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结果 1411-1420 的 4,042
A multidisciplinary approach for the characterization of the coastal marine ecosystems of Monte Di Procida (Campania, Italy) 全文
2016
Mangoni, Olga | Aiello, G. (Giuseppe) | Balbi, Simona | Barra, Diana | Bolinesi, Francesco | Donadio, Carlo | Ferrara, Luciano | Guida, Marco | Parisi, Roberta | Pennetta, Micla | Trifuoggi, Marco | Arienzo, Michele
A multidisciplinary survey was carried out on the quality of water and sediments of a coastal protected marine area, embedded between the inputs from Bagnoli steel plant to the south and a sewage plant, Volturno River and Regi Lagni channel to the north. The study integrated chemical-sedimentological data with biological and ecotoxicological analyses to assess anthropogenic pressures and natural variability. Data reveal marked differences in anthropogenic pollution between southeastern and northwestern zone, with the north affected by both inorganic and organic flows and the south influenced by levels of As, Pb and Zn in the sediments above law limits, deriving from inputs of the Bagnoli brownfield site. Meiobenthic data revealed at south higher relative abundance of sensitive species to pollution and environmental stress to the south, i.e. Lobatula lobatula and Rosalina bradyi, whereas to the north relative abundance of stress tolerant Quinqueloculina lata, Quinqueloculina pygmaea and Cribroelphidium cuvilleri were determined.
显示更多 [+] 显示较少 [-]Screening of short-lived climate pollutants in a street canyon in a mid-sized city in Brazil 全文
2016
Krecl, Patricia | Targino, Admir Créso | Wiese, Luiz | Ketzel, Matthias | de Paula Corrêa, Marcelo
Black carbon (BC) and tropospheric ozone (O3) are two main short-lived climate pollutants also linked to health effects. They are ubiquitous in street canyons, since this environment is a hotspot for traffic-related pollutants due to their particular airflow characteristics, location within the cities and the high density of vehicles and population.We report on BC and O3 concentrations measured in a Brazilian city in November 2014. Measurements of BC at 880 nm wavelength were conducted in a street canyon on the north and south façades and at rooftop level (7 wavelengths, including 880 nm) whereas O3 was recorded only on the south façade. Concurrent meteorological data were gathered at a suburban and a rooftop sites.Clear diurnal patterns were found for BC related to traffic emissions and atmospheric mixing conditions. Ozone peaked in the afternoon in response to maximum photochemical production and at night most likely linked to vertical and/or horizontal transport. By using conditional bivariate probability functions, we identified on-road traffic as the main local source for BC during daytime, and at night an intermittent signal was associated with local waste and biomass burned on the city's outskirts. A complementary air backward trajectory analysis helped conclude that locally produced O3 was enhanced by regional transport from large cities and/or biomass smoke.Mitigation strategies for BC and O3 depletion should target the vehicle fleet, particularly diesel buses, reduction of biomass and waste burning at local level, and decrease of open biomass burning in large areas in Brazil and neighbor countries.
显示更多 [+] 显示较少 [-]Spatial variations in annual cycles of body-size spectra of planktonic ciliates and their environmental drivers in marine ecosystems 全文
2016
Xu, Henglong | Jiang, Yong | Xu, Guangjian
Body-size spectra has proved to be a useful taxon-free resolution to summarize a community structure for bioassessment. The spatial variations in annual cycles of body-size spectra of planktonic ciliates and their environmental drivers were studied based on an annual dataset. Samples were biweekly collected at five stations in a bay of the Yellow Sea, northern China during a 1-year cycle. Based on a multivariate approach, the second-stage analysis, it was shown that the annual cycles of the body-size spectra were significantly different among five sampling stations. Correlation analysis demonstrated that the spatial variations in the body-size spectra were significantly related to changes of environmental conditions, especially dissolved nitrogen, alone or in combination with salinity and dissolve oxygen. Based on results, it is suggested that the nutrients may be the environmental drivers to shape the spatial variations in annual cycles of planktonic ciliates in terms of body-size spectra in marine ecosystems.
