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THREE-DECADE changes of reef cover in Pulau Layang-Layang, Malaysia using multitemporal Landsat images

Han DHT, James D, Waheed Z, Phua MH

Mar Environ Res, 2024 May;197:106454.
PMID: 38552455 DOI: 10.1016/j.marenvres.2024.106454

Over the years, coral reefs in the South China Sea have degraded and faced severe threats from rapid development, coral bleaching, and Crown-of-Thorns Starfish (COTS) outbreak. There is limited knowledge relating to the effects of anthropogenic disturbances and natural events on the coral reefs of Pulau Layang-Layang. This study aims to assess reef cover changes by utilizing Landsat satellite images spanning from 1989 to 2022. Using the object-based image analysis method, this study classified the reef cover into three categories: coral, rock and rubble, and sand. The supervised classification had an overall accuracy of 86.41-87.38 % and Tau's coefficients of 0.80-0.81. The results showed island development and construction of artificial bird sanctuary have led to an increase in coral cover. Furthermore, it was illustrated that the impact of COTS outbreaks in 2010 and 2020 differed significantly, with the latter showing no signs of recovery. Our study underscores the importance of timely intervention to mitigate the spread of COTS. This study provides insights into the resilience and vulnerability of these ecosystems in the face of various stressors.

Matched MeSH terms: Anthozoa*
Fulltext The Coral Triangle and Strait of Malacca are two distinct hotspots of mangrove biodiversity

Goulding TC, Dayrat B

Sci Rep, 2023 Sep 22;13(1):15793.
PMID: 37737278 DOI: 10.1038/s41598-023-42057-6

Knowledge of the biogeography of marine taxa has lagged significantly behind terrestrial ecosystems. A hotspot of marine biodiversity associated with coral reefs is known in the Coral Triangle of the Indo-West Pacific, but until now there was little data with which to evaluate broad patterns of species richness in the coastal fauna of ecosystems other than coral reefs. This data is critically needed for fauna with low functional redundancy like that of mangroves, that are vulnerable to habitat loss and rising sea levels. Here we show that the diversity of mangrove fauna is characterized by two distinct hotspots in the Indo-West Pacific, associated with two habitat types: fringe mangroves in the Coral Triangle, and riverine mangroves in the Strait of Malacca, between the west coast of Peninsular Malaysia and Sumatra. This finding, based on a family of slugs of which the systematics has been completely revised, illustrates an unexpected biogeographic pattern that emerged only after this taxon was studied intensively. Most organisms that live in the mangrove forests of Southeast Asia remain poorly known both taxonomically and ecologically, and the hotspot of diversity of onchidiid slugs in the riverine mangroves of the Strait of Malacca indicates that further biodiversity studies are needed to support effective conservation of mangrove biodiversity.

Matched MeSH terms: Anthozoa*
Decadal stability in coral cover could mask hidden changes on reefs in the East Asian Seas

Chan YKS, Affendi YA, Ang PO, Baria-Rodriguez MV, Chen CA, Chui APY, et al.

Commun Biol, 2023 Jun 10;6(1):630.
PMID: 37301948 DOI: 10.1038/s42003-023-05000-z

Coral reefs in the Central Indo-Pacific region comprise some of the most diverse and yet threatened marine habitats. While reef monitoring has grown throughout the region in recent years, studies of coral reef benthic cover remain limited in spatial and temporal scales. Here, we analysed 24,365 reef surveys performed over 37 years at 1972 sites throughout East Asia by the Global Coral Reef Monitoring Network using Bayesian approaches. Our results show that overall coral cover at surveyed reefs has not declined as suggested in previous studies and compared to reef regions like the Caribbean. Concurrently, macroalgal cover has not increased, with no indications of phase shifts from coral to macroalgal dominance on reefs. Yet, models incorporating socio-economic and environmental variables reveal negative associations of coral cover with coastal urbanisation and sea surface temperature. The diversity of reef assemblages may have mitigated cover declines thus far, but climate change could threaten reef resilience. We recommend prioritisation of regionally coordinated, locally collaborative long-term studies for better contextualisation of monitoring data and analyses, which are essential for achieving reef conservation goals.

