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Modern Benthic Foraminifera in the Coral Reefs of Bidong Island, Terengganu
Abstract
An assessment of modern benthic foraminiferal species occurrences was carried out in the coral reefs environment of Bidong Island, Terengganu. Foraminiferal samples were collected by SCUBA divers at 12 transects around the island. Rose Bengal dye was mixed into formalin (10%) during the preservation process. It was used to distinguish living specimens from empty tests in the samples. There were 32 species of benthic foraminifera found in the study area. These species belong to two orders (Rotaliida and Miliolida), ten families and 15 genera. Amphistegina was the most dominant genus that occurred in all sampling stations. This study is the first record of benthic foraminiferal occurrence in Bidong Island, Terengganu. Fossil benthic foraminifera are used as proxies in interpreting past environments especially in the fields of paleobathymetry, paleoenvironment and paleoclimate. Modern benthic foraminiferal assemblages are useful in aiding the interpretations of past environments using these proxies. Modern benthic foraminifera can also be applied as bioindicators in environmental monitoring studies.KeywordsBidong IslandCoral reefsDistributionMalay basinModern benthic foraminifera
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Biogeography of macro- and micro-organisms in the deep sea is, in part, shaped by naturally occurring heterogeneous habitat features of geological and biological origin such as seeps, vents, seamounts, whale and wood-falls. Artificial features including shipwrecks and energy infrastructure shape the biogeographic patterns of macro-organisms; how they influence microorganisms is unclear. Shipwrecks may function as islands of biodiversity for microbiomes, creating a patchwork of habitats with influence radiating out into the seabed. Here we show microbiome richness and diversity increase as a function of proximity to the historic deep-sea shipwreck Anona in the Gulf of Mexico. Diversity and richness extinction plots provide evidence of an island effect on microbiomes. A halo of core taxa on the seabed was observed up to 200 m away from the wreck indicative of the transition zone from shipwreck habitat to the surrounding environment. Transition zones around natural habitat features are often small in area compared to what was observed at Anona indicating shipwrecks may exert a large sphere of influence on seabed microbiomes. Historic shipwrecks are abundant, isolated habitats with global distribution, providing a means to explore contemporary processes shaping biogeography on the seafloor. This work is a case study for how built environments impact microbial biodiversity and provides new information on how arrival of material to the seafloor shapes benthic microbiomes.
elements in the surficial sediments were studied in an attempt to establish their concentration in the Bengal coast. It was revealed that the majority of the trace elements have been introduced into the Bengal marine from the riverine inflows that are also affected by the impact of industrial, ship breaking yard, gas production plant, and urban wastes. The concentration of heavy metals was measured using Atomic Absorption Spectroscopy and Energy Dispersive X-ray fluorescence instruments. The highest concentrations for several trace elements were thus recorded which generally decrease with distance from the coast. It was observed that the heavy metal concentrations in the sediments generally met the criteria of international marine sediment quality. However, both the contamination factor and pollution load index values suggested the elevation of some metals' concentrations in the region. Constant monitoring of the Bengal coast water quality needs to be recorded with a view to minimizing the risk of health of the population and the detrimental impacts on the aquatic ecosystem.
The groundwater samples of Pulau Bidong, Terengganu, Malaysia were collected from five sampling stations from June to October 2016. Physical parameters such as temperature, specific conductivity, dissolved oxygen (DO), pH, salinity, and DO saturation were measured in-situ by using handheld device. Meanwhile, total suspended solid (TSS), total dissolved solid (TDS), nitrate (NO3⁻), nitrite (NO2⁻), ammonium (NH4⁺) and phosphate (PO4³⁻) were analysed and detected using UV-Vis Spectrophotometer. The inorganic nutrients (NO3⁻, NO2⁻, NH4⁺ and PO4³⁻) were ranged from 0.000 to 4.310 mg/L, 0.000 to 0.190 mg/L, 0.000 to 0.807 mg/L and 0.003 to 0.028 mg/L, respectively. The monthly trends of specific conductivity, DO, salinity, DO saturation, NO3⁻, NO2⁻ and NH4⁺ demonstrated significant variation in June (the lowest rainfall) compared to other months. Correlation matrix revealed that temperature was associated with the specific conductivity, and NH4⁺ strongly correlated with DO, NO3⁻ and NO2⁻. Nevertheless, there is a strong negative correlation between physicochemical parameters and monthly rainfall distribution. Notably, future studies are required for long-term monitoring to ensure the good quality of groundwater from Pulau Bidong. The spatial and temporal variability of the present data has been reported by Tan et al. [1].
Although methods were proposed for eliminating sun glint effects from airborne and satellite images over coral reef environments, a method was not proposed previously for unmanned aerial vehicle (UAV) image data. De-glinting in UAV image analysis may improve coral distribution mapping accuracy result compared with an uncorrected image classification technique. The objective of this research was to determine accuracy of coral reef habitat classification maps based on glint correction methods proposed by Lyzenga et al., Joyce, Hedley et al., and Goodman et al.. The UAV imagery collected from the coral-dominated Pulau Bidong (Peninsular Malaysia) on 20 April 2016 was analyzed in this study. Images were pre-processed with the following two strategies: Strategy-1 was the glint removal technique applied to the whole image, while Strategy-2 used only the regions impacted by glint instead of the whole image. Accuracy measures for the glint corrected images showed that the method proposed by Lyzenga et al. following Strategy-2 could eliminate glints over the branching coral—Acropora (BC), tabulate coral—Acropora + Montipora (TC), patch coral (PC), coral rubble (R), and sand (S) with greater accuracy than the other four methods using Strategy-1. Tested in two different coral environments (Site-1: Pantai Pasir Cina and Site-2: Pantai Vietnam), the glint-removed UAV imagery produced reliable maps of coral habitat distribution with finer details. The proposed strategies can potentially be used to remove glint from UAV imagery and may improve usability of glint-affected imagery, for analyzing spatiotemporal changes of coral habitats from multi-temporal UAV imagery.
