Antioxidant activities of methanol extract and solvent fractions of Marine macroalga, Avrainvillea erecta (Berkeley) a. Gepp and E.S. Gepp (Dichotomosiphonaceae)

Purpose: To determine the antioxidant activity of methanol extract (ME) and solvent fractions of Avrainvillea erecta as well as their total phenolic and flavonoid contents. Methods: The antioxidant activities of ME as well as its chloroform, butanol, and aqueous fractions (CF, BF and WF, respectively) of A. erecta were evaluated via 2,2-diphenyl-1-picrylhydrazyl (DPPH), nitric oxide (NO) and hydrogen peroxide (H2O2) scavenging assays as well as ferric reducing antioxidant power (FRAP) assay. Total phenolic and flavonoid contents were determined spectrophotometrically. Results: CF and BF possessed equally high DPPH scavenging activity with half-maximal effective concentration (EC50) of 535 and 532 mg/ml, respectively. CF had stronger NO scavenging activity (EC50 743 µg/mL) than ME and BF, although weaker compared with quercetin (EC50 279 µg/ml). CF also produced the highest FRAP value (451 µmol Fe2+/g) among all samples examined. Notably, H2O2 scavenging activity was only found in CF (EC50 387 µg/ml), which was as strong (p > 0.05) as that of gallic acid (EC50 456 µg/mL). BF had the highest total phenolic content while CF had the highest total flavonoid content. Conclusion: CF of A. erecta, which has the highest flavonoid content of all the extracts evaluated, is a potential source of natural antioxidants, especially hydrogen peroxide scavengers

Scleractinian coral (Cnidaria, Hexacorallia, Scleractinia) diversity of the Mersing Islands, Peninsular Malaysia

We present a comprehensive checklist of scleractinian (hard) corals for the Mersing Islands, Malaysia based on surveys conducted at 24 reefs across protected and unprotected marine areas. A total of 261 species of corals from 16 families and one incertae sedis (Pachyseris spp.) were recorded, along with ten records that are new for the east coast of Peninsular Malaysia. Compared against the IUCN Red List, 46.7% of coral species found in the Mersing Islands were of Least Concern (LC), 29.5% as Near Threatened (NT) and 16.4% Vulnerable (V). Only one recorded species, Pectinia maxima (Moll & Best, 1984), was listed as Endangered (EN). Baseline species diversity data are essential for the monitoring and management of marine biodiversity, especially within marine protected areas. With both protected and unprotected coral reef areas in the vicinity of the widely scattered Mersing Islands, the diversity and distribution of coral species can be used as the basis for area-based conservation and management strategies. The diversity and abundance of scleractinian corals of each island or area should be surveyed periodically to ensure the appropriate level of protection is afforded to retain scleractinian biodiversity in this region

Enhancing Uptake of Nature-Based Solutions for Informing Coastal Sustainable Development Policy and Planning: A Malaysia Case Study

Nature-based Solutions (NbS) have been advocated to protect, sustainably manage, and restore natural or modified ecosystems, simultaneously providing human well-being and biodiversity benefits. The uptake of NbS differs regionally with some countries exhibiting greater uptake than others. The success of NbS also differs regionally with varying environmental conditions and social-ecological processes. In many regions, the body of knowledge, particularly around the efficacy of such efforts, remains fragmented. Having an “inventory” or “tool box” of regionally-trialed methods, outcomes and lessons learnt can improve the evidence base, inform adaptive management, and ultimately support the uptake of NbS. Using Malaysia as a case study, we provide a comprehensive overview of trialed and tested NbS efforts that used nature to address societal challenges in marine and coastal environments (here referring to mangroves, seagrass, coral reefs), and detailed these efforts according to their objectives, as well as their anticipated and actual outcomes. The NbS efforts were categorized according to the IUCN NbS approach typology and mapped to provide a spatial overview of IUCN NbS effort types. A total of 229 NbS efforts were collated, representing various levels of implementation success. From the assessment of these efforts, several key actions were identified as a way forward to enhance the uptake of Nature-based Solutions for informing coastal sustainable development policy and planning. These include increasing education, training, and knowledge sharing; rationalizing cooperation across jurisdictions, laws, and regulations; enhancing environmental monitoring; leveraging on existing policies; enabling collaboration and communication; and implementing sustainable finance instruments. These findings can be used to inform the improved application and uptake of NbS, globally.</jats:p