Matched MeSH terms: Anthozoa*
Fulltext Downslope migration of free-living corals (Scleractinia: Fungiidae) in typhoon-exposed reef habitats at Okinawa, Japan

Ohara T, Hoeksema BW, Wee HB, Reimer JD

Mar Environ Res, 2021 Aug;170:105445.
PMID: 34392055 DOI: 10.1016/j.marenvres.2021.105445

Offshore Onna Village, Okinawa Island, Japan, there is a large and densely covered coral assemblage of free-living mushroom corals (Scleractinia: Fungiidae) on a reef slope at depths from 20 m to 32 m, covering an area of approximately 350 × 40 m2. From previous research, it is known that migration distances of mushroom corals may depend on coral shapes, coral sizes, substrate, and bottom inclination. However, until now there have been no published examples of regular Fungiidae movement and behavior from typhoon-exposed coastlines, such as those in the western Pacific Ocean. Our surveys across three years offshore Onna Village show that mushroom corals always move in down-slope direction from shallow to deeper reef zones. The results indicated that mushroom corals migrated faster in autumn than in other seasons, and that oval-elongate fungiids, and particularly those with a smooth underside, migrated more quickly than species with other shapes. Surprisingly, we observed a negative relationship between the presence of typhoons and migration rates. We also observed active migration by fungiid individuals to escape situations in which they were threatened to become overgrown by Acropora corals, or when they needed to escape from burial underneath coral debris.

Matched MeSH terms: Anthozoa*
Chemotactic response of Vibrio coralliilyticus to mucus from various coral species

Rahman I, Al-Bar AA, Richard FS, Müller M, Mujahid A

Can J Microbiol, 2021 Jul;67(7):548-552.
PMID: 33417515 DOI: 10.1139/cjm-2020-0287

Vibrio coralliilyticus, a prominent pathogenic bacteria, is known to cause tissue damage in the coral Pocillopora damicornis and is attracted towards the coral via chemotaxis. However, the potential of V. coralliilyticus to infect most of the other coral hosts via chemotaxis is unknown. In this study, we used capillary assays to quantify the chemotactic response of V. coralliilyticus to the mucus of four tank-cultivated coral species (Cataphyllia jardine, Mussidae sp., Nemenzophyllia turbida, and Euphyllia ancora), and mucus from three wild coral species (Acropora sp., Porites sp., and Montipora sp.). The bacteria showed a positive chemotactic response to each coral mucus tested, with the highest response recorded to the mucus of Acropora sp. and the lowest response to the mucus of Montipora sp. A microfluidic chip was then used to assess the chemotactic preference of V. coralliilyticus to the mucus of the tank cultivated corals. Here too, the bacterium showed positive response, but with a slightly different ranking order. The strong chemotactic response of V. coralliilyticus towards the mucus tested could indicate a broader host range of V. coralliilyticus, and by extension, indicate a threat to weakened coral reefs worldwide.

Matched MeSH terms: Anthozoa/classification; Anthozoa/metabolism; Anthozoa/microbiology*
Fulltext Reef foraminifera as bioindicators of coral reef health in southern South China Sea

A'ziz ANA, Minhat FI, Pan HJ, Shaari H, Saelan WNW, Azmi N, et al.

