scholarly journals Variation in susceptibility among three Caribbean coral species and their algal symbionts indicates the threatened staghorn coral, Acropora cervicornis, is particularly susceptible to elevated nutrients and heat stress

2021 ◽  
Author(s):  
Ana M. Palacio-Castro ◽  
Caroline E. Dennison ◽  
Stephanie M. Rosales ◽  
Andrew C. Baker
Keyword(s):  
Heat Stress ◽  
Coral Species ◽  
Coral Cover ◽  
Photochemical Efficiency ◽  
Acropora Cervicornis ◽  
Nutrient Inputs ◽  
Algal Symbionts ◽  
Algal Symbiont ◽  
Orbicella Faveolata ◽  
Significant Mortality

Coral cover is declining worldwide due to multiple interacting threats. We compared the effects of elevated nutrients and temperature on three Caribbean corals: Acropora cervicornis, Orbicella faveolata, and Siderastrea siderea. Colonies hosting different algal types were exposed to either ambient nutrients (A), elevated NH4 (N), or elevated NH4 + PO4 (N+P) at control temperatures (26 °C) for > 2 months, followed by a 3-week thermal challenge (31.5 °C). A. cervicornis hosted Symbiodinium (S. fitti) and was highly susceptible to the combination of elevated nutrients and temperature. During heat stress, A. cervicornis pre-exposed to elevated nutrients experienced 84%-100% mortality and photochemical efficiency (Fv/Fm) declines of 41-50%. In comparison, no mortality and lower Fv/Fm declines (11-20%) occurred in A. cervicornis that were heat-stressed but not pre-exposed to nutrients. O. faveolata and S. siderea response to heat stress was determined by their algal symbiont community and was not affected by nutrients. O. faveolata predominantly hosted Durusdinium trenchii or Breviolum, but only corals hosting Breviolum were susceptible to heat, experiencing 100% mortality, regardless of nutrient treatment. S. siderea colonies predominantly hosted Cladocopium C1 (C. goreaui), Cladocopium C3, D. trenchii, or variable proportions of Cladocopium C1 and D. trenchii. This species was resilient to elevated nutrients and temperature, with no significant mortality in any of the treatments. However, during heat stress, S. siderea hosting Cladocopium C3 suffered higher reductions in Fv/Fm (41-56%) compared to S. siderea hosting Cladocopium C1 and D. trenchii (17-26% and 10-16%, respectively). These differences in holobiont susceptibility to elevated nutrients and heat may help explain historical declines in A. cervicornis starting decades earlier than other Caribbean corals. Our results suggest that tackling only warming temperatures may be insufficient to ensure the continued persistence of Caribbean corals, especially A. cervicornis. Reducing nutrient inputs to reefs may also be necessary for these iconic coral species to survive.

scholarly journals Tissue mortality by Caribbean ciliate infection and white band disease in three reef-building coral species

PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e2196 ◽  
Author(s):  
Alejandra Verde ◽  
Carolina Bastidas ◽  
Aldo Croquer
Keyword(s):  
Coral Species ◽  
Coral Cover ◽  
Mortality Rates ◽  
Tissue Loss ◽  
Coral Tissue ◽  
Acropora Cervicornis ◽  
White Band ◽  
Orbicella Faveolata ◽  
The Caribbean ◽  
White Band Disease

Caribbean ciliate infection (CCI) and white band disease (WBD) are diseases that affect a multitude of coral hosts and are associated with rapid rates of tissue losses, thus contributing to declining coral cover in Caribbean reefs. In this study we compared tissue mortality rates associated to CCI in three species of corals with different growth forms:Orbicella faveolata(massive-boulder),O. annularis(massive-columnar) andAcropora cervicornis(branching). We also compared mortality rates in colonies ofA. cervicornisbearing WBD and CCI. The study was conducted at two locations in Los Roques Archipelago National Park between April 2012 and March 2013. InA. cervicornis, the rate of tissue loss was similar between WBD (0.8 ± 1 mm/day, mean ± SD) and CCI (0.7 ± 0.9 mm/day). However, mortality rate by CCI inA. cervicorniswas faster than in the massive speciesO. faveolata(0.5 ± 0.6 mm/day) andO. annularis(0.3 ± 0.3 mm/day). Tissue regeneration was at least fifteen times slower than the mortality rates for both diseases regardless of coral species. This is the first study providing coral tissue mortality and regeneration rates associated to CCI in colonies with massive morphologies, and it highlights the risks of further cover losses of the three most important reef-building species in the Caribbean.

scholarly journals An algal symbiont (Breviolum psygmophilum) responds more strongly to chronic high temperatures than its facultatively symbiotic coral host (Astrangia poculata)

