Benthic effects of artificial structures deployed in a tidal estuary

Abstract

There has been increased enthusiasm to mitigate the negative effects of fossil fuel consumption through the use of cleaner sources of energy, like marine renewable energy (MRE). Concerns about MRE deployments have motivated research on the ecological effects of these new man-made structures in marine environments. We assessed the extent to which soft-sediment habitats are influenced by the presence of artificial structures deployed in Yaquina Bay, Oregon, USA. Grain size analyses confirmed artificial structures altered the sediment distribution around them with larger grain sizes detected closer to the structures. Infaunal abundances were higher closer to the artificial structures; however, these differences did not result in statistically significant effects on diversity or richness in relation to distance from the structures, nor were they sufficient to cause statistically significant changes in infaunal communities as compared to reference areas. This study provided additional evidence that artificial structures alter their physical environment, but in our study detected differences were less than those observed between the two different regions of the estuary and any effects on infauna were localized and smaller than differences between different regions of the estuary. Conducting these studies in an Oregon estuary provided a good proxy for estimating potential effects of in-stream tidal energy deployments in the Pacific Northwest while also demonstrating the importance of site-specific research.