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The goal of my biodegradation research is to understand the processes controlling the rate of biodegradation of contaminants in the subsurface. This understanding will form the basis of methods to increase degradation rates without causing further degradation of groundwater quality. Recent work has focused on the fate of crude oil and agricultural nitrate contamination in the subsurface. Specific objectives for the crude oil research include: (a) determine the rate that contaminants are transported from the source zone; (b) provide an estimate of how long the spilled oil will continue to pollute the groundwater; and (c) determine the fate of products of biodegradation or so-called “secondary water quality impacts”...
To study the mechanisms, pathways, and rates of transformation of carbon and nitrogen compounds (natural and contaminant) mediated by microorganisms in aquatic habitats and identify factors controlling these transformations and to examine the effect that these transformations have upon other biogeochemical processes.
The purpose of my research group is to develop new methods and applications of environmental isotopes to solve problems of national importance. In specific, the overall goal is to use environmental isotopes, combined with other biogeochemical measurements and hydrologic and biogeochemical modeling, to increase our understanding of biogeochemical and hydrological processes, nutrient and organic matter sources, subsurface flowpaths, and water age distributions in diverse environments. Many of our studies piggyback on the sampling efforts of major monitoring programs to investigate causes of hypoxia and food web problems. Our work provides critical scientific support for these monitoring programs. A long-term career...
Evaluate the hydrologic and geochemical processes that control nitrate fluxes in agricultural settings. Important questions remain about the overall regional and global importance of groundwater nitrogen fluxes, denitrification (microbial reduction of NO 3 − to N 2), and the sources of electron donors contributing to this microbial reaction. Studies are needed that apply robust methods for measuring nitrogen fluxes and denitrification among multiple sites to evaluate important factors affecting N fluxes. These results, in combination with novel methods for efficient estimation of fluxes in groundwater, facilitate estimates of N fluxes in across large regions such as the Corn Belt. Quantify the effects of complex...
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Southern Nevada Water Authority will add new modeling and analytical capabilities to tools developed as part of a previous WaterSMART Climate Analysis Tools Grant that assessed impacts of climate change on water quality and sediment transport in Lake Mead. Project results are intended to increase an understanding of how water quality characteristics and nutrient levels in Lake Mead may be affected by climate change.
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Problem The discharge of freshwater and associated loading of nutrients and other dissolved constituents from the Long Island aquifer system to surrounding estuaries and their tributaries are increasingly recognized as critical factors in the health of these ecosystems. However, further work is needed to scientifically characterize these factors and present them to the public in an appropriate manner. Many organizations have undertaken assessments of this discharge and loading for discrete groundwater source areas and (or) receiving surface waters, applying a variety of techniques and assumptions. In part, this is because there is no delineation of recharge areas to the island’s groundwater-fed streams and estuaries...
Categories: Data, Project; Types: Downloadable, Map Service, OGC WFS Layer, OGC WMS Layer, Shapefile; Tags: Basin & Hydrogeologic Characterization, Basin & Hydrogeologic Characterization, Climate Change, Climate Research and Development, ClimateChange, All tags...
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Description of Work Participation on the Lake Erie Lakewide Management Plan Workgroup and related subcommittees such as toxics, sources and loads, nutrients, and biodiversity. Attend meetings and conferences associated with LE LAMP activities. This includes The Lake Erie Millennium Network, CSMI, Ohio Phosphorus Task Force, and other meetings or workshops addressing nutrient and toxicity issues in Lake Erie. Communicate USGS activities in the Lake Erie Basin that can influence understanding or impact decision making.
Improve understanding of physical and biogeochemical processes affecting water quality of groundwater and surface water. Research focus includes multidisciplinary field and laboratory studies to determine factors affecting sources, movement, and fate of nutrients and reactive inorganic contaminants in the hydrologic cycle. Improve the usefulness of stable isotopes and other environmental tracers in hydrology and biogeochemistry by developing new techniques and approaches. Research topics include analytical techniques for stable isotopes in compounds separated from groundwater and surface water, stable isotope forensics, enriched isotope tracer experiments to quantify transport and reaction rates, field and...
The objectives are to 1) Quantify the hydrogeomorphic and ecological controls of nutrient and contaminant fluxes in wetland ecosystems; 2) Scale wetland fluxes from site to watershed scale; and 3) Identify the principals and modeling tools for managing wetland and river ecosystems. The focus will be on floodplain ecosystems, which are poorly studied due to the challenges of working in this environment and their inherent complexity.
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This project, a collaborative study involving the U.S. Geological Survey (USGS) and Heidelberg University, focuses on using multi-agency water monitoring data in the Lake Erie basin (fig. 1) and a USGS package of software tools (dataRetrieval and EGRET; Hirsch and De Cicco, 2015 ) to evaluate seasonal and annual phosphorus and nitrogen trends, and to relate observed trends to climate, streamflow, and land-use activities. EGRET utilizes a recently developed trend method, Weighted Regressions on Time, Discharge, and Season (WRTDS; Hirsch and others, 2010 ). WRTDS is designed to remove the effects of year-to-year streamflow variations on nutrient trends and provide improvements over prior conventional trend methods,...