The intertidal zone or littoral zone is the part of the ocean that is underwater during high tide and exposed during low tide. The intertidal ecosystem is continually under pressure from both humans and the natural elements of waves and tidal shifts. The organisms that reside here must be able to tolerate extreme changes to physicochemical factors such as light, temperature, water movement, salinity and oxygen. Gastropods from phylum Mollusca are highly resistant and adaptable to extreme changes in the environment. This study investigates the diversity, abundance, and distribution of tropical intertidal gastropods in different areas. Also, it examines how shell morphometrics and biomass affect these factors. Sampling was done in Pantai Pasir Cina (PPC) and Pantai Pasir Pengkalan (PPP) at Pulau Bidong, Malaysia in August 2018. Transect lines of 60 m × 10 m were laid out perpendicular to the shore. Six quadrats of 1 m 2 were placed at three tidal zonation's: high, mid, and low tide. A total of 1326 individual gastropods represented by eight families (Littorinidae, Muricidae, Planaxidae, Siphonariidae, Neritidae, Nacillidae, Patellidae and Trochidae) were recorded, along with five subclasses namely Ceanogastropoda, Heterobranchia, Neritimorpha, Patellogastropoda and Vetigastropoda. A total number of 19 species were recorded from both study sites. The Shannon diversity index, H' showed that at the intertidal zones at both locations the diversity was less than two, indicating low diversity. In contrast, Simpson's index, D at all intertidal zones at both sites had values of almost one, indicating a high level of dominance. This pattern is also seen for evenness indices such as J' and Ep' where all values are close to one, which indicates complete evenness for all tidal zones. The diversity t-test revealed significant differences between the sites of PPC and PPP, t (1192.5) =-4.9652, p < 0.05. The SHE analysis of the two sites showed a lognormal pattern. Community structures of intertidal zones at PPC and PPP are between 'more equally' and 'very equally' and fall under the 'good' or the 'very good' categories. Although it is the baseline, a future study on spatial heterogeneity and temporal variability are needed to provide more comprehensive knowledge of malacofauna communities and their ecological importance.
Climate projections suggest-with substantial certainty-that global warming >1.5 °C will occur by mid-century (2050). Population is also projected to increase, amplifying the demands for food, fuel, water and sanitation, which, in turn, escalate nutrient pollution. Global projections of nutrient pollution, however, are less certain than those of climate as there are regionally decreasing trends projected in Europe, and stabilization of nutrient use in North America and Australia. In this review of the effects of eutrophication and climate on harmful algae, some of the complex, subtle, and non-intuitive effects and interactions on the physiology of both harmful and non-harmful taxa are emphasized. In a future ocean, non-harmful diatoms may be disproportionately stressed and mixotrophs advantaged due to changing nutrient stoichiometry and forms of nutrients, temperature, stratification and oceanic pH. Modeling is advancing, but there is much yet to be understood, in terms of physiology, biogeochemistry and trophodynamics and how both harmful and nonharmful taxa may change in an uncertain future driven by anthropogenic activities.
Research on mercury (Hg) in aquatic ecosystems in China has focused mainly on fish, with little research on the base of the food chain and Hg bioaccumulation mechanisms. This paper summarizes research progress pertaining to the characteristics, current status, and trends of Hg accumulation in the aquatic food chain in China, analyzes the effects of human activities on the transmission and accumulation of Hg in aquatic food chains, and assesses their risks to human and ecosystem health. A comparison of fish samples in China between 2000 and 2018 indicates that their total Hg content remains at relatively safe levels. However, because current information is generally insufficient to confirm how anthropogenic activities affect transformation and bioaccumulation in the aqueous environment, Hg isotope studies should be a focus of research on aquatic food webs. Additionally, more attention should be paid to Hg transport and bioaccumulation in the basic food chain by focusing on multi-contaminant joint exposure studies and establishing Hg bio-transport models.
The rise in atmospheric carbon dioxide (CO2) concentration due to emissions associated with economic development is altering ocean chemistry, a process known as ocean acidification. The resultant decrease in oceanic pH will affect marine organisms, in particular those which build their skeletons through calcification such as scleractinian corals. The aim of this research was to analyse the likely impact of changing CO2 concentrations and thus seawater pH on the growth rate of two common corals, Isopora palifera and Acropora hyacinthus. This research was conducted at the Marine, Coastal and Small Island Research Centre, Universitas Hasanuddin, Indonesia. Samples of Isopora palifera and Acropora hyacinthus were collected along an inshore-offshore cross-shelf gradient from 3 sites: Pulau Karanrang (inner zone), Pulau Badi (intermediate zone), and Pulau Kapoposang (outer zone). A fully randomised research design was used with three replicates for each of three CO2 treatments: 390 ppm (control), 550 ppm (2030 prediction), 1000 ppm (2050 prediction). The samples were weighed weekly for 1 month (digital balance, accuracy 0.1 mg). ANOVA analysis with post hoc Tukey Test showed a significant (p < 0.05) between treatment difference in growth rate for both Isopora palifera and Acropora hyacinthus (P<0,05). The corals from all three zones exhibited positive growth at 390 ppm CO2, and negative growth at CO2 concentrations of 550 ppm and 1000 ppm.
Coral reefs experiencing ocean acidification (OA) are likely to recover much more slowly from damage caused by acute events such as mass bleaching because OA slows coral reef growth and reproduction. To maintain reefs in a net growth or net-neutral condition, curbing the impact of OA is therefore necessary. A variety of mitigation and adaptation strategies have been proposed to abate OA impacts on reefs. However, detailed guidance for managers on the types, effectiveness, or costs of different local interventions to address OA is scarce. To advance the discussion about available interventions, this review explores and compares mitigation and adaptation techniques that have been proposed to abate OA impacts on coral reefs. We focus primarily on four categories of interventions intended to address different ecosystem service changes: phytoremediation, chemical remediation, reef restoration, and assisted evolution. We briefly touch on traditional restoration methods like marine protected areas (MPAs) and reducing secondary sources of stress. Of the techniques reviewed, most are costly and do not scale at the same pace as global reef loss. Nor do they address the root cause of OA, global carbon emissions. That said, intervention should not be an all or nothing approach; some techniques may be worth implementing at smaller scales in a coordinated way. Working to save pieces of ecosystems and buying time may help ensure that there is more to rebuild from in the future. Despite the seemingly high price tag of many of these techniques, given the potential value of regained ecosystem services, net gains may exceed implementation costs. It is certain, however, from the limited reach of coral reef interventions, that they must be undertaken as part of a suite of global-scale interventions including atmospheric CO 2 reduction to preserve coral reef ecosystem function and benefits to humanity.
The community structure of marine nematode assemblages in the southern-west of Borneo was investigated with special focus on the horizontal distribution from high tide to subtidal area. A transect study had been conducted in Teluk Awar. Nine stations were chosen from the Mean High Water Neap to Mean Low Water Neap level. The physico-chemical characteristic of water and sediments were determined both ex situ. One-way ANOVA showed that the environmental variables among stations were significantly different (except chlorophyll a and total organic matter). Multi-dimensional scaling demonstrated three distinct patterns among the stations while dendrogram showed high dissimilarity percentage in the species distribution among stations. In conclusion, the results showed that environmental variables such as clay, total organic matter and temperature were affecting the nematode distribution pattern in Teluk Awar.
