UC Irvine

This thesis investigates the physical processes that govern the transport and environmental history of marine invertebrates during their larval stage, focusing on the role of wind-driven flow and freshwater plumes. Additionally, this work examines how release location and swimming behavior modifies the path and environmental history of a larval particle. The research was conducted by using Regional Ocean Modeling System (ROMS) and a particle-tracking code to estimate the transport of larval-stage invertebrates and their environmental history over the larval duration period (particle paths) in parameters such as temperature, salinity and phytoplankton concentration. Results indicate that swimming particles are retained closer to shore and to their release location compared to passive particles (no swimming behavior). The freshwater plume affects alongshore dispersal of particles released to the south of the Columbia River during downwelling periods and weak upwelling periods, and particles released to the north of the river during downwelling periods. Furthermore, wind-driven circulation can influence the environmental exposure of larval stage marine invertebrates. Particles north of the Columbia River mouth saw greater variation in temperature and salinity, and higher phytoplankton concentration as upwelling index increased. As upwelling intensity increases, southern particles experience lower average temperature, higher salinity, and higher phytoplankton concentration conditions (however, lower phytoplankton concentrations than northern particles). This work suggests that wind-driven circulation and freshwater plumes can play an important role in the distribution and environmental history of larval stage marine invertebrates and this could influence their future persistence along the U.S. West Coast.