خيارات البحث
النتائج 841 - 850 من 2,513
Surfactants in the sea-surface microlayer and atmospheric aerosol around the southern region of Peninsular Malaysia النص الكامل
2014
This study was conducted to determine the composition of surfactants in the sea-surface microlayer (SML) and atmospheric aerosol around the southern region of the Peninsular Malaysia. Surfactants in samples taken from the SML and atmospheric aerosol were determined using a colorimetric method, as either methylene blue active substances (MBAS) or disulphine blue active substances (DBAS). Principal component analysis with multiple linear regressions (PCA–MLR), using the anion and major element composition of the aerosol samples, was used to determine possible sources of surfactants in atmospheric aerosol. The results showed that the concentrations of surfactants in the SML and atmospheric aerosol were dominated by anionic surfactants and that surfactants in aerosol were not directly correlated (p>0.05) with surfactants in the SML. Further PCA–MLR from anion and major element concentrations showed that combustion of fossil fuel and sea spray were the major contributors to surfactants in aerosol in the study area.
اظهر المزيد [+] اقل [-]Major factors influencing the elemental composition of surface estuarine sediments: The case of 15 estuaries in Portugal النص الكامل
2014
(Pedro José Silva),
Upper sediments (0–5cm) were sampled in 94 sites of water bodies of the fifteen Portuguese estuaries characterized by distinct settings of climate, topography and lithology, and marked by diverse anthropogenic pressures. Confined areas recognized as highly anthropogenic impacted, as well as areas dominated by erosion or frequently dredged were not sampled. Grain size, organic carbon (Corg), Al and trace elements (As, Cd, Co, Cr, Cu, Hg, Ni, Pb and Zn) were determined. Normalisation of trace element concentrations to Al and Corg, correlations between elements and Principal Component Analysis (PCA) allowed identifying elemental associations and the relevance of grain-size, lithology and anthropogenic inputs on sediment chemical composition. Whereas grain-size is the dominant effect for the majority of the studied estuaries, the southern estuaries Mira, Arade and Guadiana are dominated by specific lithologies of their river basins, and anthropogenic effects are identified in Ave, Leça, Tagus and Sado. This study emphasizes how baseline values of trace elements in sediments may vary within and among estuarine systems.
اظهر المزيد [+] اقل [-]Isolation and characterization of a novel hydrocarbon-degrading bacterium Achromobacter sp. HZ01 from the crude oil-contaminated seawater at the Daya Bay, southern China النص الكامل
2014
Deng, Mao-Cheng | Li, Jing | Liang, Fu-Rui | Yi, Meisheng | Xu, Xiao-Ming | Yuan, Jian-Ping | Peng, Juan | Wu, Chou-Fei | Wang, Jiang-Hai
Microorganisms play an important role in the biodegradation of petroleum contaminants, which have attracted great concern due to their persistent toxicity and difficult biodegradation. In this paper, a novel hydrocarbon-degrading bacterium HZ01 was isolated from the crude oil-contaminated seawater at the Daya Bay, South China Sea, and identified as Achromobacter sp. Under the conditions of pH 7.0, NaCl 3% (w/v), temperature 28°C and rotary speed 150rpm, its degradability of the total n-alkanes reached up to 96.6% after 10days of incubation for the evaporated diesel oil. Furthermore, Achromobacter sp. HZ01 could effectively utilize polycyclic aromatic hydrocarbons (PAHs) as its sole carbon source, and could remove anthracene, phenanthrene and pyrence about 29.8%, 50.6% and 38.4% respectively after 30days of incubation. Therefore, Achromobacter sp. HZ01 may employed as an excellent degrader to develop one cost-effective and eco-friendly method for the bioremediation of marine environments polluted by crude oil.
