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The present study evaluates the antibacterial properties of alkaloids and the crude extracts (ethanol, n-hexane and ethyl acetate) from seaweed Sargassum fusiforme against coral pathogens (Photobacterium galatheae, Vibrio harveyi, Bordetella trematum, and Ochrobactrum pseudogrignonese) isolated from coral Porites lutea. To our knowledge, this is the first in vitro assay for such extracts on Porites lutea coral pathogens. Bacterial pathogens have been identified using 16S RNA and BankIt into gene bank and given the accession numbers (OR401000; OR401001; OR401336, and OR400998 respectively). GC-Mass profiling conducted for n-hexane compounds confirmed the presence of thirty-eight molecules, twelve of which have been previously reported for their bioactivity. The results revealed that alkaloids and n-hexane extract demonstrated eminent antibacterial activity compared to the other extracts against the tested coral pathogenic bacteria. Molecular docking was conducted to evaluate the twelve previously mentioned bioactive molecules to get a full understanding of the interaction of those bioactive molecules on vital bacterial proteins (Hemolysin protein (PDB ID: 1XEZ) and Cytoplasmic proteins (PDB ID: 3TZC)). Docked twelve molecules against hemolysin protein (PDB ID: 1XEZ) came exactly in line with the docked result of the same molecules with cytoplasmic proteins (PDB ID: 3TZC), proving the bioactivity of 6-O-Palmitoyl-L-ascorbic acid, 3TMS derivative; Glycerol monostearate, 2TMS derivative and Eicosanoic acid complexes in antibacterial activity action and score higher than reference ligand. Those three compounds will be investigated separately in future in vitro assay soon. Our conclusions align with the study's antibacterial in vitro assay results. The present study reports the novelty of different extracts of S. fusiforme as an antibacterial agent against coral pathogenic bacteria that trigger diseases in Porites lutea. [ABSTRACT FROM AUTHOR]

In recent decades, vanadium (V) levels in the environment have dramatically increased and will continue to rise alarmingly in the future. Conventional methods for assessing oceanic V typically only involved the collection of seawater and sediments, which significantly limited our understanding of the dynamics of oceanic V and its relationship to environment and climate. Here, the interannual temporal variations in surface seawater V levels in the northern South China Sea, were reconstructed utilizing a 137‐year record of V/Ca ratios from Porites lutea coral from Xiaodonghai Bay off Sanya. We observed that anthropogenic activities had a limited impact on the V levels of surface seawater in the study area, whereas V variability exhibited significant disparities across different time periods. Precipitation‐related submarine groundwater discharge (SGD) recharge was the primary driver of V variation prior to 1990, with tropical cyclones (TCs) playing a detectable role in total precipitation during this period. Conversely, changes in surface seawater V levels after 1990 were predominantly linked to increasingly intense upwelling driven by summer winds. The recharge processes in unconfined groundwater systems within the study area might generate favorable oxic and alkaline conditions, which facilitated mineral dissolution and/or desorption reactions that elevated V concentrations along the groundwater flow path, which were recorded in coral skeletal V/Ca ratios. This study confirmed the seawater V was dominated by SGD and upwelling near Sanya, providing essential evidence for comprehending the geochemical behavior of V and the impact of ocean‐atmospheric climate interactions on long‐term variations in seawater V levels. Plain Language Summary: Recently, the amount of vanadium (V) in our environment has skyrocketed and will only continue to increase. The traditional method of checking oceanic V levels involved collecting seawater and sediment, which provided an incomplete understanding of V behavior in different environments and its relationship to climate change. Therefore, we conducted a detailed study on surface seawater V levels in the northern South China Sea over several years. We observed that human activities had little impact on the surface seawater V levels in our study area, but there were significant variations in V changes across different temporal intervals. Before 1990, precipitation‐induced submarine groundwater discharge was the main cause of changes in V, while tropical cyclones played a minor role in rainfall. However, after 1990, surface seawater V levels were significantly affected by stronger upwelling caused by summer winds. Groundwater systems in the study area may have caused mineral dissolution or desorption reactions, leading to increased V concentrations detected in corals. We looked into where V comes from in surface seawater and what factors affect it, giving us some solid proof on how V behaves chemically and how ocean‐atmospheric climate changes can impact its levels over time. Key Points: Coral vanadium (V)/Ca ratios exhibit a remarkable correlation with submarine groundwater discharge (SGD) prior to 1990Enhanced upwelling activity may modify the relationship between surface seawater V levels and SGDTropical cyclones amplify the impact of SGD on seawater V level by causing heavy precipitation [ABSTRACT FROM AUTHOR]