Sci Rep, 2021 Apr 26;11(1):8890.
PMID: 33903697 DOI: 10.1038/s41598-021-88404-3

Pulau Tioman is a famous tourist island off Peninsular Malaysia with beautiful coral reefs. This study aims to assess the health of the coral reefs surrounding Pulau Tioman based on the application of the Foraminifera in Reef Assessment and Monitoring Index (FI). Ten sampling sites around Pulau Tioman were studied with a total of 30 samples. Eight orders, 41 families, 80 genera, and 161 species of benthic foraminifera were identified. The agglutinated type of foraminifera constituted 2-8% of the total assemblages. Calcareous hyaline and porcelaneous groups represented 79% and 19% of the total assemblages, respectively. Symbiont-bearing taxa were the most common foraminifera. The results indicate that most of the sampling sites are conducive for coral reef growth with good recoverability from future stress to the ecosystem. However, several areas with higher coastal development and tourism have reduced water and sediment quality. Therefore, the limit on the number of visitors and tourists should be revised to enable coral growth and health. The FI values in this study showed a positive correlation with good water qualities and a negative correlation with organic matter enrichment. The FI is a good measure to assess the health of a coral reef and can be applied to other reef ecosystems around Malaysia.

Matched MeSH terms: Anthozoa
Fulltext First record and molecular characterisation of two Gnathia species (Crustacea, Isopoda, Gnathiidae) from Philippine coral reefs, including a summary of all Central-Indo Pacific Gnathia species

Shodipo MO, Sikkel PC, Smit NJ, Hadfield KA

Int J Parasitol Parasites Wildl, 2021 Apr;14:355-367.
PMID: 33898237 DOI: 10.1016/j.ijppaw.2021.03.004

Due to their unusual life cycle that includes parasitic larval and free living adult stages, gnathiid isopods are typically overlooked in biodiversity surveys, even those that focus on parasites. While the Philippines sits within the region of highest marine biodiversity in the world, the coral triangle, no gnathiid species have been identified or described from that region. Here we present the first records of two gnathiid species collected from the Visayas, central Philippines: Gnathia malaysiensis Müller, 1993, previously described from Malaysia, and G. camuripenis Tanaka, 2004, previously described from southern Japan. This paper provides detailed morphological redescriptions, drawings and scanning electron microscope images as well as the first molecular characterisation of both species, Furthermore, a summary of the Central-Indo Pacific Gnathia species is provided.

Matched MeSH terms: Anthozoa
Fulltext An Indo-Pacific coral spawning database

Baird AH, Guest JR, Edwards AJ, Bauman AG, Bouwmeester J, Mera H, et al.

Sci Data, 2021 01 29;8(1):35.
PMID: 33514754 DOI: 10.1038/s41597-020-00793-8

The discovery of multi-species synchronous spawning of scleractinian corals on the Great Barrier Reef in the 1980s stimulated an extraordinary effort to document spawning times in other parts of the globe. Unfortunately, most of these data remain unpublished which limits our understanding of regional and global reproductive patterns. The Coral Spawning Database (CSD) collates much of these disparate data into a single place. The CSD includes 6178 observations (3085 of which were unpublished) of the time or day of spawning for over 300 scleractinian species in 61 genera from 101 sites in the Indo-Pacific. The goal of the CSD is to provide open access to coral spawning data to accelerate our understanding of coral reproductive biology and to provide a baseline against which to evaluate any future changes in reproductive phenology.

Matched MeSH terms: Anthozoa/physiology*
Fulltext Checklist of the coral fish fauna of Xisha Islands, China

Qiu S, Chen B, Du J, Loh KH, Liao J, Liu X, et al.

