Warm-adapted Red Sea reefs have globally distinct metabolic rates

Coral reefs are in global decline due to climate change, shifting from net heterotrophic to autotrophic systems, impacting carbon cycles and ecosystem resilience. The Red Sea, with some of the warmest waters globally (summer temperatures exceeding 30°C and reaching 38°C) has been proposed as a potential refuge for coral reefs against climate change. However, Red Sea reefs metabolic dynamics are understudied. Here, we measured day and night Net Ecosystem Calcification (NEC) and Net Ecosystem Production (NEP) on two Red Sea reefs using a semi-Lagrangian approach in fall, spring, and during the 2023-2024 summer marine heatwave (11-12°C degree heating weeks). The heatwave strongly altered metabolic rates, leading to a shift toward net heterotrophy and dissolution. Notably, Red Sea reefs exhibited high NEP relative to NEC compared to global averages, functioning as short-term CO₂ sinks and providing insights into future reef performance amid ongoing global warming. 

Presentation Preference: Oral

Primary Presenter: Vincent Saderne, KAUST, King Abdullah University of Science and Technology (vincent.saderne@kaust.edu.sa)

Authors:

Vincent Saderne, Red Sea Research Center, Division of Biological and Environmental Science and Engineering, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia  (vincent.saderne@kaust.edu.sa)

Abel Cortada Galvao, Red Sea Research Center, Division of Biological and Environmental Science and Engineering, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia  (abel.cortadagalvao@kaust.edu.sa)

Ute Langner, Red Sea Research Center, Division of Biological and Environmental Science and Engineering, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia  (ute.langner@kaust.edu.sa)

Matthew Tietbohl, Red Sea Research Center, Division of Biological and Environmental Science and Engineering, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia  (Matthew.tietbohl@kaust.edu.sa)

Walter Rich, Red Sea Research Center, Division of Biological and Environmental Science and Engineering, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia  (Walter.Rich@kaust.edu.sa)

Bram Nieuwenhuis, Red Sea Research Center, Division of Biological and Environmental Science and Engineering, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia  (Bram.Nieuwenhuis@kaust.edu.sa)

Susann Rossbach, Red Sea Global, Riyadh, Saudi Arabia  (susann.rossbach@redseaglobal.com)

David Suggett, KAUST Coral Restoration Initiative (KCRI), King Abdullah University of Science and Technology, Thuwal, Saudi Arabia  (david.suggett@kaust.edu.sa)

Maggie Johnson, Red Sea Research Center, Division of Biological and Environmental Science and Engineering, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia  (maggie.johnson@kaust.edu.sa)