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Characteristics and contributions of biogenic secondary organic aerosol tracers to PM2.5 in Shanghai, China
2017
Zhu, Wenfei | Luo, Lina | Cheng, Zhen | Yan, Naiqiang | Lou, Shengrong | Ma, Yongpeng
To evaluate biogenic secondary organic aerosol (BSOA) tracers from biogenic precursors, fine particles (PM2.5) were collected using filter-based high-volume samplers from spring-summer of 2015 in the central part of Shanghai, China. The results showed that the isoprene SOA tracers exhibited the highest levels (17.64 ± 9.75 ng m−3) and were always observed along with higher temperatures, which results in a higher tracer formation rate and isoprene emission strength. However, the isoprene SOA tracers showed a weak correlation with the relative humidity (p > 0.05). The isoprene SOA tracers showed remarkable correlations with the [H+] because of the enhanced formation of isoprene SOA in the acidic aerosols. On the basis of these results, 2-methylglyceric acid was determined to have weak correlations with other isoprene tracers, which indicated that it had different formation pathways from those of other isoprene SOA tracers. Cis-pinonic acid had negative correlations with other SOA tracers, indicating that it is the first product in the oxidation process. Furthermore, the isoprene-based tracers (SOCisoprene) were calculated to be 0.031–0.299 μg C m−3 (with an average of 0.114 ± 0.062 μg C m−3), which accounted for more than half of the biogenic SOA. The SOC estimation with SOA tracers (SOC tracer-based) averaged 0.155 ± 0.066 μg m−3, with a range from 0.049 to 0.309 μg m−3 during the sampling period, which amounted to 2.73% OC.
Afficher plus [+] Moins [-]Temporal trends in live foraminiferal assemblages near a pollution outfall on the Levant shelf
2017
Tadir, Roni | Benjamini, Chaim | Almogi-Labin, Ahuva | Hyams-Kaphzan, Orit
Long and short term effects of activated sewage sludge input on live benthic foraminiferal assemblages of the shallow shelf off Palmachim, Israel were examined at three stations along the eutrophic gradient. Over ten years from 2003 to 2012, foraminiferal abundance decreased dramatically by >50% in all stations. In 2012, new species were found near the discharge point, relative abundance of the dominant species decreased and in-sediment depth increased. In the remote stations the dominant species failed to bloom seasonally. Each year, dispersion of sludge was accompanied by intense current activity, aeration, and periodic local sediment transport, reintroducing species from nearby. Storm frequency was notably high in 2012. The decrease in numbers over time despite seasonal amelioration indicates that the constant OM input is a permanent source of environmental stress. Aside from this stress, natural variability, changes in Nile input, or a hidden impact of long-term climate change may play a role.
Afficher plus [+] Moins [-]Trichodesmium blooms and warm-core ocean surface features in the Arabian Sea and the Bay of Bengal
2017
Jyothibabu, R. | Karnan, C. | Jagadeesan, L. | Arunpandi, N. | Pandiarajan, R.S. | Muraleedharan, K.R. | Balachandran, K.K.
Trichodesmium is a bloom-forming, diazotrophic, non-heterocystous cyanobacteria widely distributed in the warmer oceans, and their bloom is considered a ‘biological indication’ of stratification and nitrogen limitation in the ocean surface layer. In the first part of this paper, based on the retrospective analyses of the ocean surface mesoscale features associated with 59 Trichodesmium bloom incidences recorded in the past, 32 from the Arabian Sea and the Bay of Bengal, and 27 from the rest of the world, we have showed that warm-core features have an inducing effect on bloom formation. In the second part, we have considered the environmental preferences of Trichodesmium bloom based on laboratory and field studies across the globe, and proposed a view about how warm-core features could provide an inducing pre-requisite condition for the bloom formation in the Arabian Sea and the Bay of Bengal. Proposed that the subsurface waters of warm-core features maintain more likely chances for the conducive nutrient and light conditions required for the triggering of the blooms.
