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McCarthy OS, Winston Pomeroy M, Smith JE. Corals that survive repeated thermal stress show signs of selection and acclimatization. PLoS One 2024; 19:e0303779. [PMID: 39083457 PMCID: PMC11290665 DOI: 10.1371/journal.pone.0303779] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2024] [Accepted: 05/01/2024] [Indexed: 08/02/2024] Open
Abstract
Climate change is transforming coral reefs by increasing the frequency and intensity of marine heatwaves, often leading to coral bleaching and mortality. Coral communities have demonstrated modest increases in thermal tolerance following repeated exposure to moderate heat stress, but it is unclear whether these shifts represent acclimatization of individual colonies or mortality of thermally susceptible individuals. For corals that survive repeated bleaching events, it is important to understand how past bleaching responses impact future growth potential. Here, we track the bleaching responses of 1,832 corals in leeward Maui through multiple marine heatwaves and document patterns of coral growth and survivorship over a seven-year period. While we find limited evidence of acclimatization at population scales, we document reduced bleaching over time in specific individuals that is indicative of acclimatization, primarily in the stress-tolerant taxa Porites lobata. For corals that survived both bleaching events, we find no relationship between bleaching response and coral growth in three of four taxa studied. This decoupling suggests that coral survivorship is a better indicator of future growth than is a coral's bleaching history. Based on these results, we recommend restoration practitioners in Hawai'i focus on colonies of Porites and Montipora with a proven track-record of growth and survivorship, rather than devote resources toward identifying and cultivating bleaching-resistant phenotypes in the lab. Survivorship followed a latitudinal thermal stress gradient, but because this gradient was small, it is likely that local environmental factors also drove differences in coral performance between sites. Efforts to reduce human impacts at low performing sites would likely improve coral survivorship in the future.
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Affiliation(s)
- Orion S. McCarthy
- Scripps Institution of Oceanography, Center for Marine Biodiversity and Conservation, University of California San Diego, La Jolla, California, United States of America
| | - Morgan Winston Pomeroy
- School of Geographical Sciences and Urban Planning, Arizona State University, Tempe, Arizona, United States of America
- Center for Global Discovery and Conservation Science, Arizona State University, Hilo, Hawai‘i, United States of America
| | - Jennifer E. Smith
- Scripps Institution of Oceanography, Center for Marine Biodiversity and Conservation, University of California San Diego, La Jolla, California, United States of America
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2
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Perelman JN, Tanaka KR, Smith JN, Barkley HC, Powell BS. Subsurface temperature estimates from a Regional Ocean Modelling System (ROMS) reanalysis provide accurate coral heat stress indices across the Main Hawaiian Islands. Sci Rep 2024; 14:6620. [PMID: 38503796 PMCID: PMC10951325 DOI: 10.1038/s41598-024-56865-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2023] [Accepted: 03/12/2024] [Indexed: 03/21/2024] Open
Abstract
As ocean temperatures continue to rise, coral bleaching events around the globe are becoming stronger and more frequent. High-resolution temperature data is therefore critical for monitoring reef conditions to identify indicators of heat stress. Satellite and in situ measurements have historically been relied upon to study the thermal tolerances of coral reefs, but these data are quite limited in their spatial and temporal coverage. Ocean circulation models could provide an alternative or complement to these limited data, but a thorough evaluation against in situ measurements has yet to be conducted in any Pacific Islands region. Here we compared subsurface temperature measurements around the nearshore Main Hawaiian Islands (MHI) from 2010 to 2017 with temperature predictions from an operational Regional Ocean Modeling System (ROMS) to evaluate the potential utility of this model as a tool for coral reef management. We found that overall, the ROMS reanalysis presents accurate subsurface temperature predictions across the nearshore MHI region and captures a significant amount of observed temperature variability. The model recreates several temperature metrics used to identify coral heat stress, including predicting the 2014 and 2015 bleaching events around Hawai'i during the summer and fall months of those years. The MHI ROMS simulation proves to be a useful tool for coral reef management in the absence of, or to supplement, subsurface and satellite measurements across Hawai'i and likely for other Pacific Island regions.
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Affiliation(s)
- Jessica N Perelman
- Cooperative Institute for Marine and Atmospheric Research, University of Hawaii, 1000 Pope Road, Honolulu, HI, 96822, USA.
- Pacific Islands Fisheries Science Center, National Marine Fisheries Service, 1845 Wasp Boulevard, Honolulu, HI, 96818, USA.
| | - Kisei R Tanaka
- Pacific Islands Fisheries Science Center, National Marine Fisheries Service, 1845 Wasp Boulevard, Honolulu, HI, 96818, USA
| | - Joy N Smith
- Cooperative Institute for Marine and Atmospheric Research, University of Hawaii, 1000 Pope Road, Honolulu, HI, 96822, USA
- Pacific Islands Fisheries Science Center, National Marine Fisheries Service, 1845 Wasp Boulevard, Honolulu, HI, 96818, USA
| | - Hannah C Barkley
- Pacific Islands Fisheries Science Center, National Marine Fisheries Service, 1845 Wasp Boulevard, Honolulu, HI, 96818, USA
| | - Brian S Powell
- Department of Oceanography, University of Hawai'i at Mānoa, Honolulu, HI, 96822, USA
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3
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Khen A, Wall CB, Smith JE. Standardization of in situ coral bleaching measurements highlights the variability in responses across genera, morphologies, and regions. PeerJ 2023; 11:e16100. [PMID: 37810774 PMCID: PMC10552771 DOI: 10.7717/peerj.16100] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Accepted: 08/25/2023] [Indexed: 10/10/2023] Open
Abstract
Marine heatwaves and regional coral bleaching events have become more frequent and severe across the world's oceans over the last several decades due to global climate change. Observational studies have documented spatiotemporal variation in the responses of reef-building corals to thermal stress within and among taxa across geographic scales. Although many tools exist for predicting, detecting, and quantifying coral bleaching, it remains difficult to compare bleaching severity (e.g., percent cover of bleached surface areas) among studies and across species or regions. For this review, we compiled over 2,100 in situ coral bleaching observations representing 87 reef-building coral genera and 250 species of common morphological groups from a total of 74 peer-reviewed scientific articles, encompassing three broad geographic regions (Atlantic, Indian, and Pacific Oceans). While bleaching severity was found to vary by region, genus, and morphology, we found that both genera and morphologies responded differently to thermal stress across regions. These patterns were complicated by (i) inconsistent methods and response metrics across studies; (ii) differing ecological scales of observations (i.e., individual colony-level vs. population or community-level); and (iii) temporal variability in surveys with respect to the onset of thermal stress and the chronology of bleaching episodes. To improve cross-study comparisons, we recommend that future surveys prioritize measuring bleaching in the same individual coral colonies over time and incorporate the severity and timing of warming into their analyses. By reevaluating and standardizing the ways in which coral bleaching is quantified, researchers will be able to track responses to marine heatwaves with increased rigor, precision, and accuracy.
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Affiliation(s)
- Adi Khen
- Center for Marine Biodiversity and Conservation, Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA, United States of America
| | - Christopher B. Wall
- Division of Biological Sciences, University of California San Diego, La Jolla, CA, United States of America
| | - Jennifer E. Smith
- Center for Marine Biodiversity and Conservation, Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA, United States of America
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4
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Price JT, McLachlan RH, Jury CP, Toonen RJ, Wilkins MJ, Grottoli AG. Long-term coral microbial community acclimatization is associated with coral survival in a changing climate. PLoS One 2023; 18:e0291503. [PMID: 37738222 PMCID: PMC10516427 DOI: 10.1371/journal.pone.0291503] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Accepted: 08/30/2023] [Indexed: 09/24/2023] Open
Abstract
The plasticity of some coral-associated microbial communities under stressors like warming and ocean acidification suggests the microbiome has a role in the acclimatization of corals to future ocean conditions. Here, we evaluated the acclimatization potential of coral-associated microbial communities of four Hawaiian coral species (Porites compressa, Porites lobata, Montipora capitata, and Pocillopora acuta) over 22-month mesocosm experiment. The corals were exposed to one of four treatments: control, ocean acidification, ocean warming, or combined future ocean conditions. Over the 22-month study, 33-67% of corals died or experienced a loss of most live tissue coverage in the ocean warming and future ocean treatments while only 0-10% died in the ocean acidification and control. Among the survivors, coral-associated microbial communities responded to the chronic future ocean treatment in one of two ways: (1) microbial communities differed between the control and future ocean treatment, suggesting the potential capacity for acclimatization, or (2) microbial communities did not significantly differ between the control and future ocean treatment. The first strategy was observed in both Porites species and was associated with higher survivorship compared to M. capitata and P. acuta which exhibited the second strategy. Interestingly, the microbial community responses to chronic stressors were independent of coral physiology. These findings indicate acclimatization of microbial communities may confer resilience in some species of corals to chronic warming associated with climate change. However, M. capitata genets that survived the future ocean treatment hosted significantly different microbial communities from those that died, suggesting the microbial communities of the survivors conferred some resilience. Thus, even among coral species with inflexible microbial communities, some individuals may already be tolerant to future ocean conditions. These findings suggest that coral-associated microbial communities could play an important role in the persistence of some corals and underlie climate change-driven shifts in coral community composition.
