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
Harmonized discrete and continuous water quality data in support of modeling harmful algal blooms in the Illinois River Basin, 2005 - 2020
Harmful algal blooms (HABs) are overgrowths of algae or cyanobacteria in water and can be harmful to humans and animals directly via toxin exposure or indirectly via changes in water quality and related impacts to ecosystems services, drinking water characteristics, and recreation. While HABs occur frequently throughout the United States, the driving conditions behind them are not well understood,
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.
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,
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
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
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
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
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
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
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
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
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
Non-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
**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.
Science and Products
- Data
Harmonized discrete and continuous water quality data in support of modeling harmful algal blooms in the Illinois River Basin, 2005 - 2020
Harmful algal blooms (HABs) are overgrowths of algae or cyanobacteria in water and can be harmful to humans and animals directly via toxin exposure or indirectly via changes in water quality and related impacts to ecosystems services, drinking water characteristics, and recreation. While HABs occur frequently throughout the United States, the driving conditions behind them are not well understood,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, atmosSurface 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.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,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 - Publications
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) rPesticides 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 collectedPesticide 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 chronicVariable 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 conInland 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 identifAssessing 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, NPPInland 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 canSpatial 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 eAquatic 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 pOrganic 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 reseThe 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 concentratNon-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**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.
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