Salt marshes are highly valuable Blue Carbon ecosystems in the transition zone between marine and terrestrial environments. They play an important role in mitigating climate change due to high carbon sequestration rates through photosynthetic CO2 uptake. However, it is poorly understood when and under which conditions they act as sinks or sources for other greenhouse gases like CH4 and N2O. A complex interplay of abiotic and biotic factors characterizes the biogeochemistry of these dynamic coastal wetland ecosystems. This interplay is in turn controlled by elevation in respect to mean high water level and the resulting inundation frequency.