Quantification and regulation of carbon fluxes in Lake Windsborn (Eifel): do hot spots and hot moments of carbon cycling occur in shallow waters?

最近人们发现，小型水生生态系统覆盖的面积比以前认为的要大得多。由于这一事实和它们的高代谢活性，它们很可能是碳的重要汇和甲烷的来源，并可能在气候-生物圈系统中提供相关的反馈。到目前为止，人们对这些系统的作用知之甚少，因为它们处于陆地生态系统科学和湖泊学的学科界限之间。为了开始纠正我们的知识不足，该项目将在一个浅层营养不良模型系统中量化水与大气、沉积物和地表水之间的气体交换，并建立全年二氧化碳和甲烷排放和碳固存的控制。在这一分析中，我们将重点放在对年度碳平衡有重大影响的时期和地区，如冰破裂、春季和秋季。为此，将采用传感器系统应用的最新进展和高分辨率气体通量室测量，这将使人们对碳循环的功能有新的认识。碳通量将与环境变量和内部生物和物理动力学有关。此外，我们将重点关注甲烷生成，甲烷氧化和运输，这是这些系统温室增温潜力的关键过程。在这方面，将质量平衡、孔隙水分析和建模、孵化技术和13C稳定同位素平衡的应用相结合，量化这些过程及其对环境条件的依赖。因此，这项研究将解决一个重要的知识缺陷，这个缺陷可能会阻碍对气候-生物圈相互作用的评估。

Recently it has been discovered that small aquatic ecosystems cover much larger areas than previously assumed. Due to this fact and their high metabolic activity, they are most likely significant sinks for carbon and sources of methane and may provide relevant feedback in the climate-biosphere system. The role of these systems is so far poorly understood because they fall between disciplinary boundaries of terrestrial ecosystem science and limnology. To begin rectifying our knowledge deficiency the project will quantify the gas exchange between water and the atmosphere and sediment and surface waters in a shallow dystrophic model system and establish controls on CO2 and CH4 emission and carbon sequestration throughout the year. In this analysis we focus on periods and zones that have great influence on annual balances of carbon, such as ice breakup, spring and fall. To this end most recent advances in the application of sensor systems and high resolution gas flux chamber measurements will be employed that will allow for novel insights in the functioning of the carbon cycle. Carbon fluxes will be related to environmental variables and internal biological and physical dynamics. Moreover, we will focus on methanogenesis, methane oxidation and transport, which are key processes for the greenhouse warming potential of these systems. In this respect, mass balances, pore water analysis and modeling, incubation techniques and application of 13C stable isotope balances are combined to quantify these processes and their dependencies on environmental conditions. The research will thus address an important knowledge deficiency that potentially hampers assessments about climate-biosphere interactions.