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At least 1,117 records · Page 62Linked to original sources

USGS2022

Recent declines in genetic diversity with limited dispersal among coastal cactus wren populations in San Diego County, California

Habitat loss and fragmentation can lead to smaller and more isolated populations and reduce genetic diversity and evolutionary potential. Conservation programs can benefit from including monitoring of genetic factors in fragmented populations to help inform restoration and management. We assessed genetic diversity and structure among four major populations of the Cactus Wren ( Campylorhynchus brunneicapillus ) in San Diego County in 2011–2012 and again in 2017–2019, using 22 microsatellite loci. We found a significant decline in heterozygosity in one population (San Pasqual) and a decline in allelic richness and effective population size in another (Sweetwater). Genetic diversity in the remaining two populations was not significantly different over time. Local diversity declined despite evidence of dispersal among some populations. Approximately 12% of genetically determined family groups (parents, offspring, siblings) included one or more members sampled in different territories with distances ranging from 0.2 to 10 km. All but one inferred dispersal events occurred within the same genetic population. Population structure remained relatively stable, although genetic differentiation tended to increase in the later sampling period. Simulations suggest that at currently estimated effective sizes, populations of Cactus Wrens will continue to lose genetic diversity for many generations, even if gene flow among them is enhanced. However, the rate of loss of heterozygosity could be reduced with increased gene flow. Habitat restoration may help bolster local population sizes and allelic richness over the long term, whereas translocation efforts from source populations outside of San Diego may be needed to restore genetic diversity in the short term.

California↗

USGS1990

U.S. Geological Survey National Computer Technology Meeting; Program and abstracts, May 7-11, 1990

he Water Resources Division of the U.S. Geological Survey has made major advancements in the use of computer technology to meet the Survey‘s mission of providing the hydrologic information and understanding needed for the optimum use and management of the Nation’s water resources. The Division requires substantial computer technology to process, store, and analyze data from about 60,000 sites. To meet this workload, the Division organized its computer resources in 1982 through the Distributed Information System (DIS) Program Office, which manages the Division's national network of computers. The DIS is designed to provide computer resources in support of the Division’s current and future activities -acquisition and storage of hydrologic information, hydrologic data analysis, geographic information systems, reports and electronic report processing, and administration. The Water Resources Division sponsored the first DIS Site Administrators Meeting in March 1984 in Denver, Colorado, and a second meeting in October 198.5 in Hyannis, Massachusetts. The thrust of the first two national meetings was the training of Water Resources Division personnel in the use and administration of the Division’s computer hardware and software. Starting with the third meeting, which was held in Atlanta, Georgia, in May 1987, the name was changed to the National Computer Technology Meeting because the format evolved to include presentation of papers prepared by computer and scientific personnel in the Division. These papers document work done in the field of computer science as applied to hydrology, including the design and use of geographic information systems, use of nationally distributed software, the development of procedures for data-base management, and research papers on the expanding field of computer technology. Training continues to be a major part of the National Computer Technology Meeting. This year’s meeting includes training on the use of UNIX operating system, UNIX system administration and security, the C programming language, local area networking, as well as a publication seminar. This report includes abstracts for papers and posters that have been accepted for presentation at the Fifth National Computer Technology Meeting.

Open-File Report↗

USGS2024

Incorporating climate change into restoration decisions: Perspectives from dam removal practitioners

Incorporating climate change into conservation and restoration decisions is increasingly important for natural resource managers and restoration practitioners to effectively address the underlying drivers of ecosystem change. Small dam removal is an example of a restoration tool that may offer multiple socioeconomic and ecological benefits in streams, including promoting climate resilience. With the pace of dam removals increasing, practitioners and researchers are well-poised to incorporate climate change into future dam removal decisions. Therefore, we surveyed dam removal practitioners across 14 states in the eastern United States to understand current practices of small dam removals, factors driving restoration decisions, and how climate change knowledge is incorporated into these decisions. We also aimed to identify barriers to and opportunities for knowledge exchange between practitioners and researchers. Of the 100 respondents, most (79%) consider climate change in their dam removal decisions to some extent. Despite this, many reported a lack of clear, relevant, and accessible data linking small dam removal to climate resilience benefits. Dam removal practitioners also indicated that they most often rely on climate change information garnered from conversations with colleagues, rather than from scientific research products. These results suggest that the co-production of relevant, salient research questions and readily accessible and interpretable research products (e.g., technical summaries, open access articles) may encourage practitioners to incorporate climate change science more consistently and efficiently into dam removal decisions. These findings may also translate to other stream restoration efforts to inform knowledge exchange and improve restoration outcomes in a changing climate.

