Spatial patterns of organic matter content in the surface soil of the salt marshes of the Venice Lagoon (Italy)

Salt marshes are crucial eco-geomorphic features of tidal environments as they provide important ecological functions and deliver a wide range of ecosystem services. Being controlled by the interplay between hydrodynamics, geomorphology, and vegetation, the contribution of both organic matter (OM) and inorganic sediments drives salt marsh vertical accretion. This allows marshes to keep pace with relative sea level rise and likewise capture and store carbon, making them valuable allies in climate mitigation strategies. Thus, soil organic matter (SOM), i.e. the organic component of the soil, plays a key role within salt marsh environments, directly contributing to soil formation and supporting carbon storage. This study aims at inspecting spatial patterns of OM in surface salt marsh soils (top 20 cm), providing further insights into the physical and biological factors driving OM dynamics that affect salt marsh survival and carbon sink potential. Our results reveal two scales of variation...