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

Background: Coral diseases are one of the serious threats embroiling in the imbalance of the coral holobiont integrity through disruption of the complex symbiotic relationship between endobiotic alga, coral animal, and a group of microorganisms. Such diseases are usually associated with many bacterial pathogens inflicting gross lesions in corals which show resistance against antibiotics. Therefore, this has led scientists to draw more attention towards the curative compounds from natural resources like herbal plants and seaweeds as substitutes for chemical antimicrobial agents. This study aimed to evaluate the antibacterial activity of the crude extracts (n-hexane, ethyl acetate, and ethanol), alkaloids, and flavonoids from Sargassum fusiforme through Well Diffusion Assay against different isolated bacterial coral pathogens such as (Vibrio owensii, Empedobacter brevis, Providencia vermicola, and Brevibacterium linens) which cause white band disease to coral reef Porites lutea. This study was also validated by bacterial growth kinetics using optical density, dry weight, and plate count method for the isolated coral bacterial pathogens. Results: The results indicated that the crude extract with n-hexane and alkaloid extract showed prominent inhibiting activity against the tested bacterial pathogens compared to other extracts. Conclusions: Here we report S. fusiforme extracts as a novel antibacterial agent against four Porites lutea bacterial pathogens and further investigation is recommended against other coral pathogens. Overall, S. fusiforme extracts might be able to improve the health status of commercially important coral species. [ABSTRACT FROM AUTHOR]

Global climate change and anthropogenic disturbance have significantly degraded biodiversity in coral reef ecosystems. The genetic potential and adaptability of corals are key factors used to predict the fate of global coral reefs under climate change. In this study, we used eight microsatellite loci to study the patterns of reproduction, genetic diversity, and genetic structure of 302 Porites lutea samples across 13° latitudes in the South China Sea (8.8644°N–22.6117°N). The results indicated that P. lutea reproduces largely via sexual reproduction on scales of 5 m and greater and has abundant gene diversity. Additionally, the tropical populations harbored high genetic diversity (based on alleles, effective number of alleles, gene diversity, and heterozygosity). In contrast, genetic diversity was lower in subtropical coral populations. Genetic variation values and pairwise FST revealed that tropical and subtropical populations had significantly different genetic structures. Finally, the Mantel tests showed that the genetic differentiation and genetic variation of P. lutea were strongly correlated with sea surface temperature and slightly correlated with geographical distance. These results indicated that tropical P. lutea populations have high genetic potential and adaptability because of their sexual reproduction and genetic diversity, giving them a greater capacity to cope with climate change. Subtropical coral populations showed lower genetic diversity and, thus, relatively poor genetic resilience in response to low average sea surface temperature and human activities. Our study provides a theoretical basis for the protection and restoration of coral reefs.

Corals in the genus Porites are among the most dominant scleractinian corals in the coral reef ecosystems yet highly vulnerable to climate change impacts and diseases. In the Kondang Merak and Sempu Strait waters of Indian Ocean, it has been reported that more than 45% of the corals were infected with Pink Line Syndrome (PLS). The objectives of this study are to isolate, morphologically and molecularly characterize, and identify the PLS associated bacteria that infected Porites lutea coral. The sampling was performed at the Kondang Merak waters in June 2018 by snorkeling during low tide. In order to isolate and purify the dominant bacterial colony, quadrants streak-plating technique was performed using ZoBell marine agar culture media. 16S rRNA sequencing and BLAST homology were performed for the molecular identification of the bacterial colony. Results showed that the bacterial colony associated with PLS was of Bacillus cereus, which was closely related to Bacillus pseudomycoides, Bacillus toyonensis and Bacillus thuringensis with 97% similarity. The occurrence of B. cereus bacterium in the PLS infected P. lutea demonstrated that this opportunistic pathogen might be responsible for the PLS in the P. lutea coral. [ABSTRACT FROM AUTHOR]

