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Throughout their existence, coral reefs around the world have encountered a range of challenges, both natural and human-made. Despite these hurdles, they have displayed remarkable resilience and managed to withstand the cycle of life and death. One major threat to these reefs is the pink spot disease, which causes significant harm to the diversity of reef ecosystems on a global scale. Recently, the Andaman Islands experienced the destructive consequences of this disease on three types of stony corals belonging to the Poritidae family - Porites lutea, P. lobata, and P. solida. The affected colonies suffered a decline in live reef cover ranging from 15 to 39 %. [ABSTRACT FROM AUTHOR]

The coral reef habitats have been facing insightful threats from natural and anthropogenic sources across the world; while natural threats are creating major ecological pressure with the maximum percentage of devastation to the entire ecosystems. The Acanthaster planci (L) or Crown-of-Thorns Sea star (CoTS) is known as potential natural predator of corals and can disrupt the entire reef ecosystem with their outbreaks within the much-stipulated time. CoTS are reported from all the reef areas of Andaman and Nicobar Islands with a mean density of 0.71/hectare within the range of 1.08±0.33 to 0.40±0.18 per hectare between North & Middle Andaman and Nicobar respectively. The distributional pattern of CoTS signifies that the reef crest represents maximum occurrence in comparison with reef slop and reef top; while an inversely proportional relationship can be seen between the occurrence of individuals and depth gradients. Maximum association of the CoTS is recorded with acroporidae corals while corallivorous impacts of CoTS are also recorded with poritidae corals which are not much reported across the world. No observation on the population outbreaks of CoTS was made during the decadal study period from Andaman and Nicobar Islands while the density is intrinsically noted within the limit of the natural population level of CoTS. The presence of natural predators like CoTS in Andaman and Nicobar Islands used to take a leading role in the balancing of reef ecology which denotes the healthy reef ecosystem of this archipelago. [ABSTRACT FROM AUTHOR]

As evolutionary relationships among some coral species still remain unclear, studies on unstudied area such as the Persian Gulf (PG), as part of the western Indo-Pacific, may reveal a better understanding of phylogenetic positions and relationships of corals. In the present study, the phylogenetic relationships of eight common coral species (Favites pentagona, Platygyra daedalea, Cyphastrea microphthalma, Siderastrea savignyana, Pavona decussata, Pavona cactus, Goniopora columna, and Goniopora djiboutiensis) collected from two Iranian Islands were compared with the congeneric sequences from the Indo-Pacific (IP) using rDNA region. The result shows that some coral species which were hitherto considered as representatives of widespread species from IP are related to distinct lineages. Further, it appears that morphological convergence between the taxa leads to an underestimation of the real coral species diversity in the PG. The current study is the first attempt to investigate the phylogenetic position of coral species from the PG in comparison to their counterparts from the IP. As conservation planning hinges on the identification of species, taxonomic revisions have to be undertaken in order to obtain a more reliable picture of coral species diversity in the PG. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Diversification of the Opecoelidae appears driven by intermediate host switches. • A new genus and subfamily are suggested for the only lineage of trematodes known to infect corals. • Trematodiasis in corals is likely caused by a complex of many species. • Four new opecoelid species from butterflyfishes in French Polynesia are described. Abstract Podocotyloides stenometra Pritchard, 1966 (Digenea: Opecoelidae) is the only trematode known to infect anthozoan corals. It causes disease in coral polyps of the genus Porites Link (Scleractinia: Poritidae) and its life-cycle depends on ingestion of these polyps by butterflyfishes (Perciformes: Chaetodontidae). This species has been reported throughout the Indo-Pacific, from the Seychelles to the Galápagos, but no study has investigated whether multiple species are involved. Here, we recollect P. stenometra from its type-host and type-locality, in Hawaiian waters, and describe four new species from examination of 768 butterflyfishes from French Polynesia. On the basis of morphology, phylogeny and life-history, we propose Polypipapiliotrema Martin, Cutmore & Cribb n. gen. and the Polypipapiliotrematinae Martin, Cutmore & Cribb n. subf., for P. stenometra (Pritchard) n. comb., P. citerovarium Martin, Cutmore & Cribb n. sp., P. hadrometra Martin, Cutmore & Cribb n. sp., P. heniochi Martin, Cutmore & Cribb n. sp., and P. ovatheculum Martin, Cutmore & Cribb n. sp. Given the diversity uncovered here and the ubiquity, abundance and diversity of butterflyfishes on coral reefs, we predict that Polypipapiliotrema will prove to comprise a rich complex of species causing disease in corals across the Indo-Pacific. The unique life-cycle of these taxa is consistent with phylogenetic distinction of the group and provides evidence for a broader basis of diversification among the family. We argue that life-cycle specialisation, in terms of adoption of disparate second intermediate host groups, has been a key driver of the diversification and richness of the Opecoelidae, the largest of all trematode families and the group most frequently encountered in coral reef fishes. [ABSTRACT FROM AUTHOR]

