Search

The future of coral reefs under increasing CO2 depends on their capacity to recover from disturbances. To predict the recovery potential of coral communities that are fully acclimatized to elevated CO2, we compared the relative success of coral recruitment and later life stages at two volcanic CO2 seeps and adjacent control sites in Papua New Guinea. Our field experiments showed that the effects of ocean acidification (OA) on coral recruitment rates were up to an order of magnitude greater than the effects on the survival and growth of established corals. Settlement rates, recruit and juvenile densities were best predicted by the presence of crustose coralline algae, as opposed to the direct effects of seawater CO2. Offspring from high CO2 acclimatized parents had similarly impaired settlement rates as offspring from control parents. For most coral taxa, field data showed no evidence of cumulative and compounding detrimental effects of high CO2 on successive life stages, and three taxa showed improved adult performance at high CO2 that compensated for their low recruitment rates. Our data suggest that severely declining capacity for reefs to recover, due to altered settlement substrata and reduced coral recruitment, is likely to become a dominant mechanism of how OA will alter coral reefs. [ABSTRACT FROM AUTHOR]

The recovery of bleached corals is crucial in ensuring the persistence of the coral reef ecosystem function. This study investigated whether relocating bleachedPlatygyra sinensiscolonies was a viable measure to accelerate their recovery. During a mild bleaching event in 2014, eight bleached colonies ofP. sinensiswere relocated from an affected reef at Sultan Shoal, Singapore, to a reef at Kusu that was less impacted. Another eight colonies at Sultan Shoal were tagged as controls. After five months, 88% of relocated bleached colonies at Kusu showed full recovery whereas only 25% of the control bleached colonies at Sultan Shoal had recovered. The differential coral recovery among the two sites was most likely due to lower seawater temperatures and faster water flow at Kusu, which helped to mitigate the effects of thermal stress on the bleached corals. This relocation study demonstrated that relocating bleachedP. sinensisto sites with more favourable environmental conditions is a viable approach to reduce bleaching impacts for this species. [ABSTRACT FROM AUTHOR]

Critical to determining vulnerability or resilience of reef corals to Ocean Acidification (OA) is a clearer understanding of the extent to which corals can control carbonate chemistry in their Extracellular Calcifying Medium (ECM) where the CaCO 3 skeleton is produced. Here, we employ a mathematical framework to calculate ECM aragonite saturation state (Ω arag.(ECM) ) and carbonate system ion concentration using measurements of calcification rate, seawater characteristics (temperature, salinity and pH) and ECM pH (pH (ECM) ). Our calculations of ECM carbonate chemistry at current-day seawater pH, indicate that Ω arag.(ECM) ranges from ∼10 to 38 (mean 20.41), i.e. about 5 to 6-fold higher than seawater. Accordingly, Dissolved Inorganic Carbon (DIC) and Total Alkalinity (TA) were calculated to be around 3 times higher in the ECM than in seawater. We also assessed the effects of acidification on ECM chemical properties of the coral Stylophora pistillata . At reduced seawater pH our calculations indicate that Ω arag.(ECM) remains almost constant. DIC (ECM) and TA (ECM) gradually increase as seawater pH declines, reaching values about 5 to 6-fold higher than in seawater, respectively for DIC and TA. We propose that these ECM characteristics buffer the effect of acidification and explain why certain corals continue to produce CaCO 3 even when seawater chemistry is less favourable. [ABSTRACT FROM AUTHOR]

With the ongoing loss of coral cover and the associated flattening of reef architecture, understanding the links between coral habitat and reef fishes is of critical importance. Here, we investigate whether considering coral traits and functional diversity provides new insights into the relationship between structural complexity and reef fish communities, and whether coral traits and community composition can predict structural complexity. Across 157 sites in Seychelles, Maldives, the Chagos Archipelago, and Australia's Great Barrier Reef, we find that structural complexity and reef zone are the strongest and most consistent predictors of reef fish abundance, biomass, species richness, and trophic structure. However, coral traits, diversity, and life histories provided additional predictive power for models of reef fish assemblages, and were key drivers of structural complexity. Our findings highlight that reef complexity relies on living corals-with different traits and life histories-continuing to build carbonate skeletons, and that these nuanced relationships between coral assemblages and habitat complexity can affect the structure of reef fish assemblages. Seascape-level estimates of structural complexity are rapid and cost effective with important implications for the structure and function of fish assemblages, and should be incorporated into monitoring programs. [ABSTRACT FROM AUTHOR]

In 2002, bleaching was reported throughout many Indo-Pacific coral-reef regions, including French Polynesia. Bleaching occurred again in French Polynesia in 2003, providing an opportunity to compare the effects of successive bleaching events on coral susceptibility. During 2002 and 2003, underwater video surveys were completed in stations at four depths (lagoon: 0-2, 2-4 m; outer reef slope: 6-8, 12-14 m) at two locations on the northern and northwestern coast of Moorea (Society Archipelago) to compare the cover of healthy-appearing, the cover of partially bleached and the cover of fully bleached coral. Bleaching patterns were genus specific and differences in susceptibility among major genera were generally consistent between 2002 and 2003, with Acropora showing the greatest susceptibility. Some genera exhibited substantial spatial variability in bleaching susceptibility between years (e.g. Pocillopora, Montipora); however, this variability was significant only for fully bleached and partially bleached Acropora. Multivariate analyses showed that spatial patterns in the proportion of healthy-appearing coral were similar over time within the assemblages, whereas the cover of partially bleached and the cover of fully bleached coral were more variable among depths and locations. This variability has important implications for assessing changes to coral community structure over time and for estimating coral-reef resistance and resilience to future bleaching disturbance. [ABSTRACT FROM AUTHOR]

