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Dellisanti W, Zhang Q, Ferrier-Pagès C, Kühl M. Contrasting effects of increasing dissolved iron on photosynthesis and O 2 availability in the gastric cavity of two Mediterranean corals. PeerJ 2024; 12:e17259. [PMID: 38699194 PMCID: PMC11064864 DOI: 10.7717/peerj.17259] [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: 01/08/2024] [Accepted: 03/27/2024] [Indexed: 05/05/2024] Open
Abstract
Iron (Fe) plays a fundamental role in coral symbiosis, supporting photosynthesis, respiration, and many important enzymatic reactions. However, the extent to which corals are limited by Fe and their metabolic responses to inorganic Fe enrichment remains to be understood. We used respirometry, variable chlorophyll fluorescence, and O2 microsensors to investigate the impact of increasing Fe(III) concentrations (20, 50, and 100 nM) on the photosynthetic capacity of two Mediterranean coral species, Cladocora caespitosa and Oculina patagonica. While the bioavailability of inorganic Fe can rapidly decrease, we nevertheless observed significant physiological effects at all Fe concentrations. In C. caespitosa, exposure to 50 nM Fe(III) increased rates of respiration and photosynthesis, while the relative electron transport rate (rETR(II)) decreased at higher Fe(III) exposure (100 nM). In contrast, O. patagonica reduced respiration, photosynthesis rates, and maximum PSII quantum yield (Fv/Fm) across all iron enrichments. Both corals exhibited increased hypoxia (<50 µmol O2 L-1) within their gastric cavity at night when exposed to 50 and 100 nM Fe(III), leading to increased polyp contraction time and reduced O2 exchange with the surrounding water. Our results indicate that C. caespitosa, but not O. patagonica, might be limited in Fe for achieving maximal photosynthetic efficiency. Understanding the multifaceted role of iron in corals' health and their response to environmental change is crucial for effective coral conservation.
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Affiliation(s)
- Walter Dellisanti
- Department of Biology, Marine Biology Section, University of Copenhagen, Helsingør, Denmark
| | - Qingfeng Zhang
- Department of Biology, Marine Biology Section, University of Copenhagen, Helsingør, Denmark
| | - Christine Ferrier-Pagès
- Coral Ecophysiology Laboratory, Center Scientifique de Monaco, Principality of Monaco, Monaco
| | - Michael Kühl
- Department of Biology, Marine Biology Section, University of Copenhagen, Helsingør, Denmark
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2
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Delgadillo-Ordoñez N, Garcias-Bonet N, Raimundo I, García FC, Villela H, Osman EO, Santoro EP, Curdia J, Rosado JGD, Cardoso P, Alsaggaf A, Barno A, Antony CP, Bocanegra C, Berumen ML, Voolstra CR, Benzoni F, Carvalho S, Peixoto RS. Probiotics reshape the coral microbiome in situ without detectable off-target effects in the surrounding environment. Commun Biol 2024; 7:434. [PMID: 38594357 PMCID: PMC11004148 DOI: 10.1038/s42003-024-06135-3] [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: 10/19/2023] [Accepted: 04/02/2024] [Indexed: 04/11/2024] Open
Abstract
Beneficial microorganisms for corals (BMCs), or probiotics, can enhance coral resilience against stressors in laboratory trials. However, the ability of probiotics to restructure the coral microbiome in situ is yet to be determined. As a first step to elucidate this, we inoculated putative probiotic bacteria (pBMCs) on healthy colonies of Pocillopora verrucosa in situ in the Red Sea, three times per week, during 3 months. pBMCs significantly influenced the coral microbiome, while bacteria of the surrounding seawater and sediment remained unchanged. The inoculated genera Halomonas, Pseudoalteromonas, and Bacillus were significantly enriched in probiotic-treated corals. Furthermore, the probiotic treatment also correlated with an increase in other beneficial groups (e.g., Ruegeria and Limosilactobacillus), and a decrease in potential coral pathogens, such as Vibrio. As all corals (treated and non-treated) remained healthy throughout the experiment, we could not track health improvements or protection against stress. Our data indicate that healthy, and therefore stable, coral microbiomes can be restructured in situ, although repeated and continuous inoculations may be required in these cases. Further, our study provides supporting evidence that, at the studied scale, pBMCs have no detectable off-target effects on the surrounding microbiomes of seawater and sediment near inoculated corals.