2021 ◽  
Author(s):  
Andrea N. Chan ◽  
Luis A. González-Guerrero ◽  
Roberto Iglesias-Prieto ◽  
Elizabeth M. Burmester ◽  
Randi D. Rotjan ◽  
...  
Keyword(s):  
Heat Stress ◽  
Thermal Stress ◽  
Stress Response ◽  
Coral Bleaching ◽  
Scleractinian Corals ◽  
Coral Host ◽  
Algal Symbionts ◽  
Algal Symbiont ◽  
Astrangia Poculata ◽  
And Control

AbstractScleractinian corals form the foundation of coral reefs by secreting skeletons of calcium carbonate. Their intracellular algal symbionts (Symbiodiniaceae) translocate a large proportion of photosynthate to the coral host, which is required to maintain high rates of calcification. Global warming is causing dissociation of coral host and algal symbiont, visibly presented as coral bleaching. Despite decades of study, the precise mechanisms of coral bleaching remain unknown. Separating the thermal stress response of the coral from the algal symbiont is key to understanding bleaching in tropical corals. The facultatively symbiotic northern star coral, Astrangia poculata, naturally occurs as both symbiotic and aposymbiotic (lacking algal symbionts) polyps – sometimes on the same coral colony. Thus, it is possible to separate the heat stress response of the coral host alone from the coral in symbiosis with its symbiont Breviolum psygmophilum. Using replicate symbiotic and aposymbiotic ramets of A. poculata, we conducted a chronic heat stress experiment to increase our understanding of the cellular mechanisms resulting in coral bleaching. Sustained high temperature stress resulted in photosynthetic dysfunction in B. psygmophilum, including a decline in maximum photosynthesis rate, maximum photochemical efficiency, and the absorbance peak of chlorophyll a. Interestingly, the metabolic rates of symbiotic and aposymbiotic corals were differentially impacted. RNAseq analysis revealed more differentially expressed genes between heat-stressed and control aposymbiotic colonies than heat-stressed and control symbiotic colonies. Notably, aposymbiotic colonies increased the expression of inflammation-associated genes such as nitric oxide synthases. Unexpectedly, the largest transcriptional response was observed between heat-stressed and control B. psygmophilum, including genes involved in photosynthesis, response to oxidative stress, and meiosis. Thus, it appears that the algal symbiont suppresses the immune response of the host, potentially increasing the vulnerability of the host to pathogens. The A. poculata-B. psygmophilum symbiosis provides a tractable model system for investigating thermal stress and immune challenge in scleractinian corals.

scholarly journals Increased Algal Symbiont Density Reduces Host Immunity in a Threatened Caribbean Coral Species, Orbicella faveolata

2020 ◽  
Vol 8 ◽  
Author(s):  
Lauren E. Fuess ◽  
Ana M. Palacio-Castro ◽  
Caleb C. Butler ◽  
Andrew C. Baker ◽  
Laura D. Mydlarz
Keyword(s):  
Coral Species ◽  
Host Immunity ◽  
Algal Symbiont ◽  
Orbicella Faveolata ◽  
Caribbean Coral

scholarly journals Metabolome shift associated with thermal stress in coral holobionts

2020 ◽  
Author(s):  
Amanda Williams ◽  
Eric N. Chiles ◽  
Dennis Conetta ◽  
Jananan S. Pathmanathan ◽  
Phillip A. Cleves ◽  
...  
Keyword(s):  
Heat Stress ◽  
Thermal Stress ◽  
Coral Species ◽  
Related Function ◽  
Montipora Capitata ◽  
Algal Symbiont ◽  
Coral Holobiont ◽  
Algal Symbiosis ◽  
Coral Health ◽  
Global Threat

SummaryCoral reef systems are under global threat due to warming and acidifying oceans1. Understanding the response of the coral holobiont to environmental change is crucial to aid conservation efforts. The most pressing problem is “coral bleaching”, usually precipitated by prolonged thermal stress that disrupts the algal symbiosis sustaining the holobiont2,3. We used metabolomics to understand how the coral holobiont metabolome responds to heat stress with the goal of identifying diagnostic markers prior to bleaching onset. We studied the heat tolerant Montipora capitata and heat sensitive Pocillopora acuta coral species from the Hawaiian reef system in Kāne’ohe Bay, O’ahu. Untargeted LC-MS analysis uncovered both known and novel metabolites that accumulate during heat stress. Among those showing the highest differential accumulation were a variety of co-regulated dipeptides present in both species. The structures of four of these compounds were determined (Arginine-Glutamine, Lysine-Glutamine, Arginine-Valine, and Arginine-Alanine). These dipeptides also showed differential accumulation in symbiotic and aposymbiotic (alga free) individuals of the sea anemone model Aiptasia4, suggesting their animal provenance and algal symbiont related function. Our results identify a suite of metabolites associated with thermal stress that can be used to diagnose coral health in wild samples.

