The effect of flow velocity on methane production and oxidation in aquatic sediments.

流速对水生沉积物中甲烷产生和氧化的影响。

• 批准号: 412119137
• 负责人: Professor Dr. Andreas Lorke
• 金额: --
• 依托单位: Institut für Umweltwissenschaften
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2018
• 资助国家: 德国
• 起止时间: 2017-12-31 至 2021-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/412119137?language=en
• 关键词: effect; flow; velocity; methane; production

Inland waters are important components of the global carbon cycle. Emissions of the greenhouse gas methane (CH4) from inland water bodies are of growing global concern, because of their impact on climate change. Recent research efforts aim at improving the process-based understanding of the spatial and temporal dynamics of CH4 emissions from inland waters. Among the open research questions are: What are the driving factors of CH4 emission dynamics and how are they influenced by global change and anthropogenic alterations of aquatic systems, like river damming or reservoir construction? Many of the factors that are currently considered to affect the rates of methane production, oxidation and emission from aquatic sediments are directly or indirectly related to flow velocity. The flow-dependence of the factors and underlying processes, however, has not been considered explicitly. In this project we will use novel experimental mesocosm systems to study the flow-dependence of these processes in a series of targeted laboratory experiments. The experimental setup simulates the environmental conditions to which aquatic sediments are exposed in a hydraulic gradient from fast-flowing (lotic) to still water (lentic) ecosystems. Such transitions occur, for example, along longitudinal gradients in river impoundments as a consequence of damming. The experiments aim to detangle the effects of flow velocity from the processes that contribute to the overall methane budget in the sediment and the sediment-water interface. The results will be implemented into a process-based model. Besides relevant biogeochemical parameters, also flow velocity (near-bed turbulence) will be considered as an explicit boundary condition of the model. While the model will be validated using the data obtained from laboratory experiments, the conceptual framework by which flow velocity affects methane emissions from different types of aquatic ecosystems will be analyzed with a system-analytical approach.

内陆沃茨是全球碳循环的重要组成部分。内陆水体排放的温室气体甲烷（CH 4）因其对气候变化的影响而日益受到全球关注。最近的研究工作旨在增进对内陆沃茨甲烷排放的时空动态的基于过程的理解。开放的研究问题包括：甲烷排放动态的驱动因素是什么，它们如何受到全球变化和人为改变水生系统的影响，如河流筑坝或水库建设？目前被认为影响水生沉积物中甲烷产生、氧化和排放速率的许多因素都与流速直接或间接相关。然而，流动的因素和基本过程的依赖性，并没有被明确考虑。在这个项目中，我们将使用新的实验围隔系统，研究这些过程中的一系列有针对性的实验室实验流量的依赖性。实验装置模拟的环境条件下，水生沉积物暴露在一个水力梯度从快速流动（lotic）静水（lentic）生态系统。例如，由于筑坝，这种过渡沿河流蓄水池中的纵向梯度沿着发生。实验的目的是从有助于沉积物和沉积物-水界面的总体甲烷预算的过程中理清流速的影响。 结果将纳入一个基于进程的模式。除了相关的地球化学参数外，流速（近床湍流）也将被视为模型的显式边界条件。 虽然该模型将使用实验室实验获得的数据进行验证，但流速影响不同类型水生生态系统甲烷排放的概念框架将采用系统分析方法进行分析。