Connecticut, Delaware, Kentucky, Maine, Maryland, ↗

USGS2016

Integrated groundwater management: An overview of concepts and challenges

Managing water is a grand challenge problem and has become one of humanity’s foremost priorities. Surface water resources are typically societally managed and relatively well understood; groundwater resources, however, are often hidden and more difficult to conceptualize. Replenishment rates of groundwater cannot match past and current rates of depletion in many parts of the world. In addition, declining quality of the remaining groundwater commonly cannot support all agricultural, industrial and urban demands and ecosystem functioning, especially in the developed world. In the developing world, it can fail to even meet essential human needs. The issue is: how do we manage this crucial resource in an acceptable way, one that considers the sustainability of the resource for future generations and the socioeconomic and environmental impacts? In many cases this means restoring aquifers of concern to some sustainable equilibrium over a negotiated period of time, and seeking opportunities for better managing groundwater conjunctively with surface water and other resource uses. However, there are many, often-interrelated, dimensions to managing groundwater effectively. Effective groundwater management is underpinned by sound science (biophysical and social) that actively engages the wider community and relevant stakeholders in the decision making process. Generally, an integrated approach will mean “thinking beyond the aquifer”, a view which considers the wider context of surface water links, catchment management and cross-sectoral issues with economics, energy, climate, agriculture and the environment. The aim of the book is to document for the first time the dimensions and requirements of sound integrated groundwater management (IGM). The primary focus is on groundwater management within its system, but integrates linkages beyond the aquifer. The book provides an encompassing synthesis for researchers, practitioners and water resource managers on the concepts and tools required for defensible IGM, including how IGM can be applied to achieve more sustainable socioeconomic and environmental outcomes, and key challenges of IGM. The book is divided into five parts: integration overview and problem settings; governance; socioeconomics; biophysical aspects; and modelling and decision support. However, IGM is integrated by definition, thus these divisions should be considered a convenience for presenting the topics rather than hard and fast demarcations of the topic area.

Book chapter↗

USGS2003

Pesticides, polycyclic aromatic hydrocarbons, and polychlorinated biphenyls in transport in two Atlantic coastal plain tributaries and loadings to Chesapeake Bay

Concentrations of current-use pesticides, polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and organochlorine (OC) insecticides were determined above the reach of tide in the Chesterville Branch and Nanticoke River on the eastern shore of Chesapeake Bay during base-flow and storm-flow hydrologic regimes to evaluate mass transport to Chesapeake Bay. The two rivers monitored showed relatively high concentrations of atrazine, simazine, alachlor, and metolachlor in comparison to previously investigated western shore tributaries, and reflected the predominant agricultural land use in the eastern shore watersheds. The four current use pesticides showed the greatest seasonal contribution to annual loadings to tidal waters of Chesapeake Bay from the two rivers, and the relative order of annual loadings for the other contaminant classes was PAHs > PCBs > OC insecticides. Annual loadings normalized to the landscape areas of selected Chesapeake Bay watersheds showed correlations to identifiable source areas, with the highest pesticide yields (g/km2/yr) occurring in eastern shore agricultural landscapes, and the highest PAH yields derived from urban regions.

Journal of Environmental Science and Health - Part↗

USGS1989

Translocation as a species conservation tool: Status and strategy

Surveys of recent (1973 to 1986) intentional releases of native birds and mammals to the wild in Australia, Canada, Hawaii, New Zealand, and the United States were conducted to document current activities, identify factors associated with success, and suggest guidelines for enhancing future work. Nearly 700 translocations were conducted each year. Native game species constituted 90 percent of translocations and were more successful (86 percent) than were translocations of threatened, endangered, or sensitive species (46 percent). Knowledge of habitat quality, location of release area within the species range, number of animals released, program length, and reproductive traits allowed correct classification of 81 percent of observed translocations as successful or not.