The present study aimed to determine the current status of corals using the coral video transect (CVT) method in the east coast, west coast, and isolated areas of Tioman Island, Peninsular Malaysia. A total of 65 genera from 21 families of corals were identified, from which the scleractinian corals of Acropora, Montipora, and Porites were dominant in the coral assemblages. Nine reef sites were categorised as having 'good' (51.4%-60.3%) coral condition and four reef sites as having 'fair' (37.6%-49.2%) coral condition. This study concluded that the reefs around Tioman Island were in 'good' average coral condition and have high generic diversity with mixed coral morphological structures. The east coast and isolated areas had better live coral cover compared to the west coast area due to less coastal development and human impacts. [ABSTRACT FROM AUTHOR]

Although cold-water coral (CWC) biology, physiology, and connectivity, have been extensively studied, few studies have so far focused on their reproductive biology. The reproductive biology of colonies of the reef-building Lophelia pertusa (Linnaeus 1758), now synonymised as Desmophyllum pertusum , and Madrepora oculata (Linnaeus 1758) from the Mediterranean Sea, an area particularly exposed to the effects of anthropogenic pressures, was investigated for the first time using histological techniques. Samples were collected from the Lacaze-Duthiers canyon in the Gulf of Lion, northwestern Mediterranean Sea, where the corals are living at 13 °C, close to their upper limit of thermal tolerance. The gametogenic cycle suggests a seasonal spawning of D. pertusum in autumn to early winter, similarly to population from the Gulf of Mexico. This period corresponds to the formation of storm-induced deep-sea water plumes, likely acting as a time giver for coral spawning and facilitates larval dispersal. Madrepora oculata shows continuous reproduction as already identified in eastern and western North Atlantic, with reproductive features of a species less opportunistic than D. pertusum , consistent with its other biological characteristics. This difference between the two species is of paramount importance to define strategies of conservation. • First data on the reproduction of two cold-water corals in the Mediterranean Sea. • Potential spawning date in autumn and/or early winter for Desmophyllum pertusum. • Role of deep-sea currents in timing of spawning for this species. • Madrepora oculata harbor different strategy, with a continuous reproduction. [ABSTRACT FROM AUTHOR]

Predictive habitat suitability models are powerful tools for cost-effective, statistically robust assessment of the environmental drivers of species distributions. The aim of this study was to develop predictive habitat suitability models for two genera of scleractinian corals (Leptoserisand Montipora) found within the mesophotic zone across the main Hawaiian Islands. The mesophotic zone (30–180 m) is challenging to reach, and therefore historically understudied, because it falls between the maximum limit of SCUBA divers and the minimum typical working depth of submersible vehicles. Here, we implement a logistic regression with rare events corrections to account for the scarcity of presence observations within the dataset. These corrections reduced the coefficient error and improved overall prediction success (73.6% and 74.3%) for both original regression models. The final models included depth, rugosity, slope, mean current velocity, and wave height as the best environmental covariates for predicting the occurrence of the two genera in the mesophotic zone. Using an objectively selected theta (“presence”) threshold, the predicted presence probability values (average of 0.051 for Leptoseris and 0.040 for Montipora) were translated to spatially-explicit habitat suitability maps of the main Hawaiian Islands at 25 m grid cell resolution. Our maps are the first of their kind to use extant presence and absence data to examine the habitat preferences of these two dominant mesophotic coral genera across Hawai‘i.

Recent surveys conducted on Reunion Island coral reefs revealed an atypical manifestation of black band disease on the main framework building coral, Porites lutea. This BBD manifestation (PorBBD) presented a thick lighter-colored band, which preceded the typical BBD lesion. Whilst BBD aetiology has been intensively described worldwide, it remains unclear if corals with apparently similar lesions across coral reefs are affected by the same pathogens. Therefore, a multidisciplinary approach involving field surveys, gross lesion monitoring, histopathology and 454-pyrosequencing was employed to provide the first comprehensive characterization of this particular manifestation. Surveys conducted within two geomorphological zones over two consecutive summers and winters showed spatial and seasonal patterns consistent with those found for typical BBD. Genetic analyses suggested an uncharacteristically high level of Vibrio spp. bacterial infection within PorBBD. However, microscopic analysis revealed high densities of cyanobacteria, penetrating the compromised tissue as well as the presence of basophilic bodies resembling bacterial aggregates in the living tissue, adjacent to the bacterial mat. Additionally, classical BBD-associated cyanobacterial strains, genetically related to Pseudoscillatoria coralii and Roseofilum reptotaenium were identified and isolated and the presence of sulfate-reducers or sulfide-oxidizers such as Desulfovibrio and Arcobacter, previously shown to be associated with anoxic microenvironment within typical BBD was also observed, confirming that PorBBD is a manifestation of classical BBD.

We examined the ability of scleractinian corals with different polyp sizes to remove picoeukaryotes by predation and the effect of coral exudates on picoeukaryote growth. Experiments were conducted by adding picoeukaryotes to Stylophora pistillata (SP) and Montipora stellata (MS). Within six hours the picoeukaryote concentration in the SP and MS tanks was significantly lower than the control without corals. SP showed higher overall activity than MS, and the particle removal activity of MS decreased in light conditions. Picoeukaryotes exposed to SP exudates grew significantly denser than those exposed to MS exudates or those in water without coral exudates. Dissolved organic carbon concentrations in the SP tanks were also significantly higher. We concluded that the picoeukaryote removal rates were higher in S. pistillata than in M. stellata, and coral exudates can reciprocally enhance picoeukaryote growth.