Contrasting Patterns of Coral Bleaching Susceptibility in 2010 Suggest an Adaptive Response to Thermal Stress

Background: \ud Coral bleaching events vary in severity, however, to date, the hierarchy of susceptibility to bleaching among coral taxa has been consistent over a broad geographic range and among bleaching episodes. Here we examine the extent of spatial and temporal variation in thermal tolerance among scleractinian coral taxa and between locations during the 2010 thermally induced, large-scale bleaching event in South East Asia.\ud \ud Methodology/Principal Findings: \ud Surveys to estimate the bleaching and mortality indices of coral genera were carried out at three locations with contrasting thermal and bleaching histories. Despite the magnitude of thermal stress being similar among locations in 2010, there was a remarkable contrast in the patterns of bleaching susceptibility. Comparisons of bleaching susceptibility within coral taxa and among locations revealed no significant differences between locations with similar thermal histories, but significant differences between locations with contrasting thermal histories (Friedman = 34.97; p,0.001). Bleaching was much less severe at locations that bleached during 1998, that had greater historical temperature variability and lower rates of warming. Remarkably, Acropora and Pocillopora, taxa that are typically highly susceptible, although among the most susceptible in Pulau Weh (Sumatra, Indonesia) where respectively, 94% and 87% of colonies died, were among the least susceptible in Singapore, where only 5% and 12% of colonies died.\ud \ud Conclusions/Significance: \ud The pattern of susceptibility among coral genera documented here is unprecedented. A parsimonious explanation for these results is that coral populations that bleached during the last major warming event in 1998 have adapted and/or acclimatised to thermal stress. These data also lend support to the hypothesis that corals in regions subject to more variable temperature regimes are more resistant to thermal stress than those in less variable environments

A matrix approach to tropical marine ecosystem service assessments in South east Asia

Ecosystem service assessments are increasingly used to support natural resource management, but there is a bias in their application towards terrestrial systems and higher income countries. Tropical marine applications are particularly scarce, especially in SE Asia. Given the growing coastal population and expansion in blue economy sectors in SE Asia, evidence to support effective marine planning, such as ecosystem service assessments, is urgently needed. Data deficiencies for marine systems, especially (but not only) in lower income countries is a significant obstacle for ecosystem service assessments. To overcome this, we develop an ecosystem service potential matrix which combines evidence taken from an extensive literature review together with expert opinion. The matrix includes both natural and modified habitats as the service providing units. The ecosystem service potential for habitats are scored at the macro level (e.g. mangrove) due to insufficient evidence to score micro-habitats (e.g. fringe, basin or riverine mangroves). The majority of evidence is available for biogenic habitats (mangroves, coral reefs and seagrass meadows) with comparatively little for sedimentary habitats. While provisioning, regulating and cultural services are scored, published evidence is more readily available for provisioning and regulating services. Confidence scores, indicating the uncertainty in the ecosystem service potential scores are included in the matrix. To our knowledge this is the first attempt to systematically capture the provision of ecosystem services from tropical marine habitats. Although initially developed for four marine biosphere reserves and protected areas in SE Asia, the generic nature of the evidence included suggests that the matrix constitutes a valuable baseline for marine ecosystem service assessments within SE Asia and provides a robust foundation for development in future work

Coral ecology of a unique continental island of Pulau Perak, Kedah, Malaysia / Affendi Yang Amri