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Affiliation(s)
- James T. Price
- School of Earth Sciences, The Ohio State University, Columbus, Ohio, United States of America
| | - Rowan H. McLachlan
- School of Earth Sciences, The Ohio State University, Columbus, Ohio, United States of America
- Department of Microbiology, Oregon State University, Corvallis, Oregon, United States of America
| | - Christopher P. Jury
- Hawai‘i Institute of Marine Biology, School of Ocean and Earth Science and Technology, University of Hawai‘i at Mānoa, Honolulu, Hawai‘i, United States of America
| | - Robert J. Toonen
- Hawai‘i Institute of Marine Biology, School of Ocean and Earth Science and Technology, University of Hawai‘i at Mānoa, Honolulu, Hawai‘i, United States of America
| | - Michael J. Wilkins
- Department of Soil and Crop Sciences, Colorado State University, Fort Collins, Colorado, United States of America
| | - Andréa G. Grottoli
- School of Earth Sciences, The Ohio State University, Columbus, Ohio, United States of America
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5
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Ward RJ, Cox TE, Faucci A, La Valle FF, Philippoff J, Schaefer JLB, Ware IM, Knope ML. Spatial variation and antecedent sea surface temperature conditions influence Hawaiian intertidal community structure. PLoS One 2023; 18:e0286136. [PMID: 37267286 DOI: 10.1371/journal.pone.0286136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2022] [Accepted: 05/09/2023] [Indexed: 06/04/2023] Open
Abstract
Global sea surface temperatures (SSTs) are increasing, and in Hawai'i, rates of ocean warming are projected to double by the end of the 21st century. However, current nearshore warming trends and their possible impacts on intertidal communities are not well understood. This study represents the first investigation into the possible effects of rising SST on intertidal algal and invertebrate communities across the Main Hawaiian Islands (MHI). By utilizing citizen-science data coupled with high-resolution, daily SST satellite measurements from 12 intertidal sites across the MHI from 2004-2019, the response of intertidal algal and invertebrate abundance and community diversity to changes in SST was investigated across multiple spatial scales. Results show high rates of SST warming (0.40°C Decade-1) over this study's timeframe, similar to predicted rates of warming for Hawai'i by the end of the 21st century. Changes in abundance and diversity in response to SST were variable among intertidal sites, but differences in antecedent SST among intertidal sites were significantly associated with community dissimilarity. In addition, a statistically significant positive relationship was found between SST and Simpson's diversity index, and a significant relationship was also found between SST and the abundance of six dominant taxa. For five of these six dominant taxa, antecedent SSTs over the 6-12 months preceding sampling were the most influential for describing changes to abundance. The increase in community diversity in response to higher SSTs was best explained by temperatures in the 10 months preceding sampling, and the resultant decreased abundance of dominant turf algae. These results highlight rapidly warming nearshore SSTs in Hawai'i and the longer-term effects of antecedent SSTs as significant drivers of change within Hawaiian intertidal communities. Therefore, we suggest that future research and management should consider the possibility of lagging effects of antecedent SST on intertidal communities in Hawai'i and elsewhere.
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Affiliation(s)
- Rebecca J Ward
- Department of Biology, University of Hawai'i at Hilo, Hilo, HI, United States of America
- Tropical Conservation Biology and Environmental Science Graduate Program, University of Hawai'i at Hilo, Hilo, HI, United States of America
| | - T Erin Cox
- Department of Biological Sciences, University of New Orleans, New Orleans, LA, United States of America
| | - Anuschka Faucci
- Math & Sciences Division, Leeward Community College, Pearl City, HI, United States of America
| | | | - Joanna Philippoff
- Curriculum Research & Development Group, University of Hawai'i at Mānoa, Honolulu, HI, United States of America
| | - Jessica L B Schaefer
- Animal Behavior Graduate Group, University of California Davis, 227 Life Sciences, Davis, CA, United States of America
| | - Ian M Ware
- Institute of Pacific Islands Forestry, Pacific Southwest Research Station, USDA Forest Service, Hilo, HI, United States of America
| | - Matthew L Knope
- Department of Biology, University of Hawai'i at Hilo, Hilo, HI, United States of America
- Tropical Conservation Biology and Environmental Science Graduate Program, University of Hawai'i at Hilo, Hilo, HI, United States of America
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6
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González-Barrios FJ, Estrada-Saldívar N, Pérez-Cervantes E, Secaira-Fajardo F, Álvarez-Filip L. Legacy effects of anthropogenic disturbances modulate dynamics in the world's coral reefs. GLOBAL CHANGE BIOLOGY 2023; 29:3285-3303. [PMID: 36932916 DOI: 10.1111/gcb.16686] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Revised: 03/03/2023] [Accepted: 03/07/2023] [Indexed: 05/16/2023]
Abstract
Rapidly changing conditions alter disturbance patterns, highlighting the need to better understand how the transition from pulse disturbances to more persistent stress will impact ecosystem dynamics. We conducted a global analysis of the impacts of 11 types of disturbances on reef integrity using the rate of change of coral cover as a measure of damage. Then, we evaluated how the magnitude of the damage due to thermal stress, cyclones, and diseases varied among tropical Atlantic and Indo-Pacific reefs and whether the cumulative impact of thermal stress and cyclones was able to modulate the responses of reefs to future events. We found that reef damage largely depends on the condition of a reef before a disturbance, disturbance intensity, and biogeographic region, regardless of the type of disturbance. Changes in coral cover after thermal stress events were largely influenced by the cumulative stress of past disturbances and did not depend on disturbance intensity or initial coral cover, which suggests that an ecological memory is present within coral communities. In contrast, the effect of cyclones (and likely other physical impacts) was primarily modulated by the initial reef condition and did not appear to be influenced by previous impacts. Our findings also underscore that coral reefs can recover if stressful conditions decrease, yet the lack of action to reduce anthropogenic impacts and greenhouse gas emissions continues to trigger reef degradation. We uphold that evidence-based strategies can guide managers to make better decisions to prepare for future disturbances.
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Affiliation(s)
- F Javier González-Barrios
- Biodiversity and Reef Conservation Laboratory, Unidad Académica de Sistemas Arrecifales, Instituto de Ciencias del Mar y Limnología, Universidad Nacional Autónoma de México, Puerto Morelos, Mexico
| | - Nuria Estrada-Saldívar
- Biodiversity and Reef Conservation Laboratory, Unidad Académica de Sistemas Arrecifales, Instituto de Ciencias del Mar y Limnología, Universidad Nacional Autónoma de México, Puerto Morelos, Mexico
| | - Esmeralda Pérez-Cervantes
- Biodiversity and Reef Conservation Laboratory, Unidad Académica de Sistemas Arrecifales, Instituto de Ciencias del Mar y Limnología, Universidad Nacional Autónoma de México, Puerto Morelos, Mexico
| | | | - Lorenzo Álvarez-Filip
- Biodiversity and Reef Conservation Laboratory, Unidad Académica de Sistemas Arrecifales, Instituto de Ciencias del Mar y Limnología, Universidad Nacional Autónoma de México, Puerto Morelos, Mexico
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7
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Tran LL, Johansen JL. Seasonal variability in resilience of a coral reef fish to marine heatwaves and hypoxia. GLOBAL CHANGE BIOLOGY 2023; 29:2522-2535. [PMID: 36843188 DOI: 10.1111/gcb.16624] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Revised: 01/15/2023] [Accepted: 01/17/2023] [Indexed: 05/31/2023]
Abstract
Climate change projections indicate more frequent and severe tropical marine heatwaves (MHWs) and accompanying hypoxia year-round. However, most studies have focused on peak summer conditions under the assumption that annual maximum temperatures will induce the greatest physiological consequences. This study challenges this idea by characterizing seasonal MHWs (i.e., mean, maximum, and cumulative intensities, durations, heating rates, and mean annual occurrence) and comparing metabolic traits (i.e., standard metabolic rate (SMR), Q10 of SMR, maximum metabolic rate (MMR), aerobic scope, and critical oxygen tension (Pcrit )) of winter- and summer-acclimatized convict tang (Acanthurus triostegus) to the combined effects of MHWs and hypoxia. Fish were exposed to one of six MHW treatments with seasonally varying maximum intensities (winter: 24.5, 26.5, 28.5°C; summer: 28.5, 30.5, 32.5°C), representing past and future MHWs under IPCC projections (i.e., +0, +2, +4°C). Surprisingly, MHW characteristics did not significantly differ between seasons, yet SMR was more sensitive to winter MHWs (mean Q10 = 2.92) than summer MHWs (mean Q10 = 1.81), despite higher absolute summer temperatures. Concurrently, MMR increased similarly among winter +2 and +4°C treatments (i.e., 26.5, 28.5°C) and all summer MHW treatments, suggesting a ceiling for maximal MMR increase. Aerobic scope did not significantly differ between seasons nor among MHW treatments. While mean Pcrit did not significantly vary between seasons, warming of +4°C during winter (i.e., 28.5°C) significantly increased Pcrit relative to the winter control group. Contrary to the idea of increased sensitivity to MHWs during the warmest time of year, our results reveal heightened sensitivity to the deleterious effects of winter MHWs, and that seasonal acclimatization to warmer summer conditions may bolster metabolic resilience to warming and hypoxia. Consequently, physiological sensitivity to MHWs and hypoxia may extend across larger parts of the year than previously expected, emphasizing the importance of evaluating climate change impacts during cooler seasons when essential fitness-related traits such as reproduction occur in many species.
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Affiliation(s)
- Leon L Tran
- Hawai'i Institute of Marine Biology, University of Hawai'i at Mānoa, Kāne'ohe, Hawaii, USA
| | - Jacob L Johansen
- Hawai'i Institute of Marine Biology, University of Hawai'i at Mānoa, Kāne'ohe, Hawaii, USA
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8
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Solar radiation, temperature and the reproductive biology of the coral Lobactis scutaria in a changing climate. Sci Rep 2023; 13:246. [PMID: 36604569 PMCID: PMC9816315 DOI: 10.1038/s41598-022-27207-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2022] [Accepted: 12/28/2022] [Indexed: 01/07/2023] Open
Abstract
Coral reefs worldwide are at risk due to climate change. Coral bleaching is becoming increasingly common and corals that survive bleaching events can suffer from temporary reproductive failure for several years. While water temperature is a key driver in causing coral bleaching, other environmental factors are involved, such as solar radiation. We investigated the individual and combined effects of temperature, photosynthetically active radiation (PAR), and ultraviolet radiation (UVR) on the spawning patterns and reproductive physiology of the Hawaiian mushroom coral Lobactis scutaria, using long-term experiments in aquaria. We examined effects on spawning timing, fertilisation success, and gamete physiology. Both warmer temperatures and filtering UVR altered the timing of spawning. Warmer temperatures caused a drop in fertilisation success. Warmer temperatures and higher PAR both negatively affected sperm and egg physiology. These results are concerning for the mushroom coral L. scutaria and similar reproductive data are urgently needed to predict future reproductive trends in other species. Nonetheless, thermal stress from global climate change will need to be adequately addressed to ensure the survival of reef-building corals in their natural environment throughout the next century and beyond. Until then, reproduction is likely to be increasingly impaired in a growing number of coral species.
