Paper No. 8
Presentation Time: 9:45 AM
COMPARING DROWNED FORESTS AND BURIED PEAT AS RECORDS FOR SEA LEVEL CHANGE
As global temperatures rise, coastal communities and wetlands are at risk of inundation from rising sea level. Understanding the historic response of a coastline to sea level rise permits resource managers to anticipate the effects of climate change on fragile tidal wetlands and coastal developments. Globally averaged tide-gauge records from the 20th century show a mean rate of sea level rise of 1.8 mm/yr. However, satellite altimeter observations over the last 20 years show a rapid increase in to 3.11 ± 0.6 mm/yr. Furthermore, because of differences in isostasy, sediment supply, wave climate and tide regime, the effects of sea level rise do not manifest evenly along coastlines. Therefore, it is important to assess changes on a site-by-site basis. In this study, we compare two independent proxies to measure the local-relative rate of sea level rise along the Delaware Estuary coastline between the bay mouth and the Chesapeake & Delaware Canal where historic tide gauge records do not exist. Measurements using C14 dating of basal Spartina sp. peat were compared to results from a dendrochronologic record of drowned Juniperus virginiana (Eastern Red Cedar) trees. The dendrochronologic record provides an independent proxy for assessing relatively recent (<100 yr) changes in local-relative sea level and is inexpensive compared to isotopic dating techniques.