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Designer reefs and coral probiotics: great concepts but are they good practice?
Abstract
An opinion piece examining opportunities and potential risks of using new technologies in the conservation of coral reef ecosystems.
To cite this article: Michael Sweet, Andrew Ramsey & Mark Bulling (2017): Designer
reefs and coral probiotics: great concepts but are they good practice?, Biodiversity, DOI:
10.1080/14888386.2017.1307786
To link to this article: http://dx.doi.org/10.1080/14888386.2017.1307786
... The manipulation of microbiomes associated with corals (Beneficial Microorganisms for Corals, BMC) [29] was recently proposed as a promising (albeit yet-to-be-explored) tool to improve coral health, potentially promoting resistance and resilience in coral populations and ultimately aiding recovery of impacted reefs [29][30][31][32]. BMCs can enhance coral fitness through their symbiotic relationships with the host, including the cycling of nutrients within the holobiont [33][34][35] or antagonism/exclusion of potential pathogens (biological control) [36][37][38]. ...
... Understanding the influence of the pBMC community at the cellular level is an important next step to elucidate this and other questions. It is currently not known if the pBMCs colonize the host and help to establish a healthy microbiome, thereby preventing a random assembly of the community that could be shifted easily by opportunistic and potentially pathogenic members, i.e., the pathobiome [31]. An alternative explanation would consist of pBMCs providing an additional source of nutrition through heterotrophy and stimulated microbial loops that sustain the corals and prevent bleaching, although Cobetia sp. ...
Although the early coral reef-bleaching warning system (NOAA/USA) is established, there is no feasible treatment that can minimize temperature bleaching and/or disease impacts on corals in the field. Here, we present the first attempts to extrapolate the widespread and well-established use of bacterial consortia to protect or improve health in other organisms (e.g., humans and plants) to corals. Manipulation of the coral-associated microbiome was facilitated through addition of a consortium of native (isolated from Pocillopora damicornis and surrounding seawater) putatively beneficial microorganisms for corals (pBMCs), including five Pseudoalteromonas sp., a Halomonas taeanensis and a Cobetia marina-related species strains. The results from a controlled aquarium experiment in two temperature regimes (26 °C and 30 °C) and four treatments (pBMC; pBMC with pathogen challenge – Vibrio coralliilyticus, VC; pathogen challenge, VC; and control) revealed the ability of the pBMC consortium to partially mitigate coral bleaching. Significantly reduced coral-bleaching metrics were observed in pBMC-inoculated corals, in contrast to controls without pBMC addition, especially challenged corals, which displayed strong bleaching signs as indicated by significantly lower photopigment contents and Fv/Fm ratios. The structure of the coral microbiome community also differed between treatments and specific bioindicators were correlated with corals inoculated with pBMC (e.g., Cobetia sp.) or VC (e.g., Ruegeria sp.). Our results indicate that the microbiome in corals can be manipulated to lessen the effect of bleaching, thus helping to alleviate pathogen and temperature stresses, with the addition of BMCs representing a promising novel approach for minimizing coral mortality in the face of increasing environmental impacts.
... Alteromonadaceae, for example, have repeatedly been shown to colonize the tissues of corals exposed 65 to unfavorable conditions (e.g., increasing water temperatures) ( introducing putative probiotics to other cohabiting organisms and the lack of established 74 methodologies for effective introduction of these microorganisms (Sweet et al., 2017). Chemical 75 microbiome modulators, for example prebiotics, that promote the growth of naturally occurring 76 beneficial microbes, can be a more natural and practical approach to stimulate the growth of 77 beneficial bacterial taxa. ...
Previous observational studies have suggested that terrestrially-derived compounds, most notably humic substances (HS) can protect coral reefs from thermal stress. No study hitherto has, however, tested this hypothesis. In the present study, we used a randomised-controlled microcosm setup to test to what extent HS are able to mitigate the adverse effects of elevated temperature and intense UVB radiation on coral photosynthetic activity, and environmental and host-associated bacterial ercommunities. Our results clearly demonstrate a significant protective effect of HS. Corals in HS-supplemented microcosms had significantly higher photosynthetic activities than those in microcosms subjected to elevated heat and intense UVB radiation. Our results, furthermore, showed that coral reef organisms in HS-supplemented microcosms contained unique bacterial communities enriched with known groups of potentially beneficial bacteria. Our findings have significant repercussions for reef resilience in the face of increasing climate-induced stressors and highlight the importance of restoring coastal forests and the land-sea interface in order to protect coral reefs.
... Being able to completely control environmental factors and thus the development and growth of key microbial groups, combined with the comprehensive use of modern multi-omics technology, will certainly facilitate our understanding of the functions of these microorganisms [131]. Once a stable microbiome engineering approach has been developed, we will be better placed to predict impacts and apply the "product" in a safe and controlled manner [145]. ...
The world’s coral reefs are threatened by the cumulative impacts of global climate change and local stressors. Driven largely by a desire to understand the interactions between corals and their symbiotic microorganisms, and to use this knowledge to eventually improve coral health, interest in coral microbiology and the coral microbiome has increased in recent years. In this review, we summarize the role of the coral microbiome in maintaining a healthy metaorganism by providing nutrients, support for growth and development, protection against pathogens, and mitigation of environmental stressors. We explore the concept of coral microbiome engineering, that is, precise and controlled manipulation of the coral microbiome to aid and enhance coral resilience and tolerance in the changing oceans. Although coral microbiome engineering is clearly in its infancy, several recent breakthroughs indicate that such engineering is an effective tool for restoration and preservation of these valuable ecosystems. To assist with identifying future research targets, we have reviewed the common principles of microbiome engineering and its applications in improving human health and agricultural productivity, drawing parallels to where coral microbiome engineering can advance in the not-too-distant future. Finally, we end by discussing the challenges faced by researchers and practitioners in the application of microbiome engineering in coral reefs and provide recommendations for future work.
... For example, while Cyanobacteria are also highly prevalent in corals [14], very few studies have reported cultured coral-associated Cyanobacteria, and most reported Cyanobacteria are associated with black band disease [87,88]. Cyanobacteria may lend themselves to carbon fixation enhancement through high light stressors, and specific efforts should be made to culture them, using appropriate light and specific culturing media such as BG-11, and ensure that they are not pathogens that would negatively impact coral reefs [89,90]. Overall, the lack of genomic data is hampering culturing efforts, and more culture-independent approaches, such as metagenomics, are needed to assess the specific metabolic needs of coralassociated bacteria. ...
Coral reefs are rapidly declining because of widespread mass coral bleaching causing extensive coral mortality. Elevated seawater temperatures are the main drivers of coral bleaching, and climate change is increasing the frequency and severity of destructive marine heatwaves. Efforts to enhance coral thermal bleaching tolerance can be targeted at the coral host or at coral-associated microorganisms (e.g., dinoflagellate endosymbionts and bacteria). The literature on experimental evolution of bacteria suggests that it has value as a tool to increase coral climate resilience. We provide a workflow on how to experimentally evolve coral-associated bacteria to confer thermal tolerance to coral hosts and emphasize the value of implementing this approach in coral reef conservation and restoration efforts.
