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Climate change, and in particular the unprecedented rapid global warming, presents a major threat to corals, with warming rates potentially exceeding the adaptive capacities of most coral species. Assisted gene flow, the human facilitated introduction of temperature resilience alleles from warmer to threatened colder populations via the movement of individuals (assisted migration) or their gametes (selective breeding), has been suggested as a tool to transfer thermal adaptations among populations. Due to its strong latitudinal temperature gradient and extreme temperature conditions, the Red Sea constitutes an ideal location to investigate the potential of this strategy. Here, we relocated Porites lobata colonies from three reefs along the Saudi Arabian Red Sea with different mean sea surface temperature summer maxima (ranging from 30.9 °C in Duba, 32.5 °C in Thuwal, to 33.8 °C in Jazan) to a common garden experiment in the intermediate central location. Five colonies from each location were fragmented and deployed in situ in early summer of 2018 to investigate physiological differences in bleaching, survival, and growth. Results showed significantly higher bleaching in fragments from Duba, followed by 65% mortality. Even though no bleaching was observed in fragments from Jazan, mortality rates of around 20% indicated that other environmental parameters besides temperature might influence coral health and survival. These results suggest that assisted gene flow via translocation alone may be restricted in its success due to a lack of local adaptations to environmental conditions other than temperature. However, strategies like inter-populational breeding may overcome these limitations as they might allow producing offspring with both increased thermal tolerance and local adaptations.

Introduction: Coral reefs worldwide decline has prompted coral restoration as a viable strategy to rewild vulnerable, foundational coral species. Stony corals are now propagated by thousands in both in-water and ex situ (land-based) coral nurseries, the latter being unexplored in Costa Rica, despite their potential benefits as a reef management tool. Objective: To analyze the viability of ex situ culturing of the Pacific reef-building corals Porites lobata and Pocillopora damicornis at Parque Marino del Pacífico (PMP), Puntarenas, Costa Rica, aquaculture facilities. Methods: From May to October 2018 a total of 180 coral fragments were kept in an aquaculture recirculated system. Survival, growth, and fragment yield in relation to culture medium (physicochemical parameters) were recorded. Results: Survival and growth rate varied between species and culture tanks. On average, surviving P. lobata fragments (68.89 %) placed in Tank 1 (T1) grew 216 %, while fragments placed in Tank 2 (T2) had a survival rate of 71.11 % and an increase of 277 % in live tissue area. P. damicornis fragments survival, basal and crown area percentage increase were: 71.11 %, 980 % and 366 % in T1, and 100 %, 976 % and 287 % in T2. Although fragments survival and growth were net positive, the yield in terms of culture was low, due to culture conditions in the tanks not meeting coral culture optimal requirements. Conclusions: Survival and growth of both species varied depending on the tank in which they were placed. Survival was similar to that found in other ex situ studies and growth was similar to those reported in the wild, however culture performance in terms of yield was low. Aquaculture systems at PMP constitute a good base for the cultivation of corals, however for the culture effort to achieve maximum yield, current systems must be optimized according to the requirements of the target coral species. [ABSTRACT FROM AUTHOR]

Coral reefs worldwide are threatened by thermally induced bleaching. In 2015, the National Oceanic and Atmospheric Administration declared the third recorded global thermal bleaching event during which Hawaiian coral reefs were severely impacted. In order to understand how Hawaiian reefs responded to this event, data were examined from benthic imagery from three sites on leeward Maui that represent a gradient of management. Data were extracted from composite 100m2 photomosaic images of reef benthos, which were constructed for July 2014 (prior to bleaching) and June 2016 (following bleaching). In each photomosaic, colonies of mounding Porites (P. lobata, P. evermanni, and P. lutea) were individually outlined and numbered in order to compare colony size class distribution before and after the 2015 bleaching event. Overall, the mounding Porites communities of leeward Maui reefs experienced a shift towards smaller size classes from 2014 to 2016. Changes in size, quantified in both absolute and percent changes, were not correlated with management regimes. These data suggest that management of local stressors may not be sufficient to mitigate the immediate effects of thermal bleaching events on coral reefs.

The relationship between thermal stress and coral bleaching has been a topic of study for decades, yet there is still a mismatch between remotely sensed bleaching predictors and population-specific bleaching responses. Recent studies have linked greater amounts of thermal variability to coral bleaching resistance over small spatial scales, yet in some sites, this variability appears to push corals beyond their thermal limits. Here, we performed a 12-month reciprocal transplant and acute heat stress experiments in populations of Porites lobata from an American Sāmoan backreef: the Highly Variable (HV), the Moderately Variable, and the Less Variable pools of Ofu to investigate how natural and experimental stress across different thermal environments related to coral bleaching responses during the 2016–2017 thermal anomaly. We also compared various sea surface satellite versus in situ temperature data to determine which metrics were most aligned with observed bleaching responses. We found ~ 0.6 °C higher maximum monthly means for in situ versus remotely sensed data, which resulted in fewer degree heating weeks. Although greater thermal variability and heat loading did not have a strong relationship with the onset of natural bleaching responses, acute heat stress revealed differences in sublethal stress responses that aligned with in situ thermal metrics. We suggest greater thermal spikes and heat loading in the HV pool, detected only in the high-resolution in situ data, best explain the decreased thermal performance seen in HV corals; demonstrating the utility of in situ data (both environmental and experimental) for understanding bleaching responses at population-specific spatial scales (< 5 km). [ABSTRACT FROM AUTHOR]

