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USGS2011

Proceedings of a Coastal and Marine Spatial Planning Workshop for the Western United States

Recent scientific and ocean policy assessments demonstrate that a fundamental change in our current management system is required to achieve the long-term health of our ocean, coasts, and Great Lakes in order to sustain the services and benefits they provide to society. The present (2011) species- and sector-centric way we manage these ecosystems cannot account properly for cumulative effects, sustaining multiple ecosystem services, and holistically and explicitly evaluating the tradeoffs associated with proposed alternative and multiple human uses. A transition to an ecosystem-based approach to management and conservation of coastal and marine resources is needed. Competing uses and activities such as commerce, recreation, cultural practices, energy development, conservation, and national security are increasing pressure for new and expanded resource usage in coastal marine ecosystems. Current management efforts use a sector-by-sector approach that mostly focuses on a limited range of tools and outcomes [for example, oil and gas leases, fishery management plans, and Marine Protected Areas (MPAs)]. A comprehensive, ecosystem-based, and proactive approach to planning and managing these uses and activities is needed. Further, scientific understanding and information are essential to achieve an integrated decision-making process that includes knowledge of ecosystem services, existing and possible future conditions, and potential consequences of natural and anthropogenic events. Because no single government agency has executive authority for coastal or ocean resources, conflicting objectives around competing uses abound. In recent years, regional- and state-level initiatives in Coastal and Marine Spatial Planning (CMSP) have emerged to coordinate management activities. In some respects, the components and steps of the overall CMSP process are similar to how existing ocean resources are regulated and managed. For example, the Bureau of Ocean Energy Management Regulation and Enforcement (BOEMRE) uses spatial planning exercises in State Renewable Energy Task Force meetings to identify competing and conflicting ocean uses, and to delineate areas suitable for renewable energy development. Similarly terrestrial areas such as in national parks and national wildlife refuges managed by the Department of the Interior (DOI) prepare management plans for preservation and restoration of species and habitats of concern, some of which are protected by law. The analogy to CMSP is clear - multiple users and multiple expectations, resulting in the requirement to establish spatial plans for management of different resources and different ecosystem services. A two-day workshop on December 1-2, 2010, was convened for DOI representatives and several key non-DOI participants with roles in CMSP as a step toward clarifying national perspectives and consequences of the National Ocean Policy for the West (appendix 1). Discussions helped to develop an understanding of CMSP from the federal perspective and to identify regional priorities. An overarching theme was to promote a better understanding of current and future science needs. The workshop format included briefings by key Federal agencies on their understanding of the national focus followed by discussion of regional issues, including the needs for scientific information and coordination. The workshop also explored potential science contributions by Federal agencies and others; utilizing current capabilities, data, and information systems; and provided a foundation for possible future regional workshops focusing in turn on the West Coast Region (California, Oregon, and Washington), Pacific Islands (sometimes referred to as Oceania) and Alaska. Participants were asked to share information in the following areas, recognizing that the purpose would be to learn more about the national perspective (see appendixes 2-4): Explore how the Western U.S. (Alaska, Pacific Islands, and West Coast Region) migh

Open-File Report↗

USGS2000

Atmospheric nitrogen in the Mississippi River Basin: Amissions, deposition and transport