Summary Ocean acidification is an ongoing threat for marine organisms due to the increasing atmospheric CO2 concentration. Seawater acidification has a serious impact on physiologic processes in marine organisms at all life stages. On the other hand, potential tolerance to external pH changes has been reported in coral larvae. Information about the possible mechanisms underlying such tolerance responses, however, is scarce. In the present study, we examined the effects of acidified seawater on the larvae of Acropora digitifera at the molecular level. We targeted two heat shock proteins, Hsp70 and Hsp90, and a heat shock transcription factor, Hsf1, because of their importance in stress responses and in early life developmental stages. Coral larvae were maintained under the ambient and elevated CO2 conditions that are expected to occur within next 100 years, and then we evaluated the expression of hsps and hsf1 by quantitative real-time polymerase chain reaction (PCR). Expression levels of these molecules significantly differed among target genes, but they did not change significantly between CO2 conditions. These findings indicate that the expression of hsps is not changed due to external pH changes, and suggest that tolerance to acidified seawater in coral larvae may not be related to hsp expression.

This study presents an analysis of reef bioconstructors at the Rocas Atoll, Brazil’s Northeast, sampled in January and February 2008. The results showed the presence of a community made up mainly of calcareous algae (Porolithon pachydermum, Sporolithon sp., Lithoporella sp., Lithophyllum sp.), corals (Siderastrea stellata, Favia gravida), vermetid mollusks (Dendropoma irregulare, Petaloconchus varians), and foraminifers (Homotrema rubrum) in the reef formation. This taxonomic survey shows the importance of a different species during the carbonate growth process of the only atoll in the Equatorial South Atlantic.

Calcification in photosynthetic scleractinian corals is a complicated process that involves many different biological, chemical, and physical sub-processes that happen within and around the coral tissue. Identifying and quantifying the role of separate processes in vivo or in vitro is difficult or not possible. A computational model can facilitate this research by simulating the sub-processes independently. This study presents a spatio-temporal model of the calcification physiology, which is based on processes that are considered essential for calcification: respiration, photosynthesis, Ca2＋-ATPase, carbonic anhydrase. The model is used to test different hypotheses considering ion transport across the calicoblastic cells and Light Enhanced Calcification (LEC). It is also used to quantify the effect of ocean acidification (OA) on the Extracellular Calcifying Medium (ECM) and ATP-consumption of Ca2＋-ATPase. It was able to reproduce the experimental data of three separate studies and finds that paracellular transport plays a minor role compared to transcellular transport. In the model, LEC results from increased Ca2＋-ATPase activity in combination with increased metabolism. Implementing OA increases the concentration of CO 2 throughout the entire tissue, thereby increasing the availability of C O 3 − in the ECM. As a result, the model finds that calcification becomes more energy-demanding and the calcification rate increases. • Several hypotheses on coral calcification are tested using a computational model. • The model is able to reproduce the experimental data of three separate studies. • The model finds that paracellular ion transport into the ECM plays a minor role. • Implementing OA in the model increased the calcification rate and ATP consumption. • In the model, LEC is the result of increased metabolism and Ca 2 + -ATPase activity. [ABSTRACT FROM AUTHOR]

Marked shifts in the composition of coral assemblages are occurring at many locations, but it is unknown whether these are permanent shifts reinforced by patterns of population replenishment. This study examined the composition of juvenile coral assemblages across the United Arab Emirates (UAE). Densities of juvenile corals varied significantly among locations, but were highest where coral cover was highest. Juvenile coral assemblages within the Persian Gulf were dominated by Porites , while no Acropora were recorded. We expect therefore, continued declines in Acropora abundance, while observed dominance of Porites is likely to persist. In the Oman Sea, Pocillopora was the dominant juvenile coral, with Acropora and Stylophora also recorded. This study shows that taxonomic differences in replenishment are reinforcing temporal shifts in coral composition within the southern Persian Gulf, but not in the Oman Sea. Differences in environmental conditions and disturbance regimes likely explain the divergent responses between regions. [ABSTRACT FROM AUTHOR]

Great Nicobar Island is the southernmost island of Andaman and Nicobar group of islands and largest island of Nicobar group included in UNESCO-MAB-Network of biosphere reserve. The island is inhabited by a total of 173 species of scleractinian corals from 6 different study areas among the 577 species reported from entire Andaman and Nicobar Islands. The Shannon-Weiner diversity index ranged from 2.84 to 4.45 while the Simpson's density index ranges from 0.93 to 0.99. Among the study areas, it was seen that the Laxman Beach is most diverse in comparison with the other 5 areas. Presence of 29.98 % scleractinian coral species in Great Nicobar Island denotes the sense of ecological attributes behind the sustainable support towards the coral settlement, growth and development. [ABSTRACT FROM AUTHOR]

