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At least 1,135 records · Page 63Linked to original sources

USGS2012

Estimation of evaporation from open water - A review of selected studies, summary of U.S. Army Corps of Engineers data collection and methods, and evaluation of two methods for estimation of evaporation from five reservoirs in Texas

Organizations responsible for the management of water resources, such as the U.S. Army Corps of Engineers (USACE), are tasked with estimation of evaporation for water-budgeting and planning purposes. The USACE has historically used Class A pan evaporation data (pan data) to estimate evaporation from reservoirs but many USACE Districts have been experimenting with other techniques for an alternative to collecting pan data. The energy-budget method generally is considered the preferred method for accurate estimation of open-water evaporation from lakes and reservoirs. Complex equations to estimate evaporation, such as the Penman, DeBruin-Keijman, and Priestley-Taylor, perform well when compared with energy-budget method estimates when all of the important energy terms are included in the equations and ideal data are collected. However, sometimes nonideal data are collected and energy terms, such as the change in the amount of stored energy and advected energy, are not included in the equations. When this is done, the corresponding errors in evaporation estimates are not quantifiable. Much simpler methods, such as the Hamon method and a method developed by the U.S. Weather Bureau (USWB) (renamed the National Weather Service in 1970), have been shown to provide reasonable estimates of evaporation when compared to energy-budget method estimates. Data requirements for the Hamon and USWB methods are minimal and sometimes perform well with remotely collected data. The Hamon method requires average daily air temperature, and the USWB method requires daily averages of air temperature, relative humidity, wind speed, and solar radiation. Estimates of annual lake evaporation from pan data are frequently within 20 percent of energy-budget method estimates. Results of evaporation estimates from the Hamon method and the USWB method were compared against historical pan data at five selected reservoirs in Texas (Benbrook Lake, Canyon Lake, Granger Lake, Hords Creek Lake, and Sam Rayburn Lake) to evaluate their performance and to develop coefficients to minimize bias for the purpose of estimating reservoir evaporation with accuracies similar to estimates of evaporation obtained from pan data. The modified Hamon method estimates of reservoir evaporation were similar to estimates of reservoir evaporation from pan data for daily, monthly, and annual time periods. The modified Hamon method estimates of annual reservoir evaporation were always within 20 percent of annual reservoir evaporation from pan data. Unmodified and modified USWB method estimates of annual reservoir evaporation were within 20 percent of annual reservoir evaporation from pan data for about 91 percent of the years compared. Average daily differences between modified USWB method estimates and estimates from pan data as a percentage of the average amount of daily evaporation from pan data were within 20 percent for 98 percent of the months. Without any modification to the USWB method, average daily differences as a percentage of the average amount of daily evaporation from pan data were within 20 percent for 73 percent of the months. Use of the unmodified USWB method is appealing because it means estimates of average daily reservoir evaporation can be made from air temperature, relative humidity, wind speed, and solar radiation data collected from remote weather stations without the need to develop site-specific coefficients from historical pan data. Site-specific coefficients would need to be developed for the modified version of the Hamon method.

Texas↗

USGS2015

Mining for metals in society's waste

Metals are crucial to society and enable our modern standard of living. Look around and you can't help but see products made of metals. For instance, a typical gasoline-powered automobile contains over a ton of iron and steel, 240 pounds of aluminum, 42 pounds of copper, 41 pounds of silicon, 22 pounds of zinc and more than 30 other mineral commodities including titanium, platinum and gold. Metals and minerals are natural resources that human beings have been mining for thousands of years. Contemporary metal mining is dominated by iron ore, copper and gold, with 2 billion tons of iron ore, nearly 20 million tons of copper and 2,000 tons of gold produced every year. Tens to hundreds of tons of other metals that are essential components for electronics, green energy production, and high-technology products are produced annually.

