeneous fault properties and non-vertical ring fault geometries often inferred at volcanoes. We present two-dimensional axisymmetric mafic piston-like collapse earthquake cycle models that include rate-and-state friction, fully-dynamic elasticity, and compressible viscous fluid magma flow. We demonstrate that collapse earthquake intervals and magnitudes are highly sensitive to inertial effects, evolving stress fields, fault geometry, and depth-varying fault friction. Given the consistent earthquake cycles observed in most eruptions, this suggests that ring faults can quickly stabilize and often become nearly vertical at depth. We use the well-monitored 2018 collapse sequence at Kı̄lauea as a case study. Our model can produce many features of Kı̄lauea seismic and geodetic observations, except for a significant amount of interseismic slip, which cannot be readily explained with simple rate-and-state friction parameterizations.
Released May 21, 2024 09:43 EST
2024, Canadian Journal of Fisheries and Aquatic Sciences
Paul McLaughlin, Kevin Krause, Kelly O. Maloney, Taylor E Woods, Tyler Wagner
Accurately predicting species’ distributions is critical for the management and conservation of fish and wildlife populations. Joint Species Distribution Models (JSDMs) account for dependencies between species often ignored by traditional species distribution models. We evaluated how a JSDM approach could improve predictive strength for stream fish communities within large watersheds (the Chesapeake Bay Watershed, USA), using a cross-validation study of JSDMs fit to data from over 50 species. Our results suggest that conditional predictions from JSDMs have the potential to make large improvements in predictive accuracy for many species, particularly for more generalist species where single species models may not perform well. For some species there was no added explanatory effect from conditional information, most of which already exhibited strong marginal predictive ability. For several rare species there were significant improvements in occurrence predictions, while the results for two invasive species considered did not show the same improvements. Overall, the optimal number of species to condition upon, as well as the effects of conditioning upon an increasing number of species, varied widely among species.
Released May 21, 2024 07:01 EST
2024, Article
Eveling A. Tavera, David B. Lank, David C. Douglas, Brett K. Sanderco*ck, Richard B. Lanctot, Niels M. Schmidt, Jeroen Reneerkens, David H. Ward, Joel Bety, Eunbi Kwon, Nicolas Lecomte, Cheri L Gratto-Trevor, Paul A. Smith, Willow B. English, Sarah T. Saalfeld, Stephen C. Brown, H. River Gates, Erica Nol, Joseph R. Liebezeit, Rebecca L. McGuire, Laura McKinnon, Steve Kendall, Martin D. Robards, Megan Boldenow, David C. Payer, Jennie Rausch, Mikhail Soloviev, Diana V. Solovyeva, Steve Zack, Jordyn Stalwick, Kirsty E. B. Gurney
Global climate change has altered the timing of seasonal events (i.e., phenology) for a diverse range of biota. Within and among species, however, the degree to which alterations in phenology match climate variability differ substantially. To better understand factors driving these differences, we evaluated variation in timing of nesting of eight Arctic-breeding shorebird species at 18 sites over a 23-year period. We used the Normalized Difference Vegetation Index as a proxy to determine the start of spring (SOS) growing season and quantified relationships between SOS and nest initiation dates as a measure of phenological responsiveness. Among species, we tested four life history traits (migration distance, seasonal timing of breeding, female body mass, expected female reproductive effort) as species-level predictors of responsiveness. For one species (Semipalmated Sandpiper), we also evaluated whether responsiveness varied across sites. Although no species in our study completely tracked annual variation in SOS, phenological responses were strongest for Western Sandpipers, Pectoral Sandpipers, and Red Phalaropes. Migration distance was the strongest additional predictor of responsiveness, with longer-distance migrant species generally tracking variation in SOS more closely than species that migrate shorter distances. Semipalmated Sandpipers are a widely distributed species, but adjustments in timing of nesting relative to variability in SOS did not vary across sites, suggesting that different breeding populations of this species were equally responsive to climate cues despite differing migration strategies. Our results unexpectedly show that long-distance migrants are more sensitive to local environmental conditions, which may help them to adapt to ongoing changes in climate.
Released May 21, 2024 06:44 EST
2024, Journal of Geophysical Research, Earth Surface (129)
E. Lundsten, Charles K. Paull, R. Gwiazda, S. Dobbs, D.W. Caress, Linda A. Kuhnz, M. Walton, N. Nieminski, Mary McGann, Thomas Lorenson, Guy R. Cochrane, Jason A. Addison
Recent surface ship multibeam surveys of the Sur Pockmark Field, offshore Central California, reveal >5,000 pockmarks in an area that is slated to host a wind farm, between 500- and 1,500-m water depth. Extensive fieldwork was conducted to characterize the seafloor environment and its recent geologic history, including visual observations with remotely operated vehicles, sediment core sampling, and high-resolution, near-bottom Chirp and multibeam surveys collected with autonomous underwater vehicles to capture the morphology and stratigraphy of the pockmarks. No evidence of high methane concentrations in sediments, chemosynthetic biological communities, or methane-derived diagenetic byproducts was found. Chirp data and sediment cores showed alternating layers of slowly accumulating hemipelagic drapes interrupted by more reflective turbidite horizons that extend throughout the pockmark field and beyond. Chirp data showed multiple episodes of lateral migration over time in some of the pockmarks in association with erosion and infilling events. Laterally continuous turbidite horizons that overlay erosional surfaces indicated that pockmark migration occurred synchronously in multiple pockmarks separated by tens of kilometers. These shifts are presumed to be the result of asymmetrical erosion of the pockmark flanks caused by passing sediment gravity flows. While some pockmarks occur in chains, most are not clustered or randomly spaced but are regularly dispersed within the pockmark field. We hypothesize that intermittent, unconfined sediment gravity flows occurring over at least the last 280,000years are the source of the regionally continuous turbidite deposits and the mechanism that maintained the regularly dispersed pockmarks.
Released May 21, 2024 06:36 EST
2024, Ecology and Evolution (14)
Gabriel M. Barrile, Paul Cross, Cheynne Stewart, Jennifer L. Malmberg, Rhiannon P. Jakopak, Justin Binfet, Kevin Montieth, Brandon Werner, Jessica Jennings-Gaines, JA Merkle
Integrating host movement and pathogen data is a central issue in wildlife disease ecology that will allow for a better understanding of disease transmission. We examined how adult female mule deer (Odocoileus hemionus) responded behaviorally to infection with chronic wasting disease (CWD). We compared movement and habitat use of CWD-infected deer (n = 18) to those that succumbed to starvation (and were CWD-negative by ELISA and IHC;n = 8) and others in which CWD was not detected (n = 111, including animals that survived the duration of the study) using GPS collar data from two distinct populations collared in central Wyoming, USA during 2018–2022. CWD and predation were the leading causes of mortality during our study (32/91 deaths attributed to CWD and 27/91 deaths attributed to predation). Deer infected with CWD moved slower and used lower elevation areas closer to rivers in the months preceding death compared with uninfected deer that did not succumb to starvation. Although CWD-infected deer and those that died of starvation moved at similar speeds during the final months of life, CWD-infected deer used areas closer to streams with less herbaceous biomass than starved deer. These behavioral differences may allow for the development of predictive models of disease status from movement data, which will be useful to supplement field and laboratory diagnostics or when mortalities cannot be quickly retrieved to assess cause-specific mortality. Furthermore, identifying individuals who are sick before predation events could help to assess the extent to which disease mortality is compensatory with predation. Finally, infected animals began to slow down around 4 months prior to death from CWD. Our approach for detecting the timing of infection-induced shifts in movement behavior may be useful in application to other disease systems to better understand the response of wildlife to infectious disease.
Released May 20, 2024 09:51 EST
2024, Rangeland Ecology & Management (95) 56-67
Hailey Wilmer, Daniel B. Ferguson, Maude Dinan, Eric Thacker, Peter B. Adler, Kathryn Bills Walsh, John B. Bradford, Mark Brunson, Justin D. Derner, Emile Elias, Andrew J Felton, Curtis A. Gray, Christina Greene, Mitchel P McClaran, Robert K. Shriver, Mitch Stephenson, Katharine Nash Suding
Rangeland ecosystems, and their managers, face the growing urgency of climate change impacts. Researchers are therefore seeking integrative social-ecological frameworks that can enhance adaptation by managers to these climate change dynamics through tighter linkages among multiple scientific disciplines and manager contexts. Social-ecological framings, including resilience and vulnerability, are popular in such efforts, but their potential to inform meaningful rangeland adaptation science is limited by traditional disciplinary silos. Here, we provide reflective lessons learned from a multidisciplinary Rangelands, Ranching, and Resilience (R3) project on U.S. western rangelands that addressed 1) biophysical science projections of forage production under future climate scenarios, 2) ranchers’ views of resilience using social science methods, and 3) outreach efforts coordinated through extension professionals. Despite the project's initial intentions, human dimensions and ecological researchers largely worked in parallel sub-teams during the project, rather than weaving their expertise together with managers. The R3 project was multidisciplinary, but it provides a case study on lessons learned to suggest how social and ecological researchers can move towards approaches that transcend individual disciplines. Transdisciplinary science and management in rangelands requires more than just conceptual social-ecological frameworks. Additional methodological concepts need to include: 1) relationship building; 2) shared meaning making; and 3) a commitment to continual conversations and learning, or staying with the trouble, following Haraway (2016). If the goal is to address meaningful rangeland adaptation science rather than just produce academic products, researchers, outreach professionals, and rangeland-based communities should address a series of critical troubling questions. In the process of addressing these, deeper engagement among and beyond disciplines will occur as relationship building, shared meaning, and continual conversations and learning facilitate staying with the trouble.
Released May 20, 2024 07:03 EST
2024, Conservation Science and Practice
Ella M. Samuel, Jennifer K. Meineke, Laine E. McCall, Lea B. Selby, Alison C. Foster, Zoe M. Davidson, Carol A. Dawson, Catherine S. Jarnevich, Sarah K. Carter
Public lands are often managed for multiple uses ranging from energy development to rare plant conservation. Habitat models can help land managers assess and mitigate potential effects of projects on rare plants, but it is unclear how models are currently being used. Our goal was to better understand how staff in the Bureau of Land Management currently use habitat models to inform their decisions, and perceived challenges and benefits associated with that use. We first examined litigation documents to determine whether the agency has been challenged on its use of data for rare plants and found no relevant legal challenges. Second, we analyzed model use in National Environmental Policy Act (NEPA) documents and found no clear citations of habitat models. Finally, we conducted interviews with agency staff who analyze potential effects of proposed actions on rare plants in NEPA documents. The primary challenges interviewees faced in using models related to data organization and access, model quality and accuracy, and institutional capacity. Interviewees believed models could be used more to inform decisions and actions to conserve rare plants and rare plant habitat on public lands and recommended improving staff access to models, creating models for additional species, and addressing staffing limitations.
Released May 20, 2024 06:51 EST
2024, Freshwater Biology
Nathaniel P. Hitt, Karli M Rogers, Karmann G. Kessler, Martin Briggs, Jennifer Burlingame Hoyle Fair, Andrew C. Dolloff
- Stream dewatering is expected to become more prevalent due to climate change, and we explored the potential consequences for brook trout (Salvelinus fontinalis)within a temperate forest ecosystem in eastern North America.
- We estimated fish density within stream pools (n = 386) from electrofishing surveys over 10 years (2012–2021) to compare a stream that exhibits episodic dewatering (Paine Run) against a stream of similar size that remains flow-connected (Staunton River) within Shenandoah National Park, Virginia (U.S.A.). Annual surveys encompassed fluvial distances ranging from 2.6 to 4.4 km in each stream.
