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At least 955 records · Page 53Linked to original sources
USGS2014

Metal Mixture Modeling Evaluation project: 2. Comparison of four modeling approaches

As part of the Metal Mixture Modeling Evaluation (MMME) project, models were developed by the National Institute of Advanced Industrial Science and Technology (Japan), the U.S. Geological Survey (USA), HDR⎪HydroQual, Inc. (USA), and the Centre for Ecology and Hydrology (UK) to address the effects of metal mixtures on biological responses of aquatic organisms. A comparison of the 4 models, as they were presented at the MMME Workshop in Brussels, Belgium (May 2012), is provided herein. Overall, the models were found to be similar in structure (free ion activities computed by WHAM; specific or non-specific binding of metals/cations in or on the organism; specification of metal potency factors and/or toxicity response functions to relate metal accumulation to biological response). Major differences in modeling approaches are attributed to various modeling assumptions (e.g., single versus multiple types of binding site on the organism) and specific calibration strategies that affected the selection of model parameters. The models provided a reasonable description of additive (or nearly additive) toxicity for a number of individual toxicity test results. Less-than-additive toxicity was more difficult to describe with the available models. Because of limitations in the available datasets and the strong inter-relationships among the model parameters (log KM values, potency factors, toxicity response parameters), further evaluation of specific model assumptions and calibration strategies is needed.

Environmental Toxicology and Chemistry↗
USGS2026

Resilience thinking for human-wildlife coexistence: Bridging dynamic systems, archetypes, and transformations

As human activities and wildlife increasingly overlap in the Anthropocene, conventional conservation paradigms focused on land-sparing are shifting toward strategies that support human–wildlife coexistence. However, achieving sustainable coexistence is often hindered by a limited understanding of the dynamic social–ecological processes that drive integrated human–wildlife systems. This Special Issue explores “resilience thinking” as a scientific framework to address these knowledge gaps. By bridging sustainability and wildlife sciences, we examine how concepts such as adaptive capacity, feedback loops, system archetypes, and tipping points can illuminate the conditions that facilitate stable coexistence or lead to persistent conflict. Through diverse global case studies ranging from carnivore management in Europe to primate interactions in Indonesia, contributions highlight how societal perceptions, governance, and co-adaptation shape system trajectories. Ultimately, we argue that fostering durable coexistence requires moving beyond incremental adaptation toward transformative governance that centers on equity, relationality, and proactive management.

Ambio↗
USGS2012

Effects of activity and energy budget balancing algorithm on laboratory performance of a fish bioenergetics model

We evaluated the performance of the Wisconsin bioenergetics model for lake trout Salvelinus namaycush that were fed ad libitum in laboratory tanks under regimes of low activity and high activity. In addition, we compared model performance under two different model algorithms: (1) balancing the lake trout energy budget on day t based on lake trout energy density on day t and (2) balancing the lake trout energy budget on day t based on lake trout energy density on day t + 1. Results indicated that the model significantly underestimated consumption for both inactive and active lake trout when algorithm 1 was used and that the degree of underestimation was similar for the two activity levels. In contrast, model performance substantially improved when using algorithm 2, as no detectable bias was found in model predictions of consumption for inactive fish and only a slight degree of overestimation was detected for active fish. The energy budget was accurately balanced by using algorithm 2 but not by using algorithm 1. Based on the results of this study, we recommend the use of algorithm 2 to estimate food consumption by fish in the field. Our study results highlight the importance of accurately accounting for changes in fish energy density when balancing the energy budget; furthermore, these results have implications for the science of evaluating fish bioenergetics model performance and for more accurate estimation of food consumption by fish in the field when fish energy density undergoes relatively rapid changes.

