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At least 847 records · Page 47Linked to original sources

USGS1997

Transboundary pollution: Persistent organochlorine pesticides in migrant birds of the Southwestern United States and Mexico

The hypothesis that migratory birds accumulate persistent organochlorine pesticides (POPs) during the winter in Latin America has been prevalent for many years, particularly since 1,1,1-trichloro-2,2–bis(p-chlorophenyl)ethane (DDT) was banned in the United States in 1972. It has been suggested that peregrine falcons ( Falco peregrinus ), black-crowned night herons ( Nycticorax nycticorax ), white-faced ibises ( Plegadis chihi ), various migratory waterfowl and shorebirds, and other avian species accumulate higher concentrations of POPs while on migration or on their wintering grounds in Latin America. Nonetheless, the data obtained thus far are limited, and there is no clear pattern to suggest that such accumulation occurs on a widespread basis. In this review wildlife contaminant studies conducted along the U.S.-Mexico border and throughout Mexico are discussed. The results for the most part seem to indicate that no major accumulation of 2,2-bis(p-chlorophenyl)-1,1-dichloroethylene) (DDE), the most persistent organochlorine compound, has occurred or been reported for most parts of Mexico. The majority of the DDE values in birds from Mexico were similar to those reported in birds from the southwestern United States during the same years. More work needs to be done, particularly in those cotton-producing areas of Mexico where DDT was applied heavily in the past (e.g., Chiapas and Michoacan). Because DDT is still used for malaria control and may still be used in agriculture in Chiapas, this state is probably the one where most migrant species would still be at a significant risk of increased accumulation of DDE and DDT.

Environmental Toxicology and Chemistry↗

USGS2024

Microplastic-mediated new mechanism of liver damage: From the perspective of the gut-liver axis

Microplastics (MPs) are environmental contaminants that are present in all environments and can enter the human body, accumulate in various organs, and cause harm through the ingestion of food, inhalation, and dermal contact. The connection between bowel and liver disease and the interplay between gut, liver, and flora has been conceptualized as the “gut-liver axis”. Microplastics can alter the structure of microbial communities in the gut and the liver can also be a target for microplastic invasion. Numerous studies have found that when MPs impair human health, they not only promote dysbiosis of the gut microbiota and disruption of the gut barrier but also cause liver damage. For this reason, the gut-liver axis provides a new perspective in understanding this toxic response. The cross-talk between MPs and the gut-liver axis has attracted the attention of the scientific community, but knowledge about whether MPs cause gut-liver interactions through the gut-liver axis is still very limited, and the effect of MPs on liver injury is not well understood. MPs can directly induce microbiota disorders and gut barrier dysfunction. As a result, harmful bacteria and metabolites in the gut enter the blood through the weak intestinal barrier (portal vein channel along the gut-liver axis) and reach the liver, causing liver damage (inflammatory damage, metabolic disorders, oxidative stress, etc.). This review provides an integrated perspective of the gut-liver axis to help conceptualize the mechanisms by which MP exposure induces gut microbiota dysbiosis and hepatic injury and highlights the connection between MPs and the gut-liver axis. Therefore, from the perspective of the gut-liver axis, targeting intestinal flora is an important way to eliminate microplastic liver damage.

Science of the Total Environment↗

USGS2001

Compilation of water-resources data and hydrogeologic setting for Brunswick County, North Carolina, 1933-2000

