خيارات البحث
النتائج 731 - 740 من 3,208
Changes in abundance and composition of anthropogenic marine debris on the continental slope off the Pacific coast of northern Japan, after the March 2011 Tohoku earthquake النص الكامل
2015
Goto, Tomoaki | Shibata, Haruka
Abundance and composition of anthropogenic marine debris were assessed on the basis of six bottom trawl surveys conducted on the continental slope off Iwate Prefecture, Pacific coast of northern Japan, in 2003, 2004 and 2011, and the temporal changes due to the Tohoku earthquake and tsunami in March 2011 evaluated. In 2003 and 2004, 54–94 items km−2 of marine debris, dominated by sea-base sourced items mainly comprising fishing gear and related items from adjacent fishing grounds on the continental shelf, were quantified. In the post-earthquake period, the density increased drastically to 233–332 items km−2, due to an increase in land-base sourced items generated by the tsunami. However, a major increase in abundance after the disaster, compared to the total amount of tsunami debris swept into the sea, was not found. Additional sources of land-based debris from the adjacent continental shelf are suggested in the present waters.
اظهر المزيد [+] اقل [-]Near-road measurements for nitrogen dioxide and its association with traffic exposure zones النص الكامل
2015
Smith, Luther | Mukerjee, Shaibal | Kovalcik, Kasey | Sams, Elizabeth | Stallings, Casson | Hudgens, Edward | Scott, James | Krantz, Todd | Neas, Lucas
Near-road measurements for nitrogen dioxide (NO2) using passive air samplers were collected weekly in traffic exposure zones (TEZs) in the Research Triangle area of North Carolina (USA) during Fall 2014. Land use regression (LUR) analysis and pairwise comparisons of TEZs showed NO2 concentrations were associated with TEZs. Greater NO2 levels occurred in delay, high volume, and bus route sections versus higher signal light density, urbanized, and “remainder of study” areas. Comparison of near-road passively sampled NO2 concentrations by TEZ agreed with previous real-time on-road comparisons for NO2 in these TEZs.
اظهر المزيد [+] اقل [-]Estimation of hydrogen sulfide removal efficiency with granulated coal ash applied to eutrophic marine sediment using a simplified simulation model النص الكامل
2015
Asaoka, Satoshi | Yamamoto, Tamiji | Yamamoto, Hironori | Okamura, Hideo | Hino, Kazutoshi | Nakamoto, Kenji | Saito, Tadashi
Hydrogen sulfide generated in eutrophic marine sediment is harmful for living organisms. It is therefore necessary to remove hydrogen sulfide from the sediment to restore benthic ecosystems. Previous studies revealed that granulated coal ash, which is a by-product of coal thermal electric power stations, could remove and oxidize hydrogen sulfide. In this study, we propose a simplified simulation model to estimate the hydrogen sulfide removal efficiency of granulated coal ash. Hydrogen sulfide concentrations in eutrophic marine sediment pore water with and without the application of granulated coal ash were calculated by the proposed model, and the outputs were compared with semi-field or field observation data. The model outputs reproduced the observed data well. Using the proposed model outputs, we suggest an optimum application dosage of granulated coal ash for remediating eutrophic marine sediment.
اظهر المزيد [+] اقل [-]Analysis of chloramphenicol residues in the macroalgae Ulva lactuca through ultra-high performance liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS) النص الكامل
2015
Leston, Sara | Freitas, Andreia | Nunes, Margarida | Barbosa, Jorge | Pardal, Miguel Ângelo | Ramos, Fernando
Antibiotic use is a well-described practice to promote animal health whether for prevention or treatment. Nonetheless, it can also cause a number of potentially harmful effects that dictate the need to implement regulation to assure a reduction of hazards to the consumers and the environment. Chloramphenicol (CAP) is a broad-spectrum antibacterial excluded from use in animal food production but despite this, reports of illegal use still persist. More recently, awareness has risen that the surrounding natural ecosystems can potentially be contaminated by pharmaceuticals and the extent of their effects in non-target organisms is already under the scope of researchers. To face the demanding new challenges a methodology for the determination of CAP in the green macroalgae Ulva lactuca by ultra-high performance liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS) was developed, optimized and fully validated following the guidelines of the EC Decision 2002/657.
اظهر المزيد [+] اقل [-]Climatic impact on community of filamentous macroalgae in the Neva estuary (eastern Baltic Sea) النص الكامل
2015
Gubelit, Yulia I.
In presented study the impact of climatic factors and North Atlantic Oscillation (NAO) on macroalgal community was analysed. Also the factors influencing algal community were defined with help of Principal Component and Classification analysis. It was found that climatic impact may depend on habitat features and that on different sites biomass of macroalgae correlated with different weather factors. Wind and surf may affect biomass of macroalgae adversely on some sites and at the same time on other sites they may accumulate biomass, transferring it is from adjacent areas. High direct correlation with temperature was found on sites which were protected from surf and had no stagnant events. Seasonal biomass inversely significantly correlated with average seasonal wind speed and annual NAO-index.
