Brett A Poulin, PhD (Former Employee)
Science and Products
Shingobee Headwaters Aquatic Ecosystems Project (SHAEP)
The Shingobee Headwaters Aquatic Ecosystems Project (SHAEP) brings together scientists from the USGS along with students and professors from universities in Minnesota, North Dakota, Wisconsin, and California for a unique study opportunity. This diverse group of scientists research the physical, chemical, and biological processes of lakes, wetlands, and streams at local and watershed scales....
Beavers Impacting Tundra Ecosystems (BITE)
The range expansion of the North American beaver (Castor canadensis) has implications for water quality, aquatic ecosystems, and fisheries in Arctic streams.
Observed and modeled mercury and dissolved organic carbon concentrations and loads at control structure S-12D, Florida Everglades, 2013–17
Mercury (Hg) has been a contaminant of concern for several decades in South Florida, particularly in the Florida Everglades. The transport and bioavailability of Hg in aquatic systems is intimately linked to dissolved organic carbon (DOC). In aquatic systems, Hg can be converted to methylmercury (MeHg), which is the form of Hg that bioaccumulates...
Booth, Amanda; Poulin, Brett A.; Krabbenhoft, David P.Seasonal dynamics and interannual variability in mercury concentrations and loads through a three-reservoir complex
The Hells Canyon Complex (HCC) along the Snake River (Idaho-Oregon border, USA) encompasses three successive reservoirs that seasonally stratify, creating anoxic conditions in the hypolimnion that promote methylmercury (MeHg) production. This study quantified seasonal dynamics and interannual variability in mercury concentrations (inorganic...
Baldwin, Austin K.; Poulin, Brett; Naymik, Jesse; Hoovestol, Charles; Clark, Gregory M.; Krabbenhoft, David P.Permafrost hydrology drives the assimilation of old carbon by stream food webs in the Arctic
Permafrost thaw in the Arctic is mobilizing old carbon (C) from soils to aquatic ecosystems and the atmosphere. Little is known, however, about the assimilation of old C by aquatic food webs in Arctic watersheds. Here, we used C isotopes (δ13C, Δ14C) to quantify C assimilation by biota across 12 streams in arctic Alaska. Streams spanned watersheds...
O'Donnell, Jonathon A; Carey, Michael P.; Koch, Joshua C.; Xu, Xiaomei; Poulin, Brett; Walker, Jennifer; Zimmerman, Christian E.Aquatic cycling of mercury
This chapter examines crucial processes in the aquatic cycling of mercury (Hg) that may lead to microbial production of neurotoxic and bioaccumulative methylmercury (MeHg), and highlights environmental conditions in the Everglades that make it ideal for MeHg production and bioaccumulation. The role of complexation of Hg2+ in surface water,...
Orem, William H.; Krabbenhoft, David P.; Poulin, Brett; Aiken, George ASulfur contamination in the Everglades, a major control on mercury methylation
In this chapter sulfur contamination of the Everglades and its role as a major control on methylmercury (MeHg) production is examined. Sulfate concentrations over large portions of the Everglades (60% of the ecosystem) are elevated or greatly elevated compared to background conditions of <1 mg/L. Land and water management practices in...
Orem, William H.; Krabbenhoft, David P.; Poulin, Brett; George AikenGeochemical factors controlling dissolved elemental mercury and methylmercury formation in Alaskan wetlands of varying trophic status
Transformations of aqueous inorganic divalent mercury (Hg(II)i) to volatile dissolved gaseous mercury (Hg(0)(aq)) and toxic methylmercury (MeHg) governs mercury bioavailability and fate in northern ecosystems. This study quantified concentrations of aqueous mercury species (Hg(II)i, Hg(0)(aq), MeHg) and relevant geochemical constituents in pore...
Poulin, Brett; Ryan, Joseph N.; Tate, Michael; Krabbenhoft, David; Hines, Mark E; Barkay, Tamar; Schaefer, Jeffra; Aiken, George R.Effects of sulfide concentration and dissolved organic matter characteristics on the structure of nanocolloidal metacinnabar
Understanding the speciation of divalent mercury (Hg(II)) in aquatic systems containing dissolved organic matter (DOM) and sulfide is necessary to predict the conversion of Hg(II) to bioavailable methylmercury. We used X-ray absorption spectroscopy to characterize the structural order of mercury in Hg(II)–DOM–sulfide systems for a range of sulfide...
Poulin, Brett; Gerbig, Chase A.; Kim, Christopher S.; Stegemeier, John P.; Ryan, Joseph N.; Aiken, George R.Spatial dependence of reduced sulfur in Everglades dissolved organic matter controlled by sulfate enrichment
Sulfate inputs to the Florida Everglades stimulate sulfidic conditions in freshwater wetland sediments that affect ecological and biogeochemical processes. An unexplored implication of sulfate enrichment is alteration of the content and speciation of sulfur in dissolved organic matter (DOM), which influences the reactivity of DOM with trace metals...
Poulin, Brett A.; Ryan, Joseph N.; Nagy, Kathryn L.; Stubbins, Aron; Dittmar, Thorsten; Orem, William H.; Krabbenhoft, David P.; Aiken, George R.Mercury transformation and release differs with depth and time in a contaminated riparian soil during simulated flooding
Riparian soils are an important environment in the transport of mercury in rivers and wetlands, but the biogeochemical factors controlling mercury dynamics under transient redox conditions in these soils are not well understood. Mercury release and transformations in the Oa and underlying A horizons of a contaminated riparian soil were...
Poulin, Brett; Aiken, George R.; Nagy, Kathryn L.; Manceau, Alain; Krabbenhoft, David P.; Ryan, Joseph N.Formation of mercury sulfide from Hg(II)−thiolate complexes in natural organic matter
Methylmercury is the environmental form of neurotoxic mercury that is biomagnified in the food chain. Methylation rates are reduced when the metal is sequestered in crystalline mercury sulfides or bound to thiol groups in macromolecular natural organic matter. Mercury sulfide minerals are known to nucleate in anoxic zones, by reaction of the thiol...
Alain Manceau; Cyprien Lemouchi; Mironel Enescu; Anne-Claire Gaillot; Martine Lanson; Valerie Magnin; Pieter Glatzel; Poulin, Brett; Ryan, Joseph N.; Aiken, George R.; Isabelle Gautier-Lunea; Kathryn L. NagyEffects of iron on optical properties of dissolved organic matter
Iron is a source of interference in the spectroscopic analysis of dissolved organic matter (DOM); however, its effects on commonly employed ultraviolet and visible (UV–vis) light adsorption and fluorescence measurements are poorly defined. Here, we describe the effects of iron(II) and iron(III) on the UV–vis absorption and fluorescence of...
Poulin, Brett; Ryan, Joseph N.; Aiken, George R.