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At least 1,315 records · Page 73Linked to original sources
USGS2007

Microbial sulfate reduction and metal attenuation in pH 4 acid mine water

Sediments recovered from the flooded mine workings of the Penn Mine, a Cu-Zn mine abandoned since the early 1960s, were cultured for anaerobic bacteria over a range of pH (4.0 to 7.5). The molecular biology of sediments and cultures was studied to determine whether sulfate-reducing bacteria (SRB) were active in moderately acidic conditions present in the underground mine workings. Here we document multiple, independent analyses and show evidence that sulfate reduction and associated metal attenuation are occurring in the pH-4 mine environment. Water-chemistry analyses of the mine water reveal: (1) preferential complexation and precipitation by H2S of Cu and Cd, relative to Zn; (2) stable isotope ratios of 34S/32S and 18O/16O in dissolved SO4 that are 2-3 ??? heavier in the mine water, relative to those in surface waters; (3) reduction/oxidation conditions and dissolved gas concentrations consistent with conditions to support anaerobic processes such as sulfate reduction. Scanning electron microscope (SEM) analyses of sediment show 1.5-micrometer, spherical ZnS precipitates. Phospholipid fatty acid (PLFA) and denaturing gradient gel electrophoresis (DGGE) analyses of Penn Mine sediment show a high biomass level with a moderately diverse community structure composed primarily of iron- and sulfate-reducing bacteria. Cultures of sediment from the mine produced dissolved sulfide at pH values near 7 and near 4, forming precipitates of either iron sulfide or elemental sulfur. DGGE coupled with sequence and phylogenetic analysis of 16S rDNA gene segments showed populations of Desulfosporosinus and Desulfitobacterium in Penn Mine sediment and laboratory cultures. ?? 2007 Church et al; licensee BioMed Central Ltd.

Geochemical Transactions↗
USGS2018

Non‐linear effect of sea ice: Spectacled Eider survival declines at both extremes of the ice spectrum

Understanding the relationship between environmental factors and vital rates is an important step in predicting a species’ response to environmental change. Species associated with sea ice are of particular concern because sea ice is projected to decrease rapidly in polar environments with continued levels of greenhouse gas emissions. The relationship between sea ice and the vital rates of the Spectacled Eider, a threatened species that breeds in Alaska and Russia and winters in the Bering Sea, appears to be complex. While severe ice can impede foraging for benthic prey, ice also suppresses wave action and provides a platform on which eiders roost, thereby reducing thermoregulation costs. We analyzed a 23‐year mark‐recapture dataset for Spectacled Eiders nesting on Kigigak Island in western Alaska, and tested survival models containing different ice and weather‐related covariates. We found that much of the variation in eider survival could be explained by the number of days per year with >95% sea ice concentration at the Bering Sea core wintering area. Furthermore, the data supported a quadratic relationship with sea ice rather than a linear one, indicating that intermediate sea ice concentrations were optimal for survival. We then used matrix population models to project population trajectories using General Circulation Model (GCM) outputs of daily sea ice cover. GCMs projected reduced sea ice at the wintering area by year 2100 under a moderated emissions scenario (RCP 4.5) and nearly ice‐free conditions under an unabated emissions scenario (RCP 8.5). Under RCP 4.5, stochastic models projected an increase in population size until 2069 coincident with moderate ice conditions, followed by a decline in population size as ice conditions shifted from intermediate to mostly ice‐free. Under RCP 8.5, eider abundance increased until 2040 and then decreased to near extirpation toward the end of the century as the Bering Sea became ice‐free. Considerable uncertainty around parameter estimates for survival in years with minimal sea ice contributed to variation in stochastic projections of future population size, and this uncertainty could be reduced with additional survival data from low‐ice winters.

Alaska↗
USGS2013

Ecosystem services: developing sustainable management paradigms based on wetland functions and processes