Biodivers Data J, 2021;9:e63945.
PMID: 33732033 DOI: 10.3897/BDJ.9.e63945

Background: The Xisha Islands are composed of the Yongle Islands and the Xuande Islands in Hainan Province, China. It has one of the highest species diversity in the world and is also a typical oceanic distribution area of coral reefs globally. The ichthyofauna of the Xisha Islands were recorded by underwater visual census in May 2019 and July 2020. The survey data were combined with previous records of species into the checklist of the Xisha Islands presented herein. A total of 691 species, belonging to 24 orders and 97 families, was recorded. The major families were Labridae, Pomacentridae, Serranidae, Chaetodontidae, Hexanchidae, Lutjanidae, Scaridae, Gobiidae, Scorpaenidae and Carangidae. In this study, the Coral Fish iversity Index (CFDI) of six families (Chaetodontidae, Pomacanthidae, Pomacentridae, Labridae, Scaridae and Acanthuridae) was 229, indicating 756 coral fishes. In terms of the IUCN Red List, one species is Critically Endangered (Glyphis gangeticus), six species are Endangered (Stegostoma fasciatum, Aetomylaeus maculatus, Aetomylaeus vespertilio, Epinephelus akaara, Cheilinusundulatus sp. and Xiphias gladius), 16 species are Vulnerable, and 13 species are Near Threatened in the Xisha Archipelago, so conservation should be strengthened in this area in the future.
New information: One species is a new record for China (Dischistodus pseudochrysopoecilus) and 23 species are newly found in the Xisha Islands.

Matched MeSH terms: Anthozoa
Fulltext COPEPOD AND NEMATODE PARASITES OF THE THREE-SPOTTED DAMSELFISH Dascyllus trimaculatus FROM BIDONGISLAND, TERENGGANU

PEI YING LEE, YUSRI YUSOF, MELISSA BEATA MARTIN

UMT Journal of Undergraduate Research, 2021;3(1):7-16.
MyJurnal

This study focuses on the parasites in Dascyllus trimaculatus fish in Bidong Island. Though D. trimaculatus is a common reef fish, there is lack on parasites studies of this fish in Malaysia. The objectives of this study are to identify metazoan parasites and analyse the prevalence and mean intensity the parasites in D. trimaculatus. Sampling was randomly conducted on a coral colony of 100 meters within a 15m depth at Pantai Pasir Cina,BidongIsland.ThisresearchresultedintheidentificationofacopepodLernaeocera branchialis and a nematode from the family Camallanidae. The copepods collected in this study infected 20 out of 42 D. trimaculatus specimens, whereas the nematode-like parasites collected infected 18 of out of 42 D. trimaculatus. All copepods found in the gills of D. trimaculatus had a prevalence of 4.95 and mean intensity of 47.62%, while the nematode-like parasite, which were found in the brain, had 2.72 prevalence and 42.86% mean intensity. This elucidates that both parasites are categorised as having light levelbut common frequency of infection, and the current IUCN status of D. trimaculatus has not been reported to be harmedby parasites. Though the mean intensity of both parasites isnot harmful, the prevalence are concerning and might increase in the future, with further incorporation and monitoring of climate change factors that may affect the damselfish.

Matched MeSH terms: Anthozoa
Fulltext Terpenoids from Marine Soft Coral of the Genus Xenia in 1977 to 2019

Ng SY, Phan CS, Ishii T, Kamada T, Hamada T, Vairappan CS

Molecules, 2020 Nov 18;25(22).
PMID: 33217924 DOI: 10.3390/molecules25225386

Members of the marine soft coral genus Xenia are rich in a diversity of diterpenes. A total of 199 terpenes consisting of 14 sesquiterpenes, 180 diterpenes, and 5 steroids have been reported to date. Xenicane diterpenes were reported to be the most common chemical skeleton biosynthesized by members of this genus. Most of the literature reported the chemical diversity of Xenia collected from the coral reefs in the South China Sea and the coastal waters of Taiwan. Although there was a brief review on the terpenoids of Xenia in 2015, the present review is a comprehensive overview of the structural diversity of secondary metabolites isolated from soft coral genus Xenia and their potent biological activity as reported between 1977 to 2019.