The global decline of coral reefs has driven considerable interest in active coral restoration. Despite their importance and dominance on mature reefs, relatively few coral restoration projects use slower growth forms like massive and encrusting coral species. Micro-fragmentation can increase coral cover by orders of magnitude faster than natural growth, which now allows cultivation of slow growing massive forms and shows promise and flexibility for active reef restoration. However, the major causes of variation in growth and survival of outplanted colonies remain poorly understood. Here, we report simple outplanting assays to aid in active reef restoration of slower growing species and increase the likelihood of restoration success. We used two different micro-fragmentation assays. Pyramid assays were used to examine variation associated with fragment size (ranging from ≈1-9 cm2), nursery residence time (for both in-situ and ex-situ nurseries), and 2D vs. 3D measurements of growth. Block assays were used to examine spatial variation among individual performance at outplanting sites in the field. We found 2D and 3D measurements correlated well, so measured survivorship and growth using top-down planar images for two of the main Hawaiian reef building corals, the plating Montipora capitata and the massive Porites compressa. Pyramid assays housed and outplanted from the in-situ nursery showed no effect of residence time or size on overall survivorship or growth for either species. Results from the ex-situ nursery, however, varied by species, with P. compressa again showing no effect of nursery residence time or size on survivorship or growth. In contrast, nursery culture resulted in improved survivorship of small M. capitata fragments, but net growth showed a weak positive effect of nursery time for medium fragments. Small fragments still suffered higher mortality than either medium or large fragments. Due to their lower mortality, medium fragments (≈3 cm2) appear to be the best compromise between growth and survivorship for outplanting. Likewise, given weak positive gains relative to the investment, our results suggest that it could be more cost-effective to simply outplant medium fragments as soon as possible, without intermediate culture in a nursery. Furthermore, the block assay revealed significant differences in survivorship and growth among sites for individuals of both species, emphasizing the importance of considering spatial variation in coral survival and growth following outplanting. These results highlight the value of using short-term micro-fragmentation assays prior to outplanting to assess size, and location specific performance, optimizing the efficiency of active reef restoration activities and maximizing the probability of success for active coral restoration projects. [ABSTRACT FROM AUTHOR]

The global decline of coral reefs has driven considerable interest in active coral restoration. Despite their importance and dominance on mature reefs, relatively few coral restoration projects use slower growth forms like massive and encrusting coral species. Micro-fragmentation can increase coral cover by orders of magnitude faster than natural growth, which now allows cultivation of slow growing massive forms and shows promise and flexibility for active reef restoration. However, the major causes of variation in growth and survival of outplanted colonies remain poorly understood. Here, we report simple outplanting assays to aid in active reef restoration of slower growing species and increase the likelihood of restoration success. We used two different micro-fragmentation assays. Pyramid assays were used to examine variation associated with fragment size (ranging from ≈1–9 cm2), nursery residence time (for both in-situ and ex-situ nurseries), and 2D vs. 3D measurements of growth. Block assays were used to examine spatial variation among individual performance at outplanting sites in the field. We found 2D and 3D measurements correlated well, so measured survivorship and growth using top-down planar images for two of the main Hawaiian reef building corals, the plating Montipora capitata and the massive Porites compressa. Pyramid assays housed and outplanted from the in-situ nursery showed no effect of residence time or size on overall survivorship or growth for either species. Results from the ex-situ nursery, however, varied by species, with P. compressa again showing no effect of nursery residence time or size on survivorship or growth. In contrast, nursery culture resulted in improved survivorship of small M. capitata fragments, but net growth showed a weak positive effect of nursery time for medium fragments. Small fragments still suffered higher mortality than either medium or large fragments. Due to their lower mortality, medium fragments (≈3 cm2) appear to be the best compromise between growth and survivorship for outplanting. Likewise, given weak positive gains relative to the investment, our results suggest that it could be more cost-effective to simply outplant medium fragments as soon as possible, without intermediate culture in a nursery. Furthermore, the block assay revealed significant differences in survivorship and growth among sites for individuals of both species, emphasizing the importance of considering spatial variation in coral survival and growth following outplanting. These results highlight the value of using short-term micro-fragmentation assays prior to outplanting to assess size, and location specific performance, optimizing the efficiency of active reef restoration activities and maximizing the probability of success for active coral restoration projects.

Endolithic microbes in coral reefs may act as a nutrient source for their coral hosts. Increasing atmospheric CO2 concentrations are causing ocean acidification (OA), which may affect marine organisms and ecosystems, especially calcifying organisms such as reef-building corals. However, knowledge of how OA affects marine microbes remains limited, and little research has been done on how coral endolithic communities respond to shifting environmental baselines. In this study, the endolithic communities of two common shallow water coral species, Isopora palifera and Porites lobata, were examined to investigate the microbial community dynamics under OA treatments. The colonies were placed in an environment with a partial pressure of carbon dioxide (pCO2) of 1,000 or 400 ppm (control) for 2 months. Several I. palifera colonies bleached and died at 1,000 ppm pCO2, but the P. lobata colonies remained unaffected. Inversely, the endolithic community in P. lobata skeletons showed significant changes after OA treatment, whereas no significant dynamics were observed among the I. palifera endoliths. Our findings suggest that the skeletal structures of different coral species may play a key role in corals host and endoliths under future high-OA scenarios.

