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At least 919 records · Page 51Linked to original sources
USGS2015

Laboratory investigations of African Pouched Rats ( Cricetomys gambianus ) as a potential reservoir host species for Monkeypox Virus

Monkeypox is a zoonotic disease endemic to central and western Africa, where it is a major public health concern. Although Monkeypox virus (MPXV) and monkeypox disease in humans have been well characterized, little is known about its natural history, or its maintenance in animal populations of sylvatic reservoir(s). In 2003, several species of rodents imported from Ghana were involved in a monkeypox outbreak in the United States with individuals of three African rodent genera ( Cricetomys , Graphiurus , Funisciurus ) shown to be infected with MPXV. Here, we examine the course of MPXV infection in Cricetomys gambianus (pouched Gambian rats) and this rodent species’ competence as a host for the virus. We obtained ten Gambian rats from an introduced colony in Grassy Key, Florida and infected eight of these via scarification with a challenge dose of 4X10 4 plaque forming units (pfu) from either of the two primary clades of MPXV: Congo Basin (C-MPXV: n = 4) or West African (W-MPXV: n = 4); an additional 2 animals served as PBS controls. Viral shedding and the effect of infection on activity and physiological aspects of the animals were measured. MPXV challenged animals had significantly higher core body temperatures, reduced activity and increased weight loss than PBS controls. Viable virus was found in samples taken from animals in both experimental groups (C-MPXV and W-MPXV) between 3 and 27 days post infection (p.i.) (up to 1X10 8 pfu/ml), with viral DNA found until day 56 p.i. The results from this work show that Cricetomys gambianus (and by inference, probably the closely related species, Cricetomys emini ) can be infected with MPXV and shed viable virus particles; thus suggesting that these animals may be involved in the maintenance of MPXV in wildlife mammalian populations. More research is needed to elucidate the epidemiology of MPXV and the role of Gambian rats and other species.

PLoS Neglected Tropical Diseases↗
USGS2011

Wyoming groundwater-quality monitoring network

A wide variety of human activities have the potential to contaminate groundwater. In addition, naturally occurring constituents can limit the suitability of groundwater for some uses. The State of Wyoming has established rules and programs to evaluate and protect groundwater quality based on identified uses. The Wyoming Groundwater-Quality Monitoring Network (WGQMN) is a cooperative program between the U.S. Geological Survey (USGS) and the Wyoming Department of Environmental Quality (WDEQ) and was implemented in 2009 to evaluate the water-quality characteristics of the State's groundwater. Representatives from USGS, WDEQ, U.S. Environmental Protection Agency (USEPA), Wyoming Water Development Office, and Wyoming State Engineer's Office formed a steering committee, which meets periodically to evaluate progress and consider modifications to strengthen program objectives. The purpose of this fact sheet is to describe the WGQMN design and objectives, field procedures, and water-quality analyses. USGS groundwater activities in the Greater Green River Basin also are described.

Wyoming↗
USGS2007

Applying radar technology to migratory bird conservation and management: Strengthening and expanding a collaborative