... In summary, the application of beneficial microorganisms in coral is promising, and additional mid-and long-term realistic laboratory and well-controlled field pilot experiments are essential to unveil the modulated symbiotic mechanisms, microbiome dynamics, connectivity with other organisms and ecological improvements and outcomes, to indicate and define risk assessment boundaries and provide a safe framework to be applied in light of specific coral reef conditions and urgency for protection and rehabilitaion [80,81]. ...
Background
The coral microbiome plays a key role in host health by being involved in energy metabolism, nutrient cycling, and immune system formation. Inoculating coral with beneficial bacterial consortia may enhance the ability of this host to cope with complex and changing marine environments. In this study, the coral Pocillopora damicornis was inoculated with a beneficial microorganisms for corals (BMC) consortium to investigate how the coral host and its associated microbial community would respond.
Results
High-throughput 16S rRNA gene sequencing revealed no significant differences in bacterial community α-diversity. However, the bacterial community structure differed significantly between the BMC and placebo groups at the end of the experiment. Addition of the BMC consortium significantly increased the relative abundance of potentially beneficial bacteria, including the genera Mameliella and Endozoicomonas. Energy reserves and calcification rates of the coral host were also improved by the addition of the BMC consortium. Co-occurrence network analysis indicated that inoculation of coral with the exogenous BMC consortium improved the physiological status of the host by shifting the coral-associated microbial community structure.
Conclusions
Manipulating the coral-associated microbial community may enhance the physiology of coral in normal aquarium conditions (no stress applied), which may hypothetically contribute to resilience and resistance in this host.
... Also, slow release of cells from a solid support can reduce the need for constant reinoculation. Additionally, immobilized cells will disperse less widely compared with free-living cells, thereby effectively reducing potential issues concerning escaped microorganisms affecting or interacting with nontarget organisms (139). ...
The use of Beneficial Microorganisms for Corals (BMCs) has been proposed recently as a tool for the improvement of coral health, with knowledge in this research topic advancing rapidly. BMCs are defined as consortia of microorganisms that contribute to coral health through mechanisms that include ( a) promoting coral nutrition and growth, ( b) mitigating stress and impacts of toxic compounds, ( c) deterring pathogens, and ( d) benefiting early life-stage development. Here, we review the current proposed BMC approach and outline the studies that have proven its potential to increase coral resilience to stress. We revisit and expand the list of putative beneficial microorganisms associated with corals and their proposed mechanisms that facilitate improved host performance. Further, we discuss the caveats and bottlenecks affecting the efficacy of BMCs and close by focusing on the next steps to facilitate application at larger scales that can improve outcomes for corals and reefs globally.
Expected final online publication date for the Annual Review of Animal Biosciences, Volume 9 is February 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
... Manipulation of the coral microbiome was recently proposed as a promising means to improve coral health by strengthening coral resistance and resilience to environmental stress (Damjanovic et al., 2017;Sweet et al., 2017), and Endozoicomonas has been proposed as an environmental probiotic for this purpose (Peixoto et al., 2017). According to the site-specific distribution of Endozoicomonas, the microbial manipulation in coral would be more effective if we factor in local environmental parameters and host species. ...
The Kuroshio Current (KC) is one of the fastest water currents in the world, running through the western boundary of the North Pacific Ocean. The KC strongly influences the regional hydroclimate by creating temperature, salinity, and pH gradients from tropical to subtropical and temperate zones, including regions with rich coral reef habitats. Microbial community composition of corals is influenced by various environmental factors, including salinity, pH, and geographical location. However, to date, it is unclear how coral-associated microbial communities would respond to the same water current running through different locations with a time lag. Therefore, we hypothesized that the locations subjected to the KC at higher latitudes experience similar but sequential lag in environmental variability compared to those at lower latitudes, and thus the coral communities of both will respond similarly, but at different times. In this year-long study, we compared the bacterial communities of Acropora muricata at Taiwan, Okinawa, and Kochi subjected to the KC. We found that site-specific conditions and site latitude may have stronger effects on bacterial composition and dynamics than a water current. Consequently, we suggest that latitude largely determines the temperature tolerance range of coral microbiota. Additionally, among the dominant coral associated bacteria, Endozoicomonas from A. muricata and Stylophora pistillata forms distinct phylogroups, while Acinetobacter is more likely a host generalist.
... Additionally, genetic engineering targeting the thermotolerance of key symbionts can also enhance the resilience of corals to climate change [99]. Probiotics and genetic engineering may provide a rapid and urgently needed response to coral decline, but it must be noted that the field is in its infancy and substantially more research is needed to understand its efficacy and risks [100]. The potential of using beneficial endolithic microorganisms as probiotics, or the long-term effects of manipulating members of the coral microbiome on the endolithic community, is yet to be studied in detail. ...
Coral microbial ecology is a burgeoning field, driven by the urgency of understanding coral health and slowing reef loss due to climate change. Coral resilience depends on its microbiota, and both the tissue and the underlying skeleton are home to a rich biodiversity of eukaryotic, bacterial and archaeal species that form an integral part of the coral holobiont. New techniques now enable detailed studies of the endolithic habitat, and our knowledge of the skeletal microbial community and its eco-physiology is increasing rapidly, with multiple lines of evidence for the importance of the skeletal microbiota in coral health and functioning. Here, we review the roles these organisms play in the holobiont, including nutritional exchanges with the coral host and decalcification of the host skeleton. Microbial metabolism causes steep physico-chemical gradients in the skeleton,
... New techniques have recently been developed that enable large scale production of sexually produced coral spat for just such scenarios 17 . This could then be linked into current more elaborate attempts around reef restoration including practices such as assisted gene flow 18,19 , hybridisation 20 and the use of coral probiotics 21,22 . When coupled with the advancements in settlement substrates 23 -upscaling seems to be within reach. ...
Reef restoration efforts, utilising sexual coral propagation need up-scaling to have ecologically meaningful impact. Post-settlement survival bottlenecks, in part due to competitive benthic algae interactions should be addressed, to improve productivity for these initiatives. Sea urchins are keystone grazers in reef ecosystems, yet feeding behaviour of adults causes physical damage and mortality to developing coral spat. To investigate if microherbivory can be utilised for co-culture, we quantitatively assessed how varying densities of juvenile sea urchins Mespilia globulus (Linnaeus, 1758), reared alongside the coral Acropora millepora (Ehrenberg, 1834) effected survival and growth of coral recruits. Spawning of both species were induced ex situ. A comparison of A. millepora spat reared in three M. globulus densities (low 16.67 m−2, medium 37.50 m−2, high 75.00 m−2) and a non-grazed control indicated coral survival is significantly influenced by grazing activity (p < 0.001) and was highest in the highest density treatment (39.65 ± 10.88%, mean ± s.d). Urchin grazing also significantly (p < 0.001) influenced coral size (compared to non-grazing control), with colonies in the medium and high-densities growing the largest (21.13 ± 1.02 mm & 20.80 ± 0.82, mean ± s.e.m). Increased urchin density did however have a negative influence on urchin growth, a result of limited food availability.