显示更多 [+] 显示较少 [-]Levels of genetic diversity and taxonomic status of Epinephelus species in United Arab Emirates fish markets 全文
2016
Ketchum, Remi N. | Dieng, Mame M. | Vaughan, Grace O. | Burt, John A. | Idaghdour, Youssef
Understanding the patterns of genetic diversity of fish species is essential for marine conservation and management. This is particularly important in the Arabian Gulf where marine life is subject to extreme environmental conditions that could impact genetic diversity. Here we assess genetic diversity of the most commercially important fish in the United Arab Emirates; groupers (Epinephelus spp.). Sequencing of 973bp mitochondrial DNA from 140 tissue samples collected in four main fish markets revealed 58 haplotypes clustered within three groups. Data analysis revealed the presence of three distinct Epinephelus species being marketed as one species (hammour): Epinephelus coioides, Epinephelus areolatus and Epinephelus bleekeri. We report species-specific genetic markers and demonstrate that all three species exhibit relatively low levels of genetic variation, reflecting the effect of overfishing and environmental pressures. In light of the genetic evidence presented here, conservation and management of groupers in the UAE warrant the implementation of species-specific measures.
显示更多 [+] 显示较少 [-]Chemical speciation of aerosols and air quality degradation during the festival of lights (Diwali) 全文
2016
Pervez, Shamsh | Chakrabarty, Rajan K. | Dewangan, Shippi | Watson, John G. | Chow, Judith C. | Matawle, Jeevan Lal
Ambient PM2.5 (particulate matter less than 2.5 μm) samples, collected in a 8-week wintertime sampling program in two residential sites of Bhilai, India during the Indian Diwali festival in November 2012, were chemically characterized for 38 chemical species including eight speciated carbonaceous fractions (SCFs) of elemental (EC) and organic carbon (OC), twenty one metallic elements, and nine water soluble ionic species. Our objectives were to investigate: 1) relative abundances of SCFs contained in PM2.5during the Diwali festival period compared to normal days, and 2) enrichment pattern of potential inorganic markers of firework emission in ambient PM2.5during the festival days. Eight-fold increase inPM2.5mass concentrations were measured during the Diwali festival days compared to concentrations occurring in normal days. Bursting of firecrackers in the residential streets have shown significant contribution to the emission markers (K, Mg, Zn, S, EC and OC) along with crustal markers (Ca, Fe, Al) in ambient PM2.5aerosol samples. Concentrations of water soluble ionic species were found to be 10 times greater than those found in normal days. Further, the anion/cation ratios were found to reach a factor of 2; indicating the acidic character of emissions resulting from fireworks. The relative abundance of SCFs and higher ratios of OC to EC during the Diwali episode suggested the significant formation of secondary organic carbon (SOC) aerosols. We estimate that aerosols emitted from firework bursting contribute up to 32% of total ambient PM2.5 during the Diwali festival.
显示更多 [+] 显示较少 [-]Distribution variation of heavy metals in maricultural sediments and their enrichment, ecological risk and possible source—A case study from Zhelin bay in Southern China 全文
2016
Wang, Yi | Wei, Yaning | Guo, Pengran | Pan, Jiachuan | Wu, Qihang | Liu, Ning
The study characterized the enrichment, ecological risk and possible source of heavy metals (As, Cd, Cr, Cu, Hg, Ni, Pb and Zn) in sediments from a typical mariculture bay. The concentrations of the metals were analyzed in sediments collected from Zhelin bay. The distribution variation was examined during the past decade, which had an increase tendency till 2011. The enrichment factor and geoaccumulation indices suggested Pb, As, Cu and Zn were minor enrichment and unpolluted to moderately polluted, and Ni at cage mariculture area was moderately-severe enrichment and strongly polluted. This area had medium to high ecological risk, especially at the northwest coastal area of semi-closed bay, with high-medium to high ecological risk. Correlation and principal component analyses indicated that most of heavy metals, especially for As, Pb and Ni, primarily resulted from the combustion of gasoline and diesel fuel and the ship protective layer.
显示更多 [+] 显示较少 [-]An assessment of Qatar's coral communities in a regional context 全文
2016
Burt, John A. | Smith, Edward G. | Warren, Christopher | Dupont, Jennifer
Qatar's once extensive coral communities have undergone considerable change in recent decades. We quantitatively surveyed three coral assemblages in Qatar to assess current status, and compared these against 14 sites in Bahrain and the United Arab Emirates to evaluate Qatar in a larger biogeographic context. Umm Al-Arshan had the highest species richness of 17 sites examined in the southern Arabian Gulf, as well as the highest coral cover and the only Acropora observed on sites in Qatar. Coral cover and richness were more modest at Fuwayrit and Al-Ashat, reflecting greater impacts from earlier stress events. Two distinct communities were identified across the southern Gulf, with Umm Al-Arshan clustering with high-cover, mixed merulinid/poritid assemblages that were less impacted by earlier bleaching and long-term stress, while Fuwayrit and Al-Ashat grouped with a lower-cover, stress-tolerant community characteristic of more extreme environments in the southern Gulf. We recommend implementation of a nation-wide baseline assessment of coral communities to guide development of an MPA network and long-term coral monitoring program for Qatar.
