Survivorship and Bleaching Prevalence of Nursery-Grown Massive Stony Corals in Southeast Florida
Abstract
Coral cover on Florida’s reefs has severely declined due to anthropogenic stressors. A major impact on corals is thermal bleaching, where corals expel their endosymbiotic microalgae, leaving them vulnerable to mortality. Some coral species are more resilient to thermal bleaching and thus may be prime candidates to support coral reef restoration. This study examines post-bleaching survivorship of massive stony coral species in Nova Southeastern University's offshore nursery to identify which species to include in future restoration efforts. In September 2022, 172 fragments (<3cm dia) from six massive species were secured on cement pucks and deployed to mid-water PVC trees in the nursery. Over a 14- month period, the survival and bleaching prevalence of each species were recorded during four monitoring time points. After 14 months in the nursery, total fragment survivorship was 80%, with Pseudodiploria strigosa experiencing the highest survival (100%) and Orbicella favelota experiencing the lowest (61%). Water temperature was also recorded and the average daily temperature was above the bleaching threshold (>30℃) for 22 days in August 2023. The bleaching prevalence for all fragments was approximately 47% during August 2023, with three species experiencing 100% bleaching. However, almost all fragments recovered their symbionts by December 2023 and the 20% mortality could not be attributed to bleaching. Nevertheless, ocean temperature anomalies are predicted to become more frequent and severe, with potentially compounding impacts on nursery-reared corals. The findings from this study suggest that rearing massive fragments in an offshore nursery is successful even during bleaching events.
Faculty Sponsors
Dr. David Gilliam, Casey Harris
Project Type
Event
Location
Alvin Sherman Library
Start Date
4-3-2024 12:30 PM
End Date
4-4-2024 1:30 PM
Survivorship and Bleaching Prevalence of Nursery-Grown Massive Stony Corals in Southeast Florida
Alvin Sherman Library
Coral cover on Florida’s reefs has severely declined due to anthropogenic stressors. A major impact on corals is thermal bleaching, where corals expel their endosymbiotic microalgae, leaving them vulnerable to mortality. Some coral species are more resilient to thermal bleaching and thus may be prime candidates to support coral reef restoration. This study examines post-bleaching survivorship of massive stony coral species in Nova Southeastern University's offshore nursery to identify which species to include in future restoration efforts. In September 2022, 172 fragments (<3cm >dia) from six massive species were secured on cement pucks and deployed to mid-water PVC trees in the nursery. Over a 14- month period, the survival and bleaching prevalence of each species were recorded during four monitoring time points. After 14 months in the nursery, total fragment survivorship was 80%, with Pseudodiploria strigosa experiencing the highest survival (100%) and Orbicella favelota experiencing the lowest (61%). Water temperature was also recorded and the average daily temperature was above the bleaching threshold (>30℃) for 22 days in August 2023. The bleaching prevalence for all fragments was approximately 47% during August 2023, with three species experiencing 100% bleaching. However, almost all fragments recovered their symbionts by December 2023 and the 20% mortality could not be attributed to bleaching. Nevertheless, ocean temperature anomalies are predicted to become more frequent and severe, with potentially compounding impacts on nursery-reared corals. The findings from this study suggest that rearing massive fragments in an offshore nursery is successful even during bleaching events.