Executive Summary Understanding the factors affecting migratory bird and bat populations during all three phases of their life cycle—breeding, nonbreeding, and migration—is critical to species conservation planning. This includes the need for information about these species’ responses to natural challenges, as well as information about the effects of human activities and structures. Habitats and other resources critical to migrants during passage and stopover are being destroyed, degraded, and threatened by human activities. Birds and bats are also uniquely susceptible to human use of the airspace. Wind turbines, communication and power transmission towers, and other tall structures, known to cause bird and bat mortality, are being erected or proposed in increasing numbers across the country. In addition, the potential for bird/aircraft collisions poses human safety threats. Management and regulatory agencies, conservation organizations, and industry currently lack the information they need to meet their missions and statutory responsibilities. The biological data available from various radar technologies offer a unique opportunity to learn more about the spatiotemporal distribution patterns, flight characteristics, and habitat use of “aero-fauna.” Recognizing the opportunities presented by radar technologies, the U.S. Geological Survey (USGS), the U.S. Fish and Wildlife Service (USFWS), and university partners collaborated first on individual projects and then in a broader, informal “collaborative” to coordinate their radar-related research and work together to develop the suite of products needed for conservation of birds and bats. Having produced two summary documents (Sojda and others, 2005; Ruth and others, 2005), the next objective was to convene a workshop for researchers, management and regulatory agencies, and other interested parties. The focus of this initial workshop was on strengthening the existing USGS-USFWS-university partnership and expanding the “collaborative” to include new Federal agency partners. The subject matter was centered on discussing available technologies, appropriate applications, management-related needs, and ways to strengthen collaborative research and conservation efforts. The workshop opened with presentations about the history of the “radar collaborative,” a description of the workshop objectives and focuses, and a summary of resource management and regulatory needs. Scientific presentations describing current research projects or subjects followed, given by USGS scientists, as well as scientists from other Federal agencies, academia, conservation and ornithological organizations, and a private contracting firm. Presenters addressed a wide variety of management issues including siting of wind-power facilities, bird/aircraft collisions, effects of hurricanes Katrina and Rita on bird migration, bird use of Conservation Reserve Program land, defining bird migration patterns at a broad regional scale, and associating migrant birds with their stopover habitats. Presentations described a variety of radar technologies including NEXRAD weather surveillance radar, modified mobile marine radar, military tracking radar, pencil beam radar, and dual polarization radar, as well as complementary techniques and analysis methods such as acoustic monitoring, thermal imaging, artificial intelligence, and individual-based modeling. Key issues, themes, and questions identified during the open discussions that followed fell into five main categories: (1) agency needs and challenges; (2) radar technology and applications—technical questions and issues; (3) tools and resources for managers and researchers; (4) standardization of protocols; and (5) collaborative opportunities. Participants identified the following management, regulatory, or business issues facing them which may be addressed with radar technologies: tall structures; wind turbines; identification and protection of key habitats; assessment of management activities; and bird/aircraft strikes. Participants frequently expressed the need for specific information about which radar technologies are best used for answering particular questions. User groups emphasized the importance of clear, defensible scientific information on which they can base their activities. In turn, researchers emphasized their need for clearly defined, specific questions from managers so that they can design and conduct the required research. Discussions about technical issues requiring further research and collaboration included target identity, ground-truthing, linking migrants to habitat, and standardized protocols for applied research. Workshop participants identified and endorsed a series of seven action items that would promote collaboration and begin to address key issues identified at the workshop: Action Item #1 : Establish a working subgroup to address large-scale surveillance radar standardization issues. Action Item #2 : Establish a working subgroup to address small-scale radar standardization issues. Action Item #3 : Bring management and regulatory agencies together to identify the three most important information needs for each key management issue relating to radar technologies. Action Item #4 : Develop Fact Sheet(s) to provide information about radar technology applications to migratory bird and bat conservation issues. Action Item #5 : Create a “radar collaborative” Website to provide information about radar biology applications, contacts, publications, and so forth. Action Item #6 : Formalize and expand the USGS-USFWS “radar collaborative.” Action Item #7 : Advance basic research, such as target identity and validation, which will support and improve our abilities to apply radar technologies to conservation objectives. There was considerable interest in expanding the “radar collaborative” to include those agencies, organizations, and industries represented at the workshop. It was felt that the publication of the workshop proceedings, implementation of action items, and additional future meetings or workshops will be crucial in strengthening the “radar collaborative” effort and promoting the use of these valuable technologies for conserving migratory species.

Open-File Report↗
USGS2020

Western purple martin (Progne subis arboricola) occurrence on the Siuslaw National Forest, Summer 2019

The western subspecies of the purple martin ( Progne subis arboricola ) is currently listed as a “critically” sensitive species in four ecoregions of western Oregon: Coast Range, Klamath Mountains, West Cascades, and Willamette Valley (Oregon Department of Fish and Wildlife, 2019). Importantly distinct from the abundant and widespread eastern subspecies ( Progne subis subis ), the western subspecies is of particular concern to Federal forest managers. Whereas the eastern subspecies is almost entirely dependent on artificial human-provided housing, the western subspecies continues to rely on natural cavities for nesting habitat (Bettinger, 2003). Accurate estimates of the regional abundance of the western purple martin are difficult to obtain; the most recent statewide census for Oregon, conducted in 2005, estimated the population at 1,100 pairs (Western Purple Martin Working Group, 2010). Several factors, including a small population size, loss of breeding habitat, and reductions in the number of suitable nesting sites have put populations of the western purple martin at risk throughout much of the Pacific Northwest region (Rockwell, 2019).