Atmospheric deposition of nitrogen has been cited as a major factor in the nitrogen saturation of forests in the north-eastern United States and as a contributor to the eutrophication of coastal waters, including the Gulf of Mexico near the mouth of the Mississippi River. Sources of nitrogen emissions and the resulting spatial patterns of nitrogen deposition within the Mississippi River Basin, however, have not been fully documented. An assessment of atmospheric nitrogen in the Mississippi River Basin was therefore conducted in 1998-1999 to: (1) evaluate the forms in which nitrogen is deposited from the atmosphere; (2) quantify the spatial distribution of atmospheric nitrogen deposition throughout the basin; and (3) relate locations of emission sources to spatial deposition patterns to evaluate atmospheric transport. Deposition data collected through the NADP/NTN (National Atmospheric Deposition Program/National Trends Network) and CASTNet (Clean Air Status and Trends Network) were used for this analysis. NO(x) Tier 1 emission data by county was obtained for 1992 from the US Environmental Protection Agency (Emissions Trends Viewer CD, 1985-1995, version 1.0, September 1996) and NH3 emissions data was derived from the 1992 Census of Agriculture (US Department of Commerce. Census of Agriculture, US Summary and County Level Data, US Department of Commerce, Bureau of the Census. Geographic Area series, 1995:1b) or the National Agricultural Statistics Service (US Department of Agriculture. National Agricultural Statistics Service Historical Data. Accessed 7/98 at URL, 1998. http://www.usda.gov/nass/pubs/hisdata.htm). The highest rates of wet deposition of NO3- were in the north-eastern part of the basin, downwind of electric utility plants and urban areas, whereas the highest rates of wet deposition of NH4+ were in Iowa, near the center of intensive agricultural activities in the Midwest. The lowest rates of atmospheric nitrogen deposition were on the western (windward) side of the basin, which suggests that most of the nitrogen deposited within the basin is derived from internal sources. Atmospheric transport eastward across the basin boundary is greater for NO3- than NH4+, but a significant amount of NH4+ is likely to be transported out of the basin through the formation of (NH4)2SO4 and NH4NO3 particles - a process that greatly increases the atmospheric residence time of NH4+. This process is also a likely factor in the atmospheric transport of nitrogen from the Midwest to upland forest regions in the North-East, such as the western Adirondack region of New York, where NH4+ constitutes 38% of the total wet deposition of N.

Science of Total Environment↗

USGS2021

Carbonate-hosted microbial communities are prolific and pervasive methane oxidizers at geologically diverse marine methane seep sites

At marine methane seeps, vast quantities of methane move through the shallow subseafloor, where it is largely consumed by microbial communities. This process plays an important role in global methane dynamics, but we have yet to identify all of the methane sinks in the deep sea. Here, we conducted a continental-scale survey of seven geologically diverse seafloor seeps and found that carbonate rocks from all sites host methane-oxidizing microbial communities with substantial methanotrophic potential. In laboratory-based mesocosm incubations, chimney-like carbonates from the newly described Point Dume seep off the coast of Southern California exhibited the highest rates of anaerobic methane oxidation measured to date. After a thorough analysis of physicochemical, electrical, and biological factors, we attribute this substantial metabolic activity largely to higher cell density, mineral composition, kinetic parameters including an elevated V max , and the presence of specific microbial lineages. Our data also suggest that other features, such as electrical conductance, rock particle size, and microbial community alpha diversity, may influence a sample’s methanotrophic potential, but these factors did not demonstrate clear patterns with respect to methane oxidation rates. Based on the apparent pervasiveness within seep carbonates of microbial communities capable of performing anaerobic oxidation of methane, as well as the frequent occurrence of carbonates at seeps, we suggest that rock-hosted methanotrophy may be an important contributor to marine methane consumption.

Proceedings of the National Academy of Sciences (P↗

USGS2020

Evaluation of EPT macroinvertebrate metrics in small streams located within the non-connected stormwater management region of Kansas City, Missouri, USA

During 2012-2014, we evaluated macroinvertebrate communities in streams draining the non-connected stormwater management region (Municipal Separate Storm Sewer System, or MS4) within the Kansas City metropolitan area utilizing the Missouri bioassessment protocols. Trends in aquatic life impairment status based on Missouri's Macroinvertebrate Stream Condition Index (MSCI), as well as richness and abundance of EPT indicator metrics (Ephemeroptera, Plecoptera, Trichoptera), were compared between rural control sites and both transitional and urban stream sites representing varying stages of land use conversion. As compared to non-urban control sites, EPT taxa richness was significantly lower at MS4 urban sites during all three years (p = 0.007 – 0.013) and MS4 transitional sites during one of three years (p=0.48). EPT abundance (%) was significantly lower at MS4 urban sites during all years (p = 0.008 – 0.013) and MS4 transitional sites during one of three years (p=0.34). Mean EPT abundances ranged between 0.6% - 10.3% at urban MS4 sites, and always exceeded 18% at control sites. Both EPT richness and abundance were lower at the MS4 control site but means for EPT and other core metrics at this site were most often similar to non-urban control sites based on analysis of variance (ANOVA). MS4 transitional sites with active development in their watersheds were partially-supporting in their impairment status, and EPT metrics had lower means and generally more variability than control sites. Temporal trends indicate non-urban control and MS4 control sites consistently meet fully-supporting impairment status based on overall MSCI scores, but no study sites currently meet regional expectations (as defined by state reference streams) for either of the EPT metrics. Results indicate that Missouri and Kansas biocriteria for both EPT metrics are not consistently being met at any stream sites in the Kansas City metro area, including fully-supporting control sites and MS4 streams that receive stormwater runoff in watersheds with urban development that is well-established or currently transitioning to urban or suburban land uses.

