SPATIAL DISTRIBUTION OF SURFACE WATER SALINITY, NUTRIENTS, CHLOROPHYLL A AND ALGAE ON SAPELO ISLAND

Climate change predictions suggest that weather patterns are going to get erratic with increased frequency of intense storms. These storms, coupled with an expected sea level rise will result in increased coastal and barrier island inundation with seawater. Seawater incursion will increase salinity and convert fresh and brackish water environments into saline habitats. This change can cause significant stress and reduction in biodiversity of these aquatic systems. There is an urgent need to understand the effects of climate change on barrier islands and the species that inhabit them. The goal of this project is to map the spatial and temporal distribution (and correlations) of salinity, algae and chlorophyll-a on Sapelo Island, Georgia. Field physicochemical parameters were measured in the field using handheld probes (YSI multiparameter probe and LabQuest 2 instruments) while lab samples were analyzed using benchtop equipment. Algae and chlorophyll-a were measured in the field using the Bentho Torch while lab samples were analyzed using an Algae Guard. The highest nitrate, phosphate, nitrite, and ammonium were 60 mg/L, 1.3 mg/L, 11 mg/L, and 11 mg/L respectively. Biomass as chlorophyll-a had a maximum of 593 µg/L with diatoms dominating at over 70% of the sampled sites. Results to date show negative correlations between chlorophyll-a on one hand and salinity, nitrate and ammonium on the other. A positive correlation was observed between diatoms, green algae and phosphates. These results imply potential habitat impacts of global climate change on barrier islands, although more data is still required and currently being collected.