Results 1 - 10 of 1905
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[en] Highlights: • Microorganisms are believed to thrive on hydrocarbon-rich tarballs and possibly assist in biodegradation of tarballs • Phylogenetic characterization has been scarcely incorporated into the taxonomy of tarball-associated microbes • In this study, tarball-associated bacteria and fungi from touristic Betul beach, Goa, India were characterized • 28 microbial genera (20 bacterial genera and 8 fungal genera) were identified based on gene sequence analyses. - Abstract: 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.
[en] Highlights: • A mixture of 4 plastics was submerged in seawater for 12 months. The chlorine content and the NCV were periodically measured. • Thermal properties of these plastics were affected by the contact with the marine water. PET was the most affected polymer. • Pyrolysis and combustion runs were carried out. Emission of gases, PAHs, ClBzs, ClPhs, BrPhs, PCBs and PCDD/Fs were studied. • Pollutant emissions are higher when the content of oxygen in the process is lower. • Emissions of chlorinated species are not affected by the chlorine content. The production of PCBs and PCDD/Fs was very low. - Abstract: A mixture of polyethylene (PE), polyethylene-terephtalate (PET), polypropylene (PP) and Nylon was submerged in marine water during 12 moths. The chlorine content of these plastics was measured through the passing time. Thermobalance was used to look for differences in the thermal decomposition of the plastics during in that time interval. Degradation of PET, PP and Nylon produced changes in the weight loss curve, but behaviour of PE is confusing. Pyrolysis and combustion at 850 °C was finally performed to get knowledge of the possible differences in the emission of main gases, volatiles and semivolatiles including polycyclic aromatic hydrocarbons (PAHs), polychlorinated benzenes (ClBzs), polychlorinated phenols (ClPhs), polybrominated phenols (BrPhs), polychlorinated biphenyls (PCBs) and polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs). Results show that the emission of chlorinated species is somewhat not affected by the chlorine content of the plastics mix. The production of PCBs and PCDD/Fs was very low, under 4 pg WHO-TEQ/g.
[en] Highlights: • Using high-resolution satellite image for detecting early-stage green tide • Found changing growth rate of green tide • Assessed the countermeasure of collecting floating-macroalgae at the initial sites - Abstract: The world's largest green tide originated from the Jiangsu Shoal of the Yellow Sea was due to fast reproduction of floating green macroalgae (Ulva prolifera). It brought significant impacts on marine environment and ecosystem in the Yellow Sea. In this study, we examined the expansion of green tide from the Jiangsu Shoal during the period from 29 April to 25 June 2016. Using high-resolution satellite images, we revealed a declined growth rate during the northward drifting of early-stage green tide for the first time, i.e., the green tide had higher growth rate (up to 25% per day) in the turbid waters of the Jiangsu Shoal in May and a lower growth rate (low to 3% per day) in the relatively clear waters in the middle of the western Yellow Sea in June, which suggests that water clarity might not be the key factor controlling the growth rate of the floating macroalgae in the surface waters under natural conditions. The high growth rate led to shortened time windows for controlling the green tide by employing macroalgae collecting campaigns at the initial sites of the green tide, which was no more than 14 days in the 2016 case.
[en] Highlights: • Species on transplanted pavers change most on rocky reefs close to the CBD. • Away from the CBD, point source pollution has effects compared to controls. • Restoration may not be possible in long-polluted parts of estuaries. - Abstract: Populations of macro-algae and sessile invertebrates have precipitously declined in urbanised coastal waters in Australia since European occupation. Responses of healthy subtidal sessile assemblages to cumulative impacts and types of urban impacts were measured in one of the most polluted estuaries in Australia - the Derwent Estuary - by transplanting sessile communities established on pavers to locations adjacent to marinas, sewerage outfalls, fish farm cages, and stormwater discharges, each with associated controls. Reef communities translocated to sites adjacent to central urban pollution sources (within 5 km of Hobart) lost canopy-forming algae. Fish farms, marinas, and storm water drains were all characterised by higher filamentous algal cover than their controls. Marinas were associated with losses in canopy and foliose algae. Restoration of subtidal reef near highly urbanised areas is unlikely to be successful until current pollution levels are dramatically reduced.