Missouri↗

USGS2001

Anomalously high b-values in the South Flank of Kilauea volcano, Hawaii: Evidence for the distribution of magma below Kilauea's East rift zone

The pattern of b-value of the frequency-magnitude relation, or mean magnitude, varies little in the Kaoiki-Hilea area of Hawaii, and the b-values are normal, with b = 0.8 in the top 10 km and somewhat lower values below that depth. We interpret the Kaoiki-Hilea area as relatively stable, normal Hawaiian crust. In contrast, the b-values beneath Kilauea's South Flank are anomalously high (b = 1.3-1.7) at depths between 4 and 8 km, with the highest values near the East Rift zone, but extending 5-8 km away from the rift. Also, the anomalously high b-values vary along strike, parallel to the rift zone. The highest b-values are observed near Hiiaka and Pauahi craters at the bend in the rift, the next highest are near Makaopuhi and also near Puu Kaliu. The mildest anomalies occur adjacent to the central section of the rift. The locations of the three major and two minor b-value anomalies correspond to places where shallow magma reservoirs have been proposed based on analyses of seismicity, geodetic data and differentiated lava chemistry. The existence of the magma reservoirs is also supported by magnetic anomalies, which may be areas of dike concentration, and self-potential anomalies, which are areas of thermal upwelling above a hot source. The simplest explanation of these anomalously high b-values is that they are due to the presence of active magma bodies beneath the East Rift zone at depths down to 8 km. In other volcanoes, anomalously high b-values correlate with volumes adjacent to active magma chambers. This supports a model of a magma body beneath the East Rift zone, which may widen and thin along strike, and which may reach 8 km depth and extend from Kilauea's summit to a distance of at least 40 km down rift. The anomalously high b-values at the center of the South Flank, several kilometers away from the rift, may be explained by unusually high pore pressure throughout the South Flank, or by anomalously strong heterogeneity due to extensive cracking, or by both phenomena. The major b-value anomalies are located SSE of their parent reservoirs, in the direction of motion of the flank, suggesting that magma reservoirs leave an imprint in the mobile flank. We hypothesize that the extensive cracking may have been acquired when the anomalous parts of the South Flank, now several kilometers distant from the rift zone, were generated at the rift zone near persistent reservoirs. Since their generation, these volumes may have moved seaward, away from the rift, but earthquakes occurring in them still use the preexisting complex crack distribution. Along the decollement plane at 10 km depth, the b-values are exceptionally low (b = 0.5), suggesting faulting in a more homogeneous medium. ?? 2001 Elsevier Science B.V. All rights reserved.

Journal of Volcanology and Geothermal Research↗

USGS2026

Millennial-scale climatic and cultural impacts on vegetation and fire at the southern edge of the Rocky Mountains, USA

