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Fractionation, sources and budgets of potential harmful elements in surface sediments of the East China Sea Texto completo
2013
Yu, Yu | Song, Jinming | Li, Xuegang | Yuan, Huamao | Li, Ning
Total concentrations, chemical fractions by BCR procedure and enrichment factors of nine potential harmful elements (V, Cr, Co, Ni, Cu, Zn, Mo, Cd and Pb) in surface sediments of the East China Sea (ECS) were investigated. Spatial distributions illustrated that PHEs (potential harmful elements) were mainly from the Changjiang River and the Jiangsu coastal current, except Pb which was influenced by atmospheric input. Sediments in the ECS were moderately polluted with Cd, Pb, Zn and Cu according to their enrichment factors (EFs). Distributions of EFs and labile fractions revealed that anthropogenic Cd and Cu were mainly input though the Changjiang, Pb pollutant was delivered from the Changjiang and atmosphere, while Zn was impacted by terrestrial pollution from the Changjiang and the Hangzhou Bay. Budget calculation showed that the Changjiang contributed 82–90% of PHE influxes. Thirty-eight to 77% of PHEs were buried in sediment, mainly along the inner shelf.
Mostrar más [+] Menos [-]Harboring oil-degrading bacteria: A potential mechanism of adaptation and survival in corals inhabiting oil-contaminated reefs Texto completo
2013
Al-Dahash, Lulwa M. | Mahmoud, Huda M.
Certain coral reef systems north of the Arabian Gulf are characterized by corals with a unique ability to thrive and flourish despite the presence of crude oil continuously seeping from natural cracks in the seabed. Harboring oil-degrading bacteria as a part of the holobiont has been investigated as a potential mechanism of adaptation and survival for corals in such systems. The use of conventional and molecular techniques verified a predominance of bacteria affiliated with Gammaproteobacteria, Actinobacteria and Firmicutes in the mucus and tissues of Acropora clathrata and Porites compressa. These bacteria were capable of degrading a wide range of aliphatic (C9–C28) aromatic hydrocarbons (Phenanthrene, Biphenyl, Naphthalene) and crude oil. In addition, microcosms supplied with coral samples and various concentrations of crude oil shifted their bacterial population toward the more advantageous types of oil degraders as oil concentrations increased.
Mostrar más [+] Menos [-]Effect of extraction-method, period of incubation and tidal emersion on the viability of haemocytes from oysters Texto completo
2013
Moreira, Fabiana T. | Browne, Mark Anthony | Coleman, Ross A.
The impacts of pollution on marine organisms are often investigated using the viability of their haemocytes. Although this assay is routinely used in monitoring, field and laboratory experimentation, there has been less effort in further optimizing procedures to reduce artefacts and facilitate sampling over large geographic areas.Using the oyster Saccostrea glomerata as a model species, we investigated the effects of different techniques for extracting haemolymph, period of incubation with dye and emersion-time (e.g. tidal-state) on the viability of haemocytes. Collecting haemocytes with a syringe, through a drilled hole in the shell, increased the viability of haemocytes by almost 50%. While emersion-time and incubating haemocytes with the dye for up to 4h did not affect viability.This simple in situ approach provides a less destructive method for extracting haemocytes, allowing their viability to be measured as part of large-scale experiments without jeopardizing the surrounding assemblage of animals and plants.
Mostrar más [+] Menos [-]Direct measurement of dissolved N2 and denitrification along a subtropical river-estuary gradient, China Texto completo
2013
Wu, Jiezhong | Chen, Nengwang | Hong, Huasheng | Lu, Ting | Wang, Longjian | Chen, Zhuhong
The spatial pattern and seasonal variation of denitrification were investigated during 2010–2011 in the Jiulong River Estuary (JRE) in southeast China. Dissolved N2 was directly measured by changes in the N2:Ar ratio. The results showed that excess dissolved N2 ranged from −9.9 to 76.4μmolL−1. Tidal mixing leads to a seaward decline of dissolved gaseous concentrations and water–air fluxes along the river-estuary gradient. Denitrification at freshwater sites varied between seasons, associated with changes in N input and water temperature. The denitrification process was controlled by the nitrate level at freshwater sites, and the excess dissolved N2 observed at the tidal zone largely originated from upstream water transport. Compared to other estuaries, JRE has a relative low gaseous removal efficiency (Ed=12% of [DIN]; annual N removal=24% of DIN load), a fact ascribed to strong tidal mixing, coarse-textured sediment with shallow depth before bedrock and high riverine DIN input.
Mostrar más [+] Menos [-]Development and validation of a method for the simultaneous extraction and separate measurement of oxytetracycline, florfenicol, oxolinic acid and flumequine from marine sediments Texto completo
2013
Norambuena, Luis | Gras, Nuri | Contreras, Sergio
A simple and rapid method for the detection and extraction of oxolinic acid, flumequine, florfenicol and oxytetracycline from marine sediments was developed and validated. The analytes were extracted from the marine sediment using a solution of oxalic acid diluted in methanol with sonication before detection by HPLC using a diode-array detector (florfenicol and oxytetracycline) and fluorescence (oxolinic acid and flumequine). The quantification limits (QL) were 100ng/g for oxytetracycline and florfenicol and 5ng/g for oxolinic acid and flumequine. The coefficients of variation of the repeatability and intermediate precision were less than 10% in all of the analytes. The calibration curves were linear between 50 and 500ng/ml for oxytetracycline and florfenicol and 1 and 20ng/ml for oxolinic acid and flumequine. The recuperation rate for the analytes was above 86%.