The mechanisms resulting in the breakdown of the coral symbiosis once the process of bleaching has been initiated remain unclear. Distinguishing the process of symbiont loss from the thermal stress response may shed light on the cellular and molecular pathways involved in each process. This study examined physiological changes and global gene expression patterns associated with white patch syndrome (WPS) in Porites lobata, which manifests in localized bleaching independent of thermal stress. In addition, a meta‐analysis of global gene expression studies in other corals and anemones was used to contrast differential regulation as a result of disease and thermal stress from patterns correlated with symbiotic state. Symbiont density, chlorophyll a content, holobiont productivity, instant calcification rate, and total host protein content were uniformly reduced in WPS relative to healthy tissue. While expression patterns associated with WPS were secondary to fixed effects of source colony, specific functional enrichments combined with a lack of immune regulation suggest that the viral infection putatively giving rise to this condition affects symbiont rather than host cells. Expression in response to WPS also clustered independently of patterns in white syndrome impacted A. hyacinthus, further supporting a distinct aetiology of this syndrome. Expression patterns in WPS‐affected tissues were significantly correlated with prior studies that examined short‐term thermal stress responses independent of symbiotic state, suggesting that the majority of expression changes reflect a nonspecific stress response. Across studies, the magnitude and direction of expression change among particular functional enrichments suggests unique responses to stressor duration and highlights distinct responses to bleaching in an anemone model. [ABSTRACT FROM AUTHOR]

Coral bleaching events are increasing in frequency and severity, resulting in widespread losses in coral cover. However, branching corals native to highly variable (HV) thermal environments can have higher bleaching resistance than corals from more moderate habitats. Here, we investigated the response of two massive corals, Porites lobata and Goniastrea retiformis, from a moderately variable (MV) and a low variability (LV) pool transplanted into a HV pool on Ofu Island in American Samoa. Paired transplant and native ramets were exposed to an acute thermal stress after 6 and 12 months of exposure to the HV pool to evaluate changes in thermal tolerance limits. For both species, photosynthetic efficiency and chlorophyll loss following acute heat stress did not differ between ramets transplanted into the HV pool and respective native pool. Moreover, HV native P. lobata exhibited the greatest bleaching susceptibility compared to MV and LV natives and there was no effect of acute heat stress on MV P. lobata. There was also a thermal anomaly during the study, where Ofu's backreef thermal regime surpassed historical records--2015 had 8 degree heating weeks (DHW) and 2016 had up to 5 DHW (in comparison to less than or equal to 3 over the last 10 years)-- which may have exceeded the upper thermal limits of HV native P. lobata. These results strongly contrast with other research on coral tolerance in variable environments, potentially underscoring species-specific mechanisms and regional thermal anomalies that may be equally important in shaping coral responses to extreme temperatures. [ABSTRACT FROM AUTHOR]

Chronic disturbance can disrupt ecological interactions including the foundational symbiosis between reef-building corals and the dinoflagellate family Symbiodiniaceae. Symbiodiniaceae are photosynthetic endosymbionts necessary for coral survival, but many Symbiodiniaceae can also be found free-living in the environment. Since most coral species acquire new Symbiodiniaceae from the environment each generation, free-living Symbiodiniaceae represent important pools for coral symbiont acquisition. Yet, little is known about the diversity of, or impacts of disturbance on, free-living Symbiodiniaceae. To determine how chronic and pulse disturbances influence Symbiodiniaceae communities, we sampled three reef habitat compartments - sediment, water, and coral (Pocillopora grandis, Montipora aequituberculata, Porites lobata) - at sites exposed to different levels of chronic anthropogenic disturbance, before, during, and after a major storm. Almost no (4%) Symbiodiniaceae amplicon sequence variants (ASVs) were found in all three compartments, and over half were found uniquely in coral. Sites experiencing chronic disturbance were typically associated with higher symbiont beta diversity (i.e., variability and turnover) across reef habitat compartments. Pulse stress, from the storm, exhibited some influence on symbiont beta diversity but the effect was inconsistent. This suggests that in this ecosystem, the effects of chronic disturbance are more prominent than temporal variability during a pulse disturbance for shaping symbiont communities. [ABSTRACT FROM AUTHOR]

Members of the anthozoan green fluorescent protein (GFP) family display a diversity of photo-physical properties that can be associated with normal and damaged coral tissues. Poritid coral species often exhibit localized pink pigmentation in diseased or damaged tissues. Our spectral and histological analyses of pink-pigmented Porites lobata lesions show co-localization of bright red fluorescence with putative amoebocytes concentrating in the epidermis, suggesting an activated innate immune response. Here we report the cloning, expression, and characterization of a novel red fluorescent protein (plobRFP) from the pink-pigmented tissues associated with lesions on Porites lobata. In vitro, the recombinant plobRFP exhibits a distinct red emission signal of 614 nm (excitation maximum: 578 nm), making plobRFP the furthest red-shifted natural fluorescent protein isolated from a scleractinian coral. The recombinant protein has a high molar extinction coefficient (84,000 M−1 cm−1) and quantum yield (0.74), conferring a notable brightness to plobRFP. Sequence analysis suggests the distinct brightness and marked red shift may be inherent features of plobRFP's chromophore conformation. While plobRFP displays a tendency to aggregate, its high pH stability, photostability, and spectral properties make it a candidate for cell imaging applications and a potential template for engineering optimized RFPs. The association of plobRFP with a possible immune response furthers its potential use as a visual diagnostic and molecular biomarker for monitoring coral health. [ABSTRACT FROM AUTHOR]