Bell, T.; Lander, M.A.; Jenson, J.W.; Randall, R.H.; Partin, J.W., and Prouty, N.G., 2019. A 50-year Sr/Ca time series from an enclosed, shallow-water Guam coral: In situ monitoring and extraction of a temperature trend, annual cycle, and ENSO and PDO signals. Journal of Coastal Research, 35(2), 269–286. Coconut Creek (Florida), ISSN 0749-0208. Located on the northern edge of the West Pacific Warm Pool and having a developed economy and modern infrastructure, Guam is well positioned and equipped for obtaining natural records of the west Pacific maritime paleoclimate. This study was a proof of concept to explore whether useful climate proxy records might be obtained from coral at readily accessible, even if geochemically nonoptimal, coastal sites. A 50-year Sr/Ca record (1960–2010) was thus obtained from a shallow-water, near-shore Porites lutea colony at a recreational facility inside Guam's Apra Harbor and compared with local and regional meteorological records, including the El Niño–Southern Oscillation (ENSO) and Pacific Decadal Oscillation (PDO) indices. The accessibility of the site enabled documentation of relevant environmental variables for 16 months (September 2009–December 2010): seawater δ18O, pH, seawater cations, and nitrate. Time series of seawater δ18O, pH, and cations show evidence of freshwater input from direct rainfall and stream discharge into the harbor. An anomalously higher mean and variable concentrations of Ba suggest the presence of river-borne, fine-grained terrigenous sediment. Nevertheless, the Sr/Ca time series reproduces a long-term warming trend seen in historical records of local air temperature and regional sea-surface temperature (SST) and closely tracks the ENSO and PDO indices over the entire 50-year record. The consistency of the results with Guam's historical instrumental records, previous coral δ18O results from Guam obtained by others, and previous Sr/Ca proxy results for SST in similar environments elsewhere demonstrate that accessible near-shore sites—where environmental conditions can be monitored—can produce useful Sr/Ca records of local and regional climate phenomena. [ABSTRACT FROM AUTHOR]

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

Hard coral Porites lutea is an animal that lives on the ocean floor. This species may live for years and accumulate heavy metals from its surrounding environments. The aims of this study was to know accumulation of heavy metals (Pb, Cd, and Cu) pollution by Porites lutea at different islands in Spermonde Archipelago waters. This study used field surveys around Laelae, Bonebatang and Badi Islands of South Sulawesi. Field parameters measured were oceanographic parameters, metals in water and sediment. Hard coral was extracted using nitric acid, then measured its heavy metal levels using Atomic Absorption Spectrophotometer. Several field parameters such as temperature, salinity, turbidity, pH and dissolved oxygen indicated no differences at each location, whereas the difference was observed in the values of Total Suspended Solid and dissolved oxygen. The results showed the accumulation of heavy metals in the skeleton of Porites lutea was Pb>Cu>Cd and Laelae>Bonebatang>Badi Island.

Oil pollution can release trace metals (TMs) with cumulative toxicity into seawater, harming marine ecosystems in the long term. However, the lack of studies has inhibited our understanding of the effects and mechanisms of oil pollution on TMs in seawater. Hence, we investigated the 10-year monthly variation of TMs in Porites coral skeletons from the northern South China Sea (SCS), complemented by spatial distribution of TMs in seawater, sediments and characterization of TMs in fuel oil. The results of principal component-multivariate linear regression showed that the total contribution of oil pollution as a source to TMs in surface seawater was 77.2%, where the residence time of TMs (Ni, V, Cr, Co, Cu, Mn, Fe, and Mo) released from oil spills in surface seawater was approximately 1.4 months. Due to the geochemical nature of the metals, their seasonal variations are controlled by tropical cyclones (Ni, V, Cr, Co, Cu, Mn, Fe, and Mo), winter monsoons (Pb, Cd, Ba, and Zn) and sea surface temperature (Sr). This study shows that coral skeletons can be used as a new tool to study marine oil pollution. This provides valuable reference data for accurately identifying and quantifying the effects of oil pollution on TMs in seawater from a spatial and temporal perspective. [Display omitted] • High-resolution coral skeletons can be used as a novel tool for marine pollution. • Contribution of oil pollution to each trace metal in surface seawater was estimated. • Effects of oil spills on trace metal in surface seawater can last for ∼1.4 months. [ABSTRACT FROM AUTHOR]