Miocene coral-bearing limestones, distributed in the western Makran Basin, are attributed to Aquitanian and Burdigalian. This investigation is focused on three Early Miocene coral-bearing limestone sections in western Makran. Remarkably, well-preserved scleractinian corals and other components could be very definitive to reconstruct paleoenvironmental conditions. Lithologically, there are some differences between the studied sections. Furthermore, zooxanthellate corals are diverse and abundant in all sections. Based on different components and richness of zooxanthellate corals, it seems that the studied carbonate corals are precipitated in a subtropical condition, between 19 and 20 °C in all sections. In light of the dominancy of corals, the presence of symbiont-bearing larger benthic foraminifera (LBF), lithological features, bioeroding features, and encrusting organisms, the oligotrophic to slightly mesotrophic conditions are considered for Tejek section and the mesotrophic condition had been prevailed in Kermestan and Irer sections. According to light intensity in water column and coral morphotypes, Tejek section is considered to precipitate under euphotic to slightly mesophotic condition, while Kermestan and Irer sections were deposited under mesophotic to euphotic light conditions. In transparent water, photic zones continue to deeper depths, while in less transparent water, these zones are limited to shallower parts. A defined depth in the photic zone may represent euphotic, mesophotic, or oligophotic zone. Based on the water transparency, a taxon in a defined photic zone can occur in various depths. On the basis of trophic-light intensity-depth chart, the estimated depth ranges are 12-85 m for Tejek section and 5-62 m for Kermestan and Irer sections. Water energy as another important factor in environmental condition is acquired from coral morphotypes. Accordingly, Tejek section is precipitated under moderate-high energy and Kermestan and Irer sections are deposited in low to moderate-high energy. The presence of encrusting coralline algae, corals, and other constituents is indicative of different substrates in the studied areas. Corals favorably develop in normal salinity waters. The existence of colonial corals and occurrence of benthic foraminifera with hyaline wall indicate normal seawater conditions. [ABSTRACT FROM AUTHOR]

Coral reefs maintain extraordinary biodiversity and provide protection from tsunamis and storm surge, but inshore coral reef health is degrading in many regions due to deteriorating water quality. Deconvolving natural and anthropogenic changes to water quality is hampered by the lack of long term, dated water quality data but such records are required for forward modelling of reef health to aid their management. Reef corals provide an excellent archive of high resolution geochemical (trace element) proxies that can span hundreds of years and potentially provide records used through the Holocene. Hence, geochemical proxies in corals hold great promise for understanding changes in ancient water quality that can inform broader oceanographic and climatic changes in a given region. This article reviews and highlights the use of coral-based trace metal archives, including metal transported from rivers to the ocean, incorporation of trace metals into coral skeletons and the current ‘state of the art’ in utilizing coral trace metal proxies as tools for monitoring various types of local and regional source-specific pollution (river discharge, land use changes, dredging and dumping, mining, oil spills, antifouling paints, atmospheric sources, sewage). The three most commonly used coral trace element proxies (i.e., Ba/Ca, Mn/Ca, and Y/Ca) are closely associated with river runoff in the Great Barrier Reef, but considerable uncertainty remains regarding their complex biogeochemical cycling and controlling mechanisms. However, coral-based water quality reconstructions have suffered from a lack of understanding of so-called vital effects and early marine diagenesis. The main challenge is to identify and eliminate the influence of extraneous local factors in order to allow accurate water quality reconstructions and to develop alternate proxies to monitor water pollution. Rare earth elements have great potential as they are self-referencing and reflect basic terrestrial input. [ABSTRACT FROM AUTHOR]

Corals aremixotrophs: they are able to fix inorganic carbon through the activity of their symbiotic dinoflagellates and to gain nitrogen from predation on plankton and uptake of dissolved organic and inorganic nutrients. They also live in close association with diverse diazotrophic communities, inhabiting their skeleton, tissue and mucus layer, which are able to fix dinitrogen (N2). The quantity of fixed N2 transferred to the corals and its distribution within coral compartments as well as the quantity of nitrogen assimilated through the ingestion of planktonic diazotrophs are still unknown. Here, we quantified nitrogen assimilation via (i) N2 fixation by symbiont diazotrophs, (ii) ingestion of cultured unicellular diazotrophs and (iii) ingestion of natural planktonic diazotrophs. We estimate that the ingestion of diazotrophs provides 0.76±0.15 μg N cm-2 h-1, suggesting that diazotrophs represent a non-negligible source of nitrogen for scleractinian corals. [ABSTRACT FROM AUTHOR]

Rapa (27°36′ S, 144°20′ W) is a small (~40 km2) volcanic island isolated in the Southern Austral Archipelago, where direct anthropogenic stressors are extremely limited. Here, we present the results of the first quantitative survey of coral community structure across habitats and depths around the island. Despite its geographical isolation in the depauperate South Central Pacific, its small size and unfavourable environmental conditions (competition with macroalgae, low sea surface temperatures, reduced reef accretion), the diversity of scleractinian corals at Rapa is particularly high (112 species from 32 genera, including 37 species of Acropora) in comparison to other French Polynesian islands and subtropical Pacific locations. Our results indicate that the abundance (>100 colonies per 10 m2 recorded at nine of the 17 sampling stations) and cover (>40% at four stations) of corals are relatively high for a marginal reef location. Strong spatial heterogeneity was found, with high variation in diversity, abundance, cover and community composition among stations. Variation in community composition was related to habitat types, with distinct assemblages among fringing reefs within bays, reef formations at bay entrances, and those on the submerged platform surrounding the island. On the platform, a depth gradient was detected, with generic richness, abundance and cover generally greater at deeper stations (18-20 m depth) compared with medium-depth (10-12 m) and shallow (1-3 m) stations. A gradient was also recorded along bays, with increasing coral diversity and abundance from the bay heads to the bay entrances. The coral community at Rapa was characterized by the presence of several taxa not found in other French Polynesian archipelagos and the rarity of others that are common and abundant in the Society and the Tuamotu islands. Another distinctive feature of reef communities at Rapa is the high cover and dominance of macroalgae, particularly in the shallower parts of the surrounding platform, which probably explains the lower densities of coral colonies recorded there. These characteristics of the diversity and biogeographical composition of coral assemblages at Rapa provide considerable ecological grounds for its conservation. [ABSTRACT FROM AUTHOR]