The Conversation↗

USGS2008

Global daily reference evapotranspiration modeling and evaluation

Accurate and reliable evapotranspiration (ET) datasets are crucial in regional water and energy balance studies. Due to the complex instrumentation requirements, actual ET values are generally estimated from reference ET values by adjustment factors using coefficients for water stress and vegetation conditions, commonly referred to as crop coefficients. Until recently, the modeling of reference ET has been solely based on important weather variables collected from weather stations that are generally located in selected agro-climatic locations. Since 2001, the National Oceanic and Atmospheric Administration’s Global Data Assimilation System (GDAS) has been producing six-hourly climate parameter datasets that are used to calculate daily reference ET for the whole globe at 1-degree spatial resolution. The U.S. Geological Survey Center for Earth Resources Observation and Science has been producing daily reference ET (ETo) since 2001, and it has been used on a variety of operational hydrological models for drought and streamflow monitoring all over the world. With the increasing availability of local station-based reference ET estimates, we evaluated the GDAS-based reference ET estimates using data from the California Irrigation Management Information System (CIMIS). Daily CIMIS reference ET estimates from 85 stations were compared with GDAS-based reference ET at different spatial and temporal scales using five-year daily data from 2002 through 2006. Despite the large difference in spatial scale (point vs . ∼100 km grid cell) between the two datasets, the correlations between station-based ET and GDAS-ET were very high, exceeding 0.97 on a daily basis to more than 0.99 on time scales of more than 10 days. Both the temporal and spatial correspondences in trend/pattern and magnitudes between the two datasets were satisfactory, suggesting the reliability of using GDAS parameter-based reference ET for regional water and energy balance studies in many parts of the world. While the study revealed the potential of GDAS ETo for large-scale hydrological applications, site-specific use of GDAS ETo in complex hydro-climatic regions such as coastal areas and rugged terrain may require the application of bias correction and/or disaggregation of the GDAS ETo using downscaling techniques.

Journal of the American Water Resources Associatio↗

USGS2023

A novel non-destructive workflow for examining germanium and co-substituents in ZnS

A suite of complementary techniques was used to examine germanium (Ge), a byproduct critical element, and co-substituent trace elements in ZnS and mine wastes from four mineral districts where germanium is, or has been, produced within the United States. This contribution establishes a comprehensive workflow for characterizing Ge and other trace elements, which captures the full heterogeneity of samples through extensive pre-characterization. This process proceeded from optical microscopy, to scanning electron microscopy and cathodoluminescence (CL) imaging, to electron microprobe analysis, prior to synchrotron-based investigations. Utilizing non-destructive techniques enabled reanalysis, which proved essential for verifying observations and validating unexpected results. In cases where the Fe content was <0.3 wt% in ZnS, cathodoluminescence imaging proved to be an efficient means to qualitatively identify trace element zonation that could then be further explored by other micro-focused techniques. Micro-focused X-ray diffraction was used to map the distribution of the non-cubic ZnS polymorph, whereas micro-focused X-ray fluorescence (μ-XRF) phase mapping distinguished between Ge 4+ hosted in primary ZnS and a weathering product, hemimorphite [Zn 4 Si 2 O 7 (OH) 2 ·H 2 O]. Microprobe data and μ-XRF maps identified spatial relationships among trace elements in ZnS and implied substitutional mechanisms, which were further explored using Ge and copper (Cu) X-ray absorption near-edge spectroscopy (XANES). Both oxidation states of Ge (4+ and 2+) were identified in ZnS along with, almost exclusively, monovalent Cu. However, the relative abundance of Ge oxidation states varied among mineral districts and, sometimes, within samples. Further, bulk XANES measurements typically agreed with micro-focused XANES (μ-XANES) spectra, but unique micro-environments were detected, highlighting the importance of complementary bulk and micro-focused measurements. Some Ge μ-XANES utilized a high energy resolution fluorescence detector, which improved spectral resolution and spectral signal-to-noise ratio. This detector opens new opportunities for exploring byproduct critical elements in complex matrices. Overall, the non-destructive workflow employed here can be extended to other byproduct critical elements to more fully understand fundamental ore enrichment processes, which have practical implications for critical element exploration, resource quantification, and extraction.