Science↗

USGS2020

Flood-inundation maps for the Little Calumet River from Lansing to South Holland, Illinois, 2020

Digital flood-inundation maps for about an 8-mile reach of the Little Calumet River, Illinois, were created by the U.S. Geological Survey (USGS) in cooperation with the U.S. Army Corps of Engineers. The flood-inundation maps, which can be accessed through the USGS Flood Inundation Mapping Science website at https://www.usgs.gov/mission-areas/water-resources/science/flood-inundation-mapping-fim-program , depict estimates of the areal extent and depth of flooding corresponding to selected water levels (stages) at three USGS streamgages: Little Calumet River at South Holland, Ill. (USGS station 05536290); Little Calumet River at Munster, Indiana (USGS station 05536195); and Thorn Creek at Thornton, Ill. (USGS station 05536275). Near-real-time stages at these streamgages may be obtained on the internet from the USGS National Water Information System at https://doi.org/10.5066/F7P55KJN or the National Weather Service Advanced Hydrologic Prediction Service at https://water.weather.gov/ahps/ , which also forecasts flood hydrographs at these sites. Flood profiles were computed for the stream reaches using a one-dimensional unsteady flow step-backwater hydraulic model. The model performance was evaluated using historical streamflow measurements and the most current stage-discharge relations at the USGS streamgages at Little Calumet River at South Holland, Ill.; Little Calumet River at Munster, Ind.; and Thorn Creek at Thornton, Ill. The model was used to compute 24 water-surface profiles at 1-foot intervals referenced to the streamgage datum and ranging from bankfull to about the 0.2-percent annual-exceedance probability flood (500-year recurrence interval flood). The simulated water-surface profiles were then combined with a geographic information system digital elevation model (derived from light detection and ranging data having a 0.6-foot vertical accuracy and a 2-foot horizontal resolution) to delineate the area flooded at each water level. The availability of these maps, along with internet information regarding current stage from USGS streamgages and forecasted high-flow stages from the National Weather Service, will provide emergency management personnel and residents with information that is critical for flood-response activities such as evacuations and road closures, as well as for postflood recovery efforts.

Illinois↗

USGS2023

Long-term water-quality constituent trends in the Little Arkansas River, south-central Kansas, 1995–2021

The Equus Beds aquifer and Cheney Reservoir are primary sources for the city of Wichita’s current (2023) water supply. The Equus Beds aquifer storage and recovery (ASR) project was developed by the city of Wichita in the early 1990s to meet future water demands using the Little Arkansas River as an artificial aquifer recharge water source during above-base-flow conditions. Little Arkansas River water is removed from the river at an ASR Facility intake structure, treated using National Primary Drinking Water Regulations as a guideline, and is infiltrated into the Equus Beds aquifer through recharge basins or injected into the aquifer through recharge wells for later use. The U.S. Geological Survey, in cooperation with the city of Wichita, completed this study to quantify and characterize Little Arkansas River water-quality data. Data in this report can be used to evaluate changing conditions, provide science-based information for decision making, and help meet regulatory requirements. Continuous (hourly) physicochemical properties were measured, and discrete water-quality samples were collected from three Little Arkansas River sites located along the easternmost extent of the Equus Beds aquifer during 1995 through 2021 over a range of streamflow conditions. The Little Arkansas River at Highway 50 near Halstead, Kansas, streamgage (U.S. Geological Survey station 07143672; hereafter referred to as the “Highway 50 site”) is located upstream from the other two sites, and the Little Arkansas River near Sedgwick, Kans., streamgage (U.S. Geological Survey station 07144100; hereafter referred to as the “Sedgwick site”) is located downstream from the other two sites; these two sites bracket most of the easternmost part of the Equus Beds aquifer. The Little Arkansas River upstream of ASR