The Effects of Light Availability and Dissolved Organic Carbon Concentration on Methane Dynamics in Icelandic Lakes

摘要: Freshwater lakes are increasingly recognized as significant sources of methane to the atmosphere. Methane oxidation (consumption of methane) can serve as an important regulator of methane emission, but we know relatively little about what regulates this process in freshwater lakes. Recent studies suggest that algal productivity and dissolved organic carbon (DOC) concentrations may influence both methanogenesis (production of methane) and methane oxidation. Methane oxidation can be coupled to photosynthesis and increased DOC can provide electron acceptors necessary for oxidation pathways. However, both algal productivity and increased DOC can elevate organic matter substrates thus fueling methanogenesis. Our objective was to compare the rates of methane production and consumption in the presence of increased photosynthetic activity and increased DOC concentrations. We hypothesized that …