Research Objectives:
Dissolved organic matter (DOM) is a significant chemical component in aquatic systems because it acts as an important carbon source for microorganisms, absorbs harmful radiation in sunlight, is able to complex metals, and can participate in important biogeochemical redox reactions. This project will study the biogeochemical cycling of DOM in Pony Lake, a small coastal antarctic pond on Cape Royds.
Because there are no higher plants present at this site all of the DOM in this lake is microbially derived from photoautotrophic, heterotrophic, and mixotrophic organisms. Thus, Pony Lake is an ideal site to study the effect of photolysis, redox changes, and microbial processes on the composition and character of the DOM pool. Pony Lake’s abundant levels of DOM (50-100 mg/L as C) and proximity to the laboratory resources at McMurdo Station, makes it an ideal site to collect an International Humic Substances Society (IHSS) fulvic acid standard. Unlike other IHSS standards, this standard will not contain DOM components derived from higher land plants.
This work is expected to greatly increase understanding of DOM dynamics in the biogeochemical cycling of carbon. This research will also provide much needed information regarding the relationship between microbial diversity and DOM biogeochemistry. If the approach is successful, the group will have developed a methodology that can be utilized by other scientists to study DOM dynamics in other types of systems. Moreover, making this DOM material available to the scientific community through the IHSS will ultimately advance our knowledge of the reactivity of DOM in aquatic systems.
The project will also involve middle school science students by allowing them to be active participants through the Internet, while we are in the field, and by “shadowing” scientists back home in their labs while conducting the assays.
