This is an Accomplishment-Based Renewal award to continue research on the role of hydrodynamical and biological processes during settlement of infaunal invertebrates. The ultimate goal of the research is to determine the spatial scales and hydrodynamical and biological conditions for which substrate selectivity by settling larvae account for observed adult patterns of distribution. The research addresses the following three general questions. 1) Where are competent larvae located within the water column and what is their settlement rate as a function of flow and sediment characteristics? 2) Do larvae actively select preferred substrates over spatial scales of meters in the laboratory and of 100's of meters to kilometers in the field? 3) How is sediment selection accomplished in flow -- that is, are there specific larval behaviors that permit exploitation of the physical regime to facilitate active selection and are there physical conditions for which selection is impossible? Experiments to address these question will be conducted while continuing the study of sediment selection capabilities of particular infaunal invertebrates as a function of life history characteristics and habitat affinity of adults. The intent is to iterate on generalizations regarding the role of settlement in explaining mesoscale adult distributions through a combination of laboratory and field studies on a variety of "types" of species (e.g., in terms of life history characteristics, taxonomic position and adult habitat affinity.
