Coral Reef Ecology Research Articles

Distinct coral environments shape the dynamic of planktonic Vibrio spp.

BackgroundCoral reefs are one of the most biodiverse and productive ecosystems, providing habitat for a vast of species. Reef-building scleractinian corals with a symbiotic microbiome, including bacteria, archaea, viruses and eukaryotic microbes, are referred to coral holobionts. Among them, coral diseases, mainly caused by Vibrio spp., have significantly contributed to the loss of coral cover and diversity. Habitat filtering across the globe has led to a variety structure of marine bacterial communities. Coral species, quantity and characteristics are significant differences between the Xisha Islands and Daya Bay (Guangdong Province). Thus, the Vibrio communities may be distinct between coral rich and poor areas.ResultsThrough comparison of Vibrio dynamics between coral-rich (Xisha Islands) and coral-poor (Daya Bay) locations, we uncovered differences in Vibrio abundance, diversity, community composition and assembly mechanisms associated with corals. The higher abundance of Vibrio in coral rich areas may indicate a strong interaction between vibrios and corals. V. campbellii, Paraphotobacterium marinum and V. caribbeanicus were widely distributed in both coral rich and poor areas, likely indicating weak species specificity in the coral-stimulated growth of Vibrio. Random-forest prediction revealed Vibrio species and Photobacterium species as potential microbial indicators in the coral rich and coral poor areas, respectively. Ecological drift rather than selection governed the Vibrio community assembly in the Xisha Islands. Comparatively, homogenizing selection was more important for the Daya Bay community, which may reflect a role of habitat filtration.ConclusionThis study revealed the different distribution pattern and assembly mechanism of Vibrio spp. between coral rich and poor areas, providing the background data for the research of Vibrio community in coral reef areas and may help the protection of coral reef at the biological level. The main reasons for the difference were different number and species of corals, environmental (e.g., temperature) and spatial factors. It reflected the strong interaction between Vibrio and corals, and provided a new perspective for the investigation of Vibrio in coral reef ecosystem.

Coral restoration in the Philippines: Interactions with key coastal sectors

Much work on coral restoration to date has focused on experimenting with diverse technical approaches and techniques. As the implementation of coral restoration globally increases, it is increasingly recognized that there is a need to better understand how to govern this emerging technology effectively, which requires assessing the social, economic and political contexts in which reefs are restored. This study examined the interactions (both current and potential) between the dominant economic sectors in coastal Philippines and coral restoration. Informed by ongoing coral restoration efforts in Pangasinan province, the paper draws on social data collection of the major coastal economic sectors in the province. Large-scale aquaculture of milkfish generates significant challenges to existing and new efforts at coral restoration as the industry is poorly regulated and environmentally damaging. Destructive fishing methods persist due to weak enforcement capacities and likewise pose challenges to coral restoration. Tourism, as an increasingly important economic activity in the region, potentially provides synergies between coral restoration and local economies. This study highlights that interactions between these business sectors and organisations working to protect coral reefs will go a long way to shaping the eventual governability and sustainability of coral restoration projects. Future reef restoration initiatives need to understand the interactions and dynamics of these sectors in specific contexts, and to identify strategies to manage them for the restoration interventions to work effectively and ultimately generate sustained benefits.

Policy and Implementation of Coral Reef Protection in the Face of the Threat of Foreign Ships

Protection of coral reefs in Indonesia from damage caused by foreign ships is an important issue in preserving the maritime environment. is based on Law Number 27 of 2007 and the 1982 Law of the Sea Convention (UNCLOS 1982) which provides the legal basis for protecting marine ecosystems. Steps to increase coral reef protection include setting up zones that limit ship activities, implementing sanctions and strict fines, development of an effective monitoring system, increasing public awareness about the impacts of foreign vessels, and educating fishermen about sustainable fishing practices. International cooperation is an important aspect in dealing with this problem, with collaboration between Indonesia, neighboring countries, and organizations international. This joint effort aims to preserve coral reefs which are a valuable natural resource for Indonesia. The importance of preserving coral reefs as a crucial ecosystem and valuable natural resource for Indonesia must not be ignored. Protection of coral reefs must be a priority in efforts to preserve the environment in Indonesia for a sustainable future.