Aim Coral reefs are experiencing both an increasing frequency and intensity of anomalously warm ocean temperatures because of climate change. Studies show that the majority of coral populations will likely decline as temperatures continue to increase, although some previous species-distribution models predict that ubiquitous species, such as the primary reef-building coral species Porites lobata, will increase their distribution under projected climate change. These predictive models, however, assume that all individuals of a population are able to tolerate the entire range of environmental conditions within the species' geographic range. The effects of genetic isolation and local adaptation are not considered in species-distribution models that assume genetically contiguous populations. We aim to determine the effects of genetic isolation and local adaptation in species-distribution modelling of the ubiquitous species P. lobata under three climate change scenarios by comparing contiguous and isolated subpopulations. Location Indian and Pacific Oceans. Methods We ran a novel species-distribution model for P. lobata, segregated as five geographically isolated regions across the Indian and Pacific Oceans, and examined the species response to three climate-change scenarios (i.e., A2, A1B and B1, most recently considered as Representative Concentration Pathways 8.5, 6.0, and 4.5 Wm−2) by the year 2100. Results In contrast with previous homogeneous species-distribution models that predict a global expansion of P. lobata, ( ˜5 ± 1%), we predict major losses of suitable habitat for P. lobata in four of the five regions examined, particularly in the central Pacific Ocean (>99% ± <0.1% for all climate scenarios). Indeed, when geographic and genetic isolation were considered, our predictions suggested that P. lobata would lose between 50-52 ± 4% of its habitat, depending on the climate-change scenario, mainly in the Pacific Ocean. Main conclusions Genetic isolation will likely play a major role in the persistence of coral species under climate change, and small isolated populations may be more vulnerable to climate change than populations in large, highly connected regions. [ABSTRACT FROM AUTHOR]

Variable skeletal morphology, genotype induced plasticity, and homoplasy of skeletal structures have presented major challenges for scleractinian coral taxonomy and systematics since the 18th century. Although the recent integration of genetic and micromorphological data is helping to clarify the taxonomic confusion within the order, phylogenetic relationships and species delimitation within most coral genera are still far from settled. In the present study, the species boundaries in the scleractinian coral genus Goniopora were investigated using 199 colonies from the Saudi Arabian Red Sea and sequencing of four molecular markers: the mitochondrial intergenic spacer between CytB and NAD2, the nuclear ribosomal ITS region, and two single-copy nuclear genes (ATPsβ and CalM). DNA sequence data were analyzed using a variety of methods and exploratory species-delimitation tools. The results were broadly congruent in identifying five distinct molecular lineages within the sequenced Goniopora samples: G. somaliensis / G. savignyi , G. djiboutiensis / G. lobata , G. stokesi , G. albiconus / G. tenuidens , and G. minor / G. gracilis . Although the traditional macromorphological characters used to identify these nine morphospecies were not able to discriminate the obtained molecular clades, informative micromorphological and microstructural features (such as the micro-ornamentation and the arrangement of the columella) were recovered among the five lineages. Moreover, unique in vivo morphologies were associated with the genetic-delimited lineages, further supporting the molecular findings. This study represents the first attempt to identify species boundaries within Goniopora using a combined morpho-molecular approach. The obtained data establish a basis for future taxonomic revision of the genus, which should include colonies across its entire geographical distribution in the Indo-Pacific. [ABSTRACT FROM AUTHOR]

Porites panamensis is a hermatypic coral present in the eastern Pacific Ocean. Skeletal growth parameters have been reported, but studies of the relationship between annual calcification rates and environmental controls are scarce. In this study, we investigated three aspects of the annual calcification rates of P. panamensis: growth parameters among three P. panamensis populations; the sea surface temperature as a calcification rate control spanning a latitudinal gradient; and calcium carbonate production among three sites. Growth parameters varied among the sites due to the colony growth form. Massive colonies in the north showed a higher calcification rate than encrusting colonies in the south (mean: 1.22-0.49 g CaCO3 · cm-2 · yr-1), where variations in calcification rates were related to growth rate (0.91-0.38 cm · yr-1) rather than to skeletal density differences (overall mean ± SD, 1.31 ± 0.04 g CaCO3 · cm-3). Our results showed a positive linear relationship between annual calcification rates and sea surface temperatures within these P. panamensis populations. Differences were related to distinct oceanographic environments (within and at the entrance of the Gulf of California) with different sea surface temperature regimes and other chemical properties. Different populations calcified under different environmental conditions. Calcium carbonate production was dependent upon the calcification rate and coral cover and so carbonate production was higher in the north (coral cover 12%) than in the south (coral cover 3.5). Thus, the studied sites showed low calcium carbonate production (0.25-0.43 kg CaCO3 · m-2 · yr-1). Our results showed reduced calcification rates, regional temperature regime control over calcification rates, different growth forms, low coral cover and low calcium carbonate production rates in P. panamensis. [ABSTRACT FROM AUTHOR]

