Loss for Gain? The Potential Importance Of Marsh Creekbank Erosion For Marsh Platform Survival

We have been measuring watershed inputs and the along-estuary distribution of suspended sediments for over 20 yrs in the Plum Island Estuary, MA, U.S.A. Non-conservative distribution of sediments, chlorophyll and particulate organic carbon (POC) along the length of the estuary and up into 1^st and 2^nd order blind tidal creeks shows an internal source of these materials. ¹⁴C dating shows that the most likely non-chlorophyll POC source is peat eroding from the marsh creekbanks. Accretion studies across the marsh platform show a relative pattern of decreasing sediment and increasing organic matter deposition with increasing distance from the flooding creek. ¹⁴C dating of surficial fine organic carbon on the marsh platform shows an ancient source of material, most likely the peat eroded from marsh creekbanks. Empirical studies and modeling show that with increased sea-level rise and limited availability of sediments, marsh lateral erosion of estuarine waterbodies will increase thereby augmenting sediment availability and perhaps the survival of the remaining platform marshes.