- Mean annual fish density (fish/pool m2) was not different between streams for juvenile or adult age classes, but spatial variation in density was greater in Paine Run for both age classes of fish. Paine Run also included a greater proportion of unoccupied pools than Staunton River and exhibited stronger spatial autocorrelation in fish density among nearby pools, suggesting dispersal limitation due to surface flow fragmentation.
- Fish density in pools increased during years with low summer precipitation, and this effect was observed in both streams but was stronger in Paine Run than Staunton River, further indicating the importance of fish movement into pools in response to low-flow thresholds.
- Our results indicate the importance of pools as ecological refuges during low-flow conditions and that episodic dewatering may affect extirpation risks for brook trout by sequestering more fish into fewer areas. Our findings also highlight the importance of hydrological variation within stream networks because downstream river gages could not predict the observed spatial heterogeneity in fish density or pool occupancy.
Released May 20, 2024 06:47 EST
2024, Proceedings of the National Academy of Sciences (121)
Joshua C. Koch, Craig T. Connolly, Carson Baughman, Marisa Repasch, Heather Best, Andrew Hunt
Water is a limited resource in Arctic watersheds with continuous permafrost because freezing conditions in winter and the impermeability of permafrost limit storage and connectivity between surface water and deep groundwater. However, groundwater can still be an important source of surface water in such settings, feeding springs and large aufeis fields that are abundant in cold regions and generating runoff when precipitation is rare. Whether groundwater is sourced from suprapermafrost taliks or deeper regional aquifers will impact water availability as the Arctic continues to warm and thaw. Previous research is ambiguous about the role of deep groundwater, leading to uncertainty regarding Arctic water availability and changing water resources. We analyzed chemistry and residence times of spring, stream, and river waters in the continuous permafrost zone of Alaska, spanning the mountains to the coastal plain. Water chemistry and age tracers show that surface waters are predominately sourced from recent precipitation and have short (<50 y) subsurface residence times. Remote sensing indicates trends in the areal extent of aufeis over the last 37 y, and correlations between aufeis extent and previous year summer temperature. Together, these data indicate that surface waters in continuous permafrost regions may be impacted by short flow paths and shallow suprapermafrost aquifers that are highly sensitive to climatic and hydrologic change over annual timescales. Despite the lack of connection to regional aquifers, continued warming and permafrost thaw may promote deepening of the shallow subsurface aquifers and creation of shallow taliks, providing some resilience to Arctic freshwater ecosystems.
Released May 20, 2024 06:37 EST
2024, Communications Earth and Environment (5)
Jonathan A. O'Donnell, Michael P. Carey, Joshua C. Koch, Carson Baughman, Kenneth Hill, Christian E. Zimmerman, Patrick F. Sullivan, Roman J. Dial, Timothy J. Lyons, David J. Cooper, Brett A. Poulin
Climate change in the Arctic is altering watershed hydrologic processes and biogeochemistry. Here, we present an emergent threat to Arctic watersheds based on observations from 75 streams in Alaska’s Brooks Range that recently turned orange, reflecting increased loading of iron and toxic metals. Using remote sensing, we constrain the timing of stream discoloration to the last 10 years, a period of rapid warming and snowfall, suggesting impairment is likely due to permafrost thaw. Thawing permafrost can foster chemical weathering of minerals, microbial reduction of soil iron, and groundwater transport of metals to streams. Compared to clear reference streams, orange streams have lower pH, higher turbidity, and higher sulfate, iron, and trace metal concentrations, supporting sulfide mineral weathering as a primary mobilization process. Stream discoloration was associated with dramatic declines in macroinvertebrate diversity and fish abundance. These findings have considerable implications for drinking water supplies and subsistence fisheries in rural Alaska.
Released May 18, 2024 11:31 EST
2024, Journal of Petrology
Marie K. Takach, Frank J. III Tepley, Christopher Harpel, Rigoberto Aguilar, Marco Rivera
We investigate ten of the most recent tephra-fall deposits emplaced between ≤21–2 ka from the Pacheco stage of Misti volcano, Peru, to elucidate magma dynamics and explosive eruption triggers related to magma storage, recharge, and remobilization. Whole-rock, glass, and mineral textures and compositions indicate the presence of broadly felsic, intermediate, and mafic magmas in a chemically and thermally stratified magma storage system (Zones 1–3) that interact to differing extents prior to eruption. Intermediate magmas are defined by plagioclase + amphibole + two-pyroxenes + Fe-Ti oxides and phase equilibria indicate they formed at ~300–600 MPa and ~950–1000 °C. Intermediate magmas dominate the Pacheco stage and either erupted alone as hybridized magmas or mingled with minor volumes of cool felsic magmas (~800 °C) in which only plagioclase + Fe-Ti oxides are stable. Felsic magmas do not exclusively comprise any tephra-fall deposit emplaced during the Pacheco stage but were remobilized by recharge and mixing with intermediate magmas in order to erupt. Furthermore, felsic-hosted amphibole cognate to the intermediate magmas are reacted despite the felsic magmas being water saturated, which suggests they are staged above the amphibole stability limit (≤200 MPa). The cryptic presence of mafic magmas is indicated by high-An plagioclase cores (An74–88), rare anhedral olivine (Fo77–80), and possibly high Mg# augite and amphibole (up to Mg# 84 and 77, respectively). The dearth of basalt to basaltic andesite melts recorded in erupted glasses and exclusivity of high-An plagioclase to crystal cores signals mafic magmas are staged deeper in the crust than the intermediate magmas. Periodic interactions between these magmas tracked via glass compositions and crystal exchange reveal an alternation between the production of mingled magmas and their eruption shortly after a recharge event, followed by a period of hom*ogenization and eruption of hybridized magmas. As such, we identify magma recharge as a key mechanism by which half of the explosive eruptions were triggered in the Pacheco stage. A >100 °C increase in Misti’s fumarole temperatures from 1967 to 2018 coincident with changes in fumarolic gas composition is consistent with degassing of a mafic recharge magma, signaling that Misti could produce similar explosive eruptions in the future.
Released May 18, 2024 06:42 EST
2024, Earth Surface Processes and Landforms
Anna Könz, Jacob Hirschberg, Brian McArdell, Benjamin B. Mirus, Tjalling de Haas, Perry Bartelt, Peter Molnar
Debris-flow volumes can increase along their flow path by entraining sediment stored in the channel bed and banks, thus also increasing hazard potential. Theoretical considerations, laboratory experiments and field investigations all indicate that the saturation conditions of the sediment along the flow path can greatly influence the amount of sediment entrained. However, this process is usually not considered for practical applications. This study aims to close this gap by combining runout and hydrological models into a predictive framework that is calibrated and tested using unique observations of sediment erosion and debris-flow properties available at a Swiss debris-flow observation station (Illgraben). To this end, hourly water input to the erodible channel is predicted using a simple, process-based hydrological model, and the resulting water saturation level in the upper sediment layer of the channel is modelled based on a Hortonian infiltration concept. Debris-flow entrainment is then predicted using the RAMMS debris-flow runout model. We find a strong correlation between the modelled saturation level of the sediment on the flow path and the channel-bed erodibility for single-surge debris-flow events with distinct fronts, indicating that the modelled water content is a good predictor for erosion simulated in RAMMS. Debris-flow properties with more complex flow behaviour (e.g., multiple surges or roll waves) are not as well predicted using this procedure, indicating that more physically complete models are necessary. Finally, we demonstrate how this modelling framework can be used for climate change impact assessment and show that earlier snowmelt may shift the peak of the debris-flow season to earlier in the year. Our novel modelling framework provides a plausible approach to reproduce saturation-dependent entrainment and thus better constrain event volumes for current and future hazard assessment.
Released May 17, 2024 15:00 EST
2024, Scientific Investigations Report 2023-5135
Mackenzie K. Keith, J. Rose Wallick, Liam N. Schenk, Laurel E. Stratton Garvin, Gabriel W. Gordon, Heather M. Bragg
Chapter A. Introduction
Fall Creek Dam impounds Fall Creek Lake, a 10-kilometer-long reservoir in western Oregon and is operated by the U.S. Army Corps of Engineers (USACE) primarily for flood-risk management (or flood control) in late autumn through early spring months, as well as for water quality, irrigation, recreation, and habitat in late spring through early autumn. Since 2011 (water year [WY] 2012), Fall Creek Lake has been temporarily drawn down each year to facilitate downstream passage of juvenile spring Chinook salmon (Oncorhynchus tshawytscha) through the 55-meter (m) high dam. This annual dam operation is temporary, typically lasting about 1–2 weeks from WY 2012 through 2020 (drawdown operations in WY 2022–24 have increased to more than 6 weeks). Drawdown of the reservoir results in lake levels being lowered to the elevation near the historical, pre-dam streambed. The annual streambed drawdowns of WY 2012–18 have improved fish passage and led the USACE to formally adopt streambed drawdowns as part of annual operations at Fall Creek Dam. However, temporarily lowering the lake to streambed creates free-flowing conditions in the reservoir that result in the erosion and episodic export of predominantly sand and finer-grained sediments (less than 2 millimeters [mm]) to the lower gravel-bed reaches of Fall Creek and the Middle Fork Willamette River. The introduction of large volumes of sand and finer-grain sediment into the dam-regulated reaches downstream from Fall Creek Dam prompted questions about the geomorphic responses to annual streambed drawdowns within Fall Creek Lake and downstream reaches along Fall Creek and the Middle Fork Willamette River. The U.S. Geological Survey (USGS) in partnership with USACE initiated a comprehensive geomorphic and sediment transport investigation to assess the coupled processes of reservoir erosion, sediment evacuation from Fall Creek Lake, and patterns of sediment transport and deposition in reaches downstream from the Fall Creek Dam that have resulted from annual streambed drawdowns.
The purpose of this report is to systematically describe the processes of sediment erosion, transport, and deposition at Fall Creek Lake and geomorphic interactions between reaches upstream and downstream from Fall Creek Dam that relate to dam operations. Specifically, this report focuses on evaluating geomorphic responses to streambed drawdowns from WY 2012 through 2018 and placing drawdown-induced geomorphic responses within the broader context of physiographic and historical conditions and dam operations of Fall Creek and Middle Fork Willamette Rivers. Key objectives for this study were to characterize changes in reservoir morphology and substrate at Fall Creek Lake, describe the character and temporal pattern of sediment transport downstream from Fall Creek Dam, characterize geomorphic changes in channel reaches downstream from the Fall Creek Dam, and relate these data to the annual streambed drawdowns of WY 2012–18. This study uses multiple independent monitoring and measurement approaches to assess site, reach, and river-scale geomorphic responses to drawdowns to inform dam and reservoir management. Patterns and processes of reservoir evolution were assessed with geomorphic mapping and volumetric analyses of topography through comparison of multiple digital surface models (DSMs). Just downstream from Fall Creek Dam, analyses of sediment export from the reservoir focused on suspended sediment but also incorporated bedload analyses to assess sediment sizes. Geomorphic assessments downstream from the dam used reach-scale and site-scale approaches to document changes in channel morphology and substrate, including site measurements of sand and finer-grained sediment deposition and in-channel bed-material, volumetric change analyses from comparison of digital elevation models (DEMs), and repeat geomorphic mapping. Findings from this study inform river management and dam operations by providing an understanding of (1) coupled upstream-downstream geomorphic responses to the Fall Creek Lake streambed drawdowns, (2) geomorphic responses of Fall Creek Lake streambed drawdowns in comparison to drawdowns at other large dams, (3) controls on reservoir erosion and downstream geomorphic responses, and (4) implications for future hydrogeomorphic changes that may result from continued drawdowns and monitoring activities to assess those changes.