Strong hydrodynamic drivers of coral reef fish biodiversity on submerged pinnacle coral reefs

AbstractHydrodynamic processes are important in all marine environments and on coral reefs drive patterns of habitat zonation, community structure, and biodiversity. Abrupt geomorphological features like pinnacles and seamounts often possess distinct localized currents and these habitats are also often characterized by high abundance and biomass of fishes. However, differences in fish community structure between pinnacles and emergent reefs, and their key drivers are poorly understood. In this study, we compared fish communities among emergent fringing and offshore coral reefs, and submerged pinnacle reefs in Papua New Guinea. Submerged pinnacles possessed higher fish biomass, abundance, and species richness than both fringing and offshore emergent reefs. We collected in‐situ current speed and temperature data over a full year at each reef and used random forest analysis to investigate the relative influence of hydrodynamics compared to other well‐established drivers of reef fish biodiversity, including habitat and biogeographic factors. Environmental variables explained 70%, 52%, and 5% of variability in models for species richness, abundance and biomass respectively. In all models, average current speed, current speed variability, and reef area were consistently among the most influential variables. Models examining relationships between fish biodiversity metrics and current speed did not yield conclusive results but did highlight the association of distinct hydrodynamic regimes on pinnacles with high fish richness, abundance, and biomass. Our study highlights the strong influence of reef‐scale hydrodynamics on fish biodiversity and demonstrates the ecological value of small, submerged coral reefs, which are globally numerous yet remain understudied in coral reef ecology.

Winter and Summer Variations in the Physiological Parameters of Two Scleractinian Corals in Sanya Bay

Coral reefs in Sanya Bay have been degrading in recent decades under climate change and human activities. To identify physiological changes of scleractinian corals and corresponding influencing factors, aquatic environmental factors and physiological parameters of Pocillopora damicornis, Porites pukoensis and their symbiotic zooxanthellae were examined in four Sanya Bay coral reef areas in December 2020 (winter) and July 2021 (summer). The density and chlorophyll a+c2 content of the symbiotic zooxanthellae were significantly high in winter and low in summer. Superoxide dismutase and caspase3 activities of corals and zooxanthellae were high in summer and low in winter, whereas catalase activity showed the opposite pattern. The variations were consistent for both coral symbionts. Water temperature and salinity were the main factors affecting the physiological variations of corals. Compared with winter, the high temperature/low salinity aquatic environment in summer reduced the density and chlorophyll a+c2 content of zooxanthellae, resulting in high superoxide dismutase and caspase3 activities in the corals and zooxanthellae. In addition, turbidity was an important factor affecting the physiological characteristics of coral–zooxanthellae symbionts among the four coral reef areas. Our results have important implications for understanding the changes in coral reef communities in Sanya Bay and coral reef protection.

The role and risks of selective adaptation in extreme coral habitats

The alarming rate of climate change demands new management strategies to protect coral reefs. Environments such as mangrove lagoons, characterized by extreme variations in multiple abiotic factors, are viewed as potential sources of stress-tolerant corals for strategies such as assisted evolution and coral propagation. However, biological trade-offs for adaptation to such extremes are poorly known. Here, we investigate the reef-building coral Porites lutea thriving in both mangrove and reef sites and show that stress-tolerance comes with compromises in genetic and energetic mechanisms and skeletal characteristics. We observe reduced genetic diversity and gene expression variability in mangrove corals, a disadvantage under future harsher selective pressure. We find reduced density, thickness and higher porosity in coral skeletons from mangroves, symptoms of metabolic energy redirection to stress response functions. These findings demonstrate the need for caution when utilizing stress-tolerant corals in human interventions, as current survival in extremes may compromise future competitive fitness.

Trophic ecology of Angolan cold-water coral reefs (SE Atlantic) based on stable isotope analyses

Cold-water coral (CWC) reefs of the Angolan margin (SE Atlantic) are dominated by Desmophyllum pertusum and support a diverse community of associated fauna, despite hypoxic conditions. In this study, we use carbon and nitrogen stable isotope analyses (δ13C and δ15N) to decipher the trophic network of this relatively unknown CWC province. Although fresh phytodetritus is available to the reef, δ15N signatures indicate that CWCs (12.90 ± 1.00 ‰) sit two trophic levels above Suspended Particulate Organic Matter (SPOM) (4.23 ± 1.64 ‰) suggesting that CWCs are highly reliant on an intermediate food source, which may be zooplankton. Echinoderms and the polychaete Eunice norvegica occupy the same trophic guild, with high δ13C signatures (-14.00 ± 1.08 ‰) pointing to a predatory feeding behavior on CWCs and sponges, although detrital feeding on 13C enriched particles might also be important for this group. Sponges presented the highest δ15N values (20.20 ± 1.87 ‰), which could be due to the role of the sponge holobiont and bacterial food in driving intense nitrogen cycling processes in sponges’ tissue, helping to cope with the hypoxic conditions of the reef. Our study provides first insights to understand trophic interactions of CWC reefs under low-oxygen conditions.