Frontiers in Earth Science↗

USGS2001

Effects of exotic species on Yellowstone's grizzly bears

Humans have affected grizzly bears ( Ursus arctos horribilis ) by direct mortality, competition for space and resources, and introduction of exotic species. Exotic organisms that have affected grizzly bears in the Greater Yellowstone Area include common dandelion ( Taraxacum officinale ), nonnative clovers ( Trifolium spp.), domesticated livestock, bovine brucellosis ( Brucella abortus ), lake trout ( Salvelinus namaycush ), and white pine blister rust ( Cronartium ribicola ). Some bears consume substantial amounts of dandelion and clover. However, these exotic foods provide little digested energy compared to higher-quality bear foods. Domestic livestock are of greater energetic value, but use of this food by bears often leads to conflicts with humans and subsequent increases in bear mortality. Lake trout, blister rust, and brucellosis diminish grizzly bears foods. Lake trout prey on native cutthroat trout ( Oncorhynchus clarkii ) in Yellowstone Lake; white pine blister rust has the potential to destroy native whitebark pine ( Pinus albicaulis ) stands; and management response to bovine brucellosis, a disease found in the Yellowstone bison (Bison bison) and elk ( Cervus elaphus ), could reduce populations of these 2 species. Exotic species will likely cause more harm than good for Yellowstone grizzly bears. Managers have few options to mitigate or contain the impacts of exotics on Yellowstone's grizzly bears. Moreover, their potential negative impacts have only begun to unfold. Exotic species may lead to the loss of substantial highquality grizzly bear foods, including much of the bison, trout, and pine seeds that Yellowstone grizzly bears currently depend upon.

Wyoming↗

USGS2016

The chemistry and isotopic composition of waters in the low-enthalpy geothermal system of Cimino-Vico Volcanic District, Italy

Geothermal energy exploration is based in part on interpretation of the chemistry, temperature, and discharge rate of thermal springs. Here we present the major element chemistry and the δD, δ 18 O, 87 Sr/ 86 Sr and δ 11 B isotopic ratio of groundwater from the low-enthalpy geothermal system near the city of Viterbo in the Cimino-Vico volcanic district of west-Central Italy. The geothermal system hosts many thermal springs and gas vents, but the resource is still unexploited. Water chemistry is controlled by mixing between low salinity,HCO 3 -rich fresh waters (<24.2°C) flowing in shallow volcanic rocks and SO 4 -rich thermal waters (25.3°C to 62.2°C) ascending from deep, high permeability Mesozoic limestones. The (equivalent) SO 4 /Cl (0.01–0.02), Na/Cl (2.82–5.83) and B/Cl ratios (0.02–0.38) of thermal waters differs from the ratios in other geothermal systems from Central Italy, probably implying a lack of hydraulic continuity across the region. The δ 18 O (−6.6‰ to −5.9‰) and δD (−40.60‰ to −36.30‰) isotopic composition of spring water suggest that the recharge area for the geothermal system is the summit region of Mount Cimino. The strontium isotope ratios ( 87 Sr/ 86 Sr) of thermal waters (0.70797–0.70805) are consistent with dissolution of the Mesozoic evaporite-carbonate units that constitute the reservoir, and the ratios of cold fresh waters mainly reflect shallow circulation through the volcanic cover and some minor admixture (<10%) of thermal water as well. The boron isotopic composition (δ 11 B) of fresh waters (−5.00 and 6.12‰) is similar to that of the volcanic cover, but the δ 11 B of thermal waters (−8.37‰ to −4.12‰) is a mismatch for the Mesozoic reservoir rocks and instead reflects dissolution of secondary boron minerals during fluid ascent through flysch units that overlie the reservoir. A slow and tortuous ascent enhances extraction of boron but also promotes conductive cooling, partially masking the heat present in the reservoir. Overall data from this study is consistent with previous studies that concluded that the geothermal system has a large energy potential.

