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Ocean acidification increases larval swimming speed and has limited effects on spawning and settlement of a robust fouling bryozoan, Bugula neritina Полный текст
2017
Pecquet, Antoine | Dorey, Narimane | Chan, Kit Yu Karen
Ocean acidification increases larval swimming speed and has limited effects on spawning and settlement of a robust fouling bryozoan, Bugula neritina Полный текст
2017
Pecquet, Antoine | Dorey, Narimane | Chan, Kit Yu Karen
Few studies to date have investigated the effects of ocean acidification on non-reef forming marine invertebrates with non-feeding larvae. Here, we exposed adults of the bryozoan Bugula neritina and their larvae to lowered pH. We monitored spawning, larval swimming, settlement, and post-settlement individual sizes at two pHs (7.9 vs. 7.6) and settlement dynamics alone over a broader pH range (8.0 down to 6.5). Our results show that spawning was not affected by adult exposure (48h at pH7.6), larvae swam 32% faster and the newly-settled individuals grew significantly larger (5%) at pH7.6 than in the control. Although larvae required more time to settle when pH was lowered, reduced pH was not lethal, even down to pH6.5. Overall, this fouling species appeared to be robust to acidification, and yet, indirect effects such as prolonging the pelagic larval duration could increase predation risk, and might negatively impact population dynamics.
Показать больше [+] Меньше [-]Seawater carbonate chemistry and larval swimming speed, spawning and settlement of a robust fouling bryozoan, Bugula neritina Полный текст
2017
Pecquet, Antoine | Dorey, Narimane | Chan, Kit Yu Karen
Few studies to date have investigated the effects of ocean acidification on non-reef forming marine invertebrates with non-feeding larvae. Here, we exposed adults of the bryozoan Bugula neritina and their larvae to lowered pH. We monitored spawning, larval swimming, settlement, and post-settlement individual sizes at two pHs (7.9 vs. 7.6) and settlement dynamics alone over a broader pH range (8.0 down to 6.5). Our results show that spawning was not affected by adult exposure (48 h at pH 7.6), larvae swam 32% faster and the newly-settled individuals grew significantly larger (5%) at pH 7.6 than in the control. Although larvae required more time to settle when pH was lowered, reduced pH was not lethal, even down to pH 6.5. Overall, this fouling species appeared to be robust to acidification, and yet, indirect effects such as prolonging the pelagic larval duration could increase predation risk, and might negatively impact population dynamics.
Показать больше [+] Меньше [-]Response of the pearl oyster Pinctada margaritifera to cadmium and chromium: Identification of molecular biomarkers Полный текст
2017
Gueguen, Yannick | Denis, Saulnier | Adrien, Santini | Kevin, Magre | Pierre, Garen | Solène, Bernagout | Marine, Nohl | Patrick, Bouisset | Herehia, Helme | Serge, Planes | Gilles, Le Moullac
Response of the pearl oyster Pinctada margaritifera to cadmium and chromium: Identification of molecular biomarkers Полный текст
2017
Gueguen, Yannick | Denis, Saulnier | Adrien, Santini | Kevin, Magre | Pierre, Garen | Solène, Bernagout | Marine, Nohl | Patrick, Bouisset | Herehia, Helme | Serge, Planes | Gilles, Le Moullac
This study was designed to identify in the pearl oyster Pinctada margaritifera, used as a bio-accumulator, molecular biomarkers for the presence of heavy metals in the lagoon environment. Pearl oysters were exposed to 2 concentrations (1 and 10μgL−1) of cadmium (Cd) and chromium (Cr) compared to a control. Twelve target genes encoding proteins potentially involved in the response to heavy metal contamination with antioxidant, detoxification or apoptosis activities were selected. P. margaritifera accumulated Cd but not Cr, and mortality was related to the amount of Cd accumulated in tissues. In response to Cd-Cr contamination, metallothionein (MT) was significantly up-regulated by Cd-Cr at both concentrations, while 7 others (SOD, CAT, GPX, GSTO, GSTM, CASP, MDR) were down-regulated. Based on the development of these molecular tools, we propose that the pearl oyster, P. margaritifera, could be used as a sentinel species for heavy metal contamination in the lagoons of tropical ecosystems.