Kondang Merak was lied on south of Java sea that has monitored coral reef inside. Environment condition such as load of terrestrial’s nutrient into the sea, increase of surface water temperature and tourism activities were affected on coral reef health. The massive Porites that common coral found in this location need be monitored gradually to see coral condition over time. The research was conducted on May 2015 in reef flat area of Kondang Merak. The aims of the research were to know distribution of massive Porites and oceanography condition in Kondang Merak. The highest sea surface temperature was 26,46o C in transect number 2 at station 1 (eastern part). Salinity of sea water was in normal range between 34, 42o/oo to 35,75o/oo, dissolved oxygen was on range 6 mg/l sampai 9,1 mg/l and pH was 7,23 sampai 8,68 respectively. Two species on massive Porites they were Porites lobata dan P. lutea. In station 1 the average diameter of P. lobata was 228.57 cm and P. lutea 63.89 cm, in while P. lobata in station 2 was 260.57 cm and P. lutea 153.56 cm.

Spatial heterogeneity in environmental characteristics can drive adaptive differentiation when contrasting environments exert divergent selection pressures. This environmental and genetic heterogeneity can substantially influence population and community resilience to disturbance events. Here, we investigated corals from the highly variable back-reef habitats of Ofu Island in American Samoa that thrive in thermal conditions known to elicit widespread bleaching and mortality elsewhere. To investigate the relative importance of acclimation versus site of origin in shaping previously observed differences in coral tolerance limits at Ofu Island, specimens of the common Indo-Pacific coral Porites lobata from locations with differing levels of thermal variability were acclimated to low and high thermal variation in controlled common garden aquaria. Overall, there were minimal effects of the acclimation exposure. Corals native to the site with the highest level of daily variability grew fastest, regardless of acclimation treatment. When exposed to lethal thermal stress, corals native to both variable sites contained elevated levels of heat shock proteins and maintained photosynthetic performance for 1-2 days longer than corals from the stable environment. Despite being separated by <5 km, there was significant genetic differentiation among coral colonies (FST=0.206, P<0.0001; nuclear ribosomal DNA), whereas Symbiodiniaceae were all Cladocopium sp. (ITS type C15). Our study demonstrates consistent signatures of adaptation in growth and stress resistance in corals from naturally thermally variable habitats, suggesting that differences in the amount of thermal variability may be an important contributor to adaptive differentiation in reef-building corals. [ABSTRACT FROM AUTHOR]

Abstract: Submarine groundwater discharge (SGD) is an important source of nutrients to many coastal reefs, yet there is little information on how SGD impacts key coral reef processes. Here, we investigated the effect of SGD on coral growth and bioerosion rates from Porites lobata nubbins and blocks of calcium carbonate (CaCO3) on two reef flats in Maunalua Bay, O'ahu. Over a 6‐month (coral nubbins) and yearlong (CaCO3 blocks) deployment period, we combined multiple metrics of coral growth (buoyant weight, surface area, and linear extension) and bioerosion with a suite of co‐measured physicochemical parameters that are indicators for SGD (carbonate chemistry, dissolved inorganic nutrients, temperature, salinity, and water motion). All coral growth metrics showed a modal response to SGD, and the percent change in buoyant weights and nubbin surface area were negatively related to pH variation. SGD negatively affected coral survival, indicating that at high levels of SGD, salinity stress could be killing corals, but at mid‐levels SGD‐associated nutrients could be increasing growth rates. SGD had a positive effect on bioerosion, most likely due to the positive effect of increased nutrients on bioeroding organisms. Further, coral accretion rates were two orders of magnitude higher than bioerosion rates; however, given the low coral cover on these reef flats, the total carbonate accreted by corals is much lower than suggested by rates alone. These results indicate that corals can thrive on SGD‐impacted reefs if isolated from secondary stressors, so active management to reduce macroalgae and sedimentation could allow coral recovery in Maunalua Bay. [ABSTRACT FROM AUTHOR]

Due to their high morphological plasticity and complex evolutionary history, the species boundaries of many reef-building corals are poorly understood. The skeletal structures of corals have traditionally been used for species identification, but these structures can be highly variable, and currently we lack knowledge regarding the extent of morphological variation within species. Porites species are notorious for their taxonomic difficulties, both morphologically and genetically, and currently there are several unresolved species complexes in the Pacific. Despite its ubiquitous presence and broad use in coral research, Porites lobata belongs to one such unresolved species complex. To understand the degree of intraspecific variation in skeletal morphology, 120 corallites from the Hawaiian P. lobata were examined. A subset of samples from two genetically differentiated populations from contrasting high- and low-stress environments in Maunalua Bay, Hawaii, were then quantitatively analyzed using multivariate morphometrics. Our observations revealed high intraspecific variation in corallite morphology, as well as significant morphological differences between the two populations of P. lobata. Additionally, significant correlation was found between the morphological and genetic distances calculated from approximately 18,000 loci generated from restriction site-associated DNA sequencing. The unique morphological characters observed from the genetically differentiated population under environmental stress suggest that these characters may have adaptive values, but how such traits relate to fitness and how much plasticity they can exhibit remain to be determined by future studies. Relatively simple morphometric analyses used in our study can be useful in clarifying the existing ambiguity in skeletal architecture, thus contributing to resolving species issues in corals. [ABSTRACT FROM AUTHOR]

