Response of belowground carbon, sulphur and iron cycling in fen soils

气候模型预测，温带和北方纬度地区夏季干旱和强降雨将增加，这可能会改变湿地的水文和氧化还原状况，而湿地是最重要的陆地碳储存库。干旱和再湿润以及潜在的淹没对生态系统生产和地下碳循环的影响以及与氧化还原过程的耦合，特别是硫和铁的氧化还原过程，迄今为止还没有得到很好的理解。在这个项目中，将通过实验改变湿地的水文状况，并分析和模拟其对碳循环的影响。为此，将在操作期间和之后对土壤含水量、温度和呼吸速率的变化进行量化。呼吸，即氧气，硝酸盐，硫酸盐，三价铁，腐殖物质，相关的电子受体的可用性，生产和消费进行了研究，因为它们的动态强烈影响甲烷生产。一项实验室研究将用于分析一系列温度、干燥强度和持续时间对呼吸的影响。所获得的数据将与以前的控制围隔和实地研究的数据相结合，以模拟水文变化对碳循环和甲烷动态的影响，使用生态系统模型ECONORTH。参数化和测试的模式将被用来模拟和分析在干燥和再湿润过程中发生的地球化学过程的相互作用，以及对碳循环的影响，在十年的时间尺度上。

Climate models predict increases in summer drought and intensive rainfalls in temperate and northern latitudes, which may alter the hydrologic and redox regime of wetlands, the single most important terrestrial carbon storage. The impact of drying and rewetting and potential inundation on ecosystem production and belowground carbon cycling and the coupling with redox processes, in particular of sulfur and iron, is not well understood to date. In this project the hydrologic regime of a wetland will be altered experimentally and the consequences on carbon cycling be analyzed and simulated. To this end, changes in soil water contents, temperatures and respiration rates will be quantified during and after manipulation. The availability, production, and consumption of relevant electron acceptors for respiration, i.e. oxygen, nitrate, sulfate, ferric iron, humic substances, is studied, as their dynamics strongly influences methane production. A laboratory study will serve to analyze the impact of a range of temperatures and drying intensity and duration on respiration. The obtained data will be combined with the data of the previous controlled mesocosm and field study to simulate the impact of hydrologic change on carbon cycling and methane dynamics using the ecosystem model ECOSYS. The parameterized and tested model will be used to simulate and analyze the interaction of biogeochemical processes occurring during drying and rewetting and the impact on carbon cycling on the decadal time scale.