Award: OCE-1538626

Most marine invertebrates begin their lives as tiny planktonic larvae that utilize ocean currents to disperse from their release sites. For species that are immobile as adults, this planktonic larval duration (PLD) represents the only time during which organisms are capable of transport between suitable habitats, making this life stage critical for distribution of important marine species. Global ocean changes resulting from climate change can alter the length of this PLD limiting the timeframe in which transport is possible. Larval behavioral responses to the environment may change as the climate changes the ocean, and the physical and hydrodynamic environments in the ocean will shift as well. Together, these impacts of climate change will influence larval dispersal pathways, population connectivity, and range shift velocities for important marine species. This project explored the impacts of environmentally induced biological and behavioral changes in marine invertebrate larvae, using the Olympia oyster as a model. Previous anecdotal observations suggested oyster larvae become "lazy" and stop swimming as a result of ocean acidification. This particular species is economically, ecologically, and culturally important and has been the target of restoration efforts along the US west coast. We used a novel experimental approach to rear Olympia oyster larvae under interacting gradients of temperature, salinity, and ocean acidification, which are among the most important variables predicted to change as a result of climate shifts. We then used this data to model growth rate and duration of Olympia oyster larvae and predict the suitability of habitats for larval survival in the Salish Sea, a marginal sea located in British Columbia and Washington State. Our modeling showed that present temperature and salinity conditions in the Salish Sea are actually suboptimal for the growth and survival of larvae of Olympia oysters and these larvae might actually benefit from warming since the Salish Sea is near their present northern range edge. Larval growth and survival of these oysters tended to be relatively resilient to ocean acidification but results on larval behavioral responses to acidification varied and may be family dependent. We are working in collaboration with oceanographers the to integrate these results into a dispersal model to test the effects of climate-induced changes to larval growth, PLDs, and behavior on larval dispersal potential and population connectivity. Our initial modeled scenarios suggest that Olympia oyster larval durations will greatly decrease in the future, leading to changes in dispersal potential, dependent on regional hydrodynamic processes. We also explored the relationships between environmental factors and larval vertical distributions of the Olympia oyster through strategic larval sampling in Fidalgo Bay, a shallow, tidally flushed bay in the Salish Sea. Similar to our Salish Sea dispersal model predictions, sampling in Fidalgo Bay demonstrated the importance of larval vertical distribution behavior and underscored the importance of integrating local hydrodynamics into predictions of bivalve larval transport. The project tightly coupled research and education of master's and undergraduate students at Western Washington University (WWU), a primarily undergraduate university. Mentorship was a core value of the project; the principal investigators (PI) worked closely with all students involved and built connections between students at all levels. Two students earned their master's degrees by participating in this project. One of these students has gone on to a doctoral program and the other is a State-sponsored researcher in a field closely related to the project scope. Participating undergraduate researchers included five WWU students, five NSF-Research Experience for Undergraduates interns from Minnesota, Wisconsin, New York, and Puerto Rico, and one undergraduate volunteer from California. The project provided direct research training for students from underrepresented groups, including at least six students who identify with racial/ethnic groups that are underserved in STEM and multiple first-generation college students. Additionally, we coupled student research with public outreach through a partnership between a summer REU site-program and a project-sponsored undergraduate art internship aimed at developing artwork to communicate climate change. This collaboration between students, informed by PI-led workshops on climate change, visualizations in science, and communication, produced featured artwork displayed at a local arts festival that regularly attracts an estimated 90,000 visitors. Last Modified: 05/03/2021 Submitted by: Shawn M Arellano