Sarah E Janssen
Sarah Janssen is an isotope geochemist working in the Mercury Research Lab (MRL) located within the Upper Midwest Water Science Center.
She has a PhD in environmental chemistry from Rutgers University and a bachelor’s in chemistry from
University of the Sciences in Philadelphia. Her work focuses on the application of stable isotope techniques for understanding sources and transformations of mercury (Hg) in the environment. Her research interests include Hg cycling in contaminated ecosystems, the investigation of microbial Hg transformations using stable isotopes, and development of analytical methods to improve Hg isotope measurements.
Current Projects
- Mercury Cycling and Source Identification in the St Louis River Estuary MN/WI (collaboration with US EPA and Minnesota Pollution Control Agency)
- Mercury Isotope Fractionation during Microbial Uptake and Transformations of Hg (collaboration with Rutgers University and University of Ottawa)
- Method Development for the Pre-concentration of Waters and Low Concentration Environmental Samples for Mercury Isotopic Analysis
Education and Certifications
Ph.D. 2016, Environmental Chemistry, Rutgers University, New Brunswick, NJ
B.S. 2011, Chemistry, University of the Sciences, Philadelphia, PA
Science and Products
Filter Total Items: 38
Mercury Methylation Assay Along a Salinity Gradient in Coastal Peat Soils in the Florida Everglades
This data was collected as part of a laboratory study examining the effects of sea level rise on mercury (Hg) methylation and demethylation rates in peat cores collected from the Florida Everglades. Peat cores were collected from a freshwater region of the Everglades, Water Conservation Area 3, in 2022 and taken to the University of California-Davis for methylation and demethylation...
Mercury in soil, water, sediment, and biota in headwater streams associated with wildfires in the northwestern U.S., 2021-2022
Comma-separated values (.csv) files containing data related to mercury in soil, water, sediment, in-stream leaf litter, periphyton, and aquatic invertebrates collected in 2021-2022 from headwater streams associated with wildfires in the northwestern U.S.
Mercury Stable Isotope Assessment of Dragonflies and Fish Tissues across United States National Parks
This dataset details mercury (Hg) stable isotope values in dragonflies and fish tissues collected across U.S. National Parks. Dragonfly samples were collected as part of the Dragonfly Mercury Project (https://geonarrative.usgs.gov/dmp/), a citizen science project focused on using dragonfly larvae as biosentinels for Hg bioaccumulation. Fish were collected as part of separate park-wide...
Walleye (Sander vitreus), Yellow Perch (Perca flavescens) and Surface Water Mercury Concentrations in Minnesota Lakes
Water quality and fish tissue samples were collected and measured for mercury concentrations in a total of 23 small to medium size lakes in Minnesota to assess the impact that zebra mussel (Dreissena polymorpha) invasion had on mercury bioaccumulation. Water samples were collected in October and November of 2021 from 22 lakes and analyzed for total mercury, methylmercury, dissolved...
Great Lakes Sediment Surveillance Program: Mercury Concentrations and Mercury Stable Isotopes in Sediments of the Laurentian Great Lakes
As part of the larger Great Lakes Sediment Surveillance Program (GLSSP), the U.S. Geological Survey Mercury Research Laboratory (MRL) partnered with the U.S. Environmental Protection Agency and the University of Minnesota-Duluth to assess contaminant concentrations within surface sediments and sediment cores from the Laurentian Great Lakes. Sediments were assessed for mercury...
Measurements of mercury stable isotopes during planktonic uptake and photochemical demethylation of methylmercury
Laboratory experiments were performed between 2019 and 2020 to examine how dissolved organic matter (DOM) and phytoplankton (Raphidocelis subcapitata) cells alter mercury (Hg) uptake and isotope fractionation. Experiments were performed at ambient Hg to thiol ratios using natural organic matter isolates received from collaborators at the University of California-Davis. Two types of...