Water-resources data were compiled for Brunswick County, North Carolina, to describe the hydrologic conditions of the County. Hydrologic data collected by the U.S. Geological Survey as well as data collected by other governmental agencies and reviewed by the U.S. Geological Survey are presented. Data from four weather stations and two surface-water stations are summarized. Data also are presented for land use and land cover, soils, geology, hydrogeology, 12 continuously monitored ground-water wells, 73 periodically measured ground-water wells, and water-quality measurements from 39 ground-water wells. Mean monthly precipitation at the Longwood, Shallotte, Southport, and Wilmington Airport weather stations ranged from 2.19 to 7.94 inches for the periods of record, and mean monthly temperatures at the Longwood, Southport, and Wilmington Airport weather stations ranged from 43.4 to 80.1 degrees Fahrenheit for the periods of record. An evaluation of land-use and land-cover data for Brunswick County indicated that most of the County is either forested land (about 57 percent) or wetlands (about 29 percent). Cross sections are presented to illustrate the general hydrogeology beneath Brunswick County. Water-level data for Brunswick County indicate that water levels ranged from about 110 feet above mean sea level to about 22 feet below mean sea level. Chloride concentrations measured in aquifers in Brunswick County ranged from near 0 to 15,000 milligrams per liter. Chloride levels in the Black Creek and Cape Fear aquifers were measured at well above the potable limit for ground water of 250 milligrams per liter set by the U.S. Environmental Protection Agency for safe drinking water.

North Carolina↗

USGS1993

Earthquake locations determined by the Southern Alaska seismograph network for October 1971 through May 1989

This report describes the instrumentation and evolution of the U.S. Geological Survey’s regional seismograph network in southern Alaska, provides phase and hypocenter data for seismic events from October 1971 through May 1989, reviews the location methods used, and discusses the completeness of the catalog and the accuracy of the computed hypocenters. Included are arrival time data for explosions detonated under the Trans-Alaska Crustal Transect (TACT) in 1984 and 1985. The U.S. Geological Survey (USGS) operated a regional network of seismographs in southern Alaska from 1971 to the mid 1990s. The principal purpose of this network was to record seismic data to be used to precisely locate earthquakes in the seismic zones of southern Alaska, delineate seismically active faults, assess seismic risks, document potential premonitory earthquake phenomena, investigate current tectonic deformation, and study the structure and physical properties of the crust and upper mantle. A task fundamental to all of these goals was the routine cataloging of parameters for earthquakes located within and adjacent to the seismograph network. The initial network of 10 stations, 7 around Cook Inlet and 3 near Valdez, was installed in 1971. In subsequent summers additions or modifications to the network were made. By the fall of 1973, 26 stations extended from western Cook Inlet to eastern Prince William Sound, and 4 stations were located to the east between Cordova and Yakutat. A year later 20 additional stations were installed. Thirteen of these were placed along the eastern Gulf of Alaska with support from the National Oceanic and Atmospheric Administration (NOAA) under the Outer Continental Shelf Environmental Assessment Program to investigate the seismicity of the outer continental shelf, a region of interest for oil exploration. Since then the region covered by the network remained relatively fixed while efforts were made to make the stations more reliable through improved electronic instrumentation and strengthened antenna systems. The majority of the stations installed since 1980 were operated only temporarily (from one to several years) for special studies in various areas within the network. Due to reduced funding, the network was trimmed substantially in the summer of 1985 with the closure of 15 stations, 13 of which were located in and around the Yakataga seismic gap. To further reduce costs, two telephone circuits were dropped and multiple radio relays were installed in their place. This economy reduced the reliability of these telemetry links. In addition, data collection from the areas around Cordova and Yakutat was compromised by the necessity of relying on triggered event recording using PC-based systems (Rogers, 1993) that were not fully developed and which proved to be less reliable than anticipated. The principal means of recording throughout the time period of this catalog was 20-channel oscillographs on 16-mm film (Teledyne Geotech Develocorder, Model RF400 and 4000D). Initially one Develocorder was operated at the USGS Alaskan headquarters in Anchorage, but in 1972 recording was shifted to the National Oceanic and Atmospheric Administration (NOAA) Palmer Observatory (currently the West Coast and Alaska Tsunami Warning Center). The Develocorders were turned off at the end of May 1989, and after that time recording was done in digital format at the Geophysical Institute of the University of Alaska in Fairbanks (GIUA). Thus, this catalog covers the entire period of film recording.

