Abstract or Keywords
This study investigates benthic impacts of the Piney Point discharge into Tampa Bay by characterizing the benthic environment and identifying associated changes. A time series of water quality measurements and sediment samples were collected along two shore normal transects into Tampa Bay from Port Manatee and Bishops Harbor during the discharge, and thereafter on a monthly basis. In situ measurements showed a pH decrease in close proximity to the discharge during the initial collection as compared to subsequent collections. Sedimentology was used to characterize the benthic environment to identify any changes in sediment source(s), deposition patterns and rates. Results indicate a variety of sediment types and the influence of anthropogenic activities (dredging/ shipping traffic) along the Port Manatee transect. Benthic foraminifera assemblages and indices, utilized as a bioindicators of ecological quality, indicate that sites near Port Manatee have low abundance (<30 individuals) and few to no living individuals. Sites further from Port Manatee have increased abundance, but are dominated by Ammonia spp. (low O2 and stress tolerant). Sediment and fish samples were analyzed for short-lived radioisotopes to determine if activities were elevated due to the discharge and subsequently to trace the spatial distribution and incorporation into the ecosystem (fish). Sediment samples have elevated activities in Port Manatee and Bishops Harbor that may be attributed to natural and/or anthropogenic influences including, but not limited to, groundwater discharge and input of phosphate-rich water/sediments, such as the Piney Point discharge. Radioisotope baselines will determine the relative contribution of the Piney Point discharge toward the elevated activities and its potential as a tracer of the discharge. Integration with previous benthic studies (baselines), and collaborator data provide a comprehensive understanding of the event, its potential impacts, and evolution over time.