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Mazlan Abd Ghaffar - One of the best experts on this subject based on the ideXlab platform.
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Spatial and Temporal Variations in Strombus canarium (Gastropoda: Strombidae) Abundance at Merambong Seagrass Bed, Malaysia (Variasi Reruang dan Temporal bagi Kelimpahan Strombus canarium (Gastropoda: Strombidae)
2016Co-Authors: Sains Malaysiana, Zaidi Che Cob, Aziz Arshad, Japar Sidik Bujang, Di Hamparan Rumput Laut Merambong, Mazlan Abd GhaffarAbstract:The abundance of Marine Benthic Organisms often exhibits distinct distributional patterns, which is generally governed by many physical and biological factors specific to the habitat. In this study, the spatial and temporal variations in abundance of the dog conch, Strombus canarium Linnaeus 1758, a commercially important Marine gastropod, was investigated. Assessment of conch abundance at Merambong seagrass bed, Malaysia, was conducted using a transect belt method. Sampling stations were randomly selected and environmental parameters associated with the habitat were recorded. The species showed distinct spatial distributional pattern. Conch densities were significantly higher in sheltered areas, mainly in mixed seagrass bed dominated by Halophila spp. and with high sediment organic content. The densities were relatively very low in areas dominated by the tape seagrass, Enhalus acoroides. The species studied also showed distinct temporal variation in abundance. The abundance value was seasonally varied with highest density recorded during the wet monsoon season (p<0.05). The densities were otherwise very low during the dry season, except for a slight peak in July. Since the conch is a very important fishery species within the Johor Straits and regulations on their harvesting is still lacking, this information would be very important for their sustainable management
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spatial and temporal variations in strombus canarium gastropoda strombidae abundance at merambong seagrass bed malaysia
Sains Malaysiana, 2014Co-Authors: Zaidi Che Cob, Aziz Arshad, Japar Sidik Bujang, Mazlan Abd GhaffarAbstract:The abundance of Marine Benthic Organisms often exhibits distinct distributional patterns, which is generally governed by many physical and biological factors specific to the habitat. In this study, the spatial and temporal variations in abundance of the dog conch, Strombus canarium Linnaeus 1758, a commercially important Marine gastropod, was investigated. Assessment of conch abundance at Merambong seagrass bed, Malaysia, was conducted using a transect belt method. Sampling stations were randomly selected and environmental parameters associated with the habitat were recorded. The species showed distinct spatial distributional pattern. Conch densities were significantly higher in sheltered areas, mainly in mixed seagrass bed dominated by Halophila spp. and with high sediment organic content. The densities were relatively very low in areas dominated by the tape seagrass, Enhalus acoroides. The species studied also showed distinct temporal variation in abundance. The abundance value was seasonally varied with highest density recorded during the wet monsoon season (p<0.05). The densities were otherwise very low during the dry season, except for a slight peak in July. Since the conch is a very important fishery species within the Johor Straits and regulations on their harvesting is still lacking, this information would be very important for their sustainable management.
Carlos M Duarte - One of the best experts on this subject based on the ideXlab platform.