To survive, corals possess a variety of active and passive defenses. This study examined the effectiveness of aggregation and cnidae development as defensive strategies in enhancing post-settlement survival and growth of two brooding corals, Favia fragum and Porites astreoides, in Bermuda. Growth and survival of solitary and aggregated spat were monitored over seven weeks; cnidae were extracted from surviving spat. F. fragum aggregated spat had higher mortality, slower growth, and more cnidae than solitary spat. On the other hand, aggregation proved beneficial for P. astreoides spat, which had significantly lower mortality, faster growth, and fewer cnidae. Aggregated and solitary F. fragum spat displayed negative correlations between cnidae density and growth, suggesting a trade-off between defense and growth; however, P. astreoides spat did not demonstrate such a trade-off. These differing responses suggest that early patterns of survivorship and defensive strategies are highly species specific and complex. [ABSTRACT FROM AUTHOR]

Gene expression biomarkers can enable rapid assessment of physiological conditions in situ, providing a valuable tool for reef managers interested in linking organism physiology with large-scale climatic conditions. Here, we assessed the ability of quantitative PCR ( qPCR)-based gene expression biomarkers to evaluate (i) the immediate cellular stress response ( CSR) of Porites astreoides to incremental thermal stress and (ii) the magnitude of CSR and cellular homeostasis response ( CHR) during a natural bleaching event. Expression levels largely scaled with treatment temperature, with the strongest responses occurring in heat-shock proteins. This is the first demonstration of a 'tiered' CSR in a coral, where the magnitude of expression change is proportional to stress intensity. Analysis of a natural bleaching event revealed no signature of an acute CSR in normal or bleached corals, indicating that the bleaching stressor(s) had abated by the day of sampling. Another long-term stress CHR-based indicator assay was significantly elevated in bleached corals, although assay values overall were low, suggesting good prospects for recovery. This study represents the first step in linking variation in gene expression biomarkers to stress tolerance and bleaching thresholds in situ by quantifying the severity of ongoing thermal stress and its accumulated long-term impacts. [ABSTRACT FROM AUTHOR]

The family Poritidae formerly included 6 genera: Alveopora, Goniopora, Machadoporites, Porites, Poritipora, and Stylaraea. Morphologically, the genera can be differentiated based on the number of tentacles, the number of septa and their arrangement, the length of the polyp column, and the diameter of the corallites. However, the phylogenetic relationships within and between the genera are unknown or contentious. On the one hand, Alveopora has been transferred to the Acroporidae recently because it was shown to be more closely related to this family than to the Poritidae by previous molecular studies. On the other hand, Goniopora is morphologically similar to 2 recently described genera, Machadoporites and Poritipora, particularly with regard to the number of septa (approximately 24), but they have not yet been investigated at the molecular level. In this study, we analyzed 93 samples from all 5 poritid genera and Alveopora using 2 genetic markers (the barcoding region of the mitochondrial COI and the ITS region of the nuclear rDNA) to investigate their phylogenetic relationships and to revise their taxonomy. The reconstructed molecular trees confirmed that Alveopora is genetically distant from all poritid genera but closely related to the family Acroporidae, whereas the other genera are genetically closely related. The molecular trees also revealed that Machadoporites and Poritipora were indistinguishable from Goniopora. However, Goniopora stutchburyi was genetically isolated from the other congeneric species and formed a sister group to Goniopora together with Porites and Stylaraea, thus suggesting that 24 septa could be an ancestral feature in the Poritidae. Based on these data, we move G. stutchburyi into a new genus, Bernardpora gen. nov., whereas Machadoporites and Poritipora are merged with Goniopora. [ABSTRACT FROM AUTHOR]

Twenty-two new, extinct species are described from a total of 15 5 Neogene coral species collected from the Indo-West Pacific. Samples are from three sites: the Salayar Limestone, in Sulawesi, Indonesia; the Yalarn Limestone in New Britain, Papua New Guinea, and the Tokelau Limestone Group on Vanua Balavu, Fiji. The oldest are those from Fiji, which span the middle Miocene to the Pliocene, 16.9-6.7 million years ago (Ma). The Papua New Guinean sites occur in the middle Miocene, from 14.8-12.3 Ma. The youngest samples are those collected in Indonesia, from the late Miocene to the early Pleistocene, 5.8-1.4 Ma. The new, although now extinct, species are from the families Acroporidae (Astreopora wa/- laceae n. sp., Montiporapandolfii n. sp., M. wilsonae n. sp., M. teresea n. sp.), Agariciidae (Leptoseris lauensis n. sp.), Dendrophylliidae (Turbinaria jacksoni n. sp.), Euphylliidae (Euphyllia romani n. sp.), Faviidae (Caulastraea cummingae n. sp., C. geoffreyi n. sp., Cyphastrea spinea n. sp., C. aliceae n. sp., C. buddae n. sp., Leptoria hayae n. sp., L. traba n. sp., Platygyra renemai n. sp.), Mussidae (Symphyllia densium n. sp.), Oculinidae (Galaxea salayarensis n. sp., G. kabairaensis n. sp.), Pocilloporidae (Madracis labrum n. sp., Madracis crassisepta n. sp.), and Poritidae (Alveopora jessicae n. sp., A. oliveri n. sp.). Many of the species in this collection reset the age-range of numerous Indo-Pacific taxa and indicate that a Miocene cosmopolitan fauna likely existed prior to and during the closure of the Tethys. [ABSTRACT FROM AUTHOR]

