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Factors regulating the distribution of O3 and NOx at two mountainous sites in Seoul, Korea
2016
Nguyen, Hang Thi | Kwon, Eilhann E. | Kim, Ki Hyun | Pandey, Sudhir Kumar | Chambers, Scott | Kumar, Pawan | Kang, Ch'ang-hŭi | Cho, Seog-Ju | Oh, Jong-Min | Brown, Richard J.C.
The concentrations of ozone (O3) and nitrogen oxides (NOx) were measured at two mountainous sites in Buk-Han (BH) and Gwan-Ak (GA) and at a reference site in Gwang-Jin (GJ), all in Seoul, South Korea, over a four-year period (2010–2013). The mean concentration (ppb) of NOx was comparable at the mountainous sites (22.9 ± 20.7 (BH) and 20.9 ± 16.9 (GA)) but about half the concentration at the reference site in GJ (47.8 ± 36.4). In contrast, the mean value (ppb) for O3 at the three sites exhibited a reversed pattern such as 40.2 ± 19.7 at GA, 28.6 ± 15.4 at BH, and 21.8 ± 18.3 at GJ. The concentration of NOx was higher in winter/fall relative to summer/spring at all three sites. Like the clear distinctions observed from the spatial distribution patterns, the seasonal trends conrasted sharply between NOx and O3. Results of a correlation analysis suggested that the distribution of O3 was significantly affected by meteorological parameters (e.g., TEMP, UV, and solar radiation). According to a back trajectory analysis, the highest O3 levels at both mountainous sites were caused by air masses passing over marine areas, while the effects of ozone precursors on ozone concentration were attributed to air masses originating from China and/or the mainland (S. Korea).
显示更多 [+] 显示较少 [-]Difference analysis of the relationship between household per capita income, per capita expenditure and per capita CO2 emissions in China: 1997–2014
2016
Dong, Yiman | Zhao, Tao
Driven by the buoyancy of economy and continuous improvement of people's living standards, residential sector has gradually become the second largest CO2 emissions source in China. Reducing the fast rising rate of CO2 emissions in this sector is essential for realizing the target of carbon emission mitigation in China. The researches on the driving factors of residential CO2 emissions have attracted scholars' attention recently, yet few studies can interpret the causality relationship between household per capita income-expenditure-CO2 emissions at national and regional levels. Based on econometric techniques and a panel data set, this paper presents an investigation of the causality relationship, which combines household per capita income, per capita expenditure and per capita CO2 emissions (hereafter referred to as PI, PE, and CE, respectively) on a national level and within three regions (namely, eastern, central, and western regions of China) from 1997 to 2014. Urban and rural areas are considered as well. The empirical results manifest a varied causality relationship in different regions. For example, PI and PE correspond to CE in eastern rural area, but this phenomenon does not occur in central rural area. In addition, urban and rural differences are displayed. There is no causality between PI and PE in western urban area, while a bidirectional causal relationship emerges in PI and PE for western rural area. Finally, this study proposes some policy implications to decrease the increase rate of household CO2 emissions in China.
显示更多 [+] 显示较少 [-]Variation in the composition of corals, fishes, sponges, echinoderms, ascidians, molluscs, foraminifera and macroalgae across a pronounced in-to-offshore environmental gradient in the Jakarta Bay–Thousand Islands coral reef complex
2016
Cleary, D.F.R. | Polónia, A.R.M. | Renema, W. | Hoeksema, B.W. | Rachello-Dolmen, P.G. | Moolenbeek, R.G. | Budiyanto, A. | Yahmantoro, | Tuti, Y. | Giyanto, | Draisma, S.G.A. | Prud'homme van Reine, W.F. | Hariyanto, R. | Gittenberger, A. | Rikoh, M.S. | de Voogd, N.J.
Substrate cover, water quality parameters and assemblages of corals, fishes, sponges, echinoderms, ascidians, molluscs, benthic foraminifera and macroalgae were sampled across a pronounced environmental gradient in the Jakarta Bay–Thousand Islands reef complex. Inshore sites mainly consisted of sand, rubble and turf algae with elevated temperature, dissolved oxygen, pH and chlorophyll concentrations and depauperate assemblages of all taxa. Live coral cover was very low inshore and mainly consisted of sparse massive coral heads and a few encrusting species. Faunal assemblages were more speciose and compositionally distinct mid- and offshore compared to inshore. There were, however, small-scale differences among taxa. Certain midshore sites, for example, housed assemblages resembling those typical of the inshore environment but this differed depending on the taxon. Substrate, water quality and spatial variables together explained from 31% (molluscs) to 72% (foraminifera) of the variation in composition. In general, satellite-derived parameters outperformed locally measured parameters.