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Affiliation(s)
- Nathalia Delgadillo-Ordoñez
- Red Sea Research Center, Biological and Environmental Science and Engineering Division, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
- Marine Science and Bioscience Programs, Biological and Environmental Science and Engineering Division, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
| | - Neus Garcias-Bonet
- Red Sea Research Center, Biological and Environmental Science and Engineering Division, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
| | - Inês Raimundo
- Red Sea Research Center, Biological and Environmental Science and Engineering Division, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
- Marine Science and Bioscience Programs, Biological and Environmental Science and Engineering Division, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
| | - Francisca C García
- Red Sea Research Center, Biological and Environmental Science and Engineering Division, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
| | - Helena Villela
- Red Sea Research Center, Biological and Environmental Science and Engineering Division, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
| | - Eslam O Osman
- Red Sea Research Center, Biological and Environmental Science and Engineering Division, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
| | - Erika P Santoro
- Red Sea Research Center, Biological and Environmental Science and Engineering Division, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
| | - Joao Curdia
- Red Sea Research Center, Biological and Environmental Science and Engineering Division, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
| | - Joao G D Rosado
- Red Sea Research Center, Biological and Environmental Science and Engineering Division, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
- Marine Science and Bioscience Programs, Biological and Environmental Science and Engineering Division, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
| | - Pedro Cardoso
- Red Sea Research Center, Biological and Environmental Science and Engineering Division, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
- Marine Science and Bioscience Programs, Biological and Environmental Science and Engineering Division, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
| | - Ahmed Alsaggaf
- Red Sea Research Center, Biological and Environmental Science and Engineering Division, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
- Marine Science and Bioscience Programs, Biological and Environmental Science and Engineering Division, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
| | - Adam Barno
- Red Sea Research Center, Biological and Environmental Science and Engineering Division, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
- Marine Science and Bioscience Programs, Biological and Environmental Science and Engineering Division, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
| | - Chakkiath Paul Antony
- Red Sea Research Center, Biological and Environmental Science and Engineering Division, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
| | - Carolina Bocanegra
- Red Sea Research Center, Biological and Environmental Science and Engineering Division, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
| | - Michael L Berumen
- Red Sea Research Center, Biological and Environmental Science and Engineering Division, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
- Marine Science and Bioscience Programs, Biological and Environmental Science and Engineering Division, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
| | | | - Francesca Benzoni
- Red Sea Research Center, Biological and Environmental Science and Engineering Division, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
- Marine Science and Bioscience Programs, Biological and Environmental Science and Engineering Division, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
| | - Susana Carvalho
- Red Sea Research Center, Biological and Environmental Science and Engineering Division, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
- Marine Science and Bioscience Programs, Biological and Environmental Science and Engineering Division, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
| | - Raquel S Peixoto
- Red Sea Research Center, Biological and Environmental Science and Engineering Division, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia.
- Marine Science and Bioscience Programs, Biological and Environmental Science and Engineering Division, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia.
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3
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Pessarrodona A, Franco-Santos RM, Wright LS, Vanderklift MA, Howard J, Pidgeon E, Wernberg T, Filbee-Dexter K. Carbon sequestration and climate change mitigation using macroalgae: a state of knowledge review. Biol Rev Camb Philos Soc 2023; 98:1945-1971. [PMID: 37437379 DOI: 10.1111/brv.12990] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Revised: 06/05/2023] [Accepted: 06/07/2023] [Indexed: 07/14/2023]
Abstract
The conservation, restoration, and improved management of terrestrial forests significantly contributes to mitigate climate change and its impacts, as well as providing numerous co-benefits. The pressing need to reduce emissions and increase carbon removal from the atmosphere is now also leading to the development of natural climate solutions in the ocean. Interest in the carbon sequestration potential of underwater macroalgal forests is growing rapidly among policy, conservation, and corporate sectors. Yet, our understanding of whether carbon sequestration from macroalgal forests can lead to tangible climate change mitigation remains severely limited, hampering their inclusion in international policy or carbon finance frameworks. Here, we examine the results of over 180 publications to synthesise evidence regarding macroalgal forest carbon sequestration potential. We show that research efforts on macroalgae carbon sequestration are heavily skewed towards particulate organic carbon (POC) pathways (77% of data publications), and that carbon fixation is the most studied flux (55%). Fluxes leading directly to carbon sequestration (e.g. carbon export or burial in marine sediments) remain poorly resolved, likely hindering regional or country-level assessments of carbon sequestration potential, which are only available from 17 of the 150 countries where macroalgal forests occur. To solve this issue, we present a framework to categorize coastlines according to their carbon sequestration potential. Finally, we review the multiple avenues through which this sequestration can translate into climate change mitigation capacity, which largely depends on whether management interventions can increase carbon removal above a natural baseline or avoid further carbon emissions. We find that conservation, restoration and afforestation interventions on macroalgal forests can potentially lead to carbon removal in the order of 10's of Tg C globally. Although this is lower than current estimates of natural sequestration value of all macroalgal habitats (61-268 Tg C year-1 ), it suggests that macroalgal forests could add to the total mitigation potential of coastal blue carbon ecosystems, and offer valuable mitigation opportunities in polar and temperate areas where blue carbon mitigation is currently low. Operationalizing that potential will necessitate the development of models that reliably estimate the proportion of production sequestered, improvements in macroalgae carbon fingerprinting techniques, and a rethinking of carbon accounting methodologies. The ocean provides major opportunities to mitigate and adapt to climate change, and the largest coastal vegetated habitat on Earth should not be ignored simply because it does not fit into existing frameworks.