Coral reef research in Peninsular Malaysia has mainly been concentrated on the east coast with little emphasis on the Straits of Malacca (SOM) in the west coast. The coral reefs in SOM are extremely important, more so than their east coast counterparts due to the fact that they are only a few viable coral reef ecosystems in SOM. In the northern part of SOM stands Pulau Perak, an island which has underwater vertical reef walls. Pulau Perak reef walls are unique compared to other continental islands in Peninsular Malaysia which have typical fringing reefs. In addition the scientific knowledge of reef wall coral ecology is scarce. Therefore the present study had two objectives aimed to address this knowledge gap. For the first objective a belt-quadrat method on vertical transects with 5m intervals was used from 0 - 45 m depth. The results showed significant differences between East and West reef wall benthic community substrate cover and their coral growth-forms along the depth gradient. On the East Wall similar ‘Live Coral’ cover and coral growth-forms indicated that the this wall had an analogous environment from the surface of the water until to the depths of 45 m. Whereas for the West Wall, ‘Live Coral’ cover was found to be less in deeper depths of 30-45m (p<0.001) and dominance of coral growth-forms changed with depth. These differences are speculated to be due to the orientation of the wall to sunlight and its quality. For the second objective, a modified Reef Check method with horizontal transects were used to document the benthic community substrate cover at Shallow (10 m) and Deep (20 m) depths for six distinct facing reef walls. Pulau Perak is found to be pristine as 7 out of 12 reef areas surveyed (1 Shallow and 6 Deep) were above the mean coral cover value of 42.2% for islands on the east coast of Peninsular Malaysia. Nevertheless Shallow area coral cover ranged from ‘poor’(23.8%) to ‘good’ (56.9%) and for Deep areas they ranged from ‘poor’ (16.9%) to ‘good’ (64.4%). The results also show significant differences between the six walls around the island with regards to their orientation to sunlight and depths. Three reef walls (East, West and North Walls) have significantly different substrate cover between Shallow and Deep areas. The reason for this is uncertain but the orientation of the walls to available sunlight is hypothesized to be an important factor. Only the West Wall has a ‘Hard Coral’ cover difference (p<0.01) where the Shallow area having a lower percentage cover which could have been caused by physical damage from constructing a jetty. Cluster dendrograms using ‘Hard Coral’ cover shows that the Shallow reef wall areas are divided into North and South groups whereas the Deep reef wall areas were divided into three groups which are firstly East Wall and South-east Wall, secondly North Wall and thirdly North-west Wall and West Wall. The grouping shows similar results from Objective 1 where there is a difference between East and West Walls and it is hypothesised that the shadow of the island itself cuts off the high quality light of the morning sunlight which leads to the differences in their light quality. Possible reasons for the differences between reef walls which included several physical factors such as sea water temperature, hydrodynamics, upwelling and in particular light quality are discussed. The hypothesis that the orientation of the reef walls to sunlight is the main factor affecting their substrate cover is to be tested in future studies. A comprehensive sustainable development plan to conserve the island reef walls is recommended

Distributions of particulate and dissolved phosphorus in aquatic habitats of Peninsular Malaysia

Particulate phosphorus was the dominant phosphorus species and accounted for 72 ± 5% of total phosphorus in coastal habitats, 63 ± 4% in estuaries, 58 ± 6% in lakes and 80 ± 7% in aquaculture farms whereas dissolved inorganic phosphorus (DIP) and dissolved organic phosphorus (DOP) were minor components. Correlation analyses (DIP vs Chl a; R2 = 0.407, df = 31, p < 0.001) suggested phosphorus limiting conditions in lakes, which was corroborated with the highest alkaline phosphatase activity (APA) that fluctuated from 0.38 to 41.14 nmol L−1 min−1. In contrast, APA was elevated in coastal habitats and estuaries only when DIP concentration decreased below 0.9 μM. Moreover size-fractionation experiment showed that the highest APA was detected in the 0.2–2 μm pico-size fraction. Our results suggested that the main APA in coastal habitats and estuaries was from phototrophic pico-eukaryotes and heterotrophic bacteria, and regulated largely by DIP availability

Marine Autotroph-Herbivore Synergies: Unravelling the Roles of Macroalgae in Marine Ecosystem Dynamics

Species invasion is a leading threat to marine ecosystems worldwide, being deemed as one of the ultimate jeopardies for biodiversity along with climate change. Tackling the emerging biodiversity threat to maintain the ecological balance of the largest biome in the world has now become a pivotal part of the Sustainable Development Goals (SDGs). Marine herbivores are often considered as biological agents that control the spread of invasive species, and their effectiveness depends largely on factors that influence their feeding preferences, including the specific attributes of their food&ndash;the autotrophs. While the marine autotroph-herbivore interactions have been substantially discussed globally, many studies have reported contradictory findings on the effects of nutritional attributes and novelty of autotrophs on herbivore feeding behaviour. In view of the scattered literature on the mechanistic basis of autotroph-herbivore interactions, we generate a comprehensive review to furnish insights into critical knowledge gaps about the synergies based largely on the characteristics of macroalgae; an important group of photosynthetic organisms in the marine biome that interact strongly with generalist herbivores. We also discuss the key defence strategies of these macroalgae against the herbivores, highlighting their unique attributes and plausible roles in keeping the marine ecosystems intact. Overall, the feeding behaviour of herbivores can be affected by the nutritional attributes, morphology, and novelty of the autotrophs. We recommend that future research should carefully consider different factors that can potentially affect the dynamics of the marine autotroph-herbivore interactions to resolve the inconsistent results of specific attributes and novelty of the organisms involved