Chapter B. Reservoir Morphology and Evolution Related to Dam Operations at Fall Creek Lake
To understand the volume and distribution of sediment accumulation in Fall Creek Lake since dam closure in 1965, decadal-scale sedimentation patterns (spanning approximately 1965–2016) are evaluated using a combination of storage curve analyses and geomorphic mapping. Short-term (drawdown event-scale) patterns of erosion, sedimentation, and sediment export downstream are evaluated using a combination of geomorphic mapping and change detection analyses that quantify the distribution and total volume of sediment erosion and deposition within Fall Creek Lake.
Geomorphic mapping of reservoir topography and analyses of historical datasets reveals four categories of landforms and sediment processes within Fall Creek Lake related to lake level operations:
- lacustrine sedimentation expressed in the reservoir floor,
- fluvial erosion and deposition within historical stream channels during streambed drawdowns,
- channel-like features created by erosion within the reservoir floor during streambed drawdowns, and
- erosion on reservoir hillslopes.
Where the reservoir floor is mapped for this study as pelagic (deep water), deposition up to 3 meters (m) thick by lacustrine processes and burial of pre-dam topography with deposits thinning toward the edges of the valley floor and upstream areas of reservoir are observed. Despite over 50 years of sediment accumulation since dam construction, the main stream channels of Fall and Winberry Creeks (or reservoir thalwegs) through the reservoir are well defined, though their distinct morphology is likely influenced by a long history of recurring historical drawdowns to or near streambed since dam construction. Unregulated streamflow and sediment transport through the reservoir primarily are confined to these channels during the streambed drawdown periods. Erosional channel-like features created by drawdowns are carved through underlying, unconsolidated reservoir floor sediments and are most prominent in the lower reservoir below minimum conservation pool (the low pool elevation during winter flood season); sediment generated from the formation of these drawdown channels is more likely to be transported through and out of the reservoir than sediment deposits along the reservoir hillslopes at the valley margins that are separated from main channels by areas of low-gradient reservoir floor. Morphologic changes in the lower reservoir topography between January 2012 and November 2016 indicate overall net erosion of about 129,500 cubic meters (m3). The most prominent geomorphic changes occurred along the main channels of Fall and Winberry Creeks near the Fall Creek Dam where incision, lateral migration, and slumping banks resulted in vertical and lateral adjustments to channel position, whereas most changes fell below the detectable limit on higher-elevation reservoir floor surfaces except where erosion occurred along features mapped as drawdown channels.
Chapter C. Sediment Delivery from Fall Creek Lake and Transport through Downstream Reaches
USGS implemented a sediment monitoring program in WY 2013–18 to evaluate the quantity and character of reservoir sediment exported from Fall Creek Lake during streambed drawdowns. Turbidity and suspended sediments were monitored annually autumn through spring to span the WY 2013–18 streambed drawdowns; however, unequal monitoring timeframes each year reduced the ability to compare results and factors affecting sediment export from the reservoir difficult between years. These data were originally measured to develop regressions and compute suspended-sediment loads (SSL). Bedload sediment monitoring from a cableway at the Fall Creek streamgage was completed in the autumn-winter of WY 2013 and 2017. The limited number of samples and presumed variability in sediment supply from the reservoir precluded construction of streamflow and bedload discharge relations to compute more than instantaneous bedload.
Sand and finer-grained silts and clays were transported from the reservoir in suspension, though some coarser grains (up to 32 mm) were also mobilized and transported downstream from the dam as bedload. Observations of increased sediment transport downstream from Fall Creek Dam coincided with lake levels approaching about 3 m (10 feet [ft] or elevation 690 ft) above the streambed regulating outlets. Suspended-sediment loads computed for the full monitoring periods WY 2013–18 at the Fall Creek streamgage, located 1.4 kilometers (km) downstream from Fall Creek Dam, range from 54,700 metric tons (t) in WY 2013 to 13,900 t in WY 2018. Although the total annual SSL varied from year to year, the overall seasonal patterns of suspended sediment transport throughout each year were similar during monitoring in WY 2013-18. Suspended-sediment loads were low prior to the drawdown, then increased rapidly as lake levels lowered and approached the streambed. In the weeks following the drawdown period, as pool levels were increased, SSL remained slightly elevated above pre-drawdown levels but generally declined through the following winter and spring except during streamflow-driven pulses of suspended-sediment transport. WY 2013 had the greatest total computed SSL for each streambed drawdown and partial-year monitoring period. SSL computed for the partial-year period have generally decreased since WY 2013 and have varied by about 6,800 t with the exception of WY 2014. WY 2014 SSL reflects anomalously low sediment export due to low streamflows and freezing conditions that stabilized reservoir floor deposits. Bedload measurements in the short 1.4-km reach between Fall Creek Dam and the Fall Creek streamgage showed an inverse correlation between bedload transport rates and discharge, which probably reflects diminishing supply of coarse-sized sediment. Sand was more abundant (60–100 percent) than gravel in bedload samples confirming sand and finer-grained sediment dominated sediment evacuated from the reservoir during streambed drawdowns at Fall Creek Lake.
Chapter D. Geomorphic Responses to Fall Creek Lake Streambed Drawdowns Downstream from Fall Creek Dam
In the days, weeks, and months following streambed drawdown operations at Fall Creek Dam through WY 2018, sites downstream from the dam displayed a variety of geomorphic responses to reservoir sediment delivery within the main channel and overbank areas. Evaluation of streambed elevations at two streamgages located 1.4 km downstream from the dam on Fall Creek and 16.3 km downstream from the dam on the Middle Fork Willamette River indicated the effects of drawdown sediment on bed elevations were modest and transient. Repeat particle size measurements (October 2015 and September 2016) at five sites along Fall Creek and the Middle Fork Willamette River showed similar grain-sized distributions that do not reveal substantial deposition of fine-grained sediment related to the WY 2016 streambed drawdown. Altogether, these findings indicate that transport capacity in the main, low-flow channels of Fall Creek and Middle Fork Willamette River during WY 2012–18 was sufficient to mobilize and evacuate reservoir sediments from streambed drawdowns or other bank material and tributary sources. However, other monitoring for this study indicate low-velocity zones in off-channel areas are prime locations for sand and finer-grain sediment deposition. Patterns of overbank sediment accumulation indicate that the magnitude and timing of overbank deposition on bars and low-elevation floodplain varies with proximity to the dam, geomorphic setting, streamflows, and other factors. Sand and finer-grained reservoir sediments carried as suspended-sediment load in the reaches downstream from Fall Creek Dam were deposited in overbank areas as observed with clay-horizon markers during WY 2016–17. Overbank deposition quantified with Geomorphic Change Detection (GCD) software evaluated landform-scale patterns of erosion and deposition using repeat light detection and ranging (lidar) surveys at two sites in the Upper Fall Creek reach and one site in the Jasper reach for 3 years (2012–15) and one site in the Clearwater reach for 6 years (2009–15). Deposition thickness and spatial patterns from the GCD analysis were variable; some sites had dispersed but measurable deposition while at others, deposition was highly localized and exceeded 1 m in depth. Patterns of overbank deposition illustrate interactions among bar morphology, local hydraulics, and suspended-sediment transport dynamics that can create patches of highly localized deposition. The measured deposition at the two Fall Creek GCD sites likely resulted from reservoir sediments released from Fall Creek Lake during streambed drawdowns in WY 2016 and 2017 because the limited sediment inputs from bank material (geomorphically laterally stable reach) or tributaries (no significant tributaries) provided few other sediment sources. On the Middle Fork Willamette River, observed patterns of overbank deposition could reflect sediment sourced from upstream tributaries, bank erosion, or Fall Creek Lake streambed drawdown operations.
Despite the introduction of several thousand tons of reservoir sediment delivered from the Fall Creek Lake streambed drawdowns to below-dam river corridors, reach-scale mapping of channel features downstream from Fall Creek Dam shows minimal evidence of changes in channel planform or landforms that can be attributed to a drawdowns in WY 2012–16. On Upper Fall Creek reach, widespread increases in gravel bars or other in-channel sediment did not result from the five streambed drawdowns. The main changes attributable to sediment releases from Fall Creek Lake were localized increases in vegetated bar area, particularly on channel margin areas where sand and finer-grain sediment was deposited and rapidly colonized by vegetation. The area of mapped secondary water features decreased between 2005 and 2016, but that may be due to lower discharges depicted in the 2016 aerial photographs and less mapped area of inundation. Primary changes along the Lower Fall Creek reach include a 6.4 percent decrease in area of secondary water features between 2011 and 2016, and a nearly twofold increase in the area of unvegetated bars. Immediately downstream from the Fall Creek confluence, there were negligible changes in the location and areas of vegetated bars and the main wetted channel between 2005 and 2016, and local increases in bar area cannot be attributed solely to deposition of reservoir sediments from Fall Creek Lake because (1) areas along the Middle Fork Willamette River just upstream from the Fall Creek confluence display similar type and magnitude of changes and (2) some of the increases at the confluence area pre-date the drawdowns. The cumulative effect of sediment releases from Fall Creek Lake streambed drawdowns from WY 2012 to 2016 on downstream channel planform and landforms are modest compared to the river-scale transformations and planform changes that occurred in the decades following dam construction.
Chapter E. Discussion of Geomorphic Responses of Fall Creek and Middle Fork Willamette River to Streambed Drawdowns at Fall Creek Lake
Multiple aspects of Fall Creek Dam infrastructure and operations exert first-order controls on the magnitudes of reservoir erosion that occur during the streambed drawdowns and ultimately determine the sediment delivery to downstream reaches. Key aspects of the dam and its operations that are most relevant to assessing geomorphic responses to streambed drawdowns include the (1) dam infrastructure, including configuration and size of regulating outlets and their proximity to the streambed which dictates the capacity and competence of the river to deliver sediment to downstream reaches and mode of sediment transport as suspended-sediment load or bedload; (2) frequency of historical drawdowns and long-term, year-round dam operations and lake level management, which partly dictate reservoir morphology and locations and magnitudes of readily erodible materials; (3) dam operations and hydroclimatic conditions during the streambed drawdown (including length of the drawdown and streamflows entering the reservoir), which directly control the timing, duration and magnitude of reservoir erosion and sediment evacuation; and (4) dam operations following the streambed drawdown operation that regulate streamflows (and thereby sediment transport conditions) downstream of Fall Creek Dam which primarily reflect interactions between hydroclimatic conditions and flood control operations.
Patterns of sediment erosion and evacuation observed in this study at Fall Creek Lake from WY 2012–18 suggest that reservoir erosion during annual streambed drawdowns may remain similar or decrease in future years assuming (1) annual streambed drawdown operations are implemented in similar manner as the WY 2012–18 drawdowns (in terms of duration, late autumn or early winter implementation, rate of pool-level lowering to reach streambed, and other factors), (2) streambed drawdowns coincide with similar conditions as were observed WY 2012–18 (similar sediment yield into reservoir, low reservoir inflows, limited precipitation, moderate air temperature), and (3) no major geomorphic changes in the main reservoir channels of Fall and Winberry Creeks occur (for example, channel avulsion). Under such conditions, it is hypothesized that the stream channel within the reservoir would achieve a quasi-equilibrium state with respect to annual influx and export of sediment and aided by the substantial amount of in-channel bedrock, will remain laterally stable without erosion across reservoir deposits.
