Benthic chlorophyll concentrations and gross oxygenic photosynthesis rates in surficial estuarine intertidal sediments at sites on Sapelo Island and near the Satilla River from January, April, June and July 2001

Seasonal patterns of estuarine creek-bank and intertidal marsh benthic chlorophyll and gross oxygenic photosynthesis were investigated at several sites on Sapelo Island and the Satilla River in coastal Georgia. Benthic chlorophyll were measured in the bulk surface centimeter depth of sediment. Gross oxygenic photosynthesis rates were integrated over 100 um resolution measurements below the sediment water interface using oxygen microelectrodes. Several relatively pristine sites on Sapelo Island (Moses Hammock, Dean Creek and Marine Institute) and a presumably heavily impacted site (Dover Bluff) show similar levels of chlorophyll concentration and photosynthesis rate across bank and marsh zones with higher photosynthetic biomass and activity in the spring season. Nutrient inputs to these study sites are also suggested as a control on gross oxygenic photosynthesis rates as evidenced by a relationship between photosynthesis rate and land-use.