اظهر المزيد [+] اقل [-]Anthropogenic impacts on meiobenthic Ostracoda (Crustacea) in the moderately polluted Kasado Bay, Seto Inland Sea, Japan, over the past 70 years النص الكامل
2015
Irizuki, Toshiaki | Ito, Hisayo | Sako, Megumi | Yoshioka, Kaoru | Kawano, Shigenori | Nomura, Ritsuo | Tanaka, Yuichiro
Two sediment cores were obtained from Kasado Bay, a moderate-polluted enclosed bay in Japan, to examine anthropogenic impacts on Ostracoda over the past ca. 70years. We analyzed ostracode abundance and diversity, grain size, and CHN, and used 210Pb and 137Cs as the dating method. The present study showed that cross-plot comparisons of ostracode abundance and each environmental factor, based on sediment core data, could be used to identify ostracode species as indicators for anthropogenic influences. Ostracode abundance reflected mainly the changes that had occurred in total organic carbon content in sediments related to eutrophication, but heavy metal concentration did not directly influence several ostracode abundance in the bay. Environmental deterioration because of eutrophication started in the 1960s. The regulations regarding the chemical oxygen demand in waters introduced in the 1980s probably influence ostracode abundance for certain species in this period. Currently, Kasado Bay is not experiencing severe degradation.
اظهر المزيد [+] اقل [-]The nutrient, total petroleum hydrocarbon and heavy metal contents in the seawater of Bohai Bay, China: Temporal–spatial variations, sources, pollution statuses, and ecological risks النص الكامل
2015
Peng, Shitao
Seawater samples collected between 2007 and 2012 were determined the concentrations of nutrient (DIN and DIP), total petroleum hydrocarbon (TPH), and six different heavy metals (As, Cu, Zn, Pb, Cd and Hg). The DIN, DIP, TPH, Pb, and Cd concentrations decreased from 2007 to 2009 or 2010 and increased after 2010. However, the Hg and Cu concentrations increased from 2007 to 2012. In contrast, the As and Zn gradually decreased during the study period. All of the pollutant concentrations gradually decreased from the shoreline to the offshore sites. PCA result showed that urban and port areas, agriculture, and atmospheric deposition were the main sources of pollutants in the bay. Although most of the pollutants were present at concentrations bellow the highest seawater quality standards in China, eutrophication was a risk in Bohai Bay. In addition, DIN was the main pollutant and was responsible for the eutrophication risk in Bohai Bay.
اظهر المزيد [+] اقل [-]Marine debris ingestion by sea turtles (Testudines) on the Brazilian coast: an underestimated threat? النص الكامل
2015
de Carvalho, Robson Henrique | Lacerda, Pedro Dutra | da Silva Mendes, Sarah | Barbosa, Bruno Corrêa | Paschoalini, Mariana | Prezoto, Fabio | de Sousa, Bernadete Maria
Assessment of marine debris ingestion by sea turtles is important, especially to ensure their survival. From January to December 2011, 23 specimens of five species of sea turtles were found dead or dying after being rehabilitated, along the coast of the municipality of Rio de Janeiro, Brazil. To detect the presence of marine debris in the digestive tract of these turtles, we conducted a postmortem examination from the esophagus until the distal portion of the large intestine for each specimen. Of the total number of turtles, 39% had ingested marine debris such as soft plastic, hard plastic, metal, polyethylene terephthalate (PET) bottle caps, human hair, tampons, and latex condoms. Five of the seven sea turtles species are found along the Brazilian coast, where they feed and breed. A large number of animals are exposed to various kinds of threats, including debris ingestion.
اظهر المزيد [+] اقل [-]Metal(loid)s in sediment, lobster and mussel tissues near historical gold mine sites النص الكامل
2015
Walker, Tony R. | Grant, Jon
Previous studies near historical gold mining districts in Nova Scotia have identified significant enrichment of metal(loid)s in coastal marine sediments. Most of this inventory is buried below biologically active zones, although in some areas arsenic has bioaccumulated in marine biota resulting in localised bivalve shellfish closures. Isaacs Harbour is poised for future industrial development, but before potential impacts are predicted, current marine baseline conditions must be determined. To address this gap, this study established a baseline using surface sediments and biota (mussel and lobster tissues), to provide a broader picture of metal(loid)s in the marine environment. Results confirmed previous studies showing that most sediment metal(loid) concentrations still exceeded Canadian Marine Sediment Quality Guidelines, and also provided evidence of Canadian Food Inspection Agency fish tissue exceedances of arsenic in lobster and lead in mussel tissues indicating that some bioaccumulation of legacy contaminants in marine biota continues to the present day.
اظهر المزيد [+] اقل [-]Heavy metals distribution and environmental quality assessment for sediments off the southern coast of the Shandong Peninsula, China النص الكامل
2015
Liu, Shanshan | Zhang, Yong | Bi, Shipu | Zhang, Xiaobo | Li, Xiaoyue | Lin, Manman | Hu, Gang
A systematic study was conducted on the distribution characteristics of heavy metals and on associated influencing factors in sediments off the southern coast of the Shandong Peninsula, China, based on the results of a heavy metals analysis on 157 surface sediment samples from coastal waters of the study area and on 46 samples from surrounding rivers flowing into the sea. An environmental quality assessment of heavy metals was performed using the Nemerow index. The results show that the distribution characteristics of sediment heavy metals in coastal waters outside of Qingdao can be divided into three classes: (1) Class I – Cr, Cu and Zn, with high-value areas extending from the northeast to the southwest in a banded or tongue-like pattern; (2) Class II – As, Cd and Pb, with high-value areas mainly distributed off the southeastern coast of Mt. Lao; and (3) Class III – Hg only, with high-value areas mainly in the northern area of Jiaozhou Bay. Integrated assessment based on the Nemerow index reveals that heavy metals pollution has occurred in surface sediments in a number of coastal water areas outside of Qingdao. This pollution is mainly found off the southeastern coast of Mt. Lao and in the northeastern section of Jiaozhou Bay. Results show that grain size of surface sediments, surrounding rivers and human activities are the main reasons for the element distribution pattern.
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