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Air quality modeling in Bogotá, Colombia using local emissions and natural mitigation factor adjustment for re-suspended particulate matter 全文
2017
Nedbor-Gross, Robert | Henderson, Barron H. | Pérez-Peña, María Paula | Pachón, Jorge E.
We characterize particulate matter within the megacity Bogotá, Colombia using the Community Multi-scale Air Quality (CMAQ) model. This work builds on previous efforts to develop representative meteorological simulations and emission inventories. Emissions are dominated by re-suspended particulate matter (PM), which are highly dependent on land-surface characterization and meteorology. We update previous re-suspended PM emission inventories to account for improved meteorological simulations and then we predict daily PM. Incorporating the latest meteorology and land-surface characteristics the re-suspended PM are on average reduced to 43% of their original estimate. The re-suspended PM reductions are caused by natural mitigation impacts on unpaved roads, which is extremely sensitive to relative humidity. With the updated emission inventory, the model predicts daily average PM10 of 59.4 (±1.0) μg/m3 compared to the observed values 58.3 (±0.7) μg/m3 at monitoring stations. The model performs well compared to literature recommended performance statistics except at two stations with outlier mean fractional bias and error. The remaining 10 stations have an overall mean fractional bias of 9.7% (stations ranging from −23.6–44.5%) and overall mean fractional error of 39.1% (stations ranging from 31.9 to 48.4%). Sensitivity analysis shows that both outlier stations are insensitive to the adjustments to resuspended road dust and are likely missing proximate sources from outside of the domain, or unknown sources within the domain. Still, within the core of Bogotá, the model is capturing the variability of mass concentration. Future work should improve the chemical speciation of particulate emissions to better characterize specific source/receptor relationships.
显示更多 [+] 显示较少 [-]Sedimentary heavy metal(loid) contamination in the Veracruz shelf, Gulf of Mexico: A baseline survey from a rapidly developing tropical coast 全文
2017
Celis-Hernandez, Omar | Rosales Hoz, Leticia | Cundy, Andrew B. | Carranza-Edwards, Arturo
This study examines sediment texture, geochemistry and sediment accumulation in cores from four sites in the Veracruz shelf area of the Gulf of Mexico, to assess the inputs of heavy metal(loid)s (and their potential biological impacts) in this carbonate-dominated shelf system, and to examine the rate of sedimentation near to the mouths of the La Antigua and Jamapa Rivers. The use of different pollution indices showed enrichment with Pb in all cores studied, although based on sediment quality guidelines As was the only element that has potential to occasionally cause damage to the benthic organisms present in the area. Heavy metal(loid) and sediment input from terrestrial and coastal sources is limited compared to more proximal, near-shore areas. The sediment core data presented however give a baseline dataset for heavy metal(loid) concentrations in the Veracruz shelf, against which future anthropogenic inputs can be assessed.
显示更多 [+] 显示较少 [-]Effects of elevated ammonium on the transcriptome of the stony coral Pocillopora damicornis 全文
2017
Yuan, Chao | Zhou, Zhi | Zhang, Yidan | Huangmei, | Yu, Xiaopeng | Ni, Xingzhen | Tang, Jia | Huang, Bo
The survival of corals worldwide has been seriously threatened by eutrophication events concomitant with the increase in ocean pollution. In the present study, whole transcriptomes of the stony coral Pocillopora damicornis exposed to elevated ammonium were sequenced. A total of 121,366,983 pair-end reads were obtained, and 209,337 genes were assembled, including 42,399 coral-derived and 54,874 zooxanthella-derived genes. Further, a comparison of the control versus stress group revealed 6572 differentially expressed genes. For 1015 significantly upregulated genes, 24 GO terms were overrepresented, among which 3 terms related to apoptosis and cell death induction included one caspase, five bcl-2-like proteins, and two tumor necrosis factor receptor superfamily member genes. For 5557 significantly downregulated genes, the top 10 overrepresented terms were related to metabolism and signal transduction. These results indicate that apoptosis and cell death could be induced under elevated ammonium, suggesting that metabolic regulation and signal transduction might be involved in the reconstruction of the coral–zooxanthellae symbiotic balance in the stony coral P. damicornis.
显示更多 [+] 显示较少 [-]Analysing how plants in coastal wetlands respond to varying tidal regimes throughout their life cycles 全文
2017
Xie, Tian | Cui, Baoshan | Li, Shanze
Important to conserve plant species in coastal wetlands throughout their life cycle. All life stages in these habitats are exposed to varying tidal cycles. It is necessary to investigate all life stages as to how they respond to varying tidal regimes. We examine three wetlands containing populations of an endangered halophyte species, each subjected to different tidal regimes: (1). wetlands completely closed to tidal cycles; (2). wetlands directly exposed to tidal cycles (3). wetlands exposed to a partially closed tidal regime. Our results showed that the most threatened stage varied between wetlands subjected to these varying tidal regimes. We hypothesis that populations of this species have adapted to these different tidal regimes. Such information is useful in developing management options for coastal wetlands and modifying future barriers restricting tidal flushing.
显示更多 [+] 显示较少 [-]Blood cadmium and metallothionein concentrations in females of two sympatric pinnipeds species 全文
2017
Polizzi, P. | Romero, M.B. | Chiodi Boudet, L.N. | Ponce de León, A. | Medici, S. | Costas, A. | Rodríguez, D. | Gerpe, M.
