خيارات البحث
النتائج 1281 - 1290 من 4,045
Environmental sensitivity mapping and risk assessment for oil spill along the Chennai Coast in India النص الكامل
2016
Kankara, R.S. | Arockiaraj, S. | Prabhu, K.
Integration of oil spill modeling with coastal resource information could be useful for protecting the coastal environment from oil spills. A scenario-based risk assessment and sensitivity indexing were performed for the Chennai coast by integrating a coastal resource information system and an oil spill trajectory model. The fate analysis of spilled oil showed that 55% of oil out of a total volume of 100m3 remained in the water column, affecting 800m of the shoreline. The seasonal scenarios show major impact during the southwest (SW) and northeast (NE) monsoons and more fatal effects on marine pelagic organisms during SW monsoon. The Oil Spill Risk Assessment Modeler tool was constructed in a geographic information systems (GIS) platform to analyze the risks, sensitivity mapping, and priority indexing of resources that are likely to be affected by oil spills along the Chennai coast. The results of sensitivity mapping and the risk assessment results can help organizations take measures to combat oil spills in a timely manner.
اظهر المزيد [+] اقل [-]Testing the efficiency of temperate benthic biotic indices in assessing the ecological status of a tropical ecosystem النص الكامل
2016
Sivadas, Sanitha K. | Nagesh, Rahul | Gupta, G.V.M. | Gaonkar, Udaykumar | Mukherjee, Indranil | Ramteke, Darwin | Ingole, Baban S.
The objectives of the present study were to evaluate the ecological status of tropical coastal waters using the temperate benthic indices and examine the effect of seasonal variability on the performance of benthic indices. Macrobenthic samples were collected from northwest to southeast coast of India during 2003–2012 and we tested different univariate indices, ecological strategies, indicator species and multimetric indices. AMBI and multimetric indices performed satisfactorily in evaluating the ecological status. Seasonal variability on the biotic indices was observed during the southwest monsoon and fall intermonsoon period due to recruitment. Therefore, we recommended the non-monsoon period (January–May) as a suitable time of the year to use the indices for effective assessment of the Indian coastal waters. Results show that, the temperate benthic indices are efficient in assessing the tropical environmental status. However, complementary use of different indices is suggested for accurate assessment of the environmental status.
اظهر المزيد [+] اقل [-]Distribution of 137Cs in the Mediterranean mussel (Mytilus galloprovincialis) in Eastern Black Sea Coast of Turkey النص الكامل
2016
Baltas, H. | Kiris, E. | Dalgic, G. | Cevik, U.
This study presents the results of 137Cs and 40K radionuclide concentrations in mussel (Mytilus galloprovincialis) samples collected during the period of February–November 2014 from twelve different stations within the border of the eastern Black Sea region of Turkey. Also, these radionuclide concentrations were determined in sea water and sediment samples. The activity concentrations in seawater, sediment and mussel tissue samples were between 1.12–1.69mBqL−1, 3.26–30.74 and 1.61–3.16Bqkg−1 for 137Cs and 231.41–399.49mBqL−1, 215.71–450.07 and 286.84–382.16Bqkg−1 for 40K, respectively. These values are also in accordance with the concentrations reported for similar regions. Additionally, radiological impact parameters such as daily intake of 137Cs and 40K, annual committed effective dose and carcinogenic risk due to the consumption of mussel were calculated and compared with the international data. Lifetime cancer risk values are lower than the limit of 10−3.
