Santona studied the origin of the methane that accumulates every summer at the thermocline of Lake Geneva. Methane is typically produced in anoxic conditions, in absence of oxygen. It is then puzzling to foind methane building up in the lake water column where oxygen is plentiful. Is this methane transported from the shore, where plenty of methane is produced in the anaerobic sediments? But is this even possible for such a large lake that methane gets transported over tens of kilometers? Instead, is this evidence for oxic methane production, a low-rate but demonstrated set of microbial pathways by which methane can be procuded in the presence of oxygen?
Spoiler… Khatun, S., Berg, J.S., Jézéquel, D., Moiron, M., Escoffier, N., Schubert, C., Bouffard, D. Perga, M.-E. (in Press). Long-range transport of littoral methane explains the metalimnetic methane peak in a large lake. Limnology and Oceanography.