INTERPRETING SEA-LEVEL RISE AND RATES OF VERTICAL MARSH ACCRETION IN A SOUTHERN NEW-ENGLAND TIDAL SALT-MARSH

An investigation of marsh accretion rates on a New England type high m arsh (Earn Island Wildlife Management Area, Stonington, Connecticut) r eveals that this system is sensitive to changes in sea level and storm activity and the pear can accurately record rates of relative submerg ence as determined by tide gauge records over intervals of 2-5 decades . The results also suggest that the relationship between the accretion deficit and plant community structure is important when utilizing pea t records to reconstruct historic sea-level curves within stable Spart ina patens high marsh communities. In systems where major vegetation c hanges are prominent over short periods of time (<50 years), interpret ations of sea-level rise should be limited to the system in which they are developed unless careful vertical controls can be maintained on t he data and multiple datable horizons can be identified within the sub strate. The results of this investigation further show that in a stabl e Spartina patens community within this particular system there is lit tle vertical translocation of Cs-137, making this isotope a powerful t ool for assessing rates of vertical marsh development since 1954. (C) 1998 Academic Press.