Alaska↗

USGS2017

Food web conceptual model

This chapter describes a general model of food webs within tidal wetlands and represents how physical features of the wetland affect the structure and function of the food web. This conceptual model focuses on how the food web provides support for (or may reduce support for) threatened fish species. This model is part of a suite of conceptual models designed to guide monitoring of restoration sites throughout the San Francisco Estuary (SFE), but particularly within the Sacramento-San Joaquin Delta (Delta) and Suisun Marsh. The conceptual models have been developed based on the Delta Regional Ecosystem Restoration Implementation Plan (DRERIP) models, and are designed to aid in the identification and evaluation of monitoring metrics for tidal wetland restoration projects. Many tidal restoration sites in the Delta are being constructed to comply with environmental regulatory requirements associated with the operation of the Central Valley Project and State Water Project. These include the Biological Opinions for Delta Smelt (Hypomesus transpacificus) and salmonids (U.S. Fish and Wildlife Service 2008; National Marine Fisheries Service 2009), and the Incidental Take Permit for Longfin Smelt (Spirinchus thaleichthyes) (California Department of Fish and Wildlife 2009). These regulatory requirements are based on the hypothesis that the decline of listed fish species is due in part to a decline in productivity of the food web (phytoplankton and zooplankton in particular) or alterations in the food web such that production is consumed by other species in the Estuary (Sommer et al. 2007; Baxter et al. 2010; Brown et al. 2016a). Intertidal wetlands and shallow subtidal habitat can be highly productive, so restoring areas of tidal wetlands may result in a net increase in productivity that will provide food web support for these fish species. However, other factors such as invasive bivalves that reduce phytoplankton and zooplankton biomass and invasive predatory fishes that may compete with or prey upon listed fishes can limit the utility of tidal wetlands for food web support (Lucas and Thompson 2012; Herbold et al. 2014). This model utilizes information from the previous DRERIP models for Delta food webs (Durand 2008) and tidal wetlands (Kneib et al. 2008), an updated DRERIP model (Durand 2015), and the State of BayDelta Science 2016 review of recent Delta food web literature (Brown et al. 2016a).

Interagency Ecological Program Technical Report↗

USGS2001

A probabilistic model for silver bioaccumulation in aquatic systems and assessment of human health risks

Silver (Ag) is discharged in wastewater effluents and is also a component in a proposed secondary water disinfectant. A steady-state model was developed to simulate bioaccumulation in aquatic biota and assess ecological and human health risks. Trophic levels included phytoplankton, invertebrates, brown trout, and common carp. Uptake routes included water, food, or sediment. Based on an extensive review of the literature, distributions were derived for most inputs for use in Monte Carlo simulations. Three scenarios represented ranges of dilution and turbidity. Compared with the limited field data available, median estimates of Ag in carp (0.07-2.1 Iμg/g dry weight) were 0.5 to 9 times measured values, and all measurements were within the predicted interquartile range. Median Ag concentrations in biota were ranked invertebrates > phytoplankton > trout > carp. Biotic concentrations were highest for conditions of low dilution and low turbidity. Critical variables included Ag assimilation eficiency, specific feeding rate, and the phytoplankton bioconcentration factor. Bioaccumulation of Ag seems unlikely to result in txicity to aquatic biota and humans consuming fish. Although the highest predicted Ag concentrations in water (>200 ng/L) may pose chronic risks to early survival and development of salmonids and risks of argyria to subsistence fishers, these results occur under highly conservative conditions.

Environmental Toxicology and Chemistry↗

USGS1999

Water sediment, and nutrient budgets, and bathymetric survey of Old and New Gillespie Lakes, Macoupin County, Illinois, May 1996-April 1997; with a discussion of lake-management practices