Afficher plus [+] Moins [-]Microplastics in gut contents of coastal freshwater fish from Río de la Plata estuary
2017
Pazos, Rocío S. | Maiztegui, Tomás | Colautti, Darío C. | Paracampo, Ariel H. | Gómez, Nora
The presence of microplastics (MPs) in gut contents of coastal freshwater fish of the Rio de la Plata estuary was studied. Samples were taken in six sites where 87 fish belonging to 11 species and four feeding habits were captured. Presence of MPs was verified in the 100% of fish. The fibres represented the 96% of MPs found. The number of MPs in gut contents was significantly higher close to sewage discharge. There was not found relationship between number of MPs and fish length, weight or feeding habit. The spatial differences in mean number of MPs in fish observed in this study, suggest that environmental availability of MPs could be of great importance to explain the differences found among sampling sites analysed. This work represents the first study about the interaction between MPs and aquatic organisms in this important estuarine ecosystem of South America.
Afficher plus [+] Moins [-]Continuous monitoring of noise levels in the Gulf of Catania (Ionian Sea). Study of correlation with ship traffic
2017
Viola, S. | Grammauta, R. | Sciacca, V. | Bellia, G. | Beranzoli, L. | Buscaino, G. | Caruso, Fabbio | Chierici, F. | Cuttone, G. | D’Amico, A. | De Luca, V. | Embriaco, D. | Favali, P. | Giovanetti, G. | Marinaro, G. | Mazzola, S. | Filiciotto, F. | Pavan, G. | Pellegrino, C. | Pulvirenti, S. | Simeone, F. | Speziale, F. | Riccobene, G.
Acoustic noise levels were measured in the Gulf of Catania (Ionian Sea) from July 2012 to May 2013 by a low frequency (<1000Hz) hydrophone, installed on board the NEMO-SN1 multidisciplinary observatory. NEMO-SN1 is a cabled node of EMSO-ERIC, which was deployed at a water depth of 2100m, 25km off Catania. The study area is characterized by the proximity of mid-size harbors and shipping lanes. Measured noise levels were correlated with the passage of ships tracked with a dedicated AIS antenna. Noise power was measured in the frequency range between 10Hz and 1000Hz. Experimental data were compared with the results of a fast numerical model based on AIS data to evaluate the contribution of shipping noise in six consecutive 1/3 octave frequency bands, including the 1/3 octave frequency bands centered at 63Hz and 125Hz, indicated by the Marine Strategy Framework Directive (2008/56/EC).
Afficher plus [+] Moins [-]In situ biomonitoring of air quality in rural and urban environments of Mexico Valley through genotoxicity evaluated in wild plants
2017
Gómez-Arroyo, Sandra | Cortés-Eslava, Josefina | Loza-Gómez, Paola | Arenas-Huertero, Francisco | de la Mora, Michel Grutter | Morton Bermea, Ofelia
Air pollution is one the main causes of DNA damage in living organisms. Continuous exposure to the complex mixture of gases of polluted atmospheres affects health in many ways. Sentinel organisms are good biological models to assess the genotoxic damage caused by various chemicals such as atmospheric pollutants.In this study the plant species Taraxacum officinale and Robinsonecio gerberifolius were exposed during 2015, in the dry and rainy seasons, for 0, 2, 4 and 6 weeks to two different atmospheres of Mexico Valley, one rural in Altzomoni atmospheric observatory (ALTZ) and other urban in the atmospheric observatory of Centro de Ciencias de la Atmósfera (CCA), located in Universidad Nacional Autónoma de México (UNAM).Leaves of exposed plants were processed to analyze genotoxic damage by single-cell gel electrophoresis. To found any relation, the presence of pollutants in the atmosphere of both sites was analyzed with a Cavity Ring-Down Spectrometer (CRDS) and in the leaves the presence of heavy metals with an inductively coupled plasma mass spectrometer.Single-cell gel electrophoresis results showed higher damage in the leaves exposed to higher pollution in the UNAM atmospheric station in comparison to the ALTZ and controls, which was maintained in growth chambers under controlled conditions. Significant differences between rainy and dry seasons were found. Chemical analysis showed a significant increase in various heavy metals, especially in rainy season in both exposure sites. Increased DNA damage observed in both plant species at CCA station could be caused by accumulation trough six weeks.