Mountain forests and woodlands in semiarid regions of the world are threatened by climatic change and other human impacts. In the southwestern USA, climate and culturally driven changes to the structure and fire regimes of dry coniferous forests over recent centuries are well documented by tree-ring archives. However, the roles of climate and people as drivers of millennial-scale changes are less understood. We present a new record of vegetation dynamics and regional fire activity inferred from pollen, microscopic charcoal, and sediment geochemistry from Santa Fe Lake, NM (3532 m a.s.l.), the southernmost natural lake in the Rocky Mountains. Declining elemental intensities (e.g., Ti, Fe, Si) record local deglaciation after 14,000 cal yr BP followed by upslope expansion of trees indicated by increasing Pinus and Picea pollen percentages as the climate warmed during the Late Glacial. Cool, dry growing seasons probably limited the establishment of dense forests until after 12,200 cal yr BP when we hypothesize that Pinus ponderosa (ponderosa pine) expanded regionally (i.e., within 10–100 km) due to continued warming and a possible increase in monsoonal precipitation. Subalpine forests established near Santa Fe Lake by 10,300 cal yr BP as indicated by abundant conifer stomates and increasing Picea and Pinus aristata pollen percentages, which are highest after 5100 cal yr BP. Increasing Juniperus -type, Quercus , and Pinus edulis -type pollen record changes in vegetation belts at lower elevations after 10,300 cal yr BP. Maize pollen, an unambiguous indicator of Puebloan agriculture, first appears at 800 cal yr BP (1150 cal yr CE) and is present through 1600 cal yr CE when Spanish colonization brought cultural upheaval and population loss to local indigenous communities. Regional fire activity, inferred from microscopic charcoal influx, remained relatively constant for most of our record. However, average microscopic charcoal influx more than doubled relative to the rest of the Holocene during the last 2000 years, with the highest influx after 1550 cal yr BP (400 cal yr CE). The increased influx of microscopic charcoal coincides with archaeological evidence for dramatic regional population growth in the northern Rio Grande region and probably reflects extensive cultural burning associated with the development of an agricultural economy. Although climate was an important driver of vegetation change and fire regimes in the mountains of the southwestern USA during the Holocene, our results suggest that human impacts on regional burning during the last 2000 years far exceeded earlier climate-driven variation.

Rocky Mountains↗

USGS2024

Trends in colony sizes for five colonial waterbird species in the Atlantic Flyway

Robust estimates of colonial waterbird (CWB) breeding population trends are deficient owing to a lack of range wide, standardized survey efforts. Evaluating conservation priorities and effectiveness of management requires reliable trend estimates across multiple spatial scales. One potential data source for CWB trend estimation is the Colonial Waterbird Database, created in 2003 by U.S. Geological Survey and the U.S. Fish and Wildlife Service and intermittently updated since then. The database combines state or provincial survey data, particularly from the United States Atlantic Flyway, with historical colony counts obtained from publications. We combined recently collected survey data from Atlantic Flyway states and provinces with data archived in the database to generate population size trend estimates for five species: Double-crested Cormorant ( Phalacrocorax auritus ), Laughing Gull ( Leucophaeus atricilla ), Least Tern ( Sternula antillarum ), Common Tern ( Sterna hirundo ), and Black Skimmer ( Rynchops niger ). These species represent two actively managed conflict species and three species of conservation concern, respectively. We used mixed effects models to fit an exponential growth model to determine yearly trends in populations at Atlantic Flyway- and state-scales with survey data collected between 1964 and 2019. Direction of within-state trend estimates varied. Trends for some species (Common Tern, Laughing Gull) were increasing in northern states and decreasing further south. At the Flyway scale, Double-crested Cormorant increased (2.08 ± 0.28 % year-1) and Least Tern (-1.40 ± 0.36 % year-1) and Black Skimmer (-1.13 ± 0.68 % year -1) decreased, while Flyway-scale trends in Common Tern and Laughing Gull were not significant. Our analysis provides cross-state trend estimates to inform CWB management actions along the Atlantic Flyway.

Cooperator Science Series↗

USGS2005

A regional classification scheme for estimating reference water quality in streams using land-use-adjusted spatial regression-tree analysis

Various approaches are used to subdivide large areas into regions containing streams that have similar reference or background water quality and that respond similarly to different factors. For many applications, such as establishing reference conditions, it is preferable to use physical characteristics that are not affected by human activities to delineate these regions. However, most approaches, such as ecoregion classifications, rely on land use to delineate regions or have difficulties compensating for the effects of land use. Land use not only directly affects water quality, but it is often correlated with the factors used to define the regions. In this article, we describe modifications to SPARTA (spatial regression-tree analysis), a relatively new approach applied to water-quality and environmental characteristic data to delineate zones with similar factors affecting water quality. In this modified approach, land-use-adjusted (residualized) water quality and environmental characteristics are computed for each site. Regression-tree analysis is applied to the residualized data to determine the most statistically important environmental characteristics describing the distribution of a specific water-quality constituent. Geographic information for small basins throughout the study area is then used to subdivide the area into relatively homogeneous environmental water-quality zones. For each zone, commonly used approaches are subsequently used to define its reference water quality and how its water quality responds to changes in land use. SPARTA is used to delineate zones of similar reference concentrations of total phosphorus and suspended sediment throughout the upper Midwestern part of the United States. ?? 2006 Springer Science+Business Media, Inc.

