Dr. Steven Morgan, University of California Davis
Larvae of intertidal species develop at sea and must return to adult habitats to replenish populations. Similarly, nutrients, detritus and plankton in productive coastal waters provide important subsidies spurring growth and reproduction of plants and filter-feeding invertebrates that form the foundation of intertidal communities. Together, these factors determine the density and intensity of interactions among community members. In strong persistent upwelling along the western margins of continents, larvae of nearshore species are widely believed to be transported far offshore in surface currents and return to shore during infrequent wind relaxation events limiting recruitment to populations, but recent studies in my laboratory have not supported either tenet of this hypothesis. I show that that surfzone hydrodynamics plays a key role in regulating subsides of food and larvae to nearshore communities by conducting intensive interdisciplinary process studies and numerical simulations at two shores with different surfzone characteristics as well as surveying recruitment a 42 sites along the entire West Coast relative to surfzone characteristics and settlement at 16 of these sites over time.