Facility near Sedgwick, Kans., streamgage (U.S. Geological Survey station 375350097262800; hereafter referred to as the “Upstream ASR site”) is located between the Highway 50 and Sedgwick sites, about 14.7 river miles (mi) downstream from the Highway 50 site, about 1.7 river mi upstream from the Sedgwick site, and immediately upstream from the ASR Facility intake structure. Surrogate models for water-quality constituents of interest (including bromide, dissolved organic carbon, 2-chloro-4-isopropylamino-6-amino- s -triazine [deethylatrazine], atrazine, and metolachlor) were updated or developed using continuously measured and concomitant discrete data. These surrogate models, along with previously developed regression models, were used to compute concentrations (at the Highway 50, Sedgwick, and Upstream ASR sites) and loads (at the Highway 50 and Sedgwick sites) during the study period. Federal criteria were used to evaluate water quality. Where applicable, water-quality data were compared to Federal national drinking-water regulations. Flow-normalized water-quality constituent trends were evaluated using Weighted Regressions on Time, Discharge, and Season (WRTDS) statistical models and water-quality trends were described using WRTDS bootstrap tests. Continuously computed primary ion concentrations were generally larger at the Highway 50 site compared to the Sedgwick site. During the study period, the Federal secondary maximum contaminant level (SMCL) for dissolved solids was exceeded 57 percent of the time at the Highway 50 site and 38 percent of the time at the Sedgwick site. Computed bromide concentrations were larger at the Highway 50 site and exceeded the city of Wichita treatment threshold about 70, 21, and 19 percent of the time at the Highway 50, Sedgwick, and Upstream ASR sites, respectively. Chloride concentrations exceeded the Federal SMCL about 16 percent of the time at the Highway 50 site and did not exceed the SMCL at the Sedgwick site. Continuous arsenic concentrations exceeded the Federal Maximum Contaminant Level (MCL) 9 to 15 percent of the time at the Sedgwick and Highway 50 sites, respectively, during the study. Atrazine concentrations exceeded the Federal MCL 10 percent of the time at the Highway 50 and Sedgwick sites and 14 percent of the time at the Upstream ASR site during the study; computed glyphosate concentrations at the Sedgwick site never exceeded the MCL during the study. Little Arkansas River flow-normalized primary ion concentrations during 1995 through 2021 generally had downward trends and decreases were generally larger at the Highway 50 site compared to the Sedgwick site. Dissolved solids and chloride concentrations decreased at the Highway 50 and Sedgwick sites. Bromide had no trend at the Highway 50 site and a downward trend at the Sedgwick site. Nitrate plus nitrite and total phosphorus concentrations had upward trends at the Highway 50 site but downward trends at the Sedgwick site, whereas total organic carbon had upward trends at both sites. Nitrate plus nitrite, total nitrogen, total phosphorus, and total organic carbon fluxes had upward trends at the Highway 50 and Sedgwick sites. Suspended-sediment concentrations had an upward trend at the Highway 50 site and had no trend at the Sedgwick site. Arsenic concentrations had downward trends at the Highway 50 and Sedgwick sites. About one-quarter to one-half of the Little Arkansas River loads, including nutrients and sediment, were transported during 1 percent of the time during the study. Because streamflows are highly sensitive to climatic variation and an increase of extreme precipitation events in the Great Plains is expected, similar disproportionately large pollutant loading events may increase into the future. Continuous measurement of physicochemical properties in near-real time allowed characterization of Little Arkansas River surface water during conditions and time scales that would not have been possible otherwise and served as a complement to discrete water-quality sampling. Continuation of this water-quality monitoring will provide data to characterize changing conditions in the Little Arkansas River and possibly identify new and changing trends. Information in this report allows the city of Wichita to make informed municipal water-supply decisions using past and present water-quality conditions and trends in the watershed.