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Affiliation(s)
- Albert Pessarrodona
- UWA Oceans Institute and School of Biological Sciences, University of Western Australia, Crawley, 6009, Western Australia, Australia
- Conservation International, 2011 Crystal Dr., Suite 600, Arlington, VA, USA
- International Blue Carbon Institute, 42B Boat Quay, Singapore, 049831, Singapore
| | - Rita M Franco-Santos
- CSIRO Environment, Indian Ocean Marine Research Centre, Crawley, 6009, Western Australia, Australia
| | - Luka Seamus Wright
- UWA Oceans Institute and School of Biological Sciences, University of Western Australia, Crawley, 6009, Western Australia, Australia
- CSIRO Environment, Indian Ocean Marine Research Centre, Crawley, 6009, Western Australia, Australia
| | - Mathew A Vanderklift
- CSIRO Environment, Indian Ocean Marine Research Centre, Crawley, 6009, Western Australia, Australia
| | - Jennifer Howard
- Conservation International, 2011 Crystal Dr., Suite 600, Arlington, VA, USA
- International Blue Carbon Institute, 42B Boat Quay, Singapore, 049831, Singapore
| | - Emily Pidgeon
- Conservation International, 2011 Crystal Dr., Suite 600, Arlington, VA, USA
- International Blue Carbon Institute, 42B Boat Quay, Singapore, 049831, Singapore
| | - Thomas Wernberg
- UWA Oceans Institute and School of Biological Sciences, University of Western Australia, Crawley, 6009, Western Australia, Australia
- Institute of Marine Research, Nye Flødevigveien 20, His, 4817, Norway
| | - Karen Filbee-Dexter
- UWA Oceans Institute and School of Biological Sciences, University of Western Australia, Crawley, 6009, Western Australia, Australia
- Institute of Marine Research, Nye Flødevigveien 20, His, 4817, Norway
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4
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Rodriguez-Ruano V, Toth LT, Enochs IC, Randall CJ, Aronson RB. Upwelling, climate change, and the shifting geography of coral reef development. Sci Rep 2023; 13:1770. [PMID: 36750639 PMCID: PMC9905564 DOI: 10.1038/s41598-023-28489-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Accepted: 01/19/2023] [Indexed: 02/09/2023] Open
Abstract
The eastern tropical Pacific is oceanographically unfavorable for coral-reef development. Nevertheless, reefs have persisted there for the last 7000 years. Rates of vertical accretion during the Holocene have been similar in the strong-upwelling Gulf of Panamá (GoP) and the adjacent, weak-upwelling Gulf of Chiriquí (GoC); however, seasonal upwelling in the GoP exacerbated a climate-driven hiatus in reef development in the late Holocene. The situation is now reversed and seasonal upwelling in the GoP currently buffers thermal stress, creating a refuge for coral growth. We developed carbonate budget models to project the capacity of reefs in both gulfs to keep up with future sea-level rise. On average, the GoP had significantly higher net carbonate production rates than the GoC. With an estimated contemporary reef-accretion potential (RAP) of 5.5 mm year-1, reefs in the GoP are projected to be able to keep up with sea-level rise if CO2 emissions are reduced, but not under current emissions trajectories. With an estimated RAP of just 0.3 mm year-1, reefs in the GoC are likely already unable to keep up with contemporary sea-level rise in Panamá (1.4 mm year-1). Whereas the GoP has the potential to support functional reefs in the near-term, our study indicates that their long-term persistence will depend on reduction of greenhouse gases.
