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Lin YV, Château PA, Nozawa Y, Wei CL, Wunderlich RF, Denis V. Drivers of coastal benthic communities in a complex environmental setting. MARINE POLLUTION BULLETIN 2024; 203:116462. [PMID: 38749153 DOI: 10.1016/j.marpolbul.2024.116462] [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: 01/22/2024] [Revised: 05/02/2024] [Accepted: 05/02/2024] [Indexed: 06/06/2024]
Abstract
Analyzing the environmental factors affecting benthic communities in coastal areas is crucial for uncovering key factors that require conservation action. Here, we collected benthic and environmental (physical-chemical-historical and land-based) data for 433 transects in Taiwan. Using a k-means approach, five communities dominated by crustose coralline algae, turfs, stony corals, digitate, or bushy octocorals were first delineated. Conditional random forest models then identified physical, chemical, and land-based factors (e.g., light intensity, nitrite, and population density) relevant to community delineation and occurrence. Historical factors, including typhoons and temperature anomalies, had only little effect. The prevalent turf community correlated positively with chemical and land-based drivers, which suggests that anthropogenic impacts are causing a benthic homogenization. This mechanism may mask the effects of climate disturbances and regional differentiation of benthic assemblages. Consequently, management of nutrient enrichment and terrestrial runoff is urgently needed to improve community resilience in Taiwan amidst increasing challenges of climate change.
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Affiliation(s)
- Yuting Vicky Lin
- Institute of Oceanography, National Taiwan University, Taipei 10617, Taiwan
| | - Pierre-Alexandre Château
- Department of Marine Environment and Engineering, National Sun Yat-Sen University, Kaohsiung 80420, Taiwan
| | - Yoko Nozawa
- Tropical Biosphere Research Center, University of the Ryukyus, Okinawa 905-0227, Japan; Biodiversity Research Center, Academia Sinica, Taipei 11529, Taiwan; Department of Marine Science, Faculty of Fisheries and Marine Science, Universitas Diponegoro, Semarang 50275, Indonesia
| | - Chih-Lin Wei
- Institute of Oceanography, National Taiwan University, Taipei 10617, Taiwan
| | - Rainer Ferdinand Wunderlich
- Department of Bioenvironmental Systems Engineering, National Taiwan University, Taipei 10617, Taiwan; INRAE, UR EABX, 33612 Cestas, France
| | - Vianney Denis
- Institute of Oceanography, National Taiwan University, Taipei 10617, Taiwan.
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2
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Aji LP, Maas DL, Capriati A, Ahmad A, de Leeuw C, Becking LE. Shifts in dominance of benthic communities along a gradient of water temperature and turbidity in tropical coastal ecosystems. PeerJ 2024; 12:e17132. [PMID: 38666078 PMCID: PMC11044884 DOI: 10.7717/peerj.17132] [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: 11/20/2023] [Accepted: 02/27/2024] [Indexed: 04/28/2024] Open
Abstract
Tropical coastal benthic communities will change in species composition and relative dominance due to global (e.g., increasing water temperature) and local (e.g., increasing terrestrial influence due to land-based activity) stressors. This study aimed to gain insight into possible trajectories of coastal benthic assemblages in Raja Ampat, Indonesia, by studying coral reefs at varying distances from human activities and marine lakes with high turbidity in three temperature categories (<31 °C, 31-32 °C, and >32 °C). The benthic community diversity and relative coverage of major benthic groups were quantified via replicate photo transects. The composition of benthic assemblages varied significantly among the reef and marine lake habitats. The marine lakes <31 °C contained hard coral, crustose coralline algae (CCA), and turf algae with coverages similar to those found in the coral reefs (17.4-18.8% hard coral, 3.5-26.3% CCA, and 15-15.5% turf algae, respectively), while the higher temperature marine lakes (31-32 °C and >32 °C) did not harbor hard coral or CCA. Benthic composition in the reefs was significantly influenced by geographic distance among sites but not by human activity or depth. Benthic composition in the marine lakes appeared to be structured by temperature, salinity, and degree of connection to the adjacent sea. Our results suggest that beyond a certain temperature (>31 °C), benthic communities shift away from coral dominance, but new outcomes of assemblages can be highly distinct, with a possible varied dominance of macroalgae, benthic cyanobacterial mats, or filter feeders such as bivalves and tubeworms. This study illustrates the possible use of marine lake model systems to gain insight into shifts in the benthic community structure of tropical coastal ecosystems if hard corals are no longer dominant.