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effects of global warming on thresholds of hypoxia for Marine Benthic Organisms
2011Co-Authors: Raquel Vaquersunyer, Carlos M DuarteAbstract:Trabajo presentado en la EUR-OCEANS Conference - Ocean deoxygenation and implications for Marine biogeochemical cycles and ecosystems, celebrada en Toulouse, Francia, del 24 al 26 de 2011
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temperature effects on oxygen thresholds for hypoxia in Marine Benthic Organisms
Global Change Biology, 2011Co-Authors: Raquel Vaquersunyer, Carlos M DuarteAbstract:This research is a contribution to the ‘Water bodies in Europe: Integrative Systems to assess Ecological status and Recovery (WISER)’ project, funded by FP7 (contract number #226273) and project MEDEICG, funded by the Spanish Ministry of Science and Innovation (number CTM2009-07013). We thank A. Steckbauer for help with translations of German papers. C. M. D. was supported by a sabbatical fellowship from the Spanish Ministry of Education
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thresholds of hypoxia for Marine biodiversity
Proceedings of the National Academy of Sciences of the United States of America, 2008Co-Authors: Raquel Vaquersunyer, Carlos M DuarteAbstract:Hypoxia is a mounting problem affecting the world’s coastal waters, with severe consequences for Marine life, including death and catastrophic changes. Hypoxia is forecast to increase owing to the combined effects of the continued spread of coastal eutrophication and global warming. A broad comparative analysis across a range of contrasting Marine Benthic Organisms showed that hypoxia thresholds vary greatly across Marine Benthic Organisms and that the conventional definition of 2 mg O2/liter to designate waters as hypoxic is below the empirical sublethal and lethal O2 thresholds for half of the species tested. These results imply that the number and area of coastal ecosystems affected by hypoxia and the future extent of hypoxia impacts on Marine life have been generally underestimated. Benthic community oxygen coastal ecosystems eutrophication impacts D issolved oxygen in coastal waters has changed drastically over the past decades, arguably more so than any other ecologically important variable (1, 2), leading to the widespread occurrence of hypoxia. An assessment of the literature shows that the number of coastal sites where hypoxia has been reported has increased with an exponential growth rate of 5.54% year 1 over time [Fig. 1 and supporting information (SI) Table S1]. Although this growth rate can be partially attributed to an increased observational effort, increasing the number of costal ecosystems monitored and the likelihood of detecting hypoxia therein, this growth also reflects an increase in the prevalence of hypoxia in different types of coastal ecosystems. Multiple reports from careful monitoring time series provide evidence for an unambiguous increase in the number of hypoxic zones and their extension, severity, and duration (3–6). This growth is expected to continue because the prevalence of hypoxia is forecast to increase further owing to the combined effects of eutrophication, leading to the excessive production of organic matter that increases the oxygen demand of coastal ecosystems (7), and the increase in temperature caused by climate change, which enhances the respiratory oxygen demand of the Organisms (8), reduces oxygen solubility (9), and reduces the ventilation of coastal waters by affecting stratification patterns (10).
Elizabeth J Durhan - One of the best experts on this subject based on the ideXlab platform.
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check studies with hyalella azteca and chironomus tentans in support of the development of a sediment quality criterion for dieldrin
Environmental Toxicology and Chemistry, 1995Co-Authors: Robert A Hoke, Patricia A Kosian, Anne M Cotter, Frances M Van Dermeiden, Gerald T Ankley, Gary L Phipps, Elizabeth J DurhanAbstract:The development of sediment quality criteria (SQCs) for nonpolar compounds using equilibrium partitioning theory (EqP) requires three critical data elements for the compound of interest: (a) a reliable, measured K ow ; (b) an acceptable minimum data set for the development of the final acute and final chronic values necessary to calculate a water-quality criterion (WQC); and (c) «check» experiments with appropriate freshwater and Marine Benthic Organisms to ensure that their responses in spiked-sediment tests are in agreement with responses predicted based on EqP. This study presents the results of dieldrin check experiments with two freshwater species: the amphipod Hyalella azteca and the chironomid Chironomus tentans. Ten-day, flowthrough, water-only dieldrin LC50 values for the amphipod and chironomid were 7.6 and 1.1 μg/L, respectively. The LC50 values for the two species based on organic carbon-normalized sediment concentrations of dieldrin were generally less variable than values based on dieldrin concentrations in sediments on a dry-weight basis. Ten-day LC50 values for H. azteca and C. tentans based on measured pore-water concentrations of dieldrin were greater than those based on EqP-predicted pore-water concentrations of dieldrin. An increase in the apparent water solubility of dieldrin as a result of binding to dissolved organic carbon appeared to account for this phenomenon. Ten-day LC50 values for H. azteca and C. tentans based on EqP-predicted pore-water concentrations of dieldrin were within a factor of 25 and 3 of their respective 10-d, water-only dieldrin LC50 values. Avoidance of the dieldrin-spiked sediments may offer a partial explanation for the concentration-response results observed with H. azteca and the greater difference observed for this species between water-only and predicted pore-water 10-d LC50 values for dieldrin. Inhibition of growth in C. tentans was also a sensitive end point with effects observed at pore-water concentrations of dieldrin as small as 5.5 μg/g organic carbon. Based on these results, it appears that EqP based upon sediment organic carbon content is an appropriate model for converting WQC for dieldrin to SQC. These results also highlight the importance of using multiple Benthic test species (including at least one infaunal species), end points, and sediments in SQC sediment-spiking check studies
Krasnobaev Artem - One of the best experts on this subject based on the ideXlab platform.