Patterns of sediment transport measured at the Fall Creek streamgage downstream from Fall Creek Dam provide insight into the potential effects of future streambed drawdowns at Fall Creek Lake. Analyses of suspended sediment measured in WY 2013–18 show a major reduction in suspended-sediment loads between WY 2013 and later years, indicating streamflows transporting sediment through the reservoir to downstream reaches during streambed drawdowns have become supply limited. The 6-year suspended-sediment monitoring and sampling program is insufficient to make predictions about future sediment transport conditions because of uneven monitoring periods and varying controls on reservoir sediment erosion. It is likely that future suspended-sediment loads will be variable but similar to those observed in WY 2015–18 if operational, climatic, and geomorphological factors remain similar to those monitored WY 2015–18. Suspended-sediment loads downstream from Fall Creek Lake will likely remain highest when regulating outlets are fully open and Fall Creek is free flowing with the reservoir fully drained with little to no residual pool. Over time, it is possible that the suspended-sediment loads would reflect mobilization of reservoir sediment deposited in the previous year rather than erosion of sediment deposited years or decades earlier. Bedload is likely to remain a small fraction of the total sediment load evacuated from the reservoir and is relatively modest compared with pre-dam bedload transport rates because most coarse sediment remains trapped by the dam.
If sediment releases from Fall Creek Lake and ensuing streamflow conditions follow a similar pattern in the future as was assessed in this study spanning WY 2012–18, near-term geomorphic adjustments downstream of the dam are expected to be modest. Barring major operational, climatic, and geomorphological changes, local site-scale deposition on bars, overbank areas, or off-channel features that persists several months after the streambed drawdown will likely continue to be highly variable, ranging from negligible to several centimeters of deposition. At the landform-scale, low velocity areas nearest to Fall Creek Dam will likely continue to undergo rapid deposition immediately during and after a streambed drawdown event, similar to patterns observed for WY 2012–18. Some of the sediment entering these off-channel features and margin areas may be temporarily stored, then later remobilized and dispersed farther downstream. But if newly deposited sediment persists through the following spring, there is a greater likelihood that local vegetation will establish, reinforce deposited material, and trap sediment during later drawdowns. The reach-scale geomorphic changes may become more apparent if (1) streambed drawdowns continued for several decades, and geomorphic changes were measured at decadal scales or (2) the amount of sediment introduced to downstream reaches substantially increased and (or) sediment transport capacity decreased. The continued streamflow regulation of Fall Creek Dam after sediment releases provides an opportunity to strategically manage streamflows during and after the streambed drawdowns to minimize downstream sediment impacts and ensure other operational thresholds are satisfied.
This study provides a comprehensive foundation of datasets and geomorphic analyses to inform dam operations at Fall Creek Lake, monitor sediment transport downstream, and consider operational schemes for future drawdowns. The datasets from this study also provide baselines of sediment transport and geomorphic conditions to assess future changes in reservoir and downstream environments. Future monitoring could be tailored to address specific questions regarding the long-term geomorphic effects of streambed drawdowns on fluvial habitats, flood hazards, cultural resources, or downstream water quality. Future monitoring activities could focus on the relevant geomorphic processes and spatial domains within the three categories used for this study: (1) reservoir erosion and net sediment evacuation, (2) sediment delivery to downstream reaches, including magnitude and temporal pattern of sediment transport, and (3) geomorphic responses of downstream reaches to sediment delivery. Specifically, high priority future monitoring activities could include:
- Repeat topographic or photographic surveys in the reservoir to characterize changes occurring within individual drawdowns, to quantify sediment export, to determine temporal changes in reservoir storage, and to identify locations of erosion and deposition.
- Continuous, year-round turbidity monitoring supplemented with suspended-sediment measurements at a streamflow-gaging station immediately downstream from the dam to quantify sediment export.
- Repeat geomorphic monitoring, mapping, or modeling in downstream reaches to track changes in channel and over bank features using a combination of site- and reach-scale monitoring approaches. This could support assessments of sediment deposition and ensuing vegetation encroachment on flood hazards and habitats and examine how sediment transport and depositional processes may be affected by different sediment supply, streamflow, or dam management scenarios.
Released May 17, 2024 11:00 EST
2024, Fact Sheet 2024-3009
Cayla R. Morningstar, Patrick M. Kočovský, Michael E. Colvin, Timothy D. Counihan, Wesley M. Daniel, Peter C. Esselman, Cathy A. Richter, Adam Sepulveda, Diane L. Waller
The U.S. Geological Survey (USGS) delivers high-quality data, technologies, and decision-support tools to help managers both reduce existing populations and control the spread of dreissenid mussels. The USGS researches ecology, biology, risk assessment, and early detection and rapid response methods; provides decision support; and develops and tests control measures.
Released May 17, 2024 08:03 EST
2024, Data Report 1194
Scarlett L. Howell, Barbara E. Kus
We surveyed for Southwestern Willow Flycatchers (Empidonax traillii extimus; flycatcher) along the upper San Luis Rey River near Lake Henshaw in Santa Ysabel, California, in 2023. Surveys were completed at four locations: three downstream from Lake Henshaw, where surveys previously occurred from 2015 to 2022 (Rey River Ranch [RRR], Cleveland National Forest [CNF], Vista Irrigation District [VID]), and one at VID Lake Henshaw (VLH) that has been surveyed annually since 2018. There were a minimum of 74 territorial flycatchers detected at 1 location (VLH), and 12 transient flycatchers of unknown subspecies detected at 2 locations (CNF and VLH). At VLH, we detected a minimum of 31 males, 40 females, and 3 flycatchers of unknown sex. In total, 51 territories were established, containing 40 pairs and 11 flycatchers of undetermined breeding status (8 males and 3 flycatchers of unknown sex). Of the 40 pairs, 9–11 pairs were monogamous (1 male and 1 female), and 29–31 pairs were polygynous (1 male paired with more than 1 female). For the first time since annual surveys began in 2015, no territorial flycatchers were detected downstream from Lake Henshaw. Brown-headed cowbirds (Molothrus ater; cowbird) were detected at all four survey locations. No banded flycatchers were detected during surveys.
Flycatchers used three habitat types in the survey area: (1) mixed willow riparian, (2) willow-cottonwood, and (3) oak-sycamore. Of the flycatcher locations, 86 percent were in habitat characterized as mixed willow riparian, and 95 percent were in habitat with greater than 95-percent native plant cover. Exotic vegetation was not prevalent in the survey area.
There were five nests incidentally located during surveys: one failed, one was seen with eggs on the last visit, and the outcome of the remaining three nests was unknown. One of these nests was parasitized by cowbirds, and a second nest was suspected to contain a cowbird nestling. Adult flycatchers in two territories were observed feeding cowbird fledglings. No juvenile flycatchers were detected during surveys.
Released May 16, 2024 06:48 EST
2024, Integrated Environmental Assessment and Management
Jonathan M. Petali, Erin L. Pulster, Chris McCarthy, Heidi M. Pickard, lsie M. Sunderland, Jacqueline T. Bangma, Anna R. Robuck, Courtney Carignan, Kathryn A. Crawford, Megan E. Romano, Rainer Lohmann, Katherine E. von Stackelberg
Federal, state, tribal, or local entities in the United States issue fish consumption advisories (FCAs) as guidance for safer consumption of locally caught fish containing contaminants. Fish consumption advisories have been developed for commonly detected compounds such as mercury and polychlorinated biphenyls. The existing national guidance does not specifically address the unique challenges associated with bioaccumulation and consumption risk related to per- and polyfluoroalkyl substances (PFAS). As a result, several states have derived their own PFAS-related consumption guidelines, many of which focus on one frequently detected PFAS, known as perfluorooctane sulfonic acid (PFOS). However, there can be significant variation between tissue concentrations or trigger concentrations (TCs) of PFOS that support the individual state-issued FCAs. This variation in TCs can create challenges for risk assessors and risk communicators in their efforts to protect public health. The objective of this article is to review existing challenges, knowledge gaps, and needs related to issuing PFAS-related FCAs and to provide key considerations for the development of protective fish consumption guidance. The current state of the science and variability in FCA derivation, considerations for sampling and analytical methodologies, risk management, risk communication, and policy challenges are discussed. How to best address PFAS mixtures in the development of FCAs, in risk assessment, and establishment of effect thresholds remains a major challenge, as well as a source of uncertainty and scrutiny. This includes developments better elucidating toxicity factors, exposures to PFAS mixtures, community fish consumption behaviors, and evolving technology and analytical instrumentation, methods, and the associated detection limits. Given the evolving science and public interests informing PFAS-related FCAs, continued review and revision of FCA approaches and best practices are vital. Nonetheless, consistent, widely applicable, PFAS-specific approaches informing methods, critical concentration thresholds, and priority compounds may assist practitioners in PFAS-related FCA development and possibly reduce variability between states and jurisdictions.Integr Environ Assess Manag2024;00:1–20. © 2024 SETAC
Released May 15, 2024 12:45 EST
2024, Circular 1517
Vivian B. Hutchison, Thomas E. Burley, Kyle W. Blasch, Paul E. Exter, Gregory L. Gunther, Aaron J. Shipman, Courtney M. Kelley, Cheryl A. Morris
The U.S. Geological Survey (USGS) has long recognized the strategic importance and value of well-managed data assets as an integral component of scientific integrity and foundational to the advancement of scientific research, decision making, and public safety. The USGS investment in the science lifecycle, including collection of unbiased data assets, interpretation, peer review, interpretive publications, and data release, ultimately contributes to the transparency and availability of science. Foundational Government directives and laws, such as the Foundations for Evidence-Based Policymaking Act of 2018 (Public Law 115–435, 132 Stat. 5529) as well as Executive Order 13642, “Making Open and Machine Readable the New Default for Government Information,” provide a framework for addressing strategic data management. The USGS Data Strategy builds on that framework by outlining high-level goals and objectives that serve as a long-term, decadal guide toward achieving a broad, data-focused vision.
Benefits of the USGS Data Strategy are many. The USGS will contribute to open science by increasing efficiencies in the consistent management of valuable data assets; driving innovation that results in modernized capabilities to ensure data are analysis ready; increasing data skills across the Bureau to enhance workforce data literacy; broadening capacity to understand and address needs of stakeholders; and measuring progress in producing findable, accessible, interoperable, and reusable (FAIR) data products.
The major goals and objectives of the USGS Data Strategy promote maximizing the utility of USGS data based on stakeholder needs, promoting data innovation, coordinating common data practices, modernizing our USGS enterprise data architecture, and enhancing our data-centric culture. The goals and objectives in the strategy align with other Bureau strategic plans, guidance, and directives from the Department of the Interior and the Federal Government. This strategy is a key component to strengthen the Bureau’s data ecosystem to ensure a relevant, long-term capacity that supports internal needs and achieves its scientific mission in the most efficient and effective manner.