Matched MeSH terms: Anthozoa
Fulltext Quantitative dataset of shallow water reef in Pulau Bidong, Southern of South China sea during pre and post of tropical storm (Pabuk - January 2019)

Bachok Z, Safuan CDM, Roseli NH, Akhir MF

Data Brief, 2020 Oct;32:106182.
PMID: 32923531 DOI: 10.1016/j.dib.2020.106182

This article provides raw datasets of the coral reefs status in Pulau Bidong, southern of South China Sea before and after being strike by the tropical storm Pabuk on January 2019. Data were collected using a rapid coral survey method called Coral Video Transect (CVT) technique. The data were collected along a 100 m transect line set up parallel to the shoreline and at a constant depth. In total, eight transects were surveyed during both periods (pre - August 2016, post - March 2019). Back in laboratory, the footage was then extracted into non-overlapping frames or still images prior to image analysis using Coral Point Count with Excel Extension (CPCe) software. The benthic coral reefs relative percentage cover was automatically generated after the image analysis and represented by five major categories; live coral (C), algae (ALG), other invertebrates (OT), dead coral (DC), and sand silt and rock (SR). Live coral cover was identified up to the genus level. This raw dataset was used in this article. The data provided in this article could be of significant use for future studies especially on coral recovery after the natural disturbances. It can provide a baseline assessment especially for coral reefs management as well as to comprehend changes in coral health status in the face of natural and anthropogenic disturbances. The data presented here support the information in the article Safuan et al. (2020).

Matched MeSH terms: Anthozoa
Fulltext Electrical resistivity survey data for potential aquifer in Banggi Island, Sabah, Malaysia

Rahman MNIA, Jeofry H, Basarian MS

Data Brief, 2020 Oct;32:106194.
PMID: 32904202 DOI: 10.1016/j.dib.2020.106194

The survey data on potential aquifer was collected at two sites located in Banggi Island (i.e. Laksian Primary School [LPS] and Padang Primary School [PPS]), Malaysia on 25 and 26 April 2013. Both locations are geologically surrounded by various types of lithologies, namely, sandstone, mudstone, siltstone, shale, chert, conglomerate, lignite, tuff, limestone, terrace sand, gravel and coral. The resistivity data consisted of six-line pole-dipole short arrays and were recorded in-situ using SAS 4000 ABEM Lund Imaging System, together with a relay switching unit (Electrode Selector ES 464), six multiconductor cables, steel rod electrodes and jumpers. The data, namely electrode spacing, depth of investigation, subsurface resistivity, type of material and horizontal data coverage were used to assess the characteristics of the potential aquifer. The recorded data were then processed using RES2DINV software to obtain 2-D inversion model of the subsurface. The data were also equipped with six models of inverse resistivity section for both areas. The data obtained can be used by the government and stakeholders for groundwater exploration and extraction in order to provide water supplies for local communities, especially since access to these resources from the surrounding water treatment plants on the island is limited.

Matched MeSH terms: Anthozoa
Microbiota composition data for wild and captive bluestreak cleaner wrasse Labroides dimidiatus (Valenciennes, 1839)

Okomoda VT, Nurul ANA, Danish-Daniel AM, Oladimeji AS, Abol-Munafi AB, Alabi KI, et al.

Data Brief, 2020 Oct;32:106120.
PMID: 32817873 DOI: 10.1016/j.dib.2020.106120

The Labroides dimidiatus is known as the "doctor fish" because of its role in removing parasites and infectious pathogens from the body of other fishes. This important role played both in wild and captive conditions could represent a novel form of parasitic transmission process mediated by the cleaning activity of the fish. Yet, there is a paucity of data on the microflora associated with this fish which is important for tracking disease infection and generally monitoring the health status of the fish. This article, therefore, represents the first dataset for the microbiota composition of wild and captive L. dimidiatus. Wild fish samples and carriage water were gotten in Terengganu Malaysia around the corals of the Karah Island. The captive sample, however, was obtained from well-known ornamental fish suppliers in Terengganu Malaysia. Thereafter, bacteria present on the skin, in the stomach and the aquarium water were enumerated using culture-independent approaches and Next Generation Sequencing (NGS) technology. Data obtained from the three metagenomic libraries using NGS analysis gave 1,426,740 amplicon sequence reads which are composed of 508 operational taxonomic units (OTUs) for wild samples and 3,238,564 valid reads and 828 OTUs for captive samples. All sequence reads were deposited in the GeneBank (Accession numbers SAMN14260247, SAMN14260248, SAMN14260249, SAMN14260250, SAMN14260251, and SAMN14260252). The dataset presented is associated with the research article "16S rDNA-Based Metagenomic Analysis of Microbial Communities Associated with Wild Labroides dimidiatus From Karah Island, Terengganu, Malaysia" [1]. The microbiota data presented in this article can be used to monitor the health and wellbeing of the ornamental fish, especially under captivity, hence preventing possible cross-infection.