Filter Total Items: 43
Adaptable plasmonic membrane sensors for fast and reliable detection of trace low micrometer microplastics in lake water
In freshwater environments, low-micrometer microplastics (LMMPs) have captured significant attention due to their prevalence and toxicity. Yet, rapid detection of LMMPs (1–10 μm) at the single-particle level within complex freshwater matrices remains a hurdle. We developed an adaptable plasmonic membrane sensor for fast detection of individual LMMPs in eutrophic lake waters. The...
Authors
Ziyan Wu, Sarah Elizabeth Janssen, Michael Tate, Hoaran Wei, Mohan Qin
Mesopelagic diet as pathway of high mercury levels in body feathers of the endangered Black-capped Petrel (Diablotin) Pterodroma hasitata
The Diablotin or Black-capped Petrel Pterodroma hasitata is an endangered gadfly petrel found in the western North Atlantic, Caribbean Sea, and northern Gulf of Mexico. An estimated ~2000 pairs nest at five known sites on Hispaniola, Greater Antilles, although only 120 nests have been located to date. We collected breast feathers and feces from breeding adults in the Dominican Republic...
Authors
Yvan G. Satgé, Sarah Elizabeth Janssen, Gemma Clucas, Ernst Rupp, J. Brian Patteson, Patrick G.R. Jodice
Hair mercury isotopes, a noninvasive biomarker for dietary methylmercury exposure and biological uptake
Background. Fish and rice are the main dietary sources of methylmercury (MeHg); however, rice does not contain the same beneficial nutrients as fish, and these differences can impact the observed health effects of MeHg. Hence, it is important to validate a biomarker, which can distinguish among dietary MeHg sources. Methods. Mercury (Hg) stable isotopes were analyzed in hair samples from...
Authors
Sarah E Rothenburg, Susan A Korrick, Donald Harrington, Sally W Thurston, Sarah Elizabeth Janssen, Michael Tate, YanFen Nong, Hua Nong, Jihong Liu, Chuan Hong, Fengxiu Ouyang
Simulated sea level rise in coastal peat oils stimulates mercury methylation
Coastal wetlands are vulnerable to sea level rise with unknown consequences for mercury (Hg) cycling, particularly the potential for exacerbating neurotoxic methylmercury (MeHg) production and bioaccumulation in food webs. Here, the effect of sea level rise on MeHg formation in the Florida Everglades was evaluated by incubating peat cores from a freshwater wetland for 0–20 days in the...
Authors
Bryce A. Cook, Benjamin D. Peterson, Jacob M. Ogorek, Sarah Elizabeth Janssen, Brett Poulin
Wildfires influence mercury transport, methylation, and bioaccumulation in headwater streams of the Pacific Northwest
The increasing frequency and severity of wildfires are among the most visible impacts of climate change. However, the effects of wildfires on mercury (Hg) transformations and bioaccumulation in stream ecosystems are poorly understood. We sampled soils, water, sediment, in-stream leaf litter, periphyton, and aquatic invertebrates in 36 burned (one-year post fire) and 21 reference...
Authors
Austin K. Baldwin, James Willacker, Branden L. Johnson, Sarah Elizabeth Janssen, Collin Eagles-Smith
Connecting tributary mercury loads to nearshore and offshore sediments in Lake Superior
Lake Superior has a vast and largely undeveloped watershed in comparison to the other Great Lakes, which makes it challenging to study mercury (Hg) sources and cycling. To examine Hg inputs to Lake Superior, we conducted an expansive binational assessment in 40 watersheds from a diverse range of landcover types. We further paired tributary Hg data to sediment source portfolios in the...