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Affiliation(s)
- Ludi Parwadani Aji
- Wageningen University and Research, Wageningen, The Netherlands
- Naturalis Biodiversity Center, Leiden, The Netherlands
- Research Center for Oceanography, National Research and Innovation Agency, Jakarta, Indonesia
| | | | | | | | | | - Leontine Elisabeth Becking
- Wageningen University and Research, Wageningen, The Netherlands
- Naturalis Biodiversity Center, Leiden, The Netherlands
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3
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Klein SG, Roch C, Duarte CM. Systematic review of the uncertainty of coral reef futures under climate change. Nat Commun 2024; 15:2224. [PMID: 38472196 DOI: 10.1038/s41467-024-46255-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Accepted: 02/19/2024] [Indexed: 03/14/2024] Open
Abstract
Climate change impact syntheses, such as those by the Intergovernmental Panel on Climate Change, consistently assert that limiting global warming to 1.5 °C is unlikely to safeguard most of the world's coral reefs. This prognosis is primarily based on a small subset of available models that apply similar 'excess heat' threshold methodologies. Our systematic review of 79 articles projecting coral reef responses to climate change revealed five main methods. 'Excess heat' models constituted one third (32%) of all studies but attracted a disproportionate share (68%) of citations in the field. Most methods relied on deterministic cause-and-effect rules rather than probabilistic relationships, impeding the field's ability to estimate uncertainty. To synthesize the available projections, we aimed to identify models with comparable outputs. However, divergent choices in model outputs and scenarios limited the analysis to a fraction of available studies. We found substantial discrepancies in the projected impacts, indicating that the subset of articles serving as a basis for climate change syntheses may project more severe consequences than other studies and methodologies. Drawing on insights from other fields, we propose methods to incorporate uncertainty into deterministic modeling approaches and propose a multi-model ensemble approach to generating probabilistic projections for coral reef futures.
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Affiliation(s)
- Shannon G Klein
- Marine Science Program, Biological and Environmental Science and Engineering Division (BESE), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Kingdom of Saudi Arabia.
- Red Sea Research Center (RSRC), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Kingdom of Saudi Arabia.
- Computational Bioscience Research Center (CBRC), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Kingdom of Saudi Arabia.
| | - Cassandra Roch
- Marine Science Program, Biological and Environmental Science and Engineering Division (BESE), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Kingdom of Saudi Arabia
- Red Sea Research Center (RSRC), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Kingdom of Saudi Arabia
- Computational Bioscience Research Center (CBRC), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Kingdom of Saudi Arabia
| | - Carlos M Duarte
- Marine Science Program, Biological and Environmental Science and Engineering Division (BESE), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Kingdom of Saudi Arabia.
- Red Sea Research Center (RSRC), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Kingdom of Saudi Arabia.
- Computational Bioscience Research Center (CBRC), King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Kingdom of Saudi Arabia.
