摘要
•Field data and analyses highlight the mutual role of inorganic and organic accretion.•Amount of soil organic matter is very sensitive to the specific analysis method.•Salt-marsh accretion is mainly driven by the inorganic component near the channels.•The organic component largely contributes to salt-marsh accretion in the inner marsh.•Carbon accumulation rate for marshes in the Venice lagoon is about 132 g C m−2yr−1.