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The eutrophication commandments
2012
Fulweiler, R.W. | Rabalais, N.N. | Heiskanen, A.S.
Typically, rising atmospheric carbon dioxide concentrations are used to illustrate how humans have impacted the earth. However, we have also dramatically altered the amount of nitrogen (N) and phosphorus (P) cycling through the biosphere. Eventually these nutrients are carried to coastal receiving waters where they cause severe, often negative consequences including increased phytoplankton and macroalgae blooms, loss of submerged aquatic vegetation, low oxygen events, and decreased biodiversity. In many systems mitigation efforts are now underway to return these ecosystems to a less impacted state. While many uncertainties about the best way to manage eutrophic systems remain it is clear that we must take action to lessen our human nutrient footprint. Based on our current understanding of eutrophic systems we present ten eutrophication commandments or guidelines as a tool for scientists, policy makers, managers, and the public.
Показать больше [+] Меньше [-]Effect of zinc sacrificial anode degradation on the defence system of the Pacific oyster, Crassostrea gigas: Chronic and acute exposures
2012
Mottin, Elmina | Caplat, Christelle | Latire, Thomas | Mottier, Antoine | Mahaut, Marie-Laure | Costil, Katherine | Barillier, Daniel | Lebel, Jean-Marc | Serpentini, Antoine
Two types of exposures were performed to assess the effects of zinc released from sacrificial anode degradation: a chronic exposure, in which oysters were exposed to 0.53±0.04mgZnL⁻¹ for 10weeks, and an acute exposure, where oysters were exposed to 10.2±1.2mgZnL⁻¹ for 1week. At the end of the acute exposure experiment, 81.8% mortality was recorded. In contrast, no mortality was detected after 10weeks exposure. Moreover, all of the immune system biomarkers studied, except the number of circulating haemocytes, were stimulated by a moderate level of zinc and inhibited by a high level. Our exposure conditions did not induce SOD or MXR mRNA expression in gills and digestive gland. However, an increase of MT mRNA is observed in these tissues. The results indicate that oysters are sensitive to acute zinc toxicity but are only moderately affected by a mild zinc concentration.
Показать больше [+] Меньше [-]Testing benthic foraminiferal distributions as a contemporary quantitative approach to biomonitoring estuarine heavy metal pollution
2012
Foster, William J. | Armynot du Châtelet, Eric | Rogerson, M. (Mike)
Biomonitoring of estuarine pollution is the subject of active research, and benthic foraminifera are an attractive group to use for these purposes due to their ubiquitous presence in saline water and wide diversity. Here, we describe a case study of biomonitoring using benthic foraminifera in the French Mediterranean lagoon, Bages-Sigean lagoon. In this case, the major pollutants of interest are heavy metals in the sediment, particularly contaminated by Cu and Cd derived from industrial and agricultural sources. The foraminiferal assemblages of the Bages-Sigean lagoon are typical of normal paralic environments, but unusually almost completely lack agglutinated forms. The density of benthic foraminifera was shown to be more influenced by the sediment characteristics rather than heavy metal pollution. However, the relative abundance of Quinqueloculina bicostata was shown to increase in the most polluted areas and we propose that this taxon may be used as an indicator of heavy metal pollution.
Показать больше [+] Меньше [-]Heavy metal pollution in sediments of a typical mariculture zone in South China
2012
Zhang, Wenfeng | Liu, Xueping | Cheng, Hefa | Zeng, E. Y. (Eddy Y.) | Hu, Yuanan
The heavy metal inventory and the ecological risk of the estuarine sediments in Hailing Bay, an important maricultural zone along the southern coast of China, were investigated. Results show that the surface sediments were mainly polluted by As (2.17–20.34mg/kg), Ni (1.37–42.50mg/kg), Cu (1.21–58.84mg/kg) and Zn (11.69–219.22mg/kg). Furthermore, the aquafarming zone was significantly more polluted than the non-aquafarming zone, and cluster analysis suggested additional sources of heavy metal input in the aquafarming zone. As, Cr, Cu, Ni, Pb and Zn were mainly present in the non-bioavailable residual form in the surface sediments, whereas Cd was predominantly in the highly mobile acid soluble and reducible fractions. The ecological risk of the polluted sediments stemmed mainly from Cd, and from As, Cu and Pb to less degrees. The highest potential risks occurred near the aquaculture base, indicating the need to control heavy metal inputs from aquafarming activities.
Показать больше [+] Меньше [-]Determination of deployment specific chemical uptake rates for SPMD and PDMS using a passive flow monitor
2012
O’Brien, Dominique | Komarova, Tatiana | Mueller, Jochen F.
Passive sampling techniques facilitate the time-integrated measurement of pollutant concentrations through the use of a selective receiving phase. Accurate quantification using passive sampling devices rely on the implementation of methods that will negate the effects of environmental factors (flow, temperature, etc.) or that will allow the calculation of the chemical specific rates of uptake (Rₛ) into the passive sampler employed. We have applied an in situ calibration technique based on the dissolution of gypsum to measure the average water velocity to which a sampler has been exposed. We demonstrate that the loss of gypsum from the passive flow monitor (PFM) can be applied to predict changes in Rₛ dependent on flow when using the absorbent SPMD (semipermeable membrane device) and PDMS (polydimethyl siloxan) passive samplers. The application of the PFM will enhance the accuracy of measurements made when calculating and reporting environmental pollutant concentrations using a passive sampling device.
