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Robin Stewart

Research Hydrologist

Contact Info

Short Biography

Robin Stewart has been a research hydrologist with U.S. Geological Survey's National Research Program (NRP) in Menlo Park since 2003.  She received an undergraduate degree in Biology from the University of Victoria, British Columbia Canada in 1991 and a PhD in ecotoxicology from the University of Manitoba in 1998. Immediately following this she pursued a postdoctoral appointment with Canada's Department of Fisheries and Oceans in 1998 evaluating the fate and transport of organic contaminants during the 1997 Red River Flood.  In the spring of 1999 she began her postdoctoral research with the USGS National Research Program. 

For the past twenty years Robin Stewart's research has focused on identifying and understanding processes influencing the fate and bioavailability of selenium (Se), mercury (Hg), and organic contaminants in food webs across a range of aquatic environments including estuaries (San Francisco Bay and Puget Sound), rivers (Manitoba/North Dakota, Oregon, Wisconsin and Florida), lakes (Manitoba and Ontario), and tidal rivers and reservoirs (California).  Through a combination of field-based process studies, in situ monitoring of key biomonitors over short-term (<3 years) and long-term (>10 years) time series, biodyanamic modeling and knowledge gained through laboratory-based studies of physiological uptake she strives to identify critical processes controlling contaminant bioaccumulation in nature.  


Zeug SC, Brodsky A, Kogut N, Stewart AR, Merz J (2014) Ancient fish and recent invaders: white sturgeon (Acipenser transmontanus) diet response to invasive species-mediated changes in a benthic prey assemblage. Mar Ecol Prog Ser 514:163-174 [Link]

Stewart AR, Luoma SN, Elrick KA, Carter JL, van der Wegen M (2013) Influence of Estuarine Processes on Spatiotemporal Variation in Bioavailable Selenium. Mar Ecol Prog Ser 492:41-56 [Link]

Huffman RL, Wagner RJ, Toft J, Cordell J, DeWild, JF, Dinicola RS, Aiken GR, Krabbenhoft DP, Marvin-DiPasquale M, Stewart AR, Moran PW, and Paulson AJ, 2012. Mercury species and other selected constituent concentrations in water, sediment, and biota of Sinclair Inlet, Kitsap County, Washington, 2007–10: U.S. Geological Survey Data Series 658, 64 p. [Link]

Selck H, Drouillard K, Eisenreich K, Koelmans AA, Palmqvist A, Ruus A, Salvito D, Schultz I, Stewart AR, Weisbrod A, van den Brink NW, van den Heuvel-Greve M (2011) Explaining differences between bioaccumulation measurements in laboratory and field data through use of a probabilistic modeling approach. Integr Environ Assess Manage 7:1-22 [Link]

Kleckner AE, Stewart AR, Elrick KA, Luoma SN (2010) Selenium concentrations and stable isotopic compositions of carbon and nitrogen in the benthic clam Corbula amurensis from Northern San Francisco Bay, California: May 1995–February 2010. U.S. Geological Survey Open-File Report 2010-1252, 34 p. [Link]

Stewart AR, Grosell M, Buchwalter DB, Fisher N, Luoma SN, Mathews T, Orr PL, Wang WX (2010) Bioaccumulation and trophic transfer of selenium. In: Chapman PM, Adams WJ, Brooks ML, Delos CG, Luoma SN, Maher WA, Ohlendorf HM, Presser T, Shaw DP (eds) Ecological Assessment of Selenium in the Aquatic Environment [Download File]

Chasar LC, Scudder BC, Stewart AR, Bell AH, Aiken GR (2009) Mercury cycling in stream ecosystems: 3. Trophic dynamics and methylmercury bioaccumulation. EnvironSciTechnol 43:2733-2739 [Link]

Grimaldo LF, Stewart AR, Kimmerer W (2009) Dietary segregation of pelagic and littoral fish assemblages in a highly modified tidal freshwater estuary. Marine and Coastal Fisheries: Dynamics, Managment, and Ecosystem Science 1:200-217 [Link]

Alpers CN, Stewart AR, Saiki MK, Marvin-DiPasquale M, Topping BR, Rider KM, Gallanthine SK, Kester CA, Rye RO, Antweiler RC, DeWild JF (2008) Environmental factors affecting mercury in Camp Far West Reservoir, 2001-03. U.S. Geological Survey Scientific Investigations Report 2006-5008, p. [Link]

Luoma SN, Anderson SA, Bergamaschi B, Holm L, Ruhl C, Schoellhamer DH, Stewart AR (2008) Water Quality. In: Healey MC, Dettinger MD, Norgaard RB (eds) The State of Bay-Delta Science, 2008. Calfed Science Program, 174 p. [Link]

Stewart AR, Saiki MK, Kuwabara JS, Alpers CN, Marvin-DiPasquale M, Krabbenhoft DP (2008) Influence of plankton mercury dynamics and trophic pathways on mercury concentrations of top predator fish of a mining-impacted reservoir. Can J Fish Aquat Sci 65:2351-2366 [Link]

Marvin-DiPasquale M, Stewart AR, Fisher N, Pickhardt PC, Mason RP, Heyes A, Windham-Myers L (2007) Evaluation of Mercury Transformations and Trophic Transfer in the San FranciscoBay/Delta: Identifying Critical Processes for the Ecosystem Restoration Program.