... Additionally, genetic engineering targeting the thermotolerance of key symbionts can also enhance the resilience of corals to climate change [99]. Probiotics and genetic engineering may provide a rapid and urgently needed response to coral decline, but it must be noted that the field is in its infancy and substantially more research is needed to understand its efficacy and risks [100]. The potential of using beneficial endolithic microorganisms as probiotics, or the long-term effects of manipulating members of the coral microbiome on the endolithic community, is yet to be studied in detail. ...
Coral microbial ecology is a burgeoning field, driven by the urgency of understanding coral health and slowing reef loss due to climate change. Coral resilience depends on its microbiota, and both the tissue and the underlying skeleton are home to a rich biodiversity of eukaryotic, bacterial and archaeal species that form an integral part of the coral holobiont. New techniques now enable detailed studies of the endolithic habitat, and our knowledge of the skeletal microbial community and its eco-physiology is increasing rapidly, with multiple lines of evidence for the importance of the skeletal microbiota in coral health and functioning. Here, we review the roles these organisms play in the holobiont, including nutritional exchanges with the coral host and decalcification of the host skeleton. Microbial metabolism causes steep physico-chemical gradients in the skeleton, creating micro-niches that, along with dispersal limitation and priority affects, define the fine-scale microbial community assembly. Coral bleaching causes drastic changes in the skeletal microbiome, which can mitigate bleaching effects and promote coral survival during stress periods, but may also have detrimental effects. Finally, we discuss the idea that the skeleton may function as a microbial reservoir that can promote recolonization of the tissue microbiome following dysbiosis and help the coral holobiont return to homeostasis.
... Some authors have the purpose of identifying the pathogen, fulfilling the postulates of Köch (Puyana et al., 2015). For the identification of pathogens, the most commonly used techniques are microbiology and molecular biology like Polymerase Chain Reaction (PCR) because of their simplicity, low cost, and reliability of results (Sweet et al., 2017). The study of the different diseases that are presented in corals is of international concern. ...
Reefs are the most biologically diverse marine ecosystems; therefore, to conserve the vast array of marine species that depend on them is vital. Many coral reefs around the world are under threat of extinction due to factors related to climate change and anthropogenic action. Studies have shown that specific infections develop at normal ocean temperatures and that warmer temperatures make the disease even more virulent. Also, as temperature increases, the infection in already infected corals becomes lethal. Thermal stress and the presence of pathogenic bacteria from the contribution of organic matter generates pathological affections in coral tissue, such as the White Band, Black Band, Yellow Band, White Plague, and Bacterial Whitening. This stimulates, in the short term, loss of coral cover and in the long term, negative impacts on the faunal composition of marine ecosystems. This review aims to present scientific information generated in the identification of different pathogenic bacteria that affect the health of corals.
Coral reefs worldwide are suffering rapid deterioration as a consequence of numerous anthropogenic disturbances, with climate change being the biggest threat to these magnificent ecosystems. While it is critical that the root causes of climate change are addressed, many coral reef scientists, managers, and other stakeholders support the development and safe implementation of innovative coral reef restoration activities which may help ensure coral reefs persist into the future. These interventions include bioengineering approaches aimed at enhancing coral thermal bleaching tolerance, such as selective breeding and the manipulation of coral-associated microbes. This chapter provides an overview of the field of microbiome manipulation in corals, critically synthesizes its state of play, and provides direction for progressing the field including the value of omics approaches.
Despite the great ecological and economic importance of coral reefs, these ecosystems are especially sensitive to environmental changes and vulnerable to impacts from various anthropogenic activities, including contamination by oil spills. Oil spills occur worldwide, mostly in marine environments, and have been reported for decades. Furthermore, the main oil transport routes in the oceans are close to important coral reefs and many of the major oil spills in history have occurred near these areas. Because of the widespread use of petroleum products, offshore oil and gas production has significantly increased its potential since the 1990s, thus increasing the risk of accidents in marine environments and consequently on coral reefs. Despite the great risk of oil exploitation to coral reefs, there is still no efficient, sustainable, and large-scale applicable remediation strategy to protect or to clean up reefs impacted by oil spills. Current methodologies to remediate oil pollution in marine environments are based on the use of chemical dispersants; however, these can be more harmful to corals than oil itself. Meanwhile, the use of bioremediation strategy, through the manipulation of the coral microbiome, has been proposed as a possible alternative to mitigate the impacts of oil on coral reefs.
The ocean is the largest ecosystem on Earth and is vital for human well-being. It is however greatly impacted by a range of pressures coming from human activities, such as pollution including oil spills, plastics, and endocrine-disrupting chemicals. Most critically, the ocean is being altered by climate change leading to ocean warming, sea-level rise, and ocean acidification. Their cumulative impact is putting further strain on many marine species and habitats. The health and resilience of marine ecosystems are severely compromised by all these pressures and large-scale ecological restoration is urgently needed to rebuild the ocean. New approaches are needed and a major aspect and focus of this chapter are giving an overview of some of the latest developments in the strategic use of the marine microbiome in ocean restoration. Thanks to scientific research there is a better understanding of the importance of the microbiome in maintaining ecosystem health and enhancing resilience. It is crucial to recognize the valuable role of the marine microbiome in ocean restoration. This book chapter aims to outline present state-of-the-art scientific, current policy and governance, and communication developments around the marine microbiome with the hope to inform and support the development of effective management strategies of the marine microbiome for sustainable ocean restoration.
In the past 20 years, a new concept has slowly emerged and expanded to various domains of marine biology research: the holobiont. A holobiont describes the consortium formed by a eukaryotic host and its associated microorganisms including bacteria, archaea, protists, microalgae, fungi, and viruses. From coral reefs to the deep-sea, symbiotic relationships and host-microbiome interactions are omnipresent and central to the health of marine ecosystems. Studying marine organisms under the light of the holobiont is a new paradigm that impacts many aspects of marine sciences. This approach is an innovative way of understanding the complex functioning of marine organisms, their evolution, their ecological roles within their ecosystems, and their adaptation to face environmental changes. This review offers a broad insight into key concepts of holobiont studies and into the current knowledge of marine model holobionts. Firstly, the history of the holobiont concept and the expansion of its use from evolutionary sciences to other fields of marine biology will be discussed. Then, the ecology and physiology of marine holobionts will be investigated through the examples of corals and sponges. We will discuss the impacts of environmental change on organisms at the holobiont level and how microbiomes contribute to the resilience and/or vulnerability of their host in the face of environmental stressors. Finally, we will conclude with the development of new technologies, holistic approaches, and future prospects for conservation biology surrounding marine holobionts.