Показать больше [+] Меньше [-]Molecularly imprinted polymer for selective extraction of malachite green from seawater and seafood coupled with high-performance liquid chromatographic determination
2012
Lian, Ziru | Wang, Jiangtao
In this paper, a highly selective sample cleanup procedure combining molecular imprinting technique (MIT) and solid-phase extraction (SPE) was developed for the isolation of malachite green in seawater and seafood samples. The molecularly imprinted polymer (MIP) was prepared using malachite green as the template molecule, methacrylic acid as the functional monomer and ethylene glycol dimethacrylate as the cross-linking monomer. The imprinted polymer and non-imprinted polymer were characterized by scanning electron microscope and static adsorption experiments. The MIP showed a high adsorption capacity and was used as selective sorbent for the SPE of malachite green. An off-line molecularly imprinted solid-phase extraction (MISPE) method followed by high-performance liquid chromatography with diodearray detection for the analysis of malachite green in seawater and seafood samples was also established. Finally, five samples were determined. The results showed that malachite green concentration in one seawater sample was at 1.30μgL⁻¹ and the RSD (n=3) was 4.15%.
Показать больше [+] Меньше [-]Occurrence and partitioning of endocrine-disrupting compounds in the marine environment of Thermaikos Gulf, Northern Aegean Sea, Greece
2012
Arditsoglou, Anastasia | Voutsa, Dimitra
An integrated study was conducted to determine the presence of phenolic and steroid endocrine-disrupting compounds (EDCs), in the marine environment of Thermaikos Gulf, Northern Aegean Sea, Greece. Seawater, suspended particulate matter, sediments and biota were examined for nonylphenol, octylphenol, their mono- and diethoxylate oligomers, bisphenol A, estrone, 17α-estradiol, 17β-estradiol, estriol, mestranol and 17 α -ethynylestradiol. Phenolic compounds were detected in all of the compartments, with nonylphenol and its ethoxylates being the dominant pollutants. The occurrence of nonylphenol in sediments presents a significant risk to the biota. Mussels exhibited relatively low concentrations and low bioconcentration factors for NP and OP. The effect of terrestrial sources of the EDCs on the marine environment is discussed. The influence of suspended particulate matter and organic carbon in the partition of the EDCs between the dissolved and the particulate phase was investigated.
Показать больше [+] Меньше [-]Monitoring strategies for drill cutting discharge in the vicinity of cold-water coral ecosystems
2012
Purser, Autun | Thomsen, Laurenz
Cold-water coral reefs represent some of the most biodiverse and biomass rich ecosystems in the marine environment. Despite this, ecosystem functioning is still poorly understood and the susceptibility of key species to anthropogenic activities and pollutants is unknown. In European waters, cold-water corals are often found in greatest abundance on the continental margin, often in regions rich in hydrocarbon reserves. In this viewpoint paper we discuss some of the current strategies employed in predicting and minimizing exposure of cold-water coral reef ecosystems on the Norwegian margin to waste materials produced during offshore drilling operations by the oil and gas industry. In the light of recent in situ and experimental research conducted with the key reef species Lophelia pertusa, we present some possible improvements to these strategies which may be utilized by industry and managers to further reduce the likelihood of exposure. We further highlight important outstanding research questions in this field.
Показать больше [+] Меньше [-]Deep-sea foraminifera from the Cassidaigne Canyon (NW Mediterranean): Assessing the environmental impact of bauxite red mud disposal
2012
Fontanier, C. | Fabri, M.-C. | Buscail, R. | Biscara, L. | Koho, K. | Reichart, G.J. | Cossa, D. | Galaup, S. | Chabaud, G. | Pigot, L.
Benthic foraminiferal assemblages were investigated from two sites along the axis of the Cassidaigne Canyon (NW Mediterranean Sea). Both areas are contaminated by bauxite red mud enriched in iron, titanium, vanadium and chromium. These elemental enrichments are related to bauxite-derived minerals and various amorphous phases. At the shallowest station located very close to the pipe outlet, the benthic living foraminiferal community is characterised by a very low diversity and by an unusual dominance of Gyroidina umbonata and Bulimina marginata. The mechanical stress related to downslope transport of red mud is a likely source of hydro-sedimentary pollution precluding the settlement of diverse fauna. The living and dead foraminiferal faunas from the deepest site are typical of oligo-mesotrophic conditions prevailing in natural environments. There, bauxite residues have obviously no environmental impact on foraminiferal faunas. The bioavailability of trace metals is likely low as elemental enrichments were not observed in foraminiferal test chemistry.
Показать больше [+] Меньше [-]Effect of bioemulsificant exopolysaccharide (EPS₂₀₀₃) on microbial community dynamics during assays of oil spill bioremediation: A microcosm study
2012
Cappello, Simone | Genovese, Maria | Della Torre, Camilla | Crisari, Antonella | Hassanshahian, Mehdi | Santisi, Santina | Calogero, Rosario | Yakimov, Michail M.
Microcosms experiments were carried out to evaluate the effect of bioemulsificant exopolysaccharide (EPS₂₀₀₃) on microbial community dynamics. An experimental seawater microcosm, supplemented with crude oil and EPS₂₀₀₃ (SW+OIL+EPS₂₀₀₃), was monitored for 15days and compared to control microcosm (only oil-polluted seawater, SW+OIL). Determination of bacterial abundance, heterotrophic cultivable and hydrocarbon-degrading bacteria were carried out during all experimentation period. The microbial community dynamic was monitored by isolation of total RNA, RT-PCR amplification of 16S rRNA, cloning and sequencing. Oil degradation was monitored by GC–MS analysis. Bioemulsificant addition stimulated an increase of the total bacterial abundance, change in the community structure and activity. The bioemulsificant also increased of 5 times the oil biodegradation rate. The data obtained from microcosm experiment indicated that EPS₂₀₀₃ could be used for the dispersion of oil slicks and could stimulate the selection of marine hydrocarbon degraders thus increasing bioremediation process.
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