Authors
Sarah Elizabeth Janssen, Michael Tate, Eric D. Dantoin, Christopher T. Filstrup, Euan D. Reavie, Robert M Stewart, Chris Robinson, Craig J Allan, Dale M. Robertson, David Krabbenhoft
Non-USGS Publications**
Janssen, S.E.; Johnson, M.W.; Blum, J.D.; Barkay, T.; Reinfelder, J.R., Separation of monomethylmercury from estuarine sediments for mercury isotope analysis. Chemical Geology 2015
Janssen, S.E.; Schaefer, J.K.; Barkay, T.; Reinfelder, J.R. Fractionation of mercury stable isotopes during microbial methylmercury production in pure culture. Environ. Sci. Technol. 2016
Lloyd, N.; Janssen, S.E.; Reinfelder J.R.; Barkay, T., Exposure to mercury selects for antibiotic resistance in Fundulus heteroclitus gut microbiome, Current Microbiology, 2016
**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
Filter Total Items: 38
Mercury Methylation Assay Along a Salinity Gradient in Coastal Peat Soils in the Florida Everglades
This data was collected as part of a laboratory study examining the effects of sea level rise on mercury (Hg) methylation and demethylation rates in peat cores collected from the Florida Everglades. Peat cores were collected from a freshwater region of the Everglades, Water Conservation Area 3, in 2022 and taken to the University of California-Davis for methylation and demethylation...
Mercury in soil, water, sediment, and biota in headwater streams associated with wildfires in the northwestern U.S., 2021-2022
Comma-separated values (.csv) files containing data related to mercury in soil, water, sediment, in-stream leaf litter, periphyton, and aquatic invertebrates collected in 2021-2022 from headwater streams associated with wildfires in the northwestern U.S.
Mercury Stable Isotope Assessment of Dragonflies and Fish Tissues across United States National Parks
This dataset details mercury (Hg) stable isotope values in dragonflies and fish tissues collected across U.S. National Parks. Dragonfly samples were collected as part of the Dragonfly Mercury Project (https://geonarrative.usgs.gov/dmp/), a citizen science project focused on using dragonfly larvae as biosentinels for Hg bioaccumulation. Fish were collected as part of separate park-wide...
Walleye (Sander vitreus), Yellow Perch (Perca flavescens) and Surface Water Mercury Concentrations in Minnesota Lakes
Water quality and fish tissue samples were collected and measured for mercury concentrations in a total of 23 small to medium size lakes in Minnesota to assess the impact that zebra mussel (Dreissena polymorpha) invasion had on mercury bioaccumulation. Water samples were collected in October and November of 2021 from 22 lakes and analyzed for total mercury, methylmercury, dissolved...
Great Lakes Sediment Surveillance Program: Mercury Concentrations and Mercury Stable Isotopes in Sediments of the Laurentian Great Lakes
As part of the larger Great Lakes Sediment Surveillance Program (GLSSP), the U.S. Geological Survey Mercury Research Laboratory (MRL) partnered with the U.S. Environmental Protection Agency and the University of Minnesota-Duluth to assess contaminant concentrations within surface sediments and sediment cores from the Laurentian Great Lakes. Sediments were assessed for mercury...
Measurements of mercury stable isotopes during planktonic uptake and photochemical demethylation of methylmercury
Laboratory experiments were performed between 2019 and 2020 to examine how dissolved organic matter (DOM) and phytoplankton (Raphidocelis subcapitata) cells alter mercury (Hg) uptake and isotope fractionation. Experiments were performed at ambient Hg to thiol ratios using natural organic matter isolates received from collaborators at the University of California-Davis. Two types of...
Filter Total Items: 43
Adaptable plasmonic membrane sensors for fast and reliable detection of trace low micrometer microplastics in lake water
In freshwater environments, low-micrometer microplastics (LMMPs) have captured significant attention due to their prevalence and toxicity. Yet, rapid detection of LMMPs (1–10 μm) at the single-particle level within complex freshwater matrices remains a hurdle. We developed an adaptable plasmonic membrane sensor for fast detection of individual LMMPs in eutrophic lake waters. The...
