Differential susceptibility of reef-building corals to deoxygenation reveals remarkable hypoxia tolerance.

Maggie D Johnson, Sara D Swaminathan, Emily N Nixon, Valerie J Paul, Andrew H Altieri

Research output: Contribution to journalArticlepeer-review

20 Scopus citations

Abstract

Ocean deoxygenation threatens the persistence of coastal ecosystems worldwide. Despite an increasing awareness that coastal deoxygenation impacts tropical habitats, there remains a paucity of empirical data on the effects of oxygen limitation on reef-building corals. To address this knowledge gap, we conducted laboratory experiments with ecologically important Caribbean corals Acropora cervicornis and Orbicella faveolata. We tested the effects of continuous exposure to conditions ranging from extreme deoxygenation to normoxia (~ 1.0 to 6.25 mg L$^{-1}$ dissolved oxygen) on coral bleaching, photophysiology, and survival. Coral species demonstrated markedly different temporal resistance to deoxygenation, and within a species there were minimal genotype-specific treatment effects. Acropora cervicornis suffered tissue loss and mortality within a day of exposure to severe deoxygenation (~ 1.0 mg L$^{-1}$), whereas O. faveolata remained unaffected after 11 days of continuous exposure to 1.0 mg L$^{-1}$. Intermediate deoxygenation treatments (~ 2.25 mg L$^{-1}$, ~ 4.25 mg L$^{-1}$) elicited minimal responses in both species, indicating a low oxygen threshold for coral mortality and coral resilience to oxygen concentrations that are lethal for other marine organisms. These findings demonstrate the potential for variability in species-specific hypoxia thresholds, which has important implications for our ability to predict how coral reefs may be affected as ocean deoxygenation intensifies. With deoxygenation emerging as a critical threat to tropical habitats, there is an urgent need to incorporate deoxygenation into coral reef research, management, and action plans to facilitate better stewardship of coral reefs in an era of rapid environmental change.
Original languageEnglish (US)
JournalScientific reports
Volume11
Issue number1
DOIs
StatePublished - Dec 1 2021

Bibliographical note

KAUST Repository Item: Exported on 2021-12-14
Acknowledgements: We thank W. Allen, S. Reed, J. Sneed, B. Ushijima, H. Sweat, J. Houk, D. Branson, and the staff at SMS for logistical and facilities support; E. Bartels, S. Hamlyn and the staff at Mote Marine Laboratory in Summerland Key for providing corals and nursery data; T. Vekich, A. Carreiro, E. Carlton, A. Guariniello, D. Harnish, C. Hiaasen, W. Ferrell, M. Orense, and H. Kaminksi for lab assistance; I. Kuffner, A. Bruckner, T. Moore, J. Hunt, K. Puglise, and L. Shaver for feedback and advice on experimental design. Research was conducted under permit FKNMS-2018-129 to AA from the Office of National Marine Sanctuaries. This research was funded by an award from the National Oceanic and Atmospheric Administration’s National Centers for Coastal Ocean Science Competitive Research Program to AA, MJ, and VP (NA18NOS4780170) through the University of Florida. MJ was funded by postdoctoral fellow awards from the Smithsonian Institution’s Marine Global Earth Observatory (MarineGEO), the Smithsonian Marine Station, and Woods Hole Oceanographic Institution. This material is based on work supported by the National Science Foundation Graduate Research Fellowship under Grant No. DGE-1842473. This is contribution 259 from the Coastal Hypoxia Research Program, 93 from the Smithsonian’s MarineGEO and Tennenbaum Marine Observatories Network, and 1167 from the Smithsonian Marine Station at Fort Pierce.

ASJC Scopus subject areas

  • General

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