Released May 15, 2024 11:45 EST
2024, Limnology and Oceanography
Jingwen Zhang, Moriaki Yasuhara, Chih-Lin Wei, Skye Yunshu Tian, Kyawt K. T. Aye, Laura Gemery, Thomas M. Cronin, Peter Frenzel, David J. Horne
Eye loss has been a long-standing interest in evolutionary biology. Many organisms that inhabit environments without light penetration, for example the deep sea, exhibit eye loss and thus become blind. However, water-depth distribution of eyes in marine organisms is poorly understood. Ostracods are widely distributed crustaceans, and many sighted marine ostracods have eye tubercles (lenses) on their shells. Since eye tubercles are visible on the shells illustrated in much literature, it is easy to determine their presence or absence via a literature survey. Here, we used a large Arctic-wide ostracod census dataset (Arctic Ostracode Database) to calculate the eye index (the percentage of species with eyes), and compare them with water depth and light availability. As water depth increases, eye index values decrease and become constantly zero in water deeper than 1000 m. Similar decline of sighted species with increasing depth is also known in isopods and amphipods, suggesting that it may be common in other crustaceans and perhaps in deep-sea organisms in general. We also show that eye index values increase as light availability increases. This study is the first to quantify how distributions of sighted and blind species change with light availability, giving baseline information on vision in the deep sea.
Released May 15, 2024 07:05 EST
2024, Circular 1512
Mark H. Sherfy, editor(s)
The mission of Northern Prairie Wildlife Research Center is to provide scientific information needed to conserve and manage the Nation’s natural capital for current and future generations, with an emphasis on migratory birds, Department of the Interior trust resources, and ecosystems of the Nation’s interior. This report provides an overview of the studies conducted at Northern Prairie during fiscal years 2021–23 in pursuit of this mission. Studies are organized under a framework developed by the U.S. Geological Survey Ecosystems Mission Area, identifying primary and secondary alignment with focal areas of research, and summarizing recent scientific products resulting from these studies. Partnerships with Federal, State, and non-Governmental organizations are essential to a robust program of applied ecological research, and we thank our many collaborators and colleagues whose contributions made this work possible.
Released May 15, 2024 06:58 EST
2024, Report
Eben H. Paxton, P. Marcos Gorresen, Paul M. Cryan, Megan Parker
The yǻyaguak (Mariana swiftlet, Aerodramus bartschi) is an endangered cave-roosting species native to Guam and southern Mariana Islands, Micronesia. The population on Guam has declined substantially over the last half century, likely due to the introduction of the brown treesnake (Boiga irregularis), but other factors have been proposed including habitat loss, pesticides, reduced food resources, and powerful storms. On May 24–25, 2023, Guam was hit by the category-4 Typhoon Mawar, which brought wide-spread destruction to the island. Approximately 6 weeks prior to the typhoon in April 2023, we conducted surveys of the three known colonies of yǻyaguak at Mahlac, Maemong, and Fachi caves. This survey provided a baseline population estimate prior to Typhoon Mawar’s landfall. In July 2023, we resurveyed the caves to estimate colony size and assess whether the cave colonies experienced significant declines in the immediate aftermath of the storm. In November 2023, we conducted our regularly scheduled biannual surveys which provided a longer-term assessment of potential impacts from the typhoon. Our counts indicated that in the immediate aftermath (~6 weeks) there was a 7–8% reduction in size of colonies compared to the April 2023 counts, but in November there were larger, 19–35% reductions in the cave colonies from pre-Mawar surveys. These results suggest that the long-term effects of the storm were more detrimental to the yǻyaguak populations than the immediate impacts if these colony size reductions are a result of the storm. Continued monitoring of the yǻyaguak cave colonies will allow for documenting the pace of recovery from the storm.
Released May 15, 2024 06:37 EST
2024, Joule (8) 1208-1233
Anthony Ku, Elisa Alonso, Rod Eggert, Thomas Graedel, Komal Habib, Alessa Hool, Toru Muta, Dieuwertje Schrijvers, Luic Tercero, Tatiana Vakhitova, Constanze Veeh
Critical materials are resources that are vulnerable to supply disruptions, where those disruptions can have significant adverse impacts on society. In the coming years, materials supply risks associated with the energy transition and geopolitics are likely to intensify and new risks are expected to emerge. This perspective identifies three “Grand Challenges” that represent frontier areas for critical materials research and highlights some promising new directions for each area: (1) extending visibility downstream to value-added materials beyond elemental forms; (2) quantifying the risks associated with market dynamics; and (3) developing tools to inform policy interventions. Emerging digital capabilities have the potential to play a significant role addressing long-standing limitations in data quality and access to unlock progress on these challenges. Progress in these areas can equip decision-makers across industry, government, and finance with tools to understand the complexity and uncertainty introduced by these real-world challenges.
Released May 14, 2024 14:30 EST
2024, Scientific Investigations Report 2024-5040
W. Barclay Shoemaker, Qinglong Wu
In 2012, a platform at the approximate center of Lake Okeechobee in central Florida was instrumented to continuously measure evaporation with the Bowen-ratio energy-budget method as part of a long-term partnership between the South Florida Water Management District and the U.S. Geological Survey. The primary goal for the study was to quantify daily rates of open-water evaporation. A secondary goal was to assess differences in evaporation rates among alternate methods and determine if instrumentation and operational expenses associated with the Bowen-ratio method could be reduced.
Mean annual evaporation from Lake Okeechobee for 2013–16 was about 1,825 millimeters per year. Annual evaporation from 2013 to 2016 was 1,760, 1,840, 1,810, and 1,890 millimeters per year, respectively. These evaporation rates are among the highest rates observed in Florida based on scientifically vetted methods such as evaporation pans, lysimeters, eddy-covariance, or Bowen-ratio methods. The high evaporation rates are largely a result of frequent clear-sky conditions over the interior of Lake Okeechobee, which allows solar radiation to reach the water surface and drive open-water evaporation. Cloud formation over the interior of Lake Okeechobee is suppressed because of a relatively large heat capacity for water that buffers convective fluxes of air that form clouds while rising and cooling.
Estimated evaporation rates obtained using five alternative methods were compared to measured Bowen-ratio energy-budget daily, monthly, and annual evaporation: the Penman, Priestly-Taylor, Mass-Transfer, Simple, and Turc equations. All five methods performed relatively well (within 10 percent of the Bowen ratio annual totals). The Penman, Priestley-Taylor, and Mass-Transfer methods captured relatively large evaporation rates that occurred in the winter due to cold fronts, because these methods account for large wind speeds and vapor pressure deficits associated with the regional cold fronts. For operational implementation, the Simple, Mass-Transfer, or Turc methods are likely preferable because of their simplicity, limited data requirements, and improved accuracy for computing monthly and annual evaporation totals. The Turc equation computed monthly evaporation within 8 percent of the Bowen-ratio method, while requiring only air temperature and solar radiation data. The Simple equation achieved similar accuracy while requiring only solar radiation data.
Released May 14, 2024 14:02 EST
2024, Scientific Investigations Report 2024-5019
Krishangi D. Groover, Miranda S. Fram, Zeno F. Levy
Groundwater quality in the western part of the Mojave Desert in San Bernardino County, California, was investigated in 2018 as part of the California State Water Resources Control Board Groundwater Ambient Monitoring and Assessment Program Priority Basin Project. The Mojave Basin Domestic-Supply Aquifer study unit (MOBS) region was divided into two study areas—floodplain and regional—to assess differences between the two major aquifers used for drinking water supply in the area. This assessment characterized the quality of ambient groundwater and not the quality of treated drinking water.
The study included three components: (1) a status assessment, which characterized the quality of groundwater resources used for domestic drinking-water supply in the floodplain and regional study areas; (2) a brief understanding assessment, which evaluated factors that could potentially affect the quality of groundwater used by domestic wells in the region; and (3) a comparative assessment between the groundwater resources used by domestic wells and public-supply wells in the two study areas. The domestic-well assessment was based on data collected by the U.S. Geological Survey from 48 domestic wells in January–May 2018. The public-supply assessment was based on data for samples from 322 public-supply wells in 2008–18, either collected by the U.S. Geological Survey or compiled from the California State Water Resources Control Boards Division of Drinking Water publicly available database.
Concentrations of water-quality constituents in ambient groundwater were compared to regulatory and non-regulatory benchmarks typically used by the State of California and Federal agencies as health-based or aesthetic standards for public drinking water. Relative concentrations, defined as the measured concentration divided by the benchmark concentration, were classified as high (greater than 1.0), moderate (greater than 0.5 for inorganic constituents or 0.1 for organic and special-interest constituents, and not high), or low (concentrations lower than moderate). The floodplain and regional study areas were divided into 15 and 35 grid cells, respectively, and grid-based methods were used to compute the areal proportions of the two study areas with high, moderate, or low relative concentrations of individual constituents and classes of constituents.
For the domestic-supply assessment, one or more inorganic constituents with health-based benchmarks were detected at high relative concentrations in 58 percent of the regional study area and 13 percent of the floodplain study area. The inorganic constituents with health-based benchmarks detected at high relative concentrations in the regional study area were arsenic, chromium and hexavalent chromium, fluoride, adjusted gross alpha particle activity, uranium, molybdenum, strontium, and nitrate; only arsenic was detected at high relative concentrations in the floodplain study area. One or more inorganic constituents with secondary maximum contaminant level benchmarks were detected at high concentrations in 15 and 6.7 percent of the regional and floodplain study areas, respectively. The constituents detected at high relative concentrations in the regional study area were total dissolved solids, chloride, sulfate, and iron; only total dissolved solids and sulfate were detected at high relative concentrations in the floodplain study area.
Organic constituents were not detected at moderate or high relative concentrations in either the regional or floodplain study areas. Volatile organic compounds were detected at low relative concentrations in 21 and 27 percent of the regional and floodplain study areas, respectively, and pesticides were detected at low relative concentrations in 9.1 and 20 percent of the regional and floodplain study areas, respectively. The only individual organic constituent detected in more than 10 percent of either study area was the trihalomethane trichloromethane. Total coliform bacteria were detected in 15 and 27 percent of the grid wells in the regional and floodplain study areas, respectively.
The greater prevalence of high relative concentrations of many inorganic constituents in the regional study area compared to the floodplain area likely indicates the greater diversity of geologic material at depth in aquifer material and generally finer-grained alluvium compared to the floodplain study area combined with generally older groundwater that has had more contact time with aquifer materials. In general, trace element concentrations (1) increased with increasing groundwater age, (2) increased with distance from recharge sources in the mountains, and (3) increased with closer proximity to some types of geological units. In general, groundwater from domestic wells in the floodplain study area is young, with most samples containing a component of modern groundwater based on tritium and unadjusted carbon-14 activities, whereas groundwater from domestic wells in the regional study area generally is old, with most samples having unadjusted carbon-14 ages of 5,000–40,000 years.
Public-supply wells in MOBS generally were deeper than domestic wells and presumably are in contact with older, more weathered alluvium that may have more mobile trace elements, such as arsenic or uranium. However, only 26 percent of the public-supply regional study area had high relative concentrations of inorganic constituents, compared to 58 percent for the domestic regional study area. The percentages of the public-supply and domestic floodplain study areas with high relative concentrations of inorganic constituents were 11 and 13 percent, respectively. The ages of groundwater used by public-supply and domestic wells in each study area were similar, which was not expected given the greater depth of the public-supply wells. Three potential factors may contribute to these results: (1) greater spatial footprint of domestic well network, which may result in domestic wells pumping groundwater from fractured bedrock or mineralized areas not used by public-supply wells; (2) greater pumping rates in public-supply wells, resulting in more water being withdrawn from coarse-grained, heterogeneous alluvium than finer-grained layers, which may have higher concentrations of (or more mobile) inorganic constituents; and (3) a greater degree of well management with public-supply wells, which may include pausing use of or decommissioning wells if treating or blending water is not feasible to lower constituent concentrations.