The landscape of Tasik Kenyir and Setiu are consists of lowland dipterocarp forests which bear to sustain various species of birds. A study was conducted to determine the bird assemblages in two lowland dipterocarp forests at Tasik Kenyir and Setiu from July to October 2016 by using two different methods; mist-netting and point count methods. A total of 82 species, 28 families and 343 individuals were recorded at both sites. Tasik Kenyir showed a higher number of species with 53 species compared to Setiu with account of only 48 species. However, Setiu recorded a higher number of individuals (184 individuals) compared to Tasik Kenyir (159 individuals) with the same number of families (23 families). The most commonly found species at Tasik Kenyir is Cream Vented Bulbul, Pycnonotus simplex, and Barn Swallow, Hirundo rustica at Setiu, with 15 and 28 individuals respectively. Point count method recorded a total of 57 species (51%), while mist-netting recorded 40 species (36%) and both methods shared 14 species (13%). As a conclusion, knowledge on the current population of birds and their habitat status may provide beneficial information towards effective conservation management in the studied areas.
Nursery habitats provide increased survival and growth and are a crucial early life-stage component for many fish and invertebrate populations. The biogenic structures that provide this nursery function, however, are increasingly degraded. Therefore, any effort to conserve, restore or replace habitat with artificial structure should be guided by an understanding of the value provided by that nursery habitat. Here, we experimentally manipulated structure across a number of sites by inserting pinnind bivalve mimics into the seabed and deploying video cameras to observe the response of post-settlement stage snapper, Chrysophrys auratus (Forster in Bloch and Schneider 1801). We also collected a range of environmental variables across these sites to determine the relative importance to snapper of benthic vs. pelagic productivity. While the abundance of snapper was low, our results demonstrated a strong association to structure relative to control plots. The environmental variable with the highest correlation to snapper abundance was the abundance of zooplankton eaten by snapper. This result was well supported by the dominance of zooplankton over small benthic invertebrates in snapper gut contents, and the weak influence of benthic infauna in our regression models. These regressions also demonstrated that when combined with zooplankton abundance, turbidity had a negative relationship to snapper abundance. This highlights the importance of relatively clear water in estuaries, which allows post-settlement snapper to more efficiently consume the zooplankton that are present in the water column. The third component that post-settlement snapper require is of course the presence of benthic structure. While benthic habitat structure was the strongest factor affecting juvenile snapper abundance, we did not find any correlations to suggest that this importance was related to energetic sheltering and access to locations with high food flux.
Aim: The age composition of Monogrammed monocle bream, Scolopsis monogramma and Fork-tailed threadfin bream, Nemipterus furcosus in fringing shallow water of Bidong Island, South China Sea was studied for the first time. Methodology: Fish samples were collected by baited portable traps, gill netting and hand-lining during pre-northeast monsoon season. A pair of otoliths were extracted by the open hatch method, cleaned and embedded in epoxy resin. The fish age was determined by counting the opaque zone in sectioned otoliths and was validated by marginal increment analysis. Results: This study found that both species comprised of older fish with S. monogramma in between 4 to 9 years and 4 to 8 years in N. furcosus. No smaller or younger fish was observed, probably due to selective sampling efforts. The marginal increment analysis recorded an increase of 11% from August to September for S. monogramma and by using this increase, the growth ring was expected to be completed in April. In N. furcosus, a 14% increase was observed and expected to be completed in January. Interpretation: This study concluded that the S. monogramma and N. furcosus in the fringing shallow water of Bidong Island comprised of older individuals. Further studies should be carried out by extending the duration of sampling, using a wider range of legal mesh and hook sizes to potentially obtain a more comprehensive size range to investigate the growth parameters of the fish.
Currently, heavy metal pollution becomes a serious problem all over the world. These toxic metals are released into the environment either by natural phenomena or due to extensive industrialization. The effluents containing heavy metals mixed with soil/water and change their natural composition. These heavy metals also cause damage to the vital body organs of animals as well as human. The heavy metal pollution inhibits the biodegradation of the chlorinated organic compounds (another type of environmental pollution) by interacting with metabolizing enzymes and inhibits their functioning. Earlier studies described that heavy metals cannot be fully removed or degraded from the environment, but they can be effectively neutralized or transformed into less toxic forms so that their harmful effect on the environment can be reduced. The microbial system plays a major role in the transformation of heavy metals in the environment. A considerable advancement has been made during recent years to degrade or transform the heavy metals by utilizing the genetically engineered microorganisms. These transgenic are very much efficient in heavy metal transformations and still, we have to discover, more to utilize their full biotransformation potential.
In the present review article, the detailed description of the adverse effects of four heavy metals (Arsenic, Lead, mercury, and Chromium) and their pollution on our environment and human beings is discussed. Furthermore, the use of microorganisms/GE organisms for the bioremediation of heavy metals from the environment is also discussed along with their detailed bioremediation mechanism.
This book contains research findings from three major study areas, natural sciences, social sciences, and public policy and management. The focus area extends over geographical zones ranging from mountainous area of Mount Gagau in the Taman Negara National Park, down to the coastal islands of Bidong, Redang and Perhentian on the eastern coast of Peninsular Malaysia.
Chapters on natural sciences examine the physicochemical characteristics of water, physiological and ecological constraints to geological and climatological aspects. The social science and management chapters observe the rich ethno-heritage of local communities and how they interact and develop as a culture, and public policy for sustainable management. Viewpoints from political science, history, sociology, economics, anthropology and management science are also taken into account.
This book is intended for researchers and graduate students to create an understanding of the rich heritage, while policy makers plan for future generations. Readers will benefit from this book by studying the gaps in the current knowledge and move to develop further research to understand the unexplored forest canopies and the dynamics of the changing Greater Kenyir landscapes.
https://www.springer.com/us/book/9783319922638
https://www.amazon.in/Greater-Kenyir-Landscapes-Environmental-Sustainability/dp/3319922637
Nematodes present in all substrates and sediment types with an enormous number of species. The studies on free-living marine nematodes are still limited in Malaysia. The present study provides general information on genus checklist of free-living marine nematodes in the northern part of Peninsular Malaysia in a different ecosystem which are intertidal zones of estuarine, sandy beach and mangrove ecosystems. Samples were randomly collected at three stations in each ecosystem. A total of 34 genera (22 families and ten suborders) were recorded in three ecosystems. Each ecosystem had common genera which also commonly found worldwide. Viscosia genus was observed in all three ecosystems. The nematode genera of Estuary and mangrove ecosystems had greater similarities than those in the sandy beach.