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Affiliation(s)
- Victor Rodriguez-Ruano
- Department of Ocean Engineering and Marine Sciences, Florida Institute of Technology, 150 West University Boulevard, Melbourne, FL, 32901, USA.
| | - Lauren T Toth
- U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center, 600 4th St. South, St. Petersburg, FL, 33701, USA
| | - Ian C Enochs
- 3NOAA, Atlantic Oceanographic and Meteorological Laboratory, Ocean Chemistry and Ecosystem Division, 4301 Rickenbacker Cswy., Miami, FL, 33149, USA
| | - Carly J Randall
- Australian Institute of Marine Science, PMB No. 3, Townsville, QLD, 4810, Australia
| | - Richard B Aronson
- Department of Ocean Engineering and Marine Sciences, Florida Institute of Technology, 150 West University Boulevard, Melbourne, FL, 32901, USA
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5
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Mueller B, Brocke HJ, Rohwer FL, Dittmar T, Huisman J, Vermeij MJA, de Goeij JM. Nocturnal dissolved organic matter release by turf algae and its role in the microbialization of reefs. Funct Ecol 2022; 36:2104-2118. [PMID: 36247100 PMCID: PMC9543674 DOI: 10.1111/1365-2435.14101] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2021] [Accepted: 04/29/2022] [Indexed: 11/27/2022]
Abstract
The increased release of dissolved organic matter (DOM) by algae has been associated with the fast but inefficient growth of opportunistic microbial pathogens and the ongoing degradation of coral reefs. Turf algae (consortia of microalgae and macroalgae commonly including cyanobacteria) dominate benthic communities on many reefs worldwide. Opposite to other reef algae that predominantly release DOM during the day, turf algae containing cyanobacteria may additionally release large amounts of DOM at night. However, this night-DOM release and its potential contribution to the microbialization of reefs remains to be investigated.We first tested the occurrence of hypoxic conditions at the turf algae-water interface, as a lack of oxygen will facilitate the production and release of fermentation intermediates as night-time DOM. Second, the dissolved organic carbon (DOC) release by turf algae was quantified during day time and nighttime, and the quality of day and night exudates as food for bacterioplankton was tested. Finally, DOC release rates of turf algae were combined with estimates of DOC release based on benthic community composition in 1973 and 2013 to explore how changes in benthic community composition affected the contribution of night-DOC to the reef-wide DOC production.A rapid shift from supersaturated to hypoxic conditions at the turf algae-water interface occurred immediately after the onset of darkness, resulting in night-DOC release rates similar to those during daytime. Bioassays revealed major differences in the quality between day and night exudates: Night-DOC was utilized by bacterioplankton two times faster than day-DOC, but yielded a four times lower growth efficiency. Changes in benthic community composition were estimated to have resulted in a doubling of DOC release since 1973, due to an increasing abundance of benthic cyanobacterial mats (BCMs), with night-DOC release by BCMs and turf algae accounting for >50% of the total release over a diurnal cycle.Night-DOC released by BCMs and turf algae is likely an important driver in the microbialization of reefs by stimulating microbial respiration at the expense of energy and nutrient transfer to higher trophic levels via the microbial loop, thereby threatening the productivity and biodiversity of these unique ecosystems. Read the free Plain Language Summary for this article on the Journal blog.
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Affiliation(s)
- Benjamin Mueller
- Department for Freshwater and Marine EcologyUniversity of AmsterdamAmsterdamThe Netherlands
- CARMABI FoundationWillemstadCuraçao
- Department of Oceanography and Sea Grant College ProgramCenter for Microbial Oceanography: Research and Education, University of Hawai'i at MānoaHonoluluHawaiiUSA
| | - Hannah J. Brocke
- Max‐Plank Institute for Marine Microbiology (MPI Bremen)BremenGermany
| | - Forest L. Rohwer
- Department of BiologySan Diego State UniversitySan DiegoCaliforniaUSA
| | - Thorsten Dittmar
- Institute for Chemistry and Biology of the Marine EnvironmentUniversity of OldenburgOldenburgGermany
- Helmholtz Institute for Functional Marine Biodiversity (HIFMB)University of OldenburgOldenburgGermany
| | - Jef Huisman
- Department for Freshwater and Marine EcologyUniversity of AmsterdamAmsterdamThe Netherlands
| | - Mark J. A. Vermeij
- Department for Freshwater and Marine EcologyUniversity of AmsterdamAmsterdamThe Netherlands
- CARMABI FoundationWillemstadCuraçao
| | - Jasper M. de Goeij
- Department for Freshwater and Marine EcologyUniversity of AmsterdamAmsterdamThe Netherlands
- CARMABI FoundationWillemstadCuraçao
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6
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Rädecker N, Pogoreutz C, Gegner HM, Cárdenas A, Perna G, Geißler L, Roth F, Bougoure J, Guagliardo P, Struck U, Wild C, Pernice M, Raina JB, Meibom A, Voolstra CR. Heat stress reduces the contribution of diazotrophs to coral holobiont nitrogen cycling. THE ISME JOURNAL 2021; 16:1110-1118. [PMID: 34857934 PMCID: PMC8941099 DOI: 10.1038/s41396-021-01158-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Revised: 11/11/2021] [Accepted: 11/16/2021] [Indexed: 12/22/2022]
Abstract