Transactions of the American Fisheries Society↗
USGS2010

Ecological requirements for pallid sturgeon reproduction and recruitment in the Lower Missouri River: Annual report 2009

The Comprehensive Sturgeon Research Project is a multiyear, multiagency collaborative research framework developed to provide information to support pallid sturgeon recovery and Missouri River management decisions. The general Comprehensive Sturgeon Research Project strategy is to integrate field and laboratory studies of sturgeon reproductive ecology, habitat requirements, and physiology to produce a predictive understanding of sturgeon population dynamics. The project scope of work is developed annually with cooperating research partners and in collaboration with the U.S. Army Corps of Engineers, Missouri River Recovery-Integrated Science Program. The research consists of several interdependent and complementary research tasks engaging multiple disciplines that primarily address spawning as a probable limiting factor in reproduction and survival of the pallid sturgeon. The research is multifaceted and is designed to provide information needed for management decisions impacting habitat restoration, flow modification, and pallid sturgeon population augmentation on the Missouri River, and throughout the range of the species. Research activities and progress towards understanding of the species are reported to the U.S. Army Corps of Engineers annually. This annual report details the research effort and progress made by Comprehensive Sturgeon Research Project during 2009.

Open-File Report↗
USGS2022

Estimated daily mean streamflow in Iowa using the Flow-Duration Curve Transfer Method StreamStats application

The U.S. Geological Survey (USGS) operates many streamgages throughout the country that provide historical and real-time daily streamflow information. Accurate estimates of daily streamflow and the percentage of time that a certain volume of streamflow occurs or is exceeded in a stream is crucial information for structure design and other activities conducted by federal, state, and local officials. However, many important locations are ungaged and therefore lack the in-depth data provided at streamgages. The USGS provides hydrologic information like streamflow statistics and drainage basin characteristics in the web-based tool StreamStats (https://streamstats.usgs.gov/ss/). A newly released StreamStats functionality developed by the StreamStats development team working closely with USGS scientists in the Central Midwest Water Science Center incorporates flow-duration statistics already available at USGS streamgages to calculate daily mean streamflow estimates for rural, ungaged locations in Iowa [1].

Iowa↗
USGS2019

Canals, backfilling and wetland loss in the Mississippi Delta

Canals and spoil banks have contributed significantly to high rates of wetland loss in the Mississippi delta. There has been relatively little research on management of canals and spoil banks and this needs to be a significant component of restoration of the delta. We analyze research on the role of backfilling canals in the context of delta restoration with special reference to Turner and McClenachan (2018) who state that if all canals were backfilled, it could significantly reduce or even reverse wetland loss and that most wetland loss is caused by canals. We agree with T&M that canals have been a significant cause of wetland loss in the Mississippi Delta and that removing spoil banks and backfilling canals should be an integral part of delta restoration. However, a number of factors need to be considered when choosing which canals to backfill including possible enhanced erosion due to exposure to wave action for newly created and remnant marsh, the current and future production history of oil and natural gas from canals, and other restoration activities in oil and gas fields. Turner and McClenachan’s analysis using wetland loss patterns in 15-minute quadrangles suggesting that canal density can explain most wetland loss in coastal Louisiana is flawed because of scale problems and other impacts of oil and gas activity. These impacts include subsurface induced subsidence and the impact of produced water and toxins on wetlands that are largely unrelated to surface alteration due to canals and spoil banks.

Louisiana↗
USGS2019

Managing dams for energy and fish tradeoffs: What does a win-win solution take?

Management activities to restore endangered fish species, such as dam removals, fishway installations, and periodic turbine shutdowns, usually decrease hydropower generation capacities at dams. Quantitative analysis of the tradeoffs between energy production and fish population recovery related to dam decision-making is still lacking. In this study, an integrated hydropower generation and age-structured fish population model was developed using a system dynamics modeling method to assess basin-scale energy-fish tradeoffs under eight dam management scenarios. This model ran across 150 years on a daily time step, applied to five hydroelectric dams located in the main stem of the Penobscot River, Maine. We used alewife ( Alosa pseudoharengus ) to be representative of the local diadromous fish populations to link projected hydropower production with theoretical influences on migratory fish populations on the model river system. Our results show that while the five dams can produce around 427 GWh/year of energy, without fishway installations they would contribute to a 90% reduction in the alewife spawner abundance. The effectiveness of fishway installations is largely influenced by the size of reopened habitat areas and the actual passage rate of the fishways. Homing to natal habitat has an insignificant effect on the growth of the simulated spawner abundance. Operating turbine shutdowns during alewives' peak downstream migration periods, in addition to other dam management strategies, can effectively increase the spawner abundance by 480–550% while also preserving 65% of the hydropower generation capacity. These data demonstrate that in a river system where active hydropower dams operate, a combination of dam management strategies at the basin scale can best balance the tradeoff between energy production and the potential for migratory fish population recovery.