Journal of Volcanology and Geothermal Research↗

USGS1985

Remote sensing; a geophysical perspective

In this review of developments in the field of remote sensing from a geophysical perspective, the subject is limited to the electromagnetic spectrum from 0.4 mu m to 25 cm. Three broad energy categories are covered: solar reflected, thermal infrared, and microwave.The reflected solar region has been the most intensely studied. Photointerpretation of images from individual spectral bands or from color composites remains the most widely used method of analysis. New instrumentation and digital processing, based on analysis of laboratory and field spectra, provide significant advances that are beginning to be applied to resource exploration. Color compositing techniques have been effectively used to detect the characteristic spectral reflectance features of iron oxides and hydroxyl-bearing materials in satellite multispectral data for mapping areas of hydrothermal alteration. Airborne spectrometers can now detect individual spectral features of many minerals which are diagnostic of different stages of hydrothermal alteration. Evolution was from discrimination, based on empirical experience, to mineralogic identification and leading to quantification. Current developments also indicate new, promising extensions to vegetated terrains.Advances in thermal infrared studies are due to development of thermal models that permit mapping of physical property variations and to detection of spectral differences that provide important compositional information. Analysis techniques are still in their infancy, and thermal satellite data remain appropriate only for regional investigations.Microwave data have been acquired mainly with radar systems, which can provide very high resolution from space, but use of textural and slope information has had limited application. Long-wavelength radiation has been shown to penetrate dry materials, and this may be applicable in extremely arid regions.

Geophysics↗

USGS2019

Three-dimensional geologic mapping to assess geothermal potential: Examples from Nevada and Oregon

Geologic structure plays an important role in controlling fluid flow in geothermal systems. In particular, very complex structural settings, consisting of many closely spaced and intersecting faults, host many geothermal systems. To elucidate the key geologic factors that affect fault-controlled geothermal circulation, it is critical to precisely characterize the structural and stratigraphic geometries in these complex settings. Here, we present a methodology and the results of 3D geologic analyses of two geothermal systems in the Basin and Range, USA. This methodology is a quantitative and geologically focused technique that can be used to precisely characterize geothermal areas, in a time when future geothermal growth demands increased exploration precision and efficiency. Surficial and subsurface geologic and geophysical data are synthesized in the construction of detailed 3D geologic maps of geothermal areas. Based on these 3D geologic maps, we examine several geologic attributes that control permeability development and geothermal fluid flow along faults. We use the stress state of faults and the distribution of structural discontinuities (i.e., fault intersections and fault terminations) to identify locations of upflow along faults in these geothermal systems. These results and the methodology presented herein are directly applicable to structurally controlled geothermal fields in the Basin and Range and worldwide. As development focus shifts toward blind geothermal resources, integration of precisely characterized subsurface structural information into exploration methods will be increasingly critical to continued growth in geothermal exploration and development.

Nevada, Oregon↗

USGS2009

Ecological assessment of streams in the Powder River Structural Basin, Wyoming and Montana, 2005-06