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Maurya PK, Balakrishnan M, Raj R, Naik L, Fernandes L, Dabholkar N, Prabhudesai S, Ravindran J, Agarwadekar Y, Navelkar G. Augmented coral reef monitoring using a stationary reef monitoring system. ECOL INFORM 2023. [DOI: 10.1016/j.ecoinf.2023.101972] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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10
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Walker NS, Cornwell BH, Nestor V, Armstrong KC, Golbuu Y, Palumbi SR. Persistence of phenotypic responses to short-term heat stress in the tabletop coral Acropora hyacinthus. PLoS One 2022; 17:e0269206. [PMID: 36084033 PMCID: PMC9462741 DOI: 10.1371/journal.pone.0269206] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Accepted: 08/23/2022] [Indexed: 12/26/2022] Open
Abstract
Widespread mapping of coral thermal resilience is essential for developing effective management strategies and requires replicable and rapid multi-location assays of heat resistance and recovery. One- or two-day short-term heat stress experiments have been previously employed to assess heat resistance, followed by single assays of bleaching condition. We tested the reliability of short-term heat stress resistance, and linked resistance and recovery assays, by monitoring the phenotypic response of fragments from 101 Acropora hyacinthus colonies located in Palau (Micronesia) to short-term heat stress. Following short-term heat stress, bleaching and mortality were recorded after 16 hours, daily for seven days, and after one and two months of recovery. To follow corals over time, we utilized a qualitative, non-destructive visual bleaching score metric that correlated with standard symbiont retention assays. The bleaching state of coral fragments 16 hours post-heat stress was highly indicative of their state over the next 7 days, suggesting that symbiont population sizes within corals may quickly stabilize post-heat stress. Bleaching 16 hours post-heat stress predicted likelihood of mortality over the subsequent 3–5 days, after which there was little additional mortality. Together, bleaching and mortality suggested that rapid assays of the phenotypic response following short-term heat stress were good metrics of the total heat treatment effect. Additionally, our data confirm geographic patterns of intraspecific variation in Palau and show that bleaching severity among colonies was highly correlated with mortality over the first week post-stress. We found high survival (98%) and visible recovery (100%) two months after heat stress among coral fragments that survived the first week post-stress. These findings help simplify rapid, widespread surveys of heat sensitivity in Acropora hyacinthus by showing that standardized short-term experiments can be confidently assayed after 16 hours, and that bleaching sensitivity may be linked to subsequent survival using experimental assessments.
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Affiliation(s)
- Nia S. Walker
- Department of Biology, Hopkins Marine Station of Stanford University, Pacific Grove, California, United States of America
- * E-mail:
| | - Brendan H. Cornwell
- Department of Biology, Hopkins Marine Station of Stanford University, Pacific Grove, California, United States of America
| | | | - Katrina C. Armstrong
- Department of Biology, Hopkins Marine Station of Stanford University, Pacific Grove, California, United States of America
| | | | - Stephen R. Palumbi
- Department of Biology, Hopkins Marine Station of Stanford University, Pacific Grove, California, United States of America
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11
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Winston M, Oliver T, Couch C, Donovan MK, Asner GP, Conklin E, Fuller K, Grady BW, Huntington B, Kageyama K, Kindinger TL, Kozar K, Kramer L, Martinez T, McCutcheon A, McKenna S, Rodgers K, Shayler CK, Vargas-Angel B, Zgliczynski B. Coral taxonomy and local stressors drive bleaching prevalence across the Hawaiian Archipelago in 2019. PLoS One 2022; 17:e0269068. [PMID: 36048764 PMCID: PMC9436070 DOI: 10.1371/journal.pone.0269068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Accepted: 05/13/2022] [Indexed: 11/18/2022] Open
Abstract
The Hawaiian Archipelago experienced a moderate bleaching event in 2019—the third major bleaching event over a 6-year period to impact the islands. In response, the Hawai‘i Coral Bleaching Collaborative (HCBC) conducted 2,177 coral bleaching surveys across the Hawaiian Archipelago. The HCBC was established to coordinate bleaching monitoring efforts across the state between academic institutions, non-governmental organizations, and governmental agencies to facilitate data sharing and provide management recommendations. In 2019, the goals of this unique partnership were to: 1) assess the spatial and temporal patterns of thermal stress; 2) examine taxa-level patterns in bleaching susceptibility; 3) quantify spatial variation in bleaching extent; 4) compare 2019 patterns to those of prior bleaching events; 5) identify predictors of bleaching in 2019; and 6) explore site-specific management strategies to mitigate future bleaching events. Both acute thermal stress and bleaching in 2019 were less severe overall compared to the last major marine heatwave events in 2014 and 2015. Bleaching observed was highly site- and taxon-specific, driven by the susceptibility of remaining coral assemblages whose structure was likely shaped by previous bleaching and subsequent mortality. A suite of environmental and anthropogenic predictors was significantly correlated with observed bleaching in 2019. Acute environmental stressors, such as temperature and surface light, were equally important as previous conditions (e.g. historical thermal stress and historical bleaching) in accounting for variation in bleaching during the 2019 event. We found little evidence for acclimation by reefs to thermal stress in the main Hawaiian Islands. Moreover, our findings illustrate how detrimental effects of local anthropogenic stressors, such as tourism and urban run-off, may be exacerbated under high thermal stress. In light of the forecasted increase in severity and frequency of bleaching events, future mitigation of both local and global stressors is a high priority for the future of corals in Hawai‘i.
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Affiliation(s)
- Morgan Winston
- Cooperative Institute for Marine and Atmospheric Research, University of Hawai‘i, Honolulu, Hawai‘i, United States of America
- Pacific Islands Fisheries Science Center, National Marine Fisheries Service, Honolulu, Hawai‘i, United States of America
- Center for Global Discovery and Conservation Science and School of Geographic Sciences and Urban Planning, Arizona State University, Hilo, Hawai‘i, United States of America
- * E-mail:
| | - Thomas Oliver
- Pacific Islands Fisheries Science Center, National Marine Fisheries Service, Honolulu, Hawai‘i, United States of America
| | - Courtney Couch
- Cooperative Institute for Marine and Atmospheric Research, University of Hawai‘i, Honolulu, Hawai‘i, United States of America
- Pacific Islands Fisheries Science Center, National Marine Fisheries Service, Honolulu, Hawai‘i, United States of America
| | - Mary K. Donovan
- Center for Global Discovery and Conservation Science and School of Geographic Sciences and Urban Planning, Arizona State University, Hilo, Hawai‘i, United States of America
| | - Gregory P. Asner
- Center for Global Discovery and Conservation Science and School of Geographic Sciences and Urban Planning, Arizona State University, Hilo, Hawai‘i, United States of America
| | - Eric Conklin
- The Nature Conservancy, Honolulu, Hawai‘i, United States of America
| | - Kimberly Fuller
- Division of Aquatic Resources (O‘ahu), Anuenue Fisheries Research Center, Honolulu, Hawai‘i, United States of America
| | - Bryant W. Grady
- Center for Global Discovery and Conservation Science and School of Geographic Sciences and Urban Planning, Arizona State University, Hilo, Hawai‘i, United States of America
| | - Brittany Huntington
- Cooperative Institute for Marine and Atmospheric Research, University of Hawai‘i, Honolulu, Hawai‘i, United States of America
- Pacific Islands Fisheries Science Center, National Marine Fisheries Service, Honolulu, Hawai‘i, United States of America
| | - Kazuki Kageyama
- Division of Aquatic Resources (O‘ahu), Anuenue Fisheries Research Center, Honolulu, Hawai‘i, United States of America
| | - Tye L. Kindinger
- Pacific Islands Fisheries Science Center, National Marine Fisheries Service, Honolulu, Hawai‘i, United States of America
| | - Kelly Kozar
- Pacific Island Network Inventory and Monitoring Program, Hawai‘i National Park, Hawai‘i, United States of America
| | - Lindsey Kramer
- Division of Aquatic Resources (Kona), Kailua-Kona, Hawai‘i, United States of America
| | - Tatiana Martinez
- Division of Aquatic Resources (Maui), Wailuku, Hawai‘i, United States of America
| | - Amanda McCutcheon
- Pacific Island Network Inventory and Monitoring Program, Hawai‘i National Park, Hawai‘i, United States of America
| | - Sheila McKenna
- Pacific Island Network Inventory and Monitoring Program, Hawai‘i National Park, Hawai‘i, United States of America
| | - Ku‘ulei Rodgers
- Hawai‘i Institute of Marine Biology, Kāne‘ohe, Hawai‘i, United States of America
| | | | - Bernardo Vargas-Angel
- Cooperative Institute for Marine and Atmospheric Research, University of Hawai‘i, Honolulu, Hawai‘i, United States of America
- Pacific Islands Fisheries Science Center, National Marine Fisheries Service, Honolulu, Hawai‘i, United States of America
| | - Brian Zgliczynski
- Scripps Institution of Oceanography, La Jolla, California, United States of America
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12
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Sully S, Hodgson G, van Woesik R. Present and future bright and dark spots for coral reefs through climate change. GLOBAL CHANGE BIOLOGY 2022; 28:4509-4522. [PMID: 35106864 PMCID: PMC9303460 DOI: 10.1111/gcb.16083] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Revised: 12/12/2021] [Accepted: 01/04/2022] [Indexed: 05/08/2023]
Abstract
Marine heatwaves can cause coral bleaching and reduce coral cover on reefs, yet few studies have identified "bright spots," where corals have recently shown a capacity to survive such pressures. We analyzed 7714 worldwide surveys from 1997 to 2018 along with 14 environmental and temperature metrics in a hierarchical Bayesian model to identify conditions that contribute to present-day coral cover. We also identified locations with significantly higher (i.e., "bright spots") and lower coral cover (i.e., "dark spots") than regionally expected. In addition, using 4-km downscaled data of Representative Concentration Pathways (RCPs) 4.5 and 8.5, we projected coral cover on reefs for the years 2050 and 2100. Coral cover on modern reefs was positively associated with historically high maximum sea-surface temperatures (SSTs), and negatively associated with high contemporary SSTs, tropical-cyclone frequencies, and human-population densities. By 2100, under RCP8.5, we projected relative decreases in coral cover of >40% on most reefs globally but projected less decline on reefs in Indonesia, Malaysia, the central Philippines, New Caledonia, Fiji, and French Polynesia, which should be focal localities for multinational networks of protected areas.
