خيارات البحث
النتائج 1741 - 1750 من 4,307
An ecotoxicological approach to evaluate the effects of tourism impacts in the Marine Protected Area of La Maddalena (Sardinia, Italy) النص الكامل
2017
Moschino, V. | Schintu, M. | Marrucci, A. | Marras, B. | Nesto, N. | Da Ros, L.
In the Marine Protected Area of La Maddalena Archipelago, environmental protection rules and safeguard measures for nautical activities have helped in reducing anthropogenic pressure; however, tourism related activities remain particularly significant in summer. With the aim of evaluating their impacts, the biomarker approach using transplanted Mytilus galloprovincialis as sentinel organisms coupled with POCIS deployment was applied. Mussels, translocated to four marine areas differently impacted by tourism activities, were sampled before, during and after the tourist season. Moreover, endocrine disruptors in passive samplers POCIS and the cellular toxicity of whole POCIS extracts on mussel haemocytes were evaluated to integrate ecotoxicological information. Lysosomal biomarkers, condition index and mortality rate, as well as metals in tissues suggested an alteration of the health status of mussels transplanted to the most impacted sites. The cellular toxicity of POCIS extracts was pointed out, notwithstanding the concentrations of the examined compounds were always below the detection limits.
اظهر المزيد [+] اقل [-]Estimating oil pollution risk in environmentally sensitive areas of petrochemical terminals based on a stochastic numerical simulation النص الكامل
2017
Xie, Cheng | Deng, Jian | Zhuang, Yuan | Sun, Hao
This paper presents a method based on the oceanic current model and the oil spill model to evaluate the pollution risk of sensitive resources when oil spills occur. Moreover, this study proposes a novel impact index based on the risk theory to improve the risk assessment accuracy. The impact probability and the first impact time of the oil spill are calculated through a stochastic numerical simulation. The risk assessment content is enriched by establishing an impact model that considers the impact of sensitive index and spillage. Finally, the risk score of sensitive resources in an oil spill accident is visualized for formulating a scientific and effective protection priority order in a contamination response strategy. This study focuses on integrating every possible impact factor that plays a role in risk assessment and helps to provide a better theoretical support for protecting sensitive resources.
اظهر المزيد [+] اقل [-]Near-surface distribution of pollutants in coastal waters as assessed by novel polyethylene passive samplers النص الكامل
2017
Aminot, Yann | Belles, Angel | Alary, Claire | Readman, James W.
We report a novel and inexpensive method to provide high resolution vertical measurements of temporally integrated organic contaminants in surface and sub-surface waters in polluted coastal environments. It employs a strip of polyethylene deployed as a passive sampler. Verifications are confirmed via conventional spot sample analyses and against Performance Reference Compound (PRC) calibration methods. Analytes targeted include 16 Polycyclic Aromatic Hydrocarbons, 15 personal care products, 8 organophosphorus flame retardants, 4 antifouling ‘booster’ biocides and 15 n-alkanes. Whilst all contaminants typically revealed homogeneous concentrations from 10 cm to 3 m depth in the selected harbour (<30% variations), many increased sharply at the air-sea interface. The passive sampler was shown to afford better resolution than could be achieved using conventional analytical techniques at the surface microlayer (SML). Whilst hydrophobicity appeared to be a key factor for the enrichment of many determinants, less correlation was found for the emerging contaminants.
اظهر المزيد [+] اقل [-]Litter assessment on 99 Cuban beaches: A baseline to identify sources of pollution and impacts for tourism and recreation النص الكامل
2017
Botero, C.M. | Anfuso, G. | Milanes, C. | Cabrera, A. | Casas, G. | Pranzini, E. | Williams, A.T.