Afficher plus [+] Moins [-]Use of multiple functional traits of protozoa for bioassessment of marine pollution
2017
Zhong, Xiaoxiao | Xu, Guangjian | Xu, Henglong
Ecological parameters based on multiply functional traits have many advantages for monitoring programs by reducing “signal to noise” ratios of observed species data. To identify potential indicators for bioassessment of marine pollution in function space, the functional patterns of protozoan communities and relationships with environmental changes were studied in coastal waters of the Yellow Sea during a 1-year period. The results showed that: (1) the spatial variability in functional trait distributions of the protozoa was significantly associated with changes in environmental variables, especially chemical oxygen demand (COD) and nutrients on spatial scale; (2) the functional traits, especially food resources and feeding type, were significantly correlated with COD and nutrients; and (3) the functional diversity indices were generally related to nutrients or COD. Based on the results, we suggest that the functional traits and diversity indices of protozoan communities may be used as more effective indicators for bioassessment of marine pollution.
Afficher plus [+] Moins [-]Unsustainable human-induced injuries to the Critically Endangered Taiwanese humpback dolphins (Sousa chinensis taiwanensis)
2017
Wang, John Y. | Riehl, Kimberly N. | Yang, Shih-Chu | Araújo-Wang, Claryana
The Critically Endangered Taiwanese humpback dolphin (Sousa chinensis taiwanensis) is endemic to inshore and estuarine waters of central western Taiwan. It numbers fewer than 75 individuals, is declining and faces a myriad of human threats. Data from a long-term photo-identification program on these dolphins allowed major injuries to be examined quantitatively. A large proportion (57.7%) of individuals had suffered major human-induced injuries that likely compromised their health, survivorship or reproductive potential and thus, the future of this subspecies. Considering major injuries as “takes”, the injury rate (1.13 dolphins/year) for the population was 8–8.5 times higher than its Potential Biological Removal rate. Observations of new injuries and fishing gear entanglements on several dolphins showed that fisheries continue to be the predominant cause of these major injuries. Unless immediate action is taken to reduce harmful fisheries, extinction is imminent for Taiwan's only endemic dolphin.
Afficher plus [+] Moins [-]Spatial variation of microbial communities in sediments along the environmental gradients from Xiaoqing River to Laizhou Bay
2017
Yu, Shu-Xian | Pang, Yun-Long | Wang, Yinju | Li, Jia-Lin | Qin, Song
The Laizhou Bay is famous for aquaculture, but has been subject to eutrophication and contamination for years. High concentrations of nutrients from the Xiaoqing River are considered as the main cause for significant eutrophication in the west of Laizhou Bay. Here we present results of the research on sedimentary microbial assemblages along this spatial gradient between riverine and marine environments by high-throughput sequencing. The predominant phyla/classes of bacteria and fungi clustered the samples into two distinct provinces, while discriminant taxa of each province were strongly associated with spatial factors and inorganic nitrogen. Spatial variation of bacterial communities was mainly related with the distribution of phosphates, suggesting a phosphate-limitation pattern for the bacterial communities. Alpha- and beta-diversity of fungal communities exhibited a significant correlation with water depth. We consider the distinct distributional gradients of bacterial and fungal communities partly explain the different roles in the biogeochemical processes of coastal sediment.
Afficher plus [+] Moins [-]Evaluation of metal contamination in the Mand River delta, Persian Gulf
2017
Pourkerman, Majid | Amjadi, Sedigheh | Beni, Abdolmajid Naderi | Lahijani, Hamid | Mehdinia, Ali
Mand River is one of four permanent rivers flowing into the Persian Gulf. Intense industrial activities have significantly impacted its watershed and estuary. In order to evaluate metal contamination and their provenance nine sediment samples were taken from the Mand Delta. Enrichment factors were employed to detect anthropogenic contributions to levels of metal pollution. We also calculated weathering indices in order to identify the source of the metals, related to geological units. Pollution levels were assessed using the modified degree of contamination. Geological units, oil combustion, aerosols and industrial activities are the main factors controlling the abundance of Cr, As, Ni and Pb. Wave action, coastal currents, grain-size parameters, mineralogy, bio-accommodation and organic matter are the factors affecting the distribution and concentration of metals in the study area. More studies are needed to evaluate the impact of metal pollution on the fisheries industry and public health.
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