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Affiliation(s)
- Shannon Sully
- Institute for Global EcologyFlorida Institute of TechnologyMelbourneFloridaUSA
| | - Gregor Hodgson
- Coral Reef Consultants LLCCalabasasCaliforniaUSA
- Emeritus, Reef Check FoundationMarina del ReyCaliforniaUSA
| | - Robert van Woesik
- Institute for Global EcologyFlorida Institute of TechnologyMelbourneFloridaUSA
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13
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Bowden CL, Streit RP, Bellwood DR, Tebbett SB. A 3D perspective on sediment turnover and feeding selectivity in blennies. MARINE POLLUTION BULLETIN 2022; 180:113799. [PMID: 35665616 DOI: 10.1016/j.marpolbul.2022.113799] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Revised: 05/23/2022] [Accepted: 05/24/2022] [Indexed: 06/15/2023]
Abstract
Sediments in algal turfs can modify a wide variety of key ecological processes on coral reefs. While some larger reef fishes can remove these turf-bound sediments, the role of small, yet abundant, cryptobenthic fishes is currently unclear. To address this knowledge gap, we explored the extent to which the blenny, Ecsenius stictus, can shape sediment dynamics on coral reefs by quantifying their sediment ingestion and space use. Per unit body mass, E. stictus process sediments at comparable rates to key parrotfish and surgeonfish species. However, in absolute terms, E. stictus has a negligible influence on net sediment dynamics, despite their abundance. Behavioural observations and 3D photogrammetry reveal that E. stictus preferentially feed and rest on elevated surfaces; potentially because of low sediment loads on these surfaces. Overall, E. stictus may be responding to sediment loads rather than manipulating them; it is a passenger rather than a driver in reef processes.
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Affiliation(s)
- Casey L Bowden
- Research Hub for Coral Reef Ecosystem Functions, College of Science and Engineering and ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, Queensland 4811, Australia.
| | - Robert P Streit
- Research Hub for Coral Reef Ecosystem Functions, College of Science and Engineering and ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, Queensland 4811, Australia
| | - David R Bellwood
- Research Hub for Coral Reef Ecosystem Functions, College of Science and Engineering and ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, Queensland 4811, Australia
| | - Sterling B Tebbett
- Research Hub for Coral Reef Ecosystem Functions, College of Science and Engineering and ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, Queensland 4811, Australia
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14
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Thoral F, Montie S, Thomsen MS, Tait LW, Pinkerton MH, Schiel DR. Unravelling seasonal trends in coastal marine heatwave metrics across global biogeographical realms. Sci Rep 2022; 12:7740. [PMID: 35545696 PMCID: PMC9095592 DOI: 10.1038/s41598-022-11908-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Accepted: 04/27/2022] [Indexed: 11/22/2022] Open
Abstract
Marine heatwaves (MHWs) can cause dramatic changes to ecologically, culturally, and economically important coastal ecosystems. To date, MHW studies have focused on geographically isolated regions or broad-scale global oceanic analyses, without considering coastal biogeographical regions and seasons. However, to understand impacts from MHWs on diverse coastal communities, a combined biogeographical-seasonal approach is necessary, because (1) bioregions reflect community-wide temperature tolerances and (2) summer or winter heatwaves likely affect communities differently. We therefore carried out season-specific Theil–Sen robust linear regressions and Pettitt change point analyses from 1982 to 2021 on the number of events, number of MHW days, mean intensity, maximum intensity, and cumulative intensity of MHWs, for each of the world’s 12 major coastal biogeographical realms. We found that 70% of 240 trend analyses increased significantly, 5% decreased and 25% were unaffected. There were clear differences between trends in metrics within biogeographical regions, and among seasons. For the significant increases, most change points occurred between 1998 and 2006. Regression slopes were generally positive across MHW metrics, seasons, and biogeographical realms as well as being highest after change point detection. Trends were highest for the Arctic, Northern Pacific, and Northern Atlantic realms in summer, and lowest for the Southern Ocean and several equatorial realms in other seasons. Our analysis highlights that future case studies should incorporate break point changes and seasonality in MHW analysis, to increase our understanding of how future, more frequent, and stronger MHWs will affect coastal ecosystems.
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Affiliation(s)
- François Thoral
- Marine Ecology Research Group and Centre for Integrative Ecology, School of Biological Sciences, University of Canterbury, Christchurch, New Zealand. .,NIWA, Wellington, New Zealand.
| | - Shinae Montie
- Marine Ecology Research Group and Centre for Integrative Ecology, School of Biological Sciences, University of Canterbury, Christchurch, New Zealand
| | - Mads S Thomsen
- Marine Ecology Research Group and Centre for Integrative Ecology, School of Biological Sciences, University of Canterbury, Christchurch, New Zealand
| | - Leigh W Tait
- Marine Ecology Research Group and Centre for Integrative Ecology, School of Biological Sciences, University of Canterbury, Christchurch, New Zealand.,NIWA, Christchurch, New Zealand
| | | | - David R Schiel
- Marine Ecology Research Group and Centre for Integrative Ecology, School of Biological Sciences, University of Canterbury, Christchurch, New Zealand
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15
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Chen GK, Dai CF. Using 3D photogrammetry to quantify the subtle differences of coral reefs under the impacts of marine activities. MARINE POLLUTION BULLETIN 2021; 173:113032. [PMID: 34689075 DOI: 10.1016/j.marpolbul.2021.113032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 10/02/2021] [Accepted: 10/02/2021] [Indexed: 06/13/2023]
Abstract
Marine activities may cause the degradation of coral reefs. The composition of benthic communities and seawater quality have been commonly used as the proxies to assess the impacts of marine activities. However, these proxies may not be able to detect the subtle differences within homogeneous environment. We used photogrammetry to quantify the subtle differences of structural complexity between heavily and lightly trafficked sites at Wanlitong, southern Taiwan. Our study demonstrated that the impacts of marine activities can be detected within tens of meters through quantifying structural complexity of coral reefs. Vector ruggedness measure (VRM) is a more suitable metric than conventional linear rugosity to detect such impacts. The correlations between structural complexity and coral cover have variances while comparing with previous studies. The results show that using photogrammetry to quantify the structure of coral reefs can provide a novel aspect to evaluate the subtle differences caused by marine activities.
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Affiliation(s)
| | - Chang Feng Dai
- Institute of Oceanography, National Taiwan University, Taipei 10617, Taiwan
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16
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Nolan MKB, Schmidt-Roach S, Davis AR, Aranda M, Howells EJ. Widespread bleaching in the One Tree Island lagoon (Southern Great Barrier Reef) during record-breaking temperatures in 2020. ENVIRONMENTAL MONITORING AND ASSESSMENT 2021; 193:590. [PMID: 34417871 PMCID: PMC8379602 DOI: 10.1007/s10661-021-09330-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Accepted: 07/22/2021] [Indexed: 06/13/2023]
Abstract
The global marine environment has been impacted significantly by climate change. Ocean temperatures are rising, and the frequency, duration and intensity of marine heatwaves are increasing, particularly affecting coral reefs. Coral bleaching events are becoming more common, with less recovery time between events. Anomalous temperatures at the start of 2020 caused widespread bleaching across the Great Barrier Reef (GBR), extending to southern, previously less affected reefs such as One Tree Island. Here, nine video transects were conducted at One Tree Island, in the Capricorn Bunker Group, and analysed for community composition and diversity, and the extent of bleaching across taxa. Average live hard coral cover across the area was 11.62%, and almost half of this was identified as severely bleached. This bleaching event is concerning as it occurred in an area previously considered a potential refuge for corals and associated fauna from the risks of climate warming. Due to the global impacts of COVID-19 during 2020, this report provides one of potentially few monitoring efforts of coral bleaching.
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Affiliation(s)
- Megan K B Nolan
- Red Sea Research Centre, King Abdullah University of Science and Technology, Thuwal, 23955-6900, Saudi Arabia.
| | - Sebastian Schmidt-Roach
- Red Sea Research Centre, King Abdullah University of Science and Technology, Thuwal, 23955-6900, Saudi Arabia
| | - Andrew R Davis
- Centre for Sustainable Ecosystem Solutions and School of Earth, Atmospheric and Life Sciences, University of Wollongong, Wollongong, NSW, 2522, Australia
| | - Manuel Aranda
- Red Sea Research Centre, King Abdullah University of Science and Technology, Thuwal, 23955-6900, Saudi Arabia
| | - Emily J Howells
- Centre for Sustainable Ecosystem Solutions and School of Earth, Atmospheric and Life Sciences, University of Wollongong, Wollongong, NSW, 2522, Australia
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17
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3D assessment of a coral reef at Lalo Atoll reveals varying responses of habitat metrics following a catastrophic hurricane. Sci Rep 2021; 11:12050. [PMID: 34103641 PMCID: PMC8187721 DOI: 10.1038/s41598-021-91509-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Accepted: 05/26/2021] [Indexed: 11/24/2022] Open
Abstract
Extreme disturbances such as hurricanes can cause reductions in coral cover and three-dimensional (3D) structural complexity of coral reefs. We examined changes in structural complexity utilizing 3D reconstruction of a coral-reef site before and after Hurricane Walaka passed through Lalo of the Northwestern Hawaiian Islands. This event resulted in complete destruction of the coral-reef habitat, with dramatic changes in benthic cover from pre-hurricane tabulate coral to post-hurricane rubble. Rugosity and mean slope decreased after the hurricane, while structural complexity, captured by vector ruggedness measure (VRM), showed resolution-specific responses. This metric captured the structural complexity of rubble at a high raster resolution of 1 cm and that of tabulate coral at lower resolutions, resulting in decreases in mean VRM values at 2- and 4-cm resolutions but an increase at 1-cm resolution. Variability in profile and planform curvature was reduced after the hurricane due to a disappearance of extreme curvature values created by the tabulate coral after the hurricane. This study highlights the varying responses of habitat complexity metrics to the complete destruction of a coral reef and provides us with insights into how choices of habitat complexity metrics can affect quantitative assessments of 3D habitat structure.
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18
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Majerova E, Carey FC, Drury C, Gates RD. Preconditioning improves bleaching tolerance in the reef-building coral Pocillopora acuta through modulations in the programmed cell death pathways. Mol Ecol 2021; 30:3560-3574. [PMID: 34008873 DOI: 10.1111/mec.15988] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Revised: 05/07/2021] [Accepted: 05/10/2021] [Indexed: 12/25/2022]
Abstract
Reef-building corals rely on intracellular algal symbionts to meet energetic demands. Increasing extreme weather driven by climate change often leads to disruption of this symbiosis and to coral death. Corals can better withstand stress after previous exposure to sublethal conditions, but the mechanisms for this resilience remain unclear. Here, we show that a three-day thermal preconditioning increases tolerance of acute heat stress through modulations in cell death pathways in the stony coral Pocillopora acuta. In preconditioned corals, the ratio of pro-survival (pa-Bcl-2 and pa-BI-1) to pro-death (pa-BAK and pa-BAX) gene expression increased and the corals underwent significantly less bleaching. When treated with Bcl-2 inhibitor, corals lost the improved thermal tolerance, suggesting an important role of programmed cell death in coral bleaching and acclimatization. During heat stress, the activity of acid phosphatase increased but caspase-3 did not, suggesting the involvement of autophagy/symbiophagy rather than apoptosis in this process. A similar shift in gene expression also occurs in thermally stressed corals that have been exposed to naturally higher temperatures during summer thermal maxima in Kāne'ohe Bay, Hawai'i, suggesting that corals can increase their resilience to realistic warming events during high-risk periods through alterations in cell signalling. These data suggest that programmed cell death pathways underly coral acclimatization and resilience and may be important for coral reef conservation and management.