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Description of Work U.S. Geological Survey (USGS) scientists collect real-time, near-real-time, and synoptic flow and water-quality data (sediment and nutrients) from tributaries to the Great Lakes. The data provide baseline information to assess effectiveness of restoration and land management activities. Thirty of the 59 major downstream flow gages are continuously operating for water-quality samplings at these sites (number of sites reduced to 25 effective June 30, 2013). The work builds on current USGS monitoring efforts and those of partners in the Great Lakes. The results of this effort will provide information on nutrient and sediment loads and measure the effectiveness of restoration efforts in selected...
Natural water systems provide a wide range of conditions within which to examine the geochemical behavior and cycling of trace elements and nutrients relative to hydrochemically important mineral reactions. Processes of mineral dissolution, alteration and genesis exert strong controls on the concentrations of chemical species in natural water systems and thus on water quality. Chemical composition of atmospheric precipitation input to terrestrial watersheds affects mineral reaction rates and may regulate reaction pathways and products. Knowledge of the geochemical behavior and cycles of major elements, trace elements, and nutrients is essential in order to understand and predict the consequences of deliberate or...
The tundra biome is the dominant terrestrial ecosystem of the circumpolar north, and its fate in a rapidly changing climate is of high scientific and socioeconomic concern. One of those concerns is that the majority of caribou herds throughout the circumpolar north are declining, perhaps as a result of climate change. The principal objective of this research is to reveal the connections between soil nutrient cycling, forage quality and caribou habitat selection. This framework is underpinned by the concept that tundra ecosystem productivity is ultimately driven by the thermodynamics of the system induced by climate. In winter, soil microbial processes drive N mineralization and thus N available for plant growth...
The objectives of my work are to better understand nutrient sources and cycling in specific environments to aid in resource management and pollution abatement and to improve and develop isotopic analytical methodologies.
I study biogeochemical cycling in aquatic ecosystems. Current projects include 1) Trends in alkalinity and acidity in coastal rivers of the US and potential effects on coastal acidification (USGS NAWQA Trends Team). 2) Continental-scale synthesis of stream metabolism and its links to water quality and the aquatic carbon cycle (USGS Powell Center; USGS NAWQA; USGS NRP). 3) Carbon transport and cycling in the Upper Mississippi River basin (USGS LandCarbon). 4) Long-term trends in acidification of the Delaware River Estuary (Penn State University). 5) Hyporheic exchange in contrasting headwater streams of the Colorado Front Range (with Colorado School of Mines).
The overall objective of this project is to determine the role of chemical processes associated with dissolved organic carbon (DOC) on the transport and reactivity of both naturally occurring and anthropogenic compounds. Defining the roles of DOC in environmental and geochemical processes is critical to understanding the nature and quality of the Nation’s water resources, and is important for future management of these resources. This field of study has increased in relevancy as numerous environmental problems have been linked to processes involving organic matter. My project attempts to meet these needs by focusing on the chemical mechanisms controlling the fate, transport, and reactivity of naturally occurring...
The goal of our research is to understand how climate and land use change will alter soil function including nutrient, carbon and water cycling.
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The purpose of this workshop is to identify important hydro- and ecological relationships that will affect the ability of floodplain managers to optimize their approaches to providing: 1) fish habitat; 2) wildlife habitat; 3) nutrient and sediment processing; and 4) flood regulation. The resulting conceptual model will guide future floodplain science, including the development of numerical simulation models of high interest relationships. Twenty participants at the workshop included science experts on each of the four floodplain functions, policy analysts, and floodplain managers faced with making optimization decisions. The workshop report will focus on relationships of greatest need of quantification and how they...
map background search result map search result map A Study of Climate Change Impacts on Water Quality and Internal Nutrient Recycling in Lake Mead, Arizona-Nevada Lakewide Management Plan Capacity Support by U.S. Geological Survey - LAKE ERIE Lakewide Management Plan Capacity Support by U.S. Geological Survey - LAKE HURON Forecast/Nowcast Great Lakes Nutrient and Sediment Loadings Floodplain Functions Conceptual Modeling Workshop, West Alton, July 2014 Comprehensive Delineation of Groundwater Source Areas and Times-of-travel to Long Island Streams and Estuaries Evaluation of stream nutrient trends in the Lake Erie drainage basin in the presence of changing patterns in climate, streamflow, land drainage, and agricultural practices A Study of Climate Change Impacts on Water Quality and Internal Nutrient Recycling in Lake Mead, Arizona-Nevada Comprehensive Delineation of Groundwater Source Areas and Times-of-travel to Long Island Streams and Estuaries Lakewide Management Plan Capacity Support by U.S. Geological Survey - LAKE ERIE Evaluation of stream nutrient trends in the Lake Erie drainage basin in the presence of changing patterns in climate, streamflow, land drainage, and agricultural practices Lakewide Management Plan Capacity Support by U.S. Geological Survey - LAKE HURON Forecast/Nowcast Great Lakes Nutrient and Sediment Loadings Floodplain Functions Conceptual Modeling Workshop, West Alton, July 2014