摘要：Freshwater reservoirs, in particular tropical ones, are an important source of methane (CH 4 ) to the atmosphere, but current estimates are uncertain. The CH 4 emitted from reservoirs is microbially produced in their sediments, but at present, the rate of CH 4 formation in reservoir sediments cannot be predicted from sediment characteristics, limiting our understanding of reservoir CH 4 emission. Here we show through a long-term incubation experiment that the CH 4 formation rate in sediments of widely different tropical reservoirs can be predicted from sediment age and total nitrogen concentration. CH 4 formation occurs predominantly in sediment layers younger than 6-12 years and beyond these layers sediment organic carbon may be considered effectively buried. Hence mitigating reservoir CH 4 emission via improving nutrient management and thus reducing organic matter supply to sediments is within reach. Our model of sediment CH 4 formation represents a first step towards constraining reservoir CH 4 emission from sediment characteristics.