Global climate change has led to more frequent extreme temperature (extreme heat and cold) events, posing a serious threat to coral reef ecosystems. Higher latitudes are considered potential refuges for reef-building corals, but their response to extreme temperature stress in these regions remain unclear. This study, indoor simulated stress experiments ranging on Porites lutea from Weizhou Island in the northern part of the South China Sea, simulating suitable (26 °C) to extreme high (34 °C) and extreme low (12 °C) temperatures. Physiological, biochemical, and transcriptional responses, were analysed. Results showed P. lutea's tentacles contracted, and symbiotic relationships broke down at both high and low temperatures; leading to oxidative stress, and a higher risk of disease. The coral host's response to temperature stress was positively regulated, mainly through apoptosis and metabolic inhibition pathways, whereas Symbiodiniaceae C15 showed no significant response to either high- or low-temperature stress. The coral host played a dominant role in the holobiont's stress response, using similar mechanisms for both high- and low-temperatures with some differences in the details. This study enhances understanding the temperature response mechanisms of the dominant coral species, P. lutea in the relatively high-latitude regions of the South China Sea., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

As high temperature stress due to climate change threatens tropical corals, cooler areas at relatively high latitudes may be potential refuges. Tolerance to low temperatures is critical in determining whether corals can successfully migrate to higher latitudes. However, the physiological and molecular adaptations that protect corals from low temperature stress are unclear. In this study, scleractinian Porites lutea samples from the tropical Xisha Islands (XS) and subtropical Daya Bay (DY) in the South China Sea were subjected to a reduction in ambient temperature from 26 to 12°C. Differences in physiological changes and gene expression were analysed. P. lutea from both XS and DY exhibited physiological bleaching under low temperature stress, and the Symbiodiniaceae density, Fv/Fm, and chlorophyll-α content were significantly reduced. Symbiosome antioxidative stress and metabolic enzyme activity first increased and then decreased. RNA-seq analysis showed that the host responded to low temperature stress by activating immune, apoptotic, and autophagic pathways and reducing metabolic levels. Nevertheless, Symbiodiniaceae lacked the physiological regulatory capacity to adapt to low temperatures. The lower cold tolerance of XS tropical P. lutea may attribute to lower oxidative stress resistance, lower photosynthetic capacity, worse energy supply, and higher susceptibility to bacterial and viral infections and diseases in XS corals. The difference in cold tolerance may result from genetic differences between the geographic populations and is possibly detrimental to the migration of tropical coral to relatively high latitude refuges. This study provides a theoretical basis for anthropogenically assisted coral migration as a response to global change. [ABSTRACT FROM AUTHOR]

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

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.