Mostrar más [+] Menos [-]Cumulative impacts on seabed habitats: An indicator for assessments of good environmental status Texto completo
2013
Korpinen, Samuli | Meidinger, Manuel | Laamanen, Maria
The European seas are under anthropogenic pressures impacting the state of water quality, benthic habitats and species. The EU Marine Strategy Framework Directive (MSFD) requires the Member States to assess the impacts of pressures and make a programme of measures leading to good environmental status (GES) by 2020. This study presents a method for assessing the quantity and distribution of anthropogenic impacts on benthic habitats in the Baltic Sea by using spatial data of human pressures and benthic habitats. The southern sub-basins were more extensively impacted than the northern sub-basins. Over the entire sea area, deep sea habitats were more impacted than shallower infralittoral and circalittoral habitats. Sand and coarse sediments were the seabed types relatively most impacted in the Baltic Sea scale. A comparison against tentative thresholds for GES showed that in the sub-basin scale only one third of the habitat types was in GES.
Mostrar más [+] Menos [-]Biogeochemical characterization of MC252 oil:sand aggregates on a coastal headland beach Texto completo
2013
Urbano, Marilany | Elango, Vijaikrishnah | Pardue, John H.
MC252 oil:sand aggregates, termed surface residue balls (SRBs), were sampled for physical, chemical and microbial characteristics from different tidal zones on a coastal headland beach in Louisiana, USA. Supratidal SRBs were smaller, had low moisture content, and salinities that were <2ppt. Intertidal SRBs were hypersaline and had higher N and sulfate concentrations, consistent with regular tidal inundation. Crude oil components were highest in the intertidal “oil mat” SRBs with C1- and C2-phenanthrenes, C2- and C3-dibenzothiophenes comprising the majority of the PAH concentrations. In the other SRB categories, PAHs and alkanes were depleted and profiles were skewed toward higher molecular weight compounds. Oxygen microelectrode measurements demonstrated that saturated O2 is present immediately after wetting, but O2 consumption in the interior of the aggregate occurs after a few days. Microbial populations varied with position on the beach but sequences similar to known PAH-degrading taxa (Mycobacterium sp. and Stenotrophomonas sp.) were observed.
Mostrar más [+] Menos [-]Distribution and geochemical speciation of heavy metals in sediments from coastal area suffered rapid urbanization, a case study of Shantou Bay, China Texto completo
2013
Qiao, Yongmin | Yang, Yang | Gu, Jiguang | Zhao, Jiangang
Eight metals in sediment samples at 15 sites from the Shantou Bay were analyzed with BCR sequential extraction protocol to obtain the metal distribution patterns in the bay. The results showed that the heavy metal pollutions in upper bay were more severe than in middle and down reaches of the bay. Both total and non-residual fractions of metals with a exception of Mn showed a seaward decrease trend. More than 54% of the total concentrations of Cd, Mn and Zn existed in the acid soluble fraction. Ni, Co, Cr and Fe mainly (more than 51%) occurred in the residual fraction. While Pb and Cu dominantly presented in the reducible (50%) and oxidable (33%) fraction respectively. Principal component analysis (PCA) revealed that the heavy metals in the non-residual fractions resulted from largely anthropogenic sources, including river input, city runoff and port discharge. These contributing sources are highlighted by cluster analysis.
Mostrar más [+] Menos [-]Antifouling biocides in water and sediments from California marinas Texto completo
2013
Sapozhnikova, Yelena | Wirth, Edward | Schiff, Kenneth | Fulton, Michael
Irgarol 1051 is a common antifouling biocide and is highly toxic to non-target plant species at low ng/L concentrations. We measured up to 254ng/L Irgarol in water and up to 9ng/g dry weight Irgarol in sediments from Southern California recreational marinas. Irgarol’s metabolite, M1, concentrations were up to 62ng/L in water and 5ng/g dry weight in sediments. Another antifouling biocide, diuron, reached up to 68ng/L in water and 4ng/g dry weight in sediments. The maximum Irgarol concentrations in water were greater than the Irgarol concentration recommended as the plant toxicity benchmark (136ng/L), suggesting that Irgarol concentrations may be high enough to cause changes in phytoplankton communities in the sampled marinas. Irgarol concentrations measured in sediments were greater than calculated Environmental Risk Limits (ERLs) for Irgarol in sediments (1.4ng/g). Antifouling pesticide accumulation in sediments may present a potential undetermined risk for benthic organisms.
Mostrar más [+] Menos [-]Presence of plastic debris in loggerhead turtle stranded along the Tuscany coasts of the Pelagos Sanctuary for Mediterranean Marine Mammals (Italy) Texto completo
2013
This work evaluated the presence and the frequency of occurrence of marine litter in the gastrointestinal tract of 31 Caretta caretta found stranded or accidentally bycaught in the North Tyrrhenian Sea. Marine debris were present in 71% of specimens and were subdivided in different categories according to Fulmar Protocol (OSPAR 2008). The main type of marine debris found was user plastic, with the main occurrence of sheetlike user plastic. The small juveniles showed a mean±SD of marine debris items of 19.00±23.84, while the adult specimens showed higher values of marine litter if compared with the juveniles (26.87±35.85). The occurrence of marine debris observed in this work confirms the high impact of marine debris in the Mediterranean Sea in respect to other seas and oceans, and highlights the importance of Caretta caretta as good indicator for marine litter in the Marine Strategy Framework Directive (MSFD) of European Union.
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