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4
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Sannassy Pilly S, Roche RC, Richardson LE, Turner JR. Depth variation in benthic community response to repeated marine heatwaves on remote Central Indian Ocean reefs. ROYAL SOCIETY OPEN SCIENCE 2024; 11:231246. [PMID: 38545610 PMCID: PMC10966399 DOI: 10.1098/rsos.231246] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/22/2023] [Revised: 12/01/2023] [Accepted: 02/21/2024] [Indexed: 04/26/2024]
Abstract
Coral reefs are increasingly impacted by climate-induced warming events. However, there is limited empirical evidence on the variation in the response of shallow coral reef communities to thermal stress across depths. Here, we assess depth-dependent changes in coral reef benthic communities following successive marine heatwaves from 2015 to 2017 across a 5-25 m depth gradient in the remote Chagos Archipelago, Central Indian Ocean. Our analyses show an overall decline in hard and soft coral cover and an increase in crustose coralline algae, sponge and reef pavement following successive marine heatwaves on the remote reef system. Our findings indicate that the changes in benthic communities in response to elevated seawater temperatures varied across depths. We found greater changes in benthic group cover at shallow depths (5-15 m) compared with deeper zones (15-25 m). The loss of hard coral cover was better predicted by initial thermal stress, while the loss of soft coral was associated with repeated thermal stress following successive warming events. Our study shows that benthic communities extending to 25 m depth were impacted by successive marine heatwaves, supporting concerns about the resilience of shallow coral reef communities to increasingly severe climate-driven warming events.
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Affiliation(s)
| | - Ronan C. Roche
- School of Ocean Sciences, Bangor University, BangorLL59 5AB, UK
| | | | - John R. Turner
- School of Ocean Sciences, Bangor University, BangorLL59 5AB, UK
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5
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Mihalitsis M, Wainwright PC. Feeding kinematics of a surgeonfish reveal novel functions and relationships to reef substrata. Commun Biol 2024; 7:13. [PMID: 38172236 PMCID: PMC10764775 DOI: 10.1038/s42003-023-05696-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Accepted: 12/12/2023] [Indexed: 01/05/2024] Open
Abstract
Biting to obtain attached benthic prey characterizes a large number of fish species on coral reefs, and is a feeding mode that contributes to important ecosystem functions. We use high-speed video to reveal the mechanisms used by a surgeonfish, Acanthurus leucosternon, to detach algae. After gripping algae in its jaws, the species pulls it by ventrally rotating both the head and the closed jaws, in a novel use of the intra-mandibular joint. These motions remain in the plane of the fish, reducing the use of a lateral head flick to detach the algae. The novel ability to bite and pull algae off the substrate without bending the body laterally minimizes exposure to high water flows, and may be an adaptation to feeding in challenging reef habitats such as the crest and flat. Therefore, our results could potentially represent a key milestone in the evolutionary history of coral reef trophodynamics.
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Affiliation(s)
- Michalis Mihalitsis
- Department of Evolution and Ecology, University of California, Davis, CA, 95616, USA.
| | - Peter C Wainwright
- Department of Evolution and Ecology, University of California, Davis, CA, 95616, USA
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6
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Walker AS, Kratochwill CA, van Woesik R. Past disturbances and local conditions influence the recovery rates of coral reefs. GLOBAL CHANGE BIOLOGY 2024; 30:e17112. [PMID: 38273580 DOI: 10.1111/gcb.17112] [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: 08/09/2023] [Revised: 11/28/2023] [Accepted: 11/28/2023] [Indexed: 01/27/2024]
Abstract
Corals are being increasingly subjected to marine heatwaves. Theory suggests that increasing the intensity of disturbances reduces recovery rates, which inspired us to examine the recovery rates of coral cover following marine heatwaves, cyclones, and other disturbances at 1921 study sites, in 58 countries and three oceans, from 1977 to 2020. In the Atlantic Ocean, coral cover has decreased fourfold since the 1970s, and recovery rates following disturbances have been relatively slow, except in the Antilles. By contrast, reefs in the Pacific and Indian Oceans have maintained coral cover and recovery rates over time. There were positive relationships between rates of coral recovery and prior cyclone and heatwave frequency, and negative relationships between rates of coral recovery and macroalgae cover and distance to shore. A recent increase in the variance in recovery rates in some ecoregions of the Pacific and Indian Oceans suggests that some reefs in those ecoregions may be approaching a phase shift. While marine heatwaves are increasing in intensity and frequency, our results suggest that regional and local conditions influence coral recovery rates, and therefore, effective local management efforts can help reefs recover from disturbances.