The Gillespie Lakes system serves as a drinking water source for the town of Gillespie, Illinois, and is a major recreational focus for the area. As part of an investigation of a concern that the lakes are being adversely affected by excessive sediment and nutrient in flows, this report presents hydrologic, sediment, and nutrient budgets for Old Gillespie Lake and New Gillespie Lake, calculated by the U.S. Geological Survey with data collected during May 1996-April 1997 in cooperation with the Illinois Environmental Protection Agency and the city of Gillespie, Illinois. Bathymetric data also were collected in the two lakes to produce maps of the lake bed elevations. The influx of sediment, phosphorus, and nitrogen into Old Gillespie Lake during the study period was 4,063, 6.02, and 52.3 tons, respectively. Old Gillespie Lake retained 92 percent of the inflowing sediment (which agrees with theoretical calculations of trapping efficiency for Old Gillespie Lake), 84 percent of the inflowing phosphorus, and 87 percent of the inflowing nitrogen. The influx of sediment, phosphorus, and nitrogen into New Gillespie Lake during the study period was 4,792, 7.56, and 64.3 tons, respectively. Old Gillespie Lake retained 95 percent of the inflowing sediment (which agrees with theoretical calculations of trapping efficiency for New Gillespie Lake), 82 percent of the inflowing phosphorus, and 81 percent of the inflowing nitrogen. The loads per area of phosphorus and nitrogen to the Gillespie Lakes were 1.06 tons/mi 2 and 9.26 tons/mi 2 , respectively. For row crops of corn and soybeans, the literature reports ranges of loads per area of phosphorus of 0.15 to 1.43 tons/mi 2 and of nitrogen of 0.86 to 11.43 tons/mi 2 . Therefore, loads to the Gillespie Lakes are relatively high for the given cropping practices, and application of best management practices may substantially reduce the per area loads of these nutrients. Considering these loads and retention of sediment and nutrients, a review of basic lake management practices is presented and discussed. This review is presented to assist lake managers in the achievement of lake water-quality goals.

Macoupin County↗

USGS2013

A review of selected inorganic surface water quality-monitoring practices: are we really measuring what we think, and if so, are we doing it right?

Successful environmental/water quality-monitoring programs usually require a balance between analytical capabilities, the collection and preservation of representative samples, and available financial/personnel resources. Due to current economic conditions, monitoring programs are under increasing pressure to do more with less. Hence, a review of current sampling and analytical methodologies, and some of the underlying assumptions that form the bases for these programs seems appropriate, to see if they are achieving their intended objectives within acceptable error limits and/or measurement uncertainty, in a cost-effective manner. That evaluation appears to indicate that several common sampling/processing/analytical procedures (e.g., dip (point) samples/measurements, nitrogen determinations, total recoverable analytical procedures) are generating biased or nonrepresentative data, and that some of the underlying assumptions relative to current programs, such as calendar-based sampling and stationarity are no longer defensible. The extensive use of statistical models as well as surrogates (e.g., turbidity) also needs to be re-examined because the hydrologic interrelationships that support their use tend to be dynamic rather than static. As a result, a number of monitoring programs may need redesigning, some sampling and analytical procedures may need to be updated, and model/surrogate interrelationships may require recalibration.

Environmental Science & Technology↗

USGS2025

Pathways for potential exposure to onshore oil and gas wastewater: What we need to know to protect human health

Produced water is a chemically complex waste stream generated during oil and gas development. Roughly four trillion liters were generated onshore in the United States in 2021 (ALL Consulting, 2022, https://www.gwpc.org/wp-content/uploads/2021/09/2021_Produced_Water_Volumes.pdf ). Efforts are underway to expand historic uses of produced water to offset freshwater needs in water-stressed regions, avoid induced seismic activity associated with its disposal, and extract commodities. Understanding the potential exposures from current and proposed produced water uses and management practices can help to inform health-protective practices. This review summarizes what is known about potential human exposure to produced water from onshore oil and gas development in the United States. We synthesize 236 publications to create a conceptual model of potential human exposure that illustrates the current state of scientific inquiry and knowledge. Exposure to produced water can occur following its release to the environment through spills or leaks during its handling and management. Exposure can also arise from authorized releases, including permitted discharges to surface water, crop irrigation, and road treatment. Knowledge gaps include understanding the variable composition and toxicity of produced water released to the environment, the performance of treatment methods, migration pathways through the environment that can result in human exposure, and the significance of the exposures for human and ecosystem health. Reducing these uncertainties may help in realizing the benefits of produced water use while simultaneously protecting human health.

