A coupled hydrodynamic-larval transport model for assessing source-sink recruitment dynamics in estuarine habitats

Date of Completion

January 2005


Biology, Oceanography




For many benthic invertebrates, a free-swimming larval stage links a reproductively active adult to the successful establishment of a new sessile individual or colony. Larvae range from those that are long lived and dispersed regionally to those that are short lived and dispersed more locally. For those species with a short lived larval stage, the success at colonizing a suitable habitat may be strongly influenced by the pattern of tidally induced water movement and the availability of reproductively active adults upstream of settlement sites. ^ This study combines physics and biology into an integrated model that estimates the relative magnitude of delivery of benthic invertebrate larvae over spatial and temporal scales relevant to the organisms under study. A hydrodynamic model was integrated with a survey that defined adult habitats and hence source areas for larval release. Biological parameters, such as life history data (e.g. timing of larval release and larval lifetime), were also incorporated into the model. The combined hydrodynamic-larval transport model was then used to address ecological questions concerning larval sources and sinks in an estuarine embayment located in southeastern New England. ^ The model results were used to guide and interpret field sampling at appropriate locations and times. For the colonial ascidians inhabiting the study area, a comparison of the model predictions to the results from automated time-series invertebrate recruitment sampling equipment indicated some source habitats contributed a greater supply of larvae to the water column than others. ^