Methane Emissions from Impounded Rivers: From measurements to models

内陆水体的甲烷排放日益引起全球关注，因为调查显示热带水库的排放量很高，最近的研究表明温带水体的潜力很大。在萨尔河进行的第一次初步研究测量的通量超过全球预算中使用的估计数一个数量级。在这个项目中，我们将调查甲烷从沉积物到萨尔河地表水和大气的通量和途径。在基于过程的方法中，我们将确定和量化控制溶解甲烷在水体中的潜在积累及其释放到大气中的相关环境条件。将在从河流流域到单个气泡的空间尺度上进行实地测量，并辅之以实验室实验和数值模拟。我们将进一步量化溶解甲烷和气泡通量对溶解氧水质的影响。特别强调气泡扰动过程，即气泡介导的沉积物-水通量。该项目的目的是作为一个参考研究，评估甲烷排放量的河流系统的人为改变。

Methane emissions from inland water bodies are of growing global concern since surveys revealed high emissions from tropical reservoirs and recent studies showed the potential of temperate water bodies. First preliminary studies at the River Saar measured fluxes that exceed estimates used in global budgets by one order of magnitude. In this project we will investigate the fluxes and pathways of methane from the sediment to the surface water and atmosphere at the River Saar. In a process-based approach we will indentify and quantify the relevant environmental conditions controlling the potential accumulation of dissolved methane in the water body and its release to the atmosphere. Field measurements, complemented by laboratory experiments and numerical simulations, will be conducted on spatial scales ranging from the river-basin to individual bubbles. We will further quantify the impact of dissolved methane and bubble fluxes on water quality in terms of dissolved oxygen. Special emphasize will be put on the process of bubble-turbation, i.e. bubble-mediated sediment-water fluxes. The project aims at serving as a reference study for assessing methane emissions from anthropogenically altered river systems.