Limnology, Department of Ecology and Genetics, Uppsala University, Uppsala, Sweden.
Laboratory of Aquatic Ecology, Department of Biology, Federal University of Juiz de Fora, Juiz de Fora, Brazil.
Sci Rep. 2019 Jul 29;9(1):11017. doi: 10.1038/s41598-019-47346-7.
Freshwater reservoirs, in particular tropical ones, are an important source of methane (CH) to the atmosphere, but current estimates are uncertain. The CH emitted from reservoirs is microbially produced in their sediments, but at present, the rate of CH formation in reservoir sediments cannot be predicted from sediment characteristics, limiting our understanding of reservoir CH emission. Here we show through a long-term incubation experiment that the CH formation rate in sediments of widely different tropical reservoirs can be predicted from sediment age and total nitrogen concentration. CH 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 emission via improving nutrient management and thus reducing organic matter supply to sediments is within reach. Our model of sediment CH formation represents a first step towards constraining reservoir CH emission from sediment characteristics.
淡水水库，特别是热带水库，是大气中甲烷 (CH) 的一个重要来源，但目前的估计还不确定。水库中释放的 CH 是在其沉积物中由微生物产生的，但目前，从沉积物特征预测水库沉积物中 CH 的形成速率是不可能的，这限制了我们对水库 CH 排放的理解。在这里，我们通过一个长期的培养实验表明，广泛的不同热带水库沉积物中的 CH 形成速率可以从沉积物年龄和总氮浓度来预测。CH 的形成主要发生在年龄小于 6-12 年的沉积物层中，超过这些层后，沉积物中的有机碳可能被认为是有效地埋藏的。因此，通过改善营养物质管理从而减少向沉积物供应有机物来减轻水库 CH 的排放是可行的。我们的沉积物 CH 形成模型代表了从沉积物特征来约束水库 CH 排放的第一步。