Maine↗
USGS2020

Endocrine disrupting activities and geochemistry of water resources associated with unconventional oil and gas activity

The rise of hydraulic fracturing and unconventional oil and gas (UOG) exploration in the United States has increased public concerns for water contamination induced from hydraulic fracturing fluids and associated wastewater spills. Herein, we collected surface and groundwater samples across Garfield County, Colorado, a drilling-dense region, and measured endocrine bioactivities, geochemical tracers of UOG wastewater, UOG-related organic contaminants in surface water, and evaluated UOG drilling production (weighted well scores, nearby well count, reported spills) surrounding sites. Elevated antagonist activities for the estrogen, androgen, progesterone, and glucocorticoid receptors were detected in surface water and associated with nearby shale gas well counts and density. The elevated endocrine activities were observed in surface water associated with medium and high UOG production (weighted UOG well score-based groups). These bioactivities were generally not associated with reported spills nearby, and often did not exhibit geochemical profiles associated with UOG wastewater from this region. Our results suggest the potential for releases of low-saline hydraulic fracturing fluids or chemicals used in other aspects of UOG production, similar to the chemistry of the local water, and dissimilar from defined spills of post-injection wastewater. Notably, water collected from certain medium and high UOG production sites exhibited bioactivities well above the levels known to impact the health of aquatic organisms, suggesting that further research to assess potential endocrine activities of UOG operations is warranted.

Science of the Total Environment↗
USGS2002

Accumulation rate and mixing of shelf sediments in the Monterey Bay National Marine Sanctuary

The distribution of excess 210Pb in 31 sediment cores was used to determine modern (last 100 yr) mass accumulation rates and the depth of sediment mixing on the continental shelf between Pacifica and Monterey, California, USA. Apparent mass accumulation rates average 0.27 g cm-2 yr-1 and range from 0.42 g cm-2 yr-1 to 0.12 g cm-2 yr-1. Accumulation rates were highest at mid-shelf water depths (60-100 m) adjacent to major rivers and near the head of the Ascension submarine canyon. Cores from water depths of less than 65 m had low, uniform 210Pb activity profiles and sandy textures. The uppermost 5-13 cm of 15 cores had uniform 210Pb activity profiles above a region of steadily decreasing 210Pb activity. This phenomenon was attributed to sediment mixing. The thickness of this upper layer of uniform 210Pb activity decreased southward from 13 cm, west of Pacifica, to less than 5 cm, near Monterey Canyon. This southward decrease may be attributed to shallower bioturbation in the southern study area. Integrated excess 210Pb activities were generally higher where sedimentation rates were high. They were also higher with increasing distance from major rivers. Thus, sedimentation rate alone does not explain the distribution of integrated excess 210Pb in this study area. Excess 210Pb in the seafloor is controlled by other factors such as sediment texture, the atmospheric deposition rate of 210Pb, and the residence time of sediment particles in the water column. ?? 2002 Elsevier Science B.V. All rights reserved.