Environmental Management↗

USGS1995

Water-quality assessment of the upper Snake River Basin, Idaho and western Wyoming — Summary of aquatic biological data for surface water through 1992

The 35,800-square-mile upper Snake River Basin in eastern Idaho and western Wyoming was one of 20 areas selected for water-quality study under the National Water-Quality Assessment Program. As part of the initial phase of the study, data were compiled to describe the current (1992) and historical aquatic biological conditions of surface water in the basin. This description of natural and human environmental factors that affect aquatic life provides the framework for evaluating the status and trends of aquatic biological conditions in streams of the basins. Water resource development and stream alterations, irrigated agriculture, grazing, aquaculture, and species introductions have affected stream biota in the upper Snake River Basin. Cumulative effects of these activities have greatly altered cold-water habitat and aquatic life in the middle Snake River reach (Milner Dam to King Hill). Most of the aquatic Species of Special Concern in the basin , consisting of eight native mollusks and three native fish species, are in this reach of the Snake River. Selected long-term studies, including comprehensive monitoring on Rock Creek, have shown reduced pollutant loadings as a result of implementing practice on cropland; however, aquatic life remains affected by agricultural land use. Community level biological data are lacking for most of the streams in the basin, especially for large river. Aquatic life used to assess water quality of the basin includes primarily macroinvertebrate and fish communities. At least 26 different macroinvertebrate and fish community metrics have been utilized to assess water quality of the basin. Eight species of macroinvertebrates and fish are recognized as Species of Special Concern. The native fish faunas of the basin are composed primarily of cold-water species representing 5 families and 26 species. An additional 13 fish species have been introduced to the basin. Concentrations of synthetic organic compounds and trace-element contaminants in whole fish collected in the basin during 1970-90 generally did not exceed National Academy of Sciences and National Academy of Engineering concentration guidelines or the 1980-81 geometric mean concentrations from samples collected as part of the U.S. Fish and Wildlife Service National Contaminant Biomonitoring Program. Currently, there are no State fish consumption advisories on any streams in the basin, The organochlorine compounds DDT and PCB's were the most frequently detected fish tissue contaminant. Selected long-term data on DDT, its metabolites, and PCB's indicate decreasing concentrations of these compounds. Arsenic, mercury, and selenium were slightly elevated compared with nationwide baseline concentrations and may indicate bioaccumularion in the food chain. Concentrations of most other trace elements in fish tissue were below levels of concerns for the protection of humans and wildlife.

Idaho, Wyoming↗

USGS2013

Intra-population variation in activity ranges, diel patterns, movement rates, and habitat use of American alligators in a subtropical estuary

Movement and habitat use patterns are fundamental components of the behaviors of mobile animals and help determine the scale and types of interactions they have with their environments. These behaviors are especially important to quantify for top predators because they can have strong effects on lower trophic levels as well as the wider ecosystem. Many studies of top predator movement and habitat use focus on general population level trends, which may overlook important intra-population variation in behaviors that now appear to be common. In an effort to better understand the prevalence of intrapopulation variation in top predator movement behaviors and the potential effects of such variation on ecosystem dynamics, we examined the movement and habitat use patterns of a population of adult American alligators ( Alligator mississippiensis ) in a subtropical estuary for nearly four years. We found that alligators exhibited divergent behaviors with respect to activity ranges, movement rates, and habitat use, and that individualized behaviors were stable over multiple years. We also found that the variations across the three behavioral metrics were correlated such that consistent behavioral types emerged, specifically more exploratory individuals and more sedentary individuals. Our study demonstrates that top predator populations can be characterized by high degrees of intra-population variation in terms of movement and habitat use behaviors that could lead to individuals filling different ecological roles in the same ecosystem. By extension, one-size-fits-all ecosystem and species-specific conservation and management strategies that do not account for potential intra-population variation in top predator behaviors may not produce the desired outcomes in all cases.

