Sarah E Janssen
Sarah Janssen is an isotope geochemist working in the M3 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
Fox River walleye mercury isotope data Fox River walleye mercury isotope data
Adult walleye were caught in Fox River (Wisconsin) during April 2014. Age-0 walleye were caught in Fox River during October 2014. Total length, weight, age, and proportion of weight represented by water were determined for each of the walleye. Whole-fish homogenates were prepared during 2014-2015 and during 2017. Total mercury (HgT) concentration, methylmercury (MeHg) concentration, and...
Data for Biogeochemical and Physical Processes Controlling Mercury and Selenium Bioaccumulation in Bighorn Lake, Bighorn Canyon National Recreation Area, Montana and Wyoming, 2015-2016 Data for Biogeochemical and Physical Processes Controlling Mercury and Selenium Bioaccumulation in Bighorn Lake, Bighorn Canyon National Recreation Area, Montana and Wyoming, 2015-2016
This dataset includes the field measurements and laboratory analyses of surface water, seston, fish tissue, and sediment samples collected from Bighorn Lake, within Bighorn Canyon National Recreation area (BICA), during high flow (July 2015) and low flow (August 2016) conditions. The study area includes 7-9 sampling sites that follow a transect spanning the entire length of the reservoir...
Filter Total Items: 50
Isotope fractionation from In Vivo methylmercury detoxification in waterbirds Isotope fractionation from In Vivo methylmercury detoxification in waterbirds
The robust application of stable mercury (Hg) isotopes for mercury source apportionment and risk assessment necessitates the understanding of mass-dependent fractionation (MDF) due to internal transformations within organisms. Here, we used high energy-resolution XANES spectroscopy and isotope ratios of total mercury (δ202THg) and methylmercury (δ202MeHg) to elucidate the chemical...
Authors
Brett Poulin, Sarah Elizabeth Janssen, Tylor Rosera, David P. Krabbenhoft, Collin A. Eagles-Smith, Josh T. Ackerman, Robin Stewart, Eunhee Kim, Zofia Baumann, Jeong-Hoon Kim, Alain Manceau
Examining historical mercury sources in the Saint Louis River estuary: How legacy contamination influences biological mercury levels in Great Lakes coastal regions Examining historical mercury sources in the Saint Louis River estuary: How legacy contamination influences biological mercury levels in Great Lakes coastal regions
Industrial chemical contamination within coastal regions of the Great Lakes can pose serious risks to wetland habitat and offshore fisheries, often resulting in fish consumption advisories that directly affect human and wildlife health. Mercury (Hg) is a contaminant of concern in many of these highly urbanized and industrialized coastal regions, one of which is the Saint Louis River...
Authors
Sarah E. Janssen, Joel C. Hoffman, Ryan F. Lepak, David P. Krabbenhoft, David M. Walters, Collin A. Eagles-Smith, Greg Peterson, Jacob M. Ogorek, John F. DeWild, Anne M Cotter, Mark Pearson, Michael T. Tate, Roger B. Yeardley, Marc A. Mills
The influence of legacy contamination on the transport and bioaccumulation of mercury within the Mobile River Basin The influence of legacy contamination on the transport and bioaccumulation of mercury within the Mobile River Basin
Past industrial use and subsequent release of mercury (Hg) into the environment have resulted in severe cases of legacy contamination that still influence contemporary Hg levels in biota. While the bioaccumulation of legacy Hg is commonly assessed via concentration measurements within fish tissue, this practice becomes difficult in regions of high productivity and methylmercury (MeHg)...
Authors
Sarah E. Janssen, Michael T. Tate, David P. Krabbenhoft, John F. DeWild, Jacob M. Ogorek, Christopher L. Babiarz, Anthony Sowers, Peter L. Tuttle
Insights into mercury source identification and bioaccumulation using stable isotope approaches in the Hannibal Pool of the Ohio River Insights into mercury source identification and bioaccumulation using stable isotope approaches in the Hannibal Pool of the Ohio River
Mercury contamination in river systems due to historic and current Hg releases is a persistent concern for both wildlife and human health. In larger rivers, like the Ohio River, USA, it is difficult to directly link Hg discharges to bioaccumulation due to the existence of multiple industrial Hg sources as well as the varied dietary and migratory habits of biota. To better understand how...