The study of complete mitochondrial genomes (mitogenomes) revealed different gene rearrangements, highly variable markers, and delineated clades that have aided the understanding of the evolutionary history in corals. In this study, we examined mitogenomic variation of reef-building Porites corals and designed 34 primer pairs to target high diversity regions and to amplify the complete mitogenome of a widely-distributed Indo-Pacific species of Porites ( P. lobata) and two endemic species of the Eastern Pacific ( P. sverdrupi and P. panamensis). All primer pairs amplified for each species and the mitogenomes assembled yielded the same gene order as obtained from next-generation sequencing. Mitogenomic variation in Porites corals was three to ten times higher than in Acropora or Pocillopora, two other major reef builders. In contrast to these corals, the nucleotide variation in Porites species was distributed evenly along the mitogenome. Primers designed here are useful to amplify regions with the highest variation possible as well as to assemble the whole mitogenomes of different Porites species. The resulting mitogenomes should improve our understanding of evolutionary relationships, delimitation of species, and conservation within the genus Porites. [ABSTRACT FROM AUTHOR]

We report here an interannual survey (2006–2012) of coral cover in the northwestern lagoon of New Caledonia, to assess the impact of an important dredging operation (August 2008–February 2010) associated with the construction of the largest nickel mining site in the Pacific. A BACI (Before-After Control-Impact) analysis failed to detect any significant interaction between period (before, during, and after dredging) and the category of the stations (impact vs. control). Among the 31 stations surveyed, only seven showed decreasing coral cover during the study period, mainly due to a decline in Acroporidae. However, the relationship between the dredging and this decrease was highly plausible only for one station, situated 0.9 km from the dredging site. High hydrodynamism in the study area, the abundance of resistant corals and efficient protective measures during the dredging operation might explain these localised and limited impacts. [ABSTRACT FROM AUTHOR]

During diagenetic stages, the aragonitic skeletons and the inter/intra-corallite cement of the upper Jurassic corals of Hanifa Formation either dissolved or subjected to diagenetic alterations including cementation, micritization, recrystallization, silicification, dolomitization and dedolomitization. The proposed sequence of diagenetic stages is as follows: early marine diagenesis, early meteoric and mixing zone diagenesis, late meteoric diagenesis, and shallow burial diagenesis. Each stage is characterized by certain diagenetic processes. The source of sulfate solutions for dedolomitization in the studied corals is the dissolved anhydrite deposits of the Arab-Hith Formations, sometime before their erosion. A possible source of silica, needed for the formation of chert and chalcedony, is the sponge spicules dispersed in many carbonates of the Hanifa Formation. [ABSTRACT FROM AUTHOR]

Of all reef-building coral species, 80-85 % initially draw their intracellular symbionts (dinoflagellates of the genus Symbiodinium) from the environment. Although Symbiodinium cells are crucial for the growth of corals and the formation of coral reefs, little is known about how corals first encounter free-living Symbiodinium cells. We report how the supply of free-living Symbiodinium cells to the benthos by adult corals can increase the rate of horizontal symbiont acquisition for conspecific recruits. Three species of newly settled aposymbiotic (i.e., symbiont-free) corals were maintained in an open aquarium system containing: sterilized sediment and adult coral fragments combined; adult coral fragments alone; sterilized sediment alone; or seawater at Heron Island, Great Barrier Reef, Australia. In all instances, the combination of an adult coral and sediment resulted in the highest symbiont acquisition rates by juvenile corals (up to five-fold greater than seawater alone). Juvenile corals exposed to individual treatments of adult coral or sediment produced an intermediate acquisition response (<52 % of recruits), and symbiont acquisition from unfiltered seawater was comparatively low (<20 % of recruits). Additionally, benthic free-living Symbiodinium cells reached their highest densities in the adult coral + sediment treatment (up to 1.2 × 10 cells mL). Our results suggest that corals seed microhabitats with free-living Symbiodinium cells suitable for many coral species during the process of coral recruitment. [ABSTRACT FROM AUTHOR]

Coral reefs are the most diverse marine ecosystems. However, coral cover has decreased worldwide due to natural disturbances, climate change, and local anthropogenic drivers. In recent decades, various genetic methods and molecular markers have been developed to assess genetic diversity, structure, and connectivity in different coral species to determine the vulnerability of their populations. This review aims to identify population genetic studies of scleractinian corals in the last decade (2010–2020), and the techniques and molecular markers used. Bibliometric analysis was conducted to identify journals and authors working in this field. We then calculated the number of genetic studies by species and ecoregion based on data obtained from 178 studies found in Scopus and Web of Science. Coral Reefs and Molecular Ecology were the main journals published population genetics studies, and microsatellites are the most widely used molecular markers. The Caribbean, Australian Barrier Reef, and South Kuroshio in Japan are among the ecoregions with the most population genetics data. In contrast, we found limited information about the Coral Triangle, a region with the highest biodiversity and key to coral reef conservation. Notably, only 117 (out of 1500 described) scleractinian coral species have genetic studies. This review emphasizes which coral species have been studied and highlights remaining gaps and locations where such data is critical for coral conservation. • Microsatellites are the most widely used markers in the study of genetic populations in scleractinian corals. • In spite of 1500 species of scleractinian corals, only 117 species have been studied for population genetics. • The two most studied ecoregions are those included in the Caribbean Sea and the Great Barrier Reef. • The most studied species are those of the genus Acropora and Pocillopora. [ABSTRACT FROM AUTHOR]

