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Steinberg RK, Ainsworth TD, Moriarty T, Bednarek T, Dafforn KA, Johnston EL. Bleaching Susceptibility and Resistance of Octocorals and Anemones at the World's Southern-Most Coral Reef. Front Physiol 2022; 13:804193. [PMID: 35665222 PMCID: PMC9161773 DOI: 10.3389/fphys.2022.804193] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Accepted: 03/29/2022] [Indexed: 11/16/2022] Open
Abstract
Coral reefs are amongst the most biodiverse ecosystems on earth, and while stony corals create the foundational complexity of these ecosystems, octocorals and anemones contribute significantly to their biodiversity and function. Like stony corals, many octocorals contain Symbiodiniaceae endosymbionts and can bleach when temperatures exceed the species' upper thermal limit. Here, we report octocoral bleaching susceptibility and resistance within the subtropical Lord Howe Island coral reef ecosystem during and after marine heatwaves in 2019. Octocoral and anemone surveys were conducted at multiple reef locations within the Lord Howe Island lagoon during, immediately after, and 7 months after the heatwaves. One octocoral species, Cladiella sp. 1, experienced bleaching and mortality, with some bleached colonies detaching from the reef structure during the heatwave (presumed dead). Those that remained attached to the benthos survived the event and recovered endosymbionts within 7 months of bleaching. Cladiella sp. 1 Symbiodiniaceae density (in cells per µg protein), chlorophyll a and c 2 per µg protein, and photosynthetic efficiency were significantly lower in bleached colonies compared to unbleached colonies, while chlorophyll a and c 2 per symbiont were higher. Interestingly, no other symbiotic octocoral species of the Lord Howe Island lagoonal reef bleached. Unbleached Xenia cf crassa colonies had higher Symbiodiniaceae and chlorophyll densities during the marine heatwave compared to other monitoring intervals, while Cladiella sp. 2 densities did not change substantially through time. Previous work on octocoral bleaching has focused primarily on gorgonian octocorals, while this study provides insight into bleaching variability in other octocoral groups. The study also provides further evidence that octocorals may be generally more resistant to bleaching than stony corals in many, but not all, reef ecosystems. Responses to marine heating events vary and should be assessed on a species by species basis.
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Affiliation(s)
- Rosemary K Steinberg
- Evolution and Ecology Research Centre and Centre for Marine Science and Innovation, School of Biological, Earth, and Environmental Sciences, Faculty of Science, University of New South Wales, Sydney, NSW, Australia
- Sydney Institute of Marine Science, Mosman, NSW, Australia
| | - Tracy D Ainsworth
- Evolution and Ecology Research Centre and Centre for Marine Science and Innovation, School of Biological, Earth, and Environmental Sciences, Faculty of Science, University of New South Wales, Sydney, NSW, Australia
| | - Tess Moriarty
- School of Environmental and Life Sciences, The University of Newcastle, Ourimbah, NSW, Australia
| | - Teresa Bednarek
- Evolution and Ecology Research Centre and Centre for Marine Science and Innovation, School of Biological, Earth, and Environmental Sciences, Faculty of Science, University of New South Wales, Sydney, NSW, Australia
- RUHR Universtad Bouchum, Bouchum, Germany
| | | | - Emma L Johnston
- Evolution and Ecology Research Centre and Centre for Marine Science and Innovation, School of Biological, Earth, and Environmental Sciences, Faculty of Science, University of New South Wales, Sydney, NSW, Australia
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Matsuda SB, Chakravarti LJ, Cunning R, Huffmyer AS, Nelson CE, Gates RD, van Oppen MJH. Temperature-mediated acquisition of rare heterologous symbionts promotes survival of coral larvae under ocean warming. GLOBAL CHANGE BIOLOGY 2022; 28:2006-2025. [PMID: 34957651 PMCID: PMC9303745 DOI: 10.1111/gcb.16057] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Revised: 12/04/2021] [Accepted: 12/07/2021] [Indexed: 06/14/2023]