Efficient nutrient cycling in the coral-algal symbiosis requires constant but limited nitrogen availability. Coral-associated diazotrophs, i.e., prokaryotes capable of fixing dinitrogen, may thus support productivity in a stable coral-algal symbiosis but could contribute to its breakdown when overstimulated. However, the effects of environmental conditions on diazotroph communities and their interaction with other members of the coral holobiont remain poorly understood. Here we assessed the effects of heat stress on diazotroph diversity and their contribution to holobiont nutrient cycling in the reef-building coral Stylophora pistillata from the central Red Sea. In a stable symbiotic state, we found that nitrogen fixation by coral-associated diazotrophs constitutes a source of nitrogen to the algal symbionts. Heat stress caused an increase in nitrogen fixation concomitant with a change in diazotroph communities. Yet, this additional fixed nitrogen was not assimilated by the coral tissue or the algal symbionts. We conclude that although diazotrophs may support coral holobiont functioning under low nitrogen availability, altered nutrient cycling during heat stress abates the dependence of the coral host and its algal symbionts on diazotroph-derived nitrogen. Consequently, the role of nitrogen fixation in the coral holobiont is strongly dependent on its nutritional status and varies dynamically with environmental conditions.
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Affiliation(s)
- Nils Rädecker
- Red Sea Research Center, Division of Biological and Environmental Science and Engineering, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia. .,Department of Biology, University of Konstanz, Konstanz, Germany. .,Laboratory for Biological Geochemistry, School of Architecture, Civil and Environmental Engineering, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.
| | - Claudia Pogoreutz
- Red Sea Research Center, Division of Biological and Environmental Science and Engineering, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia.,Department of Biology, University of Konstanz, Konstanz, Germany
| | - Hagen M Gegner
- Red Sea Research Center, Division of Biological and Environmental Science and Engineering, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia.,Metabolomics Core Technology Platform, Centre for Organismal Studies, University of Heidelberg, Heidelberg, Germany
| | - Anny Cárdenas
- Red Sea Research Center, Division of Biological and Environmental Science and Engineering, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia.,Department of Biology, University of Konstanz, Konstanz, Germany
| | - Gabriela Perna
- Red Sea Research Center, Division of Biological and Environmental Science and Engineering, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia.,Department of Biology, University of Konstanz, Konstanz, Germany
| | - Laura Geißler
- Department of Biology, University of Konstanz, Konstanz, Germany
| | - Florian Roth
- Red Sea Research Center, Division of Biological and Environmental Science and Engineering, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia.,Baltic Sea Centre, Stockholm University, Stockholm, Sweden.,Faculty of Biological and Environmental Sciences, Tvärminne Zoological Station, University of Helsinki, Helsinki, Finland
| | - Jeremy Bougoure
- Centre for Microscopy, Characterisation and Analysis, University of Western Australia, Perth, WA, Australia
| | - Paul Guagliardo
- Centre for Microscopy, Characterisation and Analysis, University of Western Australia, Perth, WA, Australia
| | - Ulrich Struck
- Museum für Naturkunde, Leibniz Institute for Evolution and Biodiversity Science, Berlin, Germany.,Department of Earth Sciences, Freie Universität Berlin, Berlin, Germany
| | - Christian Wild
- Faculty of Biology and Chemistry, Marine Ecology Department, University of Bremen, Bremen, Germany
| | - Mathieu Pernice
- Climate Change Cluster, University of Technology Sydney, Sydney, NSW, Australia
| | - Jean-Baptiste Raina
- Climate Change Cluster, University of Technology Sydney, Sydney, NSW, Australia
| | - Anders Meibom
- Laboratory for Biological Geochemistry, School of Architecture, Civil and Environmental Engineering, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.,Center for Advanced Surface Analysis, Institute of Earth Sciences, Université de Lausanne, Lausanne, Switzerland
| | - Christian R Voolstra
- Red Sea Research Center, Division of Biological and Environmental Science and Engineering, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia.,Department of Biology, University of Konstanz, Konstanz, Germany
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7
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Dellisanti W, Chung JTH, Chow CFY, Wu J, Wells ML, Chan LL. Experimental Techniques to Assess Coral Physiology in situ Under Global and Local Stressors: Current Approaches and Novel Insights. Front Physiol 2021; 12:656562. [PMID: 34163371 PMCID: PMC8215126 DOI: 10.3389/fphys.2021.656562] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Accepted: 04/09/2021] [Indexed: 11/19/2022] Open
Abstract
Coral reefs are declining worldwide due to global changes in the marine environment. The increasing frequency of massive bleaching events in the tropics is highlighting the need to better understand the stages of coral physiological responses to extreme conditions. Moreover, like many other coastal regions, coral reef ecosystems are facing additional localized anthropogenic stressors such as nutrient loading, increased turbidity, and coastal development. Different strategies have been developed to measure the health status of a damaged reef, ranging from the resolution of individual polyps to the entire coral community, but techniques for measuring coral physiology in situ are not yet widely implemented. For instance, while there are many studies of the coral holobiont response in single or limited-number multiple stressor experiments, they provide only partial insights into metabolic performance under more complex and temporally and spatially variable natural conditions. Here, we discuss the current status of coral reefs and their global and local stressors in the context of experimental techniques that measure core processes in coral metabolism (respiration, photosynthesis, and biocalcification) in situ, and their role in indicating the health status of colonies and communities. We highlight the need to improve the capability of in situ studies in order to better understand the resilience and stress response of corals under multiple global and local scale stressors.
