Abstract
This study reports on monitoring surveys conducted at three of the five commercially operating turbines in U.S. waters off Block Island, Rhode Island, U.S.A., with an emphasis on the final, fourth year of a Bureau of Ocean Energy Management sampling program. The monitoring focused on changes to sediments and infaunal and epifauna species abundance, richness, and diversity caused by the presence of the turbine structure. As anticipated, based on a comparison with other study results, far-field changes in benthic conditions were not evident. Clear changes to the seabed sediments and faunal composition manifested only in the immediate footprint of the turbine foundations. Aside from a localized and sustained shift in particle size, little evidence of a temporally or spatially progressive pattern (as a function of distance away from the turbines) of change in seabed physical and biological composition, or on the turbine structures themselves, was found. The lack of a systematic pattern of influence suggests that many of the intra- and interannual differences may be attributed to natural fluctuations, especially the epifauna on the turbine structures. Notably, the faunal dynamics suggest a community in constant flux and, as seen in other studies, lacking a trend toward the formation of a climax community, which is characterized by stable faunal composition. For these dynamic communities, future sampling may consider using a fixed station, repeated measures approach, as has been done in similarly dynamic, intertidal communities to manage these scales of habitat variability.