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Simulation of CO2–water–rock interactions on geologic CO2 sequestration under geological conditions of China 全文
2013
Wang, Tianye | Wang, Huaiyuan | Zhang, Fengjun | Xu, Tianfu
The main purpose of this study focused on the feasibility of geologic CO2 sequestration within the actual geological conditions of the first Carbon Capture and Storage (CCS) project in China. This study investigated CO2–water–rock interactions under simulated hydrothermal conditions via physicochemical analyses and scanning electron microscopy (SEM). Mass loss measurement and SEM showed that corrosion of feldspars, silica, and clay minerals increased with increasing temperature. Corrosion of sandstone samples in the CO2-containing fluid showed a positive correlation with temperature. During reaction at 70°C, 85°C, and 100°C, gibbsite (an intermediate mineral product) formed on the sample surface. This demonstrated mineral capture of CO2 and supported the feasibility of geologic CO2 sequestration. Chemical analyses suggested a dissolution–reprecipitation mechanism underlying the CO2–water–rock interactions. The results of this study suggested that mineral dissolution, new mineral precipitation, and carbonic acid formation-dissociation are closely interrelated in CO2–water–rock interactions.
显示更多 [+] 显示较少 [-]Guiding principles for the improved governance of port and shipping impacts in the Great Barrier Reef 全文
2013
Grech, A. | Bos, M. | Brodie, J. | Coles, R. | Dale, A. | Gilbert, R. | Hamann, M. | Marsh, H. | Neil, K. | Pressey, R.L. | Rasheed, M.A. | Sheaves, M. | Smith, A.
The Great Barrier Reef (GBR) region of Queensland, Australia, encompasses a complex and diverse array of tropical marine ecosystems of global significance. The region is also a World Heritage Area and largely within one of the world’s best managed marine protected areas. However, a recent World Heritage Committee report drew attention to serious governance problems associated with the management of ports and shipping. We review the impacts of ports and shipping on biodiversity in the GBR, and propose a series of guiding principles to improve the current governance arrangements. Implementing these principles will increase the capacity of decision makers to minimize the impacts of ports and shipping on biodiversity, and will provide certainty and clarity to port operators and developers. A ‘business as usual’ approach could lead to the GBR’s inclusion on the List of World Heritage in Danger in 2014.
显示更多 [+] 显示较少 [-]The value of the seagrass Posidonia oceanica: A natural capital assessment 全文
2013
Vassallo, Paolo | Paoli, Chiara | Rovere, Alessio | Montefalcone, Monica | Morri, Carla | Bianchi, Carlo Nike
Making nature’s value visible to humans is a key issue for the XXI century and it is crucial to identify and measure natural capital to incorporate benefits or costs of changes in ecosystem services into policy. Emergy analysis, a method able to analyze the overall functioning of a system, was applied to reckon the value of main ecosystem services provided by Posidonia oceanica, a fragile and precious Mediterranean seagrass ecosystem. Estimates, based on calculation of resources employed by nature, resulted in a value of 172€m−2a−1. Sediment retained by meadow is most relevant input, composing almost the whole P. oceanica value. Remarks about economic losses arising from meadow regression have been made through a time-comparison of meadow maps. Suggested procedure represents an operative tool to provide a synthetic monetary measure of ecosystem services to be employed when comparing natural capital to human and financial capitals in a substitutability perspective.
显示更多 [+] 显示较少 [-]Mercury and selenium biomagnification in a Brazilian coastal food web using nitrogen stable isotope analysis: A case study in an area under the influence of the Paraiba do Sul River plume 全文
2013
Kehrig, Helena A. | Seixas, Tercia G. | Malm, Olaf | Di Beneditto, Ana Paula M. | Rezende, Carlos E.
Mercury (Hg), selenium (Se) and nitrogen (δ15N) stable isotope were assessed in a tropical food web of Rio de Janeiro’s north coast. Isotopic data on muscle suggest a difference related to this parameter along the food web; where top-predators (cetacean and voracious fish) displayed heavier δ15N over the entire food web. Both top-predators presented similar δ15N values. Cetacean displayed higher Hg and lower Se than voracious fish. Five trophic positions (TP) were found in relation to primary consumer as baseline, ranging from 2.0 to 4.0. Positive relationships were found between trace-element and δ15N. The slope of regression equations (0.11 for Se and 0.21 for Hg) and food web magnification factors (2.4 for Se and 5.4 for Hg) showed that Hg presented higher rate of increase over the food web. Simultaneous measurements of trace-elements and ecological tracers emphasize the importance of TP into the trophic structure and distribution of Hg and Se throughout the food web.
显示更多 [+] 显示较少 [-]Pelagic microplastics around an archipelago of the Equatorial Atlantic 全文
2013
Ivar do Sul, Juliana A. | Costa, Monica F. | Barletta, Mario | Cysneiros, Francisco José A.
