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Sarah Stackpoole

Sarah Stackpoole is a Research Ecologist for the USGS Water Resources Mission Area.

I am a Research Ecologist with the US Geological Survey in Denver. I completed my undergraduate studies at the University of Michigan-Ann Arbor, my graduate studies at the University of Wisconsin-Madison, and I joined the USGS in 2009. I use field studies along with large-scale data assimilation and statistical approaches to document surface water quality status and trends. I also use a variety of methods to integrate water quality metrics with climate and land-use datasets to identify drivers of change in surface water quality and potential stessors on human and aquatic ecosystem health.  

Current and Past Projects:

  • USGS Harmful Algal Blooms Proxies Team (2020 - Present)
  • USGS Integrated Water Assessments Trends and Driver Team (2020 - Present) - Integrated Water Availability Assessments (IWAAs) (usgs.gov)
  • USGS National Water Quality Program Surface Water Status and Trends Team (2018 - 2021) - Document the impact of current and past anthropogenic phosphorus sources on soil saturation and water quality. Characterize the occurrence and distribution of pesticides in surface waters. https://water.usgs.gov/nawqa/swtrends/
  • USGS LandCarbon Team (2009 - 2017) - Assimilate large-scale datasets and determine the best statistical models and extrapolation methods to provide an assessment of current rates of freshwater carbon storage, transport, and emissions for the conterminous United States and Alaska. LandCarbon (usgs.gov)

 

Science and Products

Nutrient balances, river loads, and a counterfactual analysis to determine drivers of Mississippi River nitrogen and phosphorus loads between 1975 and 2017

This data release includes data processing scripts, data products, and associated metadata for a study investigating trends in Mississippi River (MR) nitrogen and phosphorus loads to the Gulf of Mexico. This data release consists of three main components: 1) Nitrogen and phosphorus balances, which account for major nutrient inputs (fertilizer, manure, waste water treatment facility effluent, atmos

Surface Water Pesticide Detection Frequency and Benchmark Exceedance Data for the Conterminous United States, 2013-2017

This product consists of pesticide detections and benchmark exceedances in surface waters. These are time series data representing water years 2013 - 2017 for river sites associated with the U.S. Geological Survey National Water Quality Pesticide Monitoring Program.
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Water Resources

Pesticide Toxicity Index (PTI) and maximum Toxic Unit (TUmax) scores and information for fish, cladocerans, and benthic invertebrates from water samples collected at National Water Quality Network sites during Water Years 2013-2017

During 2013-2017, the U.S. Geological Survey, National Water-Quality Assessment (NAWQA) Project, collected water samples year-round from the National Water Quality Network - Rivers and Streams (NWQN) and reported on 221 pesticides at 72 sites across the US in agricultural, developed, and mixed land use watersheds. Pesticide Toxicity Index (PTI) scores, a screening-level tool that uses an additive,
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Ohio-Kentucky-Indiana Water Science Center

Water quality, quantity, and gas fluxes of the Upper Mississippi River basin (WY 2012-2016)

This product consists of one tabular dataset and associated metadata of water quality information related to rivers, streams, and reservoirs in the Upper Mississippi River watershed between 2012 and 2016. This data release is a part of a national assessment of freshwater aquatic carbon fluxes. Data consist of organic and inorganic carbon related species, carbon dioxide and methane gas fluxes calcu
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Water Resources
Filter Total Items: 19

Long-term Mississippi River trends expose shifts in the river load response to watershed nutrient balances between 1975 and 2017

Excess nutrients transported by the Mississippi River (MR) contribute to hypoxia in the Gulf of Mexico. Nutrient balances are key drivers to river nutrient loads and represent inputs (fertilizer, manure, deposition, wastewater, N-fixation, and weathering) minus outputs (nutrient uptake and removal in harvest, and N emissions). Here, we quantified annual changes in nitrogen (N) and phosphorus (P) r
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Water Resources

Pesticides in US Rivers: Regional differences in use, occurrence, and environmental toxicity, 2013 to 2017

Pesticides pose a threat to the environment, but because of the substantial number of compounds, a comprehensive assessment of pesticides and an evaluation of the risk that they pose to human and aquatic life is challenging. In this study, improved analytical methods were used to quantify 221 pesticide concentrations in surface waters over the time period from 2013 to 2017. Samples were collected
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Water Resources

Pesticide mixtures show potential toxicity to aquatic life in U.S. streams, water years 2013-2017

During water years (WY) 2013–2017, the U.S. Geological Survey, National Water-Quality Assessment (NAWQA) Project, sampled the National Water Quality Network – Rivers and Streams (NWQN) year-round and reported on 221 pesticides at 72 sites across the United States in agricultural, developed, and mixed land use watersheds. The Pesticide Toxicity Index (PTI) was used to estimate the potential chronic
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National Water Quality Program, Caribbean-Florida Water Science Center (CFWSC), Ohio-Kentucky-Indiana Water Science Center

Variable impacts of contemporary versus legacy agricultural phosphorus on US river water quality