For millennia, coastal and marine ecosystems have adapted and flourished in the Red Sea’s unique environment. Surrounded by deserts on all sides, the Red Sea is subjected to high dust inputs and receives very little freshwater input, and so harbors a high salinity. Coral reefs, seagrass meadows, and mangroves flourish in this environment and provide socio-economic and environmental benefits to the bordering coastlines and countries. Interestingly, while coral reef ecosystems are currently experiencing rapid decline on a global scale, those in the Red Sea appear to be in relatively better shape. That said, they are certainly not immune to the stressors that cause degradation, such as increasing ocean temperature, acidification and pollution. In many regions, ecosystems are already severely deteriorating and are further threatened by increasing population pressure and large coastal development projects. Degradation of these marine habitats will lead to environmental costs, as well as significant economic losses. Therefore, it will result in a missed opportunity for the bordering countries to develop a sustainable blue economy and integrate innovative nature-based solutions. Recognizing that securing the Red Sea ecosystems’ future must occur in synergy with continued social and economic growth, we developed an action plan for the conservation, restoration, and growth of marine environments of the Red Sea. We then investigated the level of resources for financial and economic investment that may incentivize these activities. This study presents a set of commercially viable financial investment strategies, ecological innovations, and sustainable development opportunities, which can, if implemented strategically, help ensure long-term economic benefits while promoting environmental conservation. We make a case for investing in blue natural capital and propose a strategic development model that relies on maintaining the health of natural ecosystems to safeguard the Red Sea’s sustainable development.
Coral-associated microorganisms are essential for maintaining the health of the coral holobiont by participating in nutrient cycling and protecting the coral host from pathogens. Under stressful conditions, disruption of the coral prokaryotic microbiome is linked to increased susceptibility to diseases and mortality. Inoculation of corals with beneficial microbes could confer enhanced stress tolerance to the host and may be a powerful tool to help corals thrive under challenging environmental conditions. Here, we explored the feasibility of coral early life stage microbiome manipulation by repeatedly inoculating coral recruits with a bacterial cocktail generated in the laboratory. Co-culturing the two species Acropora tenuis and Platygyra daedalea allowed us to simultaneously investigate the effect of host factors on the coral microbiome. Inoculation cocktails were regularly prepared from freshly grown pure bacterial cultures, which were hence assumed viable, and characterized via the optical density measurement of each individual strain put in suspension. Coral early recruits were inoculated seven times over 3 weeks and sampled once 36 h following the last inoculation event. At this time point, the cumulative inoculations with the bacterial cocktails had a strong effect on the bacterial community composition in recruits of both coral species. While the location of bacterial cells within the coral hosts was not assessed, metabarcoding using the 16S rRNA gene revealed that two and six of the seven bacterial strains administered through the cocktails were significantly enriched in inoculated recruits of A. tenuis and P. daedalea, respectively, compared to control recruits. Despite being reared in the same environment, A. tenuis and P. daedalea established significantly different bacterial communities, both in terms of taxonomic composition and diversity measurements. These findings indicate that coral host factors as well as the environmental bacterial pool play a role in shaping coral-associated bacterial community composition. Host factors may include microbe transmission mode (horizontal versus maternal) and host specificity. While the long-term stability of taxa included in the bacterial inocula as members of the host-associated microbiome remains to be evaluated, our results provide support for the feasibility of coral microbiome manipulation, at least in a laboratory setting.
The majority of research focusing on coral reproductive biology (e.g. spawning timing and synchrony) is carried out in facilities adjacent to reefs that the corals originated from. This is in part because transporting corals over long distances by air leads to sub-lethal stress that may confound the results of any experimental study. However, these constraints often mean research associated with coral reproductive timing is restricted to relatively few locations. To assess the potential for studying environmental drivers of spawning timing in corals in captivity (defined here as ex-situ closed aquaria), 14 large (16-37 cm) Acropora hyacinthus colonies were transported from reefs in Singapore to a closed aquarium system in London (a journey time of ~34 hours). Collection was purposefully timed to occur just before the predicted annual mass spawning event and on the day of transportation it was noted that 12 of the 14 corals contained large visible oocytes. The 'inverted submersion method' was applied and the water used for transport was buffered to ensure the colonies remained healthy throughout their travel time. At the end location, all colonies were placed in a purpose-built aquarium research system which allowed for the approximation of the environmental conditions found on the fringing reefs south of Singapore (the original location). While three colonies appeared partially bleached (visibly pale) and one colony suffered from partial tissue loss, all colonies (i.e. 100% of those collected) were still alive at the time of writing (28 months post collection). More importantly, all corals that were gravid at the time of collection spawned ex situ within the same lunar month as those in the wild (within 3-4 nights of each other). This paper describes the procedures for carrying out long distance transportation of large gravid broadcast spawning coral colonies from reef sites to public aquariums or research facilities around the world for the purpose of ex-situ spawning research.
The symbiotic association between the coral animal and its endosymbiotic dinoflagellate partner Symbiodinium is central to the success of corals. However, an array of other microorganisms associated with coral (i.e., Bacteria, Archaea, Fungi, and viruses) have a complex and intricate role in maintaining homeostasis between corals and Symbiodinium. Corals are sensitive to shifts in the surrounding environmental conditions. One of the most widely reported responses of coral to stressful environmental conditions is bleaching. During this event, corals expel Symbiodinium cells from their gastrodermal tissues upon experiencing extended seawater temperatures above their thermal threshold. An array of other environmental stressors can also destabilize the coral microbiome, resulting in compromised health of the host, which may include disease and mortality in the worst scenario. However, the exact mechanisms by which the coral microbiome supports coral health and increases resilience are poorly understood. Earlier studies of coral microbiology proposed a coral probiotic hypothesis, wherein a dynamic relationship exists between corals and their symbiotic microorganisms, selecting for the coral holobiont that is best suited for the prevailing environmental conditions. Here, we discuss the microbial-host relationships within the coral holobiont, along with their potential roles in maintaining coral health. We propose the term BMC (Beneficial Microorganisms for Corals) to define (specific) symbionts that promote coral health. This term and concept are analogous to the term Plant Growth Promoting Rhizosphere (PGPR), which has been widely explored and manipulated in the agricultural industry for microorganisms that inhabit the rhizosphere and directly or indirectly promote plant growth and development through the production of regulatory signals, antibiotics and nutrients. Additionally, we propose and discuss the potential mechanisms of the effects of BMC on corals, suggesting strategies for the use of this knowledge to manipulate the microbiome, reversing dysbiosis to restore and protect coral reefs. This may include developing and using BMC consortia as environmental “probiotics” to improve coral resistance after bleaching events and/or the use of BMC with other strategies such as human-assisted acclimation/adaption to shifting environmental conditions.