Energy and mineral development, particularly coalbed natural gas development, is proceeding at a rapid pace in the Powder River Structural Basin (PRB) in northeastern Wyoming. Concerns about the potential effects of development led to formation of an interagency working group of primarily Federal and State agencies to address these issues in the PRB in Wyoming and in Montana where similar types of resources exist but are largely undeveloped. Under the direction of the interagency working group, an ecological assessment of streams in the PRB was initiated to determine the current status (2005–06) and to establish a baseline for future monitoring. The ecological assessment components include assessment of stream habitat and riparian zones as well as assessments of macroinvertebrate, algal, and fish communities. All of the components were sampled at 47 sites in the PRB during 2005. A reduced set of components, consisting primarily of macroinvertebrate and fish community assessments, was sampled in 2006. Related ecological data, such as habitat and fish community data collected from selected sites in 2004, also are included in this report. The stream habitat assessment included measurement of channel features, substrate size and embeddedness, riparian vegetation, and reachwide characteristics. The width-to-depth ratio (bankfull width/bankfull depth) tended to be higher at sites on the main-stem Powder River than at sites on the main-stem Tongue River and at sites on tributary streams. The streambed substrate particle size was largest at sites on the main-stem Tongue River and smallest at sites on small tributary streams such as Squirrel Creek and Otter Creek. Total vegetative cover at the ground level, understory, and canopy layers ranged from less than 40 percent at a few sites to more than 90 percent at many of the sites. A bank-stability index indicated that sites in the Tongue River drainage were less at risk of bank failure than sites on the main-stem Powder River. Macroinvertebrate communities showed similarity at the river-drainage scale. Macroinvertebrate communities at sites with mountainous headwaters and snowmelt-driven hydrology, such as Clear Creek, Crazy Woman Creek, and Goose Creek, showed similarity with communities from the main-stem Tongue River. The data also indicated similarity among sites on the main-stem Powder River and among small tributaries of the Tongue River. Data analyses using macroinvertebrate observed/expected models and multimetric indices developed by the States of Wyoming and Montana indicated a tendency toward declining biological condition in the downstream direction along the Tongue River. Biological condition for the main-stem Powder River generally improved downstream, from below Salt Creek to near the Wyoming/Montana border, followed by a general decline downstream from the border to the confluence with the Yellowstone River. The biological condition generally was not significantly different between 2005 and 2006, although streamflow was less in 2006 because of drought. Algal communities showed similarity at the river-drainage scale with slight differences from the pattern observed in the macroinvertebrate communities. Although the algal communities from Clear Creek and Goose Creek were similar to those from the main-stem Tongue River, as was true of the macroinvertebrate communities, the algal communities from Crazy Woman Creek had more similarity to those of main-stem Powder River sites than to the Tongue River sites, contrary to the macroinvertebrates. Ordination of algal communities, as well as diatom metrics including salinity and dominant taxa, indicated substantial variation at two sites along the main stem of the Powder River. Fish communities of the PRB were most diverse in the Tongue River drainage. In part due to the effects of Tongue River Reservoir, 15 species of fish were found in the Tongue River drainage that were not found in the Cheyenne, Belle Fourche, or Little Powder River drainages. The number of introduced species and relative abundance of introduced species of fish were higher in the Tongue River and other drainages than at sites on the main-stem Powder River. Although non-native species were identified in the Powder River, the native fish community is largely intact. Western silvery minnow and sturgeon chub—species of special concern—were identified only at sites on the main-stem Powder River and were most common in the Montana segment of the main stem. Fish and habitat sampling on the main-stem Powder River indicated affinity of some species for certain habitats such as pools, runs, riffles, backwaters, or shoals.

Montana, Wyoming↗

USGS2016

An international borderland of concern: Conservation of biodiversity in the Lower Rio Grande Valley

The Lower Rio Grande Valley (LRGV) of southern Texas is located on the United States-Mexico borderland and represents a 240-kilometer (150-mile) linear stretch that ends at the Gulf of Mexico. The LRGV represents a unique transition between temperate and tropical conditions and, as such, sustains an exceptionally high diversity of plants and animals—some of them found in few, or no other, places in the United States. Examples include Leopardus pardalis albescens (northern ocelot) and Falco femoralis septentrionalis (northern aplomado falcon)—both endangered in the United States and emblematic of the LRGV. The U.S. Fish and Wildlife Service (USFWS) manages three national wildlife refuges (Santa Ana, Lower Rio Grande Valley, and Laguna Atascosa) that together make up the South Texas Refuge Complex, which actively conserves biodiversity in about 76,006 hectares (187,815.5 acres) of native riparian and upland habitats in the LRGV. These diminished habitats harbor many rare, threatened, and endangered species. This report updates the widely used 1988 USFWS biological report titled “Tamaulipan Brushland of the Lower Rio Grande Valley of South Texas: Description, Human Impacts, and Management Options” by synthesizing nearly 400 peer-reviewed scientific publications that have resulted from biological and sociological research conducted specifically in the four Texas counties of the LRGV in the past nearly 30 years. This report has three goals: (1) synthesize scientific insights gained since 1988 related to the biology and management of the LRGV and its unique biota, focusing on flora and fauna of greatest conservation concern; (2) update ongoing challenges facing Federal and State agencies and organizations that focus on conservation or key natural resources in the LRGV; and (3) redefine conservation opportunities and land-acquisition strategies that are feasible and appropriate today, given the many new and expanding constraints that challenge conservation activities in the LRGV. The LRGV faces every contemporary conservation challenge of the 21st century, but ongoing human population growth and its associated demands, international border issues, and oil, gas, and alternative energy development dominate impacts that affect conservation in the LRGV. Continued careful syntheses of existing and future information collected in the LRGV are needed on many biological and sociological topics to guide conservation activities. Quick response will no doubt be necessary to face contemporary and difficult-to-predict challenges such as climate change, diminished water availability and quality, spread of invasive species, and habitat loss and fragmentation. Complexities of a guarded international borderland add pressure to small patches of native habitat that remain in many places of the LRGV, particularly along the Rio Grande. Large connected corridors of restored native habitat could be the best option to maintain, and even enhance, the exceptional biodiversity of the LRGV in the face of exceptional human demand.