Coral-associated microbiomes play important roles in host health and metabolism. It is therefore critical to understand the factors that shape microbiome taxonomic composition and function. Little is known about the stability of coral microbiomes over hourly fluctuations in environmental conditions. For parameters such as temperature and pH, the magnitude of day–night fluctuations can exceed those observed in mean values over seasons, especially on shallow reefs. Such short-term heterogeneity can affect longer term trends, possibly by influencing the extent to which corals acclimate to stress and increase resilience. This study examined diel dynamics of microbiomes (Bacteria and Archaea) in three species of stony coral (Porites lutea, Porites cylindrica, and Pocillopora damicornis) from a shallow reef in Mo'orea (French Polynesia). We assessed microbiome composition and relative transcriptional activity by analyzing 16S rRNA gene and transcript sequences from six timepoints over 48 h for each species. Both the composition and transcription of microbiome members changed significantly over the diel cycle. Most changes did not exhibit clear diel periodicity but were instead stochastic, a pattern potentially influenced also by microspatial variation within a coral colony. However, a subset of taxa, notably the dinoflagellate-associated bacterium Porticoccus and bacteria of the ubiquitous coral-associated Endozoicomonas genus, exhibited cyclic changes in relative frequency over the 2 d sampling period in the DNA dataset of Porites lutea. These patterns raise the possibility that ecological functions of the microbiome may vary substantially over hourly timescales, notably between day and night. Further studies are needed to compare temporal change in the coral microbiome with that due to other factors, such as spatial distance within and among colonies. [ABSTRACT FROM AUTHOR]

A Gram-stain-negative, red pigment-producing, aerobic, and rod-shaped bacterial strain (A2-2 T ) was isolated from a bleached scleractinian coral ( Porites lutea ). Strain A2-2 T grew with 1.0-7.0 % (w/v) NaCl (optimum, 3.0 %), at pH 6.0-11.0 (optimum, pH 8.0), and at 18-41 °C (optimum, 35 °C). Results of phylogenetic analysis based on 16S rRNA gene sequences suggested that strain A2-2 T fell within the genus Spartinivicinus and was closely related to Spartinivicinus ruber S2-4-1H T (98.1 % sequence similarity) and Spartinivicinus marinus SM1973 T (98.0 % sequence similarity). The predominant cellular fatty acids of strain A2-2 T were C 16 : 0 (31.0 %), summed feature 3 (29.0 %), summed feature 8 (11.7 %), C 12 : 0 3-OH (6.4 %), and C 10 : 0 3-OH (5.5 %), while the major respiratory quinone was Q-9. The polar lipids mainly comprised phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, and an unidentified phospholipid. The genome size of strain A2-2 T was 6.8 Mb, with a G+C content of 40.2 mol%. The DNA-DNA hybridization value was 24.2 % between A2-2 T and S. ruber S2-4-1H T and 36.9 % between A2-2 T and S. marinus SM1973 T , while the average nucleotide identity values were 80.1 and 88.8 %, respectively. Based on these findings, strain A2-2 T could be recognized to represent a novel species of the genus Spartinivicinus , for which the name Spartinivicinus poritis sp. nov. is proposed. The type strain is A2-2 T (=MCCC 1K08228 T =KCTC 8323 T ).

An attempt at using laser ablation of biofabricated coralline skeletal material Porites lutea for particle deposition is described. The deposition was performed in an evacuated chamber by pulses of the second harmonic (532 nm) of a Nd:YAG laser. The morphology and the local structure of the deposited films were characterized by scanning electron microscopy, X-ray diffraction, confocal Raman microscopy, and transmission electron microscopy. The as-deposited coatings partially retained the inorganic constituent of the CaCO3 target and mostly transformed to CaO. The crystalline phase was changed from solely aragonite in the target to a mixture of aragonite and calcite microparticles and CaO nanofeatures. © 2004 American Institute of Physics. [ABSTRACT FROM AUTHOR]

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]