Litter presence was assessed on the entire Cuban coastline, and includes 99 beaches from all Cuban regions, during field work carried out in 2012 and 2015. A standard method verified in several countries was applied, which classified beaches for nine types of litter into four grades (A-excellent to D-poor). Almost half of the Cuban beaches obtained excellent cleanliness scores, although many needed to be better managed. In this baseline, the most common types of residue were general litter (8% grade D and 35% grades B/C) and potentially harmful litter (<68% with grade A). Resort beaches and those with international visitors showed the best litter management. Tourism Impacts seems to be related to visitor origin therefore choices to develop sustainable tourism in rural and village beaches (64%) appears low, if beach cleaning gross investment is focused on resort beaches (24%). Finally, this paper highlights geographical distribution and types of litter patterns.
اظهر المزيد [+] اقل [-]Cluster analysis of aerosol properties retrieved from a sky-radiometer over a coastal site: Thiruvananthapuram, India النص الكامل
2017
Sateesh, M. | Soni, V.K. | Raju, P.V.S. | Mor, Vikram
The present work analysed the characteristics of aerosol optical, physical properties over Thiruvananthapuram, a coastal site in southern part of India using Sky-radiometer (Model POM-02, Prede Co. Ltd, Japan) for a period 2011–2015. The lowest value of AOD was found during winter season which was followed by monsoon season. The highest value of AOD was found in pre-monsoon. The Angstrom Exponent which characterizes the size of the aerosols, decreases from January to June and increases from June to December months. The monthly back trajectory analysis using HYSPLIT describes the source of air masses for the station. The fine mode particles are dominant during winter season, which may be associated with the anthropogenic emissions and long range transport. A gradual increase in the coarse mode aerosol load was found from pre-monsoon season to the monsoon season, because of the large air mass coming from the ocean. A decrease in coarse mode aerosol was found during the post-monsoon period, due to the preferential washout of coarse mode particles during monsoon season. The result showed the dominance of mixed type aerosols during all seasons. The C1 cluster originating from Bay of Bengal contributed 29.8% of ensemble of trajectories, C2 cluster from Arabian Sea 31.9%, C3 cluster from the Indian Ocean (Northern hemisphere) 18.0%, and C4 cluster Indian Ocean (Southern hemisphere) 20.3%.
اظهر المزيد [+] اقل [-]Seasonal changes of polycyclic aromatic hydrocarbons in response to hydrology and anthropogenic activities in the Pearl River estuary, China النص الكامل
2017
Liu, Feng | Niu, Lixia | Chen, Hui | Li, Ping | Tian, Feng | Yang, Qingshu
The behaviours of PAHs (containing 2–6 aromatic rings) in the Pearl River estuary were examined each month in 2011. This study was designed to investigate the abundance of 16 priority PAHs and their response to the seasonal dynamics of anthropogenic activities and hydrological cycles. Monthly mean concentrations of ∑16PAHs in water and suspended particulate matter (SPM) were 88.31ng/L and 252.31ng/L respectively, with higher concentrations in the wet season (April to September). Heavy precipitation in the wet season resulted in relatively increased PAH input via riverine discharges and atmospheric deposition. Seasonal variations in suspended sediment concentration (SSC), temperature and salinity have considerably affected the PAH phase association. Higher SSC in the wet season contributed to higher concentration of the PAHs in SPM, and higher temperature and lower salinity facilitated desorption from SPM. The PAH sources were largely attributed to vehicular emissions, coal combustion and coke ovens.
اظهر المزيد [+] اقل [-]Impacts of metal contamination and eutrophication on dinoflagellate cyst assemblages along the Guangdong coast of southern China النص الكامل
2017
Lu, Xinxin | Wang, Zhaohui | Guo, Xin | Gu, Yangguang | Liang, Weibiao | Liu, Lei
Fifty-one surface sediment samples were collected from eleven sea areas along the Guangdong coast in southern China. Biogenic elements, metals and dinoflagellate cysts were analyzed. Twenty-one cyst taxa in 12 genera were identified. The cyst concentrations ranged between 14 and 250 cysts/g, with an average of 69 cysts/g. The low cyst production was caused by coarse sediments, high sedimentation rates, and high anthropogenic disturbances. Biogenic elements were comparable with those reported. However, the metal concentrations were far lower than the sediment quality guidelines. Both biogenic elements and metals were higher in the Mid Coast and lower in the Western Coast. Eutrophication slightly enhanced the productivity of autotrophic dinocysts, and cysts of Scrippsiella indicated eutrophication. Cd had inhibitory effects on cyst production. Alexandrium and Diplopsalis cysts were sensitive to metal contamination; however, Gyrodinium, Pheopolykrikos, and Lingulodinium cysts had high resistance to metal contamination.