Oregon↗
USGS2022

Characterization of and temporal changes in groundwater quality of the Upper Black Squirrel Creek Basin, El Paso County, Colorado, 2018–20

In 2018–20, the U.S. Geological Survey, in cooperation with Upper Black Squirrel Creek Ground Water Management District, sampled 48 wells for Phase III of a multiphase plan investigating groundwater quality in the alluvial aquifer of the Upper Black Squirrel Creek Basin (UBSB), El Paso County, Colorado. Results for samples collected from October to December each year were used to assess spatial and temporal changes in groundwater quality and to differentiate sources of nitrate. Groundwater was predominantly classified as mixed-cation and mixed-anion water type in the aquifer, with variable chemistry along the periphery. Concentrations of constituents in groundwater were generally less than regulatory standards, except for nitrate in four wells. Isotopes of nitrogen and oxygen in nitrate identified four different potential sources or processes affecting nitrate in the alluvial aquifer: naturally occurring nitrate from soils, nitrate from animal and (or) human waste, and an unknown source, along with evidence of denitrification. Pharmaceutical compounds and personal-care products were detected in seven wells, with three wells having multiple detections. Stable isotopes of water indicated variability in seasonality of recharge throughout the UBSB alluvial aquifer. Nitrate concentrations from the 1984 study and the 1996 study were compared to the more recent concentrations in the 2013 study and the 2018–20 study. The northern one-third of the UBSB alluvial aquifer had a statistically significant increase in nitrate concentration from the 2013 study to the 2018–20 study, but no change was shown from the 1984 study to the 1996 study. The opposite was found true for the southern two-thirds of the UBSB alluvial aquifer with no statistically significant difference in nitrate concentration from the 2013 study to the 2018–20 study. Analysis of temporal changes indicated an increase in median and maximum nitrate concentrations from the 2013 study to the 2018–20 study throughout the UBSB alluvial aquifer. Continued sampling of wells in the UBSB would be beneficial to better determine temporal changes in groundwater quality, characterize human effects on water quality, and understand characteristics of the alluvial aquifer pertaining to sustainability of the resource.

Colorado↗
USGS1993

Ground-water resources of the Caguas-Juncos Valley, Puerto Rico

?The Caguas-Juncos valley, which occupies an area of 35 square miles in east-central Puerto Rico, is underlain by the largely unconfined alluvial aquifer. Withdrawals from this aquifer for public water supply and for agricultural, industrial, and domestic water uses totalled about 3.0 million gallons per day in 1988. Some wells in the valley yield as much as 310 gallons per minute from the alluvial deposits along Rio Gurabo near Gurabo and near Juncos. Wells used at dairy farms in the area commonly yield about 30 gallons per minute. The potentiometric surface of the alluvial aquifer varies seasonally and generally is highest near the end of December and lowest in April. Transmissivity of the alluvial aquifer, estimated from specific capacity and slug test data, ranges from 65 to 4,800 feet squared per day. The estimated specific yield of the water-table is about 10 to 15 percent. The amount of water stored in the aquifer is estimated to be about 122,000 acre-feet. Analyses of ground-water samples revealed the presence of two distinct problems-- high natural concentrations of iron and manganese, and localized areas of human- related contamination scattered throughout the valley. The ground water is a calcium-bicarbonate type and typically has dissolved solids concentrations of less than 500 milligrams per liter.