Kansas↗

USGS1980

Handbook of acute toxicity of chemicals to fish and aquatic invertebrates : summaries of toxicity tests conducted at Columbia National Fisheries Research Laboratory, 1965-78

Acute toxicity is a major subject of research at Columbia National Fisheries Research Laboratory for evaluating the impact of toxic chemicals on fishery resources. The Laboratory has played a leading role in developing research technology for toxicity testing and data interpretation. In 1965-78, more than 400 chemicals were tested against a variety of invertebrates and fish species representative of both cold- and warm-water climates. The use of acute toxicity tests for assessing the potential hazard of chemical contaminants to aquatic organisms is well documented (Boyd 1957; Henderson et al. 1960; Sanders and Cope 1966; Macek and McAllister 1970). Static acute toxicity tests provide rapid and (within limits) reproducible concentration-response curves for estimating toxic effects of chemicals on aquatic organisms. These tests provide a database for determining relative toxicity of a large number of chemicals to a variety of species and for estimating acute effects of chemical spills on natural aquatic systems; they also assist in determining priority and design of additional toxicity studies. Acute toxicity tests usually provide estimates of the exposure concentration causing 50% mortality (LC50) to test organisms during a specified period of time. For certain invertebrates, the effective concentration is based on immobilization, or some other identifiable endpoint, rather than on lethality. The application of the LC50 has gained acceptance among toxicologists and is generally the most highly rated test for assessing potential adverse effects of chemical contaminants to aquatic life (Brungs and Mount 1978; American Institute for Biological Sciences 1978 a ). The literature contains numerous papers dealing with the acute toxicity of chemicals to freshwater organisms. However, there is a tremendous need for a concise compendium of toxicity data covering a large variety of chemicals and test species. This Handbook is a compilation of a large volume of acute toxicity data from the Columbia Laboratory and its field laboratories. It presents definitive acute toxicity data on 271 chemicals tested against a variety of freshwater invertebrates and fishes. The chemicals represent all major groups of pesticides, as well as numerous industrial chemicals. This compilation should serve as a useful database for the many agencies and organizations dealing with research and management programs concerned with the impact of chemicals on aquatic resources. The Columbia Laboratory has played a major role in developing currently used standard methodology for static acute toxicity testing. The use of standardized methodology greatly reduces variation in results. The data presented here have been carefully scrutinized to eliminate tests that failed to follow acceptable procedures. Handling of test organisms and procedures for static toxicity tests followed those described by Lennon and Walker (1964) and Macek and McAllister (1970), and conform well with those recommended by Brauhn and Schoettger (1975) and the Committee on Methods for Toxicity Tests with Aquatic Organisms (1975). The species of fish and invertebrates that were tested are listed in phylogenetic order in Tables 1 and 2. Fish were obtained from Federal and State hatcheries as either eggs or fry. Original stocks of invertebrates were collected and cultured from wild populations with no known source of contamination; these populations were replenished regularly. The invertebrates were cultured in the Laboratory by methods similar to those described by Sanders and Cope (1966). Test chemicals usually consisted of technical or analytical grade samples of known purity. Formulations of the chemicals were also tested when available. When purity of test chemicals was known, all calculated concentrations were based on percent active ingredients. Stock solutions were prepared immediately before each test, with commercial grade acetone as the carrier solvent. Occasionally, ethanol or dimethyl-formamide was substituted. Solvent concentrations did not exceed 0.5 mL/L in final dilution water. Test water (dilution water) was reconstituted from deionized water of at least 10 6 ohms resistivity by the addition of appropriate reagent grade chemicals (Marking 1969). Water was buffered to maintain a pH of 7.2 to 7.5, an alkalinity of 30 to 35 mg/L, and a hardness of 40 to 50 mg/L as CaCO 3 . Test water was mixed thoroughly and aerated before transfer into test chambers. Fish were acclimated to dilution water by gradually changing the water in acclimated tanks from 100% well water to 100% reconstituted water over a 1- to 3-day period at the desired testing temperature. Invertebrates were acclimated from well water to dilution water over a 4- to 6-h period. Toxicity tests were conducted under static conditions without aeration, and the organisms were not fed during acclimation or testing. Temperature of test solutions was maintained within ± 1°C of that required for a given test. Toxicity tests with fish were conducted in 18.9-liter (5-gal) wide-mouthed jars containing 15 liters of test solution. Fingerling fish weighing 0.2 to 1.5 g were tested at each concentration. Caution was taken not to exceed 0.8 g of test organisms per liter of solution. Duplicate test chambers were used to accommodate larger fish. Test chambers varied in size for invertebrates, depending on the species used; volume of test solution ranged from 0.25 to 4 liters. At least 10 organisms were exposed to each concentration for all definitive tests. At least six concentrations were used per toxicity test. The tests began upon initial exposure to the toxicant and continued for 96 h. Immobilization tests with invertebrates were conducted for only 48 h. The number of dead or affected organisms in each test chamber were recorded and the dead organisms were removed every 24 h; general observations on the condition of test organisms were also recorded at these times. Toxicity data were analyzed by a statistical method described by Litchfield and Wilcoxon (1949) to determine LC50 (theoretical estimate of the concentration lethal to 50% of the test animals) and 95% confidence intervals. This method is recommended by the American Public Health Association (1971) and by Sprague (1969) for determining median lethal concentrations. The procedure is easily modified for computing a single LC50 when replicate tests are performed.

Resource Publication↗

USGS2006

Finding common ground in large carnivore conservation: mapping contending perspectives

Reducing current conflict over large carnivore conservation and designing effective strategies that enjoy broad public support depend on a better understanding of the values, beliefs, and demands of those who are involved or affected. We conducted a workshop attended by diverse participants involved in conservation of large carnivores in the northern U.S. Rocky Mountains, and used Q methodology to elucidate participant perspectives regarding "problems" and "solutions". Q methodology employs qualitative and quantitative techniques to reveal the subjectivity in any situation. We identified four general perspectives for both problems and solutions, three of which (Carnivore Advocates, Devolution Advocates, and Process Reformers) were shared by participants across domains. Agency Empathizers (problems) and Economic Pragmatists (solutions) were not clearly linked. Carnivore and Devolution Advocates expressed diametrically opposed perspectives that legitimized different sources of policy-relevant information ("science" for Carnivore Advocates and "local knowledge" for Devolution Advocates). Despite differences, we identified potential common ground focused on respectful, persuasive, and creative processes that would build understanding and tolerance. ?? 2006 Elsevier Ltd. All rights reserved.