Abstract The ratio of barium to calcium in coral skeletons (Ba/Ca coral) is broadly used as a proxy for tracking terrestrial/river runoff. There are, however, inconsistencies in Ba/Ca coral records that have prompted caution in its reliability as an environmental proxy. Direct comparisons between in-situ seawater measurements and coral Ba/Ca are therefore needed to ensure accurate proxy calibration and interpretation. The current study represents the first to test Ba/Ca coral against years-long monthly-resolution contemporaneous measurements of several in-situ seawater parameters i.e. dissolved seawater barium (Ba SW), temperature, salinity, suspended sediments, sedimentation rate and photosynthetically active radiation. We analysed the Ba/Ca coral of six Porites lutea corals sampled from two turbid reefs in Singapore, and explored relationships with in-situ seawater parameters over the period 2008–2015. Our study found poor agreement in Ba/Ca coral from replicate corals sampled from the same reef, and only one of the six colonies analysed showed significant but weak Ba/Ca coral –Ba SW and Ba/Ca coral –Ba/Ca SW relationships. There was also no clear relationship between Ba/Ca coral and skeletal luminescence G/B (a coral proxy strongly linked with salinity and river runoff). This implies that (1) the incorporation of terrestrially derived humic-like substances into the coral is independent of Ba, and (2) it is likely factors other than freshwater discharge/flood events are driving the poor reproducibility of Ba/Ca coral and disconnect with Ba SW at our study sites. We found a positive relationship between Ba/Ca coral and organic suspended solids for 4 of the 6 colonies analysed that suggests biological mechanisms such as feeding could be driving skeletal Ba incorporation. A negative relationship between Ba/Ca coral and total sedimentation rate was also found, suggesting that within reef sediment fluxes may be influencing spatio-temporal variability of the Ba-supply. Ba incorporation into coral skeleton, especially in dynamic, turbid settings such as those found in Singapore, is likely more complex than previously thought. Our results highlight the possibility of high heterogeneity in coral responses to environmental conditions, and the need for careful selection of colonies and a site-specific, replicated approach when attempting to apply Ba/Ca coral as a trace element proxy. [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.

Bacterial diseases affecting corals pose an enormous threat to the health of coral reefs. The relationship between certain bacterial species and coral diseases remain largely unknown. Pigment abnormalities are common in Porites lutea. Here we used Illumina 16S rRNA gene sequencing to analyze the bacterial communities associated with healthy P. lutea and P. lutea with pigment abnormalities. We observed an increase of alpha diversity of the bacterial community of P. lutea with pigment abnormalities, relative to healthy corals. We then identified changes in the abundance of individual operational taxonomic units (OTUs) between pigmented and healthy corals. We were able to identify eight OTUs associated with pigment abnormalities, which are possibly the causative agents of pigment abnormalities. [ABSTRACT FROM AUTHOR]

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]

Coral mucus is one of the key localization in the coral holobiont, as this serves as an energy rich substrate for a wide range of abundant, diverse and multifunctional microbiota. However, very little is known about the functional role of bacterial communities in their associations with corals. In the present study, a total of 48 isolates were obtained from Porites lutea wherein the genus of Bacillus sp. and Vibrio sp. were predominant. Bio-prospecting the coral mucus revealed the existence of (10.42%) antagonistic bacteria against the tested bacterial pathogens. Molecular taxonomy (16S rRNA) proved the identity of these antagonistic bacteria belong to Enterobacter cloacae (CM1), Bacillus subtilis (CM2), Bacillus sp. (CM11) and Bacillus marisflavi (CM12). The secondary screening emphasized that the ethyl acetate extract of B. subtilis showed strong antagonistic effect, followed by the chloroform extract of E. cloacae and ethyl acetate extract of B. marisflavi . The antagonistic activity was statistically confirmed by Principal Component Analysis and Hierarchical Cluster Analysis. The privileged coral mucus associated bacterial (CMAB) solvent extracts inhibited the bacterial pathogens at 100 μg/ml (MIC) and ceased the growth at 200 μg/ml (MBC). The hemolytic and brine shrimp lethality assays disclosed the non-toxic nature of solvent extracts of CMAB. Altogether, the present investigation brought out the diversity of bacteria associated with the mucus of P. lutea . In addition, bio-prospecting corroborated the CMAB as the potential source of pharmacologically important bioactive compounds against a wide range of bacterial pathogens. [ABSTRACT FROM AUTHOR]