In the late nineteenth century and twentieth century, there was considerable interest and activity to develop the United States for agricultural, mining, and many other purposes to improve the quality of human life standards and prosperity. Most of the work to support this development was focused along disciplinary lines with little attention focused on ecosystem service trade-offs or synergisms, especially those that transcended boundaries of scientific disciplines and specific interest groups. Concurrently, human population size has increased substantially and its use of ecosystem services has increased more than five-fold over just the past century. Consequently, the contemporary landscape has been highly modified for human use, leaving behind a fragmented landscape where basic ecosystem functions and processes have been broadly altered. Over this period, climate change also interacted with other anthropogenic effects, resulting in modern environmental problems having a complexity that is without historical precedent. The challenge before the scientific community is to develop new science paradigms that integrate relevant scientific disciplines to properly frame and evaluate modern environmental problems in a systems-type approach to better inform the decision-making process. Wetland science is a relatively new discipline that grew out of the conservation movement of the early twentieth century. In the United States, most of the conservation attention in the earlier days was on wildlife, but a growing human awareness of the importance of the environment led to the passage of the National Environmental Policy Act in 1969. Concurrently, there was a broadening interest in conservation science, and the scientific study of wetlands gradually gained acceptance as a scientific discipline. Pioneering wetland scientists became formally organized when they formed The Society of Wetland Scientists in 1980 and established a publication outlet to share wetland research findings. In comparison to older and more traditional scientific disciplines, the wetland sciences may be better equipped to tackle today’s complex problems. Since its emergence as a scientific discipline, the study of wetlands has frequently required interdisciplinary and integrated approaches. This interdisciplinary/integrated approach is largely the result of the fact that wetlands cannot be studied in isolation of upland areas that contribute surface and subsurface water, solutes, sediments, and nutrients into wetland basins. However, challenges still remain in thoroughly integrating the wetland sciences with scientific disciplines involved in upland studies, especially those involved with agriculture, development, and other land-conversion activities that influence wetland hydrology, chemistry, and sedimentation. One way to facilitate this integration is to develop an understanding of how human activities affect wetland ecosystem services, especially the trade-offs and synergisms that occur when land-use changes are made. Used in this context, an understanding of the real costs of managing for a particular ecosystem service or groups of services can be determined and quantified in terms of reduced delivery of other services and in overall sustainability of the wetland and the landscapes that support them. In this chapter, we discuss some of the more salient aspects of a few common wetland types to give the reader some background on the diversity of functions that wetlands perform and the specific ecosystem services they provide to society. Wetlands are among the most complex ecosystems on the planet, and it is often difficult to communicate to a diverse public all of the positive services wetlands provide to mankind. Our goal is to help the reader develop an understanding that management options can be approached as societal choices where decisions can be made within a spatial and temporal context to identify trade-offs, synergies, and effects on long-term sustainability of wetland ecosystems. This will be especially relevant as we move into alternate climate futures where our portfolio of management options for mitigating damage to ecosystem function or detrimental cascading effects must be diverse and effective.

Book chapter↗
USGS1996

Holocene paleoenvironments of Northeast Iowa

This paper presents the biotic, sedimentary, geomorphic, and climatic history of the upper part of the Roberts Creek Basin, northeastern Iowa for the late—glacial and Holocene, and compares these records with a C—O isotopic sequence from Coldwater Cave, 60 km northwest of Roberts Creek. The biotic record (pollen, vascular plant and bryophyte macrofossils, and insects) is preserved in floodplain alluvium that underlies three constructional surfaces separated by low scarps. Each surface is underlain by a lithologically and temporally distinct alluvial fill. The highest surface is underlain by the Gunder Member of the Deforest Formation, dating from 11 000 to 4000 yr BP; beneath the intermediate level is the Roberts Creek Member, dating from 4000 to 400 yr BP; and the lowest level is underlain by the Camp Creek Member, deposited during the last 380 yr. Pollen and plant macrofossils in the alluvial fill show that a typical late—glacial spruce forest was replaced by Quercus and Ulmus in the early Holocene. This early—to—middle Holocene forest became dominated by mesic elements such as Acer saccharum, Tilia americana, Ostrya virginiana, and Carpinus caroliniana as late as 5500 yr BP; in contrast, the closest sites to the west and north were at their warmest and driest and were covered by prairie vegetation between 6500 and 5500 yr BP. After 5500 yr BP, the forest in the Roberts Creek area was replaced by prairie, as indicated by a rich assemblage of plant macrofossils, although only Ambrosia and Poaceae became abundant in the pollen record. The return of Quercus ≈ 3000 BP (while nonarboreal pollen percentages remained relatively high) indicates that oak savanna prevailed with little change until settlement time. The bryophyte assemblages strongly support the vascular plant record. Rich fen species characteristic of boreal habitats occur only in the late—glacial. They are replaced by a number of deciduous—forest elements when early—to—middle Holocene forests were present, but mosses of forest habitats completely disappear when prairie became dominant. A few deciduous—forest taxa return during the late—Holocene, when oak savanna prevailed. The C—O isotopic record from stalagmite s in Coldwater Cave indicates a relatively stable environment from ≈ 8000 to 5100 yr BP, when the δ 13 C values indicate a change in vegetation dominated by C 3 (predominantly forest) to C 4 (predominantly prairie) plants. About 4900 yr BP, the rise in 18 O values indicates a temperature increase of ≈ 1.5 ° C. The fact that the vegetational change suggested by the δ 13 C values preceded the temperature increase suggests that fire may have been an important factor in converting forest to prairie. Abundant charred seeds and other plant material at Roberts Creek 4830 yr BP support this hypothesis. The 18 O values remain constant from ≈ 5100 to ≈ 3000 yr BP, but the δ 13 C values gradually rise, indicating that soil formed under forest takes at least 2000 yr for its carbon to reach equilibrium after replacement by prairie vegetation. The return of oak to form savanna is reflected in the gradual decline of δ 13 C values in the last 3000 yr BP; O isotopic values drop sharply by ≈ 1 ° C ≈ 2800 yr BP and then were relatively stable. In contrast to the vegetational and isotopic records, the insect assemblages suggest little change in the local environments throughout most of the Holocene. All of the beetle taxa presently occur in eastern Iowa. The relative stability through the Holocene indicates that both open grassland and riparian woodland elements were present throughout. Settlement, land clearing, and land cultivation by EuroAmericans in the region caused rapid erosion of the upland landscape, the deposition of 1—2 m of sediment across the floodplain, a replacement of the native vegetation with ruderal species, a decimation of the native insect fauna, and a degradation of water quality in the stream. These changes in the landscape, vegetation, and insect faunas are as striking as those associated with glacial—interglacial transitions. The timing and direction of changes in the vegetation at Roberts Creek generally correlate well with the carbon and oxygen isotopic record in speleothems at nearby Coldwater Cave and indicate that climate was the main forcing function. However, the contrast between the vegetational change and the stability of the beetle population suggests that climatic changes were subtle. We hypothesize that the factors involved in the Holocene changes were seasonal changes in temperature and precipitation that may not have resulted in much mean annual change. Such changes may have affected the vegetation more than the insect fauna.

