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Methane emissions from small lakes: Dynamics and distribution patterns (MethDyn)

小湖泊的甲烷排放：动态和分布模式 (MethDyn)

基本信息

批准号：
342123729
负责人：
Professor Dr. Frank Peeters, Ph.D., since 4/2020
金额：
--
依托单位：
GEOMAR Helmholtz-Zentrum für Ozeanforschung Kiel
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2017
资助国家：
德国
起止时间：
2016-12-31 至 2019-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/342123729?language=en
关键词：
Methane emissions small lakes Dynamics

项目摘要

Small lakes have been identified as a significant source of methane in the global methane budget. These lakes have higher methane fluxes per unit area than large lakes and contribute a major fraction of global methane emissions from lakes. However, the estimation of lake-wide methane emissions underlies large uncertainties, because measurements and model approaches that account for the temporal and spatial variability of methane in lakes are rare. The aims of the project are to investigate methane dynamics and distribution patterns in and methane emissions from small lakes as well as to characterize lake properties and to quantify processes that determine the lake-wide methane emissions from small lakes. Thereby, the focus will be on the relative importance and temporal variability of spatial gradients in methane, autumn overturn, and the different flux paths for annual, lake-wide methane emissions. Intensive field experiments will be conducted measuring the internal dynamics, spatial heterogeneity, lake-wide distribution, and temporal variability of dissolved methane and methane emissions that account for the main emission pathways together with abiotic conditions on the example of six lakes having different properties. State of the art measuring techniques (e.g., an eddy-covariance system, single- and multi-beam echosounder, methane and carbon dioxide probes, automated ebullition flux funnels and diffusive flux chambers, an ultraportable greenhouse gas analyzer, oxygen and carbon dioxide optodes) will be combined with intensive water sampling and water sample analysis (dissolved methane, methane isotopic composition, oxidation rates, and other water constituents) to meet the requirements of sufficient temporal and spatial resolution and reliable absolute data on all abiotic parameters and in specific on the dissolved methane concentration. These field experiments will be complemented by numerical simulations of the methane dynamics conducted with a 3D Methane Model. The purpose of the numerical approaches is to simulate horizontal transport, exchange and distribution dynamics of dissolved methane, and the lake-wide diffusive flux of methane to the atmosphere under changing boundary conditions in small lakes as well as to investigate how climate change and different wind forcing affect the diffusive flux of methane to the atmosphere during overturn periods and their relative contribution to the annual, lake-wide emissions.

在全球甲烷预算中，小型湖泊已被确定为甲烷的重要来源。这些湖泊的单位面积甲烷通量高于大型湖泊，占全球湖泊甲烷排放量的很大一部分。然而，对全湖甲烷排放量的估计存在很大的不确定性，因为考虑到湖泊中甲烷的时间和空间变异性的测量和模型方法很少。该项目的目的是调查甲烷在小湖泊中的动态和分布模式以及小湖泊的甲烷排放情况，并描述湖泊的特性，量化决定小湖泊全湖甲烷排放的过程。因此，重点将放在甲烷空间梯度的相对重要性和时间变异性、秋季翻转以及年度全湖甲烷排放的不同通量路径上。将以6个不同性质的湖泊为例，进行密集的野外实验，测量占主要排放途径的溶解甲烷和甲烷排放的内部动力学、空间异质性、全湖分布和时间变异性，以及非生物条件。先进的测量技术(例如涡流协方差系统、单波束和多波束探测仪、甲烷和二氧化碳探头、自动沸腾通量漏斗和扩散通量小室、超便携温室气体分析仪、氧气和二氧化碳光谱仪)将与密集的水样采样和水样分析(溶解甲烷、甲烷同位素组成、氧化率和其他水成分)相结合，以满足关于所有非生物参数，特别是关于溶解甲烷浓度的足够的时间和空间分辨率和可靠的绝对数据的要求。这些现场实验将得到用三维甲烷模型进行的甲烷动力学的数值模拟的补充。数值模拟的目的是模拟不同边界条件下小湖泊中溶解甲烷的水平输送、交换和分布动态，以及全湖甲烷向大气的扩散通量，并研究气候变化和不同的风强迫如何影响翻转期间甲烷向大气的扩散通量及其对年全湖排放的相对贡献。