Matched MeSH terms: Anthozoa
Fulltext Effects of substratum and depth on benthic harmful dinoflagellate assemblages

Lee LK, Lim ZF, Gu H, Chan LL, Litaker RW, Tester PA, et al.

Sci Rep, 2020 07 09;10(1):11251.
PMID: 32647125 DOI: 10.1038/s41598-020-68136-6

Microhabitats influence the distribution and abundance of benthic harmful dinoflagellate (BHAB) species. Currently, much of the information on the relationships between BHABs and microhabitat preferences is based on non-quantitative anecdotal observations, many of which are contradictory. The goal of this study was to better quantify BHAB and microhabitat relationships using a statistically rigorous approach. Between April 2016 to May 2017, a total of 243 artificial substrate samplers were deployed at five locations in the Perhentian Islands, Malaysia while simultaneous photo-quadrat surveys were performed to characterize the benthic substrates present at each sampling site. The screen samplers were retrieved 24 h later and the abundances of five BHAB genera, Gambierdiscus, Ostreopsis, Coolia, Amphidinium, and Prorocentrum were determined. Substrate data were then analyzed using a Bray-Curtis dissimilarity matrix to statistically identify distinct microhabitat types. Although BHABs were associated with a variety of biotic and abiotic substrates, the results of this study demonstrated differing degrees of microhabitat preference. Analysis of the survey results using canonical correspondence analysis explained 70.5% (horizontal first axis) and 21.6% (vertical second axis) of the constrained variation in the distribution of various genera among microhabitat types. Prorocentrum and Coolia appear to have the greatest range being broadly distributed among a wide variety of microhabitats. Amphidinium was always found in low abundances and was widely distributed among microhabitats dominated by hard coral, turf algae, sand and silt, and fleshy algae and reached the highest abundances there. Gambierdiscus and Ostreopsis had more restricted distributions. Gambierdiscus were found preferentially associated with turf algae, hard coral and, to a lesser extent, fleshy macroalgae microhabitats. Ostreopsis, almost always more abundant than Gambierdiscus, preferred the same microhabitats as Gambierdiscus and were found in microbial mats as well. With similar habitat preferences Ostreopsis may serve as an indicator organism for the presence of Gambierdiscus. This study provides insight into how BHAB-specific microhabitat preferences can affect toxicity risks.

Matched MeSH terms: Anthozoa
Unfamiliar partnerships limit cnidarian holobiont acclimation to warming

Herrera M, Klein SG, Schmidt-Roach S, Campana S, Cziesielski MJ, Chen JE, et al.

Glob Chang Biol, 2020 Jul 06.
PMID: 32627905 DOI: 10.1111/gcb.15263

Enhancing the resilience of corals to rising temperatures is now a matter of urgency, leading to growing efforts to explore the use of heat tolerant symbiont species to improve their thermal resilience. The notion that adaptive traits can be retained by transferring the symbionts alone, however, challenges the holobiont concept, a fundamental paradigm in coral research. Holobiont traits are products of a specific community (holobiont) and all its co-evolutionary and local adaptations, which might limit the retention or transference of holobiont traits by exchanging only one partner. Here, we evaluate how interchanging partners affect the short- and long-term performance of holobionts under heat stress using clonal lineages of the cnidarian model system Aiptasia (host and Symbiodiniaceae strains) originating from distinct thermal environments. Our results show that holobionts from more thermally variable environments have higher plasticity to heat stress, but this resilience could not be transferred to other host genotypes through the exchange of symbionts. Importantly, our findings highlight the role of the host in determining holobiont productivity in response to thermal stress and indicate that local adaptations of holobionts will likely limit the efficacy of interchanging unfamiliar compartments to enhance thermal tolerance.