Puerto Rico↗
USGS1999

Water-quality assessment of the Cook Inlet Basin, Alaska — Environmental setting

The Cook Inlet Basin in Alaska is one of 59 study units selected for study for water-quality assessment as part of the U.S. Geological Survey's National Water-Quality Assessment program. The Cook Inlet Basin study unit encompasses the fresh surface and ground waters in the 39,325 square-mile area that drains to Cook Inlet, but does not include the marine waters of Cook Inlet. This report describes the natural factors (climate, physiography, geology, soils, land cover) and the human factors (population, land use, water use) that affect water quality, which is the first step in designing and conducting a multidisciplinary regional water-quality assessment. The surface- and ground-water hydrology, and the aquatic ecosystems of the Cook Inlet Basin are described. The report provides an overview of existing water-quality conditions and summarizes the results of selected water-quality studies of the basin.

Alaska↗
USGS2023

Facing our freshwater crisis via fluid and agile communication: A grand challenge

Earth has been labeled the blue planet because of its abundance of water that covers most of its surface, but the majority is salt water in our oceans. Oceans account for ~352 million km 2 or 69% of the planet's surface, land for 150 million km 2 or 29%, and fresh water for 9 million km 2 or 2% ( Shiklomanov, 2000 ). Most of the fresh water is locked away in glaciers and ice sheets on Greenland and Antarctica, with less than a third accessible to biota ( Shiklomanov, 2000 ). This miniscule fraction of fresh water is our most precious natural resource, the foundation for life in terrestrial environments, and humanity depends on it, but the resource faces enormous threats. My aim in this brief editorial is to define the freshwater resource, succinctly summarize the major threats it faces, and underscore recent calls for conservation. My review is cursory, but I call attention to various recent exhaustive reviews. I end with my views on how journals can help advance global freshwater conservation efforts.

Frontiers in Freshwater Science↗
USGS2018

Aligning environmental management with ecosystem resilience: a First Foods example from the Confederated Tribes of the Umatilla Indian Reservation, Oregon, USA

The concept of “reciprocity” between humans and other biota arises from the creation belief of the Confederated Tribes of the Umatilla Indian Reservation (CTUIR). The concept acknowledges a moral and practical obligation for humans and biota to care for and sustain one another, and arises from human gratitude and reverence for the contributions and sacrifices made by other biota to sustain human kind. Reciprocity has become a powerful organizing principle for the CTUIR Department of Natural Resources, fostering continuity across the actions and policies of environmental management programs at the CTUIR. Moreover, reciprocity is the foundation of the CTUIR “First Foods” management approach. We describe the cultural significance of First Foods, the First Foods management approach, a resulting management vision for resilient and functional river ecosystems, and subsequent shifts in management goals and planning among tribal environmental staff during the first decade of managing for First Foods. In presenting this management approach, we highlight how reciprocity has helped align human values and management goals with ecosystem resilience, yielding management decisions that benefit individuals and communities, indigenous and nonindigenous, as well as human and nonhuman. We further describe the broader applicability of reciprocity-based approaches to natural resource management.

Oregon↗
USGS1993

Processes affecting coastal wetland loss in the Louisiana deltaic plain

Nowhere are the problems of coastal wetland loss more serious and dramatic than in the Mississippi River deltaic plain region of south-central Louisiana. In that area, rates of shoreline erosion of 20 m.yr and loss of land area of up to 75 km/yr result from a complex combination of natural (delta switching, subsidence, sea-level rise, storms) and human (flood control, navigation, oil and gas development, land reclamation) factors. The U.S. Geological Survey (USGS), as part of the National Coastal Geology Program, has undertaken joint filed investigations with Federal, State, and university partners. The objective of these long-term studies is to gather and interpret baseline information in order to improve our scientific understanding of the critical processes and responses responsible for creation, maintenance, and deterioration of coastal wetlands.

Conference Paper↗
USGS2010

Groundwater sampling

Groundwater is protected in most areas as it is a primary source of drinking water. In the United States, 50% of the population relies on groundwater supplies (Reilly et al., 2008). Groundwater sampling in the United States became commonplace in the 20th century as contaminated water resources became apparent and a growing public concern emerged to protect water resources. In response to this concern, the U.S. government mandated a study in which scientists identified six categories of groundwater contaminant sources (OTA, 1984): Category 1-sources designed to discharge substances (e.g., injection well) Category 2-sources designed to store, treat, and/or dispose of substances; discharge through unplanned release (e.g., landfills) Category 3-sources designed to retain substances during transport or trans-mission (e.g., pipelines) Category 4-sources discharging as consequence of other planned activities (e.g., pesticide application) Category 5-sources providing conduit or inducing discharge through altered flow patterns (e.g., construction excavation) Category 6-naturally occurring sources whose discharge is created and/or exacerbated by human activity (e.g., salt water intrusion).

