ABSTRACT

Marine heatwaves (MHWs) ? prolonged periods of unusually warm surface seawater temperatures - have increased in intensity and frequency in US coastal waters. Recent MHWs on the US West Coast have resulted in changes in species distributions, loss of biodiversity and closed fisheries due to harmful algal blooms. As the frequency of MHWs increase, these events will continue to impact natural marine ecosystems and important resources from the ocean (e.g., fishing and aquaculture). The goal of this project is to better understand how MHWs will affect coastal marine communities like kelp forests. A key missing piece of information is how early life-history stages, the stages that disperse and maintain healthy populations of marine organisms, fare in response to these anomalously high ocean temperatures. This project is investigating the response and resilience to MHW stress in embryos and larvae of two key marine invertebrates, the red and purple sea urchins that inhabit the kelp forests of coastal California. The red urchin is a valuable fishery (the roe is sold as uni) and data from this project is contributing to the management of this natural resource. Lastly, the project is training early career researchers, undergraduate and graduate students with a focus on broadening participation in the fields of science and technology. The broader impacts are providing research experiences and mentoring to under-represented undergraduates at UC Santa Barbara, a Hispanic-Serving Institution since 2015. The project directly supports the PhD dissertation research of three women Ph.D. graduate students from under-represented groups.

This project aims to understand the consequences of anomalously high temperatures during MHW events on reproduction and early development of marine organisms. In the coastal California system, marine invertebrates of the kelp forest ecosystem are reproductive when MHWs tend to occur and intensify. The major goal is to examine how maternal and paternal effects, that play out in a MHW context, influence the thermal tolerance of early developmental stages of two sea urchin species from the temperate kelp forest communities of coastal California, the purple (Strongylocentrotus purpuratus) and red (Mesocentrotus franciscanus) sea urchins, the latter being an important wild fisheries species. This project is addressing climate-change relevant aspects of larval ecology and is examining how phenotypic plasticity contributes to adaptive capacity of marine organisms. A series of traits are being assessed for each species: (1) fertilization kinetics, (2) successful developmental progression, (3) thermal tolerance (via thermal tolerance trials and biochemical indices of thermal stress), and (4) parental effects. Gene expression using RNA sequencing is capturing the influence of maternal effects to address whether females that experience MHW temperatures in situ during gametogenesis produce progeny with greater thermal tolerance via changes of the larval transcriptome.

This project is jointly funded by the Biological Oceanography and Integrative Ecological Physiology Programs.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

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