Major gaps remain in our understanding of the ecology, evolution, biodiversity, biogeography, extinction risk, and adaptive potential of reef building corals. One of the central challenges remains that there are few informative genetic markers for studying boundaries between species, and variation within species. Reduced representation sequencing approaches, such as RADseq (Restriction site Associated DNA sequencing) have great potential for resolving such relationships. However, it is necessary to identify loci in order to make inferences for endosymbiotic organisms such as corals. Here, we examined twenty-one coral holobiont ezRAD libraries from Hawaiʻi, focusing on P. lobata and P. compressa , two species with contrasting morphology and habitat preference that previous studies have not resolved. We used a combination of de novo assembly and reference mapping approaches to identify and compare loci: we used reference mapping to extract and compare nearly complete mitochondrial genomes, ribosomal arrays, and histone genes. We used de novo clustering and phylogenomic methods to compare the complete holobiont data set with coral and symbiont subsets that map to transcriptomic data. In addition, we used reference assemblies to examine genetic structure from SNPs (Single Nucleotide Polymorphisms). All approaches resolved outgroup taxa but failed to resolve P. lobata and P. compressa as distinct, with mito-nuclear discordance and shared mitochondrial haplotypes within the species complex. The holobiont and ‘coral transcriptomic’ datasets were highly concordant, revealing stronger genetic structure between sites than between coral morphospecies. These results suggest that either branching morphology is a polymorphic trait, or that these species frequently hybridize. This study provides examples of several approaches to acquire, identify, and compare loci across metagenomic samples such as the coral holobiont while providing insights into the nature of coral variability. [ABSTRACT FROM AUTHOR]

Coral recruitment and juvenile growth are essential processes for coral population maintenance and recovery. A growing body of research has evaluated the influence of reef microstructure on coral settlement and post-settlement survival, showing that physical refugia enhance recruitment. These studies have evaluated coral recruit morality from competition with macroalgae and indirect predation by grazing organisms, but the impact of direct predation by corallivorous piscine species on juvenile corals and how this interacts with reef microstructure is relatively unknown. This study examined whether refugia provided by micro-crevices enhance juvenile coral survival from corallivory. Juvenile corals from two different functional groups, the slow-growing massive Porites lobata and fast-growing branching Pocillopora damicornis, with average nubbin sizes of 1.4 cm × 0.3 cm and 0.5 cm × 1.0 cm (diameter × height), respectively, were attached to experimental tiles using small (1.44 cm) and large (8.0 cm) crevice sizes and were monitored for 29 d on a forereef in Palau. Full crevices (four sided) enhanced coral survival compared to exposed microhabitats in both coral taxa, but crevice size did not alter survival rates. Corallivores targeted recruits within crevices regardless of crevice size; dominant predators included small triggerfish (Balistidae), butterflyfish ( Chaetodon), and wrasse ( Cheilinus). Overall, Pocillopora suffered much higher rates of mortality than Porites. All Pocillopora were consumed by day 8 of the experiment, but mortality was significantly delayed in full crevices compared to exposed and partial crevice (three sided) microhabitats. In contrast, Por. lobata located in all microhabitats survived the entire experiment up to 29 d, with high survival in full (>90%) and partial crevices (70%), but only 28% survival in exposed microhabitats. These findings show the importance of crevices as spatial refugia from predators for juvenile corals and highlight the importance of structural complexity for juvenile coral growth and survival that enhances reef recovery. [ABSTRACT FROM AUTHOR]

The isolated Isla del Coco experiences periodic, extreme disturbances which devastate coral reefs surrounding the island. Scleractinian corals build the physical structure of the reef therefore ecosystem recovery relies on coral species recovery. Coral recruits can be of sexual or asexual origin, and the relative success of the two recruit types influences the speed and spread of recovery processes. Here we focus on the massive coral, Porites lobata, because it is the main reef-builder around Isla del Coco to describe the relative contribution of asexual and sexual recruits to population maintenance. P. lobata samples were collected using a spatially explicit random sampling design in three plots at Isla del Coco: Punta Ulloa (n=17), Bahía Weston (n=20) and Punta María (n=20) and samples were genotyped with 11 microsatellite markers. Additional sampling was conducted at three “coastal” sites near the Costa Rican mainland (Isla del Caño Biological Reserve): Caño1 (n=8), Caño2 (n=10), Caño5 (n=11) to compare the contributions of asexual and sexual recruits at Isla del Coco sites to coastal sites. Isla del Coco sites were characterized by small colony size (>60% of colonies

Fusion is an important life history strategy for clonal organisms to increase access to shared resources, to compete for space, and to recover from disturbance. For reef building corals, fragmentation and colony fusion are key components of resilience to disturbance. Observations of small fragments spreading tissue and fusing over artificial substrates prompted experiments aimed at further characterizing Atlantic and Pacific corals under various conditions. Small (∼1–3 cm2) fragments from the same colony spaced regularly over ceramic tiles resulted in spreading at rapid rates (e.g., tens of square centimeters per month) followed by isogenic fusion. Using this strategy, we demonstrate growth, in terms of area encrusted and covered by living tissue, of Orbicella faveolata, Pseudodiploria clivosa, and Porites lobata as high as 63, 48, and 23 cm2 per month respectively. We found a relationship between starting and ending size of fragments, with larger fragments growing at a faster rate. Porites lobata showed significant tank effects on rates of tissue spreading indicating sensitivity to biotic and abiotic factors. The tendency of small coral fragments to encrust and fuse over a variety of surfaces can be exploited for a variety of applications such as coral cultivation, assays for coral growth, and reef restoration.