The number of studies on coral reproduction has increased worldwide; nevertheless, in Colombia only few studies have been conducted, and none from the area of the present study. Colonies of the scleractinian coral species Orbicella annularis, Pseudodiploria strigosa, and Siderastrea siderea were sampled in Isla Fuerte (Bolívar), Colombia, in order to evaluate their gametogenesis and fecundity. Samples were taken from the center and the edge of 3-5 colonies of each species between August and September 2011, and between April and June 2012. Samples were fixed in 10% formaldehyde solution; later, they were decalcified using 10% HCl. Finally, they were conserved in 70% ethanol. Fecundity was calculated by direct observation, and the different stages of development were identified with histological techniques using Toluidin blue stain. Oocytes or spermaries were not found in any samples during stage I. Oocytes from O. annularis were found during July (stages II and III), and August (II-IV), whereas, oocytes from P. strigosa were found during April (II), and July (II-IV). Oocytes from S. siderea were found in all samples. Spermaries from O. annularis were found only during August. Spermaries from P. strigosa were found during April (II and III), and July (II-IV); and from S. siderea during August (II-IV), and September (II-V). O. annularis presented 394,6 oocyte/cm² in the center and 20,1 oocyte/cm² in the edge during July; whereas P. strigosa presented 368,8 oocyte/cm² in the center during April. In spite of the differences in oocytes between the center and edge of the colonies, in this study the values found were higher than those for other Colombian Caribbean reefs under degradation conditions, such as other sites where fecundity was between 11 and 100 oocyte/ cm², respectively. These results allow us to observe and conclude that this reef is in better condition compared to two other Caribbean reefs studied. We recommend an annual monitoring of these and other scleractinian coral species in the Colombian Caribbean. [ABSTRACT FROM AUTHOR]

The symbiosis between corals and dinoflagellates promotes the rapid growth of corals in shallow tropical oceans, and the high overall productivity of coral reefs. The aim of this study was to quantify and understand variation in carbon acquisition and allocation among coral species. We measured multiple physiological traits (including symbiont density, calcification, photosynthesis and tissue composition) for the same coral fragments to facilitate direct comparisons between species (Stylophora pistillata, Pocillopora damicornis, Galaxea fascicularis, Turbinaria reniformis and Acropora sp.). Tissue protein content was highly sensitive to the availability of particulate food, increasing in fed colonies of all species. Despite among-species variation in physiology, and consistent effects of feeding on some traits, overall energy allocation to tissue compared with skeleton growth did not depend on food availability. Extrapolating from our results, estimated whole-assemblage carbon uptake varied >20-fold across different coral assemblages, but this variation was largely driven by differences in the tissue surface area of different colony morphologies, rather than by differences in surface-area-specific physiological rates. Our results caution against drawing conclusions about reef productivity based solely on physiological rates measured per unit tissue surface area. Understanding the causes and consequences of among-species variation in physiological energetics provides insight into the mechanisms that underlie the fluxes of organic matter within reefs, and between reefs and the open ocean. [ABSTRACT FROM AUTHOR]

We report variation in the size-structure of three coral taxa in the Society Islands (French Polynesia) using a hierarchical sampling design that integrates the regional (among three islands: Moorea, Raiatea, Tahiti), island (among three locations around each island), and local levels (among three depths: 6, 12, 18 m, at each location). All coral taxa exhibited strong heterogeneity in their size-structure, with marked variation among depths, locations, and islands. Porites spp. and Acropora globiceps populations at 6 m depth were dominated by smaller size classes compared to other depths. Regional-scale variation was particularly evident for Pocillopora meandrina and A. globiceps , with a higher proportion of smaller colonies found at Raiatea, probably as a result of recent cyclones followed by higher recruitment rates. Porites spp. populations were characterized by a preponderance of larger colonies, and greater size ranges compared to the other two taxa. [ABSTRACT FROM AUTHOR]

As anthropogenic climate change is an ongoing concern, scientific investigations on its impacts on coral reefs are increasing. Although impacts of combined ocean acidification (OA) and temperature stress (T) on reef-building scleractinian corals have been studied at the genus, species and population levels, there are little data available on how individual corals respond to combined OA and anomalous temperatures. In this study, we exposed individual colonies of Acropora digitifera , Montipora digitata and Porites cylindrica to four p CO 2 -temperature treatments including 400 μatm-28 °C, 400 μatm-31 °C, 1000 μatm-28 °C and 1000 μatm-31 °C for 26 days. Physiological parameters including calcification, protein content, maximum photosynthetic efficiency, Symbiodinium density, and chlorophyll content along with Symbiodinium type of each colony were examined. Along with intercolonial responses, responses of individual colonies versus pooled data to the treatments were investigated. The main results were: 1) responses to either OA or T or their combination were different between individual colonies when considering physiological functions; 2) tolerance to either OA or T was not synonymous with tolerance to the other parameter; 3) tolerance to both OA and T did not necessarily lead to tolerance of OA and T combined (OAT) at the same time; 4) OAT had negative, positive or no impacts on physiological functions of coral colonies; and 5) pooled data were not representative of responses of all individual colonies. Indeed, the pooled data obscured actual responses of individual colonies or presented a response that was not observed in any individual. From the results of this study we recommend improving experimental designs of studies investigating physiological responses of corals to climate change by complementing them with colony-specific examinations. [ABSTRACT FROM AUTHOR]