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Affiliation(s)
- Eva Majerova
- Hawai'i Institute of Marine Biology, University of Hawai'i at Mānoa, Kāne'ohe, HI, USA
| | - Fiona C Carey
- Hawai'i Institute of Marine Biology, University of Hawai'i at Mānoa, Kāne'ohe, HI, USA
| | - Crawford Drury
- Hawai'i Institute of Marine Biology, University of Hawai'i at Mānoa, Kāne'ohe, HI, USA
| | - Ruth D Gates
- Hawai'i Institute of Marine Biology, University of Hawai'i at Mānoa, Kāne'ohe, HI, USA
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19
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Blanckaert ACA, de Barros Marangoni LF, Rottier C, Grover R, Ferrier-Pagès C. Low levels of ultra-violet radiation mitigate the deleterious effects of nitrate and thermal stress on coral photosynthesis. MARINE POLLUTION BULLETIN 2021; 167:112257. [PMID: 33756374 DOI: 10.1016/j.marpolbul.2021.112257] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Revised: 03/05/2021] [Accepted: 03/07/2021] [Indexed: 05/20/2023]
Abstract
Reef ecosystems are under increasing pressure from global and local stressors. Rising seawater temperature and high ultraviolet radiation (UVR) levels are the main drivers of the disruption of the coral-dinoflagellate symbiosis (bleaching). Bleaching can also be exacerbated by nitrate contamination in coastal reefs. However, the underlying physiological mechanisms are still poorly understood. Here, we assessed the physiological and oxidative state of the scleractinian coral Pocillopora damicornis, maintained eight weeks in a crossed-factorial design including two temperatures (26 °C or 30 °C), and two nitrate (0.5 and 3 μM-enriched), and UVR (no UVR and 25/1.5 Wm-2 UVA/B) levels. Nitrate enrichment, and high temperature, significantly impaired coral photosynthesis. However, UVR alleviated the nitrate and temperature-induced decrease in photosynthesis, by increasing the coral's antioxidant capacity. The present study contributes to our understanding of the combined effects of abiotic stressors on coral bleaching susceptibility. Such information is urgently needed to refine reef management strategies.
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Affiliation(s)
- Alice C A Blanckaert
- Sorbonne Université, UPMC Université Paris VI, IFD-ED 129, Paris Cedex 05, France; Centre Scientifique de Monaco, Coral Ecophysiology team, 8 Quai Antoine 1er, MC 98000, Monaco.
| | | | - Cécile Rottier
- Centre Scientifique de Monaco, Coral Ecophysiology team, 8 Quai Antoine 1er, MC 98000, Monaco
| | - Renaud Grover
- Centre Scientifique de Monaco, Coral Ecophysiology team, 8 Quai Antoine 1er, MC 98000, Monaco
| | - Christine Ferrier-Pagès
- Centre Scientifique de Monaco, Coral Ecophysiology team, 8 Quai Antoine 1er, MC 98000, Monaco
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20
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Wall CB, Ricci CA, Wen AD, Ledbetter BE, Klinger DE, Mydlarz LD, Gates RD, Putnam HM. Shifting baselines: Physiological legacies contribute to the response of reef corals to frequent heatwaves. Funct Ecol 2021. [DOI: 10.1111/1365-2435.13795] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Christopher B. Wall
- Hawai'i Institute of Marine Biology University of Hawai'i at Mānoa Kāne'ohe HI USA
- Pacific Biosciences Research Center University of Hawai'i at Mānoa Honolulu HI USA
| | - Contessa A. Ricci
- Department of Biology University of Texas at Arlington Arlington TX USA
| | - Alexandra D. Wen
- Hawai'i Institute of Marine Biology University of Hawai'i at Mānoa Kāne'ohe HI USA
- Rosenstiel School of Marine and Atmospheric Science University of Miami Miami FL USA
| | - Bren E. Ledbetter
- Department of Biology University of Texas at Arlington Arlington TX USA
| | | | - Laura D. Mydlarz
- Department of Biology University of Texas at Arlington Arlington TX USA
| | - Ruth D. Gates
- Hawai'i Institute of Marine Biology University of Hawai'i at Mānoa Kāne'ohe HI USA
| | - Hollie M. Putnam
- Department of Biological Sciences University of Rhode Island Kingston RI USA
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21
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Abstract
There is a growing interest in the endolithic microbial biofilms inhabiting skeletons of living corals because of their contribution to coral reef bioerosion and the reputed benefits they provide to live coral hosts. Here, we sought to identify possible correlations between coral interspecific patterns in skeletal morphology and variability in the biomass of, and chlorophyll concentrations within, the endolithic biofilm. We measured five morphological characteristics of five coral species and the biomasses/chlorophyll concentrations of their endolithic microbiome, and we compare interspecific patterns in these variables. We propose that the specific density of a coral’s skeleton and its capacity for capturing and scattering incident light are the main correlates of endolithic microbial biomass. Our data suggest that the correlation between light capture and endolithic biomass is likely influenced by how the green microalgae (obligatory microborers) respond to skeletal variability. These results demonstrate that coral species differ significantly in their endolithic microbial biomass and that their skeletal structure could be used to predict these interspecific differences. Further exploring how and why the endolithic microbiome varies between coral species is vital in defining the role of these microbes on coral reefs, both now and in the future. IMPORTANCE Microbial communities living inside the skeletons of living corals play a variety of important roles within the coral meta-organism, both symbiotic and parasitic. Properly contextualizing the contribution of these enigmatic microbes to the life history of coral reefs requires knowledge of how these endolithic biofilms vary between coral species. To this effect, we measured differences in the morphology of five coral species and correlate these with variability in the biomass of the skeletal biofilms. We found that the density of the skeleton and its capacity to trap incoming light, as opposed to scattering it back into the surrounding water, both significantly correlated with skeletal microbial biomass. These patterns are likely driven by how dominant green microalgae in the endolithic niche, such as Ostreobium spp., are responding to the skeletal morphology. This study highlights that the structure of a coral’s skeleton could be used to predict the biomass of its resident endolithic biofilm.
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22
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Good AM, Bahr KD. The coral conservation crisis: interacting local and global stressors reduce reef resiliency and create challenges for conservation solutions. SN APPLIED SCIENCES 2021. [DOI: 10.1007/s42452-021-04319-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
AbstractCoral reefs are one of the most productive and biodiverse ecosystems in the world. Humans rely on these coral reef ecosystems to provide significant ecological and economic resources; however, coral reefs are threatened by numerous local and global anthropogenic factors that cause significant environmental change. The interactions of these local and global human impacts may increase the rate of coral reef degradation. For example, there are many local influences (i.e., sedimentation and submarine groundwater discharge) that may exacerbate coral bleaching and mortality. Therefore, researchers and resource managers cannot limit their narratives and actions to mitigating a sole stressor. With the continued increase in greenhouse gas emissions, management strategies and restoration techniques need to account for the scale at which environmental change occurs. This review aims to outline the various local and global anthropogenic stressors threatening reef resiliency and address the recent disagreements surrounding present-day conservation practices. Unfortunately, there is no one solution to preserve and restore all coral reefs. Each coral reef region is challenged by numerous interactive stressors that affect its ecosystem response, recovery, and services in various ways. This review discusses, while global reef degradation occurs, local solutions should be implemented to efficiently protect the coral reef ecosystem services that are valuable to marine and terrestrial environments.
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23
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Impact to Coral Reef Populations at Hā‘ena and Pila‘a, Kaua‘i, Following a Record 2018 Freshwater Flood Event. DIVERSITY-BASEL 2021. [DOI: 10.3390/d13020066] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Many corals and reef-dwelling organisms are susceptible to the impacts of storm events, which are typically characterized by large inputs of freshwater, sediment, and nutrients. The majority of storm effects are focused on shallow, nearshore reef flats, as low salinity and sedimentation tend to dissipate with depth and distance from shore. In April 2018, record rainfall on the northern coast of Kaua‘i caused extensive flooding and landslides, introducing large amounts of freshwater and sediment into nearshore reefs. Using benthic and fish transects from 2016–2019 and temperature, sediment, and rainfall data gathered pre- and post-flood, this study aimed to quantify and explicate the effects of flooding on the various biotic populations of two reef habitats at Pila‘a and Hā‘ena, Kaua‘i. Results from the shallow Pila‘a reef suggest sediment and freshwater-associated declines in mean urchin abundance (−52.0%) and increases in mean coral bleaching (+54.5%) at the flood-prone eastern sector. Additionally, decreases in mean urchin (−65.7%) and fish (−42.3%) populations were observed at shallow Hā‘ena transects, but not deep sites, supporting the occurrence of depth-specific affliction. Multivariate community-level analyses affirmed much of these results, showing a significant shift in community structure before and after the flood at both Pila‘a and Hā‘ena. The outcomes of this study are pertinent to strategic design and solution development by local aquatic resource managers, especially as anthropogenic climate change continues to increase the frequency, duration, and intensity of storm events.
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24
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Gaspar TL, Quimbayo JP, Ozekoski R, Nunes LT, Aued AW, Mendes TC, Garrido AG, Segal B. Severe coral bleaching of Siderastrea stellata at the only atoll in the South Atlantic driven by sequential Marine Heatwaves. BIOTA NEOTROPICA 2021. [DOI: 10.1590/1676-0611-bn-2020-1131] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/22/2023]
Abstract
Abstract: Threatened by global warming and extreme climatic events, such as El Niño Southern Oscillation (ENSO) and Marine Heatwaves (MHW), coral reefs worldwide faced the worst bleaching and mortality event between 2014 and 2017, induced by the 2015/2016 ENSO. We evaluated the impacts of ENSO and MHW episodes on bleaching and mortality frequencies of Siderastrea stellata at Rocas Atoll, Southwestern Atlantic, using visual censuses conducted in 2016, 2017 and 2019. Bleaching rate varied significantly along the sampling period (11.71% in 2016, 1.52% in 2017, and 88% in 2019), but mortality was always less than 4%. Bleaching events in Atlantic reefs have been constantly associated with ENSO, until these recent events of the last two years. We suggest that MHW were probably the primary driver of the observed bleaching, especially in 2019, when much higher bleaching rates were observed than in ENSO periods. Although Southwestern Atlantic massive corals are considered more resistant to thermal stress than reefs corals worldwide, the strong events registered since 2019 highlight the need for continuous monitoring to better understand coral bleaching dynamics and improve predictions on the effects of global change in the region.
