Total organic carbon (TOC) analyzer for characterizing carbon, mercury, and microbial dynamics across peatland and forest ecosystems

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The patterned forest and peatland boreal and sub-boreal regions of Canada are exceptionally important because they store vast amounts of atmospheric carbon dioxide as organic matter in soils that otherwise would contribute to global warming, contain a large volume of the world's potable freshwater, and support forestry and peat natural resource industries. Links between soil carbon (C), greenhouse gas dynamics, ecosystem management, and water quality are inextricable in these ecosystems. Slow, incomplete decomposition of recalcitrant plant material by soil microorganisms, particularly under flooded or wet conditions, results in the production of dissolved organic carbon (DOC) that represents significant and often unaccounted C losses from ecosystems and serve as a biogeochemical link between peatland, upland, and aquatic systems throughout catchments. Methylmercury (MeHg) is an important pollutant in these ecosystems with environmental and human health consequences. In anaerobic wetland soils and aquatic environments where DOC production is greatest, Hg is methlyated through anaerobic microbial activity. Recent evidence has suggested that DOC is an important vector for transporting Hg to specific locations of methylation and binding with DOC may further increase bioavailability. It is becoming clear that in order to understand transport and biomagnification of Hg, we must characterize DOC dynamics throughout watersheds. We are requesting funds for a total organic C analyzer for DOC characterization that will allow us to measure rates of soil decomposition processes, C transfer across northern Canadian forest and wetland ecosystems that are important for Hg transport, and C substrate bioavailability to, and biomass of, soil microbial communities that are responsible for mineralization of organic matter and release of greenhouse gasses from these ecosystems.