Impact of Offshore Windfarm Development on Marine Benthos: Interaction with Ecosystem Level Stressors

Project Description:

The expansion of offshore wind energy development is set to play a key role in enabling the UK to achieve net zero by 2050. However, the proposed scale of development poses a significant, and poorly understood, threat to marine benthic (seabed-dwelling) species. Offshore windfarm (OWF) construction, operation and decommissioning generates seabed disturbance in the form of underwater noise and vibration of the seabed, electromagnetic (EM) fields, heat and physical disturbance of the sediment. This is coupled with disturbance from other, widespread and increasing, anthropogenic activities (e.g. demersal fishing, dredging, oil and gas), against a background of climate change pressures (temperature increase, acidification, hypoxia).

Research on the effects of offshore windfarm development on marine benthos is in its infancy with most studies relating to post-construction changes in benthic community structure resulting from physical/structural change of the seabed. Relatively few studies have looked at the effects of other pressures (e.g. seabed vibration) arising from OWF development. These effects may be sub-lethal (e.g. behavioural or physiological) and progressive over time, leading to reduced growth and reproductive output (for example), ultimately impacting ecological functioning and wider ecosystem processes. Furthermore, responses of marine species to anthropogenic disturbance are most commonly determined on a single stressor basis with knowledge of the interaction between multiple stressors being limited.

This project aims to understand the impacts of seabed vibration induced by pile driving during offshore wind farm construction, in combination with other widespread anthropogenic (fishing) and climate change pressures. It builds on ongoing research at the Universities of Hull and Southampton which has shown that noise and seabed vibration (representative of environmental levels of vibration during pile driving) induce physiological and behavioural responses in invertebrates, including changes in burrowing behaviours (bioturbation) that influence important ecosystem processes.

References:

Dannheim, J., Bergstrom, L., Birchenough, S.N.R. et al., 2020. Benthic effects of offshore renewables: identification of knowledge gaps and urgently needed research. ICES J. Mar. Sci. 77, 1092-1108 https://doi.org/10.1093/icesjm

Mazik, K., Curtis, N., Fagan, M.J., Taft, S. & Elliott, M. 2008. Accurate quantification of benthic macro and meio fauna on the geometric properties of estuarine muds by micro computer tomography. J. Exp. Mar. Biol. Ecol. 354:192-201.

Roberts L., Cheesman, S., Breithaupt, T. & Elliott, M. 2015. Sensitivity of the mussel Mytilus edulis to substrate-borne vibration in relation to anthropogenically generated noise. Mar. Ecol. Prog. Ser. 538: 185-195.

Solan, M. Hauton, C., Godbold, J.A., Wood, C.L., Leighton, T.G. & White, P. 2016. Anthropogenic sources of underwater sound can modify how sediment-dwelling invertebrates mediate ecosystem properties. Scientific Reports. 6:20540 — DOI: 10.1038/srep20540 https://www.nature.com/articles/srep20540