Iowa↗
USGS2023

Informing management of recovering predators and their prey with ecological diffusion models

The reintroduction and recovery of predators can be ecologically beneficial as well as socially and economically controversial. However, the growth and expansion of predator populations, and thus their ecological, social, and economic impacts, are not static but rather they vary in space and time. We propose a spatiotemporal statistical modeling framework based on ecological diffusion to better inform the ecology and management of recovering predators and their prey. We demonstrate its utility by applying it to a recovering sea otter ( Enhydra lutris ) population in Southeast Alaska, where sea otters were reintroduced in the late 1960s and have exhibited unprecedented population growth. Estimated parameters yield inferences about movement and population ecology, and our approach provides useful derived quantities, such as local abundance and carrying capacity as well as a quantity we term the equilibrium differential. We used our model to examine how density dependence and carrying capacity of sea otters vary spatially across a region. The diffusion modeling approach we present can be generalized for use in other instances of (re)colonization across taxa to inform management and conservation efforts.

Alaska↗
USGS2025

Implications of physics-based M9 ground motions on liquefaction-induced damage in the Cascadia Subduction Zone: Looking forward and backward

Given the likelihood of future M9 Cascadia Subduction Zone (CSZ) earthquakes, various estimates of the resulting, regional ground motions have been made, including a suite of 30 physics-based simulations that reflect key modeling uncertainties. However, because the last CSZ interface rupture occurred in 1700 CE, the shaking expected in such an event is especially uncertain, as are the impacts to the built and living environments. Like other coseismic impacts, soil liquefaction poses a significant threat and must be considered by any scenario study used to inform planning and response, or to focus mitigation resources. Liquefaction is also notable for its potential to “ground truth” ground-motion estimates, given that its presence or absence in the geologic record can provide constraint on the intensities of shaking in past events. It is thus an important phenomenon looking both forward and backward. Accordingly, using recent physics-based simulations, this study (1) predicts liquefaction in M9 CSZ ruptures at 400 locations in Oregon, Washington, and British Columbia (BC) using an array of cone-penetration-test based models and (2) uses paleoliquefaction evidence at ten sites spanning from Southern Oregon to Vancouver, BC to constrain possible ground-motion intensities experienced in the 1700 CE earthquake. The forward predictions indicate that liquefaction in M9 events could be pervasive in the region and affect numerous population hubs, with the potential for damage across hundreds of square kilometers. The backward analyses suggest that 1700 CE ground-motion intensities may have been less than expected from M9 simulations in some northern portions of the CSZ (e.g. Seattle), given the paucity of 1700 CE liquefaction evidence in these areas. Ultimately, further discovery and analysis of CSZ paleoliquefaction, or lack thereof, will confirm or modify this possibility and the conclusions drawn herein.

Oregon, Washington↗
USGS2011

Patterns of coral disease across the Hawaiian Archipelago: Relating disease to environment

In Hawaii, coral reefs occur across a gradient of biological (host abundance), climatic (sea surface temperature anomalies) and anthropogenic conditions from the human-impacted reefs of the main Hawaiian Islands (MHI) to the pristine reefs of the northwestern Hawaiian Islands (NWHI). Coral disease surveys were conducted at 142 sites from across the Archipelago and disease patterns examined. Twelve diseases were recorded from three coral genera (Porites, Montipora, Acropora) with Porites having the highest prevalence. Porites growth anomalies (PorGAs) were significantly more prevalent within and indicative of reefs in the MHI and Porites trematodiasis (PorTrm) was significantly more prevalent within and indicative of reefs in the NWHI. Porites tissue loss syndrome (PorTLS) was also important in driving regional differences but that relationship was less clear. These results highlight the importance of understanding disease ecology when interpreting patterns of disease occurrence. PorTrm is caused by a parasitic flatworm that utilizes multiple hosts during its life cycle (fish, mollusk and coral). All three hosts must be present for the disease to occur and higher host abundance leads to higher disease prevalence. Thus, a high prevalence of PorTrm on Hawaiian reefs would be an indicator of a healthy coral reef ecosystem. In contrast, the high occurrence of PorGAs within the MHI suggests that PorGAs are related, directly or indirectly, to some environmental co-factor associated with increased human population sizes. Focusing on the three indicator diseases (PorGAs, PorTrm, PorTLS) we used statistical modeling to examine the underlying associations between disease prevalence and 14 different predictor variables (biotic and abiotic). All three diseases showed positive associations with host abundance and negative associations with thermal stress. The association with human population density differed among disease states with PorGAs showing a positive and PorTrm showing a negative association, but no significant explanatory power was offered for PorTLS.