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Affiliation(s)
| | | | | | | | | | | | | | - Bárbara Segal
- Universidade Federal de Santa Catarina, Brasil; Instituto Coral Vivo, Brasil
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25
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Quimpo TJR, Requilme JNC, Gomez EJ, Sayco SLG, Tolentino MPS, Cabaitan PC. Low coral bleaching prevalence at the Bolinao-Anda Reef Complex, northwestern Philippines during the 2016 thermal stress event. MARINE POLLUTION BULLETIN 2020; 160:111567. [PMID: 32891963 DOI: 10.1016/j.marpolbul.2020.111567] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Revised: 08/03/2020] [Accepted: 08/10/2020] [Indexed: 06/11/2023]
Abstract
Here, we examined the coral bleaching responses during the 2016 thermal stress event and post-bleaching changes in coral communities in the heavily disturbed reefs of the Bolinao-Anda Reef Complex (BARC), northwestern Philippines. Less than 25% of colonies bleached, with 77% attributed to five genera (Dipsastrea, Porites, Fungia, Seriatopora, and Montipora). Coral bleaching prevalence was associated with site location, coral composition, and coral abundance, suggesting that small-scale variation (<20 km) in coral communities (taxa and density) influences spatial variation in coral bleaching prevalence. There was no noticeable change in coral composition and cover two years after the bleaching event as exposure to chronic disturbance likely selected for the dominance of stress tolerant coral taxa and communities. Results show that the 2016 thermal stress event caused coral bleaching but with low prevalence at the BARC, which suggests that disturbed reefs may provide spatial refuge to coral communities from thermal stress.
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Affiliation(s)
- Timothy Joseph R Quimpo
- The Marine Science Institute, College of Science, University of the Philippines, Diliman, Quezon City 1101, Philippines
| | - Jeremiah Noelle C Requilme
- The Marine Science Institute, College of Science, University of the Philippines, Diliman, Quezon City 1101, Philippines
| | - Elizabeth J Gomez
- The Marine Science Institute, College of Science, University of the Philippines, Diliman, Quezon City 1101, Philippines
| | - Sherry Lyn G Sayco
- The Marine Science Institute, College of Science, University of the Philippines, Diliman, Quezon City 1101, Philippines
| | - Mark Paulo S Tolentino
- The Marine Science Institute, College of Science, University of the Philippines, Diliman, Quezon City 1101, Philippines
| | - Patrick C Cabaitan
- The Marine Science Institute, College of Science, University of the Philippines, Diliman, Quezon City 1101, Philippines.
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26
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The Hawaiian Koʻa Card: coral health and bleaching assessment color reference card for Hawaiian corals. SN APPLIED SCIENCES 2020. [DOI: 10.1007/s42452-020-03487-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
Abstract
AbstractCoral reefs are the foundation to our social, cultural, and economic life; however, reefs around the world are currently being threatened by many local and global impacts. Ongoing increases in seawater temperature pose significant threats to the integrity of these valuable ecosystems through extensive coral bleaching events. Therefore, we developed a coral health reference card, the Hawaiian Koʻa (coral) Card, to assess and quantify coral bleaching and to educate the community about its impacts in Hawai‘i. To accurately quantify the change in coral color during bleaching, controlled laboratory studies followed by field validations and surveys were conducted. Colors presented on the Hawaiian Koʻa Card have been linked to physiological state and health (e.g., symbiont density, chlorophyll levels, photosynthetic performance) of common coral species in Hawaiʻi due to bleaching. The Hawaiian Koʻa Card provides a technical solution to inform and improve management of our nearshore resources through collaborative monitoring efforts by community members, educators, researchers, and managers on a state-wide scale, which will assist in determining management efficacy, identifying regions and species of resilience, establishing baselines and focus areas, and developing and executing rapid response plans.
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Johnston EC, Counsell CWW, Sale TL, Burgess SC, Toonen RJ. The legacy of stress: Coral bleaching impacts reproduction years later. Funct Ecol 2020. [DOI: 10.1111/1365-2435.13653] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Affiliation(s)
- Erika C. Johnston
- School of Ocean and Earth Science Technology Hawai‘i Institute of Marine BiologyUniversity of Hawai‘i at Mānoa Kāne‘ohe HI USA
- Department of Biological Science Florida State University Tallahassee FL USA
| | - Chelsie W. W. Counsell
- School of Ocean and Earth Science Technology Hawai‘i Institute of Marine BiologyUniversity of Hawai‘i at Mānoa Kāne‘ohe HI USA
| | - Tayler L. Sale
- Department of Biology University of Hawai‘i at Mānoa Honolulu HI USA
| | - Scott C. Burgess
- Department of Biological Science Florida State University Tallahassee FL USA
| | - Robert J. Toonen
- School of Ocean and Earth Science Technology Hawai‘i Institute of Marine BiologyUniversity of Hawai‘i at Mānoa Kāne‘ohe HI USA
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Metrics of Coral Reef Structural Complexity Extracted from 3D Mesh Models and Digital Elevation Models. REMOTE SENSING 2020. [DOI: 10.3390/rs12172676] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Underwater photogrammetry has been increasingly used in coral-reef research in recent years. Habitat metrics extracted from resulting three-dimensional (3D) reconstructions can be used to examine associations between the structural complexity of the reef habitats and the distribution of reef organisms. We created simulated 3D models of bare surface structures and 3D reconstructions of coral morphologies to investigate the behavior of various habitat metrics that were extracted from both Digital Elevation Models (DEMs) and 3D mesh models. Analyzing the resulting values provided us with important insights into how these metrics would compare with one another in the characterization of coral-reef habitats. Surface complexity (i.e., reef rugosity), fractal dimension extracted from DEMs and vector dispersion obtained from 3D mesh models exhibited consistent patterns in the ranking of structural complexity among the simulated bare surfaces and coral morphologies. The vector ruggedness measure obtained from DEMs at three different resolutions of 1, 2, and 4 cm effectively captured differences in the structural complexity among different coral morphologies. Profile curvature and planform curvature, on the other hand, were better suited to capture the structural complexity derived from surface topography such as walls and overhanging ledges. Our results indicate that habitat metrics extracted from DEMs are generally suitable when characterizing a relatively large plot of a coral reef captured from an overhead planar angle, while the 3D metric of vector dispersion is suitable when characterizing a coral colony or a relatively small plot methodically captured from various angles.
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Storlazzi CD, Cheriton OM, van Hooidonk R, Zhao Z, Brainard R. Internal tides can provide thermal refugia that will buffer some coral reefs from future global warming. Sci Rep 2020; 10:13435. [PMID: 32778666 PMCID: PMC7417736 DOI: 10.1038/s41598-020-70372-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Accepted: 07/23/2020] [Indexed: 12/02/2022] Open
Abstract
Observations show ocean temperatures are rising due to climate change, resulting in a fivefold increase in the incidence of regional-scale coral bleaching events since the 1980s; analyses based on global climate models forecast bleaching will become an annual event for most of the world’s coral reefs within 30–50 yr. Internal waves at tidal frequencies can regularly flush reefs with cooler waters, buffering the thermal stress from rising sea-surface temperatures. Here we present the first global maps of the effects these processes have on bleaching projections for three IPCC-AR5 emissions scenarios. Incorporating semidiurnal temperature fluctuations into the projected water temperatures at depth creates a delay in the timing of annual severe bleaching ≥ 10 yr (≥ 20 yr) for 38% (9%), 15% (1%), and 1% (0%) of coral reef sites for the low, moderate, and high emission scenarios, respectively; regional averages can reach twice as high. These cooling effects are greatest later in twenty-first century for the moderate emission scenarios, and around the middle twenty-first century for the highest emission scenario. Our results demonstrate how these effects could delay bleaching for corals, providing thermal refugia. Identification of such areas could be a factor for the selection of coral reef marine protected areas.
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Affiliation(s)
- Curt D Storlazzi
- U.S. Geological Survey, Pacific Coastal and Marine Science Center, 2885 Mission Street, Santa Cruz, CA, 95060, USA.
| | - Olivia M Cheriton
- U.S. Geological Survey, Pacific Coastal and Marine Science Center, 2885 Mission Street, Santa Cruz, CA, 95060, USA
| | - Ruben van Hooidonk
- Cooperative Institute for Marine and Atmospheric Studies, University of Miami, Miami, FL, 33149, USA
| | - Zhongxiang Zhao
- Applied Physics Laboratory, University of Washington, Seattle, WA, 98105, USA
| | - Russell Brainard
- King Abdullah University of Science and Technology, Red Sea Research Center, Thuwal, Saudi Arabia
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Multi-Temporal UAV Data and Object-Based Image Analysis (OBIA) for Estimation of Substrate Changes in a Post-Bleaching Scenario on a Maldivian Reef. REMOTE SENSING 2020. [DOI: 10.3390/rs12132093] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Coral reefs are declining worldwide as a result of the effects of multiple natural and anthropogenic stressors, including regional-scale temperature-induced coral bleaching. Such events have caused significant coral mortality, leading to an evident structural collapse of reefs and shifts in associated benthic communities. In this scenario, reasonable mapping techniques and best practices are critical to improving data collection to describe spatial and temporal patterns of coral reefs after a significant bleaching impact. Our study employed the potential of a consumer-grade drone, coupled with structure from motion and object-based image analysis to investigate for the first time a tool to monitor changes in substrate composition and the associated deterioration in reef environments in a Maldivian shallow-water coral reef. Three key substrate types (hard coral, coral rubble and sand) were detected with high accuracy on high-resolution orthomosaics collected from four sub-areas. Multi-temporal acquisition of UAV data allowed us to compare the classified maps over time (February 2017, November 2018) and obtain evidence of the relevant deterioration in structural complexity of flat reef environments that occurred after the 2016 mass bleaching event. We believe that our proposed methodology offers a cost-effective procedure that is well suited to generate maps for the long-term monitoring of changes in substrate type and reef complexity in shallow water.