A study of the bat diversity was conducted in Hulu Terengganu dipterocarp forest and Setiu Wetland Beach Ridges Interspersed with Swales (BRIS) forest in Terengganu, to study the species diversity, composition and stratification of fruit bats from the understorey to the forest canopy. Mist nets were set up at the understorey, sub-canopy and canopy layer while harp traps were set up at the understorey layer. We recorded 170 individuals from six families’ compromised 21 species from Hulu Terengganu dipterocarp forests and four species from Setiu Wetland BRIS forests throughout the sampling period. Megaerops ecaudatus and Cynopterus brachyotis were the most dominant species in Hulu Terengganu dipterocarp forest and Setiu Wetland BRIS forests. Our study also recorded two species with new distributional records for the east coast of Peninsular Malaysia, namely, Rhinolophus chiewkweeae and Chaerephon johorensis in Hulu Terengganu dipterocarp forests. Potential factors that might influence the results were in terms of the canopy covers, the structural complexity of canopy, food availability and spatial characteristics. This study was able to increase the knowledge on the species diversity and composition of bats in Hulu Terengganu dipterocarp forest and Setiu Wetland BRIS forest, thus, further aid in the effort of bat conservation in both areas.
Most marine ecologists have in the past 25 years changed from supporting a passive-dispersal paradigm for larval marine fishes to supporting a biophysical-dispersal paradigm wherein the behaviour of larvae plays a central role. Research shows larvae of demersal perciform fishes have considerable swimming and orientation abilities over a major portion of their pelagic larval duration. These abilities depend on sensory function, and some recent research has indicated anthropogenic acidification of the oceans will by the end of the century result in sensory dysfunction. This could strongly alter the ability of fish larvae to orientate in the pelagic environment, to locate suitable settlement habitat, to bet-hedge, and to colonize new locations. This paper evaluates the available publications on the effects of acidification on senses and behaviours relevant to dispersal of fish early life-history stages. A large majority of studies tested CO2 values predicted for the middle to end of the century. Larvae of fourteen families—all but two perciform—were studied. However, half of studies used Damselfishes (Pomacentridae), and except for swimming, most studies used settlement-stage larvae or later stages. In spite of these taxonomic and ontogenetic restrictions, all but two studies on sensory function (chemosensation, hearing, vision, detection of estuarine cues) found deleterious effects from acidification. The four studies on lateralization and settlement timing all found deleterious effects from acidification. No clear effect of acidification on swimming ability was found. If fish larvae cannot orientate due to sensory dysfunction, their dispersal will, in effect, conform to the passive dispersal paradigm. Modelling incorporating larval behaviour derived from empirical studies indicates that relative to active larvae, passive larvae will have less self-recruitment, higher median and mean dispersal distances, and lower settlement rates: further, bet hedging and colonization of new locations will decrease. The biophysical dispersal paradigm will be lost in theory and in fact, which is predicted to result in lower recruitment and less bet hedging for demersal, perciform fishes. More research is required to determine if the larvae of other Orders will be effected in the same way, or if warm- and cold-water fish faunas will be similarly effected.
The aim of the present study was to determine the level of selected toxicants in water, their bioaccumulation and effects on antioxidant enzymes i.e. superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) in vital organs (gills, liver and kidney) of fish, Cirrhina mrigala. The 3 different representative water samples and 60 fish samples (20 fish from each site) were collected from three sites i.e. fishfarm, hatchery and Indus River of Punjab, Pakistan. The results showed differences in physico-chemical parameters of water samples collected from all the sites. The concentrations of Zinc (Zn), copper (Cu) and nickel (Ni) were higher in river water as compared to farm and hatchery. Different organs of fish collected from different sites showed variations in their metal concentration. In Indus River fish, the concentrations of metals were highest in liver followed by kidney and gills. The Indus River fish also exhibited highest SOD activity in all the organs as compared to farm and hatchery fish. The activity of CAT enzyme was higher in kidneys and gills of farm fish compared to the liver of hatchery fish. The maximum POD activity was recorded in liver, kidney and gills of hatchery fish. This study reveals that fish could acquire higher uptake of metals due to excessive pollution of heavy metals and other toxic elements in river water. In response to metals toxicity, the antioxidant system can be useful as an early warning tool in natural monitoring studies.
The appropriate behavioural response to predation risk is critical to survival; however, behavioural responses can be subjected to trade-offs. For example, individuals may engage in riskier foraging behaviour to secure sufficient energy if resources are limited. Additionally, elevated CO2 can influence foraging and antipredator behaviour of marine organisms. Yet, how the availability of energetic resources may influence antipredator behaviour in an elevated CO2 environment is unknown. We tested the effects of food ration (low and high: 4 and 8% of body weight per day, respectively) on antipredator behaviour at ambient (489 µatm) and elevated (1022 µatm) CO2 in juvenile Amphiprion percula at 50 d post-hatching. Juveniles were from parents held at either ambient or elevated CO2, as parental exposure can influence phenotypic response in offspring. Antipredator behaviour was severely impaired by elevated CO2, with juveniles reared at elevated CO2 exhibiting no change in feeding rate in the presence of the predator cue compared with a >67% reduction in feeding rate in ambient CO2 fish. By contrast, food ration had a minor effect on the change in feeding rate in response to the predator cue, with only a 2.3% difference between high and low food ration fish. The effect of elevated CO2 on antipredator behaviour of juveniles was not influenced by food ration. Parental exposure to elevated CO2 influenced the baseline feeding rate and exhibited a small carry-over effect in elevated CO2 juveniles. These results suggest that reef fish could exhibit riskier behaviour at elevated CO2 levels, regardless of the energetic resources available.
In order to assess the bioaccumulation of metals associated with gender, tissues, and their potential ecological risk, four species of fish were collected from the Yongshu Island in the Southern South China Sea. Metals and stable Pb isotopes in their tissues (muscle, gill, liver, intestine, and ovary) were determined. The concentrations of metals (mg/kg, dry weight) in these species were ND–21.60 (Cd), 1.21–4.87 (Cr), 0.42–22.4 (Cu), 1.01–51.8 (Mn), 0.30–3.28 (Ni), 6.04–1.29 × 10 ³ (Zn), 14.89–1.40 × 10 ³ (Fe), and 0.22–3.36 (Pb). In general, the liver and intestine absorbed more metals than the other tissues. Metals accumulation can be influenced by gender and feeding behavior and in fact, female fish and dietary exposure are more prone to accumulate metals. In addition, Pb isotopic ratios indicated that all species had significant biological fractionation, which may not make them good tracers for source identification. The metal concentrations of most samples were lower than the national standard values of the FAO (USA), which suggested that human consumption of these species may not cause health risks. However, since the surrounding areas are developing rapidly, the potential environmental risk of metals will intensify and should receive more attention.
[The article is available to download free with Open Access here http://www.tandfonline.com/doi/abs/10.1080/01436597.2017.136801]
Treating the threat of climate change in the Caribbean as a case study instructive for responses globally, this article examines the social and political relations of climate change. It argues for an analysis taking into account the ways in which the histories of imperialism and colonialism have shaped contemporary global ‘development’ pathways. The article charts how Caribbean vulnerability to temperature rises of more than 1.5°C of warming comprise an existential threat structured by contemporary social relations that are imperialist in character. Hope can be taken from a politics of climate justice which acknowledges the climate debts owed to the region.