A slice from a Porites Lutea coral core collected inside the Enewetak Atoll lagoon, within 15 km of all major nuclear tests conducted at the atoll, was analysed for 236 U, 239 Pu and 240 Pu over the time interval 1952-1964 using a higher time resolution than previously reported for a parallel slice from the same core. In addition two sediment samples from the Koa and Oak craters were analysed. The strong peaks in the concentrations of 236 U and 239 Pu in the testing years are confirmed to be considerably wider than the flushing time of the lagoon. This is likely due to the growth mechanism of the coral. Following the last test in 1958 atom concentrations of both 236 U and 239 Pu decreased from their peak values by more than 95% and showed a seasonal signal thereafter. Between 1959 and 1964 the weighted average of the 240 Pu/ 239 Pu atom ratio is 0.124 ± 0.008 which is similar to that in the lagoon sediments (0.129 ± 0.006) but quite distinct from the global fallout value of ∼0.18. This, and the high 239,240 Pu and 236 U concentrations in the sediments, provides clear evidence that the post-testing signal in the coral is dominated by remobilisation of the isotopes from the lagoon sediments rather than from global fallout. [ABSTRACT FROM AUTHOR]

Corals evolved by establishing symbiotic relationships with various microorganisms (the zooxanthellae, filamentous algae, cyanobacteria, bacteria, archaea, fungi and viruses), forming the ‘coral holobiont'. Among them, the endolithic community is the least studied. Its main function was considered to be translocation of photo-assimilates to the coral host, particularly during bleaching. Here, we hypothesize that (i) endolithic algae may show similar primary production rates in healthy or bleached corals by changing their pigment ratios, and therefore that similar production and translocation of organic matter may occur at both conditions and (ii) diazotrophs are components of the endolithic community; therefore, N2 fixation and translocation of organic nitrogen may occur. We tested these hypotheses in incubation of Porites lutea with 13C and 15N tracers to measure primary production and N2 fixation in coral tissues and endoliths. Assimilation of the 13C atom (%) was observed in healthy and bleached corals when the tracer was injected in the endolithic band, showing translocation in both conditions. N2 fixation was found in coral tissues and endolithic communities with translocation of organic nitrogen. Thus, the endolithic community plays an important role in supporting the C and N metabolism of the holobiont, which may be crucial under changing environmental conditions.

The marine ecosystem contains a solution for food, shelter, pharmaceutical problems and has a key role in the economy of the country as tourism. The Gulf of Kachchh, known for its high tides and the coral reefs are less explored for its antibiotic activity due to the coral bleaching and diseases. The bacterial strains in the coral Porites lutea are determined to possess antibiotic activity against bacterial strains such as E.coli, P. aeruginosa, S. aureus and S. faecalis. Among thirty bacterial strains isolated from the tissue, skeleton and mucus, two bacterial strains resulted in the better antagonistic activity. The antibiotic compound extracted from both the bacteria elucidated to be 4-[(2E)-4-hydroxypent-2-en-1-yl]-5,6-dihydro-2H-pyran-2-one. Further, through ADMET prediction it was inferred that it is an effective drug lead as it reports less toxicity and better drug-likeliness. The study also includes the effect of Poly Hydroxy Butarate (PHB) production by the isolated bacterial strain. • Corals have mutualistic bacterial species on its surface which produce various antibacterial compounds. • Among 30 bacterial strains two strains produced better antibacterial activity. • Antibiotic compound extracted from both the bacteria elucidated to be 4‐[(2E)‐4‐hydroxypent‐2‐en‐1‐yl]‐5,6‐dihydro‐2H‐pyran‐2‐one. • The docking studies revealed the binding ability of the extracted antibacterial compound. [ABSTRACT FROM AUTHOR]

Actinobacteria is a ubiquitous major group in coral holobiont. The diversity and spatial and temporal distribution of actinobacteria have been rarely documented. In this study, diversity of actinobacteria associated with mucus, tissue and skeleton of Porites lutea and in the surrounding seawater were examined every three months for 1 year on Luhuitou fringing reef. The population structures of the P. lutea-associated actinobacteria were analyzed using phylogenetic analysis of 16S rRNA gene clone libraries, which demonstrated highly diverse actinobacteria profiles in P. lutea. A total of twenty-five described families and ten unnamed families were determined in the populations, and 12 genera were firstly detected in corals. The Actinobacteria diversity was significantly different between the P. lutea and the surrounding seawater. Only 10 OTUs were shared by the seawater and coral samples. Redundancy and hierarchical cluster analyses were performed to analyze the correlation between the variations of actinobacteria population within the divergent compartments of P. lutea, seasonal changes, and environmental factors. The actinobacteria communities in the same coral compartment tended to cluster together. Even so, an extremely small fraction of OTUs was common in all three P. lutea compartments. Analysis of the relationship between actinobacteria assemblages and the environmental parameters showed that several genera were closely related to specific environmental factors. This study highlights that coral-associated actinobacteria populations are highly diverse, and spatially structured within P. lutea, and they are distinct from which in the ambient seawater.

