Phosphorus regulation of methane oxidation in water from ice-covered lakes

Winter methane (CH4) accumulation in seasonally ice-covered lakes can contribute large episodic emissions to the atmosphere during spring ice melt. Biological methane oxidation (MOx) can significantly mitigate such CH4 emissions, but despite favorable CH4 and O2 concentrations, MOx appears constrained in some lakes for unknown reasons. Here we experimentally test the hypothesis that phosphorus (P) availability is an important factor limiting MOx and explaining differences in ice-out emissions among lakes. Water sampled at the ice-water interface from 12 Swedish lakes was incubated with addition of phosphate and methane. Methane oxidation rates were monitored as well as changes in microbial population.