Authors
Sarah E. Janssen, Kathleen A. Patnode, Bruce R Pluta, David P. Krabbenhoft
Tracing the uptake of Hg(II) in an iron-reducing bacterium using mercury stable isotopes Tracing the uptake of Hg(II) in an iron-reducing bacterium using mercury stable isotopes
Anaerobic microorganisms play a key role in the biological mercury (Hg) cycle due to their ability to produce bioaccumulative neurotoxic methylmercury (MeHg). However, despite recent advances, how bacteria accumulate inorganic Hg [Hg(II)] prior to methylation is largely unknown. In this study, we applied Hg stable isotopes to measure changes in cellular compartments of Geobacter...
Authors
Yuwei Wang, Sarah E. Janssen, Jeffra K Schaefer, Nathan Yee, John R Reinfelder
Mercury, cadmium, copper, arsenic, and selenium measurements in the feathers of adult eastern brown pelicans (Pelecanus occidentalis carolinensis) and chicks in multiple breeding grounds in the northern Gulf of Mexico Mercury, cadmium, copper, arsenic, and selenium measurements in the feathers of adult eastern brown pelicans (Pelecanus occidentalis carolinensis) and chicks in multiple breeding grounds in the northern Gulf of Mexico
The amounts of trace metals and metalloids that have been introduced into aquatic ecosystems due to anthropogenic activities have increased in recent decades. Some of these elements like mercury are easily transferred from one trophic level to another and can accumulate to toxic quantities in organisms at the top of aquatic food webs. For this reason, seabirds like the Eastern brown...
Authors
U. Ndu, J. S. Lamb, Sarah E. Janssen, R. Rossi, Y. G. Satgé, Patrick G.R. Jodice
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
Fox River walleye mercury isotope data Fox River walleye mercury isotope data
Adult walleye were caught in Fox River (Wisconsin) during April 2014. Age-0 walleye were caught in Fox River during October 2014. Total length, weight, age, and proportion of weight represented by water were determined for each of the walleye. Whole-fish homogenates were prepared during 2014-2015 and during 2017. Total mercury (HgT) concentration, methylmercury (MeHg) concentration, and...
Data for Biogeochemical and Physical Processes Controlling Mercury and Selenium Bioaccumulation in Bighorn Lake, Bighorn Canyon National Recreation Area, Montana and Wyoming, 2015-2016 Data for Biogeochemical and Physical Processes Controlling Mercury and Selenium Bioaccumulation in Bighorn Lake, Bighorn Canyon National Recreation Area, Montana and Wyoming, 2015-2016
This dataset includes the field measurements and laboratory analyses of surface water, seston, fish tissue, and sediment samples collected from Bighorn Lake, within Bighorn Canyon National Recreation area (BICA), during high flow (July 2015) and low flow (August 2016) conditions. The study area includes 7-9 sampling sites that follow a transect spanning the entire length of the reservoir...
Filter Total Items: 50
Isotope fractionation from In Vivo methylmercury detoxification in waterbirds Isotope fractionation from In Vivo methylmercury detoxification in waterbirds
The robust application of stable mercury (Hg) isotopes for mercury source apportionment and risk assessment necessitates the understanding of mass-dependent fractionation (MDF) due to internal transformations within organisms. Here, we used high energy-resolution XANES spectroscopy and isotope ratios of total mercury (δ202THg) and methylmercury (δ202MeHg) to elucidate the chemical...