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Affiliation(s)
- Walter Dellisanti
- State Key Laboratory of Marine Pollution, City University of Hong Kong, Kowloon, China.,Department of Biomedical Sciences, City University of Hong Kong, Kowloon, China
| | - Jeffery T H Chung
- State Key Laboratory of Marine Pollution, City University of Hong Kong, Kowloon, China
| | - Cher F Y Chow
- State Key Laboratory of Marine Pollution, City University of Hong Kong, Kowloon, China.,Centre for Biological Diversity, Scottish Oceans Institute, School of Biology, University of St Andrews, St Andrews, United Kingdom
| | - Jiajun Wu
- State Key Laboratory of Marine Pollution, City University of Hong Kong, Kowloon, China
| | - Mark L Wells
- School of Marine Sciences, University of Maine, Orono, ME, United States.,State Key Laboratory of Satellite Ocean Environment Dynamics, Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou, China
| | - Leo L Chan
- State Key Laboratory of Marine Pollution, City University of Hong Kong, Kowloon, China.,Department of Biomedical Sciences, City University of Hong Kong, Kowloon, China.,Hong Kong Branch of Southern Marine Science and Engineering Guangdong Laboratory, Guangzhou, China
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8
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El-Khaled YC, Roth F, Rädecker N, Tilstra A, Karcher DB, Kürten B, Jones BH, Voolstra CR, Wild C. Nitrogen fixation and denitrification activity differ between coral- and algae-dominated Red Sea reefs. Sci Rep 2021; 11:11820. [PMID: 34083565 PMCID: PMC8175748 DOI: 10.1038/s41598-021-90204-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Accepted: 05/07/2021] [Indexed: 11/18/2022] Open
Abstract
Coral reefs experience phase shifts from coral- to algae-dominated benthic communities, which could affect the interplay between processes introducing and removing bioavailable nitrogen. However, the magnitude of such processes, i.e., dinitrogen (N2) fixation and denitrification levels, and their responses to phase shifts remain unknown in coral reefs. We assessed both processes for the dominant species of six benthic categories (hard corals, soft corals, turf algae, coral rubble, biogenic rock, and reef sands) accounting for > 98% of the benthic cover of a central Red Sea coral reef. Rates were extrapolated to the relative benthic cover of the studied organisms in co-occurring coral- and algae-dominated areas of the same reef. In general, benthic categories with high N2 fixation exhibited low denitrification activity. Extrapolated to the respective reef area, turf algae and coral rubble accounted for > 90% of overall N2 fixation, whereas corals contributed to more than half of reef denitrification. Total N2 fixation was twice as high in algae- compared to coral-dominated areas, whereas denitrification levels were similar. We conclude that algae-dominated reefs promote new nitrogen input through enhanced N2 fixation and comparatively low denitrification. The subsequent increased nitrogen availability could support net productivity, resulting in a positive feedback loop that increases the competitive advantage of algae over corals in reefs that experienced a phase shift.