Hawaii↗
USGS1980

Toxicity of five forest insecticides to cutthroat trout and two species of aquatic invertebrates

The Northern Rocky Mountain region has had scattered infestation of the western spruce budworm Christoneura occidentalis since the early 1900's (U.S. DEPARTMENT OF AGRICULTURE (USDA) 1976b). On the basis of aerial surveys in 1975, TUNNOCK et al. (1976), estimated that budworm defoliation occurred on 2,278,804 acres of six National Forests in Montana. Since the use of DDT was banned in 1972, there has been a need to develop alternative insecticides with the efficacy of DDT but without its environmental risk. These insecticides must be effective in controlling the budworm, but should not persist in the environment or be toxic to other organisms. The organophosphate and carbamate insecticides are relatively nonpersistent and generally present only a moderate hazard to fish when applied according to label recommendations. The USDA Forest Service has been investigating the effectiveness of these two classes of insecticides against the budworm, and the Columbia National Fisheries Research Laboratory of the U.S. Fish and Wildlife Service has been cooperating with the Forest Service conducted pilot control projects in eastern Montana in 1975 and 1976 to determine the efficacy and environmental impact of acephate, carbaryl, and trichlorfon in controlling the western budworm (USDA 1976 b). In 1975, a similar type project was carried out in Maine with aminocarb, fenitrothion, and trichlorfon (USDA 1976 a). Acephate, fenitrothion, and trichlorfon (organophosphate insecticides) and aminocarb and carbaryl (carbamate insecticides) were selected for toxicity tests against cutthroat trout ( Salmo clarki ), a stonefly ( Pteronarcella badia ), and a freshwater amphipod ( Gammarus pseudolimnaeus ) edemic in streams of the northern Rocky Mountains. Populations of cutthroat trout inhabit lakes and streams in the Rocky Mountains which include some of the most pristine habitat and fisheries in North America. Pteronarcella and Gammarus provide forage for cutthroat trout and feed on decaying vegetation in riffle areas in streams and rivers. Stonefly naiads and amphipods were selected as test organisms because of their importance as trout food and their wide distribution in mountain stream communities. We determined the effect of various water types representing different biogeographical areas in the Intermountain West on the toxicity of these five forest insecticides.

Bulletin of Environmental Contamination and Toxico↗
USGS2006

An introduced predator alters Aleutian Island plant communities by thwarting nutrient subsidies

The ramifying effects of top predators on food webs traditionally have been studied within the framework of trophic cascades. Trophic cascades are compelling because they embody powerful indirect effects of predators on primary production. Although less studied, indirect effects of predators may occur via routes that are not exclusively trophic. We quantified how the introduction of foxes onto the Aleutian Islands transformed plant communities by reducing abundant seabird populations, thereby disrupting nutrient subsidies vectored by seabirds from sea to land. We compared soil and plant fertility, plant biomass and community composition, and stable isotopes of nitrogen in soil, plants, and other organisms on nine fox-infested and nine historically fox-free islands across the Aleutians. Additionally, we experimentally augmented nutrients on a fox-infested island to test whether differences in plant productivity and composition between fox-infested and fox-free islands could have arisen from differences in nutrient inputs between island types. Islands with historical fox infestations had soils low in phosphorus and nitrogen and plants low in tissue nitrogen. Soils, plants, slugs, flies, spiders, and bird droppings on these islands had low d15N values indicating that these organisms obtained nitrogen from internally derived sources. In contrast, soils, plants, and higher trophic level organisms on fox-free islands had elevated d15N signatures indicating that they utilized nutrients derived from the marine environment. Furthermore, soil phosphorus (but not nitrogen) and plant tissue nitrogen were higher on fox-free than fox-infested islands. Nutrient subsidized fox-free islands supported lush, high biomass plant communities dominated by graminoids. Fox-infested islands were less graminoid dominated and had higher cover and biomass of low-lying forbs and dwarf shrubs. While d15N profiles of soils and plants and graminoid biomass varied with island size and distance from shore, after accounting for these effects differences between fox-infested and fox-free islands still existed. Fertilization over four years caused a 24-fold increase in graminoid biomass and a shift toward a more graminoid dominated plant community typical of fox-free islands. These results indicate that apex predators can influence plant productivity and composition through complex interaction web pathways involving both top-down forcing and bottom-up nutrient exchanges across systems. ?? 2006 by the Ecological Society of America.