Environmental Science and Policy↗

USGS2002

Seismic-reflection profiles of the central part of the Clarendon-Linden fault system of western New York in relation to regional seismicity

Geological and geophysical research in upstate New York, with few exceptions, has not definitively associated seismicity with specific Proterozoic basement or Paleozoic bedrock structures. The central part of the Clarendon-Linden fault system (CLFS) between Batavia and Dale, NY is one of those exceptions where seismicity has been studied and has been spatially associated with structure. The CLFS is either a complex system of long faults with associated shorter branches and parallel segments, or a region of many short faults aligned north-south from the Lake Ontario shore southward to Allegany County, NY. Interpretation of 38 km of Vibroseis and approximately 56 km of conventional seismic-reflection data along 13 lines suggests that the CLFS is a broad zone of small faults with small displacements in the lower Paleozoic bedrock section that is at least 77 km long and 7-17 km wide and spatially coincident with a northtrending geophysical (combined aeromagnetic and gravity) lineament within the basement. The relative offset across the faults of the system is more than 91 m near Attica, NY. The CLFS is the expression of tectonic crustal adjustments within the Paleozoic rock above the boundary of two basement megablocks of differing petrologic provinces and differing earthquake characteristics that forms the eastern side of the Elzevir-Frontenac boundary zone. Deep seismic-reflection profiles display concave-eastward listric faults that probably merge at depth near the mid-crustal boundary layer. An interpretive vertical section provides the setting for refined definitions of the CLFS, its extensions at depth and its relation to seismicity. Most modern seismicity in western New York and the Niagara Peninsula of Ontario occurs in apparent patterns of randomly dispersed activity. The sole exception is a line of seven epicenters of small earthquakes that trend east from Attica, NY into the Rochester basement megablock. Earthquakes may be triggered at the intersections of north- and east-trending brittle faults within the Niagara basement megablock. Current interpretations of the mechanisms for earthquake generation in western New York and the Niagara Peninsula of Ontario require conservative estimates of seismic hazards that assume that an earthquake the size of the 1929 Attica, NY, event (Mb = 5.2) or larger could occur anywhere in the Eastern Great Lakes Basin (EGLB). The broad zone of small-displacement faults that marks the CLFS in the lower Paleozoic sedimentary section and the uppermost basement may not provide the structural environment for generation of earthquakes in western New York. If this interpretation is correct, most seismicity is generated within the Niagara basement megablock beneath or west of the CLFS. Consequently, we may have to look to the deeper tectonic regime of basement megablocks to understand the distribution of modern seismicity in the EGLB. ?? 2002 Elsevier Science B.V. All rights reserved.

Tectonophysics↗

USGS2020

Benthic habitat is an integral part of freshwater Mysis ecology

Diel vertical migration (DVM) is common in aquatic organisms. The trade‐off between reduced predation risk in deeper, darker waters during the day and increased foraging opportunities closer to the surface at night is a leading hypothesis for DVM behaviour. Diel vertical migration behaviour has dominated research and assessment frameworks for Mysis , an omnivorous mid‐trophic level macroinvertebrate that exhibits strong DVM between benthic and pelagic habitats and plays key roles in many deep lake ecosystems. However, some historical literature and more recent evidence indicate that mysids also remain on the bottom at night, counter to expectations of DVM. We surveyed the freshwater Mysis literature using Web of Science (WoS; 1945–2019) to quantify the frequency of studies on demographics, diets, and feeding experiments that considered, assessed, or included Mysis that did not migrate vertically but remained in benthic habitats. We supplemented our WoS survey with literature searches for relevant papers published prior to 1945, journal articles and theses not listed in WoS, and additional references known to the authors but missing from WoS (e.g. only 47% of the papers used to evaluate in situ diets were identified by WoS). Results from the survey suggest that relatively little attention has been paid to the benthic components of Mysis ecology. Moreover, the literature suggests that reliance on Mysis sampling protocols using pelagic gear at night provides an incomplete picture of Mysis populations and their role in ecosystem structure and function. We summarise current knowledge of Mysis DVM and provide an expanded framework that more fully considers the role of benthic habitat. Acknowledging benthic habitat as an integral part of Mysis ecology will enable research to better understand the role of Mysis in food web processes.