scholarly journals Increasing coral calcification in Orbicella faveolata and Pseudodiploria strigosa at Flower Garden Banks, Gulf of Mexico

Coral Reefs ◽  
2021 ◽  
Author(s):  
Derek P. Manzello ◽  
Graham Kolodziej ◽  
Amanda Kirkland ◽  
Nicole Besemer ◽  
Ian C. Enochs
Keyword(s):  
Gulf Of Mexico ◽  
High Latitude ◽  
Coral Species ◽  
Coral Cover ◽  
Warming Trend ◽  
Coral Growth ◽  
Western Atlantic ◽  
Skeletal Density ◽  
Atchafalaya River ◽  
Orbicella Faveolata

AbstractCoral reefs are globally in decline and western Atlantic reefs have experienced the greatest losses in live coral cover of any region. The Flower Garden Banks (FGB) in the Gulf of Mexico are high-latitude, remote reefs that are an outlier to this trend, as they have maintained coral cover ≥ 50% since at least 1989. Quantifying the long-term trends in coral growth of key reef-building coral species, and the underlying environmental drivers, leads to a better understanding of local sensitivities to past changes that will ultimately allow us to better predict the future of reef growth at FGB. We obtained coral cores and constructed growth records for two of the most abundant hermatypic coral species at FGB, Pseudodiploria strigosa and Orbicella faveolata. Our records cover 57 yrs of growth for P. strigosa (1957–2013) and 45 yrs for O. faveolata (1970–2014). Linear extension and calcification rates of both species have increased significantly, but skeletal density did not change over the respective time periods. Extension and calcification data of both species combined were negatively correlated with the discharge from the Atchafalaya River, but positively correlated with maximum sea surface temperatures (SST). These data provide evidence that runoff from the Atchafalaya River impacts FGB corals and is a major control on coral growth at FGB. The increase in growth at FGB can be attributed to the significant warming trend in maximum monthly SSTs. Given the warming trend and recent increase in severity of bleaching at FGB, the prognosis is that bleaching events will become more deleterious with time, which will lead to a breakdown in the positive relationship between coral growth and maximum SST. This study provides further evidence that some high-latitude, cooler reef sites have experienced a stimulation in coral growth with ocean warming.

scholarly journals Fish predation hinders the success of coral restoration efforts using fragmented massive corals

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e9978 ◽  
Author(s):  
Gammon Koval ◽  
Nicolas Rivas ◽  
Martine D’Alessandro ◽  
Dalton Hesley ◽  
Rolando Santos ◽  
...  
Keyword(s):  
Coral Species ◽  
Coral Cover ◽  
Complete Removal ◽  
Fish Predation ◽  
Reef Restoration ◽  
Slowing Down ◽  
Early Results ◽  
Orbicella Faveolata ◽  
Propagation Technique ◽  
The Impact

As coral reefs continue to decline globally, coral restoration practitioners have explored various approaches to return coral cover and diversity to decimated reefs. While branching coral species have long been the focus of restoration efforts, the recent development of the microfragmentation coral propagation technique has made it possible to incorporate massive coral species into restoration efforts. Microfragmentation (i.e., the process of cutting large donor colonies into small fragments that grow fast) has yielded promising early results. Still, best practices for outplanting fragmented corals of massive morphologies are continuing to be developed and modified to maximize survivorship. Here, we compared outplant success among four species of massive corals (Orbicella faveolata, Montastraea cavernosa, Pseudodiploria clivosa, and P. strigosa) in Southeast Florida, US. Within the first week following coral deployment, predation impacts by fish on the small (<5 cm2) outplanted colonies resulted in both the complete removal of colonies and significant tissue damage, as evidenced by bite marks. In our study, 8–27% of fragments from four species were removed by fish within one week, with removal rates slowing down over time. Of the corals that remained after one week, over 9% showed signs of fish predation. Our findings showed that predation by corallivorous fish taxa like butterflyfishes (Chaetodontidae), parrotfishes (Scaridae), and damselfishes (Pomacentridae) is a major threat to coral outplants, and that susceptibility varied significantly among coral species and outplanting method. Moreover, we identify factors that reduce predation impacts such as: (1) using cement instead of glue to attach corals, (2) elevating fragments off the substrate, and (3) limiting the amount of skeleton exposed at the time of outplanting. These strategies are essential to maximizing the efficiency of outplanting techniques and enhancing the impact of reef restoration.