Ecological Monographs↗
USGS2007

Coastal systems and low-lying areas

Since the IPCC Third Assessment Report (TAR), our understanding of the implications of climate change for coastal systems and low-lying areas (henceforth referred to as ‘coasts’) has increased substantially and six important policy-relevant messages have emerged. Coasts are experiencing the adverse consequences of hazards related to climate and sea level (very high confidence). Coasts are highly vulnerable to extreme events, such as storms, which impose substantial costs on coastal societies [6.2.1, 6.2.2, 6.5.2]. Annually, about 120 million people are exposed to tropical cyclone hazards, which killed 250,000 people from 1980 to 2000 [6.5.2]. Through the 20th century, global rise of sea level contributed to increased coastal inundation, erosion and ecosystem losses, but with considerable local and regional variation due to other factors [6.2.5, 6.4.1]. Late 20th century effects of rising temperature include loss of sea ice, thawing of permafrost and associated coastal retreat, and more frequent coral bleaching and mortality [6.2.5]. Coasts will be exposed to increasing risks, including coastal erosion, over coming decades due to climate change and sea-level rise (very high confidence). Anticipated climate-related changes include: an accelerated rise in sea level of up to 0.6 m or more by 2100; a further rise in sea surface temperatures by up to 3°C; an intensification of tropical and extra-tropical cyclones; larger extreme waves and storm surges; altered precipitation/run-off; and ocean acidification [6.3.2]. These phenomena will vary considerably at regional and local scales, but the impacts are virtually certain to be overwhelmingly negative [6.4, 6.5.3]. Corals are vulnerable to thermal stress and have low adaptive capacity. Increases in sea surface temperature of about 1 to 3°C are projected to result in more frequent coral bleaching events and widespread mortality, unless there is thermal adaptation or acclimatisation by corals [Box 6.1, 6.4]. Coastal wetland ecosystems, such as saltmarshes and mangroves, are especially threatened where they are sediment starved or constrained on their landward margin [6.4.1]. Degradation of coastal ecosystems, especially wetlands and coral reefs, has serious implications for the well-being of societies dependent on the coastal ecosystems for goods and services [6.4.2, 6.5.3]. ncreased flooding and the degradation of freshwater, fisheries and other resources could impact hundreds of millions of people, and socio-economic costs on coasts will escalate as a result of climate change [6.4.2, 6.5.3]. The impact of climate change on coasts is exacerbated by increasing human-induced pressures (very high confidence). Utilisation of the coast increased dramatically during the 20th century and this trend is virtually certain to continue through the 21st century. Under the SRES scenarios, the coastal population could grow from 1.2 billion people (in 1990) to 1.8 to 5.2 billion people by the 2080s, depending on assumptions about migration [6.3.1]. Increasing numbers of people and assets at risk at the coast are subject to additional stresses due to land-use and hydrological changes in catchments, including dams that reduce sediment supply to the coast [6.3.2]. Populated deltas (especially Asian megadeltas), low-lying coastal urban areas and atolls are key societal hotspots of coastal vulnerability, occurring where the stresses on natural systems coincide with low human adaptive capacity and high exposure [6.4.3]. Regionally, South, South- East and East Asia, Africa and small islands are most vulnerable [6.4.2]. Climate change therefore reinforces the desirability of managing coasts in an integrated manner [6.6.1.3]. Adaptation for the coasts of developing countries will be more challenging than for coasts of developed countries, due to constraints on adaptive capacity (high confidence). While physical exposure can significantly influence vulnerability for both human populations and natural systems, a lack of adaptive capacity is often the most important factor that creates a hotspot of human vulnerability. Adaptive capacity is largely dependent upon development status. Developing nations may have the political or societal will to protect or relocate people who live in low-lying coastal zones, but without the necessary financial and other resources/capacities, their vulnerability is much greater than that of a developed nation in an identical coastal setting. Vulnerability will also vary between developing countries, while developed countries are not insulated from the adverse consequences of extreme events [6.4.3, 6.5.2]. Adaptation costs for vulnerable coasts are much less than the costs of inaction (high confidence). Adaptation costs for climate change are much lower than damage costs without adaptation for most developed coasts, even considering only property losses and human deaths [6.6.2, 6.6.3]. As post-event impacts on coastal businesses, people, housing, public and private social institutions, natural resources, and the environment generally go unrecognised in disaster cost accounting, the full benefits of adaptation are even larger [6.5.2, 6.6.2]. Without adaptation, the high-end sea-level rise scenarios, combined with other climate changes (e.g., increased storm intensity), are as likely as not to render some islands and lowlying areas unviable by 2100, so effective adaptation is urgently required [6.6.3]. The unavoidability of sea-level rise, even in the longer-term, frequently conflicts with present-day human development patterns and trends (high confidence). Sea-level rise has substantial inertia and will continue beyond 2100 for many centuries. Irreversible breakdown of the West Antarctica and/or Greenland ice sheets, if triggered by rising temperatures, would make this long-term rise significantly larger, ultimately questioning the viability of many coastal settlements across the globe. The issue is reinforced by the increasing human use of the coastal zone. Settlement patterns also have substantial inertia, and this issue presents a challenge for long-term coastal spatial planning. Stabilisation of climate could reduce the risks of ice sheet breakdown, and reduce but Chapter 6 Coastal systems and low-lying areas 317 not stop sea-level rise due to thermal expansion [Box 6.6]. Hence, it is now more apparent than it was in the TAR that the most appropriate response to sea-level rise for coastal areas is a combination of adaptation to deal with the inevitable rise, and mitigation to limit the long-term rise to a manageable level [6.6.5, 6.7].

