Skip to main content
Dryad

Data from: Deep oxygen-depleted Red Sea coral reef depressions sustain resistant ecosystems

Klein, Shannon1; Frühe, Larissa1; Parry, Anieka1; Marchese, Fabio1; Nolan, Megan1; Laiolo, Elisa1; Lim, Kah Kheng1; Steckbauer, Alexandra1; Breavington, Jessica1; Hempel, Christopher1; von Krusenstiern, Kate2; van der Zwan, Froukje1; Re, Eleonora1; Alamoudi, Taiba1; Alva Garcia, Jacqueline1; Arossa, Silvia1; Preckler, Carlos1; Rodrigue, Mattie2; Pieribone, Vincent2; Qurban, Mohammad3; Benzoni, Francesca1; Duarte, Carlos1

Research facility: King Abdullah University of Science and Technology
Published Feb 18, 2025 on Dryad. https://doi.org/10.5061/dryad.9w0vt4bq4

Data files

Abstract

Persistent oxygen-depleted zones in the ocean are known primarily from enclosed basins in temperate regions or the open-ocean (including oxygen minimum and limiting zones). However, little is known about the potential for such zones in tropical coastal domains, despite warmer temperatures and complex geomorphological structures in some tropical areas increasing the likelihood of their existence. Here, we report two subsurface oxygen-depleted zones within deep depressions of the Red Sea’s Difaht Farasan—a carbonate platform hosting the world’s third-largest contiguous tropical coral reef system. One zone maintains suboxic oxygen levels (~11-14 µmol kg⁻¹), while the other sustains oxygen levels below detection (<2 µmol kg⁻¹). The suboxic zone shows no fixed nitrogen loss, while the near-anoxic zone hosts anaerobic microbial populations and shows signs of nitrogen loss. We propose that the warm and saline environment of the Red Sea interacts with the semi-enclosed depressions to restrict vertical mixing, limiting oxygen resupply at depth. However, unlike most other oxygen-depleted zones, our deep-sea vehicle surveys demonstrate that these zones support resistant aerobically respiring taxa, indicating an unusual capacity to reduce aerobic oxygen demands at high temperatures (>21°C). Targeted exploration of deep tropical coastal environments is crucial for determining if similar zones exist beyond the Red Sea and understanding their potential responses to climate change.