The Impact of Benthic Organisms to Improve Water Quality in the Indian River Lagoon, Florida

The Living Docks restoration program was implemented in the Indian River Lagoon (IRL), Florida, with the goal of affixing oyster restoration mats to dock pilings to promote the growth of filter feeding benthic organisms which can help improve local water quality. However, the relationship between IRL water quality parameters and the presence of filter feeders on the mats is not entirely clear. This study investigates the presence of benthic organisms on eight Living Docks which were deployed throughout the central part of the IRL. Environmental factors (e.g., water salinity, turbidity, pH, and temperature) were collected from the closest available water station to each dock. The main goal was to identify the presence and overall change in percent cover of specific benthic organism(s), those which are known filter feeders, in relationship to environmental parameters. Among functional groups which were identified, barnacles, biofilms, encrusting bryozoans (EBs), oysters, and sponges demonstrated significantly higher cover than the others. Barnacles were higher in abundance at specific dock locations and an increased water pH (up to 8.1), turbidity, and temperature. EB presence was positively impacted by salinity but did not respond to changes in turbidity or temperature within the measured ranges. Oysters were not observed to be impacted by any of the factors within measured ranges. Sponges had sustained abundance in half of the docks in this study. However, they did not respond to any of the environmental factors within measured ranges in different seasons. Results from this study can help target future Living Dock locations which will provide the best environment for the recruitment of filter feeding organisms.