Towards reef restoration in Zihuatanejo, Guerrero, México: lessons learned

Introduction: Coral reef structures in Zihuatanejo, Guerrero are well-preserved. The coverage of living corals, near 60 % at several locations, makes them comparable to other coral reefs in the states of Oaxaca, Jalisco, and Nayarit and with high potential to promote their conservation.
 Objective: To present the outcome of 12 years of research in coral communities from Zihuatanejo, Guerrero, as a justifying argument for the current conservation efforts in the area.
 Methods: We developed a baseline on the conservation status of the reef structures, bioerosion processes and the source of major natural and anthropogenic impacts. We assessed the genetic diversity of the coral zooxanthellae symbionts, the outcome of a technique of coral transplantation to recover the coverage of living corals and the local ecological knowledge to involve local inhabitants to promote conservation.
 Results: At least five coral reefs remain exposed to a medium-low level of impact by bioerosion and anthropization. Coral transplantation experiments made in the area showed records of transplant survival nearing 90 %. Although the warming of the sea surface temperature that occurred during the El Niño of 2015-2016 caused coral bleaching and mortality in several coral populations in this area, there were no affectations attributed to this phenomenon in other locations. This response was not related to the level of exposure to anthropogenic impacts, and the presence of thermal resistant zooxanthellae was assessed using molecular tools, confirming the existence of zooxanthellae of the genus Durusdinium. The analysis of local ecological knowledge of the inhabitants of Zihuatanejo showed that they keep elaborate knowledge on the ecology of coral reefs. This is complemented with scientific knowledge that will encourage community participation in conservation strategies.
 Conclusions: A long-term multidisciplinary strategy is required for coral reef conservation that encompasses: 1) assessing the role of the overall holobiont in the thermal resistance of corals from this area and 2) establishing restoration strategies of coral reefs that include the local knowledge about marine ecology, for the establishment of coral reef protection and management schemes put in place by local inhabitants.

Climate Change and the Change of Trophic Level Interaction in Coral Reefs Based on South China Sea in China

In recent years, coral reefs have been seriously affected by human and natural factors, some of influences are even irreversible. Among them, the impacts of climate change have gradually deepened and attracted people's attention. Other papers which tell about the familiar topic failed to focus on discussing specific questions in certain area of coral reefs. The paper mainly analyzes the interspecific relationship change when facing the climate change of coral reef ecology in the South China Sea. Content of this paper first discusses the severe condition of climate change, like the instability of global climate system. Also, the situation about South China Sea and the effects of climate change are discussed and analyzed. Then, the interspecific relationships of predation, competition, parasitism, and mutualism were discussed. Further, discussed the increase of benthic algae and symbiotic organism reactions. The response from higher trophic level to low level and some researches are determined, too. On this basis, consider the interspecific relationships in the same trophic level. In the future, higher trophic level changes should be determined. Also, people should focus on the change after coral reefs recovering from albinism, about whether their population would change even extinct with the effect of climate change on coral reefs and reefs make a response to it through trophic level relationship change. This paper can provide some corresponding research ideas for more future researches.

Coral Bleaching on the Great Barrier Reef and Causes

With the increasing problem of global warming, the Earth's environment has been seriously damaged in recent decades, especially the Marine environment. Covering 71 percent of the Earth, the oceans are an important part of the planet, but such a beautiful and rich resource is now in decline. This paper mainly expounds the embodiment of environmental problems in coral reefs (take the Great Barrier Reef as an example). Large numbers of coral reefs are bleaching and dying because of climate change. Nowadays, the problem of severe Marine environment is getting worse and worse, which has aroused people's great attention in the world. The main causes of coral bleaching are rising temperatures, eating crown-of-thorns starfish and acidification. Finally, this paper expounds the damage to the ecological environment and the disasters faced by human beings if coral reefs are lost. In the future, we should do our best to protect coral reefs and prohibit vandalism, pollution and overfishing. And can artificially cultivate, transplant coral reefs, remove coral pests and so on. This article aims to point out the causes of coral bleaching, so that more people can realize the crisis we are facing, and call on people to take small steps to protect our only planet.