Book chapter↗
USGS2021

Arsenic release to the environment from hydrocarbon production, storage, transportation, use and waste management

Arsenic (As) is a toxic trace element with many sources, including hydrocarbons such as oil, natural gas, oil sands, and oil- and gas-bearing shales. Arsenic from these hydrocarbon sources can be released to the environment through human activities of hydrocarbon production, storage, transportation and use. In addition, accidental release of hydrocarbons to aquifers with naturally occurring (geogenic) As can induce mobilization of As to groundwater through biogeochemical reactions triggered by hydrocarbon biodegradation. In this paper, we review the occurrence of As in different hydrocarbons and the release of As from these sources into the environment. We also examine the occurrence of As in wastes from hydrocarbon production, including produced water and sludge. Last, we discuss the potential for As release related to waste management, including accidental or intentional releases, and recycling and reuse of these wastes.

Journal of Hazardous Materials↗
USGS2022

Exploring and mitigating plague for One Health purposes

Purpose of Review In 2020, the Appropriations Committee for the U.S. House of Representatives directed the CDC to develop a national One Health framework to combat zoonotic diseases, including sylvatic plague, which is caused by the flea-borne bacterium Yersinia pestis . This review builds upon that multisectoral objective. We aim to increase awareness of Y. pestis and to highlight examples of plague mitigation for One Health purposes (i.e., to achieve optimal health outcomes for people, animals, plants, and their shared environment). We draw primarily upon examples from the USA, but also discuss research from Madagascar and Uganda where relevant, as Y. pestis has emerged as a zoonotic threat in those foci. Recent Findings Historically, the bulk of plague research has been directed at the disease in humans. This is not surprising, given that Y. pestis is a scourge of human history. Nevertheless, the ecology of Y. pestis is inextricably linked to other mammals and fleas under natural conditions. Accumulating evidence demonstrates Y. pestis is an unrelenting threat to multiple ecosystems, where the bacterium is capable of significantly reducing native species abundance and diversity while altering competitive and trophic relationships, food web connections, and nutrient cycles. In doing so, Y. pestis transforms ecosystems, causing “shifting baselines syndrome” in humans, where there is a gradual shift in the accepted norms for the condition of the natural environment. Eradication of Y. pestis in nature is difficult to impossible, but effective mitigation is achievable; we discuss flea vector control and One Health implications in this context. Summary There is an acute need to rapidly expand research on Y. pestis , across multiple host and flea species and varied ecosystems of the Western US and abroad, for human and environmental health purposes. The fate of many wildlife species hangs in the balance, and the implications for humans are profound in some regions. Collaborative multisectoral research is needed to define the scope of the problem in each epidemiological context and to identify, refine, and implement appropriate and effective mitigation practices.

Current Tropical Medicine Reports↗
USGS1999

Selected elements and organic chemicals in bed sediment and fish tissue of the Tualatin River basin, Oregon, 1992-96