Artificial transplantation of corals is a common method used to restore damaged or unhealthy coral assemblages. Though a number of studies have successfully transplanted coral fragments, there is no general consensus on the type of substratum to be used. The present study focused on the growth and survivorship of Montipora capitata (rice coral) and Porites lobata (lobe coral) fragments, which were transplanted onto different natural and synthetic substrata. No significant differences in coenosarc tissue growth or survivorship were observed between the species. Measurements after 184 days of growth, found transplant growth to be significantly higher on rhyolite breccia and amorphous coral skeletons than on black ʻAʻā lava. Nevertheless, no significant differences were observed between any of the other substrata. After 365 days of growth, survivorship was also observed to not be significantly different between substrata; with the only exception of being lower on glass substratum. It is hypothesized that success in a coral reef restoration project is largely determined by the actual coral fragmentation and transplantation process; as no distinct substratum affinity was observed for M. capitata and P. lobata transplants. [ABSTRACT FROM AUTHOR]

Hermatypic corals are an important sessile group in the benthic structure of tropical coral reef communities. Many organisms, in response to the environmental conditions, have developed different strategies of growth by modifying their morphologies and reproduction mode, as is the case of free-living colonies called coralliths. So far, important parameters such as calcification, growth rates and their relation with biotic and abiotic factors on coralliths have not been described. This study represents the first record of a corallith form of Porites lobata and provides information on its sclerochronology. Coral growth parameters of different coralliths were compared by measuring extension rate (cm y − 1 ), skeletal density (g cm − 3 ), calcification rate (g cm − 2 y − 1 ), average age (yr) and sphericity (S). The influence of the environment on corallith growth was assessed using water temperature as an abiotic factor and bioturbation by fish as a biotic factor. Analysis of annual density bands using X-ray densitometry provided a mean extension rate of 0.47 ± 0.23 cm y − 1 , skeletal density of 1.08 ± 0.14 g cm − 3 , and calcification rate of 0.51 ± 0.26 g cm − 2 y − 1 . The results reveal differences in growth parameters between coralliths including a strong relationship of calcification rate with seawater temperature. In addition, direct and indirect bioturbations promoted the colony rotation resulting in a hemispherical form. Hence, the evidence suggests that scleractinian corals have developed an important growth strategy that allows the species to form new colonies and maintain successful coral reef communities through free-living corallith growth. [ABSTRACT FROM AUTHOR]

Sewage pollution threatens the health of coastal populations and ecosystems, including coral reefs. We investigated spatial patterns of sewage pollution in Puako, Hawaii using enterococci concentrations and δ 15 N Ulva fasciata macroalgal bioassays to assess relationships with the coral disease Porites lobata growth anomalies (PGAs). PGA severity and enterococci concentrations were high, spatially variable, and positively related. Bioassay algal δ 15 N showed low sewage pollution at the reef edge while high values of resident algae indicated sewage pollution nearshore. Neither δ 15 N metric predicted PGA measures, though bioassay δ 15 N was negatively related to coral cover. Furthermore, PGA prevalence was much higher than previously recorded in Hawaii and the greater Indo-Pacific, highlighting Puako as an area of concern. Although further work is needed to resolve the relationship between sewage pollution and coral cover and disease, these results implicate sewage pollution as a contributor to diminished reef health. [ABSTRACT FROM AUTHOR]

Isla del Coco has one of the most diverse and well-conserved coral reefs in Costa Rica. These reefs have been extensively studied since the 1980's, however those studies focused mainly on coral coverage. The aim of this study is to evaluate the coral reefs of the island, not only by the coverage of the substrate but also the composition of fish, invertebrates and reef complexity. A total of 17 sites around the island were sampled in July 2013 and in February-March 2014. At each site, we evaluated three depths (4-8 m, 9-12 m and 13-16 m), where three 10m long transects were sampled. Turf algae was the predominant substrate cover with 38.18±5.58 %. The crustose calcareous algae (Order Corallinales) had a 28.12±5.85 % cover and live coral was 18.64±3.55 %, with Porites lobata as the main reef builder. A total of 18 taxa of macroinvertebrates were observed in the study sites, of which 56 % of the species were not abundant, 33 % were common, and the sea urchin Diadema mexicanum was the only dominant species. The density of lobsters of the genus Panulirus was 388±385 ind ha-1, which is the highest density reported in the Eastern Tropical Pacific. Also we observed high densities of the sea cucumber Isostichopus fuscus (550 ind ha-1), which has a high commercial value. We recorded 45 338 fish individuals, distributed in 93 species, with an average of 1.2±8.5 tn ha-1. From the total of species, 51 % were uncommon, 31 % common, 11 % predominant and 8 % occasional. The fish community at Isla del Coco is represented by a large number of carnivorous species, followed by top predators, herbivores and planktivorous species. According to the fish categories of the IUCN Red List, 16 % of species are in threatened categories and represent 25 % of the total sampled biomass. When comparing with studies carried out from 1987 to the present, the recovery in coral cover over time is evident, mainly due to: 1) a decrease in the pressure of the bioerosive action of D. mexicanum; and 2) the conservation actions that have been taken on the island. This has been translated in complex and more rugose reefs. Isla del Coco reefs are healthy, with functional and complex food webs; where species of high commercial value have large populations. The effectiveness of conservation and management activities in Isla del Coco has resulted in the recovery of the reef communities. [ABSTRACT FROM AUTHOR]