Identification of Novel Cytotoxic Peptide KENPVLSLVNGMF from Marine Sponge Xestospongia testudinaria, with Characterization of Stability in Human Serum

Resistance and side effects are common problems for anticancer drugs used in chemotherapy. Thus, continued research to discover novel and specific anticancer drugs is obligatory. Marine sponges hold great promise as a source of potent cytotoxic peptides with future applications in cancer treatments. This study aimed to purify and identify cytotoxic peptides from the protein hydrolysates of the giant barrel sponge Xestospongia testudinaria, guided by a cytotoxicity assay based on the human cervical cancer cell line (HeLa). Comparison among trypsin, chymotrypsin, papain and alcalase hydrolysates of X. testudinaria revealed papain hydrolysate (PH) to be the most active. PH was purified consecutively by membrane ultrafiltration, gel filtration chromatography, and reversed-phase high performance liquid chromatography (RP-HPLC). Following liquid chromatography-tandem mass spectrometric analysis, two peptides were identified from the most cytotoxic RP-HPLC fraction: KENPVLSLVNGMF and LLATIPKVGVFSILV. Between the two, only the synthetic peptide KENPVLSLVNGMF showed cytotoxicity toward HeLa cells in a dose-dependent manner. KENPVLSLVNGMF (EC50 0.67 mM) was 3.8-fold more cytotoxic compared with anticancer drug 5-fluorouracil (EC50 2.56 mM). Furthermore, KENPVLSLVNGMF show only marginal 5% cytotoxicity to Hek293, a non-cancerous, human embryonic kidney cell line, when tested at 0.67 mM. The half-life of the peptide was 3.2 ± 0.5 h in human serum in vitro, as revealed by RP-HPLC analyses. These results suggest that KENPVLSLVNGMF identified from X. testudinaria papain hydrolysate has potential applications as peptide lead in future development of potent and specific anticancer drugs

An updated checklist of the marine fish fauna of Redang Islands, Malaysia

Redang Islands Marine Park consists of nine islands in the state of Terengganu, Malaysia. Redang Island is one of the largest off the east coast of Peninsular Malaysia, which is famous for its crystal-clear waters and white sandy beaches. The ichthyofauna of the Redang archipelago was surveyed by underwater visual observations between August 2016 and May 2018. Census data were compiled with existing records into the checklist of the marine fish of the Redang archipelago presented herein. A total of 314 species belonging to 51 families were recorded. The most speciose families (Pomacentridae, Labridae, Scaridae, Serranidae, Apogonidae, Carangidae, Gobiidae, Chaetodontidae, Lutjanidae, Nemipteridae and Siganidae) were also amongst the most speciose at the neighbouring Tioman archipelago (except Chaetodontidae). The coral fish diversity index value for the six families of coral reef fishes (Chaetodontidae, Pomacanthidae, Pomacentridae, Labridae, Scaridae and Acanthuridae) of the study sites was 132. We estimated that there were 427 coral reef fish species in the Redang archipelago. According to the IUCN Red List, eight species are Near Threatened (Carcharhinus melanopterus, Chaetodon trifascialis, Choerodon schoenleinii, Epinephelus fuscoguttatus, E. polyphekadion, Plectropomus leopardus, Taeniura lymma and Triaenodon obesus), eleven are Vulnerable (Bolbometopon muricatum, Chaetodon trifasciatus, Chlorurus sordidus, Dascyllus trimaculatus, Epinephelus fuscoguttatus, E. polyphekadion, Halichoeres marginatus, Heniochus acuminatus, Nebrius ferrugineus, Neopomacentrus cyanomos and Plectropomus areolatus) and three are Endangered (Amphiprion clarkia, Cheilinus undulatus and Scarus ghobban) in the Redang archipelago. Five species are new records for Malaysia (Ctenogobiops mitodes, Epibulus brevis, Halichoeres erdmanni, H. richmondi and Scarus caudofasciatus) and 25 species are newly recorded in the Redang archipelago