Underwater Noise <orchestra, ecOsystem Responses to Constant offsHorE Sound specTRA>

The increase of anthropogenic underwater noise (AUN) through oil exploitation, shipping and the construction and operation of offshore wind farms (OWF) has altered the marine acoustic environment significantly and is now a global challenge. AUN can harm a variety of taxa by impairing an individual's physiology directly, as well as interfere with fitness relevant behaviours such as communication, orientation, predator avoidance and foraging, all potentially leading to increased mortality and decreased reproduction. Benthic and planktonic invertebrates play a key role as a dynamic link between lower and higher trophic levels in the world's oceans. However, data on the effects of especially continuous AUN on these organisms are scarce, which impedes our predictive capabilities on the effects of AUN on ecosystem functioning and the services marine ecosystems provide. ORCHESTRA combines interdisciplinary expertise on plankton and benthos, and underwater acoustics from six scientific institutions of four European countries. We will fill the knowledge gaps by conducting field studies across basins in order to compare behavioural and physiological impacts on invertebrate key species and communities. Combined with the field surveys, experiments will be carried out in a multiple stressor approach including AUN and warming scenarios, to allow cross-basin comparisons with different temperature regimes. Novel setups will be implemented in order to transfer AUN experiments from the laboratory into the field in order to test AUN effects under realistic conditions. The resulting data will be combined with information on local soundscapes and species abundances to identify in turn areas with the largest risks of being affected by AUN. Our results can be implemented in strategies for the mitigation of AUN impacts on marine ecosystem key species and communities and will contribute to the development of criteria and measures to reach Good Environmental Status in European waters.