Coral reefs across the world’s oceans are in the midst of the longest bleaching event on record (from 2014 to at least 2016). As many of the world’s reefs are remote, there is limited information on how past thermal conditions have influenced reef composition and current stress responses. Using satellite temperature data for 1985–2012, the analysis we present is the first to quantify, for global reef locations, spatial variations in warming trends, thermal stress events and temperature variability at reef-scale (~4 km). Among over 60,000 reef pixels globally, 97% show positive SST trends during the study period with 60% warming significantly. Annual trends exceeded summertime trends at most locations. This indicates that the period of summer-like temperatures has become longer through the record, with a corresponding shortening of the ‘winter’ reprieve from warm temperatures. The frequency of bleaching-level thermal stress increased three-fold between 1985–91 and 2006–12 – a trend climate model projections suggest will continue. The thermal history data products developed enable needed studies relating thermal history to bleaching resistance and community composition. Such analyses can help identify reefs more resilient to thermal stress.
The spread of amphibian chytrid fungus, Batrachochytrium dendrobatidis , is associated with the emerging infectious wildlife disease chytridiomycosis. This fungus poses an overwhelming threat to global amphibian biodiversity and is contributing toward population declines and extinctions worldwide. Extremely low host-species specificity potentially threatens thousands of the 7,000+ amphibian species with infection, and hosts in additional classes of organisms have now also been identified, including crayfish and nematode worms.
Soon after the discovery of B. dendrobatidis in 1999, it became apparent that this pathogen was already pandemic; dozens of countries and hundreds of amphibian species had already been exposed. The timeline of B. dendrobatidis ’s global emergence still remains a mystery, as does its point of origin. The reason why B. dendrobatidis seems to have only recently increased in virulence to catalyze this global disease event remains unknown, and despite 15 years of investigation, this wildlife pandemic continues primarily uncontrolled. Some disease treatments are effective on animals held in captivity, but there is currently no proven method to eradicate B. dendrobatidis from an affected habitat, nor have we been able to protect new regions from exposure despite knowledge of an approaching “wave” of B. dendrobatidis and ensuing disease.
International spread of B. dendrobatidis is largely facilitated by the commercial trade in live amphibians. Chytridiomycosis was recently listed as a globally notifiable disease by the World Organization for Animal Health, but few countries, if any, have formally adopted recommended measures to control its spread. Wildlife diseases continue to emerge as a consequence of globalization, and greater effort is urgently needed to protect global health.
Although coral reefs support the largest concentrations of marine biodiversity worldwide, the extent to which the global system of marine-protected areas (MPAs) represents individual species and the breadth of evolutionary history across the Tree of Life has never been quantified. Here we show that only 5.7% of scleractinian coral species and 21.7% of labrid fish species reach the minimum protection target of 10% of their geographic ranges within MPAs. We also estimate that the current global MPA system secures only 1.7% of the Tree of Life for corals, and 17.6% for fishes. Regionally, the Atlantic and Eastern Pacific show the greatest deficit of protection for corals while for fishes this deficit is located primarily in the Western Indian Ocean and in the Central Pacific. Our results call for a global coordinated expansion of current conservation efforts to fully secure the Tree of Life on coral reefs.
The genetic enhancement of wild animals and plants for characteristics that benefit human populations has been practiced for thousands of years, resulting in impressive improvements in commercially valuable species. Despite these benefits, genetic manipulations are rarely considered for noncommercial purposes, such as conservation and restoration initiatives. Over the last century, humans have driven global climate change through industrialization and the release of increasing amounts of CO2, resulting in shifts in ocean temperature, ocean chemistry, and sea level, as well as increasing frequency of storms, all of which can profoundly impact marine ecosystems. Coral reefs are highly diverse ecosystems that have suffered massive declines in health and abundance as a result of these and other direct anthropogenic disturbances. There is great concern that the high rates, magnitudes, and complexity of environmental change are overwhelming the intrinsic capacity of corals to adapt and survive. Although it is important to address the root causes of changing climate, it is also prudent to explore the potential to augment the capacity of reef organisms to tolerate stress and to facilitate recovery after disturbances. Here, we review the risks and benefits of the improvement of natural and commercial stocks in noncoral reef systems and advocate a series of experiments to determine the feasibility of developing coral stocks with enhanced stress tolerance through the acceleration of naturally occurring processes, an approach known as (human)-assisted evolution, while at the same time initiating a public dialogue on the risks and benefits of this approach.
Captive and wild frogs from North and Central America and Australia recently have died with epidermal infections by chytridiomycete fungi. We isolated a chytridiomycete into pure culture from a captive, blue poison dart frog that died at the National Zoological Park in Washington, D.C. Using this isolate, we photographed developmental stages on nutrient agar, examined zoospores with transmission electron microscopy, and inoculated test frogs. This inoperculate chytrid develops either monocentrically or colonially and has thread-like rhizoids that arise from single or multiple areas on the developing zoosporangium. The taxonomically important features of the kinetosomal region of the zoospore indicate that this chytrid is a member of the Chytridiales but differs from other chytrids studied with transmission electron microscopy. Its microtubule root, which begins at kinetosome triplets 9-1 and extends parallel to the kinetosome into the aggregation of ribosomes, is distinctive. Histologic examination of test frogs revealed that the pure culture infected the skin of test frogs, whereas the skin of control frogs remained free of infection. The fungus is described as Batrachochytrium dendrobatidis gen. et sp. nov.
The fitness costs of disease resistance in plants are reviewed and their relevance to plant breeding is discussed. An important theme of current research is that plant defence is closely integrated into pathways that regulate growth and development in plants, so mutations in genes with central locations in defence networks often have numerous pleiotropic effects. There is increasing evidence that resistance to one disease involves trade-offs with responses to other bio-antagonists; the numerous pleiotropic effects of mlo resistance to powdery mildew of barley are discussed as an example. There is a striking contrast between the low costs of resistance in most crop diseases and the sometimes high costs of resistance in model systems studied in fundamental research. It is suggested that, through natural and artificial selection over thousands of years, farmers and more recently plant breeders have selected alleles which maximize the benefits and minimize the costs of resistance. There is sometimes substantial genotype-by-environment interaction in fitness costs, which makes experiments on fitness in plants especially challenging, but it is essential to understand these interactions to appreciate the relevance of fitness costs and trade-offs to crops in field conditions. It is proposed that in the great majority of cases, in which it is not feasible to investigate fitness costs and their interactions with the environment in depth, plant breeding is an efficient way of incorporating genes with benefits which exceed any costs into commercially successful cultivars of arable crops.
Coral reef restoration has gained recent popularity in response to the steady decline of corals and the recognition that coral reefs may not be able to recover naturally without human intervention. To synthesize collective knowledge about reef restoration focused particularly on the threatened genus Acropora in the Caribbean and western Atlantic, we conducted a literature review combined with personal communications with restoration practitioners and an online questionnaire to identify the most effective reef restoration methods and the major obstacles hindering restoration success. Most participants (90%) strongly believe that Acropora populations are severely degraded, continue to decline, and may not recover without human intervention. Low-cost methods such as coral gardening and fragment stabilization were ranked as the most effective restoration activities for this genus. High financial costs, the small footprint of restoration activities, and the potential damage to wild populations were identified as major concerns, while increased public awareness and education were ranked as the highest benefits of coral reef restoration. This study highlights the advantages and outlines the concerns associated with coral reef restoration and creates a unique synthesis of coral restoration activities as a complementary management tool to help guide “best-practices” for future restoration efforts throughout the region.