Geochemical ratios in coral reef skeletons could be used as proxies to reconstruct past climatological and environmental records in data-poor regions. Using a 103-year data set (1902 to 2005), the annual variations in Ba/Ca and Mn/Ca ratios of Porites lutea skeletons at an eastern offshore area of Hainan Island (19°12´28.4´´N, 110°37´38.8´´E) were analyzed using inductively coupled plasma-optic emission spectrometry (ICP-OES). The analysis results showed that Ba/Ca ratios varied from a minimum of 3.120 μmol mol in 1903 to a maximum of 10.064 μmol mol in 1944, with an average of 5.256 μmol mol. Mn/Ca ratios varied from 0.206 to 5.708 μmol mol with an annual average of 1.234 μmol mol, with peak values in 2001, 1964 and 1932, that correlated with strong rainfall events caused by typhoons. Variation in Ba/Ca and Mn/Ca ratios were compared with available river discharge and precipitation records, providing insight into past climatological events. Human activities and their indirect effects could impact the strength of the relationship between Ba/Ca and Mn/Ca ratios and observed precipitation and terrestrial input in the future. [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]

A Gram-stain-negative, aerobic, rod-shaped, nonmotile and yellow-pigmented bacterium designated E7-10 T was isolated from a bleached scleractinian coral Porites lutea . Strain E7-10 T grew with 1.0-8.0 % (w/v) NaCl (optimum, 4.0 %), at 18-41 °C (optimum, 28 °C) and at pH 6.0-10.0 (optimum, pH 8.0). Phylogenetic analysis using 16S rRNA gene sequences revealed that E7-10 T formed a lineage within the genus Hoeflea , but it was distinct from the closest species ' Hoeflea prorocentri ' PM5-8 T , showing 98.01 % sequence similarity. The predominant cellular fatty acids of E7-10 T were summed feature 8 (26.7 %), C 18 : 1  ω 7 c 11-methyl (26.2 %), C 16 : 0 (20.8 %) and C 19 : 0 cyclo ω 8 c (17.9 %). The major respiratory quinone was Q-10. The polar lipids mainly comprised phosphatidylethanolamine, two glycolipids and five phospholipids. The genome size of E7-10 T was 5.58 Mb with G+C content 60.27 mol%. The digital DNA-DNA hybridization and average nucleotide identity values between the genomes of strains E7-10 T and PM5-8 T were 19.50 and 75.95 %, respectively, which were both below the defined cutoff values (70 % and 95-96 %, respectively) for species delimitation. Thus, strain E7-10 T represents a novel species within the genus Hoeflea , for which the name Hoeflea poritis sp. nov. is proposed. The type strain is E7-10 T (=JCM 35852 T =MCCC 1K08229 T ).

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]

Marginal scleractinian corals growing at their latitudinal limits should be quite sensitive to variations in winter sea surface temperatures (SSTs). An extreme cold event occurring in early 2008 offered a unique opportunity to examine the effect of cold-water anomalies on Porites lutea corals and their physiological tolerance and acclimation in the subtropical northern South China Sea (NSCS). Besides in-situ observation, a subsequent aquarium-based experiment was designed for reproducing the chilling process and a 50-year-long Sr/Ca ratio profile from two P. lutea skeletal slabs was analyzed for reconstructed the historical annual minimum SSTs which ceased Porites calcification. The 2008 low-temperature anomaly caused the minimum daily mean SSTs dropped below 13°C in the Daya Bay. The stress symptoms displayed by local P. lutea colonies included polyp retraction, reduced coloration and pale, but none showed tissue sloughing. The ability of P. lutea to survive implied its tolerance of extreme low temperatures. Here we suggest a model on the tolerance of high-latitude Porites under low-temperature stresses, which is when SSTs drop below 18°C, Porites corals contract their tentacles (losing heterotrophic capability), then cease calcification (reducing energy consumption), and meanwhile maintain relatively high levels of zooxanthellae density (sustaining host's life via photosynthetic capacity of symbiotic zooxanthellae). This study revealed remarkable acclimatization of P. lutea corals to low temperature extremes. This acclimatization is beneficial for Porites corals in the NSCS to expand their living ranges towards the higher-latitude areas and have the potential to be the incipient reef former. [ABSTRACT FROM AUTHOR]