اظهر المزيد [+] اقل [-]Ballast water: A threat to the Amazon Basin النص الكامل
2014
Pereira, Newton Narciso | Botter, Rui Carlos | Folena, Rafael Dompieri | Pereira, José Pinheiro Fragoso Neto | da Cunha, Alan Cavalcanti
Ballast water exchange (BWE) is the most efficient measure to control the invasion of exotic species from ships. This procedure is being used for merchant ships in national and international voyages. The ballast water (BW) salinity is the main parameter to evaluate the efficacy of the mid-ocean ballast water exchange. The vessels must report to the Port State Control (PSC), via ballast water report (BWR), where and how the mid-ocean BWE was performed. This measure allows the PSC to analyze this information before the ship arrives at the port, and to decide whether or not it should berth.Ship BW reporting forms were collected from the Captaincy of Santana and some ships were visited near the Port of Santana, located in Macapá (Amazon River), to evaluate the BW quality onboard. We evaluated data submitted in these BWR forms and concluded that the BWE efficacy might be compromised, because data contained in these BWR indicate that some ships did not change their BW. We found mistakes in filling the BWR forms and lack of information. Moreover, these ships had discharged BW with high level of salinity, Escherichia coli and total coliforms into the Amazon River. We concluded that the authorities of the Amazon Region need to develop more efficient proceedings to evaluate the ballast water reporting forms and BW quality, as there is potential risk of future invasion of exotic species in Brazilian ports.
اظهر المزيد [+] اقل [-]PM10 black carbon and ionic species concentration of urban atmosphere in Makassar of South Sulawesi Province, Indonesia النص الكامل
2014
Rashid, Mohd | Yunus, Sattar | Mat, Ramli | Baharun, Sabariah | Lestari, Puji
This paper presents a study on black carbon and ionic species concentrations in PM10, sampled from the urban area of Makassar in the Province of South Sulawesi, Indonesia. The samples were collected on a weekly basis within a period of one year from February 2012 to January 2013. Results showed that the mean concentration of PM10 black carbon was 2.01±0.93μg/m3, while ionic species concentrations were found in descending order; SO42−>NO3−>Cl−>NH4+, with mean concentrations of 1.44±1.04μg/m3, 1.11±1.06μg/m3, 0.87±0.91μg/m3, 0.49±0.64μg/m3, respectively. Black carbon concentration was higher during the dry months, which may be attributed to uncontrolled biomass burning during hot and dry weather conditions. Similarly, SO42− and NH4+ concentrations were higher during the dry month seasons. On the contrary, Cl− concentration was higher during the wet months, influenced by the marine environment surrounding the area.
اظهر المزيد [+] اقل [-]Managing ocean information in the digital era – Events in Canada open questions about the role of marine science libraries النص الكامل
2014
Wells, P. G.
Information is the foundation of evidence-based policies for effective marine environmental protection and conservation. In Canada, the cutback of marine science libraries introduces key questions about the role of such institutions and the management of ocean information in the digital age. How vital are such libraries in the mission of studying and protecting the oceans? What is the fate and value of the massive grey literature holdings, including archival materials, much of which is not in digital form but which often contains vital data? How important is this literature generally in the marine environmental sciences? Are we likely to forget the history of the marine pollution field if our digital focus eclipses the need for and access to comprehensive collections and skilled information specialists? This paper explores these and other questions against the backdrop of unprecedented changes in the federal libraries, marine environmental science and legislation in Canada.
اظهر المزيد [+] اقل [-]Multiple stressors threatening the future of the Baltic Sea–Kattegat marine ecosystem: Implications for policy and management actions النص الكامل
2014
Jutterström, S. | Andersson, H.C. | Omstedt, A. | Malmaeus, J.M.
The paper discusses the combined effects of ocean acidification, eutrophication and climate change on the Baltic Sea and the implications for current management strategies. The scientific basis is built on results gathered in the BONUS+ projects Baltic-C and ECOSUPPORT. Model results indicate that the Baltic Sea is likely to be warmer, more hypoxic and more acidic in the future. At present management strategies are not taking into account temporal trends and potential ecosystem change due to warming and/or acidification, and therefore fulfilling the obligations specified within the Marine Strategy Framework Directive, OSPAR and HELCOM conventions and national environmental objectives may become significantly more difficult. The paper aims to provide a basis for a discussion on the effectiveness of current policy instruments and possible strategies for setting practical environmental objectives in a changing climate and with multiple stressors.