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Affiliation(s)
- Yusuf C El-Khaled
- Marine Ecology Department, Faculty of Biology and Chemistry, University of Bremen, 28359, Bremen, Germany.
| | - Florian Roth
- Red Sea Research Center, King Abdullah University of Science and Technology (KAUST), Thuwal, 23995, Saudi Arabia
- Baltic Sea Centre, Stockholm University, 10691, Stockholm, Sweden
- Faculty of Biological and Environmental Sciences, Tvärminne Zoological Station, University of Helsinki, 00014, Helsinki, Finland
| | - Nils Rädecker
- Red Sea Research Center, King Abdullah University of Science and Technology (KAUST), Thuwal, 23995, Saudi Arabia
- Department of Biology, University of Konstanz, 78457, Konstanz, Germany
- Laboratory for Biological Geochemistry, School of Architecture, Civil and Environmental Engineering, École Polytechnique Fédérale de Lausanne (EPFL), 1015, Lausanne, Switzerland
| | - Arjen Tilstra
- Marine Ecology Department, Faculty of Biology and Chemistry, University of Bremen, 28359, Bremen, Germany
| | - Denis B Karcher
- Marine Ecology Department, Faculty of Biology and Chemistry, University of Bremen, 28359, Bremen, Germany
- Australian National Centre for the Public Awareness of Science, Australian National University, ACT, Canberra, 2601, Australia
| | - Benjamin Kürten
- Red Sea Research Center, King Abdullah University of Science and Technology (KAUST), Thuwal, 23995, Saudi Arabia
- Project Management Jülich, Jülich Research Centre GmbH, 18069, Rostock, Germany
| | - Burton H Jones
- Red Sea Research Center, King Abdullah University of Science and Technology (KAUST), Thuwal, 23995, Saudi Arabia
| | - Christian R Voolstra
- Red Sea Research Center, King Abdullah University of Science and Technology (KAUST), Thuwal, 23995, Saudi Arabia
- Department of Biology, University of Konstanz, 78457, Konstanz, Germany
| | - Christian Wild
- Marine Ecology Department, Faculty of Biology and Chemistry, University of Bremen, 28359, Bremen, Germany
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9
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Tilstra A, Roth F, El-Khaled YC, Pogoreutz C, Rädecker N, Voolstra CR, Wild C. Relative abundance of nitrogen cycling microbes in coral holobionts reflects environmental nitrate availability. ROYAL SOCIETY OPEN SCIENCE 2021; 8:201835. [PMID: 34109033 PMCID: PMC8170195 DOI: 10.1098/rsos.201835] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Accepted: 05/14/2021] [Indexed: 06/12/2023]
Abstract
Recent research suggests that nitrogen (N) cycling microbes are important for coral holobiont functioning. In particular, coral holobionts may acquire bioavailable N via prokaryotic dinitrogen (N2) fixation or remove excess N via denitrification activity. However, our understanding of environmental drivers on these processes in hospite remains limited. Employing the strong seasonality of the central Red Sea, this study assessed the effects of environmental parameters on the proportional abundances of N cycling microbes associated with the hard corals Acropora hemprichii and Stylophora pistillata. Specifically, we quantified changes in the relative ratio between nirS and nifH gene copy numbers, as a proxy for seasonal shifts in denitrification and N2 fixation potential in corals, respectively. In addition, we assessed coral tissue-associated Symbiodiniaceae cell densities and monitored environmental parameters to provide a holobiont and environmental context, respectively. While ratios of nirS to nifH gene copy numbers varied between seasons, they revealed similar seasonal patterns in both coral species, with ratios closely following patterns in environmental nitrate availability. Symbiodiniaceae cell densities aligned with environmental nitrate availability, suggesting that the seasonal shifts in nirS to nifH gene abundance ratios were probably driven by nitrate availability in the coral holobiont. Thereby, our results suggest that N cycling in coral holobionts probably adjusts to environmental conditions by increasing and/or decreasing denitrification and N2 fixation potential according to environmental nitrate availability. Microbial N cycling may, thus, extenuate the effects of changes in environmental nitrate availability on coral holobionts to support the maintenance of the coral-Symbiodiniaceae symbiosis.
