Blue Carbon in Freshwater / Brackish Marshes on the Barrier Islands of Virginia: Aboveground Net Primary Productivity and Carbon Pools

BLUE CARBON IN FRESHWATER / BRACKISH MARSHES ON THE BARRIER ISLANDS OF VIRGINIA: ABOVEGROUND NET PRIMARY PRODUCTIVITY AND CARBON POOLS Emily Caitlin Adams Old Dominion University, 2015 Director: Dr. Frank P. Day “Blue carbon” is a relatively new concept describing carbon distributed tidally and sequestered via net production within coastal ecosystems, including seagrass beds, mangrove forests, and salt-water marshes. These systems sequester carbon at least 10 times faster than terrestrial systems. Fresh to brackish wetlands that receive irregular tidal influence due to overwash and storm events have not been typically studied as blue carbon systems. My objective was to quantify carbon pools within four interdunal fresh to brackish marshes on Hog Island, Virginia to determine their blue carbon potential. Marshes 1 and 2 were farthest from the ocean, below and above a berm respectively. Marshes 3 and 4 were closest to the ocean, below and above a trail berm respectively. Marshes 1 and 2 were hypothesized to be more accessible to overwash events than Marshes 3 and 4. Aboveground primary production was determined via harvests throughout 2013. No significant differences in production were found among marshes (F = 1.116; p = 0.355). Values for primary production ranged from 156 g C m yr (marsh 3) to 284 g C m yr(marsh 2). Belowground biomass was measured with cores extracted in August, 2013. Marsh 2 had significantly more belowground biomass than all the other marshes (F = 9.425; p < 0.0005). Decomposition was measured with litterbags collected throughout the year. All marshes exhibited slow exponential decay (k = 0.0007, 0.002, 0.001, 0.001). Soil carbon values were highly variable with marsh 4 storing the most carbon. Carbon sequestration potential was calculated using auxiliary belowground data. These values do not include carbon exported from the marshes but suggest that carbon could be sequestered at high rates, similar to blue carbon systems.