Authors
Ziyan Wu, Sarah Elizabeth Janssen, Michael Tate, Hoaran Wei, Mohan Qin
Mesopelagic diet as pathway of high mercury levels in body feathers of the endangered Black-capped Petrel (Diablotin) Pterodroma hasitata
The Diablotin or Black-capped Petrel Pterodroma hasitata is an endangered gadfly petrel found in the western North Atlantic, Caribbean Sea, and northern Gulf of Mexico. An estimated ~2000 pairs nest at five known sites on Hispaniola, Greater Antilles, although only 120 nests have been located to date. We collected breast feathers and feces from breeding adults in the Dominican Republic...
Authors
Yvan G. Satgé, Sarah Elizabeth Janssen, Gemma Clucas, Ernst Rupp, J. Brian Patteson, Patrick G.R. Jodice
Hair mercury isotopes, a noninvasive biomarker for dietary methylmercury exposure and biological uptake
Background. Fish and rice are the main dietary sources of methylmercury (MeHg); however, rice does not contain the same beneficial nutrients as fish, and these differences can impact the observed health effects of MeHg. Hence, it is important to validate a biomarker, which can distinguish among dietary MeHg sources. Methods. Mercury (Hg) stable isotopes were analyzed in hair samples from...
Authors
Sarah E Rothenburg, Susan A Korrick, Donald Harrington, Sally W Thurston, Sarah Elizabeth Janssen, Michael Tate, YanFen Nong, Hua Nong, Jihong Liu, Chuan Hong, Fengxiu Ouyang
Simulated sea level rise in coastal peat oils stimulates mercury methylation
Coastal wetlands are vulnerable to sea level rise with unknown consequences for mercury (Hg) cycling, particularly the potential for exacerbating neurotoxic methylmercury (MeHg) production and bioaccumulation in food webs. Here, the effect of sea level rise on MeHg formation in the Florida Everglades was evaluated by incubating peat cores from a freshwater wetland for 0–20 days in the...
Authors
Bryce A. Cook, Benjamin D. Peterson, Jacob M. Ogorek, Sarah Elizabeth Janssen, Brett Poulin
Wildfires influence mercury transport, methylation, and bioaccumulation in headwater streams of the Pacific Northwest
The increasing frequency and severity of wildfires are among the most visible impacts of climate change. However, the effects of wildfires on mercury (Hg) transformations and bioaccumulation in stream ecosystems are poorly understood. We sampled soils, water, sediment, in-stream leaf litter, periphyton, and aquatic invertebrates in 36 burned (one-year post fire) and 21 reference...
Authors
Austin K. Baldwin, James Willacker, Branden L. Johnson, Sarah Elizabeth Janssen, Collin Eagles-Smith
Connecting tributary mercury loads to nearshore and offshore sediments in Lake Superior
Lake Superior has a vast and largely undeveloped watershed in comparison to the other Great Lakes, which makes it challenging to study mercury (Hg) sources and cycling. To examine Hg inputs to Lake Superior, we conducted an expansive binational assessment in 40 watersheds from a diverse range of landcover types. We further paired tributary Hg data to sediment source portfolios in the...
Authors
Sarah Elizabeth Janssen, Michael Tate, Eric D. Dantoin, Christopher T. Filstrup, Euan D. Reavie, Robert M Stewart, Chris Robinson, Craig J Allan, Dale M. Robertson, David Krabbenhoft
Non-USGS Publications**
Janssen, S.E.; Johnson, M.W.; Blum, J.D.; Barkay, T.; Reinfelder, J.R., Separation of monomethylmercury from estuarine sediments for mercury isotope analysis. Chemical Geology 2015
Janssen, S.E.; Schaefer, J.K.; Barkay, T.; Reinfelder, J.R. Fractionation of mercury stable isotopes during microbial methylmercury production in pure culture. Environ. Sci. Technol. 2016
Lloyd, N.; Janssen, S.E.; Reinfelder J.R.; Barkay, T., Exposure to mercury selects for antibiotic resistance in Fundulus heteroclitus gut microbiome, Current Microbiology, 2016
**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.