Marine Geology↗
USGS2011

Interdisciplinary environmental project probes Chesapeake Bay down to the core

Interrelated environmental concerns about Chesapeake Bay are being addressed in an interdisciplinary project using paleoecological and geochemical records from sediment cores to investigate Holocene climate and human encroachment. The research is looking at interannual through millennial-scale variability of bay salinity, sediment accumulation, and dissolved oxygen, temperature, and faunal and floral trends. Current and planned research is expected to result in better restoration strategies by improving our understanding of the linkages between the bay's ecosystem, climate, and land use. Chesapeake Bay, the United States' largest and most productive estuary, faces several complex environmental issues, including eutrophication and anoxia in the main channel and tributaries, high turbidity and rates of sedimentation, outbreaks of the toxic dinoflagellate Pfiesteria piscicida , and coastal erosion and submergence tied to sea-level rise. Such problems often are attributed to human activities in the bay's watershed, including pollution, urbanization, and deforestation, but it now is recognized that climatic factors also strongly influence bay salinity, temperature, and water quality.

Chesapeake Bay watershed↗
USGS2025

Applying U.S. Geological Survey science to understand effects to water supply in the Upper Colorado River Basin

Introduction The Colorado River Basin is a vital source of water to more than 40 million people in the Western United States and Mexico, including in major cities like Denver, Las Vegas, Phoenix, Tucson, Los Angeles, and San Diego, and supports irrigation for about 16,000 square kilometers of agricultural land. Since 2000, the southwestern United States has been unusually dry due to low precipitation and warm air temperatures, contributing to extreme water level declines of the two large reservoirs on the Colorado River, Lake Mead and Lake Powell. In 2021, these reservoirs reached their lowest levels on record, resulting in unprecedented restrictions on water usage in the basin. As much as 90 percent of the annual runoff in the Colorado River Basin originates in areas upstream from Lake Powell (hereafter, these areas will be referred to collectively as the “Upper Basin”). Consequently, understanding the processes that can affect water supply in the Upper Basin could be crucial for supporting human, agricultural, and ecological needs across a large spatial scale. The U.S. Geological Survey (USGS) does a wide variety of science in cooperation with resource managers, municipalities, tribes, and local, State, and Federal agencies to help improve understanding of processes, such as streamflow and water quality, potentially affecting water supply in the Upper Basin. This fact sheet describes three key potential factors affecting water supply in the Upper Basin—snow processes and water storage, wildfire and basin hydrology, and salinity concentrations and water quality—and highlights associated USGS research activities in the basin.

Arizona, Colorado, New Mexico, Utah, Wyoming↗
USGS2019

Refining the Baseline Sediment Budget for the Klamath River, California

Four dams in the Klamath River Hydroelectric Project (KHP) in Oregon and California (Figure 1) are currently scheduled to be removed over a period of a few weeks or months, beginning in January 2021. The Klamath dam removal will be the largest in the world by almost all measures, and is an unprecedented opportunity to advance science of river responses to such events. The KHP contains approximately 10-12 million cubic meters of mostly fine sediment and model estimates suggest approximately 1/3-2/3 of this volume is expected to be eroded from reservoirs. Much of this sediment is expected to be eventually transported by the river to, or through, the Klamath River Estuary, a distance of more than 300 kilometers. To improve the success of restoration activities following dam removal, agencies must understand the baseline conditions for biological, chemical, and physical processes, prior to the removal. We expect large changes in water quality (turbidity, suspended sediment, dissolved oxygen, temperature, and algal toxins) and in fish habitat in the Hydroelectric Reach and the main-stem of the Klamath River to the ocean. For example, modeled sediment concentrations in the Klamath River during dam removal were estimated exceed 10,000 – 15,000 mg/L, depending on streamflows, location, and the dam removal process, and to remain > 100 – 1000 mg/L for months at a time. Final time to achieve background concentrations post dam removal may take over two years (Reclamation, 2011). Plans to assess many of these changes post-dam removal are still being formulated.

