Marie came to the USGS in September 2002 as a postdoctoral fellow to study the bioavailability and bioaccumulation of metals in freshwater food webs. Her work focused on understanding how metals are transferred through food webs and how trophic position in a food web influences exposure to metals.
Marie used nitrogen and carbon stable isotopes to show that cadmium, in contrast to copper, could be magnified along certain freshwater food webs. This suggests that processes that drive Cd trophic transfer are more complex than that of organo-metals, metalloids and organic contaminants.
In addition to her work on metal trophic transfer, she refined an approach that involves the use stable metal isotopes (rather than radioisotopes) to describe accumulation and loss dynamics in freshwater invertebrates. Characterization of bioaccumulation dynamics is critical to understanding risks associated with contaminant exposure in organisms. For instance, this tracing technique allowed showing that a slow rate constant of loss for Cu likely explains the elevated levels of this toxic trace metal found in molluscs in nature, and that diet is an important bioaccumulation pathway for metals for several aquatic species.
She used biodynamic modeling and the enriched stable isotope tracers in novel ways to understand the fate and effects of nanosized metals in aquatic organisms as well as to investigate how the geochemical properties of mineral particles consumed by organisms affect their bioavailability.
Science and Products
Environmental Health-Minerals
Minerals Science Team
Study Reveals Processes that Control Uranium Bioavailability in a Freshwater Snail—Relevance to Aquatic Biota in the Grand Canyon Area
Science and Products
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Environmental Health-Minerals
This project provides scientific data about how contaminants, that might originate from mineral resource activities, are transported through the environment; their pathways of exposure; and where they ultimately end up. Contaminant exposures can originate from transportation, storage, extraction, and waste management mineral resource activities. This project distinguishes perceived health risks to...Minerals Science Team
The Minerals Integrated Science Team focuses on contaminant exposures in the environment that might originate from mineral resource activities including, transportation, storage, extraction and waste management. Perceived health risks to humans and other organisms will be distinguished from actual risks, if any. If actual risks are identified the science produced by this team can inform how to...Study Reveals Processes that Control Uranium Bioavailability in a Freshwater Snail—Relevance to Aquatic Biota in the Grand Canyon Area
Scientists refined an existing speciation model to identify key biogeochemical processes controlling dissolved uranium bioavailability to a freshwater snail. This information is important to advance current understanding and prediction of the ecological risk posed by uranium mining to freshwater ecosystems, including federally managed lands such as in the Grand Canyon area. - Data
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