The invasion of western Atlantic marine habitats by two predatory Indo-Pacific lionfish, Pterois volitans and P. miles, has recently unfolded at an unprecedented rate, with ecological consequences anticipated to be largely negative. We take stock of recently accumulated knowledge about lionfish ecology and behaviour and examine how this information is contributing to our general understanding of the patterns and processes underpinning marine predator invasions, and to the specific issue of lionfish management. Lionfish were first reported off Florida in 1985. Since their establishment in The Bahamas in 2004, they have colonised 7.3 million km2 of the western Atlantic and Caribbean region, and populations have grown exponentially at many locations. These dramatic increases potentially result from a combination of life-history characteristics of lionfish, including early maturation, early reproduction, anti-predatory defenses, unique predatory behaviour, and ecological versatility, as well as features of the recipient communities, including prey naïveté, weak competitors, and native predators that are overfished and naïve to lionfish. Lionfish have reduced the abundance of small native reef fishes by up to 95% at some invaded sites. Population models predict that culling can reduce lionfish abundance substantially, but removal rates must be high. Robust empirical estimates of the cost-effectiveness and effects of removal strategies are urgently needed because lionfish management will require a long-term, labour-intensive effort that may be possible only at local scales. The ultimate causes of the invasion were inadequate trade legislation and poor public awareness of the effects of exotic species on marine ecosystems. The lionfish invasion highlights the need for prevention, early detection, and rapid response to marine invaders.
The role of corallivory is becoming increasingly recognised as an important factor in coral health at a time when coral reefs around the world face a number of other stressors. The polyclad flatworm, Amakusaplana acroporae, is a voracious predator of Indo-Pacific acroporid corals in captivity, and its inadvertent introduction into aquaria has lead to the death of entire coral colonies. While this flatworm has been a pest to the coral aquaculture community for over a decade, it has only been found in aquaria and has never been described from the wild. Understanding its biology and ecology in its natural environment is crucial for identifying viable biological controls for more successful rearing of Acropora colonies in aquaria, and for our understanding of what biotic interactions are important to coral growth and fitness on reefs. Using morphological, histological and molecular techniques we determine that a polyclad found on Acropora valida from Lizard Island, Australia is A. acroporae. The presence of extracellular Symbiodinium in the gut and parenchyma and spirocysts in the gut indicates that it is a corallivore in the wild. The examination of a size-range of individuals shows maturation of the sexual apparatus and increases in the number of eyes with increased body length. Conservative estimates of abundance show that A. acroporae occurred on 7 of the 10 coral colonies collected, with an average of 2.6±0.65 (mean ±SE) animals per colony. This represents the first report of A. acroporae in the wild, and sets the stage for future studies of A. acroporae ecology and life history in its natural habitat.
The global emergence and spread of the pathogenic, virulent, and highly transmissible fungus Batrachochytrium dendrobatidis, resulting in the disease chytridiomycosis, has caused the decline or extinction of up to about 200 species of frogs. Key
postulates for this theory have been completely or partially fulfilled. In the absence of supportive evidence for alternative
theories despite decades of research, it is important for the scientific community and conservation agencies to recognize
and manage the threat of chytridiomycosis to remaining species of frogs, especially those that are naive to the pathogen.
The impact of chytridiomycosis on frogs is the most spectacular loss of vertebrate biodiversity due to disease in recorded
history.
Coral bleaching events vary in severity, however, to date, the hierarchy of susceptibility to bleaching among coral taxa has been consistent over a broad geographic range and among bleaching episodes. Here we examine the extent of spatial and temporal variation in thermal tolerance among scleractinian coral taxa and between locations during the 2010 thermally induced, large-scale bleaching event in South East Asia.
Surveys to estimate the bleaching and mortality indices of coral genera were carried out at three locations with contrasting thermal and bleaching histories. Despite the magnitude of thermal stress being similar among locations in 2010, there was a remarkable contrast in the patterns of bleaching susceptibility. Comparisons of bleaching susceptibility within coral taxa and among locations revealed no significant differences between locations with similar thermal histories, but significant differences between locations with contrasting thermal histories (Friedman = 34.97; p<0.001). Bleaching was much less severe at locations that bleached during 1998, that had greater historical temperature variability and lower rates of warming. Remarkably, Acropora and Pocillopora, taxa that are typically highly susceptible, although among the most susceptible in Pulau Weh (Sumatra, Indonesia) where respectively, 94% and 87% of colonies died, were among the least susceptible in Singapore, where only 5% and 12% of colonies died.
The pattern of susceptibility among coral genera documented here is unprecedented. A parsimonious explanation for these results is that coral populations that bleached during the last major warming event in 1998 have adapted and/or acclimatised to thermal stress. These data also lend support to the hypothesis that corals in regions subject to more variable temperature regimes are more resistant to thermal stress than those in less variable environments.
The coral holobiont model highlights the integral role bacteria play in the health of reefbuilding corals. Documenting the natural diversity of bacterial communities within, and closely associated with, coral tissues provides information on the diversity, interaction and roles of bacteria to the function of reef-building corals. Fluorescence in situ hybridisation was used to visualise bacterial communities closely associated with the tissues of experimentally manipulated reef corals to determine how tissue-associated coral-bacterial interactions vary from normal associations in apparently healthy reef corals, to those occurring in controlled and thermally stressed experimental conditions. Branches of 2 coral species of the Great Barrier Reef, Acropora aspera and Stylophora pistillata, were collected from reefs adjacent to Heron Island and were maintained in controlled outdoor flowthrough aquaria conditions. Following acclimation, the branches were stressed using elevated temperatures to investigate the in situ (within-tissue) bacterial community changes. In situ bacterial community dynamics were found to vary not only due to maintenance within the aquaria conditions, but also following coral bleaching. An aggregation of rod-shaped γ-proteobacteria was evident within the gastrodermis of corals regardless of health or bleaching status, consistent with aggregations described within other coral species. However, bacterial colonisation of the tissues occurred only following the temperature-induced bleaching of the coral tissues. This study demonstrates that the natural bacterial communities of corals are severely altered during stress associated with experimental and field conditions, which suggests a potential mechanism for the link between disease and stresses arising from global warming.
The microbial biota dwelling in the mucus, on the surface, and in the tissues of many coral species may have an important role in holobiont physiology and health. This microbiota differs with coral species, water depth, and geographic location. Here we compare the surface mucus microbiota of the coral Fungia granulosa from the natural environment with that from individuals maintained in aquaria. Molecular analysis revealed that the microbial community of the mucus microlayer of the coral F. granulosa includes a wide range of bacteria and that these change with environment. Coral mucus from the natural environment contained a significantly higher diversity of microorganisms than did mucus from corals maintained in the closed-system aquaria. A microbial community shift, with the loss of several groups, including actinobacterial and cyanobacterial groups, was observed in corals maintained in aquaria. The most abundant bacterial class in F. granulosa mucus was the Alphaproteobacteria, regardless of whether the corals were from aquaria or freshly collected from their natural environment. A significantly higher percentage of bacteria from the Betaproteobacteria class was evident in aquarium corals (24%) when compared with corals from the natural environment (3%). The differences in mucus-inhabiting microbial communities between corals from captive and natural environments suggest an adaptation of the mucus bacterial communities to the different conditions.