Released May 14, 2024 08:47 EST
2024, Ecosphere (15)
Casey A. Pennock, Brian Daniel Healy, Matthew R. Bogaard, Mark C. McKinstry, Keith B. Gido, C. Nathan Cathcart, Brian Hines
Fragmentation isolates individuals and restricts access to valuable habitat with severe consequences for populations, such as reduced gene flow, disruption of recolonization dynamics, reduced resiliency to disturbance, and changes in aquatic community structure. Translocations to mitigate the effects of fragmentation and habitat loss are common, but few are rigorously evaluated, particularly for fishes. Over six years, we translocated 1215 individuals of four species of imperiled fish isolated below a barrier on the San Juan River, Utah, USA, that restricts access to upstream habitat. We used re-encounter data (both passive integrated transponder tag and telemetry detections and physical recaptures) collected between 2016 and 2023, to inform a spatially explicit multistate mark–recapture model that estimated survival and transition probabilities of translocated and non-translocated individuals, both below and above the barrier. Individuals of all four species moved large (>200 km) distances upstream following translocation, with the maximum upstream encounter distance varying by species. Results from the multistate mark–recapture model suggested translocated fish survived at a higher rate compared with non-translocated fish below the barrier for three of the four species. Above the barrier, translocated individuals survived at similar rates as non-translocated fish for bluehead sucker (Catostomus discobolus) and flannelmouth sucker (Catostomus latipinnis), while survival rates of translocated endangered Colorado pikeminnow (Ptychocheilus lucius; mean, 95% CI: 0.75, 0.55–0.88) and endangered razorback sucker (Xyrauchen texanus; 0.86, 0.75–0.92) were higher relative to non-translocated individuals (Colorado pikeminnow: 0.52, 0.51–0.54; razorback sucker: 0.75, 0.74–0.75). Transition probabilities from above the barrier to below the barrier were generally low for three of the four species (all upper 95% CI ≤ 0.23), but they were substantially higher for razorback sucker. Our results suggest translocation to mitigate fragmentation and habitat loss can have demographic benefits for large-river fish species by allowing movements necessary to complete their life history in heterogeneous riverscapes. Further, given the costs or delays in providing engineered fish passage structures or in achieving dam removal, we suggest translocations may provide an alternative conservation strategy in fragmented river systems.
Released May 14, 2024 06:37 EST
2024, Environmental Evidence (13)
Avery Paxton, Iris Foxfoot, Christina Cutshaw, D'amy Steward, Leanne Poussard, Trevor Riley, Todd Swannack, Candice Piercy, Safra Altman, Brandon Puckett, Curt Storlazzi, Shay Viehman
Shallow, tropical coral reefs face compounding threats from climate change, habitat degradation due to coastal development and pollution, impacts from storms and sea-level rise, and pulse disturbances like blast fishing, mining, dredging, and ship groundings that reduce reef height and complexity. One approach toward restoring coral reef physical structure from such impacts is deploying built structures of artificial, natural, or hybrid (both artificial and natural) origin. Built structures range from designed modules and repurposed materials to underwater sculptures and intentionally placed natural rocks. Restoration practitioners and coastal managers increasingly consider incorporating – and in many cases have already begun to incorporate – built structures into coral reef-related applications, yet synthesized evidence on the ecological (coral-related; e.g., coral growth, coral survival) and physical performance of built structures in coral ecosystems across a variety of contexts (e.g., restoration, coastal protection, mitigation, tourism) is not readily available to guide decisions. To help fill this gap and inform management decisions, we systematically mapped the global distribution and abundance of published evidence on the ecological (coral-related) and physical performance of built structure interventions in shallow (≤ 30m), tropical (35°N to 35°S) coral ecosystems.
Released May 13, 2024 15:10 EST
2024, Open-File Report 2024-1023
Simon J. Cantrell, Jon B. Christopherson
The Joint Agency Commercial Imagery Evaluation (JACIE) partnership consists of six agencies representing the U.S. Government’s commitment to promoting the use of high-quality remotely sensed data to meet scientific and other Federal needs. These agencies are large consumers of remotely sensed data and bring extensive experience in the assessment and use of these data. The six agencies are as follows: National Aeronautics and Space Administration, National Geospatial-Intelligence Agency, National Oceanic and Atmospheric Administration, U.S. Department of Agriculture, U.S. Geological Survey, and National Reconnaissance Office.
JACIE was formed in 2001 to assess the quality of data from the nascent commercial high-resolution satellite industry. Since then, JACIE has expanded its purview to include data at various resolutions, including commercial and civil.
The processes and techniques used by the JACIE agencies to assess data quality have been compiled within this report to share them across the agencies and with others who want to assess remotely sensed imagery data or understand how data are assessed and reported by JACIE.
Released May 13, 2024 09:19 EST
2024, Scientific Investigations Report 2024-5036
Clinton R. Bailey, Carolyn M. Soderstrom, James J. Duncker
The Space to Grow program helps transform aging and neglected schoolyards of Chicago Public Schools into outdoor community spaces with the goal of promoting health and learning while addressing neighborhood flooding issues. Virgil I. Grissom Elementary School and Donald L. Morrill Math and Science School were selected in 2014 for schoolyard upgrades and the installation of various green infrastructure (GI) improvements. The U.S. Geological Survey installed sensors to measure precipitation, groundwater levels, and stormwater runoff volumes from September 1, 2016, to July 1, 2017.
At Virgil I. Grissom Elementary School, about 933,000 gallons of water fell on the schoolyard during the monitoring period. No discharge was recorded coming from the GI sewer lines, but backflow indicated water was flowing from the sewer line draining the impervious running track into the combined manhole structure and backwards into the GI retention basins (as designed). This design allowed for a 100-percent capture rate. Native soil at Virgil I. Grissom Elementary School also was conducive to rapid infiltration. Soil borings at Virgil I. Grissom Elementary School indicated about 10.5 feet (ft) of fine sand overlying silty clay to a depth of at least 16 ft. At Donald L. Morrill Math and Science School, about 1,120,000 gallons of water fell on the schoolyard during the monitoring period. About 72.5 precent of this water was discharged into the sewer system, and the other 27.5 percent was captured by the GI. Unlike Virgil I. Grissom Elementary School, the soil profile at Donald L. Morrill Math and Science School consisted of about 5 ft of clay loam overlying stiff blue clay to a depth of at least 12 ft. The sewer line coming from the GI under the football field was at the bottom of the reservoir. This design seemed to allow water to flow out of the line before being absorbed by the retention basin.
Released May 13, 2024 07:24 EST
2024, Canadian Journal of Zoology
Andrew Edgar Honsey, Katie Victoria Anweiler, David Bunnell, Cory Brant, Georgia Wende Hoffman, Brian O'Malley, Kevin Keeler, Chris Olds, Jeremy Kraus, Yu-Chun Kao, Wendylee Stott
Cisco (Coregonus artediLesueur, 1818) in the Laurentian Great Lakes declined throughout the 19th and 20th centuries. Managers are attempting to restore Great Lakes cisco and other coregonines using multiple approaches, including stocking. A potential obstacle to these efforts is that artificially reared coregonines can display deformities and morphological differences compared to wild fish, but the impacts of artificial rearing on cisco morphology are not well understood. We compared morphologies of wild cisco to their artificially reared offspring, including one family that was exposed to three rearing temperature treatments. We found that artificially reared cisco had smaller eyes, shallower bodies, fewer gill rakers, and longer paired fins than their wild parents. We also found that artificially reared cisco were pugheaded, and this result held for another cisco population and rearing facility. Across the temperature treatments we tested, rearing temperatures did not impact the degree of pugheadedness or other morphological differences. Our results have important implications for coregonine restoration efforts. Future work should evaluate whether morphological differences that arise through artificial rearing affect cisco fitness in the wild.
Released May 10, 2024 10:20 EST
2024, JGR Earth Surface
L. Stevens, S. Das, M. D. Behn, Jeffrey McGuire, Ching-Yao Lai, I. Joughin, S LaRochelle, M. Nettles
Supraglacial lakes have been observed to drain within hours of each other, leading to the hypothesis that stress transmission following one drainage may be sufficient to induce hydro-fracture-driven drainages of other nearby lakes. However, available observations characterizing drainage-induced stress perturbations have been insufficient to evaluate this hypothesis. Here, we use ice-sheet surface-displacement observations from a dense global positioning system array deployed in the Greenland Ice Sheet ablation zone to investigate elastic stress transmission between three neighboring supraglacial lake basins. We find that drainage of a central lake can place neighboring basins in either tensional or compressional stress relative to their hydro-fracture scarp orientations, either promoting or inhibiting hydro-fracture initiation beneath those lakes. For two lakes located within our array that drain close in time, we identify tensional surface stresses caused by ice-sheet uplift due to basal-cavity opening as the physical explanation for these lakes' temporally clustered hydro-fracture-driven drainages and frequent triggering behavior. However, lake-drainage-induced stresses in the up-flowline direction remain low beyond the margins of the drained lakes. This short stress-coupling length scale is consistent with idealized lake-drainage scenarios for a range of lake volumes and ice-sheet thicknesses. Thus, on elastic timescales, our observations and idealized-model results support a stress-transmission hypothesis for inducing hydro-fracture-driven drainage of lakes located within the region of basal cavity opening produced by the initial drainage, but refute this hypothesis for distal lakes.
Released May 10, 2024 07:04 EST
2024, Science of the Total Environment (932)
Michelle Lorah, Ke He, Lee Blaney, Denise M. Akob, Cassandra Rashan Harris, Andrea K. Tokranov, Zachary Ryan Hopkins, Brian Shedd
Perfluorooctane sulfonate (PFOS), one of the most frequently detectedper- and polyfluoroalkyl substances (PFAS) occurring in soil, surface water, and groundwater near sites contaminated with aqueous film-forming foam (AFFF), has proven to be recalcitrant to many destructive remedies, including chemical oxidation. We investigated the potential to utilize microbially mediated reduction (bioreduction) to degrade PFOS and other PFAS through addition of a known dehalogenating culture, WBC-2, to soil obtained from an AFFF-contaminated site. A substantial decrease in total mass of PFOS (soil and water) was observed in microcosms amended with WBC-2 and chlorinated volatile organic compound (cVOC) co-contaminants — 46.4±11.0% removal of PFOS over the 45-day experiment. In contrast, perfluorooctanoate (PFOA) and 6:2 fluorotelomer sulfonate (6:2 FTS) concentrations did not decrease in the same microcosms. The low or non-detectable concentrations of potential metabolites in full PFAS analyses, including after application of the total oxidizable precursor assay, indicated that defluorination occurred to non-fluorinated compounds or ultrashort-chain PFAS. Nevertheless, additional research on the metabolites and degradation pathways is needed. Population abundances of known dehalorespirers did not change with PFOS removal during the experiment, making their association with PFOS removal unclear. An increased abundance of sulfate reducers in the genusDesulfosporosinus(Firmicutes) andSulfurospirillum(Campilobacterota) was observed with PFOS removal, most likely linked to initiation of biodegradation by desulfonation. These results have important implications for development ofin situbioremediation methods for PFAS and advancing knowledge of natural attenuation processes.
