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A ten–year source apportionment study of ambient fine particulate matter in San Jose, California
2013
Wang, Yungang | Hopke, Philip K.
Fine particulate matter (PM2.5) composition data from the Speciation Trends Network (STN) site in San Jose, CA, were analyzed by positive matrix factorization (PMF) using U.S. Environmental Protection Agency (EPA) PMF version 5.0. These data were 24–h average mass concentrations and compositions obtained from samples taken every third day from October 2002 to February 2012. The eight identified sources include secondary sulfate, secondary nitrate, fresh sea salt, aged sea salt, diesel emission, road salt, gasoline vehicles, and wood combustion. The contributions to PM2.5 of these eight sources were 13.1%, 20.0%, 5.5%, 7.8%, 9.4%, 5.1%, 14.8, and 24.3%, respectively. The Ni–related industrial source, which was detected in previous PMF analysis, was not identified in our study and a sharp decrease in Ni concentrations was observed after the end of 2004. The contribution of road dust source decreased significantly after 2004 (Mann–Whitney test, p<0.01), which is probably the result of the city wide enhanced street sweeping programs starting in 2005. A 40% reduction in the wood combustion PM2.5 contribution between winter 2008 and winter 2009 was found. This decrease could be attributed to the San Francisco Bay Area Air Quality Management District (BAAQMD) wood burning rule implemented in July 2008. In the future, the effectiveness and benefits of the wood burning rule could be evaluated using the multi–wavelength aethalometer delta–c method.
显示更多 [+] 显示较少 [-]Photosynthetically active radiation loss in the atmosphere in North China
2013
Bai, Jianhui
Based on an understanding of energy, empirical formulas of hourly PAR (photosynthetically active radiation) under all sky conditions in North China were introduced and applied. An interesting and important phenomenon of the absorption of “water vapor factor” in 400–700 nm was studied and its real mechanism can be explained by the energy consumption of the substances (gas, liquid, solid–phase) through OH radicals during chemical and photochemical reactions. The PAR at the top of the atmosphere was estimated with good agreement. PAR losses in the atmosphere associated with “photochemical factor” and other materials in North China are spatial and seasonal dependence; their “annual” averages were 15.33 and 309.30 W m–2 in North China, respectively. The energy loss related to the “photochemical factor” should be considered in all kinds of basic processes in the atmosphere and model studies, including radiation transmission, photochemistry, air motion, and climate.
显示更多 [+] 显示较少 [-]Impacts of marine debris on wild animals in the coastal area of Korea
2013
Hong, Sunwook | Lee, Jongmyoung | Jang, Yong Chang | Kim, Yŏng-jun | Kim, Hee Jong | Han, Donguk | Hong, Sang Hee | Kang, Daeseok | Shim, Won Joon
Over the last decade, marine debris has become a major factor affecting the coastal ecosystem of Korea. This study compiled information regarding how marine debris impacts wildlife in Korea. Cases of marine debris impacting wildlife were collected from experts of various fields and from local participants through an open access website from February 2010 to March 2012. A total of 21 species were affected by marine debris: 18 species of birds, 2 species of mammals, and 1 species of crustacean. Five threatened or protected species were identified: black-faced spoonbill, finless porpoise, water deer, whooper swan, and greater painted snipe. Recreational fishing gears were the types of debris that most frequently impacted wildlife, especially birds. Black tailed gulls were the most vulnerable species to recreational fishing hooks and lines. Although it was preliminary, this study revealed that recreational fishing activities should be prioritized when managing marine debris in Korea.
显示更多 [+] 显示较少 [-]An integrative method for the evaluation, monitoring, and comparison of seagrass habitat structure
2013
Irving, Andrew D. | Tanner, Jason E. | Gaylard, Sam G.
Assessing environmental condition is essential for the management of coasts and their resources, but better management decisions occur when large databases are simplified into more manageable units of information. Here we present the habitat structure index (HSI), which enables rapid assessment and direct comparison of seagrass habitat structure using scores of 0 (poor) to 100 (excellent) based on integrating five habitat variables: area, continuity, proximity, percentage cover, and species identity. Acquiring data to calculate the HSI can be done in situ or from video recordings, and requires relatively simple methodology of belt transects, estimating percentage cover, and basic taxonomy. Spatiotemporal comparisons can usefully identify locations and periods of seagrass habitat change, potentially providing an early warning indicator of habitat damage and decline in environmental quality. Overall, the integrative approach of the HSI represents a step toward simplifying the exchange of environmental information among researchers, coastal managers, and governing bodies.
显示更多 [+] 显示较少 [-]Enhancement of the diesel oil degradation ability of a marine bacterial strain by immobilization on a novel compound carrier material
2013
Hou, Dengyong | Shen, Xianrong | Luo, Qun | He, Ying | Wang, Qingrong | Liu, Qiong
A novel floatable and biodegradable carrier material was made by coating puffed foxtail millet (PFM) with a calcium alginate (CA)-chitosan compound membrane. A diesel oil-degrading marine bacterial strain, Acinetobacter sp. F9, was immobilized on the carrier material. The number of viable F9 cells immobilized on the carrier material reached approximately 5×109CFU/g. This formulation could be stored at −20°C and 4°C for 10weeks without a significant decrease in the number of viable immobilized cells. SEM results showed that the coating membrane was porous and that F9 cells were immobilized on the walls of the pores. The immobilized F9 cells were able to remove more than 90% of the diesel oil by the second day, while free F9 cells did not remove 90% of the diesel oil until the seventh day. GC–MS analysis indicated that the immobilized F9 cells could remove diesel oil more completely than free cells. The immobilization of the F9 cells enhanced their ability to biodegrade diesel oil.