scholarly journals Host genotype and stable differences in algal symbiont communities explain patterns of thermal stress response of Montipora capitata following thermal pre-exposure and across multiple bleaching events

2020 ◽  
Author(s):  
Jenna Dilworth ◽  
Carlo Caruso ◽  
Valerie A. Kahkejian ◽  
Andrew C. Baker ◽  
Crawford Drury
Keyword(s):  
Thermal Stress ◽  
Community Composition ◽  
Photochemical Efficiency ◽  
Coral Host ◽  
Host Genotype ◽  
Reef Environment ◽  
Montipora Capitata ◽  
Algal Symbionts ◽  
Algal Symbiont ◽  
Photochemical Damage

AbstractAs sea surface temperatures increase worldwide due to climate change, coral bleaching events are becoming more frequent and severe, resulting in reef degradation. Leveraging the inherent ability of reef-building corals to acclimatize to thermal stress via pre-exposure to protective temperature treatments may become an important tool in improving the resilience of coral reefs to rapid environmental change. We investigated whether historical bleaching phenotype, coral host genotype, and exposure to protective temperature treatments would affect the response of the Hawaiian coral Montipora capitata to natural thermal stress. Fragments were collected from colonies that demonstrated different bleaching responses during the 2014-2015 event in Kāne’ohe Bay (O’ahu, Hawai’i) and exposed to four different artificial temperature pre-treatments (and a control at ambient temperature). After recovery, fragments experienced a natural thermal stress event either in laboratory conditions or their native reef environment. Response to thermal stress was quantified by measuring changes in the algal symbionts’ photochemical efficiency, community composition, and relative density. Historical bleaching phenotype was reflected in stable differences in symbiont community composition, with historically bleached corals containing only Cladocopium symbionts and historically non-bleached corals having mixed symbiont communities dominated by Durusdinium. Mixed-community corals lost more Cladocopium than Cladocopium-only corals during the natural thermal stress event, and preferentially recovered with Durusdinium. Laboratory pre-treatments exposed corals to more thermal stress than anticipated, causing photochemical damage that varied significantly by genotype. While none of the treatments had a protective effect, temperature variation during treatments had a significant detrimental effect on photochemical efficiency during the thermal stress event. These results show that acclimatization potential is affected by fine-scale differences in temperature regime, host genotype, and relatively stable differences in symbiont community composition that underpin historical bleaching phenotypes in M. capitata.

scholarly journals ENSAMBLES DE MACROALGAS SOBRE SUPERFICIES MUERTAS DE CORALES ESCLERACTINIOS (ANTHOZOA: SCLERACTINIA) EN EL ARRECIFE ORO VERDE, VERACRUZ, MÉXICO

2017 ◽  
Vol 32 (1) ◽  
pp. 11
Author(s):  
IVONNE LUNA ORTEGA ◽  
VICENCIO DE LA CRUZ FRANCISCO
Keyword(s):  
Coral Species ◽  
Taxonomic Composition ◽  
Scleractinian Corals ◽  
Porites Astreoides ◽  
Orbicella Faveolata ◽  
Ordination Analysis ◽  
Species Similarity ◽  
Filamentous Macroalgae ◽  
Algal Assemblages ◽  
Montastraea Cavernosa