Texas↗

USGS1968

Measurement of peak discharge at culverts by indirect methods

This chapter classifies culvert flow into six types, gives discharge equations based on continuity and energy equations, and describes procedures for measuring peak discharges using culverts in the field. Discharge coefficients for a variety of geometries and flow types arc given. Ten examples detail step-by-step computation procedures.

Techniques of Water-Resources Investigations↗

USGS2014

Development of the Coastal Storm Modeling System (CoSMoS) for predicting the impact of storms on high-energy, active-margin coasts

The Coastal Storm Modeling System (CoSMoS) applies a predominantly deterministic framework to make detailed predictions (meter scale) of storm-induced coastal flooding, erosion, and cliff failures over large geographic scales (100s of kilometers). CoSMoS was developed for hindcast studies, operational applications (i.e., nowcasts and multiday forecasts), and future climate scenarios (i.e., sea-level rise + storms) to provide emergency responders and coastal planners with critical storm hazards information that may be used to increase public safety, mitigate physical damages, and more effectively manage and allocate resources within complex coastal settings. The prototype system, developed for the California coast, uses the global WAVEWATCH III wave model, the TOPEX/Poseidon satellite altimetry-based global tide model, and atmospheric-forcing data from either the US National Weather Service (operational mode) or Global Climate Models (future climate mode), to determine regional wave and water-level boundary conditions. These physical processes are dynamically downscaled using a series of nested Delft3D-WAVE (SWAN) and Delft3D-FLOW (FLOW) models and linked at the coast to tightly spaced XBeach (eXtreme Beach) cross-shore profile models and a Bayesian probabilistic cliff failure model. Hindcast testing demonstrates that, despite uncertainties in preexisting beach morphology over the ~500 km alongshore extent of the pilot study area, CoSMoS effectively identifies discrete sections of the coast (100s of meters) that are vulnerable to coastal hazards under a range of current and future oceanographic forcing conditions, and is therefore an effective tool for operational and future climate scenario planning.

Natural Hazards↗

USGS2018

Novel landscape elements within natural gas fields increase densities but not fitness of an important songbird nest predator

Identifying the elements within human-altered landscapes most associated with population and community changes is critical for conservation and management of sensitive species. We investigated which features of habitat change from natural gas development best explained the density of deer mice ( Peromyscus maniculatus ), an important nest predator of declining sagebrush-obligate songbirds. During 2014–2016, we quantified the spatial extent of habitat change (well pads, roads, and reclaimed areas [i.e., reseeded soils]) surrounding 12 sites spanning two natural gas fields in Wyoming, USA. We further tested whether the altered plant communities within reclaimed areas provided benefits to deer mice, by assessing multiple fitness indices. Deer mouse density increased with surrounding reclaimed area. Powder tracking and dietary analyses confirmed that mice moved through and consumed plant species found exclusively within reclaimed areas. Concomitant fitness metrics of mice, however, were neutrally or negatively related to the amount of surrounding reclaimed area. Mice therefore did not derive any apparent fitness benefits associated with living near reclaimed areas, despite the presence of novel food resources, indicating that increased abundance may be a product of mice dispersing toward reseeded soils. Our study contributes mechanistic insights into the complexities of how human-induced changes to landscapes can influence community dynamics. Minimizing total habitat disturbed during construction, expediting reclamation practices, and using only native and regionally-local seed mixes would likely help minimize increases in synanthropic rodent predators within energy fields. More efficient restoration of disturbed habitat, moreover, may help ameliorate altered predator-prey relationships that affect the success of sensitive species.

