Evidence of acclimatization or adaptation in Hawaiian corals to higher ocean temperatures
Ocean temperatures have been accelerating at an alarming rate mainly due to anthropogenic fossil fuel emissions. This has led to an increase in the severity and duration of coral bleaching events. Predicted projections for the state of reefs do not take into account the rates of adaptation or acclim...
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| Format: | Article |
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PeerJ Inc.
2018-08-01
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| Online Access: | https://peerj.com/articles/5347.pdf |
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| author | Steve L. Coles Keisha D. Bahr Ku’ulei S. Rodgers Stacie L. May Ashley E. McGowan Anita Tsang Josh Bumgarner Ji Hoon Han |
| author_facet | Steve L. Coles Keisha D. Bahr Ku’ulei S. Rodgers Stacie L. May Ashley E. McGowan Anita Tsang Josh Bumgarner Ji Hoon Han |
| author_sort | Steve L. Coles |
| collection | DOAJ |
| description | Ocean temperatures have been accelerating at an alarming rate mainly due to anthropogenic fossil fuel emissions. This has led to an increase in the severity and duration of coral bleaching events. Predicted projections for the state of reefs do not take into account the rates of adaptation or acclimatization of corals as these have not as yet been fully documented. To determine any possible changes in thermal tolerances, manipulative experiments were conducted to precisely replicate the initial, pivotal research defining threshold temperatures of corals nearly five decades ago. Statistically higher calcification rates, survivorship, and lower mortality were observed in Montipora capitata, Pocillopora damicornis, and Lobactis scutaria in the present study at 31 °C compared to the original 1970 findings. First whole colony mortality was also observed to occur sooner in 1970 than in 2017 in M. capitata (3 d vs. 15 d respectively), L. scutaria (3 d vs. 17 d), and in P. damicornis (3 d vs. 13 d). Additionally, bleaching occurred sooner in 1970 compared to the 2017 experiment across species. Irradiance was an important factor during the recovery period for mortality but did not significantly alter calcification. Mortality was decreased by 17% with a 50% reduction in irradiance during the recovery period. These findings provide the first evidence of coral acclimatization or adaptation to increasing ocean temperatures for corals collected from the same location and using close replication of the experiment conducted nearly 50 years earlier. An important factor in this increased resistance to elevated temperature may be related to removal of the discharge of treated sewage into Kāne‘ohe Bay and resulting decrease in nitrification and eutrophication. However, this level of increased temperature tolerance may not be occurring rapidly enough to escape the projected increased intensity of bleaching events, as evidenced by the recent 2014 and 2015 high coral mortality in Hawai‘i (34%) and in the tropics worldwide. |
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| institution | Directory Open Access Journal |
| issn | 2167-8359 |
| language | English |
| last_indexed | 2024-03-09T07:22:18Z |
| publishDate | 2018-08-01 |
| publisher | PeerJ Inc. |
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| spelling | doaj.art-cfdc75c3e41b485d81dd10d11665a1bd2023-12-03T07:15:16ZengPeerJ Inc.PeerJ2167-83592018-08-016e534710.7717/peerj.5347Evidence of acclimatization or adaptation in Hawaiian corals to higher ocean temperaturesSteve L. Coles0Keisha D. Bahr1Ku’ulei S. Rodgers2Stacie L. May3Ashley E. McGowan4Anita Tsang5Josh Bumgarner6Ji Hoon Han7Bernice Pauahi Bishop Museum, Department of Natural Sciences, Honolulu, Hawai’i, USAUniversity of Hawai’i at Mānoa, Hawai’i Institute of Marine Biology, Kāne’ohe, Hawai’i, USAUniversity of Hawai’i at Mānoa, Hawai’i Institute of Marine Biology, Kāne’ohe, Hawai’i, USAUniversity of Hawai’i at Mānoa, Hawai’i Institute of Marine Biology, Kāne’ohe, Hawai’i, USAUniversity of Hawai’i at Mānoa, Hawai’i Institute of Marine Biology, Kāne’ohe, Hawai’i, USAUniversity of Hawai’i at Mānoa, Hawai’i Institute of Marine Biology, Kāne’ohe, Hawai’i, USAUniversity of Hawai’i at Mānoa, Hawai’i Institute of Marine Biology, Kāne’ohe, Hawai’i, USAUniversity of Hawai’i at Mānoa, Hawai’i Institute of Marine Biology, Kāne’ohe, Hawai’i, USAOcean temperatures have been accelerating at an alarming rate mainly due to anthropogenic fossil fuel emissions. This has led to an increase in the severity and duration of coral bleaching events. Predicted projections for the state of reefs do not take into account the rates of adaptation or acclimatization of corals as these have not as yet been fully documented. To determine any possible changes in thermal tolerances, manipulative experiments were conducted to precisely replicate the initial, pivotal research defining threshold temperatures of corals nearly five decades ago. Statistically higher calcification rates, survivorship, and lower mortality were observed in Montipora capitata, Pocillopora damicornis, and Lobactis scutaria in the present study at 31 °C compared to the original 1970 findings. First whole colony mortality was also observed to occur sooner in 1970 than in 2017 in M. capitata (3 d vs. 15 d respectively), L. scutaria (3 d vs. 17 d), and in P. damicornis (3 d vs. 13 d). Additionally, bleaching occurred sooner in 1970 compared to the 2017 experiment across species. Irradiance was an important factor during the recovery period for mortality but did not significantly alter calcification. Mortality was decreased by 17% with a 50% reduction in irradiance during the recovery period. These findings provide the first evidence of coral acclimatization or adaptation to increasing ocean temperatures for corals collected from the same location and using close replication of the experiment conducted nearly 50 years earlier. An important factor in this increased resistance to elevated temperature may be related to removal of the discharge of treated sewage into Kāne‘ohe Bay and resulting decrease in nitrification and eutrophication. However, this level of increased temperature tolerance may not be occurring rapidly enough to escape the projected increased intensity of bleaching events, as evidenced by the recent 2014 and 2015 high coral mortality in Hawai‘i (34%) and in the tropics worldwide.https://peerj.com/articles/5347.pdfClimate changeCoral reefsAdaptationBleachingOcean warmingAcclimatization |
| spellingShingle | Steve L. Coles Keisha D. Bahr Ku’ulei S. Rodgers Stacie L. May Ashley E. McGowan Anita Tsang Josh Bumgarner Ji Hoon Han Evidence of acclimatization or adaptation in Hawaiian corals to higher ocean temperatures PeerJ Climate change Coral reefs Adaptation Bleaching Ocean warming Acclimatization |
| title | Evidence of acclimatization or adaptation in Hawaiian corals to higher ocean temperatures |
| title_full | Evidence of acclimatization or adaptation in Hawaiian corals to higher ocean temperatures |
| title_fullStr | Evidence of acclimatization or adaptation in Hawaiian corals to higher ocean temperatures |
| title_full_unstemmed | Evidence of acclimatization or adaptation in Hawaiian corals to higher ocean temperatures |
| title_short | Evidence of acclimatization or adaptation in Hawaiian corals to higher ocean temperatures |
| title_sort | evidence of acclimatization or adaptation in hawaiian corals to higher ocean temperatures |
| topic | Climate change Coral reefs Adaptation Bleaching Ocean warming Acclimatization |
| url | https://peerj.com/articles/5347.pdf |
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