[The article is available to download free with Open Access here http://www.tandfonline.com/doi/abs/10.1080/01436597.2017.136801]
Removal of registered nematicides from the marketplace has increased interest in using biological agents for nematode control. Numerous invertebrates have been observed as predators of free-living and phytoparasitic nematodes. A copepod, Phyllognathopus viguieri (Maupas) (order Harpacticoida) was collected from a Florida nursery and cultured in the laboratory. Phyllognathopus viguieri is widely distributed in moist soils. It preys on at least seven species of phytoparasitic nematodes, two species of free-living nematodes, and one entomopathogenic species. After one hour, 130 copepods had consumed 90% of 1000 2nd-stage juvenile Meloidogyne incognita (Kofoid and While) Chitwood. Harpacticoid copepods have not previously been reported as predators of phytoparasitic nematodes. Our tests indicate that nematodes may represent an important component of the diet of P. viguieri. The effect of P. viguieri on nematode populations in moist soils remains unknown.
Given the severity of the 2016 global bleaching event, there are major questions about how quickly reef communities will recover. Here, we explore the ecological and physical structural changes that occurred across five atoll interior reefs in the southern Maldives using data collected at 6 and 12 months post-bleaching. Following initial severe coral mortality, further minor coral mortality had occurred by 12 months post-bleaching, and coral cover is now low (<6%). In contrast, reef rugosity has continued to decline over time, and our observations suggest transitions to rubble-dominated states will occur in the near future. Juvenile coral densities in shallow fore-reef habitats are also exceptionally low (<6 individuals m⁻²), well below those measured 9–12 months following the 1998 bleaching event, and below recovery thresholds identified on other Indian Ocean reefs. Our findings suggest that the physical structure of these reefs will need to decline further before effective recruitment and recovery can begin.
Offshore coral reefs of the South China Sea are subject to complex overlapping sovereignty claims by up to six regional nations. Escalating tensions have led to widespread structural reinforcement of military outposts on many reefs via dredging and filling. Satellite images indicated at least 160 km² of coral reef damage, including 17 km² of essentially permanent damage from filling and channel/harbour dredging, and 143 km² of decadal-scale damage from dredging for building materials and giant clam harvesting. This damage will exacerbate the growing regional overfishing problem. Options to lessen tensions include (1) the establishment of a Greater Spratly Islands Peace Park, and (2) the collaborative management of fisheries, the environment and mineral resources across the entire Sea. Both options require freezes on extant claims and activities in support of claims. No matter how it is achieved, regional peace would greatly enhance fisheries stability and economic growth among all claimant nations. (freely available at https://maritimearchives.files.wordpress.com/2017/07/john-w-mcmanus-2017-offshore-coral-reef-damage-overfishing-and-paths-to-peace-in-the-south-china-sea-signed.pdf )
Ninety percent species of butterflies can be found in the tropics. Southeast Asia has one of the highest Lepidopteran biodiversity in the world, while over 1,200 species of butterflies reside in Malaysia. Despite high Lepidopteran diversity, there is still little knowledge on the butterfly distribution in the islands of Southeast Asia. The aim of this study was to generate species data for butterflies at the islands of Pulau Perhentian Besar and Pulau Bidong in Terengganu region, Malaysia. The collected data will be a foundation for long-term monitoring, future research and a species guideline for tourism. The faunistic composition of Rhopalocera was studied by using 20 baited traps in which 10 baited traps were set at the canopy level and another 10 baited traps were set in the understorey for seven days on each island. The baited traps at the understory and canopy level were set on selected trees at 1 m and 15 m above the ground respectively, and left to function from 0800 hours to 1700 hours. Ripe pineapples were used as bait to attract butterflies. Aerial netting along one kilometre of line transects were also conducted for catching butterflies. A total of 26 species of butterflies from four families were caught during the sampling period. Butterfly population on small islands may be particularly susceptible to environmental and stochastic changes. Thus, development and land clearing should be strictly controlled to prevent further loss of flora and fauna such as endangered tree species and endemic butterflies of the islands.
A taxonomic study was carried out based on the morphological and ultrastructure of a harpacticoid species M. hirsutus (Thompson & A. Scott, 1903) examined under a compound and scanning electron microscope (SEM). Samples were collected from the seaweed Padina sp. found on the intertidal zone of Bidong Island, Terengganu, Malaysia (5°37.3´N, 103°04´E) by washing them through a 42 microns net. Four females and 3 male were used for SEM. The only difference between the female of M. hirsutus and M.hirsutus bermudae is
the character of leg 5. Results obtained from scanning electron microscopy (SEM) studies showed that baseoendopod and exopod of M. hirsutus can be distinguished easily, the pictures never been previously reported for the species.
Animals from a wide range of taxonomic groups are capable of colour change, of which camouflage is one of the main functions. A considerable amount of past work on this subject has investigated species capable of extremely rapid colour change (in seconds). However, relatively slow colour change (over hours, days, weeks and months), as well as changes arising via developmental plasticity are probably more common than rapid changes, yet less studied. We discuss three key areas of colour change and camouflage. First, we review the mechanisms underpinning colour change and developmental plasticity for camouflage, including cellular processes, visual feedback, hormonal control and dietary factors. Second, we discuss the adaptive value of colour change for camouflage, including the use of different camouflage types. Third, we discuss the evolutionary–ecological implications of colour change for concealment, including what it can tell us about intraspecific colour diversity, morph-specific strategies, and matching to different environments and microhabitats. Throughout, we discuss key unresolved questions and present directions for future work, and highlight how colour change facilitates camouflage among habitats and arises when animals are faced with environmental changes occurring over a range of spatial and temporal scales.
This article is part of the themed issue ‘Animal coloration: production, perception, function and application’.
The composition of fatty acids in fishes can serve as trophic biomarkers in the analysis of marine food webs because fatty acids can be traced as essential dietary components to higher trophic levels; however, information on tropical coral fishes is scarce. In order to understand the feeding ecology of coral reef fish, fatty acid composition and levels were examined in the moon wrasse Thalassoma lunare collected in the Malaysian South China Sea. Fatty acid composition was predominantly saturated fatty acids (SAFA) (62.5%), followed by monounsaturated fatty acids (MUFA) (33.8%) and polyunsaturated fatty acids (PUFA) (3.7%). The most abundant fatty acids in SAFA, MUFA and PUFA were palmitic acid (C16: 0), oleic acid (C18: 1ω9c) and elaidic acid (C18: 1ω9t) and linolenic acid (C18: 3n3) and EPA (C20: 5n3), respectively. Fatty acid concentrations, especially in SAFA and MUFA, changed with fish growth, although PUFA did not change in fish growth. Such differences might be caused by differences in the diet of the fish accompanying the growth.