A variety of elements and organic compounds have entered the environment as a result of human activities. Such substances find their way to aquatic sediments from direct discharges to waterways, atmospheric emissions, and runoff. Some of these chemicals are known to harm fish or wildlife, either by direct toxicity, by reducing viability, or by limiting reproductive success. In aquatic systems, sediments become the eventual sink for most of these chemicals. Analyzing the sediments provides a first step in a chemical inventory that can lead to an assessment of potential biological impacts (Kennicutt and others, 1994). Many elements (iron, aluminum, calcium, and others) enter the environment from the natural weathering of rock. Additional amounts of elements have been contributed by human activities such as mining, metals production and processing, fossil fuel combustion, municipal waste incineration, and transportationrelated sources. The environmental presence of some elements, such as lead and mercury, is almost entirely due to human activity. Lead is often associated with the use of leaded gasoline and from the manufacture and disposal of lead storage batteries. Mercury was used historically in a variety of industrial processes and as a pesticide. Nriagu and Pacyna (1998) concluded that human activity is the “most important element in the global biogeochemical cycling of the trace metals.” The number of organic compounds in existence and their total production has more than tripled in the last century. Many of these compounds enter the environment directly as pesticides; others are inadvertently discharged. Some organic compounds have natural sources. Three general classes of organic compounds will be discussed: organochlorine compounds, polyaromatic hydrocarbons, and phthalates. Almost all organochlorine compounds are manmade. Many are pesticides that were used widely in the 1950s–60s (DDT and chlordanes, for example). Use of most organochlorine pesticides was restricted or banned in the United States in the 1970s–80s. Polychlorinated biphenyls (PCBs) are also organochlorine compounds; they were used for a variety of applications, but most commonly as insulators in electrical transformers and other equipment. In general, organochlorine compounds degrade very slowly in the environment and therefore, are routinely found in environmental samples, despite the fact that they are no longer used in the United States. They are hydrophobic that is they do not dissolve readily in water and, in aquatic systems, are almost exclusively associated with sediments or tissue. Because these compounds cause a variety of adverse health effects in wildlife, the U.S. Environmental Protection Agency (USEPA) has listed many as priority pollutants. Organochlorine compounds also have been implicated as endocrine disrupters— chemicals that can interfere with the normal function of hormones. Polyaromatic hydrocarbons (PAHs) are found in sediments throughout the world (Hites and others, 1980). Their presence is thought to be primarily anthropogenic. PAHs occur naturally in petroleum products and also are produced during combustion. They enter the environment from fuel spills, tar coatings, coal and other fossil fuel usage, road dust, and from the atmospheric deposition of combustion products (Prahl and others, 1984; Wakeham and others, 1980). Urban areas often have high concentrations of PAHs because of transportation-related sources (vehicle exhaust, paving materials, and releases of fuel or oil). Natural sources, such as forest fires, may contribute small amounts of PAHs. Several PAHs are known carcinogens (benzo[a]pyrene, for example); 16 are listed as USEPA priority pollutants. Phthalate compounds are often associated with urban areas. They are used in a wide variety of industrial applications and in inks, adhesives, resins, and as plasticizers (chemicals that increase the flexibility of plastics). In aquatic systems, phthalates are found mostly in sediments where they degrade very slowly. Phthalates are thought to be endocrine disrupters; Jobling and others (1995) found that some phthalates were weakly estrogenic. USEPA considers some phthalates to be possible carcinogens. This report describes the results of a reconnaissance survey of elements and organic compounds found in bed sediment and fish tissue in streams of the Tualatin River Basin. The basin is in northwestern Oregon to the west of the Portland metropolitan area (fig. 1). The Tualatin River flows for about 80 miles, draining an area of about 712 square miles, before it enters the Willamette River. Land use in the basin changes from mostly forested in the headwaters, to mixed forest and agriculture, to predominately urban. The basin supports a growing population of more than 350,000 people, most of whom live in lower parts of the basin. Water quality in the Tualatin River and its tributaries is expected to be affected by the increasing urbanization of the basin.

Oregon↗
USGS2009

The Ecology of Parasite-Host Interactions at Montezuma Well National Monument, Arizona - Appreciating the Importance of Parasites

