Internal tides as a structuring factor of faunal patterns in submarine canyons

5th International Network for Submarine Canyon Investigation and Scientific Exchange International Symposium (INCISE), 14-18 June 2021Submarine canyons are listed as topographical features that may support vulnerable marine ecosystems (VMEs), including cold-water coral reefs. Effective spatial management and conservation of VMEs requires accurate distribution maps and a deeper understanding of the processes that generate the observed distribution patterns. Canyons are recognised as sites of intensified hydrodynamic regimes, with internal tides linked to enhanced mixing and nepheloid layer production: processes associated with faunal distributions. Canyon faunal distributions also respond to physical oceanographic (water mass characteristics and hydrodynamics) gradients. Internal tides generate large local variations in water mass characteristics by their movement along the canyon. Despite the growing evidence for the role of internal tides in generating heterogeneity in environmental conditions parameters of internal tide dynamics have rarely been included in studies of canyon fauna. Here we investigate if spatial patterns in internal tide dynamics and associated environmental variability induced by the internal tide, explain variation in spatial patterns of species richness and assemblages in a deep-sea canyon. We take an interdisciplinary approach utilising biological, oceanographic and bathymetric derived datasets to undertake high-resolution predictive modelling and community analysis of epibenthic assemblages within Whittard Canyon. Results show that spatial variability in depth (and its covariates), seafloor characteristics and internal tide dynamics interact at different scales to determine spatial patterns in epibenthic fauna. The results further support the role of the internal tide as a structuring force of assemblages and diversity by generating both spatial and temporal gradients in food supply and water mass characteristicsPeer reviewe