Captive and wild frogs from North and Central America and Australia recently have died with epidermal infections by chytridiomycete fungi. We isolated a chytridiomycete into pure culture from a captive, blue poison dart frog that died at the National Zoological Park in Washington, D.C. Using this isolate, we photographed developmental stages on nutrient agar, examined zoospores with transmission electron microscopy, and inoculated test frogs. This inoperculate chytrid develops either monocentrically or colonially and has thread-like rhizoids that arise from single or multiple areas on the developing zoo-sporangium. The taxonomically important features of the kinetosomal region of the zoospore indicate that this chytrid is a member of the Chytridiales but differs from other chytrids studied with transmission electron microscopy. Its microtubule root, which begins at kinetosome triplets 9–1 and extends parallel to the kinetosome into the aggregation of ribosomes, is distinctive. Histologic examination of test frogs revealed that the pure culture infected the skin of test frogs, whereas the skin of control frogs remained free of infection. The fungus is described as Batrachochytrium, dendrobatidis gen. et sp. nov.
Large marine protected areas are increasingly being established to meet global conservation targets and promote sustainable use of resources. Although the factors affecting the performance of small-scale marine protected areas are relatively well studied, there is no such body of knowledge for large marine protected areas. We conducted a global meta-analysis to systematically investigate social, ecological, and governance characteristics of successful large marine protected areas with respect to several social and ecological outcomes. We included all large (>10,000 km²), implemented (>5 years of active management) marine protected areas that had sufficient data for analysis, for a total of twelve cases. We used the Social-Ecological Systems Meta-Analysis Database, and a consistent protocol for using secondary data and key informant interviews, to code proxies for fisheries, ecosystem health, and the wellbeing of user groups (mainly fishers). We tested four sets of hypotheses derived from the literature on small-scale marine protected areas and common-pool resources: (i) the attributes of species and ecosystems to be managed in the marine protected area, (ii) adherence to principles for designing small-scale marine protected areas, (iii) adherence to the design principles for common-pool resource management, and (iv) stakeholder participation. We found varying levels of support for these hypotheses. Improved fisheries were associated with older marine protected areas, and higher levels of enforcement. Declining fisheries were associated with several ecological and economic factors, including low productivity, high mobility, and high market value. High levels of participation were correlated with improvements in wellbeing and ecosystem health trends. Overall, this study constitutes an important first step in identifying factors affecting social wellbeing and ecological performance of large marine protected areas.
The term " microbiome " was first coined in 1988 and given the definition of a characteristic microbial community occupying a reasonably well defined habitat which has distinct physio-chemical properties. A more recent term has also emerged, taking this one step further and focusing on diseases in host organisms. The " pathobiome " breaks down the concept of " one pathogen = one disease " and highlights the role of the microbiome, more specifically certain members within the microbiome, in causing pathogenesis. The development of next generation sequencing has allowed large data sets to be amassed describing the microbial communities of many organisms and the field of coral biology is no exception. However, the choices made in the analytical process and the interpretation of these data can significantly affect the outcome and the overall conclusions drawn. In this review we explore the implications of these difficulties, as well as highlighting analytical tools developed in other research fields (such as network analysis) which hold substantial potential in helping to develop a deeper understanding of the role of the microbiome in disease in corals. We also make the case that standardization of methods will substantially improve the collective gain in knowledge across research groups.
The number of ecophysiological studies involving reef corals has increased markedly over the last 20 years, driven primarily by the concern over the potential effects of anthropogenic change on coral communities. In particular, the evaluation of the effects of global climate change has prompted major research efforts into understanding the consequences of both rising seawater temperatures and ocean acidification on the physiology of corals. In recent years the recognition that corals harbour not only symbiotic algae but also a diverse microbial consortium, which may both influence and be influenced by the physiology of the animal host, has added an extra layer of complexity to this biological system known collectively as the 'coral holobiont'. The present review draws together an extensive literature on ecophysiological responses of the coral holobiont to anthropo-genic change, with specific references to the latest molecular and genetic developments in the field. It also highlights gaps in our basic understanding of coral physiology and draws attention to the value of extreme physical habitats in elucidating the acclimatory and adaptive scope of reef corals to climate change.
Incidences of coral disease are increasing. Most studies which focus on diseases in these organisms routinely assess variations in bacterial associates. However, other microorganism groups such as viruses, fungi and protozoa are only recently starting to receive attention. This study aimed at assessing the diversity of ciliates associated with coral diseases over a wide geographical range. Here we show that a wide variety of ciliates are associated with all nine coral diseases assessed. Many of these ciliates such as Trochilia petrani and Glauconema trihymene feed on the bacteria which are likely colonizing the bare skeleton exposed by the advancing disease lesion or the necrotic tissue itself. Others such as Pseudokeronopsis and Licnophora macfarlandi are common predators of other protozoans and will be attracted by the increase in other ciliate species to the lesion interface. However, a few ciliate species (namely Varistrombidium kielum, Philaster lucinda, P. guamensis, a Euplotes sp., a Trachelotractus sp. and a Condylostoma sp.) appear to harbor symbiotic algae, potentially from the coral themselves, a result which may indicate they play some role in the disease pathology at the very least. Although, from this study alone we are not able to discern what roles any of these ciliates play in disease causation, the consistent presence of such communities with disease lesion interfaces warrants further investigation.
Large-scale rearing of coral larvae during mass spawning events and subsequent direct introduction of competent larvae onto denuded reefs ('larval seeding') has been proposed as a low-tech and affordable way of enhancing coral settlement and hence recovery of degraded reefs. While some studies have shown positive short-term effects on settlement, to date, none have examined the long-term effects of larval seeding for a broadcast-spawning coral. Here, we test whether larval seeding significantly increases coral recruitment rates both in the short (5 wk) and longer (∼6 mo to 1 yr) term. Larvae of Acropora digitifera were reared ex situ, and ∼1 million larvae were introduced to 7 artificial reefs (ARs) while 7 others were left unseeded. Settlement tiles deployed on both seeded and control ARs were retrieved for examination 5 and 30 wk after seeding. In addition, the presence of visible coral recruits on the AR surfaces was monitored before and for ∼13 mo post-seeding. Density of acroporid spat was significantly higher on seeded tiles than on controls 5 wk after seeding, but this effect had vanished by 30 wk. Comparison of the densities of new visible Acropora recruits between seeded and control ARs showed no significant difference ∼13 mo after seeding. Larval seeding therefore had no long-term effect due to high post-settlement mortality (which appeared to be density-related). Results suggest that reef-rehabilitation methods that aim to harness coral sexual reproduction might better focus on rearing juveniles through early post-settlement mortality bottlenecks.