For broadcast spawning invertebrates such as the crown-of-thorns starfish, early life history stages (from spawning to settlement) may be exposed to a wide range of environmental conditions, and could have a major bearing on reproductive success and population replenishment. Arrested development in response to multiple environmental stressors at the earliest stages can be used to define lower and upper limits for normal development. Here, we compared sperm swimming speeds and proportion of motile sperm and rates of fertilization and early development under a range of environmental variables (temperature: 20–36 °C, salinity: 20–34 psu, and pH: 7.4–8.2) to identify environmental tipping points and thresholds for reproductive success. We also tested the effects of water-soluble compounds, derived from eggs, on sperm activity. Our results demonstrate that gametes, fertilization, and embryonic development are robust to a wide range of temperature, salinity, and pH levels that are outside the range found at the geographical limits of adult distribution and can tolerate environmental conditions that exceed expected anomalies as a result of climate change. Water-soluble compounds derived from eggs also enhanced sperm activity, particularly in environmental conditions where sperm motility was initially limited. These findings suggest that fertilization and embryonic development of crown-of-thorns starfish are tolerant to a wide range of environmental conditions, though environmental constraints on recruitment success may occur at later ontogenic stages.
A rapid assessment was conducted in Bako National Park (BNP), Kuching, Sarawak, Malaysian Borneo based on previous studies, published and unpublished reports. The habitat types in BNP can be classified into Kerangas forest, cliff vegetation, beach vegetation, mangrove forest, riverine (alluvial) forest and mixed dipterocarp forest. Up to date, a total of 224 species comprising 54 families and 18 orders of selected taxonomic groups (butterflies, amphibians, birds and mammals) in BNP were recorded throughout the study period in 2005 to presently. The highest number of species recorded was from class Insecta with relative abundance of 42.86% while class Aves showed the highest recorded number of families with relative abundance of 48.15%. The availability of good food resources, high forest structural and vegetation diversity were the major factors that could influence the density, relative abundance and diversity of faunal diversity in BNP. Periodical biodiversity monitoring of BNP is necessary in the face of potential poaching, local extinction and loss of buffer area to protect the integrity of the park. There are several gaps in our knowledge on the biodiversity of BNP that must be addressed in the near future.
Globally scleractinian corals are facing the threats of devastation due to anthropogenic activities as well as natural calamities. The concept of artificial reef was developed to increase the parallel reef areas along with the natural reef to strengthen marine biodiversity. The artificial reef ecosystem can be developed with the help of shipwrecks, abandoned tyres, cars etc. while the reef ball concept is the modern one to adapt. Andaman and Nicobar Islands is one of the biologically diverse areas with healthy number of scleractinian corals. Four shipwrecks scattered along the waters of these islands are serving as substratum for 125 species of scleractinian corals. North Bay shipwreck alone reported 114 species under 41 genera with the diversity (H') of 2.91. The studies on natural reef area showed 61% similarity in species content in comparison with the shipwrecks of North Bay region due to the proximity in location. The present study indicates that, shipwrecks serve as artificial substratum for the formation of coral reef with high diversity.
The Spratly Islands are a large group of more than 150 different coral formations from reefs to islands scattered between 6° and 12° N and 111° and 117° E in the southern part of the South China Sea. In addition to overfishing, dredging, and land reclamation in the area, an increased frequency of thermal anomalies resulting from global climate change has had an increasing effect on the coral reefs of the Spratly Islands. The coral surveys conducted in 2018–2019 on 15 sites within the archipelago revealed certain transformations of coral communities as a response to repetitive temperature stress. These transformations are expressed in shifts toward the dominance of thermally-resistant coral taxa with a stress-tolerant life strategy and in changes in size–frequency distribution of thermally-susceptible taxa toward the dominance of younger generations. Thermally-resistant taxa were dominant in 11 of 15 sites; eight of 15 sites were dominated by stress-tolerant taxa. The mean coral cover was 36.6%; the highest contribution in the total cover belonged to Acropora (27%), Porites (17.4%), and Pocillopora (4.1%). The high number of coral formations within the Spratly archipelago, high reef connectivity, and coral diversity determine the persistence of high reef resilience potential in the area.
The groundwater of Pulau Bidong, Terengganu, Malaysia was investigated to monitor the quality of freshwater source. Groundwater samples were collected from five sampling stations from June 2016 to October 2016. Physical parameters such as temperature, specific conductivity, dissolved oxygen (DO), pH, salinity, and DO saturation were measured in-situ by using handheld device. Meanwhile, total suspended solid (TSS), total dissolved solid (TDS), nitrate (NO3⁻), nitrite (NO2⁻), ammonium (NH4⁺) and phosphate (PO4³⁻) were also analysed. The inorganic nutrients of NO3⁻, NO2⁻, NH4⁺, and PO4³⁻ were ranged from 0.000 to 4.310 mg/L, 0.000–0.190 mg/L, 0.000–0.807 mg/L and 0.003–0.028 mg/L, respectively. The monthly trends of specific conductivity, DO, salinity, DO saturation, NH4, NO3 and NO2 demonstrated significant variation in June (the lowest rainfall) compared to other months. Correlation matrix revealed that temperature was associated with the specific conductivity, and NH4⁺ strongly correlated with DO, NO3⁻ and NO2⁻. Nevertheless, there is a strong negative correlation between physicochemical parameters and monthly rainfall distribution. The physicochemical parameters were within the recommended safe limits suggested by the World Health Organization (WHO) and National Drinking Water Quality Standard (NDWQS) except for pH. Nevertheless, pH of water does not directly impact on the human health. Environmetrics analysis demonstrated that NO3⁻ and PO4³⁻ significantly influenced the groundwater quality spatially. Furthermore, the temporal variation of groundwater quality was affected by pH and salinity. Overall, the groundwater sources from Pulau Bidong are considered safe to be used as drinking water. Notably, future studies are required for long-term monitoring to ensure the good quality of groundwaters from Pulau Bidong.
The other two respondents have carefully articulated many objections to David Imbroscio’s essay, responding to its arguments on its own terms. Rather than another point-by-point response, I offer a counternarrative that looks toward the future. In my view, ending exclusionary zoning (EZ) is an important element in a campaign to avoid some of the suffering low-income people in the United States will experience as the global climate emergency becomes increasingly acute, the national population ages, and the entrenched power of right-wing libertarians sustains inequality. Parochial actions like EZ will further complicate responses to these challenges. My response argues that for these reasons, Imbroscio’s essay is neither ethical nor logical.