Phosphorus (P) fertilizer has contributed to the eutrophication of freshwater ecosystems. Watershed-based conservation programs aiming to reduce external P loading to surface waters have not resulted in significant water-quality improvements. One factor that can help explain the lack of water-quality response is remobilization of accumulated legacy (historical) P within the terrestrial-aquatic con
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Water Resources

Inland waters

1. The total flux of carbon—which includes gaseous emissions, lateral flux, and burial—from inland waters across the conterminous United States (CONUS) and Alaska is 193 teragrams of carbon (Tg C) per year. The dominant pathway for carbon movement out of inland waters is the emission of carbon dioxide gas across water surfaces of streams, rivers, and lakes (110.1 Tg C per year), a flux not identif

Assessing historical and projected carbon balance of Alaska: A synthesis of results and policy/management implications

We summarize the results of a recent interagency assessment of land carbon dynamics in Alaska, in which carbon dynamics were estimated for all major terrestrial and aquatic ecosystems for the historical period (1950–2009) and a projection period (2010–2099). Between 1950 and 2009, upland and wetland (i.e., terrestrial) ecosystems of the state gained 0.4 Tg C/yr (0.1% of net primary production, NPP
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Cooperative Research Units

Inland waters and their role in the carbon cycle of Alaska

The magnitude of Alaska (AK) inland waters carbon (C) fluxes is likely to change in the future due to amplified climate warming impacts on the hydrology and biogeochemical processes in high latitude regions. Although current estimates of major aquatic C fluxes represent an essential baseline against which future change can be compared, a comprehensive assessment for AK has not yet been completed.

Carbonate buffering and metabolic controls on carbon dioxide in rivers

Multiple processes support the significant efflux of carbon dioxide (CO2) from rivers and streams. Attribution of CO2 oversaturation will lead to better quantification of the freshwater carbon cycle and provide insights into the net cycling of nutrients and pollutants. CO2 production is closely related to O2consumption because of the metabolic linkage of these gases. However, this relationship can

Spatial and temporal patterns of dissolved organic matter quantity and quality in the Mississippi River Basin, 1997–2013

Recent studies have found insignificant or decreasing trends in time-series dissolved organic carbon (DOC) datasets, questioning the assumption that long-term DOC concentrations in surface waters are increasing in response to anthropogenic forcing, including climate change, land use, and atmospheric acid deposition. We used the weighted regressions on time, discharge, and season (WRTDS) model to e
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John Wesley Powell Center for Analysis and Synthesis

Aquatic carbon cycling in the conterminous United States and implications for terrestrial carbon accounting

Inland water ecosystems dynamically process, transport, and sequester carbon. However, the transport of carbon through aquatic environments has not been quantitatively integrated in the context of terrestrial ecosystems. Here, we present the first integrated assessment, to our knowledge, of freshwater carbon fluxes for the conterminous United States, where 106 (range: 71–149) teragrams of carbon p

Organic carbon burial in lakes and reservoirs of the conterminous United States

Organic carbon (OC) burial in lacustrine sediments represents an important sink in the global carbon cycle; however, large-scale OC burial rates are poorly constrained, primarily because of the sparseness of available data sets. Here we present an analysis of OC burial rates in water bodies of the conterminous U.S. (CONUS) that takes advantage of recently developed national-scale data sets on rese
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Water Resources, Ecosystems, Climate Research and Development Program, Land Change Science Program, Toxic Substances Hydrology, Environmental Health Program, Colorado Water Science Center

The river as a chemostat: fresh perspectives on dissolved organic matter flowing down the river continuum

A better understanding is needed of how hydrological and biogeochemical processes control dissolved organic carbon (DOC) concentrations and dissolved organic matter (DOM) composition from headwaters downstream to large rivers. We examined a large DOM dataset from the National Water Information System of the US Geological Survey, which represents approximately 100 000 measurements of DOC concentrat
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Water Resources, New York Water Science Center, California Water Science Center, John Wesley Powell Center for Analysis and Synthesis

Pre-USGS Publications

Stackpoole, S. M.; Kosola, K. R.; Workmaster, B. A. A.; Guldan, N. M.; Browne, B. A.; Jackson, R. D. , 2011. Looking beyond fertilizer: Assessing the contribution of nitrogen from hydrologic inputs and organic matter to plant growth in the cranberry agroecosystem , Nutrient Cycling in Agroecosystems 90:41-54.
Stackpoole, S., B. Workmaster, R. Jackson, K. Kosola. 2008. Nitrogen conservation strategies of cranberry plants and ericoid mycorrhizal fungi in an agroecosystem. Soil Biology & Biochemistry 40: 2736-2742
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Potential toxicity of pesticides to aquatic life in U.S. rivers is widespread

A new USGS study of pesticides in U.S. rivers and streams reports that, on average, 17 pesticides were detected at least once at the 74 river and...

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Phosphorus and River Water Quality

Investigating the effects of historical phosphorus on current river water quality. 

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Managing phosphorus in U.S. streams and rivers still a challenge

Despite decades of efforts to reduce phosphorus loads in streams, phosphorus continues to be a problem in many U.S. streams and rivers, causing...

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Science and Products