اظهر المزيد [+] اقل [-]Screening of biosurfactant producers from petroleum hydrocarbon contaminated sources in cold marine environments النص الكامل
2014
Cai, Qinhong | Zhang, Baiyu | Chen, Bing | Zhu, Zhiwen | Lin, Weiyun | Cao, Tong
An overview of literature about isolating biosurfactant producers from marine sources indicated no such producers have been reported form North Atlantic Canada. Water and sediment samples were taken from petroleum hydrocarbon contaminated coastal and offshore areas in this region. Either n-hexadecane or diesel was used as the sole carbon source for the screening. A modified colony-based oil drop collapsing test was used to cover sessile biosurfactant producers. Fifty-five biosurfactant producers belong to genera of Alcanivorax, Exiguobacterium, Halomonas, Rhodococcus, Bacillus, Acinetobacter, Pseudomonas, and Streptomyces were isolated. The first three genera were established after 1980s with interesting characteristics and limited relevant publications. Some of the 55 isolated strains were found with properties such as greatly reducing surface tension, stabilizing emulsion and producing flocculant. Isolates P6-4P and P1-5P were selected to demonstrate the performance of biosurfactant production, and were found to reduce the surface tension of water to as low as 28dynes/cm.
اظهر المزيد [+] اقل [-]Growth, nutrient status, and photosynthetic response to diesel-contaminated soil of a cordgrass, Spartina argentinensis النص الكامل
2014
Redondo-Gómez, Susana | Petenello, María C. | Feldman, Susana R.
The present study was conduced to investigate the tolerance limits of Spartina argentinensis, which occurs in inland marshes of the Chaco-Pampean regions of Argentina, to diesel-contaminated soil. A glasshouse experiment was designed to investigate the effect of diesel fuel from 0% to 3% on growth and photosynthetic apparatus of S. densiflora by measuring gas exchange and photosynthetic pigments. We also performed chemical analysis of plant samples, and determined mycorrhizal index. Tiller and root biomasses declined with increasing diesel fuel concentration, as well as photosynthetic rate (A). Reductions in A could be accounted for by non-stomatal limitations. Mycorrhizal roots of S. argentinensis were reduced by the presence of diesel fuel, but did not affect its nutritional status; in fact, most element concentrations increased with diesel contamination. Despite the negative effect of diesel-contaminated soil, S. argentinensis continued growing, which could be useful management options for phytorremediation of diesel-contaminated soils.
اظهر المزيد [+] اقل [-]Influence of urban runoff, inappropriate waste disposal practices and World War II on the heavy metal status of sediments in the southern half of Saipan Lagoon, Saipan, CNMI النص الكامل
2014
Denton, Gary R.W. | Emborski, Carmen A. | Habana, Nathan C. | Starmer, John A.
Heavy metals were examined in sediments from the southern half of Saipan Lagoon. These waters provided tactical access for US troops during WWII and were heavily shelled at the time. Mercury profiles in sediments were, to some extent, reflective of this event. Samples from the southern end of the lagoon, where an old post-war dumpsite once existed, were found to be substantially enriched with Pb, Cu and Zn. Further north, the lagoon was primarily impacted by urban runoff. Metal enrichment in sediments from this region was generally highest at storm drain outlets and attenuated seawards. Moderate enrichment was rarely exceeded for any element other than Hg beyond the 50m mark. Sediment quality guidelines used to flag potentially adverse ecological health effects revealed no PEL exceedances. TEL exceedances for Pb and Cu were identified in sediments near the former dumpsite. The public health implications of the data are briefly addressed.
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