اظهر المزيد [+] اقل [-]Characteristics of haze weather in Chongqing, China and its determinants analysis based on automatic monitoring stations النص الكامل
2016
Li, Mingsheng | Jia, Lin | Zhang, Fengying | Hu, Maogui | Shi, Yu | Chen, Xi
Statistical analyses were carried out on the characteristics of haze weather and their relation with air quality and meteorological factors using data recorded by the national air quality and meteorological monitoring network of Chongqing, China in 2013. The results showed that the hourly occurrence rate of haze in Chongqing was 81.3% and that 67.2% of the total number of haze hours was at the level of mild to light haze. Haze was more likely to occur in autumn and winter (67.2% of the total number of hours; occurrence rate 97.5%) and was more likely to occur between 22:00 and 10:00. Haze mainly occurred when the wind speed was <1.2 m s−1 and the relative humidity was >50%. Haze rarely occurred when the wind speed was >3.0 m s−1 and the relative humidity was <30%. There was a positive correlation between temperature and visibility. The occurrence rate was higher with positive variations in the 24-h temperature records. The main factor affecting haze was the level of PM2.5 pollution. Haze mainly occurred when ρ(PM2.5) was between 35 and 250 μg m−3, accounting for 86.4% of the total number of hours of haze. When ρ(PM2.5) was >75 μg m−3, the occurrence rate of haze was 100.0%. The mean value of ρ(PM2.5)/ρ(PM10) during the hours of haze was 72.9%, 17.7% higher than that at other times. The number of hours with air pollution accounted for 48.8% of the total number of hours, far less than the occurrence of haze. When the ambient air quality was excellent or good, haze was present in 65.4% of hours. We suggest that there are differences between the assessment of air quality and the definition of haze used in China. The relationship between haze and air quality would be better matched if we used the World Meteorological Organization's definition of haze (visibility < 5.0 km).
اظهر المزيد [+] اقل [-]Mercury concentrations in Alaska Pacific halibut muscle relative to stable isotopes of C and N and other biological variables النص الكامل
2016
Bentzen, Rebecca | Castellini, J Margaret | Gerlach, Robert | Dykstra, Claude | O'Hara, Todd
Total mercury concentrations ([THg]), δ15N and δ13C values were determined in muscle of 693 Pacific halibut caught in International Pacific Halibut Commission setline surveys in Alaska (2002−2011). Project goals were to evaluate whether 1) δ15N and δ13C varied with region, age, sex and length of halibut, and 2) muscle [THg] varied with δ15N and δ13C (feeding ecology) while accounting for sex, length, and region. Variation in [THg] was explained, in part, by halibut feeding ecology as [THg] increased with trophic position (increasing δ15N). Halibut from the western Aleutian Island region were the exception, with overall lower δ15N values and significantly higher [THg] than halibut from other Alaskan waters. This [THg] pattern has been observed in other Aleutian biota, possibly the result of northeasterly atmospheric movement of mercury emissions from Asia and/or other local sources and processes. The significantly lower δ15N values for these halibut warrants further investigation of halibut prey.
اظهر المزيد [+] اقل [-]Current status of coral reefs in the United Arab Emirates: Distribution, extent, and community structure with implications for management النص الكامل
2016
Grizzle, Raymond E. | Ward, Krystin M. | AlShihi, Rashid M.S. | Burt, John A.
Coral reefs of the United Arab Emirates were once extensive, but have declined dramatically in recent decades. Marine management and policy have been hampered by outdated and inaccurate habitat maps and habitat quality information. We combined existing recent datasets with our newly mapped coral habitats to provide a current assessment of nation-wide extent, and performed quantitative surveys of communities at 23 sites to assess coral cover and composition. Over 132km2 of coral habitat was mapped, averaging 28.6±3.8% live coral cover at surveyed sites. In the Arabian Gulf low cover, low richness Porites dominated communities characterized western Abu Dhabi, while reefs northeast of Abu Dhabi city generally contained higher richness and cover, and were dominated by merulinids (formerly faviids). Distinct communities occur in the Sea of Oman, where cover and richness were low. We provide management recommendations to enhance conservation of vulnerable coral reefs in the UAE.