Released May 10, 2024 06:20 EST
2024, Polar Biology (47) 551-568
Sarah M. Laske, Vanessa R. von Biela, Ashley E. Stanek, Kenneth H. Dunton
Rapid changes in sea ice extent and changes in freshwater inputs from land are rapidly changing the nature of Arctic estuarine ecosystems. In the Beaufort Sea, these nearshore habitats are known for their high productivity and mix of marine resident and diadromous fishes that have great subsistence value for Indigenous communities. There is, however, a lack of information on the spatial variation among Arctic nearshore fish communities as related to environmental drivers. In summers of 2017–2019, we sampled fishes in four estuarine ecosystems to assess community composition and relate fish abundance to temperature, salinity, and wind conditions. We found fish communities were heterogeneous over larger spatial extents with rivers forming fresh estuarine plumes that supported diadromous species (e.g., broad whitefishCoregonus nasus), while lagoons with reduced freshwater input and higher salinities were associated with marine species (e.g., saffron codEleginus gracilis). West–East directional winds accounted for up to 66% of the community variation, indicating importance of the wind-driven balance between fresh and marine water masses. Salinity and temperature accounted for up to 54% and 37% of the variation among lagoon communities, respectively. Recent sea ice declines provide more opportunity for wind to influence oceanographic conditions and biological communities. Current subsistence practices, future commercial fishing opportunities, and on-going oil and gas activities benefit from a better understanding of current fish community distributions. This work provides important data on fish spatial distributions and community composition, providing a basis for fish community response to changing climatic conditions and anthropogenic use.
Released May 09, 2024 06:55 EST
2024, River Research and Applications
Laura Rack, Mary Freeman, Ben N. Emanuel, Laura S. Craig, Stephen W. Golladay, Carol Yang, Seth J. Wenger
Managing aquatic ecosystems for people and nature can be improved by collaboration among scientists, managers, decision-makers, and other stakeholders. Many collaborative and interdisciplinary approaches have been developed to address the management of freshwater ecosystems; however, there are still barriers to overcome. We worked as part of a regional stakeholder group comprising municipal water utility operators, conservation organizations, academic partners, and other stakeholders to understand the effects of low-flow and drought on ecological functions of the upper Flint River, Georgia (USA), a free-flowing river important for municipal water supply, recreation, and native biota. We used published literature and locally targeted studies to identify quantitative flow targets that could be used to inform water management and drought planning. Drawing from principles of Translational Ecology, we relied on an iterative process to develop information needs for the group and maintained communication and engagement throughout data collection, analysis, and synthesis. We identified three quantitative flow benchmarks to evaluate the ecological impacts of drought in the river. The results were valuable to both the water utilities represented in the working group and State regional water planning, which is used to guide water management strategies and permitting for the basin. We identified principles that were important for the successful engagement in the working group and helped to overcome the challenge of working across sectors and without direct authority guiding the implementation of our work. Interdisciplinary work and creative solutions are crucial to plan for and adapt to greater pressure on our water resources.
Released May 09, 2024 06:46 EST
2024, International Journal of Digital Earth (17)
Adam Oliphant, Prasad Thenkabail, Pardhasaradhi Teluguntla, Itiya Aneece, Daniel Foley, Richard L. McCormick
Cropland fallowing is choosing not to plant a crop during a season when a crop is normally planted. It is an important component of many crop rotations and can improve soil moisture and health. Knowing which fields are fallow is critical to assess crop productivity and crop water productivity, needed for food security assessments. The annual spatial extent of cropland fallows is poorly understood within the United States (U.S.). The U.S. Department of Agriculture Cropland Data Layer does provide cropland fallow areas; however, at a significantly lower confidence than their cropland classes. This study developed a methodology to map cropland fallows within the Northern Great Plains region of the U.S. using an easily implementable decision tree algorithm leveraging training and validation data from wet (2019), normal (2015), and dry (2017) precipitation years to account for climatic variability. The decision trees automated cropland fallow algorithm (ACFA) was coded on a cloud platform utilizing remotely sensed, time-series data from the years 2010–2019 to separate cropland fallows from other land cover/land use classes. Overall accuracies varied between 96%-98%. Producer’s and user’s accuracies of cropland fallow class varied between 70-87%.
Released May 09, 2024 06:27 EST
2024, Science of the Total Environment (932)
Kathryn Delores Eckhoff, Sasha C. Reed, John B. Bradford, Nikita C. Daly, Keven Griffen, Robin H. Reibold, Randi Lupardus, Seth M. Munson, Aarin Sengsirirak, Miguel L. Villarreal, Michael C. Duniway
Drylands impacted by energy development often require costly reclamation activities to reconstruct damaged soils and vegetation, yet little is known about the effectiveness of reclamation practices in promoting recovery of soil quality due to a lack of long-term and cross-site studies. Here, we examined paired on-pad and adjacent undisturbed off-pad soil properties over a 22-year chronosequence of 91 reclaimed oil or gas well pads across soil and climate gradients of the Colorado Plateau in the southwestern United States. Our goals were to estimate the time required for soil properties to reach undisturbed conditions, examine the multivariate nature of soil quality following reclamation, and identify environmental factors that affect reclamation outcomes. Soil samples, collected in 2020 and 2021, were analyzed for biogeochemical pools (total nitrogen, and total organic and inorganic carbon), chemical characteristics (salinity, sodicity, pH), and texture. Predicted time to recovery across all sites was 29years for biogeochemical soil properties, 31years for soil chemical properties, and 6years for soil texture. Ordination of soil properties revealed differences between on- and off-pad soils, while site aridity explained variability in on-pad recovery. The predicted time to total soil recovery (distance between on- and off-pad in ordination space) was 96years, which was longer than any individual soil property. No site reached total recovery, indicating that individual soil properties alone may not fully indicate recovery in soil quality as soil recovery does not equal the sum of its parts. Site aridity was the largest predictor of reclamation outcomes, but the effects differed depending on soil type. Taken together, results suggest the recovery of soil quality - which reflects soil fertility, carbon sequestration potential, and other ecosystem functions - was influenced primarily by site setting, with soil type and aridity major mediators of on-pad carbon, salinity, and total soil recovery following reclamation.
Released May 08, 2024 08:43 EST
2024, Toxics (12)
Matthew V. Russell, Tiffany L. Messer, Deborah A. Repert, Richard L. Smith, Shannon Bartelt-Hunt, Daniel D. Snow, Ariel Reed
The use of wetlands as a treatment approach for nitrogen in runoff is a common practice in agroecosystems. However, nitrate is not the sole constituent present in agricultural runoff and other biologically active contaminants have the potential to affect nitrate removal efficiency. In this study, the impacts of the combined effects of four common veterinary antibiotics (chlortetracycline, sulfamethazine, lincomycin, monensin) on nitrate-N treatment efficiency in saturated sediments and wetlands were evaluated in a coupled microcosm/mesocosm scale experiment. Veterinary antibiotics were hypothesized to significantly impact nitrogen speciation (e.g., nitrate and ammonium) and nitrogen uptake and transformation processes (e.g., plant uptake and denitrification) within the wetland ecosystems. To test this hypothesis, the coupled study had three objectives: 1. assess veterinary antibiotic impact on nitrogen cycle processes in wetland sediments using microcosm incubations, 2. measure nitrate-N reduction in water of floating treatment wetland systems over time following the introduction of veterinary antibiotic residues, and 3. identify the fate of veterinary antibiotics in floating treatment wetlands using mesocosms. Microcosms containing added mixtures of the veterinary antibiotics had little to no effect at lower concentrations but stimulated denitrification potential rates at higher concentrations. Based on observed changes in the nitrogen loss in the microcosm experiments, floating treatment wetland mesocosms were enriched with 1000 μg L−1of the antibiotic mixture. Rates of nitrate-N loss observed in mesocosms with the veterinary antibiotic enrichment were consistent with the microcosm experiments in that denitrification was not inhibited, even at the high dosage. In the mesocosm experiments, average nitrate-N removal rates were not found to be impacted by the veterinary antibiotics. Further, veterinary antibiotics were primarily found in the roots of the floating treatment wetland biomass, accumulating approximately 190 mg m−2of the antibiotic mixture. These findings provide new insight into the impact that veterinary antibiotic mixtures may have on nutrient management strategies for large-scale agricultural operations and the potential for veterinary antibiotic removal in these wetlands.
Released May 08, 2024 06:50 EST
2024, Chemistry Select (9)
Steven Bustillos, Mario Christofides, Bonnie McDevitt, Madalyn S. Blondes, Ryan J. McAleer, Aaron M. Jubb, Bu Wang, Gaurav Sant, Dante Simonetti
An attractive technique for removing CO2from the environment is sequestration within stable carbonate solids (e. g., calcite). However, continuous addition of alkalinity is required to achieve favorable conditions for carbonate precipitation (pH>8) from aqueous streams containing dissolved CO2(pH<4.5) and Ca2+ions. In this study, a pH-swing process using ion exchange was demonstrated to process 300 L of produced water brine per day for CO2mineralization. Proton titration capacities were quantified for aqueous streams in equilibrium with gas streams at various concentrations of CO2(pCO2=0.03–0.20 atm) and at various flow rates (0.5–2.0 L min−1). Energy intensities for the process were determined to be between 30 and 65 kWh per tonne of CO2sequestered depending on the composition of the brine stream. A life cycle assessment was performed to analyze the net carbon emissions of the technology which indicated a net CO2reduction for pCO2≥0.12 atm (−0.06–−0.39 kg CO2e per kg precipitated CaCO3) utilizing calcium-rich brines. The results from this study indicate the ion exchange process can be used as a scalable method to provide alkalinity necessary for the capture and storage of CO2in Ca-rich waste streams.
Released May 07, 2024 10:25 EST
2024, Open-File Report 2024-1010
Kendra L. Russell, William J. Andrews, Vincent J. DiFrenna, J. Michael Norris, Robert R. Mason, Jr.
A Decree of the Supreme Court of the United States, entered June 7, 1954 (New Jersey v. New York, 347 U.S. 995), established the position of Delaware River Master within the U.S. Geological Survey. In addition, the Decree authorizes the diversion of water from the Delaware River Basin and requires compensating releases from specific reservoirs owned by New York City be made under the supervision and direction of the River Master. The Decree stipulates that the River Master provide reports to the Court, not less frequently than annually. This report is the 62nd annual report of the River Master of the Delaware River. This report covers the 2015 River Master report year, which is the period from December 1, 2014, to November 30, 2015.
During the report year, precipitation in the upper Delaware River Basin was 42.22 inches or 95 percent of the long-term average. The combined storage remained above 80 percent of the combined capacity until August 2015. The lowest combined storage of the report year was 57 percent of the total combined capacity on December 1, 2014. Delaware River Master operations during the year were conducted as stipulated by the Decree and the Flexible Flow Management Program.
Diversions from the Delaware River Basin by New York City and New Jersey fully complied with the Decree. The reservoir releases were made as directed by the River Master at rates designed to meet the flow objective for the Delaware River at Montague, New Jersey, on 72 days during the report year. Interim Excess Release Quantity and conservation releases, designed to relieve thermal stress and protect the fishery and aquatic habitat in the tailwaters of the reservoirs, were also made during the report year.
Water quality in the Delaware River estuary between the streamgages at Trenton, New Jersey, and Reedy Island Jetty, Delaware, was monitored at several locations. Data on water temperature, specific conductance, dissolved oxygen, and pH were collected continuously by electronic instruments at four sites.
