More frequent and intense El Niño events and marine heat waves continue to threaten kelp forests globally. Impacts are likely to be felt particularly strongly in southern California, which constitutes the geographical limit for kelp forests in the US, meaning that kelp populations in this area already experience higher temperatures than kelp populations elsewhere in the country.

This project will investigate the effects of thermal stress at the cellular and organismal levels for six kelp species. The team will assess if there are differences in thermal tolerance between populations and how this might be reflected in their genomes. Kelp with unique genetics/thermal tolerance will be outplanted in the field and monitored for survival and growth.

If thermally tolerant populations of Macrocystis exist in California, they are likely to be found along the San Diego coast due to the local climate. The genomes of any heat-tolerant populations that are identified will be saved in a living seed bank. The results of this project will be of direct use for resource managers trying to restore kelp in areas where it might be exposed to high ocean temperatures due to El Niño events and future marine heat waves.