显示更多 [+] 显示较少 [-]Distribution, sources and ecological risk assessment of PAHs in surface sediments from the Luan River Estuary, China 全文
2016
Zhang, Daolai | Liu, Jinqing | Jiang, Xuejun | Cao, Ke | Yin, Ping | Zhang, Xunhua
The distribution, sources and risk assessment of 16 polycyclic aromatic hydrocarbons (PAHs) of surface sediments in the Luan River Estuary, China, have been investigated in the research. The results indicated that the total concentrations of 16 PAHs in surface sediments of the Luan River Estuary ranged from 5.1 to 545.1ngg−1dw with a mean value of 120.8ngg−1dw, which is relatively low in comparison with other estuaries around the world. The PAHs in the study area were mainly originated from pyrogenic sources. Besides, PAHs may be contaminated by petrogenic PAHs as indicated by the selected ratios of PAHs, the 2-tailed Pearson correlation analysis and principal components analysis at different sites. The result of the ecological risk assessment shows little negative effect for most individual PAHs in surface sediments of the Luan River Estuary, China.
显示更多 [+] 显示较少 [-]Mercury concentration in fine atmospheric particles during haze and non-haze days in Shanghai, China 全文
2016
Bo, Dandan | Cheng Jinping, | Xie, Haiyun | Zhao, Wenchang | Wei, Yuqing | Chen, Xiaojia
Concentrations of fine particulate mercury (PHg), particulate matter ≤2.5 μm (PM2.5), and particulate matter ≤10 μm (PM10) were monitored for the whole year of 2013 in Shanghai, China. The average concentrations of PHg were 1270 ± 716 pg/m3 and 341 ± 187 pg/m3 during haze and non-haze days respectively. The average PHg concentration throughout the whole year 2013 was 642 ± 616pg/m3. It was observed that PHg concentrations on haze days were 3 times higher than on non-haze days. The concentration of PHg on non-haze days in 2013 varied from 0.25 to 0.48 ng/m3. The mean monthly PHg concentration was highest in December (1.92 ng/m3), while the minimum mean concentration was observed in February and August (0.80 ng/m3), and there was a clear seasonal variation: winter (1.67 ng/m3), autumn (1.08 ng/m3), spring (1.02 ng/m3), and summer (1.00 ng/m3) during haze days. The correlation between PHg and PM2.5 was strong (r = 0.96 on haze days; r = 0.90 on non-haze days), while the correlation between PHg and PM10 was weaker (r = 0.85 on haze days; r = 0.57 on non-haze days). The PHg concentration on haze days was always higher than on non-haze days, indicating that haze conditions were accelerating the formation of PHg. The result also indicated that PHg was inclined to combine with fine particles. The existence of strong correlations between the concentrations of PM2.5, PM10, and PHg indicated the commonality of the contributing sources, such as traffic, industrial emissions, and the combustion of coal.
显示更多 [+] 显示较少 [-]SPECIEUROPE: The European data base for PM source profiles 全文
2016
Pernigotti, Denise | Belis, Claudio A. | Spanò, Luca
A new database of atmospheric particulate matter emission source profiles in Europe (SPECIEUROPE) developed in the framework of the Forum for air quality modeling in Europe (FAIRMODE, Working Group 3) is accessible at the website http://source-apportionment.jrc.ec.europa.eu/Specieurope/index.aspx. It contains the chemical composition of particulate matter emission sources reported in the scientific literature and reports drafted by competent authorities. The first release of SPECIEUROPE consists of 151 measured (original), 13 composite (merging different subcategories of similar sources), 6 calculated (from stoichiometric composition) and 39 derived (results of source apportionment studies) profiles. Each profile is related to one or more source categories or subcategories. The sources with the highest PM relative mass toxic pollutants such as PAHs are fuel oil burning, ship emissions, coke burning and wood burning. Heavy metals are most abundant in metal processing activities while halogens are mostly present in fertilizer production, coal burning and metallurgic sector. Anhydrosugars are only measured in biomass and wood burning source categories, because are markers for these categories. The alkaline earth metals are mostly present in road dust, cement production, soil dust and sometimes coal burning. Source categories like traffic and industrial, which contain heterogeneous subcategories, show the greatest internal variability.The relationships between sources profiles were also explored using a cluster analysis approach based upon the Standardized Identity Distance (SID) indicator. The majority of profiles are allocated in 8 major clusters. Some of the clusters include profiles mainly from one source category (e.g. wood burning) while others, such as industrial source profiles, are more heterogeneous and spread over three different clusters.
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