Book chapter↗
USGS2017

Water guns affect abundance and behavior of bigheaded carp and native fish differently

Water guns have shown the potential to repel nuisance aquatic organisms. This study examines the effects of exposure to a 1966.4 cm 3 seismic water gun array (two guns) on the abundance and behavior of Bighead Carp Hypophthalmichthys nobilis , Silver Carp H. molitrix (collectively referred to as bigheaded carp) and native fishes (e.g., Smallmouth Buffalo Ictiobus bubalus ). Water guns were deployed in a channel that connects the Illinois River to backwater quarry pits that contained a large transient population of bigheaded carp. To evaluate the effect of water guns, mobile side-looking split-beam hydroacoustic surveys were conducted before, during and between replicated water gun firing periods. Water guns did not affect abundance of bigheaded carp, but abundance of native fish detected during the firing treatment was 43 and 34% lower than the control and water guns off treatments, respectively. The proximity of bigheaded carp to the water gun array was similar between the water guns on and water guns off treatments. In contrast, the closest detected native fish were detected farther from the water guns during the water guns on treatment (mean ± SE, 32.38 ± 3.32 m) than during the water guns off treatment (15.04 ± 1.59 m). The water gun array had a greater impact on native fish species than on bigheaded carp. Caution should be taken to the extrapolation of these results to other fish species and to fish exposed to water guns in different environments (e.g., reduced shoreline interaction) or exposure to a larger array of water guns, or for use of water guns for purposes other than a barrier.

Illinois↗
USGS2024

Increased mercury concentrations in walleye and yellow perch in lakes invaded by zebra mussels

Zebra mussels ( Dreissena polymorpha ) are invasive species that alter ecosystems and food webs with the potential to affect aquatic mercury cycling and bioaccumulation in fishes, although the effect of zebra mussels on fish tissue mercury has not been tested in inland lakes. We assessed differences in fish tissue mercury concentrations and food webs in Minnesota lakes with and without zebra mussels while controlling for other lake and watershed characteristics. Mercury concentrations in adult walleye ( Sander vitreus ) and yellow perch ( Perca flavescens ) were 72 % and 157 % higher, respectively, in lakes containing zebra mussels compared to uninvaded lakes. Mercury in young of year (age-0) fish was also elevated, with mercury concentrations 97 % and 82 % higher in age-0 walleye and yellow perch, respectively, in zebra mussel lakes. Walleye mercury concentrations exceeded 0.22 ppm — a threshold triggering more restrictive human consumption advisories for sensitive populations — at a 23 % smaller size, and average-sized walleye (420 mm) exceeded this threshold at a rate of 77 % in invaded lakes, compared to 35 % in uninvaded lakes. Walleye and yellow perch relied more on littoral resources in lakes with zebra mussels but did not feed at meaningfully higher trophic levels. Increased fish tissue mercury in lakes invaded by zebra mussels have consequential implications for fisheries and human health.

Minnesota↗
USGS2002

Water-quality data analysis of the upper Gunnison River watershed, Colorado, 1989-99

