Land-atmosphere methane and nitrous oxide exchange of tidal wetlands in the Elbe estuary

Abstract

Tidal wetlands are important ecosystems for climate change mitigation targets. Their high productivity and ability to build up carbon stocks offer pathways to enhance atmospheric carbon removal. Furthermore, tidal salt marshes are associated with low emissions of the potent greenhouse gas methane. On the other hand, their fresh water counterparts are associated with high methane emissions. While, natural tidal wetlands are nitrogen limited, those situated in intensively used agricultural and industrial areas are exposed to enhanced nitrogen loading. Consequently, large ranges in CH4 and N2O land-atmosphere flux magnitudes can occur in estuaries. Uncertainty remains in the spatiotemporal variability of these flux magnitudes as observational data is still limited. Furthermore, the controls of CH4 and N2O flux magnitude and variability and the effect of their interactions are not fully understood in the dynamic tidal wetland ecosystems. In this dissertation, soil-atmosphere-vegetation interactions have been investigated for the tidal wetlands in the Elbe estuary, with the aim to increase our understanding of CH4 and N2O land-atmosphere exchange in these ecosystems.