ESTIMATES OF ACCRETION RATES AND ORGANIC CONTENT OF SALT MARSH ISLANDS IN SOUTHERN NEW JERSEY

Sea level rise (SLR), accelerated by anthropogenic climate change, is one of the major threats facing coastal marsh ecosystems. The permanent inundation of salt marshes or conversion to mud flats will result in a loss of critical ecosystem services, such as carbon sequestration and coastal protection. Southern New Jersey experiences a higher rate of SLR compared to the global mean, making salt marshes in this area more susceptible to inundation. This study aims to measure the impact that sea level rise has on the marshes of Seven Mile Innovation Lab (SMIIL) near Cape May, New Jersey by finding the accretion rates at two locations: Gull and Shark islands. A radionuclide dating analysis will be done on two sediment cores from each island following a procedure similar to the methods used in Boyd et al. (2017) and Landis et al. (2016). Data will be collected on isotopic concentrations of Lead-210, Cesium-137, Americium-241, and Beryllium-7. Previous studies have illustrated the valuable role that these isotope markers play in identifying rates of vertical marsh accretion. Isotopic concentration over depth will be used to determine multidecadal accretion rate on each marsh island. Bulk density and loss on ignition (LOI) measurements will be completed to find the organic matter content in each core. These results will then be used to understand the accumulation of both mineral sediment and organic matter and the role of each on accretion rate. Comparing the findings of this investigation with rates of local sea level rise will allow our team to determine the inundation risk of these two marsh islands.