Water-quality data from October 1969 to December 1999 for both surface water and ground water in the upper Gunnison River watershed were retrieved and compiled from the U.S. Geological Survey National Water Information System and the U.S. Environmental Protection Agency Storage and Retrieval databases. Analyses focused primarily on a subset of these data from October 1989 to December 1999. The upper Gunnison River watershed is located west of the Continental Divide in the Southern Rocky Mountains physiographic province. Surface-water-quality data were compiled for 482 sites in the upper Gunnison River watershed. Most values of surface-water temperature, dissolved oxygen, and pH were within Colorado Department of Public Health and Environment (CDPHE) in-stream standards. Calcium bicarbonate type water was the most spatially dominant water type in the basin. Nutrients were most commonly sampled along the Slate River and East River near Crested Butte and along the Gunnison River from the confluence of the East and Taylor Rivers to the western edge of the watershed. Median ammonia concentrations were low, with many concentrations less than laboratory reporting levels. All nitrate concentrations met the CDPHE in-stream standard of 10 milligrams per liter. More than 30 percent of stream sites with total phosphorus data (23 of 61 sites) had concentrations greater than the U.S. Environmental Protection Agency (USEPA) recommendation for controlling eutrophication. Ammonia concentrations at a site on the Slate River near Crested Butte had a statistically significant upward trend for the 1995–99 period. The Slate River near Crested Butte site is located immediately downstream from the towns of Crested Butte and Mount Crested Butte and may reflect recent population growth or other land-use changes. However, the rate of change of the trend is small (0.017 milligram per liter per year). Although a multiple comparison test showed nitrate concentrations were statistically different between agriculture and forest sites and between agriculture and urban land-use classified sites, median concentrations were low among all land-use settings. Median concentrations of total phosphorus were greatest in rangeland areas and least in urban areas. No significant differences were identified for median concentrations of total phosphorus in agriculture and forest land-use areas. Median concentrations of arsenic, lead, mercury, selenium, and silver were low or below reporting levels throughout the watershed. Aluminum, cadmium, copper, lead, manganese, and zinc concentrations were elevated near the town of Crested Butte and on Henson Creek upstream from Lake City, which may be explained by upstream areas of historical mining. Samples for six trace elements exceeded standards: cadmium, copper, lead, manganese, silver, and zinc. A downward trend (3 micrograms per liter per year) was identified for the dissolved iron concentration at a site on the Gunnison River at County Road 32 downstream from the city of Gunnison. Streambed-sediment samples from areas affected by historical mining also had elevated concentrations of some trace elements. Chlorophyll- a concentrations in samples from Blue Mesa Reservoir and streams in the Crested Butte and Gunnison areas were typical of unenriched to moderately enriched conditions. Median concentrations of 5-day biochemical oxygen demand concentrations for sites between Crested Butte and Blue Mesa Reservoir were less than 2 milligrams per liter. Occasional high (greater than 200 counts per 100 milliliters) concentrations for fecal coliform were determined at selected sites within the study area. However, median concentrations were less than 100 counts per 100 milliliters except for the Squaw Creek and Cimarron River areas in the western part of the watershed. Ground-water-quality data have been collected by the U.S. Geological Survey from 99 wells. Many wells were completed in aquifers composed of Holocene-age valley fill and alluvium. Most field properties were within the USEPA Secondary Drinking Water Regulations (SDWR) range for treated drinking water, except for 2 (of 40) pH samples. Calcium bicarbonate was the predominant water type in nearly all aquifers except for the aquifers composed of volcanic rock, which had more sodium and sulfate mixed water types. Wells with sulfate concentrations exceeding the SDWR of 250 milligrams per liter were completed in aquifers composed of volcanic rock near Lake City. Dissolution and oxidation of sulfide minerals in these aquifers may explain the elevated sulfate concentrations in ground water at these locations. Nutrient concentrations in ground water were generally low, and median concentrations for ammonia, nitrite, and dissolved phosphorus were below reporting levels. All nitrate concentrations in the samples were below the USEPA drinking-water maximum contaminant level of 10 mg/L. No statistical difference was found in nitrate concentrations among the four land-use classifications (agriculture, forest, rangeland, and urban). Trace elements in ground water were generally below the USEPA SDWR. Three iron samples exceeded the USEPA SDWR of 300 micrograms per liter at two wells located near the city of Gunnison and at a well south of the town of Powderhorn near the Cebolla River. Nine of 39 manganese samples exceeded the USEPA SDWR of 50 micrograms per liter and were collected from aquifers composed of Holocene-age valley fill and alluvium near Gunnison and Crested Butte and in one well near the Cebolla River. Radon gas is a natural radioactive decay product of uranium. All 39 radon samples collected from ground water in the watershed exceeded the proposed USEPA drinking-water maximum contaminant level of 300 picocuries per liter and ranged from 426 to 3,830 picocuries per liter.

Colorado↗
USGS2025

Sparse genetic data limit biodiversity assessments in protected areas globally

Global conservation targets include protecting genetic diversity within species. Yet few studies have assessed whether protected areas (PAs) include genetically diverse populations across species globally. A first step is understanding the availability of population genetic data that could be used in these assessments. We surveyed georeferenced population-level nuclear (as opposed to mitochondrial or plastid-based) genetic data across continents and marine biomes (36,354 populations, 2809 species) and found substantial geographic and taxonomic gaps. Most data were concentrated in Europe and North America, with major gaps in Africa and Asia. For most taxonomic groups, data were available for <1% of described species. Globally, 52.08% of the total areal extent of PAs lacked genetically sampled populations. These gaps in data availability highlight the need for targeted genetic data collection, harmonization, and sharing to improve genetic diversity monitoring and conservation planning. Combined with proxy-based genetic indicators, such data are needed to inform PA assessments, bolster area-based conservation initiatives like 30 × 30, and support achievement of global genetic conservation targets.

Frontiers in Ecology and the Environment↗
USGS2009

Forecasting urban growth across the United States-Mexico border

The sister-city area of Nogales, Arizona, and Nogales, Sonora, Mexico, is known collectively as Ambos (both) Nogales. This area was historically one city and was administratively divided by the Gadsden Purchase in 1853. These arid-lands have limited and sensitive natural resources. Environmental planning can support sustainable development to accommodate the predicted influx of population. The objective of this research is to quantify the amount of predicted urban growth for the Ambos Nogales watershed to support future planning for sustainable development. Two modeling regimes are explored. Our goal is to identify possible growth patterns associated with the twin-city area as a whole and with the two cities modeled as separate entities. We analyzed the cross-border watershed using regression analysis from satellite images from 1975, 1983, 1996, and 2002 and created urban area classifications. We used these classifications as input to the urban growth model, SLEUTH, to simulate likely patterns of development and define projected conversion probabilities. Model results indicate that the two cities are undergoing very different patterns of change and identify locations of expected growth based on historical development. Growth in Nogales, Arizona is stagnant while the urban area in Nogales, Sonora is exploding. This paper demonstrates an application that portrays how future binational urban growth could develop and affect the environment. This research also provides locations of potential growth for use in city planning.