Coral reefs are important coastal ecosystems for both humans and marine species due to the diversity of ecosystem services they provide. Unfortunately, and as a consequence of anthropogenic and natural factors these ecosystems are disappearing. To mitigate coral reef degradation and potential loss, several active and passive conservation strategies have been implemented. Active strategies imply the direct intervention of humans in the ecosystem. Ecological restoration (ER) is an active strategy recently used in marine ecosystems. However, since the 1980s, different methodologies have been designed and implemented to mitigate threats and recover degraded coral reefs. Currently, although still under development, the most used ER methodologies on coral reefs are coral rearing through asexual and sexual propagation, and double restoration. This paper presents a general description of coral reef ER. It begins with characteristics of reef building corals ER methods and experiences, and ends with recommendations for those who want to develop and implement ER processes on coral reefs. [ABSTRACT FROM AUTHOR]

Coral habitat structures increase abundance and richness of organisms by providing niches, easy access to resources and refuge from predators. Corals harbor a great variety of animals; the variation in coral species morphology contributes to the heterogeneity and complexity of habitat types. In this report, we studied the richness and abundance of crustaceans (Decapoda, Copepoda, Peracarida and Ostracoda) associated with three species of Mussismilia exhibiting different growth morphologies, in two different coral reefs of the Bahia state (Caramuanas and Boipeba-Moreré, Brazil). Mussismilia hispida is a massive coral; M. braziliensis also has a massive growth pattern, but forms a crevice in the basal area of the corallum; M. harttii has a meandroid pattern. PERMANOVA analysis suggests significant differences in associated fauna richness among Mussismilia species, with higher values for M. harttii, followed by M. braziliensis and later by M. hispida. The same trend was observed for density, except that the comparison of M. braziliensis and M. hispida did not show differences. Redundancy and canonical correspondence analysis indicated that almost all of the crustacean species were more associated with the M. harttii colonies that formed a group clearly separated from colonies of M. braziliensis and M. hispida. We also found that the internal volume of interpolyp space, only present in M. harttii, was the most important factor influencing richness and abundance of all analyzed orders of crustaceans. [ABSTRACT FROM AUTHOR]

Colombian Caribbean reefs have deteriorated significantly over the last three decades. Coral recruitment is an important demographic process that determines the replenishment of populations and the natural potential for recovery of reef ecosystems after perturbations. We studied the composition and abundance of juvenile corals on a fringing reef (Little Reef) off San Andres Island, Colombia, using 1 m2quadrats (N= 33) spread randomly on the reef. We surveyed a total of 190 juvenile corals belonging to seven families and 15 species, with a total density of 5.75 ± 3.47 (mean ± SD) juveniles m−2. The population of juvenile corals was dominated by species of the generaFavia,AgariciaandPorites(85.8%), while the adult population was dominated byDiploria,AcroporaandOrbicella(78.4%). Most (71.6%) juveniles were between 1.1 and 2.0 cm. The most abundant species wasFavia fragum(67 individuals), whileAgaricia agariciteswas the most frequently occurring (26.9%), covering the highest percentage (76.9%) of the substrate and having the largest Importance Value Index (44.6%). The community of juvenile corals on Little Reef was dominated by species that brood planulae while the adult community was dominated by species that spawn gametes. Furthermore, the two most abundant juvenile coral species had negatively skewed size–frequency distributions, indicating low recent recruitment. This study provides a demographic baseline for monitoring future changes in recruitment patterns. [ABSTRACT FROM PUBLISHER]

Pollution by heavy metals remains today an important threat to the health of humans and ecosystems, but there is still a paucity of data on the response of early life stages of key organisms. In this context, the present work assessed the fertilization success rate of two Acropora species ( A. cytherea and A. pulchra ) from the French Polynesia reefs exposed to six increasing copper concentrations in seawater. The two species showed a relatively high tolerance to copper (4h30-EC 50 was 69.4 ± 4.8 μg L −1 and 75.4 ± 6.4 μg L −1 for A. cytherea and A. pulchra, respectively). As Cu concentration increases, an increasing proportion of deformed embryos was recorded (67.6% and 58.5% for A. cytherea and A. pulchra , respectively, at 220 μg Cu L −1 ). These results demonstrated thus, that high levels of copper could negatively impair the normal fertilization process of coral gametes and therefore alter the renewal of coral populations. Since the two Acropora species investigated in this study displayed a high resistance to copper, these results should be considered in the context of multiple stressors associated with climate change, where rising temperature or ocean acidification may significantly exacerbate copper toxicity. [ABSTRACT FROM AUTHOR]