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Matsuda SB, Huffmyer AS, Lenz EA, Davidson JM, Hancock JR, Przybylowski A, Innis T, Gates RD, Barott KL. Coral Bleaching Susceptibility Is Predictive of Subsequent Mortality Within but Not Between Coral Species. Front Ecol Evol 2020. [DOI: 10.3389/fevo.2020.00178] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
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França FM, Benkwitt CE, Peralta G, Robinson JPW, Graham NAJ, Tylianakis JM, Berenguer E, Lees AC, Ferreira J, Louzada J, Barlow J. Climatic and local stressor interactions threaten tropical forests and coral reefs. Philos Trans R Soc Lond B Biol Sci 2020; 375:20190116. [PMID: 31983328 PMCID: PMC7017775 DOI: 10.1098/rstb.2019.0116] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/18/2019] [Indexed: 12/11/2022] Open
Abstract
Tropical forests and coral reefs host a disproportionately large share of global biodiversity and provide ecosystem functions and services used by millions of people. Yet, ongoing climate change is leading to an increase in frequency and magnitude of extreme climatic events in the tropics, which, in combination with other local human disturbances, is leading to unprecedented negative ecological consequences for tropical forests and coral reefs. Here, we provide an overview of how and where climate extremes are affecting the most biodiverse ecosystems on Earth and summarize how interactions between global, regional and local stressors are affecting tropical forest and coral reef systems through impacts on biodiversity and ecosystem resilience. We also discuss some key challenges and opportunities to promote mitigation and adaptation to a changing climate at local and global scales. This article is part of the theme issue 'Climate change and ecosystems: threats, opportunities and solutions'.
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Affiliation(s)
- Filipe M. França
- Embrapa Amazônia Oriental, Trav. Dr. Enéas Pinheiro, s/n, CP 48, 66095-100 Belém, PA, Brazil
- Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ, UK
| | | | - Guadalupe Peralta
- School of Biological Sciences, University of Canterbury, Christchurch, New Zealand
| | | | | | - Jason M. Tylianakis
- School of Biological Sciences, University of Canterbury, Christchurch, New Zealand
| | - Erika Berenguer
- Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ, UK
- Environmental Change Institute, University of Oxford, Oxford OX1 3QY, UK
| | - Alexander C. Lees
- School of Science and the Environment, Manchester Metropolitan University, Manchester, UK
- Cornell Lab of Ornithology, Cornell University, Ithaca, NY 14850, USA
| | - Joice Ferreira
- Embrapa Amazônia Oriental, Trav. Dr. Enéas Pinheiro, s/n, CP 48, 66095-100 Belém, PA, Brazil
- Instituto de Geociências, Universidade Federal do Pará, 66075-110 Belém, PA, Brazil
| | - Júlio Louzada
- Departamento de Biologia, Universidade Federal de Lavras, Lavras 37200-000, MG, Brazil
| | - Jos Barlow
- Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ, UK
- Departamento de Biologia, Universidade Federal de Lavras, Lavras 37200-000, MG, Brazil
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Wall CB, Ritson‐Williams R, Popp BN, Gates RD. Spatial variation in the biochemical and isotopic composition of corals during bleaching and recovery. LIMNOLOGY AND OCEANOGRAPHY 2019; 64:2011-2028. [PMID: 31598010 PMCID: PMC6774332 DOI: 10.1002/lno.11166] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Revised: 12/24/2018] [Accepted: 03/01/2019] [Indexed: 06/01/2023]
Abstract
Ocean warming and the increased prevalence of coral bleaching events threaten coral reefs. However, the biology of corals during and following bleaching events under field conditions is poorly understood. We examined bleaching and postbleaching recovery in Montipora capitata and Porites compressa corals that either bleached or did not bleach during a 2014 bleaching event at three reef locations in Kāne'ohe Bay, O'ahu, Hawai'i. We measured changes in chlorophylls, tissue biomass, and nutritional plasticity using stable isotopes (δ 13C, δ 15N). Coral traits showed significant variation among periods, sites, bleaching conditions, and their interactions. Bleached colonies of both species had lower chlorophyll and total biomass, and while M. capitata chlorophyll and biomass recovered 3 months later, P. compressa chlorophyll recovery was location dependent and total biomass of previously bleached colonies remained low. Biomass energy reserves were not affected by bleaching, instead M. capitata proteins and P. compressa biomass energy and lipids declined over time and P. compressa lipids were site specific during bleaching recovery. Stable isotope analyses did not indicate increased heterotrophic nutrition in bleached colonies of either species, during or after thermal stress. Instead, mass balance calculations revealed that variations in δ 13C values reflect biomass compositional change (i.e., protein : lipid : carbohydrate ratios). Observed δ 15N values reflected spatiotemporal variability in nitrogen sources in both species and bleaching effects on symbiont nitrogen demand in P. compressa. These results highlight the dynamic responses of corals to natural bleaching and recovery and identify the need to consider the influence of biomass composition in the interpretation of isotopic values in corals.
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Affiliation(s)
- Christopher B. Wall
- Hawai‘i Institute of Marine Biology, School of Ocean and Earth Science and Technology, University of Hawai‘i at MānoaKāne‘oheHawai‘i
| | - Raphael Ritson‐Williams
- Hawai‘i Institute of Marine Biology, School of Ocean and Earth Science and Technology, University of Hawai‘i at MānoaKāne‘oheHawai‘i
- Invertebrate Zoology DepartmentCalifornia Academy of SciencesSan FranciscoCalifornia
| | - Brian N. Popp
- Department of Earth SciencesUniversity of Hawai‘i at MānoaHonoluluHawai‘i
| | - Ruth D. Gates
- Hawai‘i Institute of Marine Biology, School of Ocean and Earth Science and Technology, University of Hawai‘i at MānoaKāne‘oheHawai‘i
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Leggat WP, Camp EF, Suggett DJ, Heron SF, Fordyce AJ, Gardner S, Deakin L, Turner M, Beeching LJ, Kuzhiumparambil U, Eakin CM, Ainsworth TD. Rapid Coral Decay Is Associated with Marine Heatwave Mortality Events on Reefs. Curr Biol 2019; 29:2723-2730.e4. [DOI: 10.1016/j.cub.2019.06.077] [Citation(s) in RCA: 57] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Revised: 04/09/2019] [Accepted: 06/25/2019] [Indexed: 12/29/2022]
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35
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Magel JMT, Burns JHR, Gates RD, Baum JK. Effects of bleaching-associated mass coral mortality on reef structural complexity across a gradient of local disturbance. Sci Rep 2019; 9:2512. [PMID: 30792432 PMCID: PMC6385266 DOI: 10.1038/s41598-018-37713-1] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Accepted: 12/04/2018] [Indexed: 11/26/2022] Open
Abstract
Structural complexity underpins the ecological functioning of coral reefs. However, rising ocean temperatures and associated coral bleaching threaten the structural integrity of these important ecosystems. Despite the increased frequency of coral bleaching events, few studies to date have examined changes in three-dimensional (3D) reef structural complexity following severe bleaching. The influence of local stressors on reef complexity also remains poorly understood. In the wake of the 2015-2016 El Niño-induced mass coral bleaching event, we quantified the effects of severe heat stress on 3D reef structural complexity across a gradient of local human disturbance. Using Structure-from-Motion photogrammetry we created 3D reconstructions of permanent reef plots and observed substantial declines in reef structural complexity, measured as surface rugosity and terrain ruggedness, and a detectable loss of habitat volume one year after the bleaching event. 3D reef complexity also declined with increasing levels of human disturbance, and with decreasing densities of branching and massive corals. These findings improve our understanding of the effects of local and global stressors on the structural foundation of coral reef ecosystems. In the face of accelerating climate change, mitigating local stressors may increase reef structural complexity, thereby heightening reef resilience to future bleaching events.
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Affiliation(s)
- Jennifer M T Magel
- Department of Biology, University of Victoria, Victoria, British Columbia, V8P 5C2, Canada.
| | - John H R Burns
- Hawai'i Institute of Marine Biology, University of Hawai'i, Kāne'ohe, Hilo, Hawai'i, 96744, USA.,Marine Science Department, College of Natural and Health Sciences, University of Hawai'i at Hilo, Hilo, Hawai'i, 96720, USA
| | - Ruth D Gates
- Hawai'i Institute of Marine Biology, University of Hawai'i, Kāne'ohe, Hilo, Hawai'i, 96744, USA
| | - Julia K Baum
- Department of Biology, University of Victoria, Victoria, British Columbia, V8P 5C2, Canada.,Hawai'i Institute of Marine Biology, University of Hawai'i, Kāne'ohe, Hilo, Hawai'i, 96744, USA
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Integrating Three-Dimensional Benthic Habitat Characterization Techniques into Ecological Monitoring of Coral Reefs. JOURNAL OF MARINE SCIENCE AND ENGINEERING 2019. [DOI: 10.3390/jmse7020027] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Long-term ecological monitoring of reef fish populations often requires the simultaneous collection of data on benthic habitats in order to account for the effects of these variables on fish assemblage structure. Here, we described an approach to benthic surveys that uses photogrammetric techniques to facilitate the extraction of quantitative metrics for characterization of benthic habitats from the resulting three-dimensional (3D) reconstruction of coral reefs. Out of 92 sites surveyed in the Northwestern Hawaiian Islands, photographs from 85 sites achieved complete alignment and successfully produced 3D reconstructions and digital elevation models (DEMs). Habitat metrics extracted from the DEMs were generally correlated with one another, with the exception of curvature measures, indicating that complexity and curvature measures should be treated separately when quantifying the habitat structure. Fractal dimension D64, calculated by changing resolutions of the DEMs from 1 cm to 64 cm, had the best correlations with other habitat metrics. Fractal dimension was also less affected by changes in orientations of the models compared to surface complexity or slope. These results showed that fractal dimension can be used as a single measure of complexity for the characterization of coral reef habitats. Further investigations into metrics for 3D characterization of habitats should consider relevant spatial scales and focus on obtaining variables that can complement fractal dimension in the characterization of reef habitats.