Показать больше [+] Меньше [-]Response of the pearl oyster Pinctada margaritifera to cadmium and chromium: Identification of molecular biomarkers Полный текст
2017
Gueguen, Yannick | Saulnier, Denis | Santini, Adrien | Magre, Kevin | Garen, Pierre | Bernagout, Solene | Nohl, Marine | Bouisset, Patrick | Helme, Herehia | Planes, Serge | Le Moullac, Gilles
This study was designed to identify in the pearl oyster Pinctada margaritifera, used as a bio-accumulator, molecular biomarkers for the presence of heavy metals in the lagoon environment. Pearl oysters were exposed to 2 concentrations (1 and 10 μg L− 1) of cadmium (Cd) and chromium (Cr) compared to a control. Twelve target genes encoding proteins potentially involved in the response to heavy metal contamination with antioxidant, detoxification or apoptosis activities were selected. P. margaritifera accumulated Cd but not Cr, and mortality was related to the amount of Cd accumulated in tissues. In response to Cd-Cr contamination, metallothionein (MT) was significantly up-regulated by Cd-Cr at both concentrations, while 7 others (SOD, CAT, GPX, GSTO, GSTM, CASP, MDR) were down-regulated. Based on the development of these molecular tools, we propose that the pearl oyster, P. margaritifera, could be used as a sentinel species for heavy metal contamination in the lagoons of tropical ecosystems.
Показать больше [+] Меньше [-]Fine sediments suppress detritivory on coral reefs Полный текст
2017
Tebbett, Sterling B. | Goatley, Christopher H.R. | Bellwood, David R.
Increasing sediment inputs are recognised as an important factor leading to coral reef degradation. However, the role of sediments in ecological processes is poorly understood. This study used paired-choice trials to quantify the effects of sediment grain size and chemical composition on feeding by the abundant detritivorous reef fish, Ctenochaetus striatus. The size of sediments from algal turfs were also compared to those ingested by reef-dwelling C. striatus. Algal turfs containing coarser sediments were preferred by C. striatus, while sediment composition (reefal carbonates vs. riverine silicates) had little effect. On the reef, C. striatus ingested finer sediments than those present in algal turfs. C. striatus appears to prefer algal turfs with coarser sediments as this facilitates ingestion of fine detrital particles, while finer sediments prevent selective feeding on detritus. These findings suggest that fine sediments from terrestrial runoff or dredging may be detrimental to feeding by detritivorous species.
Показать больше [+] Меньше [-]Sources of bathing water pollution in northern Tuscany (Italy): Effects of meteorological variables Полный текст
2017
Federigi, Ileana | Verani, Marco | Carducci, Annalaura
This study was carried out in a popular tourist destination located in Italy, where short-term pollution posed the problem of low quality status of bathing waters (according to European Directive) owing to the fecal contamination caused by drainage ditches. Our goal was to understand the role of meteorological conditions on freshwater and seawater bacterial indicator levels, and the impact of polluted streams on seawater contamination. To this aim, results from surface waters were analyzed during five bathing seasons, from 2011 to 2015. Our results demonstrated a relationship between bacterial densities and rainfall amount and a time-dependent dilution effect of the sea between the two halves of each bathing season. This analytical survey confirmed the strategic role of meteorological variables in bathing waters quality, and it could be a support for generation and development of predicting models of indicator levels for bathing area.
Показать больше [+] Меньше [-]Freshwater lenses as ecological and population sustenance, case study in the coastal wetland of Samborombón Bay (Argentina) Полный текст
2017
Tanjal, Carolina | Carol, Eleonora | Richiano, Sebastián | Santucci, Lucia
Freshwater lenses associated to shell ridges and sand sheets exist on the coastal wetland of Samborombón Bay. As they constitute one of the most vulnerable aquifer systems, it is the aim of this study to determine the hydrogeochemical processes that condition the chemical quality of its groundwater and to assess their present and future capability as sustenance of native woods and local villagers. To achieve this, hydrogeomorphological field surveys were made and groundwater samples were taken. Results show that lenses have a mean thickness of 12m and its chemical quality depends on the dissolution of CO2(g) and carbonates, weathering of silicates and ion exchange. Lenses can be affected by long-term climatic variability and mining. The study of morphology and geochemistry of the freshwater lenses bring lights into important information about the management of water resources and conservation of the environment.
Показать больше [+] Меньше [-]Elemental distribution and trace metal contamination in the surface sediment of south east coast of India Полный текст
2017
Kumar, S Barath | Padhi, R.K. | Mohanty, A.K. | Satpathy, K.K.
Spatial distribution and potential ecological risk of trace metals in the surface sediment of south east coast of India covering eight different ecosystems was studied. The concentration of major elements viz. Ca, Mg, K, Ti and trace metals viz. Cr, Mn, Co, Al, Fe, Ni, Cu, Zn, Cd and Pb were analysed by energy dispersive X-ray fluorescence technique. Contamination factor, geo-accumulation index, probable effect level, enrichment factor and pollution load index were calculated to evaluate the pollution status. Except cadmium, CF values for all the metals ranged between 1≤CF≤3 indicating moderate metal contaminations along the coast. Mean PEL quotient (Qm-PEL) indicated toxicity probability to be below 21%. Fe, Cu, Zn and Co showed significant positive correlation (p<0.01) with clay. Chromium was the only metal that demonstrated strong negative correlation with clay (p<0.01) and positive correlation (p<0.01) with sand content.