Environmental Health Perspectives↗

USGS2013

Alaska Geochemical Database, Version 2.0 (AGDB2)–Including “best value” data compilations for rock, sediment, soil, mineral, and concentrate sample mediaI

The Alaska Geochemical Database Version 2.0 (AGDB2) contains new geochemical data compilations in which each geologic material sample has one “best value” determination for each analyzed species, greatly improving speed and efficiency of use. Like the Alaska Geochemical Database (AGDB, http://pubs.usgs.gov/ds/637/) before it, the AGDB2 was created and designed to compile and integrate geochemical data from Alaska in order to facilitate geologic mapping, petrologic studies, mineral resource assessments, definition of geochemical baseline values and statistics, environmental impact assessments, and studies in medical geology. This relational database, created from the Alaska Geochemical Database (AGDB) that was released in 2011, serves as a data archive in support of present and future Alaskan geologic and geochemical projects, and contains data tables in several different formats describing historical and new quantitative and qualitative geochemical analyses. The analytical results were determined by 85 laboratory and field analytical methods on 264,095 rock, sediment, soil, mineral and heavy-mineral concentrate samples. Most samples were collected by U.S. Geological Survey personnel and analyzed in U.S. Geological Survey laboratories or, under contracts, in commercial analytical laboratories. These data represent analyses of samples collected as part of various U.S. Geological Survey programs and projects from 1962 through 2009. In addition, mineralogical data from 18,138 nonmagnetic heavy-mineral concentrate samples are included in this database. The AGDB2 includes historical geochemical data originally archived in the U.S. Geological Survey Rock Analysis Storage System (RASS) database, used from the mid-1960s through the late 1980s and the U.S. Geological Survey PLUTO database used from the mid-1970s through the mid-1990s. All of these data are currently maintained in the National Geochemical Database (NGDB). Retrievals from the NGDB were used to generate most of the AGDB data set. These data were checked for accuracy regarding sample location, sample media type, and analytical methods used. This arduous process of reviewing, verifying and, where necessary, editing all U.S. Geological Survey geochemical data resulted in a significantly improved Alaska geochemical dataset. USGS data that were not previously in the NGDB because the data predate the earliest U.S. Geological Survey geochemical databases, or were once excluded for programmatic reasons, are included here in the AGDB2 and will be added to the NGDB. The AGDB2 data provided here are the most accurate and complete to date, and should be useful for a wide variety of geochemical studies. The AGDB2 data provided in the linked database may be updated or changed periodically.

Alaska↗

USGS2025

Evaluation of the sensitivity of a federally endangered freshwater mussel (Venustaconcha trabalis) to selected chemicals

Protection of critically endangered species requires identification of factors limiting their survival and growth. Previous studies have demonstrated that unionid mussels are sensitive to some chemicals and the sensitivity was similar among different taxonomic families and tribes of mussels. However, common species of mussels were generally used in these previous studies; little is known about the sensitivity of endangered and threatened mussels relative to common species. The objective of this study was to evaluate the sensitivity of a critically endangered mussel (Tennessee bean, Venustaconcha trabalis ) to seven chemicals with different modes of toxic action (ammonia, chloride, nitrite, potassium, cobalt, manganese, nickel) in acute 96-h exposures and to three chemicals (nitrite, cobalt, iron) in chronic 28-d exposures conducted following standard methods. A commonly tested mussel (fatmucket, Lampsilis siliquoidea ) was also tested side-by-side with Tennessee bean in chronic exposures. Test chemicals were selected based on (1) chemicals of potential concern found in a review of existing data for the river where a population of Tennessee bean occurs or was historically present, (2) chemicals to which other mussels are sensitive, or (3) chemicals that had not been previously tested with mussels. Acute 50% effect concentrations (EC50s) for the seven chemicals from the Tennessee bean tests were within or close to the range of EC50s for other mussel species tested in previous studies, and chronic 20% effect concentrations for the three chemicals were similar between Tennessee bean and fatmucket, indicating the endangered species has sensitivity similar to other tested mussel species. Inclusion of the new mussel data in existing toxicity databases for freshwater organisms would rank one or more mussel species among the four most sensitive species to ammonia, chloride, potassium, and nickel in acute exposures and to nitrite, cobalt, and iron in chronic exposures.