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Affiliation(s)
- Andrew S Walker
- Institute for Global Ecology, Florida Institute of Technology, Melbourne, Florida, USA
| | - Chelsey A Kratochwill
- Institute for Global Ecology, Florida Institute of Technology, Melbourne, Florida, USA
| | - Robert van Woesik
- Institute for Global Ecology, Florida Institute of Technology, Melbourne, Florida, USA
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7
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Morais J, Tebbett SB, Morais RA, Bellwood DR. Natural recovery of corals after severe disturbance. Ecol Lett 2024; 27:e14332. [PMID: 37850584 DOI: 10.1111/ele.14332] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 09/28/2023] [Accepted: 10/06/2023] [Indexed: 10/19/2023]
Abstract
Ecosystem recovery from human-induced disturbances, whether through natural processes or restoration, is occurring worldwide. Yet, recovery dynamics, and their implications for broader ecosystem management, remain unclear. We explored recovery dynamics using coral reefs as a case study. We tracked the fate of 809 individual coral recruits that settled after a severe bleaching event at Lizard Island, Great Barrier Reef. Recruited Acropora corals, first detected in 2020, grew to coral cover levels that were equivalent to global average coral cover within just 2 years. Furthermore, we found that just 11.5 Acropora recruits per square meter were sufficient to reach this cover within 2 years. However, wave exposure, growth form and colony density had a marked effect on recovery rates. Our results underscore the importance of considering natural recovery in management and restoration and highlight how lessons learnt from reef recovery can inform our understanding of recovery dynamics in high-diversity climate-disturbed ecosystems.
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Affiliation(s)
- Juliano Morais
- Research Hub for Coral Reef Ecosystem Functions and College of Science and Engineering, James Cook University, Townsville, Queensland, Australia
| | - Sterling B Tebbett
- Research Hub for Coral Reef Ecosystem Functions and College of Science and Engineering, James Cook University, Townsville, Queensland, Australia
| | - Renato A Morais
- Research Hub for Coral Reef Ecosystem Functions and College of Science and Engineering, James Cook University, Townsville, Queensland, Australia
- Paris Sciences et Lettres Université, École Pratique des Hautes Études, EPHE-UPVD-CNRS, UAR 3278 CRIOBE, University of Perpignan, Perpignan, France
| | - David R Bellwood
- Research Hub for Coral Reef Ecosystem Functions and College of Science and Engineering, James Cook University, Townsville, Queensland, Australia
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8
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Benkwitt CE, D'Angelo C, Dunn RE, Gunn RL, Healing S, Mardones ML, Wiedenmann J, Wilson SK, Graham NAJ. Seabirds boost coral reef resilience. SCIENCE ADVANCES 2023; 9:eadj0390. [PMID: 38055814 DOI: 10.1126/sciadv.adj0390] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Accepted: 11/03/2023] [Indexed: 12/08/2023]
Abstract
Global climate change threatens tropical coral reefs, yet local management can influence resilience. While increasing anthropogenic nutrients reduce coral resistance and recovery, it is unknown how the loss, or restoration, of natural nutrient flows affects reef recovery. Here, we test how natural seabird-derived nutrient subsidies, which are threatened by invasive rats, influence the mechanisms and patterns of reef recovery following an extreme marine heatwave using multiyear field experiments, repeated surveys, and Bayesian modeling. Corals transplanted from rat to seabird islands quickly assimilated seabird-derived nutrients, fully acclimating to new nutrient conditions within 3 years. Increased seabird-derived nutrients, in turn, caused a doubling of coral growth rates both within individuals and across entire reefs. Seabirds were also associated with faster recovery time of Acropora coral cover (<4 years) and more dynamic recovery trajectories of entire benthic communities. We conclude that restoring seabird populations and associated nutrient pathways may foster greater coral reef resilience through enhanced growth and recovery rates of corals.