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Coles SL, Bahr KD, Rodgers KS, May SL, McGowan AE, Tsang A, Bumgarner J, Han JH. Evidence of acclimatization or adaptation in Hawaiian corals to higher ocean temperatures. PeerJ 2018; 6:e5347. [PMID: 30123699 PMCID: PMC6086081 DOI: 10.7717/peerj.5347] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2018] [Accepted: 07/09/2018] [Indexed: 11/22/2022] Open
Abstract
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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Affiliation(s)
- Steve L. Coles
- Bernice Pauahi Bishop Museum, Department of Natural Sciences, Honolulu, Hawai’i, USA
- University of Hawai’i at Mānoa, Hawai’i Institute of Marine Biology, Kāne’ohe, Hawai’i, USA
| | - Keisha D. Bahr
- University of Hawai’i at Mānoa, Hawai’i Institute of Marine Biology, Kāne’ohe, Hawai’i, USA
| | - Ku’ulei S. Rodgers
- University of Hawai’i at Mānoa, Hawai’i Institute of Marine Biology, Kāne’ohe, Hawai’i, USA
| | - Stacie L. May
- University of Hawai’i at Mānoa, Hawai’i Institute of Marine Biology, Kāne’ohe, Hawai’i, USA
| | - Ashley E. McGowan
- University of Hawai’i at Mānoa, Hawai’i Institute of Marine Biology, Kāne’ohe, Hawai’i, USA
| | - Anita Tsang
- University of Hawai’i at Mānoa, Hawai’i Institute of Marine Biology, Kāne’ohe, Hawai’i, USA
| | - Josh Bumgarner
- University of Hawai’i at Mānoa, Hawai’i Institute of Marine Biology, Kāne’ohe, Hawai’i, USA
| | - Ji Hoon Han
- University of Hawai’i at Mānoa, Hawai’i Institute of Marine Biology, Kāne’ohe, Hawai’i, USA
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Influence of Chemotaxis and Swimming Patterns on the Virulence of the Coral Pathogen Vibrio coralliilyticus. J Bacteriol 2018; 200:JB.00791-17. [PMID: 29555697 DOI: 10.1128/jb.00791-17] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2018] [Accepted: 03/11/2018] [Indexed: 02/08/2023] Open
Abstract
Chemotaxis, the directed movement toward or away from a chemical signal, can be essential to bacterial pathogens for locating hosts or avoiding hostile environments. The coral pathogen Vibrio coralliilyticus chemotaxes toward coral mucus; however, chemotaxis has not been experimentally demonstrated to be important for virulence. To further examine this, in-frame mutations were constructed in genes predicted to be important for V. coralliilyticus chemotaxis. Most Vibrio genomes contain multiple homologs of various chemotaxis-related genes, and two paralogs of each for cheB, cheR, and cheA were identified. Based on single mutant analyses, the paralogs cheB2, cheR2, and cheA1 were essential for chemotaxis in laboratory assays. As predicted, the ΔcheA1 and ΔcheR2 strains had a smooth-swimming pattern, while the ΔcheB2 strain displayed a zigzag pattern when observed under light microscopy. However, these mutants, unlike the parent strain, were unable to chemotax toward the known attractants coral mucus, dimethylsulfoniopropionate, and N-acetyl-d-glucosamine. The ΔcheB2 strain and an aflagellate ΔfliG1 strain were avirulent to coral, while the ΔcheA1 and ΔcheR2 strains were hypervirulent (90 to 100% infection within 14 h on average) compared to the wild-type strain (66% infection within 36 h on average). Additionally, the ΔcheA1 and ΔcheR2 strains appeared to better colonize coral fragments than the wild-type strain. These results suggest that although chemotaxis may be involved with infection (the ΔcheB2 strain was avirulent), a smooth-swimming phenotype is important for bacterial colonization and infection. This study provides valuable insight into understanding V. coralliilyticus pathogenesis and how this pathogen may be transmitted between hosts.IMPORTANCE Corals are responsible for creating the immense structures that are essential to reef ecosystems; unfortunately, pathogens like the bacterium Vibrio coralliilyticus can cause fatal infections of reef-building coral species. However, compared to related human pathogens, the mechanisms by which V. coralliilyticus initiates infections and locates new coral hosts are poorly understood. This study investigated the effects of chemotaxis, the directional swimming in response to chemical signals, and bacterial swimming patterns on infection of the coral Montipora capitata Infection experiments with different mutant strains suggested that a smooth-swimming pattern resulted in hypervirulence. These results demonstrate that the role of chemotaxis in coral infection may not be as straightforward as previously hypothesized and provide valuable insight into V. coralliilyticus pathogenesis.
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Monroe AA, Ziegler M, Roik A, Röthig T, Hardenstine RS, Emms MA, Jensen T, Voolstra CR, Berumen ML. In situ observations of coral bleaching in the central Saudi Arabian Red Sea during the 2015/2016 global coral bleaching event. PLoS One 2018; 13:e0195814. [PMID: 29672556 PMCID: PMC5908266 DOI: 10.1371/journal.pone.0195814] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Accepted: 04/01/2018] [Indexed: 11/18/2022] Open
Abstract
Coral bleaching continues to be one of the most devastating and immediate impacts of climate change on coral reef ecosystems worldwide. In 2015, a major bleaching event was declared as the "3rd global coral bleaching event" by the United States National Oceanic and Atmospheric Administration, impacting a large number of reefs in every major ocean. The Red Sea was no exception, and we present herein in situ observations of the status of coral reefs in the central Saudi Arabian Red Sea from September 2015, following extended periods of high temperatures reaching upwards of 32.5°C in our study area. We examined eleven reefs using line-intercept transects at three different depths, including all reefs that were surveyed during a previous bleaching event in 2010. Bleaching was most prevalent on inshore reefs (55.6% ± 14.6% of live coral cover exhibited bleaching) and on shallower transects (41% ± 10.2% of live corals surveyed at 5m depth) within reefs. Similar taxonomic groups (e.g., Agariciidae) were affected in 2015 and in 2010. Most interestingly, Acropora and Porites had similar bleaching rates (~30% each) and similar relative coral cover (~7% each) across all reefs in 2015. Coral genera with the highest levels of bleaching (>60%) were also among the rarest (<1% of coral cover) in 2015. While this bodes well for the relative retention of coral cover, it may ultimately lead to decreased species richness, often considered an important component of a healthy coral reef. The resultant long-term changes in these coral reef communities remain to be seen.
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Affiliation(s)
- Alison A. Monroe
- Red Sea Research Center, Division of Biological and Environmental Science and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
- * E-mail:
| | - Maren Ziegler
- Red Sea Research Center, Division of Biological and Environmental Science and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
| | - Anna Roik
- Red Sea Research Center, Division of Biological and Environmental Science and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
- Marine Microbiology, GEOMAR Helmholtz Center for Ocean Research Kiel Düsternbrooker Weg 20, Kiel, Germany
| | - Till Röthig
- Red Sea Research Center, Division of Biological and Environmental Science and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
- The Swire Institute of Marine Science, The University of Hong Kong, Hong Kong, China
| | - Royale S. Hardenstine
- Red Sea Research Center, Division of Biological and Environmental Science and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
| | - Madeleine A. Emms
- Red Sea Research Center, Division of Biological and Environmental Science and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
| | - Thor Jensen
- Red Sea Research Center, Division of Biological and Environmental Science and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
| | - Christian R. Voolstra
- Red Sea Research Center, Division of Biological and Environmental Science and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
| | - Michael L. Berumen
- Red Sea Research Center, Division of Biological and Environmental Science and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
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Climate Variability and Change: Monitoring Data and Evidence for Increased Coral Bleaching Stress. ECOLOGICAL STUDIES 2018. [DOI: 10.1007/978-3-319-75393-5_4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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Ferrari R, Figueira WF, Pratchett MS, Boube T, Adam A, Kobelkowsky-Vidrio T, Doo SS, Atwood TB, Byrne M. 3D photogrammetry quantifies growth and external erosion of individual coral colonies and skeletons. Sci Rep 2017; 7:16737. [PMID: 29196651 PMCID: PMC5711843 DOI: 10.1038/s41598-017-16408-z] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2017] [Accepted: 11/01/2017] [Indexed: 11/21/2022] Open
Abstract
Growth and contraction of ecosystem engineers, such as trees, influence ecosystem structure and function. On coral reefs, methods to measure small changes in the structure of microhabitats, driven by growth of coral colonies and contraction of skeletons, are extremely limited. We used 3D reconstructions to quantify changes in the external structure of coral colonies of tabular Acropora spp., the dominant habitat-forming corals in shallow exposed reefs across the Pacific. The volume and surface area of live colonies increased by 21% and 22%, respectively, in 12 months, corresponding to a mean annual linear extension of 5.62 cm yr-1 (±1.81 SE). The volume and surface area of dead skeletons decreased by 52% and 47%, respectively, corresponding to a mean decline in linear extension of -29.56 cm yr-1 (±7.08 SE), which accounted for both erosion and fragmentation of dead colonies. This is the first study to use 3D photogrammetry to assess fine-scale structural changes of entire individual colonies in situ, quantifying coral growth and contraction. The high-resolution of the technique allows for detection of changes on reef structure faster than other non-intrusive approaches. These results improve our capacity to measure the drivers underpinning ecosystem biodiversity, status and trajectory.
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Affiliation(s)
- Renata Ferrari
- School of Life and Environmental Sciences, Edgeworth David Building, Science Road, The University of Sydney, Sydney, NSW 2006, Australia.
- Australian Institute of Marine Sciences, PMB No. 3, Townsville, Queensland, 4810, Australia.
| | - Will F Figueira
- School of Life and Environmental Sciences, Edgeworth David Building, Science Road, The University of Sydney, Sydney, NSW 2006, Australia
| | - Morgan S Pratchett
- ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, Australia
| | - Tatiana Boube
- School of Life and Environmental Sciences, Edgeworth David Building, Science Road, The University of Sydney, Sydney, NSW 2006, Australia
| | - Arne Adam
- School of Life and Environmental Sciences, Edgeworth David Building, Science Road, The University of Sydney, Sydney, NSW 2006, Australia
| | - Tania Kobelkowsky-Vidrio
- School of Life and Environmental Sciences, Edgeworth David Building, Science Road, The University of Sydney, Sydney, NSW 2006, Australia
| | - Steve S Doo
- School of Life and Environmental Sciences, Edgeworth David Building, Science Road, The University of Sydney, Sydney, NSW 2006, Australia
| | - Trisha Brooke Atwood
- Department of Watershed Sciences and Ecology Center, Utah State University, Logan, UT, USA
- Global Change Institute, The University of Queensland, St. Lucia, QLD, Australia
| | - Maria Byrne
- School of Life and Environmental Sciences, Edgeworth David Building, Science Road, The University of Sydney, Sydney, NSW 2006, Australia
- School of Medical Sciences, The University of Sydney, Sydney, NSW 2006, Australia
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