In most tropical countries, coral reef ecosystems provide many goods and services to coastal populations. A variety of anthropogenic practices threatens reef health and therefore jeopardizes the benefits flowing from these services and goods. These threats range from local pollution, sedimentation, destructive fishing practices and coral mining to global issues like coral bleaching. Economic valuation can help to shed light to the importance of the services and goods by 'getting some of the numbers on the table'. And creating markets for sustainable resource utilization can enhance the value captured by the local population from these goods and services. This paper gives some background to economic valuation (Total Economic Value, Cost Benefit Analysis) and market creation as well as three case studies. These case studies illustrate: (i) the economic valuation of marine protected areas; (ii) the economic valuation of a threat to coral reefs (coral mining); and (iii) the creation of a market for sustainably caught/reared reef fish as an alternative to cyanide fishing.
Because of their ability to transform atmospheric N2 into ammonia that can be used by the plant, researchers were originally very optimistic about the potential of associative diazotrophic bacteria to promote the growth of many cereals and grasses. However, multiple inoculation experiments during recent decades failed to show a substantial contribution of Biological Nitrogen Fixation (BNF) to plant growth in most cases. It is now clear that associative diazotrophs exert their positive effects on plant growth directly or indirectly through (a combination of) different mechanisms. Apart from fixing N2, diazotrophs can affect plant growth directly by the synthesis of phytohormones and vitamins, inhibition of plant ethylene synthesis, improved nutrient uptake, enhanced stress resistance, solubilization of inorganic phosphate and mineralization of organic phosphate. Indirectly, diazotrophs are able to decrease or prevent the deleterious effects of pathogenic microorganisms, mostly through the synthesis of antibiotics and/or fungicidal compounds, through competition for nutrients (for instance, by siderophore production) or by the induction of systemic resistance to pathogens. In addition, they can affect the plant indirectly by interacting with other beneficial microorganisms, for example, Azospirillum increasing nodulation of legumes by rhizobia. The further elucidation of the different mechanisms involved will help to make associative diazotrophs a valuable partner in future agriculture.
Many reef coral diseases have been described affecting corals in the wild, several of which have been associated with causal
agents based on experimental inoculation and testing of Koch’s postulates. In the aquarium industry, many coral diseases and
pathologies are known from the grey literature but as yet these have not been systematically described and the relationship to
known diseases in the wild is difficult to determine. There is therefore scope to aid the maintenance and husbandry of corals in
aquaria by informing the field of the scientifically described wild diseases, if these can be reliably related. Conversely, since the
main driver to identifying coral diseases in aquaria is to select an effective treatment, the lessons learnt by aquarists on which
treatments work with particular syndromes provides invaluable evidence for determining the causal agents. Such treatments
are not commonly sought by scientists working in the natural environment due the cost and potential environmental impacts
of the treatments. Here we review both wild and aquarium diseases and attempt to relate the two. Many important aquarium
diseases could not be reconciled to those in the wild. In one case, however, namely that of the ciliate Helicostoma sp. as a
causal agent of brown jelly syndrome in aquarium corals, there may be similarities with pathogenic agents of the wild
coral diseases, such as white syndrome and brown band syndrome. We propose that Helicostoma is actually a misnomer,
but improved understanding of this pathogen and others could benefit both fields. Improved practices in aquarium maintenance
and husbandry would also benefit natural environments by reducing the scale of wild harvest and improving the potential
for coral culture, both for the aquarium industry and for rehabilitation programmes.
Chytridiomycosis is an emerging infectious disease of amphibians caused by the chytrid Batrachochytrium dendrobatidis. The disease has been associated with global amphibian declines and species extinctions, however the principle drivers that underly the emergence of chytridiomycosis remain unclear. Current evidence suggests that the world trade in amphibians is implicated in the emergence of chytridiomycosis. Here, we review the evidence that the amphibian trade is driving the emergence of chytridiomycosis by (1) spreading infected animals worldwide, (2) introducing non-native infected animals into naïve populations and (3) amplifying infection of amphibians by co-housing, followed by untreated discharge of infectious zoospores into water supplies. We conclude that the evidence that the amphibian trade is contributing to the spread of Batrachochytrium dendrobatidis is strong, and that specific actions are necessary to prevent the introduction of the pathogen into thus-far uninfected areas. Specifically, we recommend the development of national risk-abatement plans, focused on firstly preventing introduction of Bd into disease free areas, and secondly, decreasing the impact of the disease on populations that are currently infected.
Marine protected areas (MPAs) have been widely adopted as the leading tool for coral-reef conservation, but resource users seldom accept them , and many have failed to produce tangible conservation benefits [3]. Few studies have objectively and simultaneously examined the types of MPAs that are most effective in conserving reef resources and the socioeconomic factors responsible for effective conservation [4-6]. We simultaneously explored measures of reef and socioeconomic conservation success at four national parks, four comanaged reserves, and three traditionally managed areas in Indonesia and Papua New Guinea. Underwater visual censuses of key ecological indicators [7, 8] revealed that the average size and biomass of fishes were higher in all areas under traditional management and at one comanaged reserve when compared to nearby unmanaged areas. Socioeconomic assessments [6, 9, 10] revealed that this "effective conservation" was positively related to compliance, visibility of the reserve, and length of time the management had been in place but negatively related to market integration, wealth, and village population size. We suggest that in cases where the resources for enforcement are lacking, management regimes that are designed to meet community goals can achieve greater compliance and subsequent conservation success than regimes designed primarily for biodiversity conservation.
Contrasting Patterns of Coral Bleaching Susceptibility
- J R Guest
- A H Baird
- J A Maynard
- E Muttaqin
- A J Edwards
- S J Campbell
- K Yewdall
- Y A Affendi
- L M Chou
Guest, J. R., A. H. Baird, J. A. Maynard, E. Muttaqin,
A. J. Edwards, S. J. Campbell, K. Yewdall, Y. A. Affendi, and
L. M. Chou. 2012. "Contrasting Patterns of Coral Bleaching
Susceptibility in 2010 Suggest an Adaptive Response to
Thermal Stress. " PLoS ONE 7: e33353.
https://coralreefwatch. noaa.gov/satellite/analyses_guidance/global_coral_ bleaching_2014-17_statusBuilding Coral Reef Resilience through Assisted Evolution
- Noaa Coral
- Reef Watch
- J K Oliver
- H M Putnam
- R D Gates
NOAA Coral Reef Watch. 2017. https://coralreefwatch.
noaa.gov/satellite/analyses_guidance/global_coral_
bleaching_2014-17_status.php
van Oppen, M. J. H., J. K. Oliver, H. M. Putnam, and R. D.
Gates. 2015. "Building Coral Reef Resilience through
Assisted Evolution. " Proc Natl Acad Sci 112: 1-7.