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Affiliation(s)
| | - Cecilia D'Angelo
- Coral Reef Laboratory, School of Ocean and Earth Science, University of Southampton, Southampton SO143ZH, UK
| | - Ruth E Dunn
- Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ, UK
- The Lyell Centre, Heriot-Watt University, Edinburgh EH14 4AS, UK
| | - Rachel L Gunn
- Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ, UK
- Animal Evolutionary Ecology, Institute of Evolution and Ecology, University of Tübingen, Auf Der Morgenstelle 28, 72076 Tübingen, Germany
| | - Samuel Healing
- Lancaster Environment Centre, Lancaster University, Lancaster LA1 4YQ, UK
| | - M Loreto Mardones
- Coral Reef Laboratory, School of Ocean and Earth Science, University of Southampton, Southampton SO143ZH, UK
| | - Joerg Wiedenmann
- Coral Reef Laboratory, School of Ocean and Earth Science, University of Southampton, Southampton SO143ZH, UK
| | - Shaun K Wilson
- Australian Institute of Marine Science, Indian Ocean Marine Research Centre, Crawley, WA 6009, Australia
- University of Western Australia, UWA Oceans Institute, Crawley, WA 6009, Australia
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9
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Zhang Y, Gantt SE, Keister EF, Elder H, Kolodziej G, Aguilar C, Studivan MS, Williams DE, Kemp DW, Manzello DP, Enochs IC, Kenkel CD. Performance of Orbicella faveolata larval cohorts does not align with previously observed thermal tolerance of adult source populations. GLOBAL CHANGE BIOLOGY 2023; 29:6591-6605. [PMID: 37846617 DOI: 10.1111/gcb.16977] [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: 06/27/2023] [Revised: 09/11/2023] [Accepted: 09/13/2023] [Indexed: 10/18/2023]
Abstract
Orbicella faveolata, commonly known as the mountainous star coral, is a dominant reef-building species in the Caribbean, but populations have suffered sharp declines since the 1980s due to repeated bleaching and disease-driven mortality. Prior research has shown that inshore adult O. faveolata populations in the Florida Keys are able to maintain high coral cover and recover from bleaching faster than their offshore counterparts. However, whether this origin-specific variation in thermal resistance is heritable remains unclear. To address this knowledge gap, we produced purebred and hybrid larval crosses from O. faveolata gametes collected at two distinct reefs in the Upper Florida Keys, a nearshore site (Cheeca Rocks, CR) and an offshore site (Horseshoe Reef, HR), in two different years (2019, 2021). We then subjected these aposymbiotic larvae to severe (36°C) and moderate (32°C) heat challenges to quantify their thermal tolerance. Contrary to our expectation based on patterns of adult thermal tolerance, HR purebred larvae survived better and exhibited gene expression profiles that were less driven by stress response under elevated temperature compared to purebred CR and hybrid larvae. One potential explanation could be the compromised reproductive output of CR adult colonies due to repeated summer bleaching events in 2018 and 2019, as gametes originating from CR in 2019 contained less storage lipids than those from HR. These findings provide an important counter-example to the current selective breeding paradigm, that more tolerant parents will yield more tolerant offspring, and highlight the importance of adopting a holistic approach when evaluating larval quality for conservation and restoration purposes.