Estuarine, Coastal and Shelf Science↗

USGS2009

GRS evidence and the possibility of paleooceans on Mars

The Gamma Ray Spectrometer (Mars Odyssey spacecraft) has revealed elemental distributions of potassium (K), thorium (Th), and iron (Fe) on Mars that require fractionation of K (and possibly Th and Fe) consistent with aqueous activity. This includes weathering, evolution of soils, and transport, sorting, and deposition, as well as with the location of first-order geomorphological demarcations identified as possible paleoocean boundaries. The element abundances occur in patterns consistent with weathering in situ and possible presence of relict or exhumed paleosols, deposition of weathered materials (salts and clastic minerals), and weathering/transport under neutral to acidic brines. The abundances are explained by hydrogeology consistent with the possibly overlapping alternatives of paleooceans and/or heterogeneous rock compositions from diverse provenances (e.g., differing igneous compositions). ?? 2008 Elsevier Ltd.

Planetary and Space Science↗

USGS2011

Deep scientific drilling in the San Andreas Fault Zone

A deep scientific drilling experiment in San Andreas fault zone would provide data essential to understanding the structure, composition, mechanical behavior, and physical state of an active, major plate-boundary fault. Toward this end, we are working with an international team of scientists and engineers to propose a long-term, integrated program of surface-based geological and geophysical investigations and deep drilling along the San Andreas fault system. Prior to drilling, a suite of comparative geodynamic models will be developed incorporating detailed investigations of geology, crustal structure, geophysical environment, hydrology, seismotectonics, and fault-movement history at each of the candidate sites. These studies will have a major impact on our understanding of the structure and physical properties of the San Andreas fault system and will form a critical framework for applying the knowledge gained in a deep San Andreas borehole to other segments of the fault and other tectonic environments.

California, Nevada↗

USGS2007

Electrical activity during the 2006 Mount St. Augustine volcanic eruptions

By using a combination of radio frequency time-of-arrival and interferometer measurements, we observed a sequence of lightning and electrical activity during one of Mount St. Augustine's eruptions. The observations indicate that the electrical activity had two modes or phases. First, there was an explosive phase in which the ejecta from the explosion appeared to be highly charged upon exiting the volcano, resulting in numerous apparently disorganized discharges and some simple lightning. The net charge exiting the volcano appears to have been positive. The second phase, which followed the most energetic explosion, produced conventional-type discharges that occurred within plume. Although the plume cloud was undoubtedly charged as a result of the explosion itself, the fact that the lightning onset was delayed and continued after and well downwind of the eruption indicates that in situ charging of some kind was occurring, presumably similar in some respects to that which occurs in normal thunderstorms.

Alaska↗

USGS2016

The Water-Quality Partnership for National Parks—U.S. Geological Survey and National Park Service, 1998–2016

The U.S. Geological Survey (USGS) and the National Park Service (NPS) work together through the USGS–NPS Water-Quality Partnership to support a broad range of policy and management needs related to high-priority water-quality issues in national parks. The program was initiated in 1998 as part of the Clean Water Action Plan, a Presidential initiative to commemorate the 25th anniversary of the Clean Water Act. Partnership projects are developed jointly by the USGS and the NPS. Studies are conducted by the USGS and findings are used by the NPS to guide policy and management actions aimed at protecting and improving water quality. The National Park Service manages many of our Nation’s most highly valued aquatic systems across the country, including portions of the Great Lakes, ocean and coastal zones, historic canals, reservoirs, large rivers, high-elevation lakes and streams, geysers, springs, and wetlands. So far, the Water-Quality Partnership has undertaken 217 projects in 119 national parks. In each project, USGS studies and assessments ( http://water.usgs.gov/nps_partnership/pubs.php ) have supported science-based management by the NPS to protect and improve water quality in parks. Some of the current projects are highlighted in the NPS Call to Action Centennial initiative, Crystal Clear, which celebrates national park water-resource efforts to ensure clean water for the next century of park management ( http://www.nature.nps.gov/water/crystalclear/ ). New projects are proposed each year by USGS scientists working in collaboration with NPS staff in specific parks. Project selection is highly competitive, with an average of only eight new projects funded each year out of approximately 75 proposals that are submitted. Since the beginning of the Partnership in 1998, 189 publications detailing project findings have been completed. The 217 studies have been conducted in 119 NPS-administered lands, extending from Denali National Park and Preserve in Alaska to Everglades National Park in Florida, and from Acadia National Park in the Northeast to park lands in Hawaii and Pacific Island territories in the West. Project goals range from periodic stream monitoring, to determining the occurrence and concentrations of contaminants and the potential for them to exceed human health or aquatic life criteria, to conducting interpretive studies to evaluate the effect(s) on or vulnerability of national park resources to visitor usage and other natural and anthropogenic activities.