Dietary specialists tend to be less susceptible to the effects of chemical defenses produced by their prey compared to generalist predators that feed upon a broader range of prey species. While many researchers have investigated the ability of insects to detoxify dietary allelochemicals, little research has been conducted in marine ecosystems. We investigated metabolic detoxification pathways in three species of butterflyfishes: the hard coral specialist feeder, Chaetodon multicinctus , and two generalist feeders, Chaetodon auriga and Chaetodon kleinii . Each species was fed tissue homogenate of the hard coral Porites lobata or the feeding deterrent compound homarine (found in the coral extract), and the expression and catalytic activity of cytochrome P450 (CYP) 3A-like and CYP2-like enzymes were examined after one-week of treatment. The P. lobata homogenate significantly induced content and catalytic activity of CYP2-like and CYP3A-like forms, by 2–3 fold and by 3–9 fold, respectively, in C. multicinctus . Homarine caused a significant decrease of CYP2-like and CYP3A-like proteins at the high dose in C. kleinii and 60–80% mortality in that species. Homarine also induced CYP3A-like content by 3-fold and catalytic activity by 2-fold in C. auriga , while causing non-monotonic increases in CYP2-like and CYP3A-like catalytic activity in C. multicinctus . Our results indicate that dietary exposure to coral homogenates and the feeding deterrent constituent within these homogenates caused species-specific modulation of detoxification enzymes consistent with the prey selection strategies of generalist and specialist butterflyfishes. [ABSTRACT FROM AUTHOR]

In recent decades, coral reefs worldwide have undergone significant changes in response to various environmental and anthropogenic impacts. Among the numerous causes of reef degradation, coral disease is one factor that is to a large extent still poorly understood. Here, we characterize the physiology of white patch syndrome (WPS), a disease affecting poritid corals on the Great Barrier Reef. WPS manifests as small, generally discrete patches of tissue discolouration. Physiological analysis revealed that chlorophyll a content was significantly lower in lesions than in healthy tissues, while host protein content remained constant, suggesting that host tissue is not affected by WPS. This was confirmed by transmission electron microscope (TEM) examination, which showed intact host tissue within lesions. TEM also revealed that Symbiodinium cells are lost from the host gastrodermis with no apparent harm caused to the surrounding host tissue. Also present in the electron micrographs were numerous virus-like particles (VLPs), in both coral and Symbiodinium cells. Small (<50 nm diameter) icosahedral VLPs were significantly more abundant in coral tissue taken from diseased colonies, and there was an apparent, but not statistically significant, increase in abundance of filamentous VLPs in Symbiodinium cells from diseased colonies. There was no apparent increase in prokaryotic or eukaryotic microbial abundance in diseased colonies. Taken together, these results suggest that viruses infecting the coral and/or its resident Symbiodinium cells may be the causative agents of WPS. [ABSTRACT FROM AUTHOR]

El coral hermatípico Porites lobata Dana, 1846 es, una de las especies más importantes en las comunidades arrecifales de América Central, pero fue registrada en México hasta 1992, en el Archipiélago de Revillagigedo. El objetivo del presente trabajo fue el de dar a conocer la distribución geográfica y algunos aspectos de la biología de P. lobata en la costa occidental de México, a partir de observaciones de campo y datos de literatura. Esta especie se distribuye en México dentro de un segmento de costa de aproximadamente 200 km, desde Nayarit (20° N) hasta Colima (19° N), y en las Islas Revillagigedo (18° N); P. lobata no aparece en el Golfo de Califomia (23° a 30° N), o en comunidades coralnas situadas de los 17° N a los 15° N. Su distribución disjunta puede ser explicada tomando en cuenta que el emisor larval hacia el continente deben ser las Revillagigedo, utilizando la Contracorriente Norecuatorial como mecanismo de transporte y dispersión. Comparando las comunidades coralinas donde ha sido localizado, P. lobata era mucho más abundante en las Revillagigedo que en el continente. Sin embargo, los daños causados por los dedepredadores parecen ser mayores en Nayarit- Jalisco- Colima que en las islas oceánicas, quizá debido a que los peces coralívoros son poco comunes allí. La densidad poblacional de los bioerosionadores (esponjas, poliquetos, sipuncúlidos y bivalvos) fue similar y a veces mayor en las colonias de P. lobata de las Revillagigedo que en aquellas de la costa continental, lo que sugiere la posibilidad de que haya un diferencial en la productividad primaria de esas localidades.The hermatypic coral Porites lobata Dana, 1846 is one of the most important species in Central American reef communities, recorded in México only in 1992, at the Revillagigedo Archipelago. This paper describes the geographic distribution and predation pressure on P. lobata in the west coast of México, based on field observations and literature data. The species is distributed in México on a coastal section of about 200 km, from Nayarit (20° N) to Colima (19° N), and in the Revillagigedo Islands (18° N); P. lobata does not occur in the Gulf of California (23° to 30° N), or at coral communities placed from 17° N to 15° N. Its disjunct distribution can be explained considering the Revillagigedos as larval emiter to the mainland, using the Northequatorial Countercurrent as dispersal mechanism. Comparing coral communities where P. lobata is found, it was more abundant in the Revillagifedos than at the mainland. However, predator damage seems to be greater in Nayarit-Jalisco-Colima than in the oceanic islands, possibly because corallivore fishes were less abundant in the latter. Population density of coral bioeroders (sponges, polychaetes, spinculans and bivalves) in P. lobata eas similar and sometimes higher at the Revillagigedos than in coastal sites, suggesting the possibility of a primary productivity diffeerential among those locations.