Individual massive coral colonies, primarily faviids and poritids, from three distinct assemblages within the southeastern Arabian Gulf and northwestern Gulf of Oman (United Arab Emirates) were studied from 2006–2009. Annual photographic censuses of approximately 2000 colonies were used to describe the demographics (size class frequencies, abundance, area cover) and population dynamics under “normal” environmental conditions. Size class transitions included growth, which occurred in 10–20% of the colonies, followed in decending order by partial mortality (3–16%), colony fission (<5%) and ramet fusion (<3%). Recruitment and whole colony mortality rates were low (<0.7 colonies/m2) with minimal interannual variation. Transition matrices indicated that the Arabian Gulf assemblages have declining growth rates (λ<1) whereas the massive coral population is stable (λ = 1) in the Gulf of Oman. Projection models indicated that (i) the Arabian Gulf population and area cover declines would be exacerbated under 10-year and 16-year disturbance scenarios as the vital rates do not allow for recovery to pre-disturbance levels during these timeframes, and (ii) the Gulf of Oman assemblage could return to its pre-disturbance area cover but its overall population size would not fully recover under the same scenarios. [ABSTRACT FROM AUTHOR]

To stabilize the taxonomy of the genus Porites in the western Atlantic and provide a foundation from which to launch future taxonomic research, neotypes for the coral species Porites porites and P. divaricata are chosen and Porites verrillii is proposed as a junior synonym of P. astreoides. Colony photographs and stereo scanning electron micrographs are provided of corallites of: 1) neotypes of P. porites (i.e., the P. clavaria holotype) and P. divaricata, 2) the holotypes of P. furcata, P. branneri, P. colonensis, and P. verrillii, and 3) a common P. astreoides. A brief taxonomic history of the genus is also provided. [ABSTRACT FROM AUTHOR]

Coral reefs are declining worldwide due to increased incidence of climate-induced coral bleaching, which will have widespread biodiversity and economic impacts. A simple method to measure the sub-bleaching level of heat-light stress experienced by corals would greatly inform reef management practices by making it possible to assess the distribution of bleaching risks among individual reef sites. Gene expression analysis based on quantitative PCR (qPCR) can be used as a diagnostic tool to determine coral condition in situ. We evaluated the expression of 13 candidate genes during heat-light stress in a common Caribbean coral Porites astreoides, and observed strong and consistent changes in gene expression in two independent experiments. Furthermore, we found that the apparent return to baseline expression levels during a recovery phase was rapid, despite visible signs of colony bleaching. We show that the response to acute heat-light stress in P. astreoides can be monitored by measuring the difference in expression of only two genes: Hsp16 and actin. We demonstrate that this assay discriminates between corals sampled from two field sites experiencing different temperatures. We also show that the assay is applicable to an Indo-Pacific congener, P. lobata, and therefore could potentially be used to diagnose acute heat-light stress on coral reefs worldwide. [ABSTRACT FROM AUTHOR]

Abstract: In this study, coral recruitment was measured on a kilometer-wide scale over two years on shallow (5–6m depth) fringing reefs in St. John, US Virgin Islands, with the objective of determining the extent to which variation in recruitment was affected by biophysical coupling involving temperature and flow. Coral recruitment was measured using settlement tiles deployed at 10 sites along 10km of shore. The tiles were first deployed in August 2006, and thereafter replaced every ≈6months to sample from either August to January, or January to August over 2years. Seawater temperature was recorded at the 10 sites using logging thermistors, and flow was quantified using drogues. Overall, corals recruited at a rate equivalent to 76 corals m−2 6months−1, and were represented mostly by poritids (43% of recruits), agaricids (29%), faviids (17%) and siderastreids (7%). Although the density of recruits differed among sites in a pattern that varied among periods and years, there was a consistent trend for mean density to decline from ≈4 corals tile−1 at eastern sites, to ≤1 coral tile−1 at western sites. One aspect of seawater temperature – the daily range – differed among sites and was greater at western compared to eastern sites, and while it was related inversely to recruitment over one of the sampling periods, it was equivocal as a physical process affecting recruitment. Instead, our results are consistent with biophysical coupling involving patch depletion and downstream filtering, whereby patches of coral larvae are delivered to the south shore of St. John and depleted of larvae through settlement as the water progresses westward. [ABSTRACT FROM AUTHOR]

