The Rate of Accretion and Spatial Distribution of Sediments In the Great Sippewisset Salt Marsh

Salt marshes provide many important ecosystem services, yet they are endangered directly and indirectly by human activity. Maintaining an accretion rate greater than the accelerating rate of mean sea level rise is necessary for marshes to avoid “drowning. ” In this project, I estimated the accretion rate of Great Sippewisset Marsh and observed the effects of location relative to the sediment source and tidal channel, elevation, tide magnitude, and marsh grass coverage on the spatial distribution of sediments in the system. I also quantified the importance of inorganic and organic contributions to marsh accretion. I found that the GSM is accreting at a rate that surpasses the rate of sea level rise. The data revealed a positive correlation of sediments deposited with hours of tidal flood coverage and negative correlations with distance from the sediment source (the Falmouth coast) and distance from the tidal channel. There was no correlation of sedimentation with Spartina patens density. The availability of inorganic sediment decreased with distance from the source. I determined the biggest contributor to marsh accretion to be the below ground biomass of S.patens