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Affiliation(s)
- Yingqi Zhang
- Department of Biological Sciences, University of Southern California, Los Angeles, California, USA
| | - Shelby E Gantt
- Department of Biology, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Elise F Keister
- Department of Biology, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Holland Elder
- Department of Biological Sciences, University of Southern California, Los Angeles, California, USA
| | - Graham Kolodziej
- University of Miami, Cooperative Institute for Marine and Atmospheric Studies, Miami, Florida, USA
- Ocean Chemistry and Ecosystems Division, NOAA Atlantic Oceanographic and Meteorological Laboratory, Miami, Florida, USA
| | - Catalina Aguilar
- University of Miami, Cooperative Institute for Marine and Atmospheric Studies, Miami, Florida, USA
- Ocean Chemistry and Ecosystems Division, NOAA Atlantic Oceanographic and Meteorological Laboratory, Miami, Florida, USA
| | - Michael S Studivan
- University of Miami, Cooperative Institute for Marine and Atmospheric Studies, Miami, Florida, USA
- Ocean Chemistry and Ecosystems Division, NOAA Atlantic Oceanographic and Meteorological Laboratory, Miami, Florida, USA
| | - Dana E Williams
- Population and Ecosystem Monitoring Division, NOAA Southeast Fisheries Science Center, Miami, Florida, USA
| | - Dustin W Kemp
- Department of Biology, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Derek P Manzello
- Coral Reef Watch, Satellite Oceanography and Climatology Division, Center for Satellite Applications and Research, U.S. National Oceanic and Atmospheric Administration, College Park, Maryland, USA
| | - Ian C Enochs
- Ocean Chemistry and Ecosystems Division, NOAA Atlantic Oceanographic and Meteorological Laboratory, Miami, Florida, USA
| | - Carly D Kenkel
- Department of Biological Sciences, University of Southern California, Los Angeles, California, USA
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10
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Tebbett SB, Schlaefer JA, Bowden CL, Collins WP, Hemingson CR, Ling SD, Morais J, Morais RA, Siqueira AC, Streit RP, Swan S, Bellwood DR. Bio-physical determinants of sediment accumulation on an offshore coral reef: A snapshot study. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 895:165188. [PMID: 37385494 DOI: 10.1016/j.scitotenv.2023.165188] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Revised: 06/15/2023] [Accepted: 06/26/2023] [Indexed: 07/01/2023]
Abstract
Sediments are found on all coral reefs around the globe. However, the amount of sediment in different reservoirs, and the rates at which sediments move between reservoirs, can shape the biological functioning of coral reefs. Unfortunately, relatively few studies have examined reef sediment dynamics, and associated bio-physical drivers, simultaneously over matching spatial and temporal scales. This has led to a partial understanding of how sediments and living reef systems are connected, especially on clear-water offshore reefs. To address this problem, four sediment reservoirs/sedimentary processes and three bio-physical drivers were quantified across seven different reef habitats/depths at Lizard Island, an exposed mid-shelf reef on the Great Barrier Reef. Even in this clear-water reef location a substantial load of suspended sediment passed over the reef; a load theoretically capable of replacing the entire standing stock of on-reef turf sediments in just 8 h. However, quantification of actual sediment deposition suggested that just 2 % of this passing sediment settled on the reef. The data also revealed marked spatial incongruence in sediment deposition (sediment trap data) and accumulation (TurfPod data) across the reef profile, with the flat and back reef emerging as key areas of both deposition and accumulation. By contrast, the shallow windward reef crest was an area of deposition but had a limited capacity for sediment accumulation. These cross-reef patterns related to wave energy and reef geomorphology, with low sediment accumulation on the ecologically important reef crest aligning with substantial wave energy. These findings reveal a disconnect between patterns of sediment deposition and accumulation on the benthos, with the 'post-settlement' fate of sediments dependent on local hydrodynamic conditions. From an ecological perspective, the data suggests key contextual constraints (wave energy and reef geomorphology) may predispose some reefs or reef areas to high-load turf sediment regimes.
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Affiliation(s)
- Sterling B Tebbett
- Research Hub for Coral Reef Ecosystem Functions, College of Science and Engineering, James Cook University, Townsville, Queensland 4811, Australia.