Sub-seasonally resolved and replicated coral Sr/Ca time series at Clipperton Atoll (10°18′N, 109°13′W) in the eastern Pacific are assessed as a sea surface temperature (SST) proxy in this region with small seasonal SST variability. The composite coral Sr/Ca time series is a partially replicated record of three live and one sub-modern colony of Porites lobata extending back to 1874. Large inter-colony coral Sr/Ca offsets equate to relative SST differences of 0.6 to 4.3 °C and limit the ability to reconstruct absolute SST changes. Moreover, the replication method revealed a 12-year section of growth in one colony where mean Sr/Ca was anomalously low (~ 1 °C higher SST) relative to the other colonies without evidence of diagenesis or other significant skeletal alterations. The presence of this anomalous interval supports the need for multi-coral Sr/Ca replication in specific sites or regions. The Clipperton Composite Sr/Ca anomaly record is significantly coherent (r = 0.71–0.76, p < 0.001) with gridded instrumental SSTs but with larger amplitude decadal variance that appears to more accurately represent actual SST variability at Clipperton. The amplitude of the secular warming trend during the last century at Clipperton is 0.3 to 0.6 °C larger (~ twice as large) than the trend in the poorly “ground-truthed” instrumental SST records for the region. The interannual and decadal variability in Clipperton coral Sr/Ca demonstrates strong coherence to the Pacific Decadal Oscillation and the El Niño/Southern Oscillation (ENSO) with reduced ENSO variability from 1920 to late 1930s and enhanced variability in the late twentieth century. [ABSTRACT FROM AUTHOR]

Abstract: Cadmium (Cd) concentrations in coral skeleton track oceanic upwelling, which brings Cd-rich deep water to the surface. In this study we report sub-monthly measurements of [Cd]coral measured via laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) in three species of coral (Porites lobata, Pavona gigantea, and Pavona clavus) from an upwelling site in the Gulf of Panama. Although single LA tracks in all species yielded variable results, the average of multiple tracks mirrored changes in in situ seawater Cd ([Cd]sw), with an offset between peaks. In addition, [Cd]coral determined by LA-ICP-MS and isotope dilution (ID)-ICP-MS was compared in P. clavus and found to be highly correlated, despite consistently lower concentrations measured using the ID method. Two 5.5-month long high-resolution P. clavus [Cd]coral records revealed that the maximum [Cd]coral values occurred after the sea surface temperature minimum, at the same time as the seawater phosphate concentration and coral P/Ca maximum, and approximately one month before peak [Cd]sw. Based on these findings we hypothesize that corals are actively taking up Cd and incorporating it into their skeleton, and that [Cd]sw only increases once Cd is no longer being rapidly removed from the water column via biological processes. After accounting for a 1-month offset between the coral and seawater [Cd] maxima, both LA- and ID-derived [Cd]coral values were significantly correlated to [Cd]sw, providing a calibration for this [Cd]sw proxy in P. clavus. A three year high-resolution P. clavus LA-[Cd]coral record demonstrated the potential of [Cd]coral to generate a high-resolution [Cd]sw record. However, due to the natural variability in high-resolution LA-ICPMS [Cd]coral values within and among coral colonies, three laser tracks per colony and at least three colonies of P. clavus need to be analyzed to produce a reliable coral [Cd]coral record. [Copyright &y& Elsevier]

Mounding corals survive bleaching events in greater numbers than branching corals. However, no study to date has determined the underlying physiological and biogeochemical trait(s) that are responsible for mounding coral holobiont resilience to bleaching. Furthermore, the potential of dissolved organic carbon (DOC) as a source of fixed carbon to bleached corals has never been determined. Here, Porites lobata corals were experimentally bleached for 23 days and then allowed to recover for 0, 1, 5, and 11 months. At each recovery interval a suite of analyses were performed to assess their recovery (photosynthesis, respiration, chlorophyll a, energy reserves, tissue biomass, calcification, δ13C of the skeletal, δ13C, and δ15N of the animal host and endosymbiont fractions). Furthermore, at 0 months of recovery, the assimilation of photosynthetically acquired and zooplankton-feeding acquired carbon into the animal host, endosymbiont, skeleton, and coral-mediated DOC were measured via 13C-pulse-chase labeling. During the first month of recovery, energy reserves and tissue biomass in bleached corals were maintained despite reductions in chlorophyll a, photosynthesis, and the assimilation of photosynthetically fixed carbon. At the same time, P. lobata corals catabolized carbon acquired from zooplankton and seemed to take up DOC as a source of fixed carbon. All variables that were negatively affected by bleaching recovered within 5 to 11 months. Thus, bleaching resilience in the mounding coral P. lobata is driven by its ability to actively catabolize zooplankton-acquired carbon and seemingly utilize DOC as a significant fixed carbon source, facilitating the maintenance of energy reserves and tissue biomass. With the frequency and intensity of bleaching events expected to increase over the next century, coral diversity on future reefs may favor not only mounding morphologies but species like P. lobata, which have the ability to utilize heterotrophic sources of fixed carbon that minimize the impact of bleaching and promote fast recovery. [ABSTRACT FROM AUTHOR]