Objects of anthropogenic origin submerged in the sea, such as shipwrecks, may induce significant environmental changes in their close proximity. There may be more than 100 000 shipwrecks in the Baltic Sea, however to date, their effects on biodiversity by the introduction of large hard substrates in this typically low-evenness, species-poor ecosystem have received little attention. This study compared separately macrobenthic assemblages found on three different objects (an old torpedo house, a former submarine and a minesweeper) lying at various depths (2–21 m) in Puck Bay (the Gulf of Gdańsk, Baltic Sea), and corresponding assemblages in soft sediments from their close (5 m away) and far vicinity (50 m away). A total of 26 taxa of macrobenthic algae, vascular plants and fauna were recorded. Nineteen species were found directly on the study objects. Nine species among them were only found on the submerged objects but none was substrate specific. At two locations clear differences in the assemblage structure between seabed in the close proximity of submerged objects and the seabed located farther apart were noted. Higher species richness, abundance and diversity (measured as Shannon-Wiener H′) was recorded only in the location of the deepest object. Its high similarity (both in terms of the assemblage structure and S, N, H’) with the closest neighbouring sediments may indicate a direct impact of the object on the surrounding seabed. The submerged objects generally supported a two - three times higher number of species and a ∼25 times higher number of individuals (but not diversity) than the soft bottom in the vicinity. The shallowest object lying within the euphotic zone hosted the most species rich (on avg. 10 species/144 cm²) and abundant (on avg. 379 ind./144 cm²) assemblages. Differences in the assemblage structure found between different objects are most likely associated with depth related environmental variables. The results of the study can serve as a baseline for future investigations and for evaluation of local ecological effects of the artificial reef concepts, breakwaters and offshore wind farms.
Increasing emissions of CO 2 and the resultant ocean acidification (OA) will have large implications for the marine ecosystems sustained by habitat-forming species and their related ecosystem services (ES), with potentially significant impacts on human well-being. Here, we provide an assessment of the direct and indirect impacts of OA on ES. The changes in the functioning of coralligenous reefs and Posidonia oceanica meadows promoted by OA were investigated by i) synthesizing current knowledge into conceptual models. The models were then used to, ii) assessing the impacts of exposure of the selected taxa at the acidification level associated with two CO 2 emission scenarios and iii) using the conceptual model outputs to project the cascading impacts from individuals to functions to ES. The results highlight that the combination of the direct and indirect effects of acidification will alter many functions of both coralligenous and P.oceanica systems, triggering habitat modifications and the loss of highly valuable ES. While the exact timing of the expected changes will depend on the severity of the emission scenarios, significant and hardly reversible changes can be expected as quickly as a few decades under the business-as-usual scenario, and many ecosystem services are at risk even under much more conservative scenarios.
Coral reefs in the Ryukyu Islands, southern Japan, have been undergoing degradation for at least five decades. Recently, the archipelago has been hit by bleaching events for two consecutive years (summers of 2016–2017). Shallow coral communities have been reported as especially affected. In this study, using underwater transects, we assessed the status of shallow coral reef communities in Kume Island, at seven distinct locations in Shimajiri Bay, following reports from local fishermen and divers of heavy bleaching across the bay. Our data and analyses revealed that the benthic environment in the bay has algae as the main component, with an average coral cover of only 7.2%. Branching coral colonies, which used to be the most common morphology in Kume Island reefs, accounted for just 7.6% of the total coral cover. Notably, the genus Acropora was almost completely absent from our transects, although its recent presence was confirmed by dead colonies making up 4.12% of total transect coverage, suggesting that restoration efforts focused on this genus might be possible in the future. In order for these to be successful, however, a better understanding of the environmental situation at Kume Island is required, including the effects of human activities on coral reef communities.
The contamination of heavy metals in sediments of the Three Gorges Reservoir (TGR) is increasingly concerned as a major issue for water quality since the full impoundment. In this study, the sediment profiles in the riparian and submerged areas from Fuling to Zigui in the middle-low TGR mainstream were collected to investigate the stratified distribution of heavy metals (Cd, Cr, Cu, Ni, Pb and Zn) and assess their contamination and potential eco-risk. The results showed that the concentrations of these metals in the riparian sediments did not present a marked spatial trend except the concentrations of Cd that increased towards the dam. However, the metal concentrations (except Cd) in the submerged sediments were generally higher near the dam. The concentrations of heavy metals in the riparian sediments did not show marked vertical variation, while in the submerged sediments they fluctuated dramatically with depth, indicating the metal accumulation processes in last few years. Sediment grain sizes as an indicator of hydrodynamic regimes dominated the vertical distribution of heavy metals over organic matters and Fe/Mn oxide/hydroxides. The sediments from both riparian and submerged areas of the TGR were contaminated by anthropogenic metals of Cd, Cu and Pb that were mainly from the ore mining, fossil fuel combustion, agricultural pollution and atmospheric deposition. Cadmium was a major metal pollutant in the sediments with a high contamination and potential eco-risk level. The results of this study indicate that the sorting of sediments with the anti-seasonal flow regulation determines the spatial and temporal distribution of heavy metal contamination in the sediments, and the impoundment stages of the TGR in history regulate the accumulation processes of the metals.
The aim of the present study was to investigate the effects of water temperature and pH on total suspended solids (TSS) tolerance of a native fish species, Barbonymus schwanenfeldii (Bleeker, 1854) and an exotic fish species, Oreochromis niloticus (Linnaeus, 1758) in Malaysia. The survival rates of both juvenile fish were tested in different TSS concentrations (0, 500, 1000, and 5000 mg L⁻¹) at two water temperatures (27 and 29 °C) and three water pH (pH 5, 6, and 7) for 21 days. The results showed that biotic and abiotic factors significantly influenced fish survival rate. The survival rate of juvenile fish significantly (p < 0.05) decreased when they were exposed to warm and low pH water and high suspended solids. Moreover, the TSS tolerances of both juvenile fish in term of survivorship exacerbated at warm and low pH water. The O. niloticus juveniles were significantly (p < 0.05) more tolerant to low water pH and high TSS than the B. schwanenfeldii juveniles. Nevertheless, the warmer water did not affect survival rate of B. schwanenfeldii juveniles significantly (p < 0.05) more than that of O. niloticus juveniles. The present study demonstrated the potential negative impacts of water quality deterioration and biological invasion on the survival of Malaysian native fish in natural environment.