Growth anomalies (GAs) are common, tumor-like diseases that can cause significant morbidity and decreased fecundity in the major Indo-Pacific reef-building coral genera, Acropora and Porites. GAs are unusually tractable for testing hypotheses about drivers of coral disease because of their pan-Pacific distributions, relatively high occurrence, and unambiguous ease of identification. We modeled multiple disease-environment associations that may underlie the prevalence of Acropora growth anomalies (AGA) (n = 304 surveys) and Porites growth anomalies (PGA) (n = 602 surveys) from across the Indo-Pacific. Nine predictor variables were modeled, including coral host abundance, human population size, and sea surface temperature and ultra-violet radiation anomalies. Prevalence of both AGAs and PGAs were strongly host density-dependent. PGAs additionally showed strong positive associations with human population size. Although this association has been widely posited, this is one of the first broad-scale studies unambiguously linking a coral disease with human population size. These results emphasize that individual coral diseases can show relatively distinct patterns of association with environmental predictors, even in similar diseases (growth anomalies) found on different host genera (Acropora vs. Porites). As human densities and environmental degradation increase globally, the prevalence of coral diseases like PGAs could increase accordingly, halted only perhaps by declines in host density below thresholds required for disease establishment. [ABSTRACT FROM AUTHOR]

The article details a study which described the spatio-temporal variation in coral recruitment in the back reef of Moorea, French Polynesia. The study also examined the association between spatio-temporal variation in coral recruitment and community structure, seawater temperature and wave regimes. The coral recruitment was assessed using settlement tiles that were deployed at 10 sites on the north, southeast and southwest shores from 2005 to 2007. They include acroporids, poritids and pocilloporids. Study authors hypothesized that coral recruitment in the back reef of Moorea is influenced by the interaction of seasonal variation in wave exposure, family-level differences in coral reproductive timing, and spatial distribution of adult corals.

Abstract: Coral reefs in Jakarta Bay have been subjected to scientific studies since the 1920s. Also from that time on biological collections were made. The reefs in the Jakarta Bay have been under long-term natural and anthropogenic stress. With the biological collections and historical documents the coral species richness in Jakarta Bay around 1920 was reconstructed. New data from this bay and the adjacent offshore Thousand Islands archipelago were obtained during a 2005 research expedition. A comparison of the coral assemblages between 1920 and 2005 reveals a clear decline in species numbers. The most prominent results include the near-shore disappearance of species belonging to the families Acroporidae, Milleporidae, and to a lesser extent Poritidae. The overall coral species composition of the reefs has changed considerably, which is partly reflected in a strong decline in coral species richness. About half the number of species recorded in 1920 was found again in 2005. [ABSTRACT FROM AUTHOR]

The extent to which fish communities are structured by spatial variability in coral reef habitats versus stochastic processes (such as larval supply) is very important in predicting responses to sustained and ongoing habitat degradation. In this study, butterflyfish and benthic communities were surveyed annually over 15 years on 47 reefs (spanning 12° of latitude) of the Great Barrier Reef (GBR). Spatial autocorrelation in the structure of butterflyfish communities versus key differences in reef habitats was investigated to assess the extent to which the structure of these fish communities is influenced by habitat conditions. Benthic communities on each of the 47 reefs were broadly categorised as either: 1. Poritidae/Alcyoniidae, 2. mixed taxa, 3. soft coral or 4. Acropora-dominated habitats. These habitat types most reflected increases in water clarity and wave exposure, moving across the GBR shelf from coastal to outer-shelf environments. In turn, each habitat type also supported very distinct butterflyfish communities. Hard coral feeders were always the dominant butterflyfish species in each community type. However, the numerically dominant species changed according to habitat type, representing spatial replacement of species across the shelf. This study reveals clear and consistent differences in the structure of fish communities among reefs associated with marked differences in habitat structure. [ABSTRACT FROM AUTHOR]

Andaman and Nicobar Islands are the most diverse areas with enriched marine organisms. Presence of corals in any area shows the enriched productivity of marine ecosystem of that area. The coral helps the other associated faunal communities for their survival as well as their way of life towards the future generation. Seven species of scleractinian corals are recognized as the new records to Indian water as the survey made in Neil, Tarmugli and Car Nicobar Islands of Andaman & Nicobar Archipelago. They are — Acropora tanegashimensis (Veron, 1990), Acropora insignis (Nemenzo, 1967), Favites paraflexuosa (Veron,2002), Favites spinosa (Klunzinger, 1879), Solenastrea bournoni (Milne Edwards and Haime, 1849), Porites porites (Pallas, 1766) and Seriatopora aculeate (Quelch, 1846). These scleractinian corals belong to Acroporidae, Faviidae, Poritidae and Pocilloporidae families. The present investigation deals with their morphological characteristics with relative nomenclatural attributes to draw the ideal identifying remarks. [ABSTRACT FROM AUTHOR]