Although parasites play important ecological roles through the direct interactions they have with their hosts, historically that fact has been underappreciated. Today, scientists have a growing appreciation of the scope of such impacts. Parasites have been reported to dominate food webs, alter predator-prey relationships, act as ecosystem engineers, and alter community structure. In spite of this growing awareness in the scientific community, parasites are still often neglected in the consideration of the management and conservation of resources and ecosystems. Given that at least half of the organisms on earth are probably parasitic, it should be evident that the ecological functions of parasites warrant greater attention. In this report, we explore different aspects of parasite-host relationships found at a desert spring pond within Montezuma Well National Monument, Arizona. In three separate but related chapters, we explore interactions between a novel amphipod host and two parasites. First, we identify how host behavior responds to this association and how this association affects interactions with both invertebrate non-host predators and a vertebrate host predator. Second, we look at the human dimension, investigating how human recreation can indirectly affect patterns of disease by altering patterns of vertebrate host space use. Finally - because parasites and diseases are of increasing importance in the management of wildlife species, especially those that are imperiled or of management concern - the third chapter argues that research would benefit from increased attention to the statistical analysis of wildlife disease studies. This report also explores issues of statistical parasitology, providing information that may better inform those designing research projects and analyzing data from studies of wildlife disease. In investigating the nature of parasite-host interactions, the role that relationships play in ecological communities, and how human activities alter these associations, scientists usually make inferences by methods of statistical hypotheses testing. This type of hypothesis testing places additional importance on the analysis and interpretation of parasite-host interactions. We address these ideas in this report, focusing on the following questions: (1) How do two parasites with complex life cycles alter the behavior of a novel amphipod host, and how do host and non-host predators respond to infected amphipod prey? (2) Does human recreation affect spatial patterns of infection in an otherwise natural ecosystem? (3) How is hypothesis-testing applied in studies of wildlife disease? (4) What conclusions can we make about the relative usefulness of these methodologies? and (5) How can the analysis and interpretation of wildlife disease studies be improved? Each chapter of this report contains its own literature-cited section, with tables included in appendixes at the end of the full report.

Open-File Report↗
USGS2019

Perspective: Developing flow policies to balance the water needs of humans and wetlands requires a landscape scale approach inclusive of future scenarios and multiple timescales

Maintenance of the natural flow regime is essential for continued wetland integrity; however, the flow regime is greatly influenced by both natural and anthropogenic forces. Wetlands may be particularly susceptible to altered flow regimes as they are directly impacted by water flows at a variety of time scales. In Puerto Rico, contemporary water management is decreasing freshwater recharge to wetlands and contributes to the salinization of important coastal wetlands as sea levels rise. Further, downscaled climate models predict an increase in drought frequency, intensity, and duration by mid-century. Conflicts over water allocation seem imminent between human and ecological needs. Current minimum flow policies are insufficient given the complexities of ecosystem processes and the changes in precipitation patterns and sea level rise that are expected in the future. Improved flow policies need to be established that reflect the functional relationships between specific representative ecological resources and components of the natural flow regime across all relevant time scales. Similarly, flow policies need to be developed within a landscape scale to implicitly address the socio-ecological trade-offs as well as the complexities of water management. Multi-disciplinary collaborations will be essential for increasing our resiliency to anticipated future changes.

Wetlands↗
USGS2009

The Drenchwater deposit, Alaska: An example of a natural low pH environment resulting from weathering of an undisturbed shale-hosted Zn-Pb-Ag deposit

The Drenchwater shale-hosted Zn-Pb-Ag deposit and the immediate vicinity, on the northern flank of the Brooks Range in north-central Alaska, is an ideal example of a naturally low pH system. The two drainages, Drenchwater and False Wager Creeks, which bound the deposit, differ in their acidity and metal contents. Moderately acidic waters with elevated concentrations of metals (pH ??? 4.3, Zn ??? 1400 ??g/L) in the Drenchwater Creek drainage basin are attributed to weathering of an exposed base-metal-rich massive sulfide occurrence. Stream sediment and water chemistry data collected from False Wager Creek suggest that an unexposed base-metal sulfide occurrence may account for the lower pH (2.7-3.1) and very metal-rich waters (up to 2600 ??g/L Zn, ??? 260 ??g/L Cu and ???89 ??g/L Tl) collected at least 2 km upstream of known mineralized exposures. These more acidic conditions produce jarosite, schwertmannite and Fe-hydroxides commonly associated with acid-mine drainage. The high metal concentrations in some water samples from both streams naturally exceed Alaska state regulatory limits for freshwater aquatic life, affirming the importance of establishing base-line conditions in the event of human land development. The studies at the Drenchwater deposit demonstrate that poor water quality can be generated through entirely natural weathering of base-metal occurrences, and, possibly unmineralized black shale.

Applied Geochemistry↗