Estuarine acidification and carbonate chemistry derive from multiple biogeochemical processes. Other than biogenic CO2-acidification, estuaries can be acidified allochthonously through non-carbonate sources originating in freshwater and land ecosystems. The present study considered the carbonate chemistry of a nutrified, turbid, tropical mangrove estuary, influenced by acidic groundwater discharge from pyritic soils (Acid Sulphate Soils, ASS). We studied the spatial and temporal variation of the surface water pH, salinity, total alkalinity (TA), partial pressure carbon dioxide (pCO2), dissolved inorganic carbon (DIC), and calcite (Ωcal) and aragonite (Ωara) saturation, in the Brunei Estuarine System (BES), Borneo, Southeast Asia. pH and salinity for tidal to seasonal timeframes were determined from data collected half-hourly, logged at three stations (upper, middle and lower estuary); these data were correlated with rainfall incidence and intensity. Carbonate parameters were calculated from TA using discrete samples collected from six stations. pH (6.8–7.9) and salinity (4.2–28.2) increased expectedly seawards, due to tidal forcing and freshwater dilution at opposite ends of the estuary; amplitudes within a tidal cycle became expanded landwards and during spring tides. While, the overall effect of heavy daily downpours on estuarine salinity and pH was muted, cumulative rainfall during the monsoon season distinctly lowered parameter baselines; the response was again more pronounced in the upper estuary. In the mid-to-upper estuary, we observed a remarkably low pH relative to salinity, extraordinary pCO2super-saturation (13031 ± 4412 μatm) and carbonate undersaturation (Ωcal and Ωara were 0.006–1.431 and 0.004–0.928, respectively). Although the relative contributions of heterotrophic metabolism and ASS-discharge to the estuarine pH and pCO2 were not determined, both processes are implicated in increasing both acidity and CO2 levels. This study contributes to the understanding of carbonate fluxes in mineral-acidified estuaries.
Monitoring of macroinvertebrate communities is frequently used to define the ecological health status of rivers. Ideally, biomonitoring should also give an indication on the major stressors acting on the macroinvertebrate communities supporting the selection of appropriate management measures. However, most indices are affected by more than one stressor. Biological traits (e.g. size, generation time, reproduction) could potentially lead to more stressor-specific indices. However, such an approach has rarely been tested.
In this study we classify 324 macroinvertebrate taxa as vulnerable (decreasing abundances) or tolerant (increasing abundances) along 21 environmental gradients (i.e. nutrients, major ions, oxygen and micropollutants) from 422 monitoring sites in Germany using Threshold Indicator Taxa Analysis (TITAN). Subsequently, we investigate which biological traits and taxonomic groups are associated with taxa classified as vulnerable or tolerant with regard to specific gradients.
The response of most taxa towards different gradients was similar and especially high for correlated gradients. Traits associated with vulnerable taxa across most gradients included: larval aquatic life stages, isolated cemented eggs, reproductive cycle per year < 1, scrapers, aerial and aquatic active dispersal and plastron respiration. Traits associated with tolerant taxa included: adult aquatic life stages, polyvoltinism, ovoviviparity or egg clutches in vegetation, food preference for dead animals or living microinvertebrates, substrate preference for macrophytes, microphytes, silt or mud and a body size > 2–4 cm.
Our results question whether stressor-specific indices based on macroinvertebrate assemblages can be achieved using single traits, because we observed that similar taxa responded to different gradients and also similar traits were associated with vulnerable and tolerant taxa across a variety of water quality gradients. Future studies should examine whether combinations of traits focusing on specific taxonomic groups achieve higher stressor specificity.
A study had been carried out to determine Cu, Zn, Cd, Hg and Pb concentrations in the muscle and fins of four elasmobranchs species namely spot-tail sharks, milk sharks, whitespotted bamboo sharks and whitespotted guitarfish from Pulau Kambing LKIM Fishery Complex, Kuala Terengganu, Malaysia. Zinc level was found to have the highest concentration whereas Cd had the lowest concentration in both organs. By comparing both organs, metals concentrations in fins of all elasmobranchs species were higher than muscle. Result obtained was compared with the guidelines set by Malaysian Food Regulation and the provisional tolerable weekly intake was also determined. Current study recommends that the muscle of whitespotted bamboo shark from Kuala Terengganu Waters is likely not to be consumed due to it exceeded the allowable consumption guideline. Finding of this paper is very useful as it provides the baseline data on the pollution status of elasmobranchs in Kuala Terengganu Waters.
To further understand dissolved carbon dioxide (CO2) dynamics and the link between surface productivity and carbon content in the sediments of the Sulu Sea, seawater samples were obtained from high and low productivity areas during the northeast monsoon of December 2007/January 2008, which also corresponded to a period of weak La Niña. CO2 concentrations in surface waters of the Sulu Sea are mostly governed by productivity, while sub-surface CO2 concentrations are influenced by physical processes including vertical mixing and bottom-intensified flow southwest of Mindoro and Panay Straits (central Philippines), and upwelling off the west coast of Zamboanga in Mindanao (south Philippines). These physical processes are manifested in the downward sloping isolines of carbonate parameters near the straits and weak upwelling of waters saturated with respect to atmospheric CO2. Deep waters ventilated from the Sulu Sea have lower dissolved inorganic carbon (DIC) and total alkalinity (TA), and higher pHT (pH in the total scale) and carbonate ion concentrations (CO3²⁻) than the deep waters of the South China Sea. Nevertheless, TA in the deep waters of the Sulu Sea increases below 2000m at almost twice the rate as DIC, suggesting possible dissolution of sedimentary CaCO3. A small positive "excess" alkalinity signal is observed in the South China Sea but negative values in the Sulu Sea may reflect the possible contribution of organic acids. This study suggests that the upwelling area within the Sulu Sea, albeit limited in size, could be a source of CO2 to the atmosphere especially during the stronger northeast monsoon periods. Other processes such as dissolution of CaCO3 in the sediments and possible organic acidity should be considered in understanding the Sulu Sea's CO2 sink capacity for the coming years.
Ocean acidification (OA), attributed to the sequestration of atmospheric carbon dioxide (CO2) into the surface ocean, and coastal eutrophication, attributed in part to land-use change and terrestrial runoff of fertilizers, have received recent attention in an experimental framework examining the effects of each on coral reef net ecosystem calcification (Gnet). However, OA and eutrophication in conjunction have yet to receive attention from the perspective of coral reef sediment dissolution. To address this omission, CO2 and nitrate (NO3⁻) addition experiments were performed in Mo'orea, French Polynesia. Incubation chambers were used to measure sediment Gnet during the day and night under three different [NO3⁻] (0, 9.8, and 19.7 μM) that were nested within four separate constructed coral reef communities maintained at different PCO2 levels (417, 721, 1030, and 1333 μatm, respectively). PCO2 negatively affected sediment Gnet during the day and night, resulting in a shift to diel net dissolution at a PCO2 of 1030 μatm. Elevated NO3⁻ alone, and the combination of NO3⁻ and PCO2, both negatively affected sediment Gnet at night. However, the response of Gnet to NO3⁻ was less clear during the day, where diurnal sediment Gnet was enhanced under the combined treatment of elevated NO3⁻ and PCO2, resulting in no net effect of NO3⁻ on sediment Gnet on diel timescales. Overall, these results show that ocean acidification represents a greater threat to the balance of calcification and dissolution in Mo'orea's back reef sediment communities than the potential impact of NO3⁻ enrichment on relatively short timescales.