Computers, Environment and Urban Systems↗
USGS2021

Zircon surface crystallization ages for the extremely reduced magmatic products of the Millennium Eruption, Changbaishan Volcano (China/North Korea)

The Millennium Eruption (ME) of Changbaishan volcano (Baitoushan, Paektu) at 946 CE (Common Era) is one of the largest explosive eruptions on Earth during Holocene times. We date unpolished zircon crystal faces from diverse ME products collected from the southern side of Changbaishan volcano where the ME pumice and welded and non-welded pyroclastic flow deposits (PFD) are better exposed. All zircons from a pumice sample of the southern caldera rim and the youngest (Group 1) zircons from a welded pumiceous PFD sample yield an isochron crystallization age of 0.7 ± 1.8 ka (2σ). Zircons from the welded pumiceous PFD sample yield additional two age groups at ~10 ka and ~ 100 ka. Zircons from a non-welded charcoal-containing PFD have only one age population at 100 ka. Our work shows that different eruption products from ME have different zircon surface age distributions and may tap different levels of a zoned felsic magma chamber. In addition, the results indicate that ion microprobe U-Th dating of zircon crystal surfaces from ME pumices can effectively date the Millennium eruption age. Previously reported zircon U-series ages for Qixangzhan eruption (12.2 ± 1.1 ka, 2σ) and Yuanchi eruption (7.3 ± 1.8 ka, 2σ) at Changbaishan are also likely to date their respective eruption ages. The occurrence of 100 ka zircons in welded and non-welded PFDs reveals an important magmatic event for the Changbaishan volcano. Zircon and Fe-rich clinopyroxene crystallized at similar temperature at 770–750 °C, indicative of early zircon crystallization in peralkaline magmas. Another important result is the extremely low oxygen fugacity (fO 2 = ΔFMQ-2) of the Changbaishan samples. Minerals in ME magmas were crystallized under some of the most reducing magmatic environments on Earth. Highly reducing conditions of magmas from Changbaishan supports a continental rift setting and argues against significant involvements of subduction-related oxidizing fluids during magma genesis.

Changbaishan Volcano↗
USGS2023

An assessment of the relation between metal contaminated sediment and freshwater mussel populations in the Big River, Missouri

The Big River in southeast Missouri drains the largest historical lead mining area in the United States. Ongoing releases of metal contaminated sediments into this river are well documented and are suspected of suppressing freshwater mussel populations. We characterized the spatial extent of metal contaminated sediments and evaluated its relationship with mussel populations in the Big River. Mussels and sediments were collected at 34 sites with potential metal effects and 3 reference sites. Analysis of sediment samples showed that lead (Pb) and zinc (Zn) concentrations were 1.5 to 65 times greater than background concentrations in the reach extending 168 km downstream from Pb mining releases. Mussel abundance decreased acutely downstream from these releases where sediment Pb concentrations were highest and increased gradually as Pb sediment concentrations attenuated downstream. We compared current species richness with historical survey data from three reference rivers with similar physical habitat characteristics and human effects, but without Pb-contaminated sediment. Big River species richness was on average about one-half that expected based on reference stream populations and was 70–75 % lower in reaches with high median Pb concentrations. Sediment Zn and cadmium, and particularly Pb, had significant negative correlations with species richness and abundance. The association of sediment Pb concentrations with mussel community metrics in otherwise high-quality habitat indicates that Pb toxicity is likely responsible for depressed mussel populations observed within the Big River. We used concentration-response regressions of mussel density verses sediment Pb to determine that the Big River mussel community is adversely affected when sediment Pb concentrations are above 166 ppm, the concentration associated with 50 % decreases in mussel density. Based on this assessment of metals concentrations sediment and mussel fauna, our findings indicate that sediment in approximately 140 km of the Big River with suitable habitat has a toxic effect to mussels.

Missouri↗
USGS2013

Genetic relationships among some subspecies of the Peregrine Falcon ( Falco peregrinus L.), inferred from mitochondrial DNA control-region sequences

The ability to successfully colonize and persist in diverse environments likely requires broad morphological and behavioral plasticity and adaptability, and this may partly explain why the Peregrine Falcon ( Falco peregrinus ) exhibits a large range of morphological characteristics across their global distribution. Regional and local differences within Peregrine Falcons were sufficiently variable that ∼75 subspecies have been described; many were subsumed, and currently 19 are generally recognized. We used sequence information from the control region of the mitochondrial genome to test for concordance between genetic structure and representatives of 12 current subspecies and from two areas where subspecies distributions overlap. Haplotypes were broadly shared among subspecies, and all geographic locales shared a widely distributed common haplotype (FalconCR2). Haplotypes were distributed in a star-like phylogeny, consistent with rapid expansion of a recently derived species, with observed genetic patterns congruent with incomplete lineage sorting and/or differential rates of evolution on morphology and neutral genetic characters. Hierarchical analyses of molecular variance did not uncover genetic partitioning at the continental level, despite strong population-level structure ( F ST = 0.228). Similar analyses found weak partitioning, albeit significant, among subspecies ( F CT = 0.138). All reconstructions placed the hierofalcons' (Gyrfalcon [ F. rusticolus ] and Saker Falcon [ F. cherrug ]) haplotypes in a well-supported clade either basal or unresolved with respect to the Peregrine Falcon. In addition, haplotypes representing Taita Falcon ( F. fasciinucha ) were placed within the Peregrine Falcon clade.

The Auk↗