Released May 07, 2024 07:12 EST
2024, Applied Geochemistry (168)
Peter B. McMahon, Matthew K. Landon, Michael J. Stephens, Kimberly A. Taylor, Michael Wright, Angela Hansen, Tamara E. C. Kraus, Isabelle M. Cozzarelli, David H. Shimabukuro, Theron A. Sowers, Justin T. Kulongoski, Andrew Hunt, Ruta Karolyte, Darren J. Hillegonds, Chris J. Ballentine
Like many hydrocarbon production areas in the U.S., the Poso Creek Oil Field in California includes and is adjacent to other land uses (agricultural and other developed lands) that affect the hydrology and geochemistry of the aquifer overlying and adjacent to oil development. We hypothesize that the distributions of hydrocarbons and arsenic in groundwater in such areas will be controlled by complex interactions between mixed land uses, oil-field infrastructure, and natural processes. In 2020–2021, samples of groundwater and surface water were collected and analyzed for a large suite of inorganic and organic chemicals and isotope and gas tracers to test this hypothesis. Those data are supplemented with ancillary data on historical geochemistry, hydrology, geology, and oil-field infrastructure. Hydrocarbons in groundwater (e.g., methane through pentane gases and benzene) are associated with natural processes (e.g., fault offsets or transition in sediment depositional environment) and oil-field infrastructure (e.g., fluid-migration pathways associated with uncemented annulus in oil wells or unlined pits). Arsenic concentrations >10μg per liter (μg/L; maximum concentration 12.9μg/L) are associated with natural processes in old, high-pH groundwater, and more recent recharge of water from natural and/or engineered recharge processes. Along the southwest margin of the oil field, pumping for drinking-water and irrigation supplies in combination with engineered groundwater recharge produce a depression in groundwater elevations where groundwater with elevated sulfate concentrations from agricultural areas and groundwater with hydrocarbons from the oil field mix to produce a zone of sulfate reduction that removes hydrocarbons and arsenic from groundwater but produces elevated sulfide (S2-) concentrations (maximum concentration 29mg per liter, mg/L). In this study, multiple approaches were required to resolve the overlapping effects of land uses, oil-field infrastructure, and natural processes on the distributions of hydrocarbons and arsenic in groundwater. The combined use of geographic, historical, physical, chemical, isotopic, and other information to constrain processes could be a useful approach for studies in other hydrocarbon-production areas. This is particularly important where land uses affect aquifer hydrology to an extent that causes mixing of groundwaters with different chemical compositions.
Released May 06, 2024 13:30 EST
2024, Scientific Investigations Report 2023-5145
Joel William Homan
The Grand Valley in western Colorado is in the semiarid Southwest United States. The north side of the Grand Valley has many ungaged ephemeral streams, which are of particular interest because (1) the underlying bedrock geology, Late Cretaceous Mancos Shale, is a sedimentary rock deposit identified as a major salinity contributor to the Colorado River and (2) despite infrequent streamflows of short duration, monsoon-derived floods in these ephemeral streams can carry substantial amounts of sediment downstream, affecting upstream and downstream banks and channel cross sections. The study area is of interest, because salinity, or the total dissolved solids concentration, in the Colorado River causes an estimated $300 million to $400 million per year in economic damages in the United States, and it is estimated 62 percent of the Upper Colorado River Basin’s total dissolved solid loads originate from geologic sources. In an effort to minimize salt contributions to the Colorado River from public lands administered by the Bureau of Land Management, a comprehensive salinity control approach is typically used to reduce nonpoint sources of salinity through land management techniques and practices.
In 2018, the U.S. Geological Survey, in cooperation with the Bureau of Land Management, began an assessment of ephemeral streams located on the north side of the Grand Valley, western Colorado, to characterize stream channel stability and identify mechanisms affecting erosion. The U.S. Geological Survey developed a method for automatically extracting channel cross-section geometry from existing remotely sensed terrain models. Based on estimated flood stage and surrogate streamflows, hydraulic characteristics were calculated. Furthermore, the channel geometries and hydraulic characteristics were used to estimate channel stability using a statistical model.
Cross-section stabilities were determined from a stream channel stability assessment for a subset of 1,406 visited (field observed) locations out of 13,415 cross sections, which were delineated from remotely sensed terrain models. The application of Manning’s resistance equation in combination with multiple logistic regression models demonstrated channel stability can be estimated with a 0.845 goodness of fit for a validation dataset when using a combination of drainage area, width-to-depth ratio, sinuosity, and shear stress as the explanatory variables. Stream channel stability was extrapolated for 13,415 unvisited (not field observed) cross sections using the multiple logistic regression model and defined explanatory variables. Mapping of the ephemeral streams and their associated stabilities may be used by the Bureau of Land Management to prioritize areas for remediation or changes in management strategies to reduce sediment and salinity loading to the Colorado River.
The study found channel stability within the ephemeral streams to be spatially variable, longitudinally discontinuous, and dictated by changes in channel bed slope. The stable ephemeral streams were relatively wide and shallow and often had smaller drainage areas with less potential for producing shear stresses capable of overcoming channel adhesion. A change in channel bed slope can provide the means necessary to generate shear stresses appropriate to initiate erosion and a subsequent stability transition to incising channels. Channel widening happens when either or both banks of an incising channel reach a critical height for mass wasting, or when channel curvature causes higher sidewall stress. Regardless, widening channels can promote increases in sinuosity and subsequently reduce steep channel bed slopes. Consequently, stable and widening channels can have comparable bed slopes, making channel bed slope a poor explanatory variable to predict channel stability overall, despite its function to initiate channel instability.
The results were based on a surrogate 0.10 annual exceedance probability (AEP; return period equal to the 10-year flood) interval streamflow, although it was recognized fluctuations in streamflow would also affect channel stability. Past and current changes within the study area affect streamflow; therefore, mechanisms affecting erosion include land use disturbances, soil compaction, loss of vegetation cover, drought, less frequent and more extreme precipitation, and fires—which all intensify the potential runoff and erosion within the study area.
Released May 06, 2024 07:07 EST
2024, PNAS (121)
Yun Tao, Alan Hastings, Kevin D. Lafferty, Ilkka Hanski, Otso Ovaskainen
Habitat loss and isolation caused by landscape fragmentation represent a growing threat to global biodiversity. Existing theory suggests that the process will lead to a decline in metapopulation viability. However, since most metapopulation models are restricted to simple networks of discrete habitat patches, the effects of real landscape fragmentation, particularly in stochastic environments, are not well understood. To close this major gap in ecological theory, we developed a spatially explicit, individual-based model applicable to realistic landscape structures, bridging metapopulation ecology and landscape ecology. This model reproduced classical metapopulation dynamics under conventional model assumptions, but on fragmented landscapes, it uncovered general dynamics that are in stark contradiction to the prevailing views in the ecological and conservation literature. Notably, fragmentation can give rise to a series of dualities: a) positive and negative responses to environmental noise, b) relative slowdown and acceleration in density decline, and c) synchronization and desynchronization of local population dynamics. Furthermore, counter to common intuition, species that interact locally (“residents”) were often more resilient to fragmentation than long-ranging “migrants.” This set of findings signals a need to fundamentally reconsider our approach to ecosystem management in a noisy and fragmented world.
Released May 06, 2024 06:59 EST
2024, Natural Hazards and Earth System Sciences (24) 1579-1605
Rex L. Baum, Dianne L. Brien, Mark E. Reid, William Schulz, Matthew J. Tello
Hurricane Maria induced about 70 000 landslides throughout Puerto Rico, USA, including thousands each in three municipalities situated in Puerto Rico's rugged Cordillera Central range. By combining a nonlinear soil-depth model, presumed wettest-case pore pressures, and quasi-three-dimensional (3D) slope-stability analysis, we developed a landslide susceptibility map that has very good performance and continuous susceptibility zones having smooth, buffered boundaries. Our landslide susceptibility map enables assessment of potential ground-failure locations and their use as landslide sources in a companion assessment of inundation and debris-flow runout. The quasi-3D factor of safety,F3, showed strong inverse correlation to landslide density (high density at lowF3). Area under the curve (AUC) of true positive rate (TPR) versus false positive rate (FPR) indicated success ofF3in identifying head-scarp points (AUC = 0.84) and source-area polygons (0.85 ≤ AUC ≤ 0.88). The susceptibility zones enclose specific percentages of observed landslides. Thus, zone boundaries use successiveF3levels for increasing TPR of landslide head-scarp points, with zones bounded byF3at TPR = 0.75, very high;F3at TPR = 0.90, high; and the remainder moderate to low. The very high susceptibility zone, with 118 landslides km−2, covered 23 % of the three municipalities. The high zone (51 landslides km−2) covered another 10 %.
Released May 06, 2024 06:53 EST
2024, Water Resource Research (60)
Samuel Zipper, Andrea E. Brookfield, Hoori Ajami, Jessica R. Ayers, Chris Beightel, Michael N. Fienen, Tom Gleeson, John C. Hammond, Mary C Hill, Anthony D Kendall, Benjamin Kerr, Dana A. Lapides, Misty Porter, S. Parimalarenganayaki, Melissa Rohde, Chloe Wardropper
Reductions in streamflow caused by groundwater pumping, known as “streamflow depletion,” link the hydrologic process of stream-aquifer interactions to human modifications of the water cycle. Isolating the impacts of groundwater pumping on streamflow is challenging because other climate and human activities concurrently impact streamflow, making it difficult to separate individual drivers of hydrologic change. In addition, there can be lags between when pumping occurs and when streamflow is affected. However, accurate quantification of streamflow depletion is critical to integrated groundwater and surface water management decision making. Here, we highlight research priorities to help advance fundamental hydrologic science and better serve the decision-making process. Key priorities include (a) linking streamflow depletion to decision-relevant outcomes such as ecosystem function and water users to align with partner needs; (b) enhancing partner trust and applicability of streamflow depletion methods through benchmarking and coupled model development; and (c) improving links between streamflow depletion quantification and decision-making processes. Catalyzing research efforts around the common goal of enhancing our streamflow depletion decision-support capabilities will require disciplinary advances within the water science community and a commitment to transdisciplinary collaboration with diverse water-connected disciplines, professions, governments, organizations, and communities.
Released May 06, 2024 06:05 EST
2024, Earth and Planetary Science Letters (637)
Yoshiki Yamazaki, Thorne Lay, Kwok Fai Cheung, Robert C. Witter, SeanPaul La Selle, Bruce E. Jaffe
The great 1957 Aleutian Islands earthquake ruptured ∼1200 km of the plate boundary along the Aleutian subduction zone and produced a destructive tsunami across Hawaiʻi. Early seismic and tsunami analyses indicated that large megathrust fault slip was concentrated in the western Aleutian Islands, but tsunami waves generated by slip in the west cannot explain the large observed runup in Hawaiʻi far to the southeast. Recently mapped 1957 geologic deposits on eastern Aleutian Islands suggest occurrence of very large nearby slip. Jointly modeling tsunami runup along the eastern Aleutian and Hawaiian Islands together with tide gauge recordings across the Pacific resolves 12-26 m shallow slip along 600 km of the eastern Aleutian Islands in addition to modest, deeper western slip inferred from seismic records. The eastern near-trench slip results in anMW8.3-8.6 tsunami earthquake component of theMW8.6-8.8 rupture, comparable in size to the adjacent 1946 Aleutian tsunami earthquake to the east. The reexamination of the 1957 rupture confirms the tsunami hazards posed by the eastern Aleutian subduction zone to Hawaiʻi and lays the groundwork for investigation of large prehistoric earthquakes through modeling tsunami runup inferred from stratigraphic observations to constrain their rupture processes.