Correction to: The Cayman Crown: newly protected coral reefs at the edge of the Cayman Trench

Correction to: The Cayman Crown: newly protected coral reefs at the edge of the Cayman Trench

Coral reef soundscapes and noise

Building back coral reefs requires limiting greenhouse gas emissions, limiting local threats, and active restoration. Vessel noise pollution is a widespread threat acting at a local level impacting a broad range of species from cetaceans to cephalopods. Ultimate consequences of noise pollution include death due to injury or predation, failure to develop and reduced offspring quality and survival. We tested the hypothesis that protecting coral reefs from motorboat noise can improve reproductive output in fish on the Great Barrier Reef in Australia. Across an entire breeding season, we limited motorboat traffic at three separate reefs with breeding spiny chromis. We compared these protected nests with nests on three further reefs where motorboats drove regularly nearby. We replicated the breeding experiment in a laboratory setting to isolate noise as the stimulus. Protecting coral reefs from traffic noise was beneficial for breeding fish and their offspring: egg fanning and offpsring growth were enhanced with lower energetic resource use, and reproductive success was enhanced. Limiting traffic noise at the local level presents a valuable opportunity for enhancing resilience in coral reefs by improving reproductive success in fish. This could speed up recovery following climate related mass mortality events caused by bleaching and cyclones.

Using Fish Remains to Trace Dynamic Exchanges Between Ecology and Economy in Fiji

Island nations in the developing world are some of the communities most at-risk to the effects of climate change and are under increasing pressure from globalized seafood markets. Indigenous Fijians have a stark understanding of environmental change because of their economic and dietary reliance on marine resources, including shark fisheries and tourism. Sharks are important apex predators with deep cultural significance in Fiji and they are thus useful species to focus on when investigating historical ecology. However, they are difficult to study; sharks have cartilaginous skeletons, making full body fossils rare, and their behavior can make them difficult to survey with traditional methods. Sharks are also covered in dermal denticles which they shed throughout their lives and which compose some of the most extensive and oldest fossil types. All fish, including sharks, also shed their teeth, and together these microfossils are called ichthyoliths. Scientists in the Caribbean have developed innovative techniques to use ichthyoliths to illuminate the importance of parrotfish to coral reef ecology and trace historical and pre-anthropogenic shark populations. However, this microfossil approach has not yet reached Fiji. We developed a trait-based character coding scheme to describe denticle morphology based on both modern denticles and fossil denticles and discuss our work to expand current denticle reference collections. When combined with ecological factors, morphological analysis can identify temporal periods and spatial regions of importance in both modern and paleo-ocean ecosystem dynamics and aid historical ecologists in describing shark communities of the past. We are embarking on a research project to collect cores from Fiji to examine parrotfish and shark ecology through time. Here we summarize the methods we will use and how we have tailored them to our study region and invite input from the conservation paleobiology community on our study design.

The Cayman Crown: newly protected coral reefs at the edge of the Cayman Trench

The Cayman Crown: newly protected coral reefs at the edge of the Cayman Trench

Occurrence, bioaccumulation and ecological risk of organic ultraviolet absorbers in multiple coastal and offshore coral communities of the South China Sea

The occurrence of organic ultraviolet absorbers (OUVAs) in coral reef regions has aroused widespread concern. This study focused on the occurrence, distribution, bioaccumulation and ecological risk of ten OUVAs in both coastal and offshore coral reef regions in the South China Sea. While the Σ10OUVAs was 85 % lower in the offshore seawater (15.1 ng/L) than in the coastal seawater (102.1 ng/L), the Σ10OUVAs was 21 % lower in the offshore corals (1.82 μg/g dry weight (dw)) than in the coastal corals (2.31 μg/g dw). This difference was speculated to relate to the high intensity of human activities in the coastal regions. Moreover, the offshore corals showed higher bioaccumulative capability toward OUVAs (log bioaccumulation factors (BAFs): 1.22–5.07) than the coastal corals (log BAFs: 0.17–4.38), which was presumably the influence of varied physiological status under different environmental conditions. The results of the ecological risk assessment showed that BP-3 resulted in 73 % of coastal corals and 20 % of offshore corals at a risk of bleaching. Therefore, the usage and discharge of BP-3 should be managed and controlled by the countries adjacent to the South China Sea for the protection of coral reefs.