Authors
Brett Poulin, Sarah Elizabeth Janssen, Tylor Rosera, David P. Krabbenhoft, Collin A. Eagles-Smith, Josh T. Ackerman, Robin Stewart, Eunhee Kim, Zofia Baumann, Jeong-Hoon Kim, Alain Manceau
Examining historical mercury sources in the Saint Louis River estuary: How legacy contamination influences biological mercury levels in Great Lakes coastal regions Examining historical mercury sources in the Saint Louis River estuary: How legacy contamination influences biological mercury levels in Great Lakes coastal regions
Industrial chemical contamination within coastal regions of the Great Lakes can pose serious risks to wetland habitat and offshore fisheries, often resulting in fish consumption advisories that directly affect human and wildlife health. Mercury (Hg) is a contaminant of concern in many of these highly urbanized and industrialized coastal regions, one of which is the Saint Louis River...
Authors
Sarah E. Janssen, Joel C. Hoffman, Ryan F. Lepak, David P. Krabbenhoft, David M. Walters, Collin A. Eagles-Smith, Greg Peterson, Jacob M. Ogorek, John F. DeWild, Anne M Cotter, Mark Pearson, Michael T. Tate, Roger B. Yeardley, Marc A. Mills
The influence of legacy contamination on the transport and bioaccumulation of mercury within the Mobile River Basin The influence of legacy contamination on the transport and bioaccumulation of mercury within the Mobile River Basin
Past industrial use and subsequent release of mercury (Hg) into the environment have resulted in severe cases of legacy contamination that still influence contemporary Hg levels in biota. While the bioaccumulation of legacy Hg is commonly assessed via concentration measurements within fish tissue, this practice becomes difficult in regions of high productivity and methylmercury (MeHg)...
Authors
Sarah E. Janssen, Michael T. Tate, David P. Krabbenhoft, John F. DeWild, Jacob M. Ogorek, Christopher L. Babiarz, Anthony Sowers, Peter L. Tuttle
Insights into mercury source identification and bioaccumulation using stable isotope approaches in the Hannibal Pool of the Ohio River Insights into mercury source identification and bioaccumulation using stable isotope approaches in the Hannibal Pool of the Ohio River
Mercury contamination in river systems due to historic and current Hg releases is a persistent concern for both wildlife and human health. In larger rivers, like the Ohio River, USA, it is difficult to directly link Hg discharges to bioaccumulation due to the existence of multiple industrial Hg sources as well as the varied dietary and migratory habits of biota. To better understand how...
Authors
Sarah E. Janssen, Kathleen A. Patnode, Bruce R Pluta, David P. Krabbenhoft
Tracing the uptake of Hg(II) in an iron-reducing bacterium using mercury stable isotopes Tracing the uptake of Hg(II) in an iron-reducing bacterium using mercury stable isotopes
Anaerobic microorganisms play a key role in the biological mercury (Hg) cycle due to their ability to produce bioaccumulative neurotoxic methylmercury (MeHg). However, despite recent advances, how bacteria accumulate inorganic Hg [Hg(II)] prior to methylation is largely unknown. In this study, we applied Hg stable isotopes to measure changes in cellular compartments of Geobacter...
Authors
Yuwei Wang, Sarah E. Janssen, Jeffra K Schaefer, Nathan Yee, John R Reinfelder
Mercury, cadmium, copper, arsenic, and selenium measurements in the feathers of adult eastern brown pelicans (Pelecanus occidentalis carolinensis) and chicks in multiple breeding grounds in the northern Gulf of Mexico Mercury, cadmium, copper, arsenic, and selenium measurements in the feathers of adult eastern brown pelicans (Pelecanus occidentalis carolinensis) and chicks in multiple breeding grounds in the northern Gulf of Mexico
The amounts of trace metals and metalloids that have been introduced into aquatic ecosystems due to anthropogenic activities have increased in recent decades. Some of these elements like mercury are easily transferred from one trophic level to another and can accumulate to toxic quantities in organisms at the top of aquatic food webs. For this reason, seabirds like the Eastern brown...
Authors
U. Ndu, J. S. Lamb, Sarah E. Janssen, R. Rossi, Y. G. Satgé, Patrick G.R. Jodice
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.