Otaria flavescens (SASL) and Arctocephalus australis (SAFS) are endemic of South America. The aims were to assess Cd concentrations in red blood cells (RBC) and plasma from free living females of both species; and to establish metallothioneins (MT) levels in blood fractions and the possible relationship between MTs and Cd. Blood of fifteen SASL and eight SAFS females from Isla de Lobos were analyzed (years 2010–2011). All animals showed Cd levels above the detection limit. Cd concentrations on SAFS were higher than those of SASL, however, no significant differences were observed on metal concentrations between cell fractions by species. Metal levels were associated with a natural presence and ecological-trophic habits of the prey items. On SASL the MT concentrations between fractions were similar; whereas, SAFS plasma concentrations were higher than RBC. The results reported constitute the first information on Cd and MT blood levels in these species.
显示更多 [+] 显示较少 [-]Continuous monitoring of noise levels in the Gulf of Catania (Ionian Sea). Study of correlation with ship traffic 全文
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).
显示更多 [+] 显示较少 [-]Ubiquity of microplastics in coastal seafloor sediments 全文
2017
Ling, S.D. | Sinclair, M. | Levi, C.J. | Reeves, S.E. | Edgar, G.J.
Microplastic pollutants occur in marine environments globally, however estimates of seafloor concentrations are rare. Here we apply a novel method to quantify size-graded (0.038–4.0mm diam.) concentrations of plastics in marine sediments from 42 coastal and estuarine sites spanning pollution gradients across south-eastern Australia. Acid digestion/density separation revealed 9552 individual microplastics from 2.84l of sediment across all samples; equating to a regional average of 3.4 microplastics·ml−1 sediment. Microplastics occurred as filaments (84% of total) and particle forms (16% of total). Positive correlations between microplastic filaments and wave exposure, and microplastic particles with finer sediments, indicate hydrological/sediment-matrix properties are important for deposition/retention. Contrary to expectations, positive relationships were not evident between microplastics and other pollutants (heavy metals/sewage), nor were negative relationships with neighbouring reef biota detected. Rather, microplastics were ubiquitous across sampling sites. Positive associations with some faunal-elements (i.e. invertebrate species richness) nevertheless suggest high potential for microplastic ingestion.
显示更多 [+] 显示较少 [-]Petroleum hydrocarbon toxicity to corals: A review 全文
2017
Turner, Nicholas R. | Renegar, D Abigail
The proximity of coral reefs to coastal urban areas and shipping lanes predisposes corals to petroleum pollution from multiple sources. Previous research has evaluated petroleum toxicity to coral using a variety of methodology, including monitoring effects of acute and chronic spills, in situ exposures, and ex situ exposures with both adult and larval stage corals. Variability in toxicant, bioassay conditions, species and other methodological disparities between studies prevents comprehensive conclusions regarding the toxicity of hydrocarbons to corals. Following standardized protocols and quantifying the concentration and composition of toxicant will aid in comparison of results between studies and extrapolation to actual spills.
显示更多 [+] 显示较少 [-]Arsenic and mercury concentrations in marine fish sourced from local fishermen and fish markets in mine-impacted communities in Ratatotok Sub-district, North Sulawesi, Indonesia 全文
2017
Bentley, Keith | Soebandrio, Amin
Mesel gold mine, Ratatotok Sub-district, North Sulawesi, Indonesia deposited about 4.5millionm3 of detoxified tailings containing arsenic (As) and mercury (Hg) via a submarine pipeline into Buyat Bay. As and Hg analysis of 216 fish muscle tissue composites from subsistence fishermen, local markets and a reference market confirmed that mean As levels were comparable between locations (range 1.71 to 2.12mg/kg wet weight (ww)) and <10% of the Australia New Zealand standard. Mean Hg concentrations were highest for the artisanal fishermen group (0.23mg/kg ww), similar between the local markets (0.11–0.14mg/kg ww) and lower at the reference market (0.04mg/kg ww). A 12-month fish availability study identified that the results were due to the different coral and deep ocean species assemblages. All mean values were <50% of the FAO/WHO/Codex standard for Hg. The results confirmed that there was no contamination from the deposited submarine tailings.
显示更多 [+] 显示较少 [-]A new perspective of particle adsorption: Dispersed oil and granular materials interactions in simulated coastal environment 全文
2017
Meng, Long | Bao, Mutai | Sun, Peiyan
This study, adsorption behaviors of dispersed oil in seawaters by granular materials were explored in simulation environment. We quantitatively demonstrated the dispersed oil adsorbed by granular materials were both dissolved petroleum hydrocarbons (DPHs) and oil droplets. Furthermore, DPHs were accounted for 42.5%, 63.4%, and 85.2% (35.5% was emulsion adsorption) in the adsorption of dispersed oil by coastal rocks, sediments, and bacterial strain particles respectively. Effects of controlling parameters, such as temperature, particle size and concentration on adsorption of petroleum hydrocarbons were described in detail. Most strikingly, adsorption concentration was followed a decreasing order of bacterial strain (0.5–2μm)>sediments (0.005–0.625mm)>coastal rocks (0.2–1cm). With particle concentration or temperature increased, adsorption concentration increased for coastal rocks particle but decreased for sediments particle. Besides, particle adsorption rate of petroleum hydrocarbons (n-alkanes and PAHs) was different among granular materials during 60 days.
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