显示更多 [+] 显示较少 [-]Dry bulk cargo shipping — An overlooked threat to the marine environment?
2016
Grote, Matthias | Mazurek, Nicole | Gräbsch, Carolin | Zeilinger, Jana | Le Floch, Stéphane | Wahrendorf, Dierk-Steffen | Höfer, Thomas
Approximately 9.5billiontonnes of goods is transported over the world oceans annually with dry bulk representing the largest cargo group. This paper aims to analyse whether the transport and associated inputs of dry bulks into the sea create a risk for the marine environment. For this purpose, we analyse the international regulatory background concerning environmental protection (MARPOL), estimate quantities and identify inputs of such cargoes into the oceans (accidental and operational), and use available information for hazard assessment. Annually, more than 2.15milliontonnes of dry bulk cargoes are likely to enter the oceans, of which 100,000tonnes are potentially harmful to the marine environment according to the definition included in draft maritime regulation. The assessment of the threat to the marine environment is hampered by a lack of available information on chemical composition, bioavailability and toxicity. Perspectives for amendments of the unsatisfying pollution prevention regulations are discussed.
显示更多 [+] 显示较少 [-]Estimation of mercury background values in sediment and biota of the Bijagós archipelago, Guinea-Bissau
2016
Coelho, J.P. | Monteiro, R.J.R. | Catry, T. | Lourenço, P.M. | Catry, P. | Regalla, A. | Catry, I. | Figueira, P. | Pereira, E. | Vale, C. | P.Granadeiro, José
This work evaluates the mercury (Hg) contamination status (sediments and biota) of the Bijagós archipelago, off the coast of Guinea-Bissau. Sediments exhibited very low concentrations (<1–12ngg−1), pointing to negligible sources of anthropogenic Hg in the region. Nevertheless, Hg is well correlated to the fine fraction, aluminium, and loss on ignition, indicating the effect of grain size and organic matter content on the presence of Hg in sediments. Mercury in the bivalves Tagelus adansoni and Senilia senilis did not vary considerably among sites, ranging within narrow intervals (0.09–0.12 and 0.12–0.14μgg−1 (dry weight), respectively). Divergent substrate preferences/feeding tactics may justify slight differences between species. The value 11ngg−1 is proposed as the sediment background concentration for this West-African coastal region, and concentrations within the interval 8–10ngg−1 (wet weight) may be considered as reference range for S. senilis and T. adansoni in future monitoring studies.
显示更多 [+] 显示较少 [-]Linkage between speciation of Cd in mangrove sediment and its bioaccumulation in total soft tissue of oyster from the west coast of India
2016
Chakraborty, Parthasarathi | Ramteke, Darwin | Gadi, Subhadra Devi | Bardhan, Pratirupa
This study established a mechanistic linkage between Cd speciation and bioavailability in mangrove system from the west coast of India. High bioaccumulation of Cd was found in the oyster (Crassostrea sp.) even at low Cd loading in the bottom sediment. Bioaccumulation of Cd in the oyster gradually increased with the increasing concentrations of water soluble, exchangeable and carbonate/bicarbonate forms of Cd in the sediments. Fe/Mn oxyhydroxide phase was found to control Cd bioavailability in the sediment system. Cd-associated with sedimentary organic matter was bioavailable and organic ligands in the sediments were poor chelating agents for Cd. This study suggests that bioaccumulation of Cd in oyster (Crassostrea sp.) depends not on the total Cd concentration but on the speciation of Cd in the system.
显示更多 [+] 显示较少 [-]Circadian rhythm of a red-tide dinoflagellate Peridinium quadridentatum in the port of Veracruz, Gulf of Mexico, its thecal morphology, nomenclature and geographical distribution
2016
Okolodkov, Yuri B. | Campos-Bautista, Guadalupe | Gárate Lizárraga, Ismael
A circadian rhythm of the dinoflagellate Peridinium quadridentatum was studied at a time-series station in the southwestern Gulf of Mexico, in May 2007. Different substrates (water column, the seagrass Thalassia testudinum, macroalgae, coral rubble and sandy sediment surface) were sampled at the site at 1.5–3.5m depth. In the samples of coral rubble, P. quadridentatum was scarce. In the water column, the species showed an abundance peak at 15:00. The cell abundance of P. quadridentatum in Thalassia samples increased from 15:00 until 18:00 (1.81×104cells/gsubstratewet weight), and then continuously decreased until 06:00. Changes in P. quadridentatum cell abundance on macroalgae followed the same trend as on Thalassia, with the maximal value at 18:00. The higher abundance of P. quadridentatum (up to 1.40×104cells/gSWW) in macroalgae samples showed the preference for seaweeds. P. quadridentatum has a neritic tropical–boreal distribution. A new combination is proposed: Peridinium quadridentatum var. trispiniferum.