Spatiotemporal recruitment patterns of scleractinian corals were investigated around Iriomote Island, Ryukyu Archipelago, Japan, in relation to adult coral cover in 2005 and 2006. Although almost all corals were broadcasting spawners, the relationship between recruitment and adult coral cover differed among coral families (Acroporidae, Poritidae, and Pocilloporidae), likely due to differences in embryonic development time. For spawning pocilloporid corals, whose larvae develop relatively more rapidly, recruitment was higher at sites where adult coral cover was higher. In contrast, recruitment was not related to adult coral cover in acroporid and poritid corals, whose embryonic development times were relatively slow. Moreover, recruitment of acroporid corals varied between years, and recruitment was greater at leeward compared to windward reefs for a few days after spawning. These results suggest that embryonic development time and wind-driven surface currents affect larval dispersal and subsequent recruitment patterns at a local scale. Based on embryonic development time, some spawning corals are more likely to have higher rates of self-seeding than others. Our results predict that among spawning corals, local populations of acroporid and poritid corals, whose larvae potentially disperse over long distances and recruit in neighboring reefs, are more resilient to local disturbances than those of pocilloporid corals, whose recruitment relies upon local stock. [ABSTRACT FROM AUTHOR]

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This study tested the effects of acclimatization on the response of corals to elevated temperature, using juvenile massive Porites spp. and branching P. irregularis from Moorea (W149°50′, S17°30′). During April and May 2006, corals were acclimatized for 15 days to cool (25.7°C) or ambient (27.7°C) temperature, under shaded (352 μmol photons m−2 s−1) or ambient (554 μmol photons m−2 s−1) natural light, and then incubated for 7 days at ambient or high temperature (31.1°C), under ambient light (659 μmol photons m−2 s−1). The response to acclimatization was assessed as biomass, maximum dark-adapted quantum yield of PSII ( Fv/ Fm), and growth, and the effect of the subsequent treatment was assessed as Fv/ Fm and growth. Relative to the controls (i.e., ambient temperature/ambient light), massive Porites spp. responded to acclimatization through increases in biomass under ambient temperature/shade, and low temperature/ambient light, whereas P. irregularis responded through reduced growth under ambient temperature/shade, and low temperature/ambient light. Acclimatization affected the response to thermal stress for massive Porites spp. (but not P. irregularis), with an interaction between the acclimatization and subsequent treatments for growth. This interaction resulted from a lessening of the negative effects of high temperature after acclimatizing to ambient temperature/shade, but an accentuation of the effect after acclimatizing to low temperature/shade. It is possible that changes in biomass for massive Porites spp. are important in modulating the response to high temperature, with the taxonomic variation in this effect potentially resulting from differences in morphology. These results demonstrate that corals can acclimatize during short exposures to downward excursions in temperature and light, which subsequently affects their response to thermal stress. Moreover, even con-generic taxa differ in this capacity, which could affect coral community structure. [ABSTRACT FROM AUTHOR]

Methods for U-series dating of corals are described using a multi-collector (MC) ICPMS. The utility of this approach is illustrated with two examples: first, dating of Last Interglacial (∼105 years) corals from southwestern Western Australian; and second, the dating of near-modern (100 to 102 years) corals from the Great Barrier Reef. A previously unreported occurrence of Last Interglacial corals from the southernmost tip (Cape Leeuwin) of Western Australia is shown to have U-series ages ranging from 129 to 125 ka, indicating that relatively prolific coral growth occurred during the first half of the Last Interglacial period. This represents an extension of the southernmost limit of coral growth by almost ∼300-400 km compared with present-day limits, requiring significantly warmer (∼2°C) sea-surface temperatures, consistent with intensification of the Leeuwin Current. Furthermore, at this southernmost site, corals are preserved in growth position at heights of 2-2.5 m above present-day sea-level, confirming previous observations from along the stable coastal margin of Western Australia that sea-levels were ∼3 m higher during the first part of the Last Interglacial. The substantially improved sensitivity of MC-ICPMS is illustrated by 238U-230Th dating of modern coral samples extracted from a living Porites colony from the Great Barrier Reef. The 238U-230Th ages from annual samples are in excellent agreement with an independent chronology derived by counting of annual density bands and show that the coral grew continuously from 400 years ago to the present day. The typical precision achievable for corals ranging in age from tens to hundreds of years is shown to be 2-5 years, with the main limitation being uncertainties in the correction for initial non-radiogenic 230Th. [ABSTRACT FROM AUTHOR]