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Quantification and modelling of Fluxes of persistent organic pollutants (POPs) to Antarctic Marine Benthic Organisms
Wageningen University, 2020Co-Authors: Krasnobaev ArtemAbstract:Marine Benthic ecosystems are considered to be the final sink of persistent organic pollutants (POPs). Antarctica is a global net receptor of POPs, therefore, quantification of fluxes of POPs to and in the Antarctic Benthic ecosystems, although practically difficult, is essential to understand the overall dynamics of these contaminants on a global scale. In order to achieve that, Antarctic Benthic ecosystems were studied as an integral part of the Antarctic environment as a whole. Furthermore, robust quality assurance and reporting practices are needed to establish comprehensive time trends of these pollutants, especially due to their expected relatively low concentrations. Current thesis was one of the first attempts to assess fluxes of POPs to Benthic Antarctic ecosystems. The major outcome of the study is the conformation of the hypothesis on potentially increasing concentrations of POPs in the Benthic ecosystems. Simultaneously, the concentrations of POPs in the pelagic ecosystems may have also stopped decreasing, which was previously indicated. Nevertheless, the fluxes of POPs and, possibly, their toxicological effects on the Antarctic Benthic animals will undergo considerable changes in the future due to global change, which must be researched further in detail
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Legacy and Emerging Persistent Organic Pollutants in Antarctic Benthic Invertebrates near Rothera Point, Western Antarctic Peninsula
2020Co-Authors: Krasnobaev Artem, Dam, Guillaume Ten, Boerrigter-eenling Rita, Peng Fang, Leeuwen, Stefan P.j. Van, Morley, Simon A., Peck, Lloyd S., Brink, Nico W. Van DenAbstract:Pollutant levels in polar regions are gaining progressively more attention from the scientific community. This is especially so for pollutants that persist in the environment and can reach polar latitudes via a wide range of routes, such as some persistent organic pollutants (POPs). In this study, samples of Antarctic Marine Benthic Organisms were analyzed for legacy and emerging POPs (polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), and organochlorine pesticides) to comprehensively assess their current POP concentrations and infer the potential sources of the pollutants. Specimens of five Benthic invertebrate species were collected at two distinct locations near Rothera research station on the Antarctic Peninsula (67°35'8 ̋ S and 68°7'59 ̋ W). Any impact of the nearby Rothera station as a local source of pollution appeared to be negligible. The most abundant chemicals detected were hexachlorobenzene (HCB) and BDE-209. The highest concentrations detected were in limpets and sea urchins, followed by sea stars, ascidians, and sea cucumbers. The relative congener patterns of PCBs and PBDEs were similar in all of the species. Some chemicals (e.g., heptachlor, oxychlordane, and mirex) were detected in the Antarctic invertebrates for the first time. Statistical analyses revealed that the distribution of the POPs was not only driven by the feeding traits of the species but also by the physicochemical properties of the specific compounds.