Wyoming↗

USGS2024

Adaptation and Response in Drylands (ARID): Community insights for scoping a NASA terrestrial ecology field campaign in drylands

Dryland ecosystems cover 40% of our planet's land surface, support billions of people, and are responding rapidly to climate and land use change. These expansive systems also dominate core aspects of Earth's climate, storing and exchanging vast amounts of water, carbon, and energy with the atmosphere. Despite their indispensable ecosystem services and high vulnerability to change, drylands are one of the least understood ecosystem types, partly due to challenges studying their heterogeneous landscapes and misconceptions that drylands are unproductive “wastelands.” Consequently, inadequate understanding of dryland processes has resulted in poor model representation and forecasting capacity, hindering decision making for these at-risk ecosystems. NASA satellite resources are increasingly available at the higher resolutions needed to enhance understanding of drylands' heterogeneous spatiotemporal dynamics. NASA's Terrestrial Ecology Program solicited proposals for scoping a multi-year field campaign, of which Adaptation and Response in Drylands (ARID) was one of two scoping studies selected. A primary goal of the scoping study is to gather input from the scientific and data end-user communities on dryland research gaps and data user needs. Here, we provide an overview of the ARID team's community engagement and how it has guided development of our framework. This includes an ARID kickoff meeting with over 300 participants held in October 2023 at the University of Arizona to gather input from data end-users and scientists. We also summarize insights gained from hundreds of follow-up activities, including from a tribal-engagement focused workshop in New Mexico, conference town halls, intensive roundtables, and international engagements.

Earth's Future↗

USGS2023

Evidence for density-dependent effects on body composition of a large omnivore in a changing Greater Yellowstone Ecosystem

Understanding the density-dependent processes that drive population demography in a changing world is critical in ecology, yet measuring performance–density relationships in long-lived mammalian species demands long-term data, limiting scientists' ability to observe such mechanisms. We tested performance–density relationships for an opportunistic omnivore, grizzly bears ( Ursus arctos , Linnaeus, 1758) in the Greater Yellowstone Ecosystem, with estimates of body composition (lean body mass and percent body fat) serving as indicators of individual performance over two decades (2000–2020) during which time pronounced environmental changes have occurred. Several high-calorie foods for grizzly bears have mostly declined in recent decades (e.g., whitebark pine [ Pinus albicaulis , Engelm, 1863]), while increasing human impacts from recreation, development, and long-term shifts in temperatures and precipitation are altering the ecosystem. We hypothesized that individual lean body mass declines as population density increases (H1), and that this effect would be more pronounced among growing individuals (H2). We also hypothesized that omnivory helps grizzly bears buffer energy intake from changing foods, with body fat levels being independent from population density and environmental changes (H3). Our analyses showed that individual lean body mass was negatively related to population density, particularly among growing-age females, supporting H1 and partially H2. In contrast, population density or sex had little effect on body fat levels and rate of accumulation, indicating that sufficient food resources were available on the landscape to accommodate successful use of shifting food sources, supporting H3. Our results offer important insights into ecological feedback mechanisms driving individual performances within a population undergoing demographic and ecosystem-level changes. However, synergistic effects of continued climate change and increased human impacts could lead to more extreme changes in food availability and affect observed population resilience mechanisms. Our findings underscore the importance of long-term studies in protected areas when investigating complex ecological relationships in an increasingly anthropogenic world.