Environmental Toxicology and Chemistry↗

USGS2022

Contrasting Common Era climate and hydrology sensitivities from paired lake sediment dinosterol hydrogen isotope records in the South Pacific Convergence Zone

Hydroclimate on ‘Uvea (Wallis et Futuna) is controlled by rainfall associated with the South Pacific Convergence Zone (SPCZ), the southern hemisphere's largest precipitation feature. To extend the short observational precipitation record, the hydrogen isotopic composition of the algal lipid biomarker dinosterol (δ 2 H dinosterol ) was measured in sediment cores from two volcanic crater lakes on ‘Uvea. The modern lakes differ morphologically and chemically but both contain freshwater within the photic zone, support phytoplankton communities inclusive of dinosterol-producing dinoflagellates, and experience identical climate conditions. δ 2 H dinosterol values track lake water isotope ratios, ultimately controlled in the tropics by precipitation amount and evaporative enrichment. However, in 88-m-deep Lac Lalolalo a steadily decreasing trend in sedimentary δ 2 H dinosterol values from −227‰ around year 988 CE to modern values as low as −303‰, suggests this lake's evolution from an active volcanic setting to the present system strongly influenced δ 2 H dinosterol values. Although current hydrology and water isotope systematics may now reflect precipitation and evaporation in this lake, the interaction between these processes and large changes in basin morphology, geochemistry, and hydrology obstruct the recovery of a climate signal from Lac Lalolalo's sedimentary δ 2 H dinosterol records. This work emphasizes the importance of site replication and the use of complementary climate reconstruction tools, especially when using molecular proxies that may be sensitive to more than one environmental parameter. Contrary to its neighbor, duplicate δ 2 H dinosterol records from 23-m-deep Lac Lanutavake varied between −277‰ and −297‰ and indicate slightly drier conditions during the time-period known as the Medieval Climate Anomaly (MCA, 950–1250 CE). The δ 2 H dinosterol signal in Lac Lanutavake was muted compared to published records from ‘Upolu (Samoa) and Efate (Vanuatu) indicating that ‘Uvea's location is not as sensitive to precipitation variability at sites farther from the SPCZ central axis. Lithogenic runoff proxies combined with δ 2 H dinosterol support the interpretation of a relatively dry MCA on ‘Uvea, ‘Upolu, and Efate, potentially due to less intense precipitation, a contracted, or a more zonally oriented SPCZ.

Efate Island, Lac Lalolalo, Lac Lanoto'o, Lac Lanu↗

USGS2011

Vulnerability of riparian ecosystems to elevated CO 2 and climate change in arid and semiarid western North America

Riparian ecosystems, already greatly altered by water management, land development, and biological invasion, are being further altered by increasing atmospheric CO 2 concentrations ([CO 2 ]) and climate change, particularly in arid and semiarid (dryland) regions. In this literature review, we (1) summarize expected changes in [CO 2 ], climate, hydrology, and water management in dryland western North America, (2) consider likely effects of those changes on riparian ecosystems, and (3) identify critical knowledge gaps. Temperatures in the region are rising and droughts are becoming more frequent and intense. Warmer temperatures in turn are altering river hydrology: advancing the timing of spring snow melt floods, altering flood magnitudes, and reducing summer and base flows. Direct effects of increased [CO 2 ] and climate change on riparian ecosystems may be similar to effects in uplands, including increased heat and water stress, altered phenology and species geographic distributions, and disrupted trophic and symbiotic interactions. Indirect effects due to climate-driven changes in streamflow, however, may exacerbate the direct effects of warming and increase the relative importance of moisture and fluvial disturbance as drivers of riparian ecosystem response to global change. Together, climate change and climate-driven changes in streamflow are likely to reduce abundance of dominant, native, early-successional tree species, favor herbaceous species and both drought-tolerant and late-successional woody species (including many introduced species), reduce habitat quality for many riparian animals, and slow litter decomposition and nutrient cycling. Climate-driven changes in human water demand and associated water management may intensify these effects. On some regulated rivers, however, reservoir releases could be managed to protect riparian ecosystem. Immediate research priorities include determining riparian species' environmental requirements and monitoring riparian ecosystems to allow rapid detection and response to undesirable ecological change.

