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Resultados 1751-1760 de 5,098
Historical trends of perfluoroalkyl substances (PFASs) in dated sediments from semi-enclosed bays of Korea
2018
Shen, Aihua | Lee, Sunggyu | Ra, Kongtae | Suk, Dongwoo | Moon, Hyo-Bang
Information is scarce on historical trends of perfluoroalkyl substances (PFASs) in the coastal environment. In this study, four sediment cores were collected from semi-enclosed bays of Korea to investigate the pollution history, contamination profiles, and environmental burden of PFASs. The total PFAS concentrations in sediment cores ranged from 6.61 to 821 pg/g dry weight. The highest concentrations of PFASs were found in surface or sub-surface sediments, indicating on-going contamination by PFASs. Historical trends in PFASs showed a clear increase since the 1980s, which was consistent with the global PFAS consumption pattern. Concentrations of PFASs were dependent on the organic carbon content in sediment cores. PFOS and longer-chain PFASs were predominant in all of the sediment cores. In particular, a large proportion of longer-chain PFASs was observed in the upper layers of the sediment cores from industrialized coastal regions. Inventories and fluxes estimated for PFASs were similar to those for PCDD/Fs.
Mostrar más [+] Menos [-]Underwater noise from airplanes: An overlooked source of ocean noise
2018
Erbe, Christine | Williams, Rob | Parsons, Miles | Parsons, Sylvia K. | Hendrawan, I Gede | Dewantama, I Made Iwan
The effects of underwater noise pollution on marine life are of increasing concern. Research and management have focussed on the strongest underwater sound sources. Aerial sound sources have understandably been ignored as sound transmits poorly across the air-water interface. However, there might be situations when air-borne noise cannot be dismissed. Commercial passenger airplanes were recorded in a coastal underwater soundscape exhibiting broadband received levels of 84–132 dB re 1 μPa rms. Power spectral density levels of airplane noise underwater exceeded ambient levels between 12 Hz and 2 or 10 kHz (depending on site) by up to 36 dB. Underwater noise from airplanes is expected to be audible to a variety of marine fauna, including seals, manatees, and dolphins. With many of the world's airports lying close to the coast, it is cautioned that airplane noise not be ignored, in particular in the case of at-risk species in small, confined habitats.
Mostrar más [+] Menos [-]Marine litter on the seafloor of the southern Baltic
2018
Urban-Malinga, Barbara | Wodzinowski, Tycjan | Witalis, Bartosz | Zalewski, Mariusz | Radtke, Krzysztof | Grygiel, Włodzimierz
Marine litter occurrence and composition were investigated during routine bottom trawl fish surveys type BITS performed in the Polish Maritime Areas (the southern Baltic Sea). Sampling covered a distance of 325km and an area of 16km² at a depth range of 19–110m. Litter densities varying between 0 items/ha (34% of tows) and 2.23items/ha with a mean of 0.20items/ha (SD=0.30) are at the bottom range of densities reported from other shelf habitats worldwide at similar water depths. The majority of the items (40%) were found at a depth range of 51–60m. Overall, plastic was the most common litter type (67% of all items) found in all tows with litter. The results of this study indicate that despite the Baltic being a semi-enclosed basin, with a densely populated coastline and extensive shipping, marine litter pollution of the southern Baltic seafloor is low compared to other coastal areas.
Mostrar más [+] Menos [-]T lymphocyte-proliferative responses of harbor seal (Phoca vitulina) peripheral blood mononuclear cells (PBMCs) exposed to pharmaceuticals in vitro
2018
Kleinert, Christine | Lacaze, Emilie | Fortier, Marlène | Hammill, Mike | De Guise, Sylvain | Fournier, Michel
The ubiquity of pharmaceuticals in the aquatic environment and the accumulation in organisms of lower trophic levels have been documented. The immunotoxicity of these xenobiotics has however been little investigated. This study assessed the effects of pharmaceuticals on the immune responses of harbor seal lymphocytes. Peripheral blood mononuclear cells isolated from harbor seal pups were exposed to varying concentrations of 17α-ethinyl estradiol (250–50,000μg/L), naproxen (500–100,000μg/L), carbamazepine (500–100,000μg/L), erythromycin (750–150,000μg/L) and binary mixtures thereof in vitro. All individual compounds and mixtures inhibited lymphocyte proliferation. Mixture effects were non-additive and predictive values overestimated the inhibition of proliferation. Male pups were more sensitive to erythromycin exposure. Comparison with the sensitivity of the 11B7501 cell line showed a higher sensitivity of pups to individual compounds and the inverse trend for mixtures. Based on our results, we hypothesize that pharmaceuticals may have the potential to interrupt immune functions in harbor seals.
Mostrar más [+] Menos [-]Feeding ecology and ingestion of plastic fragments by Priacanthus arenatus: What's the fisheries contribution to the problem?
2018
Cardozo, Ana L.P. | Farias, Eduardo G.G. | Rodrigues-Filho, Jorge L. | Moteiro, Isabel B. | Scandolo, Tatianny M. | Dantas, David V.
Atlantic Bigeye (Priacanthus arenatus) is a demersal species from the Priacanthidae family with little literature relating to its biology and catch aspects. Due to this lack of research, the focus of this effort was to describe the feeding preferences of Atlantic Bigeye and to evaluate the influence of plastic debris derived from the local fisheries activities on its diet. The most important items were Corophiidae, Penaeidae, Actinopterygii, Isopoda, Cephalopoda, Policheta and plastic. Plastic was present in 49.17% of the stomachs analyzed. A total of 210 plastic fragments were found, and 63% were derived from fishing. Of those, 55% were derived from paint fragments from vessels and 8% from synthetic fibers (PA). The results suggest that plastic fragments found in stomachs are related to the species' natural diet and that this debris is locally deposited in the coastal environment. Fishing resources appear to have been affected by this local marine pollution.