Idaho, Montana, Wyoming↗

USGS2017

Lake Ontario benthic prey fish assessment, 2016

Benthic prey fishes are a critical component of the Lake Ontario food web, serving as energy vectors from benthic invertebrates to native and introduced piscivores. Beginning in 1978, Lake Ontario benthic prey fishes were assessed using bottom trawls collected from the lake’s south shore (depth range: 8 – 150 m). Historically, the survey targeted the then dominant species, Slimy Sculpin, however in 2015, the Benthic Prey Fish Survey was cooperatively expanded to a whole-lake survey, to address resource management information needs related to Round Goby, Deepwater Sculpin, and nearshore native fishes. In 2016, 142 trawls were collected at 18 transects, and spanned depths from 6 – 225 m. Trawl catches indicated the benthic and demersal prey fish community was dominated by Round Goby, however the proportional importance of native Deepwater Sculpin is increasing. Species-specific assessments found lake-wide Round Goby density (~600 fish per hectare) was slightly lower in 2016 relative to 2015. Deepwater Sculpin density has generally increased since 2004. In 2016 their estimated density was greater than 100 fish per hectare. Slimy Sculpin density (15 fish/ha) was similar to the past 3 years. Catches of juvenile Slimy Sculpin continue to be low relative to historic catches and the timing of their decline coincides with the proliferation of Round Goby. Additionally, we found a strong negative relationship between trawl catches of Round Goby and near-shore native benthic and demersal fishes such as Trout-perch, Johnny Darter and Spottail Shiner. The introduction of Round Goby and the reappearance of native Deepwater Sculpin have shaped the Lake Ontario benthic prey fish community.

Lake Ontario↗

USGS2017

Critical mineral resources of the United States—An introduction

Many changes have taken place in the mineral resource sector since the publication by the U.S. Geological Survey of Professional Paper 820, “United States Mineral Resources,” which is a review of the long-term United States resource position for 65 mineral commodities or commodity groups. For example, since 1973, the United States has continued to become increasingly dependent on imports to meet its demands for an increasing number of mineral commodities. The global demand for mineral commodities is at an alltime high and is expected to continue to increase, and the development of new technologies and products has led to the use of a greater number of mineral commodities in increasing quantities to the point that, today, essentially all naturally occurring elements have several significant industrial uses. Although most mineral commodities are present in sufficient amounts in the earth to provide adequate supplies for many years to come, their availability can be affected by such factors as social constraints, politics, laws, environmental regulations, land-use restrictions, economics, and infrastructure. This volume presents updated reviews of 23 mineral commodities and commodity groups viewed as critical to a broad range of existing and emerging technologies, renewable energy, and national security. The commodities or commodity groups included are antimony, barite, beryllium, cobalt, fluorine, gallium, germanium, graphite, hafnium, indium, lithium, manganese, niobium, platinum-group elements, rare-earth elements, rhenium, selenium, tantalum, tellurium, tin, titanium, vanadium, and zirconium. All these commodities have been listed as critical and (or) strategic in one or more of the recent studies based on assessed likelihood of supply interruption and the possible cost of such a disruption to the assessor. For some of the minerals, current production is limited to only one or a few countries. For many, the United States currently has no mine production or any significant identified resources and is largely dependent on imports to meet its needs. As a result, the emphasis in this volume is on the global distribution and availability of each mineral commodity. The environmental issues related to production of each mineral commodity, including current mitigation and remediation approaches to deal with these challenges, are also addressed. This introductory chapter provides an overview of the mineral resource classifications, terms, and definitions used in this volume. A review of the history of the use and meaning of the term “critical” minerals (or materials) is included as an appendix to the chapter.

Professional Paper↗

USGS2014

Lithium: for harnessing renewable energy

Lithium, which has the chemical symbol Li and an atomic number of 3, is the first metal in the periodic table. Lithium has many uses, the most prominent being in batteries for cell phones, laptops, and electric and hybrid vehicles. Worldwide sources of lithium are broken down by ore-deposit type as follows: closed-basin brines, 58%; pegmatites and related granites, 26%; lithium-enriched clays, 7%; oilfield brines, 3%; geothermal brines, 3%; and lithium-enriched zeolites, 3% (2013 statistics). There are over 39 million tons of lithium resources worldwide. Of this resource, the USGS estimates there to be approximately 13 million tons of current economically recoverable lithium reserves. To help predict where future lithium supplies might be located, USGS scientists study how and where identified resources are concentrated in the Earth’s crust, and they use that knowledge to assess the likelihood that undiscovered resources also exist.

Fact Sheet↗