اظهر المزيد [+] اقل [-]Investigation on the differences of accumulating Escherichia coli in three types of shellfish species, involving in the environmental factors النص الكامل
2016
Jin, Lei | Li, Tiejun | Liu, Huan | Zhu, Jinping
This study investigated accumulation of Escherichia coli and aerobic colony count in three types of shellfish species. The results indicated that the capability of accumulating E. coli and aerobic colony count for Sinonovacula constricta was stronger than that for Meretrix meretrix and Tegillarca granosa, and capability of accumulating E. coli for M. meretrix was slightly stronger than that for T. granosa. However, no significant difference was observed in the capability of accumulating aerobic colony count between M. meretrix and T. granosa. Moreover, accumulation of E. coli in S. constricta is affected by contaminated seawater and E. coli were accumulated much faster and more in S. constricta when the seawater contaminated more serious. Meanwhile, the results suggested that the populations of E. coli in S. constricta changed in accordance with the weather. This is the first study to investigate the differences of accumulating E. coli in three types of shellfish species.
اظهر المزيد [+] اقل [-]New direction for environmental water management النص الكامل
2016
Tomita, Akio | Nakura, Yoshio | Ishikawa, Takuya
Japan experienced severe environmental problems including water pollution and damages to aquatic organisms and fishery industry through and after the high economic growth period in the 1960s.One of the countermeasures to address these problems was the Total Pollutant Load Control System (TPLCS), which has been implemented with the aim of reducing the total amount of pollutant loads, specifically targeting Chemical Oxygen Demand (COD), total nitrogen and total phosphorus.The TPLCS has significantly improved the quality of the coastal sea water. However, while the accumulated pollutant loads from the past industrialization have still remained, new environmental concerns have arisen. Our new environmental policies are thus to deal with conservation of biological diversity and other related marine environmental issues.Japan has entered a new phase of environmental management, setting the new direction and framework toward a beautiful, bio-diverse, bustling-with-people and bountiful sea.
اظهر المزيد [+] اقل [-]Histopathological and apoptotic changes on marine mussels Mytilus galloprovincialis (Lamark, 1819) following exposure to environmental pollutants النص الكامل
2016
Yavaşoğlu, Altuğ | Özkan, Dilara | Güner, Adem | Katalay, Selma | Oltulu, Fatih | Yavaşoğlu, NÜlkü Karabay
Marine bivalve mussels, especially Mytilus species are an earlywarning system used for determining of damage caused by the various aquatic pollutions. In the present study, Mytilus galloprovincialis L. (black mussel) have been utilised as a biomonitoring organism to reveal environmental pollution in the Aliaga, Foca and Urla where located along the Izmir Coast of Turkey. Mussels were collected at these areas and gill and hepatopancreas (digestive gland) tissues were excised. mRNA expressions of initiator (caspase-2 and −8) and executioner (caspase −3/7–1, −3/7–2, −3/7–3 and −3/7–4) caspases of mussels tissues in areas exposed to pollution agent have been observed. TUNEL immunoreactivity in paralel to histopathological changes in both Aliaga and Foca areas were compared with Urla. This study is the first report to reveal the pollution with apoptotic expression on mussels in the coast of Turkey.
اظهر المزيد [+] اقل [-]Ontogenetic variability in the feeding behavior of a marine amphipod in response to ocean acidification النص الكامل
2016
Benítez, Samanta | Duarte, Cristian | López, Jorge | Manríquez, Patricio H. | Navarro, Jorge M. | Bonta, Cesar C. | Torres, Rodrigo | Quijón, Pedro A.
Global stressors like ocean acidification (OA) are expected to influence the quality or palatability of primary producers like algae. Such changes can trigger a response on algal consumers' feeding strategies, and this response may not necessarily be the same for the consumers during the ontogeny. We used a mesocosm's system to expose algae to current and projected OA conditions (390 and 1000ppm, respectively) and then compared the feeding behavior and absorption efficiency of juvenile and adult stages of the amphipod Orchestoidea tuberculata. Specifically, we measured consumption rates (with and without a choice) and absorption efficiency on algae exposed and not exposed to OA. Our results show that OA affect the amphipod's consumption and feeding preferences, and that these effects were related with the analyzed ontogenetic stage (juveniles versus adults). These results support the existence of an ontogenetic change in the response of this species and others similar marine invertebrates to OA, which highlight the need to incorporate different life stages in the study of OA or others global stressors.
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