Fact Sheet↗

USGS2000

Consequences of slow growth for 230Th/U dating of Quaternary opals, Yucca Mountain, NV, USA

Thermal ionization mass-spectrometry 234U/238U and 230Th/238U data are reported for uranium-rich opals coating fractures and cavities within the silicic tuffs forming Yucca Mountain, NV, the potential site of a high-level radioactive waste repository. High uranium concentrations (up to 207 ppm) and extremely high 230Th/232Th activity ratios (up to about 106) make microsamples of these opals suitable for precise 230Th/U dating. Conventional 230Th/U ages range from 40 to greater than 600 ka, and initial 234U/238U activity ratios between 1.03 and 8.2. Isotopic evidence indicates that the opals have not experienced uranium mobility; however, wide variations in apparent ages and initial 234U/238U ratios for separate subsamples of the same outermost mineral surfaces, positive correlation between ages and sample weights, and negative correlation between 230Th/U ages and calculated initial 234U/238U are inconsistent with the assumption that all minerals in a given subsample was deposited instantaneously. The data are more consistent with a conceptual model of continuous deposition where secondary mineral growth has occurred at a constant, slow rate up to the present. This model assumes that individual subsamples represent mixtures of older and younger material, and that calculations using the resulting isotope ratios reflect an average age. Ages calculated using the continuous-deposition model for opals imply average mineral growth rates of less than 5 mm/m.y. The model of continuous deposition also predicts discordance between ages obtained using different radiometric methods for the same subsample. Differences in half-lives will result in younger apparent ages for the shorter-lived isotope due to the greater influence of younger materials continuously added to mineral surfaces. Discordant 14C, 230Th/U and U-Pb ages obtained from outermost mineral surfaces at Yucca Mountain support this model. (C) 2000 Elsevier Science B.V. All rights reserved.

Chemical Geology↗

USGS2018

“Naturalness” in designated Wilderness: Long-term changes in non-native plant dynamics on campsites, Boundary Waters, Minnesota

Wilderness areas in the United States are preserved for their untrammeled naturalness and opportunities for unconfined recreation. The Boundary Waters Canoe Area Wilderness has these qualities, but long-term recreation visitation pressures on campsites can cause significant ecological changes. This article explores changes on campsites, specifically examining non-native plant ecology over 3 decades. The research replicates a 1982 study analyzing vegetation composition and cover on campsites and environmentally paired controls. Camping activities have removed substantial tree cover on campsites, altering their ecological conditions and perceived wilderness character. Over the span of 32 years, the number of non-native plant species found on campsites has not risen, although their mean relative cover has increased significantly and they have spread to more sites. Of the 23 non-native herbs and grasses found on the campsites, only Cirsium arvense is considered a noxious weed by the state of Minnesota. Other noninvasive, non-native plants fall into a gray area in the context of "naturalness" for an area protected as Wilderness because they provide some positive ecological services even as they degrade wilderness character. Thus, wilderness managers face a difficult challenge in coping with the long-term impacts of visitor use on wilderness conditions and character.

