Thermotolerant coral–algal mutualisms maintain high rates of nutrient transfer while exposed to heat stress
Date
2023-09-20
Journal Title
Journal ISSN
Volume Title
Publisher
Proceedings of the Royal Society B: Biological Sciences
Abstract
Symbiotic mutualisms are essential to ecosystems and numerous species across the tree of life. For reef-building corals, the benefits of their association with endosymbiotic dinoflagellates differ within and across taxa, and nutrient exchange between these partners is influenced by environmental conditions. Furthermore, it is widely assumed that corals associated with symbionts in the genus Durusdinium tolerate high thermal stress at the expense of lower nutrient exchange to support coral growth. We traced both inorganic carbon (H13CO3–) and nitrate (15NO3–) uptake by divergent symbiont species and quantified nutrient transfer to the host coral under normal temperatures as well as in colonies exposed to high thermal stress. Colonies representative of diverse coral taxa associated with Durusdinium trenchii or Cladocopium spp. exhibited similar nutrient exchange under ambient conditions. By contrast, heat-exposed colonies with D. trenchii experienced less physiological stress than conspecifics with Cladocopium spp. while high carbon assimilation and nutrient transfer to the host was maintained. This discovery differs from the prevailing notion that these mutualisms inevitably suffer trade-offs in physiological performance. These findings emphasize that many host–symbiont combinations adapted to high-temperature equatorial environments are high-functioning mutualisms; and why their increased prevalence is likely to be important to the future productivity and stability of coral reef ecosystems.
Description
This article was originally published in Proceedings of the Royal Society B: Biological Sciences. The version of record is available at: https://doi.org/10.1098/rspb.2023.1403. © 2023 The Authors.
Keywords
coral reefs, physiological trade-offs, global warming, mutualistic symbiosis, nutrient cycling
Citation
Kemp, Dustin W., Kenneth D. Hoadley, Allison M. Lewis, Drew C. Wham, Robin T. Smith, Mark E. Warner, and Todd C. LaJeunesse. “Thermotolerant Coral–Algal Mutualisms Maintain High Rates of Nutrient Transfer While Exposed to Heat Stress.” Proceedings of the Royal Society B: Biological Sciences 290, no. 2007 (September 27, 2023): 20231403. https://doi.org/10.1098/rspb.2023.1403.