MARSH ELEVATION AND ACCRETION DYNAMICS ALONG ESTUARINE SALINITY GRADIENTS: OBSERVATIONAL AND EXPERIMENTAL STUDIES

Abstract

Chesapeake Bay marshes are threatened by sea level rise and have experienced degradation as a result of saltwater intrusion and increased water levels. Rates of elevation and accretion change and vegetation communities may be affected by salt water intrusion and other processes as a result of sea level rise. An observational study of the Nanticoke River, a tributary to the Chesapeake Bay, utilizing surface elevation tables (SET) reflected that during the course of a two year study period, rates of marsh elevation change differed significantly along an estuarine salinity gradient. Surface elevation of oligohaline marshes decreased during the monitoring period and were significantly different from mesohaline marshes which increased in elevation. An experimental study in Patuxent River tidal freshwater marshes in which plots were irrigated with saltwater indicated that with saltwater intrusion vegetation communities may become less diverse.