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Affiliation(s)
- Arjen Tilstra
- Marine Ecology Department, Faculty of Biology and Chemistry, University of Bremen, Bremen, Germany
| | - Florian Roth
- Red Sea Research Center, King Abdullah University of Science and Technology, Thuwal, Kingdom of Saudi Arabia
- Baltic Sea Centre, Stockholm University, Stockholm, Sweden
- Tvärminne Zoological Station, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland
| | - Yusuf C. El-Khaled
- Marine Ecology Department, Faculty of Biology and Chemistry, University of Bremen, Bremen, Germany
| | - Claudia Pogoreutz
- Red Sea Research Center, King Abdullah University of Science and Technology, Thuwal, Kingdom of Saudi Arabia
- Department of Biology, University of Konstanz, Konstanz, Germany
| | - Nils Rädecker
- Red Sea Research Center, King Abdullah University of Science and Technology, Thuwal, Kingdom of Saudi Arabia
- Department of Biology, University of Konstanz, Konstanz, Germany
- Laboratory for Biological Geochemistry, School of Architecture, Civil and Environmental Engineering, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Christian R. Voolstra
- Red Sea Research Center, King Abdullah University of Science and Technology, Thuwal, Kingdom of Saudi Arabia
- Department of Biology, University of Konstanz, Konstanz, Germany
| | - Christian Wild
- Marine Ecology Department, Faculty of Biology and Chemistry, University of Bremen, Bremen, Germany
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10
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Roth F, RAdecker N, Carvalho S, Duarte CM, Saderne V, Anton A, Silva L, Calleja ML, MorÁn XAG, Voolstra CR, Kürten B, Jones BH, Wild C. High summer temperatures amplify functional differences between coral- and algae-dominated reef communities. Ecology 2020; 102:e03226. [PMID: 33067806 PMCID: PMC7900985 DOI: 10.1002/ecy.3226] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Revised: 07/06/2020] [Accepted: 08/24/2020] [Indexed: 12/30/2022]
Abstract
Shifts from coral to algal dominance are expected to increase in tropical coral reefs as a result of anthropogenic disturbances. The consequences for key ecosystem functions such as primary productivity, calcification, and nutrient recycling are poorly understood, particularly under changing environmental conditions. We used a novel in situ incubation approach to compare functions of coral‐ and algae‐dominated communities in the central Red Sea bimonthly over an entire year. In situ gross and net community primary productivity, calcification, dissolved organic carbon fluxes, dissolved inorganic nitrogen fluxes, and their respective activation energies were quantified to describe the effects of seasonal changes. Overall, coral‐dominated communities exhibited 30% lower net productivity and 10 times higher calcification than algae‐dominated communities. Estimated activation energies indicated a higher thermal sensitivity of coral‐dominated communities. In these communities, net productivity and calcification were negatively correlated with temperature (>40% and >65% reduction, respectively, with +5°C increase from winter to summer), whereas carbon losses via respiration and dissolved organic carbon release more than doubled at higher temperatures. In contrast, algae‐dominated communities doubled net productivity in summer, while calcification and dissolved organic carbon fluxes were unaffected. These results suggest pronounced changes in community functioning associated with coral‐algal phase shifts. Algae‐dominated communities may outcompete coral‐dominated communities because of their higher productivity and carbon retention to support fast biomass accumulation while compromising the formation of important reef framework structures. Higher temperatures likely amplify these functional differences, indicating a high vulnerability of ecosystem functions of coral‐dominated communities to temperatures even below coral bleaching thresholds. Our results suggest that ocean warming may not only cause but also amplify coral–algal phase shifts in coral reefs.
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Affiliation(s)
- Florian Roth
- Red Sea Research Center, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955, Saudi Arabia.,Baltic Sea Centre, Stockholm University, Stockholm, 10691, Sweden.,Faculty of Biological and Environmental Sciences, Tvärminne Zoological Station, University of Helsinki, Helsinki, 00014, Finland
| | - Nils RAdecker
- Red Sea Research Center, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955, Saudi Arabia.,Department of Biology, University of Konstanz, Konstanz, 78457, Germany.,Laboratory for Biological Geochemistry, School of Architecture, Civil and Environmental Engineering, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, 1015, Switzerland
| | - Susana Carvalho
- Red Sea Research Center, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955, Saudi Arabia
| | - Carlos M Duarte
- Red Sea Research Center, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955, Saudi Arabia.,Computational Biology Research Center, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955, Saudi Arabia
| | - Vincent Saderne
- Red Sea Research Center, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955, Saudi Arabia
| | - Andrea Anton
- Red Sea Research Center, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955, Saudi Arabia.,Computational Biology Research Center, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955, Saudi Arabia
| | - Luis Silva
- Red Sea Research Center, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955, Saudi Arabia
| | - Maria Ll Calleja
- Red Sea Research Center, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955, Saudi Arabia.,Department of Climate Geochemistry, Max Planck Institute for Chemistry (MPIC), Mainz, 55128, Germany
| | - XosÉ Anxelu G MorÁn
- Red Sea Research Center, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955, Saudi Arabia
| | - Christian R Voolstra
- Red Sea Research Center, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955, Saudi Arabia.,Department of Biology, University of Konstanz, Konstanz, 78457, Germany
| | - Benjamin Kürten
- Red Sea Research Center, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955, Saudi Arabia.,Project Management Jülich, Jülich Research Centre GmbH, Rostock, 52425, Germany
| | - Burton H Jones
- Red Sea Research Center, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955, Saudi Arabia
| | - Christian Wild
- Marine Ecology, Faculty of Biology and Chemistry, University of Bremen, Bremen, 28359, Germany
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