| | - Jodie A Schlaefer
- Research Hub for Coral Reef Ecosystem Functions, College of Science and Engineering, James Cook University, Townsville, Queensland 4811, Australia; Commonwealth Scientific and Industrial Research Organisation (CSIRO), Environment, Townsville, Queensland, 4811, Australia
| | - Casey L Bowden
- Research Hub for Coral Reef Ecosystem Functions, College of Science and Engineering, James Cook University, Townsville, Queensland 4811, Australia
| | - William P Collins
- Research Hub for Coral Reef Ecosystem Functions, College of Science and Engineering, James Cook University, Townsville, Queensland 4811, Australia
| | - Christopher R Hemingson
- Research Hub for Coral Reef Ecosystem Functions, College of Science and Engineering, James Cook University, Townsville, Queensland 4811, Australia; Department of Marine Science, The University of Texas at Austin, Marine Science Institute, Port Aransas, TX, USA
| | - Scott D Ling
- Institute for Marine and Antarctic Studies, University of Tasmania, Hobart 7001, Australia
| | - Juliano Morais
- Research Hub for Coral Reef Ecosystem Functions, College of Science and Engineering, James Cook University, Townsville, Queensland 4811, Australia
| | - Renato A Morais
- Research Hub for Coral Reef Ecosystem Functions, College of Science and Engineering, James Cook University, Townsville, Queensland 4811, Australia; Paris Sciences et Lettres Université, École Pratique des Hautes Études, EPHE-UPVD-CNRS, USR 3278 CRIOBE, University of Perpignan, Perpignan, France
| | - Alexandre C Siqueira
- Research Hub for Coral Reef Ecosystem Functions, College of Science and Engineering, James Cook University, Townsville, Queensland 4811, Australia
| | - Robert P Streit
- Research Hub for Coral Reef Ecosystem Functions, College of Science and Engineering, James Cook University, Townsville, Queensland 4811, Australia
| | - Sam Swan
- Research Hub for Coral Reef Ecosystem Functions, College of Science and Engineering, James Cook University, Townsville, Queensland 4811, Australia
| | - David R Bellwood
- Research Hub for Coral Reef Ecosystem Functions, College of Science and Engineering, James Cook University, Townsville, Queensland 4811, Australia
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11
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Schoepf V, Baumann JH, Barshis DJ, Browne NK, Camp EF, Comeau S, Cornwall CE, Guzmán HM, Riegl B, Rodolfo-Metalpa R, Sommer B. Corals at the edge of environmental limits: A new conceptual framework to re-define marginal and extreme coral communities. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 884:163688. [PMID: 37105476 DOI: 10.1016/j.scitotenv.2023.163688] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Revised: 04/14/2023] [Accepted: 04/19/2023] [Indexed: 05/07/2023]
Abstract
The worldwide decline of coral reefs has renewed interest in coral communities at the edge of environmental limits because they have the potential to serve as resilience hotspots and climate change refugia, and can provide insights into how coral reefs might function in future ocean conditions. These coral communities are often referred to as marginal or extreme but few definitions exist and usage of these terms has therefore been inconsistent. This creates significant challenges for categorising these often poorly studied communities and synthesising data across locations. Furthermore, this impedes our understanding of how coral communities can persist at the edge of their environmental limits and the lessons they provide for future coral reef survival. Here, we propose that marginal and extreme coral communities are related but distinct and provide a novel conceptual framework to redefine them. Specifically, we define coral reef extremeness solely based on environmental conditions (i.e., large deviations from optimal conditions in terms of mean and/or variance) and marginality solely based on ecological criteria (i.e., altered community composition and/or ecosystem functioning). This joint but independent assessment of environmental and ecological criteria is critical to avoid common pitfalls where coral communities existing outside the presumed optimal conditions for coral reef development are automatically considered inferior to coral reefs in more traditional settings. We further evaluate the differential potential of marginal and extreme coral communities to serve as natural laboratories, resilience hotspots and climate change refugia, and discuss strategies for their conservation and management as well as priorities for future research. Our new classification framework provides an important tool to improve our understanding of how corals can persist at the edge of their environmental limits and how we can leverage this knowledge to optimise strategies for coral reef conservation, restoration and management in a rapidly changing ocean.
