Twin Cities Seminar

Dissolved Organic Matter Bioavailability in Minnesota Lakes


Seth Thompson
PhD Candidate, Water Resources Science

May 5, 2017


Often greater than 50% of the organic carbon available to organisms in aquatic ecosystems is provided by allochthonous (terrestrial) carbon sources. However, little is known about how the reactivity of this carbon is modified by aquatic organisms. With the growing recognition of the role of inland waters in processing organic carbon, it is increasingly important to understand the controls on organic carbon transformations. One way that terrestrial carbon can be transformed is by microbial uptake, but the importance of this mechanism remains controversial. Furthermore, the fundamental controls on this potential mechanism of carbon transformation, such as its sensitivity to environmental factors like temperature, nutrient conditions, and pH remain unclear. Here I present results from my dissertation work examining the impact of environmental conditions and nutrient composition on the degradation rates of dissolved organic matter in several lakes across the state of Minnesota.

Seth Thompson is a Ph.D. candidate in WRS working with Dr. Jim Cotner. He graduated from the University of Minnesota with a bachelor’s degree in Ecology Evolution and Behavior in 2011. He completed his M.S. in WRS in 2014 by quantifying the relative extractability of organic nutrients from North American grassland soils. His research interests are firmly grounded in understanding the connections between terrestrial and aquatic ecosystems, particularly in relation to carbon and phosphorus biogeochemistry.