Global Change Biology↗

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↗

USGS2002

A review of bacterial methyl halide degradation: Biochemistry, genetics and molecular ecology

Methyl halide‐degrading bacteria are a diverse group of organisms that are found in both terrestrial and marine environments. They potentially play an important role in mitigating ozone depletion resulting from methyl chloride and methyl bromide emissions. The first step in the pathway(s) of methyl halide degradation involves a methyltransferase and, recently, the presence of this pathway has been studied in a number of bacteria. This paper reviews the biochemistry and genetics of methyl halide utilization in the aerobic bacteria Methylobacterium chloromethanicum CM4 T , Hyphomicrobium chloromethanicum CM2 T , Aminobacter strain IMB‐1 and Aminobacter strain CC495. These bacteria are able to use methyl halides as a sole source of carbon and energy, are all members of the α ‐Proteobacteria and were isolated from a variety of polluted and pristine terrestrial environments. An understanding of the genetics of these bacteria identified a unique gene ( cmuA ) involved in the degradation of methyl halides, which codes for a protein (CmuA) with unique methyltransferase and corrinoid functions. This unique functional gene, cmuA , is being used to develop molecular ecology techniques to examine the diversity and distribution of methyl halide‐utilizing bacteria in the environment and hopefully to understand their role in methyl halide degradation in different environments. These techniques will also enable the detection of potentially novel methyl halide‐degrading bacteria.

Environmental Microbiology↗

USGS2013

Species of conservation concern and environmental stressors: Local regional and global effects

Species conservation has traditionally been based on individual species within the context of their requisite habitat, which is generally defined as the communities and ecosystems deemed necessary for their presence. Conservation decisions are hampered by the fact that environmental stressors that poetically threaten the persistence of species can operate at organizational levels larger than the habitat or home range of a focal species. Resource managers must therefore simultaneously consider local, regional, and/or global scale stressors for effective conservation and management of species of concern. The wide ranging effects associated with global stressors such as climate change may exceed or exacerbate the effects of local or regional stressors, they still need to understand the direct and interactive effects of global stressors and ultimately how they affect the lands they manage. Conservation of species in southern Nevada is further complication by the fact that the region includes one of the largest and fastest growing urban centers in North America. To accomplish the goal of species conservation, resource managers must identify actionable management options that mitigate the effects of local and regional stressor in the context of the effects of global stressors that are beyond their control. Species conservation is typically focused on a subset often referred to as species of conservation concern that have either demonstrated considerable decline or are naturally rare or have limited distributions. Stressors can directly and indirectly impact species in a variety of ways and through a diversity of mechanisms. Some stressors have been more intense in the past (e.g., livestock grazing) whereas other are now only emerging as new stressors (e.g., solar energy development, climate change). The primary stressors affecting southern Nevada ecosystems are listed in table 2.1 and reviewed in detail in Chapter 2. This chapter addresses Dub-goal 1.4 in the SNAP Science Research Strategy which is to sustain and enhance southern Nevada's biotic communities to preserve biodiversity wand maintain viable populations (table 1.3; Turner and others 2009). We provide numerous examples of how stressors affect the range and/or habitat of select species of conservation concern. It is important to note that the species or groups discussed in this chapter by no means represent a comprehensive treatment of all species of conservation concern listed in Table 1.2 (Chapter 1). Rather, several species were chosen as examples for each southern Nevada ecosystem type to illustrate how stressors and linkages among them can affect species of conservation concern, keeping in mind that many of the species considered here are found in more than one ecosystem type. In addition, the stressors that may impact a species in one ecosystem may not be those that affect it in another ecosystem and different species in the same ecosystem may not be affected by the same suite of stressors. Finally, at the start of each ecosystem section we summarize key resource concerns, species used as examples, key stressors, and potential synergistic effects of those stressors relative to the species example.

