CARBON SEQUESTRATION RATES OF DIFFERENT MARSH ZONES IN THE SCHOODIC MARSH OF ACADIA NATIONAL PARK, MAINE

Salt marshes are potential carbon sinks but marsh zones can transgress if relative sea level rise exceeds critical thresholds. This research was undertaken in the Schoodic Section of Acadia National Park, Maine, in order to determine which marsh zones have the highest carbon sequestration potential. Nine 60cm cores were taken from the Schoodic Marsh, three each from high, low, and freshwater marsh areas, to use for calculation of carbon sequestration rates. Percent organic carbon was determined using an elemental analyzer. Soil bulk density was also determined and sedimentation rates were calculated based on bulk radiocarbon dates of basal core sediments. Five out of the nine cores have been processed thus far (2 freshwater marsh, 2 high marsh, and one low marsh). The low marsh core had the lowest percentage of organic carbon but the sequestration rate was highest (87.4 g C m^-2 yr^-1) due to a high sedimentation rate. Only a minimum carbon sequestration rate could be calculated for this core due to the radiocarbon date being modern. We used the maximum calibrated 2σ age of 278 years BP, which allowed for the calculation of a minimum sedimentation rate. The two high marsh cores had the lowest carbon sequestration rates (39.0 +/- 6.4 g C m^-2 yr^-1 and 55.1 +/- 6.0 g C m^-2 yr^-1). The two freshwater marsh cores showed intermediate carbon sequestration rates (54.4 +/- 5.6 g C m^-2 yr^-1 and 61.6 +/- 9.0 g C m^-2 yr^-1). The data for this marsh show that carbon storage potential is higher when low marsh overtakes high marsh, but could decrease if high marsh overtakes freshwater marsh. Release of methane in freshwater marsh zones could offset the additional carbon storage potential. The analysis of the remaining four cores will test current findings.