Mostrar más [+] Menos [-]Spatio-temporal variation of anthropogenic marine debris on Chilean beaches
2018
Hidalgo-Ruz, Valeria | Honorato-Zimmer, Daniela | Gatta-Rosemary, Magdalena | Núñez Tomás, Paloma | Hinojosa, Iván A. | Thiel, Martin
We examined the hypothesis that in an emerging economy such as Chile the abundances of Anthropogenic Marine Debris (AMD) on beaches are increasing over time. The citizen science program Científicos de la Basura (“Litter Scientists”) conducted three national surveys (2008, 2012 and 2016) to determine AMD composition, abundance, spatial patterns and temporal trends. AMD was found on all beaches along the entire Chilean coast. Highest percentages of AMD in all surveys were plastics and cigarette butts, which can be attributed to local sources (i.e. beach users). The Antofagasta region in northern Chile had the highest abundance of AMD compared with all other zones. Higher abundances of AMD were found at the upper stations from almost all zones. No significant tendency of increasing or decreasing AMD densities was observed during the 8years covered by our study, which suggests that economic development alone cannot explain temporal trends in AMD densities.
Mostrar más [+] Menos [-]Identifying bioindicators across trait-taxon space for assessing water quality in marine environments
2018
The response units of protozoan communities, based on a community-weighted mean (CWM) dataset across trait-taxon space, were investigated in order to determine their utility as bioindicators of marine water quality. From a total of 17 functional categories of seven biological traits, three functional response units (FRUs) were identified at correlation levels of >0.75. FRUs 1 and 3 generally dominated the communities in more polluted areas during warm seasons, while FRU2 appeared to prefer less polluted waters and dominated the communities in spring and winter. Correlation analysis demonstrated that the CWM values of FRUs 1 and 3 were significantly positively correlated to the concentrations of chemical oxygen demand (COD), whereas those of FRU2 were negatively correlated to COD. Across taxon-function space, 16 species were identified as potential bioindicators of water quality. These results suggest that redundancy analysis across trait-taxon space is a useful tool for identifying indicators of environmental quality.
Mostrar más [+] Menos [-]Mangrove vegetation enhances soil carbon storage primarily through in situ inputs rather than increasing allochthonous sediments
2018
Xiong, Yanmei | Liao, Baowen | Wang, Faming
The role of soil carbon (C) in coastal wetlands as a net sink is related to the relative abundance of autochthonous versus allochthonous C. We aimed to investigate soil C sources and the pathways by which mangrove vegetation enhances soil C accumulation. We sampled soil to 1 m depth in seven oceanic mangrove forests and an adjacent un-vegetated mudflat at Dongzhai Bay, China. Stable C isotope technique was used to separate autochthonous and allochthonous C sources. Autochthonous C accounted for 27–97% of soil C stock in the top meter. Soil C density was 1.1–3.6 times higher in mangroves than in the mudflat. Among the increased soil C in mangroves relative to mudflat, autochthonous C accounted for 65–100% of the increments. The results suggest that mangrove vegetation enhances soil C storage primarily through in situ inputs, therefore the substantial soil C stocks commonly found in mangroves play an important role in sequestering atmospheric CO2.
Mostrar más [+] Menos [-]Phylogenetic characterization of culturable bacteria and fungi associated with tarballs from Betul beach, Goa, India
2018
Tarballs are semisolid blobs of crude oil, normally formed due to weathering of crude-oil in the sea after any kind of oil spills. Microorganisms are believed to thrive on hydrocarbon-rich tarballs and possibly assist in biodegradation. The taxonomy of ecologically and economically important tarball-associated microbes, however, needs improvement as DNA-based identification and phylogenetic characterization have been scarcely incorporated into it. In this study, bacteria and fungi associated with tarballs from touristic Betul beach in Goa, India were isolated, followed by phylogenetic analyses of 16S rRNA gene and the ITS sequence-data to decipher their clustering patterns with closely-related taxa. The gene-sequence analyses identified phylogenetically diverse 20 bacterial genera belonging to the phyla Proteobacteria (14), Actinobacteria (3), Firmicutes (2) and Bacteroidetes (1), and 8 fungal genera belonging to the classes Eurotiomycetes (6), Sordariomycetes (1) and Leotiomycetes (1) associated with the Betul tarball samples. Future studies employing a polyphasic approach, including multigene sequence-data, are needed for species-level identification of culturable tarball-associated microbes. This paper also discusses potentials of tarball-associated microbes to degrade hydrocarbons.
Mostrar más [+] Menos [-]Development of a storm surge driven water quality model to simulate spills during hurricanes
2018
Kiaghadi, Amin | Rifai, H. S. | Burleson, Daniel W.
Hurricanes can cause widespread environmental pollution that has yet to be fully articulated. This study develops a predictive water quality model to forecast potential contamination resulting from buckled or ruptured storage tanks in coastal industrialized areas when subjected to storm surge. The developed EFDC-Storm Surge model (EFDC-SS) couples EPA's EFDC code with the SWAN-ADCIRC hurricane simulation model. EFDC-SS is demonstrated using the Houston Ship Channel in Texas as a testbed and hurricane Ike as a model hurricane. Conservative and decaying dye runs evaluated various hurricane scenarios, combined with spills released at different locations and release times. Results showed that tank locations with shorter distances to the main waterbody and lower ground elevations have a higher risk of inundation and rapid spill mass transport. It was also determined that hurricane strength and landfall location, the location of the spill, and the spill release time relative to peak surge were interdependent.
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