Показать больше [+] Меньше [-]Effects of short-term weathering on the stable carbon isotope compositions of crude oils and fuel oils Полный текст
2017
Liu, Yu | Xu, Jixiang | Chen, Wenjing | Li, Ying
A short-term simulated weathering experiment was performed on two crude oils and two heavy fuel oils under natural conditions to evaluate the effects of natural weathering processes by using gas chromatography–mass spectrometry combined with gas chromatography–isotopic ratio mass spectrometry. The results of diagnostic ratios of n-alkanes show that only odd to even predominance (OEP1, OPE2) and carbon preference index (CPI) remain stabilized during the 28 d weathering process, but they cannot effectively distinguish the four types of oils. Statistical analyses based on paired sample t-test and principal component analysis (PCA) revealed that stable carbon isotope compositions of n-alkanes in the four studied oils have no significant changes over the weathering time, and that the carbon isotope discrimination (Δδ13C) of n-alkanes is <3‰. We have provided evidence that the stable carbon isotope compositions of n-alkanes compared to n-alkanes diagnostic ratios significantly improve the efficiency and fidelity of the oil fingerprint identification.
Показать больше [+] Меньше [-]Performance of the dominant bacterial species and microbial community in autotrophic denitrification coupled with iron cycle in immobilized systems Полный текст
2017
Su, Jun feng | Cheng, Ce | Huang, Tinglin | Wei, Li
We used three stable reactors to investigate the rates of nitrate removal coupled with iron cycle and the subsequent influence of the reaction on bacterial communities. The iron-reducing bacterium Klebsiella sp. FC61 was immobilized on the reactor columns of the experimental groups B (only Klebsiella) and C (Klebsiella+magnetite). With the fluctuation of Fe2+ to Fe3+ (iron cycle), the average nitrate removal efficiency increased from 73.22% to 93.91% and 86.92% to 97.84% in groups B and C, respectively, as the influent nitrate concentration decreased from 40 to 10mg/L. However, the average rate of nitrate removal showed the opposite trend (from 2.08mg/L/h to 0.67mg/L/h and 2.41mg/L/h to 0.69mg/L/h in groups B and C, respectively) as the influent nitrate concentration decreased. Analysis of microbial distribution and community structures indicated that the population of Klebsiella sp. increased in groups B (from 18.21% to 41.21%) and C (from 25.43% to 46.80%) and contributed to the effective removal of nitrate in the reactors.
Показать больше [+] Меньше [-]Oxidative stress and genotoxicity biomarker responses in tilapia (Oreochromis niloticus) exposed to environmental concentration of 1-nitropyrene Полный текст
2017
Bacolod, Eugene T. | Uno, Seiichi | Villamor, Shiela S. | Koyama, Jiro
The present study aimed to assess whether environmental 1-nitropyrene (1-NP) concentration will induce genotoxicity and oxidative damages in tilapia, lives in estuarine and brackish water. Tilapia were exposed to waterborne 1-NP. Cellular antioxidant enzyme activity of glutathione peroxidase and oxidative damage, i.e., lipid peroxidation, protein and DNA oxidation were used as biomarkers of oxidative stress, while the micronucleus test was used for evaluation of chromosomal damage and was used as an indication of genotoxicity. Results showed that all biomarkers for oxidative stress positively responded, and micronucleus and other nuclear abnormalities frequencies significantly increased (p<0.001). This study showed that environmentally relevant 1-NP concentration in test water (0.15ng/L) and in fish (3ng/kg) induced genotoxicity and oxidative stress. Micronuclei and other nuclear abnormalities were probably formed as a result of oxidative stress. In conclusion, exposure to lower waterborne 1-NP concentration can pose a risk to freshwater and estuarine organisms through accumulation.
Показать больше [+] Меньше [-]Fate of microplastics and mesoplastics carried by surface currents and wind waves: A numerical model approach in the Sea of Japan Полный текст
2017
Iwasaki, Shinsuke | Isobe, Atsuhiko | Kako, Shin'ichiro | Uchida, Keiichi | Tokai, Tadashi
A numerical model was established to reproduce the oceanic transport processes of microplastics and mesoplastics in the Sea of Japan. A particle tracking model, where surface ocean currents were given by a combination of a reanalysis ocean current product and Stokes drift computed separately by a wave model, simulated particle movement. The model results corresponded with the field survey. Modeled results indicated the micro- and mesoplastics are moved northeastward by the Tsushima Current. Subsequently, Stokes drift selectively moves mesoplastics during winter toward the Japanese coast, resulting in increased contributions of mesoplastics south of 39°N. Additionally, Stokes drift also transports micro- and mesoplastics out to the sea area south of the subpolar front where the northeastward Tsushima Current carries them into the open ocean via the Tsugaru and Soya straits. Average transit time of modeled particles in the Sea of Japan is drastically reduced when including Stokes drift in the model.
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