Matched MeSH terms: Anthozoa
MS-based metabolomics revealing Bornean Sinularia sp. extract dysregulated lipids triggering programmed cell death in Hepatocellular carcinoma

Ling YS, Lim LR, Yong YS, Tamin O, Puah PY

Nat Prod Res, 2020 Jun;34(12):1796-1803.
PMID: 30587039 DOI: 10.1080/14786419.2018.1531288

Soft coral, Sinularia sp. had been proven to inherit promising anti-cancer properties against variety of cancer. Current study, Sinularia sp. extract was introduced to Hepatocellular carcinoma (Hep 3B). Cell viability assay indicated the extract exhibit a dose and time dependent cytotoxicity. LC50 exhibited the lowest at 72 h post treatment estimated as 45.3 µg/mL. Morphological alterations including nuclear condensation, cytoplasm shrinkage and deformed cellular shape in treated Hep 3B were observable. Chemometric analysis revealed hydrophobic metabolites were significantly altered. Elevated vitamin D and derivatives tend to up-regulation Ca2+ and ROS subsequently triggering apoptosis. Dysregulated glycerolipids may suggest that they were biotransformed to compensate the needs of phospholipids during cell damage. Perturbation of sphingolipids, ceramide and carbohydrate-conjugated ceramides species increased the release of pro-apoptotic components reside within mitochondria and promote programmed cell death in treated Hep 3B. To conclude, MS-based metabolomics enabled the characterization of Sinularia sp. extract-induced cell death.

Matched MeSH terms: Anthozoa/chemistry*
Fulltext Corals reveal ENSO-driven synchrony of climate impacts on both terrestrial and marine ecosystems in northern Borneo

Krawczyk H, Zinke J, Browne N, Struck U, McIlwain J, O'Leary M, et al.

Sci Rep, 2020 02 28;10(1):3678.
PMID: 32111903 DOI: 10.1038/s41598-020-60525-1

Extreme climate events, such as the El Niños in 1997/1998 and 2015/16, have led to considerable forest loss in the Southeast Asian region following unprecedented drought and wildfires. In Borneo, the effects of extreme climate events have been exacerbated by rapid urbanization, accelerated deforestation and soil erosion since the 1980s. However, studies quantifying the impact of interannual and long-term (>3 decades) climatic and anthropogenic change affecting Borneo's coastal and coral reef environments are lacking. Here, we used coral cores collected in Miri-Sibuti Coral Reefs National Park, Sarawak (Malaysia) to reconstruct the spatio-temporal dynamics of sea surface temperature and oxygen isotopic composition of seawater from 1982 to 2016, based on paired oxygen isotope and Sr/Ca measurements. The results revealed rising sea surface temperatures of 0.26 ± 0.04 °C per decade since 1982. Reconstructed δ18Osw displayed positive excursion during major El Niño events of 1983, 1997/98 and 2015/16, indicating drought conditions with less river runoff, rainfall and higher ocean salinities. La Niñas were generally associated with lower δ18Osw. We observed a long-term shift from more saline conditions between 1982 and 1995 towards less saline conditions after 1995, which are in agreement with the regional freshening trend, punctuated by saline excursion during El Niños. The decadal shifts were found to be driven by the Pacific Decadal Oscillation (PDO). This study provides the first long-term data on El Niño Southern Oscillation (ENSO)-driven synchrony of climate impacts on both terrestrial and marine ecosystems in northern Borneo. Our results suggest that coral records from northern Borneo are invaluable archives to detect regional ENSO and PDO impacts, and their interaction with the Asian-Australian monsoon, on the hydrological balance in the southern South China Sea beyond the past three decades.

