MetOx - Methane in Oxic surface waters

The objective of this project is ultimately to test for the presence of CH4 production under oxic conditions (Grossart et al. 2011) at a global scale as well as on a temporal scale. We will achieve this by following the sampling regime and modeling techniques outlined in DelSontro et al. (2017) in lakes across the Gleon network. Assuming that vertical diffusion is negligible during stratification and that CH4 ebullition does not readily occur in pelagic waters, we will first test the physical transport model that described the spatial heterogeneity of surface CH4 in lakes of Quebec with data from Gleon lakes. Second, we will use the stable carbon isotopic signature of surface CH4 in each lake to investigate the presence of CH4 production relative to CH4 oxidation in the oxic surface waters of these lakes. We will sample several times over the stratified period to look at any temporal trends in surface CH4 dynamics during this period. We also hope to investigate CH4 dynamics in a few of the systems in more detail (i.e., vertically) in order to contribute to the overall knowledge gained by the surface sampling in a large number of Gleon lakes.