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Affiliation(s)
- Verena Schoepf
- Department of Freshwater and Marine Ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Amsterdam, the Netherlands; UWA Oceans Institute, University of Western Australia, Perth, Western Australia, Australia.
| | - Justin H Baumann
- Department of Biology, Mount Holyoke College, South Hadley, MA, USA
| | - Daniel J Barshis
- Department of Biological Sciences, Old Dominion University, Norfolk, VA, USA
| | - Nicola K Browne
- School of Molecular and Life Sciences, Curtin University, Perth, Western Australia, Australia
| | - Emma F Camp
- Climate Change Cluster, University of Technology Sydney, Sydney, New South Wales, Australia
| | - Steeve Comeau
- Sorbonne Université, CNRS-INSU, Laboratoire d'Océanographie de Villefranche, Villefranche-sur-mer, France
| | - Christopher E Cornwall
- School of Biological Sciences and Coastal People: Southern Skies, Victoria University of Wellington, Wellington, New Zealand
| | - Héctor M Guzmán
- Smithsonian Tropical Research Institute, Panama, Republic of Panama
| | - Bernhard Riegl
- Department of Marine and Environmental Sciences, Halmos College of Arts and Sciences, Nova Southeastern University, Dania Beach, FL, USA
| | - Riccardo Rodolfo-Metalpa
- ENTROPIE, IRD, Université de la Réunion, CNRS, IFREMER, Université de Nouvelle-Calédonie, Nouméa, New Caledonia; Labex ICONA, International CO(2) Natural Analogues Network, Japan
| | - Brigitte Sommer
- School of Life Sciences, University of Technology Sydney, Sydney, New South Wales, Australia; School of Life and Environmental Sciences, The University of Sydney, Sydney, New South Wales, Australia
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Holmes MJ, Lewis RJ. Model of the Origin of a Ciguatoxic Grouper ( Plectropomus leopardus). Toxins (Basel) 2023; 15:toxins15030230. [PMID: 36977121 PMCID: PMC10055633 DOI: 10.3390/toxins15030230] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 03/16/2023] [Accepted: 03/16/2023] [Indexed: 03/30/2023] Open
Abstract
Published data were used to model the transfer of ciguatoxins (CTX) across three trophic levels of a marine food chain on the Great Barrier Reef (GBR), Australia, to produce a mildly toxic common coral trout (Plectropomus leopardus), one of the most targeted food fishes on the GBR. Our model generated a 1.6 kg grouper with a flesh concentration of 0.1 µg/kg of Pacific-ciguatoxin-1 (P-CTX-1 = CTX1B) from 1.1 to 4.3 µg of P-CTX-1 equivalents (eq.) entering the food chain from 0.7 to 2.7 million benthic dinoflagellates (Gambierdiscus sp.) producing 1.6 pg/cell of the P-CTX-1 precursor, P-CTX-4B (CTX4B). We simulated the food chain transfer of ciguatoxins via surgeonfishes by modelling Ctenochaetus striatus feeding on turf algae. A C. striatus feeding on ≥1000 Gambierdiscus/cm2 of turf algae accumulates sufficient toxin in <2 days that when preyed on, produces a 1.6 kg common coral trout with a flesh concentration of 0.1 µg/kg P-CTX-1. Our model shows that even transient blooms of highly ciguatoxic Gambierdiscus can generate ciguateric fishes. In contrast, sparse cell densities of ≤10 Gambierdiscus/cm2 are unlikely to pose a significant risk, at least in areas where the P-CTX-1 family of ciguatoxins predominate. The ciguatera risk from intermediate Gambierdiscus densities (~100 cells/cm2) is more difficult to assess, as it requires feeding times for surgeonfish (~4-14 days) that overlap with turnover rates of turf algae that are grazed by herbivorous fishes, at least in regions such as the GBR, where stocks of herbivorous fishes are not impacted by fishing. We use our model to explore how the duration of ciguatoxic Gambierdiscus blooms, the type of ciguatoxins they produce, and fish feeding behaviours can produce differences in relative toxicities between trophic levels. Our simple model indicates thresholds for the design of risk and mitigation strategies for ciguatera and the variables that can be manipulated to explore alternate scenarios for the accumulation and transfer of P-CTX-1 analogues through marine food chains and, potentially, for other ciguatoxins in other regions, as more data become available.
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Affiliation(s)
- Michael J Holmes
- Institute for Molecular Bioscience, The University of Queensland, Brisbane 4072, Australia
| | - Richard J Lewis
- Institute for Molecular Bioscience, The University of Queensland, Brisbane 4072, Australia
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