THERMAL RESISTANCE AND RESILIENCE OF TROPICAL EAST PACIFIC CORAL REEFS DURING THE 2023/2024 EL NIÑO

• Grant number: 25/02078-4
• Support Opportunities: Scholarships abroad - Research Internship - Scientific Initiation
• Start date: May 01, 2025
• End date: August 31, 2025
• Field of knowledge: Physical Sciences and Mathematics - Oceanography - Biological Oceanography
• Principal Investigator: Miguel Mies
• Grantee: Julia Yumi Ibanhez
• Supervisor: Sean Richard Connolly
• Host Institution: Instituto Oceanográfico (IO). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Institution abroad: Smithsonian Institution, Panamá, Panama
• Associated to the scholarship: 24/13329-5 - EL-NIÑO - SOUTHERN OSCILLATION IN 2023-2024: CORAL BLEACHING AND MORTALITY IN THE STATE OF BAHIA, BP.IC

Abstract

Coral reefs, built by scleractinian corals, are critical ecosystems that support 25% of marine species and provide significant socioeconomic benefits, including coastal protection, fishing, and tourism. Despite covering less than 1% of the ocean's surface, reefs contribute approximately $9.8 billion annually. However, they are highly vulnerable to anthropogenic impacts, particularly rising ocean temperatures and acidification caused by increased CO2. Thermal stress disrupts the coral-zooxanthellae symbiosis, leading to bleaching events that have intensified in frequency and severity since 1982. This study focuses on the Eastern Tropical Pacific (ETP), particularly Pacific Panama, where two Pocillopora coral types exhibit differing thermal tolerances due to their symbiotic relationships. Preliminary data indicate that thermally tolerant Durusdinium symbionts are critical for coral resilience but decrease under extreme heat. The ongoing 2024 El Niño has caused severe bleaching, especially in the Gulf of Panama, providing a unique opportunity to study coral bleaching resistance and resilience. The research involves field observations and controlled aquarium experiments to assess the impact of local environmental factors and coral traits on bleaching severity. Coral colonies will be exposed to seven temperature levels, and physiological responses such as photosynthetic efficiency and chlorophyll concentration will be measured. This data will inform a statistical model to predict bleaching intensity, offering insights for conservation strategies to protect coral reefs amid climate change. The study will contribute to understanding coral adaptation and recovery, helping to mitigate future bleaching events.