California, Oregon↗
USGS2016

Smokey comes of age: Unmanned aerial systems for fire management

During the past century, fire management has focused on techniques both to protect human communities from catastrophic wildfire and to maintain fire-dependent ecological systems. However, despite a large and increasing allocation of resources and personnel to achieve these goals, fire management objectives at regional to global scales are not being met. Current fire management techniques are clearly inadequate for the challenges faced by fire managers, and technological innovations are needed. Advances in unmanned aerial systems (UAS) technology provide opportunities for innovation in fire management and science. In many countries, fire management organizations are beginning to explore the potential of UAS for monitoring fires. We have taken the next step and developed a prototype that can precisely ignite fires as part of wildfire suppression tactics or prescribed fires (fire intentionally ignited within predetermined conditions to reduce hazardous fuels, improve habitat, or mitigate for large wildfires). We discuss the potential for these technologies to benefit fire management activities, while acknowledging the sizeable sociopolitical barriers that prevent their immediate broad application.

Frontiers in Ecology and the Environment↗
USGS2000

Chronology and geochemistry of late Holocene eolian deposits in the Brandon Sand Hills, Manitoba, Canada

Accelerator mass spectrometry and conventional radiocarbon age determinations of organic matter from paleosols indicate that the Brandon Sand Hills area of southern Manitoba has been subjected to recurrent intervals of eolian activity in the past 5000 years. Although precise regional correlations are precluded by dating uncertainties, periods of most notable paleosol development occurred around 2300 to 2000, 1400 to 1000, and 600 to 500 cal yr BP with eolian activity occurring before and after each of these periods. Episodes of eolian activity may correspond to periods of regional drought, whereas paleosols mark periods of increased moisture availability and stabilization by vegetation. The geochemistry of the eolian sands, paleosols and source sediments indicates that partial leaching of carbonates occurs from pedogenesis during humid climatic phases, and that this is probably the primary mechanism of carbonate depletion of eolian sands in this area. Recent trends in sand dune activity from historic aerial photography and early explorers' accounts indicate that the few active dunes that presently exist have stabilized at a rate of 10-20% per decade, despite several severe droughts in the 20th century. This may be attributed to pre-settlement droughts that were more severe than those in historic times although regional dune stabilization may also be related, in part, to the spread of forest cover in the past few hundred years. Crown copyright (C) 2000 Published by Elsevier Science Ltd. All rights reserved.

Quaternary International↗
USGS2012

Reducing Vulnerability of Ports and Harbors to Earthquake and Tsunami Hazards

Recent scientific research suggests the Pacific Northwest could experience catastrophic earthquakes in the near future, both from distant and local sources, posing a significant threat to coastal communities. Damage could result from numerous earthquake-related hazards, such as severe ground shaking, soil liquefaction, landslides, land subsidence/uplift, and tsunami inundation. Because of their geographic location, ports and harbors are especially vulnerable to these hazards. Ports and harbors, however, are important components of many coastal communities, supporting numerous activities critical to the local and regional economy and possibly serving as vital post-event, response-recovery transportation links. A collaborative, multi-year initiative is underway to increase the resiliency of Pacific Northwest ports and harbors to earthquake and tsunami hazards, involving Oregon Sea Grant (OSG), Washington Sea Grant (WSG), the National Oceanic and Atmospheric Administration Coastal Services Center (CSC), and the U.S. Geological Survey Center for Science Policy (CSP). Specific products of this research, planning, and outreach initiative include a regional stakeholder issues and needs assessment, a community-based mitigation planning process, a Geographic Information System (GIS) — based vulnerability assessment methodology, an educational web-site and a regional data archive. This paper summarizes these efforts, including results of two pilot port-harbor community projects, one in Yaquina Bay, Oregon and the other in Sinclair Inlet, Washington. Finally, plans are outlined for outreach to other port and harbor communities in the Pacific Northwest and beyond, using "getting started" workshops and a web-based tutorial.