Croteau MN, Luoma SN, Stewart AR (2005) Trophic transfer of metals along freshwater food webs: Evidence of cadmium biomagnification in nature. Limnol Oceanogr 50:1511-1519

Lucas LV, Stewart AR (2005) Tranport, transformation, and effects of selenium and carbon in the delta of the Sacramento-San Joaquin Rivers: Implications for ecosystem restoration. 406 p. [Link]

Stewart AR, Luoma SN, Schlekat CE, Doblin MA, Hieb KA (2004) Food Web Pathway Determines How Selenium Affects Aquatic Ecosystems: A San Francisco Bay Case Study. Environ Sci Technol 38:4519-4526 [Link]

Kuwabara JS, Alpers CN, Marvin-DiPasquale M, Topping BR, Carter JL, Stewart AR, Fend SV, Parchaso F, Moon GE, Krabbenhoft DP (2003) Sediment-water interactions affecting dissolved-mercury distributions in Camp Far West Reservoir, California. Water Resources Investigation Report 03-4140 61 p. [Link]

Stewart AR, Stern GA, Lockhart WL, Kidd KA, Salki A, Stainton M, Koczanski K, Rosenberg DM, Savoie DA, Billeck BN, Wilkinson P, Muir DCG (2003) Assessing trends in organochlorine concentrations in Lake Winnipeg fish following the 1997 Red River flood. JGreat Lakes Res 29:332-354 [Link]

Baines SB, Fisher NS, Stewart AR (2002) Assimilation and retention of Se and other trace elements from crustacean food by juvenile striped bass (Morone saxatilis). Limnol Oceanogr 47:646-655 [Download File]

Stewart AR, Stern GA, Salki A, Stainton MP, Lockhart WL, Billeck BN, Danell R, Delaronde J, Grift NP, Halldorson T, Koczanski K, MacHutcheon A, Rosenberg GB, Savoie DA, Tenkula D, Tomy G, Yarchewski A (2000) Influence of the 1997 Red River flood on contaminant transport and fate in southern Lake Winnipeg. 1-42 p. [Download File]

Stewart AR (1999) Accumulation of Cd by a freshwater mussel (Pyganodon grandis) is reduced in the presence of Cu, Zn, Pb, and Ni. Can J Fish Aquat Sci 56:467-478 [Link]

Stewart AR, Malley DF (1999) Effect of metal mixture (Cu, Zn, Pb and Ni) on cadmium partitioning in littoral sediments and its accumulation by the freshwater macrophyte Eriocaulon septangulare Environ Toxicol Chem 18:436-447 [Link]

Malley DF, Stewart AR, Hall BD (1996) Uptake of methyl mercury by the floater mussel, Pyganodon grandis (Bivalvia, Unionidae), caged in a flooded wetland. Environ Toxicol Chem 15:928-936 [Link]


My Science Topics

Science Topic
Ecology and Environmentaquatic ecosystems
Ecology and Environmentecological processes
Water Resourcesestuaries
Water Resourceslakes
Water Resourcessurface water quality
Water Resourcesdroughts
Water Resourcesfloodplains

My USGS Science Strategy Areas

Understanding Ecosystems & Predicting Ecosystems Change

Climate Variability & Change

Bioavailability, bioaccumulation and trophic transfer of selenium and mercury in dynamic aquatic ecosystems

Dietary contaminants such as selenium (Se), mercury (Hg) and organic chemicals have the potential to threaten fish and birds, and impede ecosystem restoration efforts in rivers, lakes and estuaries worldwide. For example, Se contamination remains an ongoing issue for resource managers because it is a by-product of common economic activities including coal-fire generation of electricity, oil refining, agriculture, and mining of phosphate, copper and uranium.  Understanding the complexities of Se behavior in ecosystems is critical because of the potential for future changes in Se source loading, water management, hydroclimatic conditions and ecosystem restoration that could alter Se exposures in the food web, potentially exacerbating the problem. 

Research Links

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Contact Information

Robin Stewart
345 Middlefield Road
Menlo Park, CA 94025
650-329-4545 - Fax
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