Nevada↗

USGS2012

Statistical analyses to support guidelines for marine avian sampling. Final report

Interest in development of offshore renewable energy facilities has led to a need for high-quality, statistically robust information on marine wildlife distributions. A practical approach is described to estimate the amount of sampling effort required to have sufficient statistical power to identify species-specific “hotspots” and “coldspots” of marine bird abundance and occurrence in an offshore environment divided into discrete spatial units (e.g., lease blocks), where “hotspots” and “coldspots” are defined relative to a reference (e.g., regional) mean abundance and/or occurrence probability for each species of interest. For example, a location with average abundance or occurrence that is three times larger the mean (3x effect size) could be defined as a “hotspot,” and a location that is three times smaller than the mean (1/3x effect size) as a “coldspot.” The choice of the effect size used to define hot and coldspots will generally depend on a combination of ecological and regulatory considerations. A method is also developed for testing the statistical significance of possible hotspots and coldspots. Both methods are illustrated with historical seabird survey data from the USGS Avian Compendium Database. Our approach consists of five main components: 1. A review of the primary scientific literature on statistical modeling of animal group size and avian count data to develop a candidate set of statistical distributions that have been used or may be useful to model seabird counts. 2. Statistical power curves for one-sample, one-tailed Monte Carlo significance tests of differences of observed small-sample means from a specified reference distribution. These curves show the power to detect "hotspots" or "coldspots" of occurrence and abundance at a range of effect sizes, given assumptions which we discuss. 3. A model selection procedure, based on maximum likelihood fits of models in the candidate set, to determine an appropriate statistical distribution to describe counts of a given species in a particular region and season. 4. Using a large database of historical at-sea seabird survey data, we applied this technique to identify appropriate statistical distributions for modeling a variety of species, allowing the distribution to vary by season. For each species and season, we used the selected distribution to calculate and map retrospective statistical power to detect hotspots and coldspots, and map pvalues from Monte Carlo significance tests of hotspots and coldspots, in discrete lease blocks designated by the U.S. Department of Interior, Bureau of Ocean Energy Management (BOEM). 5. Because our definition of hotspots and coldspots does not explicitly include variability over time, we examine the relationship between the temporal scale of sampling and the proportion of variance captured in time series of key environmental correlates of marine bird abundance, as well as available marine bird abundance time series, and use these analyses to develop recommendations for the temporal distribution of sampling to adequately represent both shortterm and long-term variability. We conclude by presenting a schematic “decision tree” showing how this power analysis approach would fit in a general framework for avian survey design, and discuss implications of model assumptions and results. We discuss avenues for future development of this work, and recommendations for practical implementation in the context of siting and wildlife assessment for offshore renewable energy development projects.

NOAA Technical Memorandum↗

USGS2014

Predictive Management of Asian Carps in the Upper Mississippi River System

Prolific non-native organisms pose serious threats to ecosystems and economies worldwide. Nonnative bighead carp ( Hypophthalmichthys nobilis ) and silver carp ( H. molitrix ), collectively referred to as Asian carps, continue to colonize aquatic ecosystems throughout the central United States. These species are r-selected, exhibiting iteroparous spawning, rapid growth, broad environmental tolerance, high density, and long-distance movement. Hydrological, thermal, and physicochemical conditions are favorable for establishment beyond the current range, rendering containment and control imperative. Ecological approaches to confine Asian carp populations and prevent colonization characterize contemporary management in the United States. Foraging and reproduction of Asian carps govern habitat selection and movement, providing valuable insight for predictive control. Current management approaches are progressive and often anticipatory but deficient in human dimensions. We define predictive management of Asian carps as synthesis of ecology and human dimensions at regional and local scales to develop strategies for containment and control. We illustrate predictive management in the Upper Mississippi River System and suggest resource managers integrate predictive models, containment paradigms, and human dimensions to design effective, socially acceptable management strategies. Through continued research, university-agency collaboration, and public engagement, predictive management of Asian carps is an auspicious paradigm for preventing and alleviating consequences of colonization in the United States.

Reviews in Fisheries Science & Aquaculture↗