显示更多 [+] 显示较少 [-]Desorption kinetics of hydrophobic organic contaminants from marine plastic pellets
2013
Endo, Satoshi | Yuyama, Masaki | Takada, Hideshige
This study investigated the desorption behavior of polychlorinated biphenyls (PCBs) from marine plastic pellets. Long-term desorption experiments were conducted using field-collected polyethylene (PE) pellets. The results indicate that the desorption kinetics highly depends on the PE-water partition coefficients of PCB congeners. After 128d of the experiment, the smallest congener considered (CB 8) had desorbed nearly completely (98%), whereas major fractions (90–99%) of highly chlorinated congeners remained in the pellets. An intraparticle diffusion model mostly failed to reproduce the desorption kinetics, whereas an aqueous boundary layer (ABL) diffusion model well approximated the data. The desorption half-lives are estimated to 14d to 210years for CB 8 to CB 209 in an actively stirred solution (ABL thickness: 30μm). Addition of methanol to water enhanced the desorption to a large extent. A need for further work to explore roles of organic matter in facilitating solute transfer is suggested.
显示更多 [+] 显示较少 [-]The effect of urban sewage on benthic macrofauna: A multiple spatial scale approach
2013
Souza, F.M. | Brauko, K.M. | Lana, P.C. | Muniz, P. | Camargo, M.G.
We investigated the spatial scales of variation of macrofauna in intertidal flats subjected to different levels of contamination from urban effluents in two areas sampled in the Paranaguá Estuarine Complex. The scales considered were: Conditions; Tidal flats and Plots. Although the numerically dominant taxa showed the greatest variability at a scale of Tidal flats, the variability at the Condition scale was also significant. Tubificinae sp. 1, Laeonereis culveri and Heteromastus sp. were the most abundant organisms in the Contaminated area, while Heleobia australis was most abundant in the Non-contaminated area. Our results, contrary to those frequently observed in the literature, showed that the variability was significant at the scale of hundreds of metres (Tidal flats). At this scale, the intrinsic characteristics of each tidal flat are more important in determining macrofaunal distribution, while the effects of the urban sewage contamination represent the primary forces acting at a greater spatial scale.
显示更多 [+] 显示较少 [-]Silicon alleviates cadmium toxicity in Avicennia marina (Forsk.) Vierh. seedlings in relation to root anatomy and radial oxygen loss
2013
Zhang, Qiong | Yan, Chongling | Liu, Jingchun | Lu, Haoliang | Wang, Wenyun | Du, Jingna | Duan, Hanhui
The effects of Si on growth, the anatomy of the roots, radial oxygen loss (ROL) and Fe/Mn plaque on the root surface were investigated in Avicennia marina (Forsk.) Vierh. seedlings under Cd stress. Si prompted the growth of seedlings and reduced the Cd concentration in the root, stem and leaf of A. marina. Si prompted the development of the apoplastic barrier in the roots, which may be related to the reduction of Cd uptake. The higher amount of ROL and Mn plaque on the root surface due to Si were also related to the promotion of Cd tolerance in A. marina seedlings. Therefore, it is concluded that the alteration of the anatomy of the roots, the increase of ROL and Mn plaque of A. marina seedlings play an important role in alleviation of Cd toxicity due to Si.
显示更多 [+] 显示较少 [-]Influence of waste management policy on the characteristics of beach litter in Kaohsiung, Taiwan
2013
Liu, Dagang | Wang, Meng-Wei | Chen, Ping
Marine debris is a ubiquitous problem that poses a serious threat to the global oceans; it has motivated public participation in clean-up campaigns, as well as governmental involvement in developing mitigation strategies. While it is known that the problem of marine litter may be affected by waste management practices on land, beach survey results have seldom been compared with them. In this study, marine litter surveys on four beaches of Cijin Island were conducted to explore the effects of waste management and policy implications. Indirect evidence shows that chances for land-based litter, such as plastic bags and bottles, entering the marine environment can be greatly decreased if they can be properly reduced, reused and recycled. We suggest that mitigation measures should focus on source reduction, waste recycling and management, utilizing effective economic instruments, and pursuing a long-term public education campaign to raise the public awareness of this problem.
显示更多 [+] 显示较少 [-]Contaminants in magnificent frigatebird eggs from Barbuda, West Indies
2013
Trefry, Sarah A. | Diamond, Antony W. | Spencer, Nora C. | Mallory, Mark L.
We examined persistent organic pollutant and trace element concentrations in eggs of magnificent frigatebirds (Fregata magnificens), a species of conservation concern breeding in the West Indies. Despite that frigatebirds feed at high positions in tropical marine food chains, we detected low levels of most contaminants, suggesting limited contamination of their prey.
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