A comprehensive series of nuclear tests were carried out by the United States at Enewetak Atoll in the Marshall Islands, especially between 1952 and 1958. A Porites Lutea coral that was growing in the Enewetak lagoon within a few km of all of the high-yield tests contains a continuous record of isotopes, which are of interest (e.g. 14 C, 236 U, 239,240 Pu) through the testing period. Prior to the present work, 14 C measurements at ∼2-month resolution had shown pronounced peaks in the Δ 14 C data that coincided with the times at which tests were conducted. Here we report measurements of 236 U and 239,240 Pu on the same coral using accelerator mass spectrometry, and again find prominent peaks in the concentrations of these isotopes that closely follow those in 14 C. Consistent with the 14 C data, the magnitudes of these peaks do not, however, correlate well with the explosive yields of the corresponding tests, indicating that smaller tests probably contributed disproportionately to the debris that fell in the lagoon. Additional information about the different tests can also be obtained from the 236 U/ 239 Pu and 240 Pu/ 239 Pu ratios, which are found to vary dramatically over the testing period. In particular, the first thermonuclear test, Ivy-Mike, has characteristic 236 U/ 239 Pu and 240 Pu/ 239 Pu signatures which are diagnostic of the first arrival of nuclear test material in various archives. [ABSTRACT FROM AUTHOR]

Coral reefs are constantly subjected to multiple stresses like diseases and fish predation, which can profoundly influence the coral microbiome. This study investigated the differences in bacterial community structure of healthy, white syndrome affected and blenny nipped coral colonies of Porites lutea, collected from the coral reefs of Gulf of Kachchh, north-west coast of India. Present study observed that the stressed coral colonies harbored more OTUs and contained higher diversity values compared to healthy corals colonies. Similarly, beta diversity analysis indicated the dissimilarities among the three coral samples analyzed. Though the taxonomy analysis indicated bacterial phyla like Proteobacteria, Firmicutes, Bacteroidetes, and Actinobacteria among the entire coral samples studied, there was a variation in their relative abundances. Huge variations were observed in the relative dominance at the bacterial genera level. About 13phyla and 11 genera was identified in healthy coral. The PBN sample was found to contain Proteobacteria, Cyanobacteria, Verrucomicrobia, and Lentisphaerae as dominant phyla and Endozoicomonas, Dyella, Woeseia, and Winogradskyella as dominant genera. The PWS sample contained Proteobacteria, Lentisphaerae, Spirochaetes, and Tenericutes as dominant phyla and Endozoicomonas, Arcobacter, Sunxiuqinia, and Carboxylicivirgia as dominant genera. Among the healthy samples, sequences belonging to Uncultured Rhodospirillaceae were dominant, while Woeseia and sequences belonging to Uncultured Rhodovibrionaceae were dominant among the blenny nipped white syndrome infected corals. Although any previously established pathogen was not identified, present study revealed the presence of a potentially pathogenic bacterium, Arcobacter, among the diseased corals. It also demonstrated a dynamic microbiome among the Porites lutea colonies on subjecting to various stresses. [ABSTRACT FROM AUTHOR]

For investigating variation of heavy metal concentration in growth bands of coral skeletons, Poriteslutea samples were collected from Ngam Island, Trat province, Thailand. The skeleton samples were cleaned using oxidative and reductive treatments to effectively eliminate detritus and organic materials and were acid-digested. Five heavy metals, cadmium (Cd), chromium (Cr), copper (Cu), lead (Pb), and zinc (Zn), in the growth bands of Porites lutea were analyzed using Flame Atomic Absorption Spectrometry (FAAS) and Graphite Furnace Atomic Absorption Spectrometry (GFAAS). As a result, the range of heavy metals found in coral skeletons (μg g-1 as dry weight) was: Cd (0.01-0.19), Cr (0.28-2.25), Cu (2.40-7.71), Pb (0.18-1.13), and Zn (7.64-15.05). The levels shown in descending order were as follows: Zn > Cu > Cr >Pb> Cd. All metals in this study were found in lower concentration when compared with other studies in a polluted area. This study indicated that Porites lutea a good environmental indicator of marine pollution in Ngam Island, and can be useful for past proxy data.

