Award: OCE-1801335

This project was a rapid response to the Category 5 hurricanes that impacted St. John, US Virgin Islands, in September 2017. The project leveraged 31 years of research focused on the long-term changes in the reefs of St. John, specifically to evaluate the effects of two storms that are without precedent on the scale of human memory. The legacy research captured the effects of three previous storms (Hurricanes Hugo in 1989, and Luis and Marilyn in 1995) on the same reefs, and therefore it was possible to place the destruction of 2017 in an historic context. Funding from this award supported surveys of reef damage within two months of the impacts of the storm, and over the following 12 months, a follow-up survey in the summer of 2018, and analysis of the data and samples obtained. Together, the results have made three contributions to the understanding of coral reefs, the threats they face from storms, and the prognosis for their future. First, in contrast to the expectation that storms pose risks of catastrophic damage to coral reefs, the stony corals on the present reefs were resilient to storms. This is not good news, however, as this resilience has come through adversity and the death of corals over 30 years. So much coral has died since 1987 that there was relatively little left to be lost when Hurricanes Irma and Maria arrived in September 2017. There is a salutary message in this discovery, for conservation biologists often seek to manage reefs for high resilience, yet St. John shows how this outcome can be obtained through characteristics that are undesirable (i.e., little coral). Second, through the fortuitous deployment of an underwater light meter that survived the hurricanes, it has been possible to show the multi-week impacts of storms on underwater light regimes. These events were so large that they temporarily turned these coral reefs into a light-impaired habitat with negative implications on the organisms dependent on light for food. Finally, by reconstructing the effects of the storms on the sizes and mortality of colonies of the common coral, Orbicella annularis, it has been possible to reveal the hidden effects on coral populations. While the percentage cover of this species was unaffected by the storms, reductions in the sizes of colonies moved them to a smaller size range in which the risks of dying are high, thus depleting the population of unique individuals. Overall, these storms had only minor effects on the cover of stony corals on reefs that already had been depleted of coral over 30 years, and these effects are unlikely alter future coral cover. By removing unique coral genotypes, however, the storms may have built in a delayed effect to the coral populations, such that the future small populations could show enhance susceptibility to disturbances such as diseases. Major hurricanes provide unwelcomed disturbances affecting humans and nature in catastrophic ways. They also provide opportunities through natural experiments to better understand processes shaping the natural world. But completion of the present research also provided unique opportunities for early students and scientists to develop skills in a real world situation that has no classroom parallel. The post-storms surveys were completed from the R/V Walton Smith, and the team brought personnel together from universities and the US National Park Service. Graduate students from California State University, Northridge, learned from hands-on experience to be better biologist, ambassadors of science, and humanitarian visitors in an area affected by a major natural disaster. These experiences were expanded through 2018 as the science progressed, team members reflected on their experiences, and participants brought their contributions to fruition and carried their experiences to high schools through classroom presentation. Overall, the experience of conducting research on the ecological impacts of a natural disaster, effectively while the disaster was still unfolding, has done much to encourage a small cohort of students to pursue STEM careers. Last Modified: 05/03/2019 Submitted by: Peter J Edmunds