Freshwater Biology↗

USGS2007

Sediment geochemical records of productivity and oxygen depletion along the margin of western North America during the past 60,000 years: Teleconnections with Greenland Ice and the Cariaco Basin

Many sediment records from the margins of the Californias (Alta and Baja) collected in water depths between 60 and 1200 m contain anoxic intervals (laminated sediments) that can be correlated with interstadial intervals as defined by the oxygen-isotope composition of Greenland ice (Dansgaard–Oeschger, D–O, cycles). These intervals include all or parts of Oxygen Isotope Stage 3 (OIS3; 60–24 cal ka), the Bölling/Alleröd warm interval (B/A; 15–13 cal ka), and the Holocene. This study uses organic carbon (Corg) and trace-element proxies for anoxia and productivity, namely elevated concentrations and accumulation rates of molybdenum and cadmium, in these laminated sediments to suggest that productivity may be more important than ventilation in producing changes in bottom-water oxygen (BWO) conditions on open, highly productive continental margins. The main conclusion from these proxies is that during the last glacial interval (LGI; 24–15 cal ka) and the Younger Dryas cold interval (YD; 13–11.6 cal ka) productivity was lower and BWO levels were higher than during OIS3, the B/A, and the Holocene on all margins of the Californias. The Corg and trace-element profiles in the LGI–B/A–Holocene transition in the Cariaco Basin on the margin of northern Venezuela are remarkably similar to those in the transition on the northern California margin. Correlation between D–O cycles in Greenland ice with gray-scale measurements in varved sediments in the Cariaco Basin also is well established. Synchronous climate-driven changes as recorded in the sediments on the margins of the Californias, sediments from the Cariaco Basin, and in the GISP-2 Greenland ice core support the hypothesis that changes in atmospheric dynamics played a major role in abrupt climate change during the last 60 ka. Millennial-scale cycles in productivity and oxygen depletion on the margins of the Californias demonstrate that the California Current System was poised at a threshold whereby perturbations of atmospheric circulation produced rapid changes in circulation in the eastern North Pacific Ocean. It is likely that the Pacific and Atlantic Oceans were linked through the atmosphere. Warmer air temperatures during interstadials would have strengthened Hadley and Walker circulations, which, in turn, would have strengthened the subtropical high pressure systems in both the North Pacific and the North Atlantic, producing increased rainfall over the Cariaco Basin and increased upwelling along the margins of the Californias.

California↗

USGS2011

Distribution and abundance of saltcedar and Russian olive in the western United States

Over the past century, two introduced Eurasian trees, saltcedar (Tamarix spp.) and Russian olive (Elaeagnus angustifolia) have become wide spread on western United States of American (U.S.) rivers. This paper reviews the literature on the following five key areas related to their distribution and abundance in the western United States: (1) the history of introduction, planting, and spread of saltcedar and Russian olive; (2) their current distribution; (3) their current abundance; (4) factors controlling their current distribution and abundance; and (5) models that have been developed to predict their future distribution and abundance. Saltcedar and Russian olive are now the third and fourth most frequently occurring woody riparian plants and the second and fifth most abundant species (out of 42 native and non-native species) along rivers in the western United States. Currently there is not a precise estimate of the areas that these species occupy in the entire West. Climatic variables are important determinants of their distribution and abundance. For example, saltcedar is limited by its sensitivity to hard freezes, whereas Russian olive appears to have a chilling requirement for bud break and seed germination, and can presumably survive colder winter temperatures. Either species can be dominant, co-dominant or sub-dominant relative to native species on a given river system. A number of environmental factors such as water availability, soil salinity, degree of stream flow regulation, and fire frequency can influence the abundance of these species relative to native species. Numerous studies suggest that both species have spread on western rivers primarily through a replacement process, whereby stress-tolerant species have moved into expanded niches that are no longer suitable for mesic native pioneer species. Better maps of current distribution and rigorous monitoring of distributional changes though time can help to resolve differences in predictions of potential future spread. An adequate understanding does not yet exist of what fraction of western riparian zones is resistant to dominance by either of these species, what fraction is at risk and could benefit from intervention, and what fraction has been altered to the point that saltcedar or Russian olive are most likely to thrive.

Critical Reviews in Plant Science↗

USGS1997

Characterization of the Martian surface deposits by the Mars Pathfinder rover, Sojourner

Sojourner, the Mars Pathfinder rover, discovered pebbles on the surface and in rocks that may be sedimentary—not volcanic—in origin. Surface pebbles may have been rounded by Ares flood waters or liberated by weathering of sedimentary rocks called conglomerates. Conglomerates imply that water existed elsewhere and earlier than the Ares flood. Most soil-like deposits are similar to moderately dense soils on Earth. Small amounts of dust are currently settling from the atmosphere.