Minnesota↗

USGS2017

Use of fish telemetry in rehabilitation planning, management, and monitoring in Areas of Concern in the Laurentian Great Lakes

Freshwater ecosystems provide many ecosystem services; however, they are often degraded as a result of human activity. To address ecosystem degradation in the Laurentian Great Lakes, Canada and the United States of America established the Great Lakes Water Quality Agreement (GLWQA). In 1987, 43 highly polluted and impacted areas were identified under the GLWQA as having one or more of 14 Beneficial Use Impairments (BUIs) to the physical and chemical habitat for fish, wildlife and humans, and were designated as Areas of Concern (AOC). Subnational jurisdictions combined with local stakeholders, with support from federal governments, developed plans to remediate and restore these sites. Biotelemetry (the tracking of animals using electronic tags) provides information on the spatial ecology of fish in the wild relevant to habitat management and stock assessment. Here, seven case studies are presented where biotelemetry data were directly incorporated within the AOC Remedial Action Plan (RAP) process. Specific applications include determining seasonal fish–habitat associations to inform habitat restoration plans, identifying the distribution of pollutant-indicator species to identify exposure risk to contamination sources, informing the development of fish passage facilities to enable fish to access fragmented upstream habitats, and assessing fish use of created or restored habitats. With growing capacity for fish biotelemetry research in the Great Lakes, we discuss the strengths and weaknesses of incorporating biotelemetry into AOC RAP processes to improve the science and practice of restoration and to facilitate the delisting of AOCs.

Great Lakes↗

USGS2018

Science support for evaluating natural recovery of polychlorinated biphenyl concentrations in fish from Crab Orchard Lake, Crab Orchard National Wildlife Refuge, Illinois

Introduction Crab Orchard Lake in southern Illinois is one of the largest and most popular recreational lakes in the state. Construction of the nearly 7,000-acre reservoir in the late 1930s created employment opportunities through the Works Progress Administration, and the lake itself was intended to supply water, control flooding, and provide recreational opportunities for local communities (Stall, 1954). In 1942, the Department of War appropriated or purchased more than 20,000 acres of land around Crab Orchard Lake and constructed the Illinois Ordnance Plant, which manufactured bombs and anti-tank mines during World War II. After the war, an Act of Congress transferred the property to the U.S. Department of the Interior. Crab Orchard National Wildlife Refuge was established on August 5, 1947, for the joint purposes of wildlife conservation, agriculture, recreation, and industry. Production of explosives continued, but new industries also moved onsite. More than 200 tenants have held leases with Crab Orchard National Wildlife Refuge and have operated a variety of manufacturing plants (electrical components, plated metal parts, ink, machined parts, painted products, and boats) on-site. Soils, water, and sediments in several areas of the refuge were contaminated with hazardous substances from handling and disposal methods that are no longer acceptable environmental practice (for example, direct discharge to surface water, use of unlined landfills). Polychlorinated biphenyl (PCB) contamination at the refuge was identified in the 1970s, and a PCB-based fish-consumption advisory has been in effect since 1988 for Crab Orchard Lake. The present advisory covers common carp ( Cyprinus carpio ) and channel catfish ( Ictalurus punctatus ); see Illinois Department of Public Health (2017). Some of the most contaminated areas of the refuge were actively remediated, and natural ecosystem recovery processes are expected to further reduce residual PCB concentrations in the lake. The U.S. Fish and Wildlife Service sought technical support to understand environmental drivers of current (2017) PCB residues in fish tissue and patterns in PCB residues through time to inform the fish-consumption advisory for Crab Orchard Lake. This project is planned in two phases (Tasks 1 and 2); the first phase is included in this report. Task 1, reported here, includes a review of existing literature and a brief overview focused on environmental and biochemical/physiological processes that drive PCB residues in fish tissue. This review specifically targets processes that are relevant for freshwater lacustrine environments such as those at Crab Orchard Lake. In addition to discussions of environmental fate, metabolism, and accumulation of PCBs, this review includes a brief scientifically based explanation of approaches used to establish fish-consumption advisories. A planned second task (Task 2) will include a compilation and summary of existing data on PCB residues in fish tissue samples from Crab Orchard Lake. This summary will also place Crab Orchard Lake data in a broader geographic context through a comparison with fish data from other Midwestern lakes. When Task 1 and Task 2 are complete, resource managers will have (a) a synthesis of existing literature that characterizes the processes influencing the fate of residual PCBs remaining in systems such as Crab Orchard Lake, (b) a summary of natural PCB attenuation processes for use in risk communication with the public, and (c) a summary of existing data on PCBs in fish tissues from Crab Orchard Lake, including exploratory plots of tissue residues through time. Overall, this project will provide data to help resource managers better understand the ecological and public health consequences of residual PCBs in Crab Orchard Lake.

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