显示更多 [+] 显示较少 [-]Assessment of heavy metal contamination in surface sediments of the west Guangdong coastal region, China
2016
Zhao, Guangming | Lu, Qingyuan | Ye, Siyuan | Yuan, Hongming | Ding, Xigui | Wang, Jin
Heavy metals (As, Cd, Cr, Cu, Hg, Pb, Zn), organic carbon and grain size of 237 surface sediment samples and one sediment core, taken from the west Guangdong coastal region in January 2008, were analyzed to evaluate the spatial distribution and pollution status. Results show that the ranges of the measured heavy metal concentrations in sediments are as follows: 8.33–39.49mg/kg for As, 0.1–1.49mg/kg for Cd, 33–108mg/kg for Cr, 11.5–78.8mg/kg for Cu, 0.04–0.26mg/kg for Hg, 21–73mg/kg for Pb, 56–248mg/kg for Zn. The heavy metal enrichment is closely associated with Corg and grain size. Both the metal enrichment factor and geoaccumulation index indicate that there was no detected pollution on metals As, Cr, Cu, Pb in our study area and a slight to moderate contamination of Cd, Hg and Zn. However, As, Cr and Cu have showed a certain risk.
显示更多 [+] 显示较少 [-]Effect and mechanism of a High Gradient Magnetic Separation (HGMS) and Ultraviolet (UV) composite process on the inactivation of microbes in ballast water
2016
Ren, Zhijun | Zhang, Lin | Shi, Yue | Leng, Xiaodong | Shao, Jingchao
The patented technology of a High Gradient Magnetic Separation (HGMS)-Ultraviolet (UV) composite process was used to treat ballast water. Staphylococcus aureus (S. aureus) was selected as the reference bacteria. After treatment by the HGMS-UV process, the concentration of S. aureus on the log 10 scale was lower than 2 at different flow rates, S. aureus suffered the most serious damage, and K+ leakage of the bacteria was 1.73mg/L higher than separate 60min UV irradiation (1.17mg/L) and HGMS (0.12mg/L) processes. These results demonstrated that the HGMS-UV composite process was an effective approach to treat ballast water. Further, the HGMS process had synergistic action on the subsequent UV irradiation process and accelerated cell membrane damage. Meanwhile, the results of superoxide dismutase (SOD) activities of bacteria and DNA band analyses indicated that the inactivation mechanisms were different for HGMS and UV irradiation.
显示更多 [+] 显示较少 [-]Phosphorus as a driver of nitrogen limitation and sustained eutrophic conditions in Bolinao and Anda, Philippines, a mariculture-impacted tropical coastal area
2016
Ferrera, Charissa M. | Watanabe, Atsushi | Miyajima, Toshihiro | San Diego-McGlone, Maria Lourdes | Morimoto, Naoko | Umezawa, Yu | Herrera, Eugene | Tsuchiya, Takumi | Yoshikai, Masaya | Nadaoka, Kazuo
The dynamics of nitrogen (N) and phosphorus (P) was studied in mariculture areas around Bolinao and Anda, Philippines to examine its possible link to recurring algal blooms, hypoxia and fish kills. They occur despite regulation on number of fish farm structures in Bolinao to improve water quality after 2002, following a massive fish kill in the area. Based on spatiotemporal surveys, coastal waters remained eutrophic a decade after imposing regulation, primarily due to decomposition of uneaten and undigested feeds, and fish excretions. Relative to Redfield ratio (16), these materials are enriched in P, resulting in low N/P ratios (~6.6) of regenerated nutrients. Dissolved inorganic P (DIP) in the water reached 4μM during the dry season, likely exacerbated by increase in fish farm structures in Anda. DIP enrichment created an N-limited condition that is highly susceptible to sporadic algal blooms whenever N is supplied from freshwater during the wet season.
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