Science↗

USGS2021

Dispersion and stratification dynamics in the upper Sacramento River deep water ship channel

Hydrodynamics control the movement of water and material within and among habitats, where time-scales of mixing can exert bottom-up regulatory effects on aquatic ecosystems through their influence on primary production. The San Francisco Estuary (estuary) is a low-productivity ecosystem, which is in part responsible for constraining higher trophic levels, including fishes. Many research and habitat-restoration efforts trying to increase primary production have been conducted, including, as described here, a whole-ecosystem nutrient addition experiment where calcium nitrate was applied in the Sacramento River Deep Water Ship Channel (DWSC) to see if phytoplankton production could be increased and exported out of the DWSC. As an integral part of this experiment, we investigated the physical mechanisms that control mixing, and how these mechanisms affect the strength and duration of thermal stratification, which we revealed as critical for controlling phytoplankton dynamics in the relatively turbid upper DWSC. Analysis of a suite of mixing mechanisms and time-scales show that both tidal currents and wind control mixing rates and stratification dynamics in the DWSC. Longitudinal and vertical dispersion increased during periods of high wind, during which wind speed influenced dispersion more than tidal currents. Thermal stratification developed most days, which slowed vertical mixing but was rapidly broken down by wind-induced mixing. Stratification rarely persisted for longer than 24 hours, limiting phytoplankton production in the study area. The interaction between physical mechanisms that control mixing rates, mediate stratification dynamics, and ultimately limit primary production in the DWSC may be useful in informing habitat restoration elsewhere in the Delta and in other turbid aquatic environments.

California↗

USGS2025

Application of a data-limited stock assessment model to understand the historical population of cisco in Lake Erie

Historically, cisco (Coregonus artedi) supported one of the largest commercial fisheries in Lake Erie with over 25 million kilograms landed in a single year during the fisheries’ peak in 1912. Like many other coregonines in the Laurentian Great Lakes, the Lake Erie cisco population eventually collapsed and is now considered extirpated. Management interest in restoring coregonine abundance and diversity across the Great Lakes motivated the development of a multi-agency, science-based framework aimed at restoring or enhancing populations. As part of that framework, we applied a data-limited model (depletion-based stock reduction analysis) to a reconstructed catch series to estimate historical levels of abundance of cisco in Lake Erie. Estimated historical carrying capacity was 171 million kilograms (66.5 kg/ha) and estimated annual exploitation was as high as 70 %. Model projections suggested the population should have rebuilt following a fishery collapse in 1925; however, the fishery remained depressed and cisco disappeared from Lake Erie despite the end of targeted exploitation in 1965. Other factors, such as habitat degradation and invasive species, are believed to have played a part in impeding recovery of cisco. The results of this study could be used in setting potential restoration targets for Lake Erie cisco given current conditions. The likelihood of achieving recovery targets based on historical population size will be dependent on the suitability of current conditions for sustaining the population.

Lake Erie↗

USGS2015

Geospatial resources for the geologic community: The USGS National Map

Geospatial data are a key component of investigating, interpreting, and communicating the geological sciences. Locating geospatial data can be time-consuming, which detracts from time spent on a study because these data are not obviously placed in central locations or are served from many disparate databases. The National Map of the US Geological Survey is a publicly available resource for accessing the geospatial base map data needs of the geological community from a central location. The National Map data are available through a viewer and download platform providing access to eight primary data themes, plus the US Topo and scanned historical topographic maps. The eight themes are elevation, orthoimagery, hydrography, geographic names, boundaries, transportation, structures, and land cover, and they are being offered for download as predefined tiles in formats supported by leading geographic information system software. Data tiles are periodically refreshed to capture the most current content and are an efficient method for disseminating and receiving geospatial information. Elevation data, for example, are offered as a download from the National Map as 1° × 1° tiles for the 10- and 30- m products and as 15′ × 15′ tiles for the higher-resolution 3-m product. Vector data sets with smaller file sizes are offered at several tile sizes and formats. Partial tiles are not a download option—any prestaged data that intersect the requesting bounding box will be, in their entirety, part of the download order. While there are many options for accessing geospatial data via the Web, the National Map represents authoritative sources of data that are documented and can be referenced for citation and inclusion in scientific publications. Therefore, National Map products and services should be part of a geologist’s first stop for geospatial information and data.

Journal of Geology↗