The Similan Islands (Thailand) in the Andaman Sea are exposed to large amplitude internal waves (LAIW), as evidenced by i.a. abrupt fluctuations in temperature of up to 10°C at supertidal frequencies. Although LAIW have been shown to affect coral composition and framework development in shallow waters, the role of LAIW on coral growth is so far unknown. We carried out a long-term transplant experiment with live nubbins and skeleton slabs of the dominating coral Porites lutea to assess the net growth and bioerosion in LAIW-exposed and LAIW-protected waters. Depth-related, seasonal and interannual differences in LAIW-intensities on the exposed western sides of the islands allowed us to separate the effect of LAIW from other possible factors (e.g. monsoon) affecting the corals. Coral growth and bioerosion were inversely related to LAIW intensity, and positively related to coral framework development. Accretion rates of calcareous fouling organisms on the slabs were negligible compared to bioerosion, reflecting the lack of a true carbonate framework on the exposed W faces of the Similan Islands. Our findings show that LAIW may play an important, yet so far overlooked, role in controlling coral growth in tropical waters. [ABSTRACT FROM AUTHOR]

Large amplitude internal waves (LAIW) cause frequent and severe changes in the physico-chemical environment of Andaman Sea coral reefs and are a potentially important source of disturbance for corals. To explore the coral response to LAIW, prey capture disposition and photosynthesis were investigated in relation to changes in seawater temperature, pH, flow speed and food availability in LAIW simulation studies under controlled laboratory conditions, using Porites lutea as a model organism. Although food presence stimulated polyp expansion, we found an overriding effect of low temperature (19°C) causing retraction of the coral polyps into their calices, particularly when pH was altered concomitantly. Decreases in pH alone, however, caused the expansion of the polyps. The exposure history of the colonies played a crucial role in coral responses: prior field exposure to LAIW yielded lower retraction levels than in LAIW-inexperienced corals, suggesting acclimatization. Low temperature (19°C) exposure did not seem to influence the photosynthetic performance, but LAIW-experienced corals showed higher values of maximum dark-adapted quantum yield (Fv/Fm) of photosystem II than LAIW-inexperienced controls. Collectively, these data suggest that P. lutea, the dominant hermatypic coral in the Andaman Sea, can acclimatize to extreme changes in its abiotic environment by modulating its mixotrophic nutrition, through polyp expansion and potential feeding, as well as its photosynthetic efficiency. [ABSTRACT FROM AUTHOR]

Coral harbor diverse and specific bacteria play significant roles in coral holobiont function. Bacteria associated with three of the common and phylogenetically divergent reef-building corals in the South China Sea, Porites lutea, Galaxea fascicularis and Acropora millepora, were investigated using 454 barcoded-pyrosequencing. Three colonies of each species were sampled, and 16S rRNA gene libraries were constructed individually. Analysis of pyrosequencing libraries showed that bacterial communities associated with the three coral species were more diverse than previous estimates based on corals from the Caribbean Sea, Indo-Pacific reefs and the Red Sea. Three candidate phyla, including BRC1, OD1 and SR1, were found for the first time in corals. Bacterial communities were separated into three groups: P. lutea and G. fascicular, A. millepora and seawater. P. lutea and G. fascicular displayed more similar bacterial communities, and bacterial communities associated with A. millepora differed from the other two coral species. The three coral species shared only 22 OTUs, which were distributed in Alphaproteobacteria, Deltaproteobacteria, Gammaproteobacteria, Chloroflexi, Actinobacteria, Acidobacteria and an unclassified bacterial group. The composition of bacterial communities within each colony of each coral species also showed variation. The relatively small common and large specific bacterial communities in these corals implies that bacterial associations may be structured by multiple factors at different scales and that corals may associate with microbes in terms of similar function, rather than identical species. [ABSTRACT FROM AUTHOR]

Coral harbor diverse and specific bacteria play significant roles in coral holobiont function. Bacteria associated with three of the common and phylogenetically divergent reef-building corals in the South China Sea, Porites lutea, Galaxea fascicularis and Acropora millepora, were investigated using 454 barcoded-pyrosequencing. Three colonies of each species were sampled, and 16S rRNA gene libraries were constructed individually. Analysis of pyrosequencing libraries showed that bacterial communities associated with the three coral species were more diverse than previous estimates based on corals from the Caribbean Sea, Indo-Pacific reefs and the Red Sea. Three candidate phyla, including BRC1, OD1 and SR1, were found for the first time in corals. Bacterial communities were separated into three groups: P. lutea and G. fascicular, A. millepora and seawater. P. lutea and G. fascicular displayed more similar bacterial communities, and bacterial communities associated with A. millepora differed from the other two coral species. The three coral species shared only 22 OTUs, which were distributed in Alphaproteobacteria, Deltaproteobacteria, Gammaproteobacteria, Chloroflexi, Actinobacteria, Acidobacteria and an unclassified bacterial group. The composition of bacterial communities within each colony of each coral species also showed variation. The relatively small common and large specific bacterial communities in these corals implies that bacterial associations may be structured by multiple factors at different scales and that corals may associate with microbes in terms of similar function, rather than identical species. [ABSTRACT FROM AUTHOR]