اظهر المزيد [+] اقل [-]Factors influencing organochlorine pesticides distribution in the Brisbane River Estuarine sediment, Australia النص الكامل
2017
Duodu, Godfred Odame | Goonetilleke, Ashantha | Ayoko, G. A. (Godwin A.)
Sediment samples collected from Brisbane River were analysed for organochlorine pesticide residues (OCPs). The factors influencing OCPs distribution in the sediment were investigated using multivariate analytical tools. Thirteen OCPs were detected in the sediment with concentrations ranging between below detection to 83.9ng/g, and detection frequency >90%. With the exception of dieldrin, the OCP inputs appear to be historical and may cause adverse ecological impacts. Multi-criteria ranking of the factors influencing the OCPs (except dieldrin) distribution in the sediment revealed that TOC>silt>intensive urban land use>population>seasons. Dieldrin distribution is significantly influenced by season>TOC>silt>intensive urban land use>population. The study helps to prioritise factors required for managing OCPs contamination in sediments and identification of appropriate mitigation measures.
اظهر المزيد [+] اقل [-]Potential impacts of shipping noise on marine mammals in the western Canadian Arctic النص الكامل
2017
Halliday, William D. | Insley, Stephen J. | Hilliard, R Casey | de Jong, Tyler | Pine, Matthew K.
As the Arctic warms and sea ice decreases, increased shipping will lead to higher ambient noise levels in the Arctic Ocean. Arctic marine mammals are vulnerable to increased noise because they use sound to survive and likely evolved in a relatively quiet soundscape. We model vessel noise propagation in the proposed western Canadian Arctic shipping corridor in order to examine impacts on marine mammals and marine protected areas (MPAs). Our model predicts that loud vessels are audible underwater when >100km away, could affect marine mammal behaviour when within 2km for icebreakers vessels, and as far as 52km for tankers. This vessel noise could have substantial impacts on marine mammals during migration and in MPAs. We suggest that locating the corridor farther north, use of marine mammal observers on vessels, and the reduction of vessel speed would help to reduce this impact.
اظهر المزيد [+] اقل [-]Effects of seawater pH and temperature on foraging behavior of the Japanese stone crab Charybdis japonica النص الكامل
2017
Wu, Fangli | Wang, Ting | Cui, Shuaikang | Xie, Zhe | duPont, Sam | Zeng, Jiangning | Gu, Huaxin | Kong, Hui | Hu, Menghong | Lu, Weiqun | Wang, Youji
We examined prey selection and foraging behaviors of the crab Charybdis japonica exposed to four combinations of pH (7.3 and 8.1) and temperature (18°C and 25°C). The order of prey selection by C. japonica was Potamocorbula laevis, Ruditapes philippinarum, Tegillarca granosa and Mactra veneriformis. Under high pCO2, times for searching, breaking, eating and handling were all significantly longer than those at the normal pCO2, and the prey profitability and predation rate under high pCO2 were significantly lower than normal pCO2. Moreover, temperature significantly influenced the foraging behaviors, but its effects were not as strong as those of pH; times for searching, eating and handling under high temperature were significantly lower than the low temperature, and the prey predation rates under high temperature was significantly higher than low temperature. In conclusion, high pCO2 negatively affected the foraging behavior, but high temperature actively stimulated the foraging behaviors of crabs.
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