Editorial: The role of dimethylsulfide and other sulfur substances on the climate and ecology of coral reefs

Editorial: The role of dimethylsulfide and other sulfur substances on the climate and ecology of coral reefs

A dataset of benthic material distribution of coastal coral reefs in Hainan during 2018–2020

Based on the Sentinel-2 high resolution remote sensing image data, we adopted the object-oriented multi-scale segmentation technology and the nearest neighbor algorithm to classify benthic materials of offshore coral reefs in Wenchang City, Danzhou City, Sanya City of Hainan Province during 2018-2020. Then, combining with the remote sensing images of Gaofen-2 satellite and field validation data we verified the accuracy of the classification results. The dataset can be used to analyze the temporal and spatial changes of benthic materials in coastal coral reefs and assess the health status of coral reefs. Moreover, it can serve as a data foundation for the management and protection of coral reefs in Hainan Island.

Identifying an Evaporative Thermal Refugium for the Preservation of Coral Reefs in a Warming World—The Gulf of Eilat (Aqaba)

AbstractCoral bleaching events are more frequent and severe as global temperatures rise. However, analysis of the surface energy fluxes that substantially affect the thermoregulation of shallow reef environments is rare. Previous work on evaporative cooling in a humid reef environment led to the hypothesis that in proximity to desert regions, drier air enhances evaporative cooling of water overlying coral reefs, reducing the risk of extreme high‐water temperatures. Eddy Covariance measurements made over a shallow desert fringing coral reef in the Gulf of Eilat (Israel) during summer measured evaporation of 10.3 mm d−1 which is maintaining water temperature much lower than the overlying air temperature. In addition, measurements of the most severe marine heatwave that was ever documented in the region are presented as a case study for future reference to the processes that lead to and proceed a marine heatwave, which is induced by synoptic scale events that cause a ∼50% reduction in evaporation rate. Results are compared to similar measurements from a tropical coral reef, where a lower evaporation rate suppressed by higher humidity is unable to offset the heating of water overlying the reef. We conclude that evaporative cooling is a key mechanism protecting coral reefs located in deserts from extreme high‐water temperatures, thereby representing possible thermal refugium for corals against background global warming.

Untapped policy avenues to protect coral reef ecosystems

Coral reefs are experiencing severe decline, and urgent action is required at local and global scales to curb ecosystem loss. Establishing new regulations to protect corals, however, can be time consuming and costly, and it is therefore necessary to leverage existing legal instruments, such as policies originally designed to address terrestrial rather than marine activities, to prevent coral reef degradation. Focusing on the United States, but drawing on successful examples worldwide, we present actionable pathways to increase coral protections under legislation that was originally designed to advance clean freshwater, safe drinking water, and emergency management. We identify specific legal policies and procedures (e.g., industrial permit limits, nonpoint source management incentives, and floodplain restoration programs) that can curb coral reef pollution and can be extended to other countries with similar regulations in place. Coral reef practitioners should consider a broad array of currently underused, actionable, and intersecting environmental policies that can be applied to mitigate coral stress.

MPA-FishMApp – A Citizen Science App That Simplifies Monitoring of Coral Reef Fish Density and Biomass in Marine Protected Areas

Monitoring changes in fish density and biomass inside marine protected areas (MPAs) through fish visual census (FVC) can determine if MPAs are achieving their goal of promoting fish population recovery. Simplified FVC methods have been developed for citizen scientists to enable them to monitor fish populations in MPAs. However, MPA monitoring programs led by local stakeholders remain rare and difficult to sustain due to technical barriers related to FVC data management. Here, we describe and evaluate a novel online app called MPA-FishMApp, which we developed to help stakeholders of MPAs that protect coral reefs in the Philippines efficiently store, analyze, and visualize FVC data. MPA-FishMApp is coupled to a simplified FVC method wherein the observer records only 21 reef fish species groups during surveys. The app provides a simple data entry interface, cloud storage, and algorithms to estimate fish density and biomass. Spatial and temporal trends in fish density and biomass can be instantaneously visualized in the app based on relative importance to fisheries. Field testing suggested that the MPA-FishMApp methodology (simplified FVC and app) is sensitive enough to detect qualitative patterns showing differences in density and biomass that may develop between MPAs and fished sites, especially in fishes that are highly important to fisheries. However, users must have sufficient training and experience in simplified FVC to produce reliable data. MPA-FishMApp may help reverse the lack of monitoring in MPAs across the Philippines and offers an accessible, transparent, and auditable venue for collaboration between citizen scientists and professional scientists.