Origin of organic carbon in the topsoil of Wadden Sea salt marshes

Salt marshes in the Wadden Sea store significant amounts of organic carbon (OC), but the origin of this carbon—whether from external sources or locally produced by vegetation—remains unclear. This study reveals that allochthonous OC (AllOC) from sediment sources contributes more to topsoil OC stocks when livestock grazing is absent, while grazing reduces its relative contribution. Additionally, spatial factors like surface elevation and distance to sediment sources influence AllOC contributions, with one salt marsh showing a negative effect of distance to creeks. These findings highlight the importance of geomorphological and land-use factors in determining carbon storage dynamics, offering critical insights for blue carbon crediting and sustainable land management.

Mueller, P., Do, H., Jensen, K., & Nolte, S. (2019). Origin of organic carbon in the topsoil of Wadden Sea salt marshes. Marine Ecology Progress Series, 624, 39–50. https://doi.org/10.3354/meps13009