[en] Highlights: • Zostera noltei decline in the Arcachon Bay (southwest France) • Molecular effects of Copper and Pesticides cocktail used alone or mixed • Cu and Pesticides decreased the mitochondrial metabolism and photosynthesis - Abstract: Dwarf eelgrasses (Zostera noltei) populations have decreased since 2005 in Arcachon Bay (southwest France). Various stressors have been pointed out, however the role of xenobiotics like pesticides or copper (Cu) and of parameters like water temperature warming have not yet been explored. To determine their impact, Z. noltei individuals were collected in a pollution-free site and transferred to the laboratory in seawater microcosms. This dwarf eelgrass was exposed to a pesticide cocktail and copper, alone or simultaneously, at temperatures (10 °C, 20 °C, 28 °C) representative of different seasons. After a two-week contamination, leaf growth, leaf bioaccumulation of Cu, and differential expression of target genes were studied. Eelgrasses bioaccumulated Cu regardless of the temperature, with reduced efficiency in the presence of the Cu and pesticide cocktail at the two higher temperatures. High temperature also exacerbated the effect of contaminants, leading to growth inhibition and differential gene expression. Mitochondrial activity was strongly impacted and higher mortality rates occurred. Experimental results have been confirmed during field survey. This is the first report on the impacts on Z. noltei of pesticides and Cu associate to temperature.
[en] Highlights: • Vertical Hg profiles differed considerably between bare and vegetated sediments. • Mercury concentrations in bare-bottom sediments have reduced over time reflecting erosion and export of contaminant. • Salt marsh sediments were marked by a Hg sub-surface enrichment, with similar concentration and depth from 2007 onwards. • The persistency of Hg in the upper marsh layers highlights the complex recovery of historically contaminated marshes. - Abstract: During decades, mercury (Hg) was discharged into the Aveiro Lagoon. Twenty-five years after the cessation of discharges, sediment cores were collected at two areas to assess the evolution of the mercury contamination status. Vertical Hg profiles differed considerably between bare and vegetated sediments. Bare sediments contained significantly less Hg (−1) than historical data of 1995 (up to 40 mg kg−1), probably resulting from erosion. Salt marsh sediments were marked by a Hg sub-surface enrichment, reaching 44 mg kg−1 in the site closer to the industrial discharge point. High Hg concentrations in 2007, 2011 and 2016 were found at similar sediment layers. These results emphasise the role of halophyte plants in the cycling and retention of Hg in sediments. The persistency of high Hg in the upper marsh layers highlights the complexity in the recovery of historically contaminated marshes and the vulnerability to modifications in hydrology associated with climate changes.
[en] Highlights: • The aquaculture and industrial sewage impacts on benthic foraminifera investigated at two reefs across the northern Persian Gulf. • The stress-tolerant Quinqueloculina sp. and larger symbiont-bearing Amphistegina sp., was characteristic of the industrial sewaged reef. • The opportunistic species Ammonia sp. and Elphidium sp. were common in aquaculture sewaged reef. • The industrial sewaged reef displayed high FORAM Index (>4.0), reflecting favorable environments for supporting relatively healthy reefs. • FORAM Index in aquaculture sewaged reef ranged from 2.0 to 4.0 indicated that the water with organic pollution may support living coral community. - Abstract: The aquaculture and industrial sewage impacts on benthic foraminifera investigated at two reefs across the northern Persian Gulf. The foraminifera assemblages at a single sewaged reef were compared with two non-sewaged reefs. A low-diversity assemblage, dominated by stress-tolerant species Quinqueloculina sp. and larger symbiont-bearing Amphistegina sp., was characteristic of the industrial sewaged reef. The opportunistic species Ammonia sp. and Elphidium sp. were common in aquaculture sewaged reef. The density of foraminifera in sewaged reefs was lower than non-sewaged reefs. The lower diversity was only detected in the industrial sewaged reef. Assemblage structure was significantly different between sewaged and non-sewaged reefs. The industrial sewaged reef displayed high FORAM Index values (>4.0), reflecting favorable environments for supporting relatively healthy reefs. FORAM Index in aquaculture sewaged reef ranged from 2.0 to 4.0 indicated that the water with organic pollution may support living coral community, but any damage would not be followed by recovery.