The Luhuitou coral reef is a fringing reef at Hainan Island in the northern South China Sea. Since the 1960s, the reef has experienced several significant ecological changes. During that interval, the mean coral cover decreased dramatically from 80-90% in 1962-65 and to just 12% in 2009. In the 1960s, the coral community structure was divided into three well-defined zones; a Goniastrea zone and Montipora zone (both on the reef flat) and an Acropora zone (on the reef slope). However, by 2009, Porites lutea became the dominant species on the reef flat, whereas the predominance of Acropora on the reef slope weakened significantly. There are few long-established Porites lutea colonies present, with approximately 80% being younger than 30 years old. This demographic pattern differs significantly from healthy coral reefs, which are typically dominated by large, well-established (and mature) coral colonies. The long-term decline of the Luhuitou coral reef has most likely been driven as a result of anthropogenic activities, such as overfishing, destructive fishing, reef rock digging, and mariculture and tourism activities. Our study reinforces previous works and highlights the vulnerability of coral reefs to anthropogenic impacts. [ABSTRACT FROM AUTHOR]

Confocal Raman microscopy mapping was used to investigate the organic matrix distribution within the skeleton of the coral Porites lutea. Two types of growth lines could be identified: one corresponds to the well-known incremental growth layers, whereas the second type of growth lines showed an elemental composition that differed from the incremental growth layers. The position and shape of the latter growth lines resemble either denticle finger-like structures (most likely traces of former spines) or former skeletal surfaces.We hypothesize that these lines are involved in the three-dimensional arrangement of skeletal elements and represent the outer skeletal surface before another growth cycle of elongation, infilling and thickening of skeletal components continues. We show that high spatial resolution mapping can significantly improve our understanding of skeletal growth patterns in coral skeletons. [ABSTRACT FROM AUTHOR]

The article provides information on a study which examined variations in polyp morphology of massive coral species Porites lutea, Diploastrea heliopora, Favia speciosa, and Favia matthaii among sites of differing turbidity within the Wakatobi Marine National Park in Indonesia. All target species except F. speciosa demonstrated increased polyp area with decreased light availability. The role of morphological variability in optimizing environmental suitability is explained.

The article assesses the capacity of the major reef-building coral Porites lutea for repairing partial mortality. The regeneration of artificially induced lesions of standard size in shallow coral reef populations at Réunion Island under different environmental conditions related to seasons and site was examined. Limited capacity for repair in the coral was indicated despite rapid initial lesion regeneration. It was found that the fastest and most complete lesion regeneration occurred during the cooling and cool seasons. It is hypothesized that factors such as chronic stress from organic matter input and run-off from land may further affect corals' regeneration capacity and coral populations' resilience.

Corals harbour diverse microbial communities that can change in composition as the host grows in age and size. Larger and older colonies have been shown to host a higher diversity of microbial taxa and this has been suggested to be a consequence of their more numerous, complex and varied micro-niches available. However, the effects of host age on community structure and diversity of microbial associates remain equivocal in the few studies performed to date. To test this relationship more robustly, we use established techniques to accurately determine coral host age by quantifying annual skeletal banding patterns, and utilise high-throughput sequencing to comprehensively characterise the microbiome of the common reef-building coral, Porites lutea. Our results indicate no clear link between coral age and microbial diversity or richness. Different sites display distinct age-dependent diversity patterns, with more anthropogenically impacted reefs appearing to show a winnowing of microbial diversity with host age, possibly a consequence of corals adapting to degraded environments. Less impacted sites do not show a signature of winnowing, and we observe increases in microbial richness and diversity as the host ages. Furthermore, we demonstrate that corals of a similar age from the same reef can show very different microbial richness and diversity. [ABSTRACT FROM AUTHOR]