Abstract
Reef-building corals form nutritional symbioses with endosymbiotic dinoflagellates (Symbiodiniaceae), a relationship that facilitates the ecological success of coral reefs. These symbionts are mostly acquired anew each generation from the environment during early life stages ("horizontal transmission"). Symbiodiniaceae species exhibit trait variation that directly impacts the health and performance of the coral host under ocean warming. Here, we test the capacity for larvae of a horizontally transmitting coral, Acropora tenuis, to establish symbioses with Symbiodiniaceae species in four genera that have varying thermal thresholds (the common symbiont genera, Cladocopium and Durusdinium, and the less common Fugacium and Gerakladium). Over a 2-week period in January 2018, a series of both no-choice and four-way choice experiments were conducted at three temperatures (27, 30, and 31°C). Symbiont acquisition success and cell proliferation were measured in individual larvae. Larvae successfully acquired and maintained symbionts of all four genera in no-choice experiments, and >80% of larvae were infected with at least three genera when offered a four-way choice. Unexpectedly, Gerakladium symbionts increased in dominance over time, and at high temperatures outcompeted Durusdinium, which is regarded as thermally tolerant. Although Fugacium displayed the highest thermal tolerance in culture and reached similar cell densities to the other three symbionts at 31°C, it remained a background symbiont in choice experiments, suggesting host preference for other symbiont species. Larval survivorship at 1 week was highest in larvae associated with Gerakladium and Fugacium symbionts at 27 and 30°C, however at 31°C, mortality was similar for all treatments. We hypothesize that symbionts that are currently rare in corals (e.g., Gerakladium) may become more common and widespread in early life stages under climate warming. Uptake of such symbionts may function as a survival strategy in the wild, and has implications for reef restoration practices that use sexually produced coral stock.
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Affiliation(s)
- Shayle B. Matsuda
- Hawai‘i Institute of Marine BiologyUniversity of Hawai‘i at MānoaKāne‘oheHawai‘iUSA
| | | | - Ross Cunning
- Daniel P. Haerther Center for Conservation and ResearchJohn G. Shedd AquariumChicagoIllinoisUSA
| | - Ariana S. Huffmyer
- Department of Biological SciencesUniversity of Rhode IslandKingstonRhode IslandUSA
| | - Craig E. Nelson
- Daniel K. Inouye Center for Microbial Oceanography: Research and EducationDepartment of Oceanography and Sea Grant College ProgramUniversity of Hawai‘i at MānoaHonoluluHawai‘iUSA
| | - Ruth D. Gates
- Hawai‘i Institute of Marine BiologyUniversity of Hawai‘i at MānoaKāne‘oheHawai‘iUSA
| | - Madeleine J. H. van Oppen
- Australian Institute of Marine ScienceTownsvilleQueenslandAustralia
- School of BioSciencesThe University of MelbourneParkvilleVictoriaAustralia
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Konkes C, Foxwell-Norton K. Science communication and mediatised environmental conflict: A cautionary tale. PUBLIC UNDERSTANDING OF SCIENCE (BRISTOL, ENGLAND) 2021; 30:470-483. [PMID: 33467988 DOI: 10.1177/0963662520985134] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
When Australian physicist, Peter Ridd, lost his tenured position with James Cook University, he was called a 'whistleblower', 'contrarian academic' and 'hero of climate science denial'. In this article, we examine the events surrounding his dismissal to better understand the role of science communication in organised climate change scepticism. We discuss the sophistry of his complaint to locate where and through what processes science communication becomes political communication. We argue that the prominence of scientists and scientific knowledge in debates about climate change locates science, as a social sphere or fifth pillar in Hutchins and Lester's theory of mediatised environmental conflict. In doing so, we provide a model to better understand how science communication can be deployed during politicised debates.
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