Copyright of Chinese Journal of Applied Ecology / Yingyong Shengtai Xuebao is the property of Chinese Journal of Applied Ecology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Chinese Journal of Applied Ecology / Yingyong Shengtai Xuebao is the property of Chinese Journal of Applied Ecology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Annual radiocarbon from a massive Porites lutea coral collected from Hon Tre Island, Vietnam, South China Sea (SCS) was analyzed over a ~100-yr-long period from AD 1900 to 1986. The pre-bomb results from 1900–1953 show a steady Δ14C value of –54.4±1.8‰ (n=60). These values are similar to coral records located in the central and southern SCS and from Indonesian waters, but are lower than those from Japan. Following the input of anthropogenic bomb 14C, our results show a sharp increase in Δ14C from 1960, reaching a peak value of 155.3‰ in 1973. The Hon Tre Island post-bomb Δ14C values are lower than those of other corals located in the SCS and Japan, but higher compared to those in the Indonesian Seas. This study infers a seasonal input of upwelled water depleted in 14C from the deeper SCS basin that originates from the tropical Pacific via the Luzon Strait. The bifurcation of the North Equatorial Current feeds the surface and intermediate currents in the SCS and Makassar Strait region. However, unlike the Makassar site, this study’s coral Δ14C does not receive lower 14C water from the South Pacific Equatorial Current. The Vietnam record therefore represents a unique oceanographic position, reflecting the seasonal influence of older, deeper SCS waters that upwell periodically in this area and have modified the surface waters locally in this region over the last 100 yr. [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]

Large-amplitude internal waves (LAIW) cause intense drops in sea water temperature (6–9 °C) and acidity (0.6 pH units) within minutes, posing a major disturbance factor for shallow water corals in the Andaman Sea. During periods of elevated temperatures, however, they may provide a vital source of relief to heat-stressed corals. To assess the effect of LAIW on the thermal tolerance of the massive coral Porites lutea , we carried out a one-month reciprocal LAIW simulation experiment with coral nubbins collected from the LAIW-exposed and LAIW-sheltered sides of the Similan Islands, an offshore archipelago near the Thai Andaman shelf break (distance of sampling locations < 3 km). Corals from either origin were subjected to (1) ambient (29 °C, pH 8.39) vs. elevated (31.5 °C) temperatures; and (2) ambient temperatures with simulated LAIW (30 minute drops to 23.8 °C, pH 7.9, twice per day) vs. elevated temperatures with LAIW (30 minute drops to 24.9 °C, pH 7.9, twice per day). Simulated LAIW reduced heat stress responses in all corals. However, nubbins from the LAIW-exposed site showed a higher tolerance to the heat stress than sheltered corals, i.e. lower bleaching- and mortality rates, higher photosynthetic performances and higher protein contents at the end of the experiment, despite identical algal symbiont genotypes (ITS-2, C15). Our results suggest that LAIW-induced nutrient availability, enhanced heterotrophic feeding and thermal variability increased the upper thermal resistance of P. lutea , supporting the notion that LAIW-exposed reefs might be important refugia for coral survival in a warming ocean. [ABSTRACT FROM AUTHOR]

