Organic matter and sediment properties determine in-lake variability of sediment CO2 and CH4 production and emissions of a small and shallow lake

Abstract

Inland waters are significant sources of CO2 and CH4 to the atmosphere, following recent studies this is particularly the case for small and shallow lakes. The spatial in-lake heterogeneity of CO2 and CH4 production processes and their drivers in the sediment yet remain poorly studied. We thus measured potential CO2 and CH4 production in sediment incubations from 12 sites within the small and shallow crater lake Windsborn in Germany as well as fluxes at the water-atmosphere interface at four sites. Production rates were highly variable and ranged from 7.2 and 38.5 µmol CO2 g C−1 d−1 and from 5.4 to 33.5 µmol CH4 g C−1 d−1. Fluxes lay between 4.5 and 26.9 mmol CO2 m−2 d−1 and between 0 and 9.8 mmol CH4 m−2 d−1. Both CO2 and CH4 production rates and CH4 fluxes were significantly negative (p