Meeting Abstract

71.3  Friday, Jan. 6  Offshore renewable energy structures as stepping stones for biogeographic change: does larval vertical positioning hold the key? MILLER, RG*; BURROWS, MT; FOX, CJ; INALL, ME; Scottish Association for Marine Science raeanne.miller@sams.ac.uk

The construction of marine renewable energy devices will alter the availability of shallow water hard habitat around the UK. These structures may act as artificial islands, encouraging changes in species ranges as stepping-stones for dispersal across biogeographic boundaries, altering patterns of population connectivity. For marine organisms with pelagic larvae, the vertical positioning of larvae in stratified coastal flow fields can be an important determinant of transport, dispersal, and connectivity. Between-species and between-stage differences in vertical positioning may drive differential transport of larval assemblages, resulting in distinct patterns of connectivity. Building on laboratory measurements of larval sinking rates and three-dimensional plankton sampling, oceanographic modelling techniques explore the influence of vertical positioning on the dispersal of acorn barnacles along the Scottish west coast. Interspecific variation in naupliar density and drag may be a driver of varying depth distributions of both larval and adult communities. Divergence in the vertical positioning of sub-tidal and inter-tidal larvae may also explain previously observed horizontal variations in larval distributions. For many species, larval hydrodynamics and other physiological properties can be important when assessing the potential connectivity or biogeographic impacts of marine renewable energy device installation as well as for the effective development of marine protected areas, a relevant policy objective.