INVESTIGATION OF TERRESTRIAL CARBON CYCLING IN MAINE COASTAL ENVIRONMENTS THROUGH THE LAST 5,000 YEARS

Sediment cores collected from coastal Maine reveal a varied and dramatic history of sea level over the last 12,000 years. Sprague Marsh, a salt marsh on the Phippsburg peninsula in Maine, has a ~6,000 year record of sediment deposition. This study examines changes in terrestrial and aquatic carbon cycling at Sprague Marsh for the last 5,000 years. Sediments from two 3m long cores taken from the salt marsh were analyzed for leaf wax lipid biomarkers, C/N ratios, and stable carbon and nitrogen isotope composition to detect shifts in organic input, deposition, preservation, and burial through time.

Preliminary data indicate that higher plant leaf wax biomarkers are significantly more abundant in terrestrial, organic-rich peat sediments than in sandy, marine derived sediments, suggesting that the total concentration of organic material correlates to different depositional environments. The leaf wax lipid biomarker compositions will be coupled with compound specific d13C analysis to evaluate carbon cycling within the salt marsh sediments at Sprague Marsh.