Las macroalgas son abundantes en el arrecife Oro Verde, Veracruz pero, hasta ahora, se desconocía su riqueza taxonómica, y se presume que presentan asentamientos en los corales escleractinios hermatípicos. Por ello el presente trabajo investigó qué especies de corales presentaron colonizaciones algales; además, se determinó la composición taxonómica y la similitud de los ensambles de macroalgas entre las especies de corales escleractinios. Se establecieron diez puntos de muestreo de manera sistemática en el arrecife; en cada lugar de estudio se colocó un transecto de banda de 50 x 2 m para localizar y recolectar macroalgas en superficies muertas de corales escleractinios. La frecuencia de aparición de las algas se estimó con base en el total de corales estudiados, así como para cada especie coral. Para explicar similitudes y diferencias significativas de la composición de ensamblajes macroalgales entre especies de corales se aplicaron análisis de similitud y ordenación. Los corales escleractinios con ensambles de algas fueron Siderastrea siderea, Montastraea cavernosa, Pseudodiploria strigosa, Colpophylia natans, Stephanocoenia intersepta, Porites astreoides, Orbicella annularis, Orbicella faveolata. De un total de 100 colonias coralinas revisadas se determinaron 32 especies de macroalgas, las cuales están representadas en tres divisiones, 10 órdenes y 15 familias. Las macroalgas corticadas, foliosas corticadas y filamentosas fueron las más representadas en especies. Las algas de mayor frecuencia sobre los corales masivos fueron Laurencia obtusa, Amphiroa rigida y Caulerpa chemnitzia. Los corales masivos con mayor número de registros de algas fueron S. siderea (9 especies), M. cavernosa (19) y P. strigosa (17). Los ensambles algales en los corales masivos presentaron baja similitud, sin embargo no se detectaron grupos significativamente disimiles. Solamente S. siderea y M. cavernosa son ligeramente parecidos en la composición ficológica. Los resultados sugieren que los corales masivos del arrecife Oro Verde son vulnerables a la colonización de algas, pero es necesario indagar qué condiciones preceden al asentamiento algal.Macroalgal assemblages on dead surfaces of scleractinian corals (Anthozoa: Scleractinia) in the Oro Verde reef, Veracruz, MexicoBenthic macroalgae are abundant in the Oro Verde reef but their taxonomic richness was hitherto unknown and it is presumed to present settlements on the massive corals. For this reason, the present work investigated which species of massive corals show algal colonization. Also, their taxonomic composition was determined, and the similarity of the algal assemblages between species of scleractinian corals was measured. Ten sampling points were systematically established in the reef, where a transect band of 50 x 2 m at each site was placed to locate and collect algae fron the dead surfaces of scleractinian corals. The frequency of occurrence of algae species was estimated based on the total number of coral species studied, as well as on each coral species. Similarity and ordination analysis were applied in order to explain similarities and significant differences of the phycological composition among the coral species. Scleractinian corals with algal assemblages were: Siderastrea siderea, Montastraea cavernosa, Pseudodiploria strigosa, Colpophylia natans, Stephanocoenia intersepta, Porites astreoides, Orbicella annularis, Orbicella faveolata. Thirty-two species of algae were identified from a total of 100 revised coral colonies which are represented in 3 divisions, 10 orders and 15 families. The corticated, foliose corticated and filamentous macroalgae were the most represented species. The most frequent algae on massive corals were Laurencia obtusa, Amphiroa rigida and Caulerpa chemnitzia. Massive corals with higher algal records were S. siderea (9 species), M. cavernosa (19 species) and P. strigosa (17 species). The algal assemblages on the massive corals presented low similarity. However, no significant dissimilar groups were detected. Only S. siderea and M. cavernosa are relatively similar in phycological composition. The results suggest that the massive corals of the Oro Verde reef are vulnerable to the colonization of algae, but it is necessary to investigate the conditions preceding algal settlement.

scholarly journals Seascape genomics reveals candidate molecular targets of heat stress adaptation in three coral species

2020 ◽  
Author(s):  
Oliver Selmoni ◽  
Gaël Lecellier ◽  
Hélène Magalon ◽  
Laurent Vigliola ◽  
Francesca Benzoni ◽  
...  
Keyword(s):  
Heat Stress ◽  
Molecular Mechanisms ◽  
Coral Species ◽  
New Caledonia ◽  
Heat Waves ◽  
Molecular Targets ◽  
Remote Sensing Data ◽  
Stress Adaptation ◽  
Nucleotide Polymorphisms ◽  
Apoptotic Pathways

AbstractAnomalous heat waves are causing a major decline of hard corals around the world and threatening the persistence of coral reefs. There are, however, reefs that had been exposed to recurrent thermal stress over the years and whose corals appeared tolerant against heat. One of the mechanisms that could explain this phenomenon is local adaptation, but the underlying molecular mechanisms are poorly known.In this work, we applied a seascape genomics approach to study heat stress adaptation in three coral species of New Caledonia (southwestern Pacific) and to uncover molecular actors potentially involved. We used remote sensing data to characterize the environmental trends across the reef system, and sampled corals living at the most contrasted sites. These samples underwent next generation sequencing to reveal single-nucleotide-polymorphisms (SNPs) of which frequencies associated with heat stress gradients. As these SNPs might underpin an adaptive role, we characterized the functional roles of the genes located in their genomic neighborhood.In each of the studied species, we found heat stress associated SNPs notably located in proximity of genes coding for well-established actors of the cellular responses against heat. Among these, we can mention proteins involved in DNA damage-repair, protein folding, oxidative stress homeostasis, inflammatory and apoptotic pathways. In some cases, the same putative molecular targets of heat stress adaptation recurred among species.Together, these results underscore the relevance and the power of the seascape genomics approach for the discovery of adaptive traits that could allow corals to persist across wider thermal ranges.

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