Porites white patch syndrome ( PWPS) is a coral disease recently described in the Western Indian Ocean. This study aimed to isolate and identify potential pathogens associated with PWPS utilizing both culture and nonculture screening techniques and inoculation trials. A total of 14 bacterial strains (those dominant in disease lesions, absent or rare in healthy tissues and considered potential pathogens in a previous study) were cultured and used to experimentally inoculate otherwise healthy individuals in an attempt to fulfil Henle-Koch's postulates. However, only one (P180R), identified as closely related (99-100% sequence identity based on 1.4 kb 16S RNA sequence) to Vibrio tubiashii, elicited signs of disease in tank experiments. Following experimental infection (which resulted in a 90% infection rate), the pathogen was also successfully re-isolated from the diseased tissues and re-inoculated in healthy corals colonies, therefore fulfilling the final stages of Henle-Koch's postulates. Finally, we report that PWPS appears to be a temperature-dependent disease, with significantly higher tissue loss ( anova: d.f. = 2, F = 39.77, P < 0.01) occurring at 30 °C [1.45 ± 0.85 cm2 per day (mean ± SE)] compared to ambient temperatures of 28 and 26 °C (0.73 ± 0.80 cm2 per day (mean ± SE) and 0.51 ± 0.50 cm2 per day (mean ± SE), respectively). [ABSTRACT FROM AUTHOR]

We report on a 41-year (winter 1970 to winter 2010)Porites luteacoral core climate record from Two-Mile Reef, Sodwana Bay, in the South-Western Indian Ocean. X-ray analysis, ultraviolet fluorescent photography and stable isotope (δ18O and δ13C) analysis revealed skeletal high-density, late-winter and low-density, late-summer bands with very little terrestrial humic input. An overall decrease in coral growth rate was seen over this period, possibly linked to global temperature and acidification trends. The stable isotopes δ18O and δ13C were predominantly out of phase, with calculated temperatures showing a slight increase over the 41-year period but with an overall decrease from 1994 to 2010. The insignificant ocean warming recorded in the coral supports the existence of a local, self-regulating, cold-water upwelling system from the adjacent shelf break and canyons that is potentially moderating coastal water temperature rise in Sodwana Bay. [ABSTRACT FROM AUTHOR]

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

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 reef coral Goniastrea aspera is regarded as one of the most environmentally tolerant species on Indo-Pacific reefs. Its demise, following a severe bleaching event in the Andaman Sea in the north-eastern Indian Ocean in 2010, was surprising in view of the rapid recovery of co-existing species such as Porites lutea. Demographic studies of G. aspera at this site showed the population was mainly composed of large individuals, which recruited in the early 1990s. These results, and size-specific mortality observed in G. aspera, post-bleaching, suggest that factors, related to size and age, may have contributed to the coral's marked decline. [ABSTRACT FROM AUTHOR]

Coral diseases are characterized by microbial community shifts in coral mucus and tissue, but causes and consequences of these changes are vaguely understood due to the complexity and dynamics of coral-associated bacteria. We used 16S rRNA gene microarrays to assay differences in bacterial assemblages of healthy and diseased colonies displaying White Plague Disease (WPD) signs from two closely related Caribbean coral species, Orbicella faveolata and Orbicella franksi. Analysis of differentially abundant operational taxonomic units (OTUs) revealed strong differences between healthy and diseased specimens, but not between coral species. A subsequent comparison to data from two Indo-Pacific coral species ( Pavona duerdeni and Porites lutea) revealed distinct microbial community patterns associated with ocean basin, coral species and health state. Coral species were clearly separated by site, but also, the relatedness of the underlying bacterial community structures resembled the phylogenetic relationship of the coral hosts. In diseased samples, bacterial richness increased and putatively opportunistic bacteria were consistently more abundant highlighting the role of opportunistic conditions in structuring microbial community patterns during disease. Our comparative analysis shows that it is possible to derive conserved bacterial footprints of diseased coral holobionts that might help in identifying key bacterial species related to the underlying etiopathology. Furthermore, our data demonstrate that similar-appearing disease phenotypes produce microbial community patterns that are consistent over coral species and oceans, irrespective of the putative underlying pathogen. Consequently, profiling coral diseases by microbial community structure over multiple coral species might allow the development of a comparative disease framework that can inform on cause and relatedness of coral diseases. [ABSTRACT FROM AUTHOR]