The Berriasian carbonate successions cropping out in the shallow-water platform of the easternmost Prebetic Domain (SE Spain) involve reef-associated environments including a diverse epibiota with diceratid representatives unreported so far. Interpretation of different sub-environments suggests a proximal-distal shallow platform transect. In the shallowest nearshore environment, high energy conditions are recorded, with fine-grained bioclasts interbedded with episodes with black pebbles. Subsequently, a more restricted intra-platform environment is represented by oncoidal rudstones with benthic foraminifera, photophilic microencrusters, microbial-type coatings, mud mounds and a rich record of epibenthic biota preserved in life position (diceratid patches, stromatoporoids, and a diverse coral assemblage). This association points to relatively stable and restrictive low-energy conditions in a proximal shallow-water subtidal environment below the fair-weather wave base. Distally, a deeper, opener setting is established. Here, phaceloid and thin-laminated corals are preserved in life position in a calpionellid-rich matrix typifying a mesophotic reefal complex with clear open marine influence. Biostratigraphical analysis performed mainly on benthic foraminifera, algae, diceratids, and coral representatives allows to specify a Berriasian age for these facies. New occurrence data are also reported, such as the oldest record of the coral genus Floriastrea worldwide. The highly diverse coral assemblages reveal a species-level taxonomic divergence in relation with taxa from the same biochore and palaeogeographical domain, supporting the endemic condition for this fauna. The first report of diceratids in the Eastern Prebetic around the J/C transition evokes Heterodiceras as possible precursor of the Cretaceous rudist build-ups developed in the Urgonian platforms in the Prebetic Domain. [Display omitted] • Berriasian reefal habitats from the Betic Range are described for the first time. • Epibenthic biota reveals a deepening transect (nearshore to open sea environments). • Berriasian diceratids are recorded for the first time in the South-Iberian margins. • Earliest occurrence data of the genus Floriastrea worldwide is settled. • The biogeographical endemic condition is inferred from the coral and rudist faunas. [ABSTRACT FROM AUTHOR]

The aulastraeoporid coral Preverastraeopsis gen. n.represented by one species Phyllocoenia major Hackemesser, 1936 from the Cenomanian (?Aptian-Cenomanian) of Central Greece is described. The new genus, characterized by astreoid colony structure is not known to date in the family Aulastraeoidae Alloiteau. The genus is related to Preverastraea Beauvais, which differs from Preverastraeopsis by cerioid colony with corallite wall in structural continuation with the septa.In the latter the radial elements are of costo-septal type, free in their external ends.

Eighteen scleractinian coral species belonging to 13 genera, 8 families and 4 suborders have been identified from the lower and upper parts of the Upper Jurassic (Oxfordian) Hanifa Formation at Jabal Al-Abakkayn, central Saudi Arabia.Actinastrea bernensis,A. crassoramosa,Coenastraea hyatti,Stylina kachensis,Cryptocoenia slovenica,C. wegeneri,Isastrea hemisphaerica,I. bernensis,Montlivaltia cornutiformis,M. frustriformis,Collignonastraea jumarensis,Ovalastrea micheliniandVallimeandropsis davidsoniare believed to be recorded for the first time from the Jurassic rocks of central Arabia. Most corals have massive hemispherical and globular forms, and few corals have dendroid and conical growth forms. They occur as small, isolated patches, about 0.5 m thick and about 10–30 m wide, in argillaceous reefal limestones. The identified corals show Africa, north America, northern, southern and western Europe, and southern or eastern Asia corals. The low diversity and abundance as well as the small size of colonies are attributed to inimical palaeoecological factors throughout the reefoids formation such as muddy substratum, water turbidity, high rate of sedimentation. [ABSTRACT FROM AUTHOR]

Three species of cryptochirid crabs, obligatory symbionts of scleractinian corals, have so far been recorded from Brazil:Troglocarcinus corallicola,Opecarcinus hypostegusandKroppcarcinus siderastreicola. All three genera are monospecific. Individuals belonging to an undescribed species ofTroglocarcinus, here described asT. hirsutussp. nov., were found associated with colonies ofMussismiliafrom Bahia State, northeastern region of Brazil. The new species is distinguished from its congener mainly by a carapace with several large spines delimiting the protogastric and mesogastric regions, sternite of first pereopod with setae and third pleopod of female being uniramous or biramous. An emendation to the diagnosis of the monospecificTroglocarcinusis proposed. http://zoobank.org/urn:lsid:zoobank.org:pub:0FA03021-69A6-4F93-AA0A-6451BC6D2DE4 [ABSTRACT FROM AUTHOR]

Understanding the natural variability of the Earth’s climate system and accurately identifying potential anthropogenic influences requires long term, geographically distributed records of key climate indicators, such as temperature and precipitation that extend prior to the last 400 years of the Holocene. Reef corals provide an excellent source of high resolution climate records, and importantly represent the tropical marine environment where palaeoclimate data are urgently required. Recent decades have seen significant improvement in our understanding of coral biomineralisation, the associated uptake of geochemical proxies and methods of identifying and understanding the effects of both early and late, post depositional diagenetic alteration. These processes all have significant implications for interpreting geochemical proxies relevant to palaeoclimatic reconstructions. This paper reviews the current ‘state of the art’ in terms of coral based palaeoclimate reconstructions and highlights a key remaining problem. The majority of coral based palaeoclimate research has been derived from massive colonies of Porites . However, massive Porites are not globally abundant and may not provide material of a particular age of interest in those regions where they are present. Therefore, there is great potential for alternate coral genera to act as complimentary climate archives. While it remains critical to consider five key factors – vital effects, differential growth morphologies, geochemical heterogeneity in the skeletal ultrastructure, transfer equation selection and diagenetic screening of skeletal material – in order to allow the highest level of accuracy in coral palaeoclimate reconstructions, it is also important to develop alternate taxa for palaeoclimate studies in regions where Porites colonies are absent or rare. Currently as many as nine genera other than Porites have proven at least limited utility in palaeothermometry, most of which are found in the Atlantic/Caribbean region where massive Porites do not exist. Even branching taxa such as Acropora have significant potential to preserve environmental archives. Increasing this capability will greatly expand the number of potential geochemical archives available for longer term temporal records of palaeoclimate. [ABSTRACT FROM AUTHOR]