Oregon, Washington↗
USGS2013

Field calibration and validation of remote-sensing surveys

The Optical Collection Suite (OCS) is a ground-truth sampling system designed to perform in situ measurements that help calibrate and validate optical remote-sensing and swath-sonar surveys for mapping and monitoring coastal ecosystems and ocean planning. The OCS system enables researchers to collect underwater imagery with real-time feedback, measure the spectral response, and quantify the water clarity with simple and relatively inexpensive instruments that can be hand-deployed from a small vessel. This article reviews the design and performance of the system, based on operational and logistical considerations, as well as the data requirements to support a number of coastal science and management projects. The OCS system has been operational since 2009 and has been used in several ground-truth missions that overlapped with airborne lidar bathymetry (ALB), hyperspectral imagery (HSI), and swath-sonar bathymetric surveys in the Gulf of Maine, southwest Alaska, and the US Virgin Islands (USVI). Research projects that have used the system include a comparison of backscatter intensity derived from acoustic (multibeam/interferometric sonars) versus active optical (ALB) sensors, ALB bottom detection, and seafloor characterization using HSI and ALB.

Alaska↗
USGS2016

Tearing the terroir: Details and implications of surface rupture and deformation from the 24 August 2014 M6.0 South Napa earthquake, California

The M w 6.0 South Napa earthquake of 24 August 2014 caused slip on several active fault strands within the West Napa Fault Zone (WNFZ). Field mapping identified 12.5 km of surface rupture. These field observations, near-field geodesy and space geodesy, together provide evidence for more than ~30 km of surface deformation with a relatively complex distribution across a number of subparallel lineaments. Along a ~7 km section north of the epicenter, the surface rupture is confined to a single trace that cuts alluvial deposits, reoccupying a low-slope scarp. The rupture continued northward onto at least four other traces through subparallel ridges and valleys. Postseismic slip exceeded coseismic slip along much of the southern part of the main rupture trace with total slip 1 year postevent approaching 0.5 m at locations where only a few centimeters were measured the day of the earthquake. Analysis of airborne interferometric synthetic aperture radar data provides slip distributions along fault traces, indicates connectivity and extent of secondary traces, and confirms that postseismic slip only occurred on the main trace of the fault, perhaps indicating secondary structures ruptured as coseismic triggered slip. Previous mapping identified the WNFZ as a zone of distributed faulting, and this was generally borne out by the complex 2014 rupture pattern. Implications for hazard analysis in similar settings include the need to consider the possibility of complex surface rupture in areas of complex topography, especially where multiple potentially Quaternary-active fault strands can be mapped.

California↗
USGS2009

Co-seismic ruptures of the 12 May 2008, M s 8.0 Wenchuan earthquake, Sichuan: East-west crustal shortening on oblique, parallel thrusts along the eastern edge of Tibet

The M s 8.0, Wenchuan earthquake, which devastated the mountainous western rim of the Sichuan basin in central China, produced a surface rupture over 200??km-long with oblique thrust/dextral slip and maximum scarp heights of ~ 10??m. It thus ranks as one of the world's largest continental mega-thrust events in the last 150??yrs. Field investigation shows clear surface breaks along two of the main branches of the NE-trending Longmen Shan thrust fault system. The principal rupture, on the NW-dipping Beichuan fault, displays nearly equal amounts of thrust and right-lateral slip. Basin-ward of this rupture, another continuous surface break is observed for over 70??km on the parallel, more shallowly NW-dipping Pengguan fault. Slip on this latter fault was pure thrusting, with a maximum scarp height of ~ 3.5??m. This is one of the very few reported instances of crustal-scale co-seismic slip partitioning on parallel thrusts. This out-of-sequence event, with distributed surface breaks on crustal mega-thrusts, highlights regional, ~ EW-directed, present day crustal shortening oblique to the Longmen Shan margin of Tibet. The long rupture and large offsets with strong horizontal shortening that characterize the Wenchuan earthquake herald a re-evaluation of tectonic models anticipating little or no active shortening of the upper crust along this edge of the plateau, and require a re-assessment of seismic hazard along potentially under-rated active faults across the densely populated western Sichuan basin and mountains. ?? 2009 Elsevier B.V.

Earth and Planetary Science Letters↗