GFP-like fluorescent proteins (FPs) are the key color determinants in reef-building corals (class Anthozoa, order Scleractinia) and are of considerable interest as potential genetically encoded fluorescent labels. Here we report 40 additional members of the GFP family from corals. There are three major paralogous lineages of coral FPs. One of them is retained in all sampled coral families and is responsible for the non-fluorescent purple-blue color, while each of the other two evolved a full complement of typical coral fluorescent colors (cyan, green, and red) and underwent sorting between coral groups. Among the newly cloned proteins are a ''chromo-red'' color type from Echinopora forskaliana (family Faviidae) and pink chromoprotein from Stylophora pistillata (Pocilloporidae), both evolving independently from the rest of coral chromoproteins. There are several cyan FPs that possess a novel kind of excitation spectrum indicating a neutral chromophore ground state, for which the residue E167 is responsible (numeration according to GFP from A. victoria). The chromoprotein from Acropora millepora is an unusual blue instead of purple, which is due to two mutations: S64C and S183T. We applied a novel probabilistic sampling approach to recreate the common ancestor of all coral FPs as well as the more derived common ancestor of three main fluorescent colors of the Faviina suborder. Both proteins were green such as found elsewhere outside class Anthozoa. Interestingly, a substantial fraction of the all-coral ancestral protein had a chromohore apparently locked in a non-fluorescent neutral state, which may reflect the transitional stage that enabled rapid color diversification early in the history of coral FPs. Our results highlight the extent of convergent or parallel evolution of the color diversity in corals, provide the foundation for experimental studies of evolutionary processes that led to color diversification, and enable a comparative analysis of structural determinants of different colors. [ABSTRACT FROM AUTHOR]

Elevated sea surface temperatures in the late 1990s were associated with widespread coral mortality in the Arabian Gulf, particularly in Acropora dominated areas. This study investigates the composition, condition, and recruitment patterns of coral communities in Saih Al-Shaib, Dubai, United Arab Emirates, a decade after mass bleaching. Five statistically distinct communities were identified by cluster analysis, with grouping optimized from 17 significant indicator species. Overall, 25 species of scleractinian coral were observed, representing 35 ± 1.6% coral cover. Densities of recruits were low (0.8 ± 0.2 m−2), and composition generally reflected that of the surrounding adult community. Ten years after mass mortality, Acropora dominated assemblages were observed in three of the six sites examined and coral cover (41.9 ± 2.5%) was double post-bleaching cover. One shallow near-shore site appears to have had recovery of Acropora reset by a further bleaching event in 2002. However, the prevalence of young Acropora colonies here indicates that recovery may recur in several years. One area formerly dominated by Acropora is now dominated by faviids and poritids, with adult and juvenile composition suggesting this dominance shift is likely to persist. Porites lutea and Porites harrisoni dominated communities were negligibly impacted by the bleaching events, and the limited change in coral cover and composition in intervening years likely results from slow growth and low recruitment. Despite strong recovery of several dominant Acropora species, five formerly common species from this area were not observed suggesting local extinction. Dubai coral communities exhibit both resistance and resilience to elevated sea temperatures. The conservation of these patch reefs is warranted given the predicted increase in bleaching events, and the role that these communities may play in regional recovery. [ABSTRACT FROM AUTHOR]

A wide range of bicarbonate concentrations was used to monitor the kinetics of bicarbonate (HCO3−) use in both photosynthesis and calcification in two reef-building corals, Porites porites and Acropora sp. Experiments carried out close to the P. porites collection site in Barbados showed that additions of NaHCO3 to synthetic seawater proportionally increased the calcification rate of this coral until the concentration exceeded three times that of seawater (6 mM). Photosynthetic rates were also stimulated by HCO3− addition, but these became saturated at a lower concentration (4 mM). Similar experiments on aquarium-acclimated colonies of Indo-Pacific Acropora sp. showed that calcification and photosynthesis in this coral were enhanced to an even greater extent than P. porites, with calcification continuing to increase above 8 mM HCO3−, and photosynthesis saturating at 6 mM. Calcification rates of Acropora sp. were also monitored in the dark, and, although these were lower than in the light for a given HCO3− concentration, they still increased dramatically with HCO3− addition, showing that calcification in this coral is light stimulated but not light dependent. [ABSTRACT FROM AUTHOR]

Part of an extensive fossil reef composed of corals attributed to Porites panamensis is exposed in cross section along the walls of Cañada Coronados on the south side of Isla Cononados in the Gulf of California, near Loreto, Baja California Sur (Mexico). Based on laboratory analysis of uranium/thorium isotope ratios derived from a coral sample, the reef developed sometime between 121,000 and 127,000 years ago during a highstand in sea level correlative with marine isotope substage 5e. Densely packed bouquet-shaped colonies with multiple branches reach a maximum height of 1.1 m and maximum diameter of 1.1 m. Colony size diminishes markedly in the landward direction. About 60% of the corals show growth from an attachment point on andesite cobbles or small boulders. These clasts formed a debris apron on the floor of a large lagoon that effectively stabilized carbonate sand derived from crushed rhodoliths. Associated with the cobbled surface is a transitional intertidal biota that includes clast-encrusting coralline red algae, fixed bivalves such as Pseudochama janus, Modiolus capax, Barbatia reevseana, and Arca pacifica, in addition to gastropods such as Turbo fluctuosus, Acanthina tuberculata, and Nerita bernhardi. The succeeding reef body covered a minimum area of 1.3 ha. Using a conservative estimate of one coral colony per square meter, the reef deposit at Cañada Coronados represents the coalescence of 13,000 colonies. ot strictly coeval in ecological age, additional reef structures may have occupied up to 50 ha around the Cañada Coronados site in Isla Coronados. The southern exposure of fossil reefs on Isla Coronados is a pattern commonly found on other islands and sheltered bays on the peninsular coast in the lower Gulf of California. [ABSTRACT FROM AUTHOR]