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Legacy and Emerging Persistent Organic Pollutants in Antarctic Benthic Invertebrates near Rothera Point, Western Antarctic Peninsula
'American Chemical Society (ACS)', 2020Co-Authors: Krasnobaev Artem, Boerrigter-eenling Rita, Ten Dam Guillaume, Peng Fengjiao, Van Leeuwen Stefan, Morley Simon, Peck Lloyd, Van Den Brink, Nico W.Abstract:The levels of pollutants in polar regions is gaining progressively more attention from the science community. This is especially so for pollutants that persist in the environment and can reach polar latitudes via a wide range of routes, such as persistent organic pollutants (POPs). In this study samples of Antarctic Marine Benthic Organisms were analysed for legacy and emerging POPs to comprehensively assess the current POPs concentrations in Antarctic benthos and infer the potential sources of the pollutants. Specimens of 5 different Benthic invertebrate species were collected in 2 distinct locations near the Rothera Research station (67°35'8"S and 68°7'59"W). Any impact of the nearby Rothera Station as a local source of pollution appeared to be negligible. The most abundant chemicals detected were HCB and BDE-209, reaching the highest concentrations in limpets and urchins, followed by sea stars, ascidians and sea cucumbers. The relative congener patterns of PCBs and PBDEs were almost the same in all species. Some chemicals (e.g. Heptachlor, Oxychlordane and Mirex) were detected in the Antarctic invertebrates for the first time. Statistical methods revealed that the distribution of the POPs is not only driven by the feeding traits of the species, but also by the physico-chemical properties of the individual compounds. Benthic invertebrates are excellent indicators of the contaminant patterns of inshore Antarctic ecosystems
Raquel Vaquersunyer - One of the best experts on this subject based on the ideXlab platform.
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effects of global warming on thresholds of hypoxia for Marine Benthic Organisms
2011Co-Authors: Raquel Vaquersunyer, Carlos M DuarteAbstract:Trabajo presentado en la EUR-OCEANS Conference - Ocean deoxygenation and implications for Marine biogeochemical cycles and ecosystems, celebrada en Toulouse, Francia, del 24 al 26 de 2011
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temperature effects on oxygen thresholds for hypoxia in Marine Benthic Organisms
Global Change Biology, 2011Co-Authors: Raquel Vaquersunyer, Carlos M DuarteAbstract:This research is a contribution to the ‘Water bodies in Europe: Integrative Systems to assess Ecological status and Recovery (WISER)’ project, funded by FP7 (contract number #226273) and project MEDEICG, funded by the Spanish Ministry of Science and Innovation (number CTM2009-07013). We thank A. Steckbauer for help with translations of German papers. C. M. D. was supported by a sabbatical fellowship from the Spanish Ministry of Education
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thresholds of hypoxia for Marine biodiversity
Proceedings of the National Academy of Sciences of the United States of America, 2008Co-Authors: Raquel Vaquersunyer, Carlos M DuarteAbstract:Hypoxia is a mounting problem affecting the world’s coastal waters, with severe consequences for Marine life, including death and catastrophic changes. Hypoxia is forecast to increase owing to the combined effects of the continued spread of coastal eutrophication and global warming. A broad comparative analysis across a range of contrasting Marine Benthic Organisms showed that hypoxia thresholds vary greatly across Marine Benthic Organisms and that the conventional definition of 2 mg O2/liter to designate waters as hypoxic is below the empirical sublethal and lethal O2 thresholds for half of the species tested. These results imply that the number and area of coastal ecosystems affected by hypoxia and the future extent of hypoxia impacts on Marine life have been generally underestimated. Benthic community oxygen coastal ecosystems eutrophication impacts D issolved oxygen in coastal waters has changed drastically over the past decades, arguably more so than any other ecologically important variable (1, 2), leading to the widespread occurrence of hypoxia. An assessment of the literature shows that the number of coastal sites where hypoxia has been reported has increased with an exponential growth rate of 5.54% year 1 over time [Fig. 1 and supporting information (SI) Table S1]. Although this growth rate can be partially attributed to an increased observational effort, increasing the number of costal ecosystems monitored and the likelihood of detecting hypoxia therein, this growth also reflects an increase in the prevalence of hypoxia in different types of coastal ecosystems. Multiple reports from careful monitoring time series provide evidence for an unambiguous increase in the number of hypoxic zones and their extension, severity, and duration (3–6). This growth is expected to continue because the prevalence of hypoxia is forecast to increase further owing to the combined effects of eutrophication, leading to the excessive production of organic matter that increases the oxygen demand of coastal ecosystems (7), and the increase in temperature caused by climate change, which enhances the respiratory oxygen demand of the Organisms (8), reduces oxygen solubility (9), and reduces the ventilation of coastal waters by affecting stratification patterns (10).