Matched MeSH terms: Anthozoa*
Fulltext Biophysical and anthropogenic influences on the status of Tonga's coral reefs and reef fish fishery

Smallhorn-West P, Gordon S, Stone K, Ceccarelli D, Malimali S, Halafihi T, et al.

PLoS One, 2020;15(11):e0241146.
PMID: 33201891 DOI: 10.1371/journal.pone.0241146

Despite increasing threats to Tonga's coral reefs from stressors that are both local (e.g. overfishing and pollution) and global (e.g. climate change), there is yet to be a systematic assessment of the status of the country's coral reef ecosystem and reef fish fishery stocks. Here, we provide a national ecological assessment of Tonga's coral reefs and reef fish fishery using ecological survey data from 375 sites throughout Tonga's three main island groups (Ha'apai, Tongatapu and Vava'u), represented by seven key metrics of reef health and fish resource status. Boosted regression tree analysis was used to assess and describe the relative importance of 11 socio-environmental variables associated with these key metrics of reef condition. Mean live coral cover across Tonga was 18%, and showed a strong increase from north to south correlated with declining sea surface temperature, as well as with increasing distance from each provincial capital. Tongatapu, the southernmost island group, had 2.5 times greater coral cover than the northernmost group, Vava'u (24.9% and 10.4% respectively). Reef fish species richness and density were comparable throughout Tongatapu and the middle island group, Ha'apai (~35 species/transect and ~2500 fish/km2), but were significantly lower in Vava'u (~24 species/transect and ~1700 fish/km2). Spatial patterns in the reef fish assemblage were primarily influenced by habitat-associated variables (slope, structural complexity, and hard coral cover). The biomass of target reef fish was greatest in Ha'apai (~820 kg/ha) and lowest in Vava'u (~340 kg/ha), and was negatively associated with higher human influence and fishing activity. Overall mean reef fish biomass values suggest that Tonga's reef fish fishery can be classified as moderately to heavily exploited, with 64% of sites having less than 500 kg/ha. This study provides critical baseline ecological information for Tonga's coral reefs that will: (1) facilitate ongoing management and research; and (2) enable accurate reporting on conservation targets locally and internationally.

Matched MeSH terms: Anthozoa/physiology*
Prevention is better than cure: Persian Gulf biodiversity vulnerability to the impacts of desalination plants

Sharifinia M, Afshari Bahmanbeigloo Z, Smith WO, Yap CK, Keshavarzifard M

Glob Chang Biol, 2019 Dec;25(12):4022-4033.
PMID: 31436851 DOI: 10.1111/gcb.14808

Due to extremely high rates of evaporation and low precipitation in the Persian Gulf, discharges from desalination plants (DPs) can lead to ecological stresses by increasing water temperatures, salinities, and heavy metal concentrations, as well as decreasing dissolved oxygen levels. We discuss the potential ecological impacts of DPs on marine organisms and propose mitigating measures to reduce the problems induced by DPs discharges. The daily capacity of DPs in the Persian Gulf exceeds 11 million m3 per day, which is approximately half of global daily freshwater production; multistage flash distillation (MSF) is the dominant desalination process. Results from field and laboratory studies indicate that there are potentially serious and chronic threats to marine communities following exposure to DP discharges, especially within the zoobenthos, echinodermata, seagrasses, and coral reefs. DP discharges can lead to decreases in sensitive species, plankton abundance, hard substrate epifauna, and growth rates of seagrasses. However, the broad applicability of any one of these impacts is currently hard to scale because of the limited number of studies that have been conducted to assess the ecological impacts of DP discharge on Persian Gulf organisms. Even so, available data suggest that appropriately sited, designed, and operated DPs combined with current developments in impingement and entrainment reduction technology can mitigate many of the negative environmental impacts of DPs.

Matched MeSH terms: Anthozoa*

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