We tested the rarely considered hypothesis that the ultraviolet portion (UVR, 280–400 nm) of the light spectrum affects patterns of recruitment in reef-building corals. The premise for this hypothesis rests in the fact that biologically relevant intensities of UVR penetrate to considerable depths (>24 m) in the clear waters surrounding many coral reefs, and that reef organisms allocate substantial resources to prevent and repair UVR damage. The ability of larvae spawned by the brown morph of the Caribbean coral, Porites astreoides, to detect and avoid UVR was assessed in petri dishes where one-half of the dish was shielded from UVR and the other exposed. Observations made every 30 min between 10:30 and 13:30 h showed significantly higher densities of larvae swimming in regions shielded from UVR. To determine how this behavior affects settlement patterns, larvae collected from P. astreoides adults at 18 m depth were released into chambers deployed at 17 m depth where they were given a choice of three different light regions in which to settle: PAR (PAR=400–700 nm), PAR+UVAR (UVAR=320–400 nm), and PAR+UVAR+UVBR (UVBR=280–320 nm). At the end of the experiment, greater numbers of P. astreoides larvae had settled in the region of the tube where UVR was reduced than would be expected if dispersion were random. To our knowledge, this is the first demonstration in any reef-building coral species that planula larvae can detect UVR and that it affects their choice of a settlement site. These results indicate that the capacity to detect and avoid habitats with biologically damaging levels of UVR may be one factor contributing to the successful recruitment of coral larvae. [ABSTRACT FROM AUTHOR]

Porites sverdrupi has long been considered to be an ecotype of the more abundant and widespread species P. panamensis, but multivariate comparisons of corallite characteristics indicate that P. sverdrupi is morphologically distinct and thus represents a valid species. In these analyses, linear measurements and counts were made on 72 colonies of the two species (53 of P. panamensis and 19 of P. sverdrupi), and analyzed multivariately using canonical discriminant analysis. Generally, corallite characteristics of P. sverdrupi are larger in size than P. panamensis. Important characters in the discriminant function (e.g., number of bifurcate septa, wall thickness, and dorsal septum length) have not been recognized in previous studies of Porites in either the Indo-Pacific or Atlantic regions as being significant in distinguishing among poritid species. In addition to corallite characteristics, P. sverdrupi is unique in its ecological habit, colony form, and geographic distribution. [ABSTRACT FROM AUTHOR]

Compounded disturbances are becoming increasingly common on coral reefs. Impacts of global warming, which is generally perceived as the most serious threat to coral reefs today, often coincide with various common anthropogenic disturbances, such as pollution and overharvesting. To better evaluate the impact of global warming, interactions between elevated temperature and background disturbance should be investigated. In this study, the physiological response of the reef-building coral Porites cylindrica was investigated, when exposed to enrichment of dissolved inorganic nitrate (+15 μM for 14 days) and elevated seawater temperature (+2ºC for 48 h), in the absence of particulate food. It was shown that P. cylindrica was able to tolerate the temperature exposure without losing symbiotic microalgae or chlorophyll pigments, although the photosynthetic capacity was affected. Nitrate enrichment significantly reduced primary production rate, although zooxanthella population density and chlorophyll concentrations were not affected. The combination of elevated temperature and nitrate enrichment produced an even more pronounced reduction of the production rate. Since coral respiration rate remained unaffected by the treatments, this implies that the corals were unable to acclimate to impaired photosynthesis. However, there was no indication of subsequently reduced tissue growth or increased host catabolism based on tissue biomass measurements. On the other hand, all corals, including controls, lost tissue biomass during the exposure, suggesting a dependence on particulate food. Our results imply that corals on nutrient-exposed reefs may be more stressed during periods of elevated temperature, compared to corals in more pristine areas. [ABSTRACT FROM AUTHOR]

The occurrence and intensity of luminescent lines was assessed by eye in slices from 232 similar-sized colonies of massive Porites from 30 reefs on the Great Barrier Reef (GBR), Australia. The reefs varied in location from coastal to 176 km from the mainland. Luminescent lines in corals of the GBR record periods when corals are exposed to river plumes and other mainland runoff. Reefs could be divided into three groups: those that never recorded runoff, those that recorded runoff but not every year, and those that recorded runoff every year. The average intensity of the luminescent lines was significantly inversely related to the percentage distance of a reef across the shelf and to the average water depth between a reef and the mainland. Annual variations in luminescence intensity were also significantly correlated with instrumental measurements of annual river flow and modeled salinities. These results suggest that luminescent lines in massive corals are a highly robust proxy record of mainland influence on reefs along the length of the GBR. [ABSTRACT FROM AUTHOR]