Plastic marine debris is presently widely recognised as an important environmental pollutant. Such debris is reported in every habitat of the oceans, from urban tourist beaches to remote islands and from the ocean surface to submarine canyons, and is found buried and deposited on sandy and cobble beaches. Plastic marine debris varies from micrometres to several metres in length and is potentially ingested by animals of every level of the marine food web. Here, we show that synthetic polymers are present in subsurface plankton samples around Saint Peter and Saint Paul Archipelago in the Equatorial Atlantic Ocean. To explain the distribution of microplastics around the Archipelago, we proposed a generalised linear model (GLM) that suggests the existence of an outward gradient of mean plastic-particle densities. Plastic items can be autochthonous or transported over large oceanic distances. One probable source is the small but persistent fishing fleet using the area.
显示更多 [+] 显示较少 [-]Drivers of estuarine benthic species distribution patterns following a restoration of a seagrass bed: A functional trait analyses 全文
2013
Dolbeth, Marina | Cardoso, Patricia | Grilo, Tiago | Raffaelli, Dave | Pardal, Miguel Ângelo
We integrate information on functional diversity (FD) patterns from estuarine intertidal benthic communities from different habitats and along a temporal disturbance gradient, to understand the drivers of species coexistence patterns. Species and traits’ biomass levels seemed to be first determined by habitat filtering, selecting those traits better adapted to the biologically challenging estuarine environment. Within that subset of traits and within each habitat, biotic interactions were probably high, as evidenced by high α-diversity and community weighted mean differences. The former patterns hold for the disturbance/recovery scenario considered. However, as the estuary recovered, biomass became more distributed among different trait categories, consistent with increases in FD when the seagrass started to increase. Policy towards the restoration of seagrass bed and other biogenic structures, and improving the connectivity within adjacent systems were confirmed and suggested, as this would imply higher FD and potentially higher resilience to disturbance within the estuarine intertidal system.
显示更多 [+] 显示较少 [-]Personal exposure of commuters in public transport to PM2.5 and fine particle counts 全文
2013
Onat, Burcu | Stakeeva, Baktygul
To investigate fine particulate air pollution generated by public transport and its microenvironment, PM2.5 measurements and particle number counts for six particle size ranges (0.3–0.5 µm, >0.5–1.0 µm, >1.0–3.0 µm, >3.0– 5.0 µm, >5.0–10 µm and >10 µm) were obtained for four public transport modes: bus, metro–bus, car and walking. The measurements were repeated for each transport mode twice a day for 7–10 measurement days. The highest average PM2.5 concentration was measured inside a bus (106 µg/m3) during rush hours. The highest single peak measurement was a concentration of 316 µg/m3 for walking during non–rush hours. The PM2.5 level in a car with the air conditioning fan off was approximately 2.5 times lower than the level with the air conditioning fan on. Moderate correlations were found between PM2.5 concentrations and wind speed. Weak correlations were found between PM2.5 concentrations, relative humidity and temperature. The results showed that the diameters of most of the particles were smaller than 0.5 µm, regardless of the transport mode. The average fine particle number (size range 0.3–0.5) for all transport modes ranged from 54 647 to 209 746 particles/103 cm3 during rush hours and from 49 423 to 184 866 particles/103 cm3 during non–rush hours.
显示更多 [+] 显示较少 [-]Occurrence of microplastics in the gastrointestinal tract of pelagic and demersal fish from the English Channel 全文
2013
Lusher, A.L. | McHugh, M. | Thompson, R.C.
Microplastics are present in marine habitats worldwide and laboratory studies show this material can be ingested, yet data on abundance in natural populations is limited. This study documents microplastics in 10 species of fish from the English Channel. 504 Fish were examined and plastics found in the gastrointestinal tracts of 36.5%. All five pelagic species and all five demersal species had ingested plastic. Of the 184 fish that had ingested plastic the average number of pieces per fish was 1.90±0.10. A total of 351 pieces of plastic were identified using FT-IR Spectroscopy; polyamide (35.6%) and the semi-synthetic cellulosic material, rayon (57.8%) were most common. There was no significant difference between the abundance of plastic ingested by pelagic and demersal fish. Hence, microplastic ingestion appears to be common, in relatively small quantities, across a range of fish species irrespective of feeding habitat. Further work is needed to establish the potential consequences.
显示更多 [+] 显示较少 [-]Carbon and nitrogen stable isotope ratios and mercury concentration in the scalp hair of residents from Taiji, a whaling town 全文
2013
Endo, Tetsuya | Hayasaka, Moriaki | Hisamichi, Yohsuke | Kimura, Osamu | Haraguchi, Koichi
We analyzed stable isotope ratios of carbon (δ13C) and nitrogen (δ15N) as well as mercury (Hg) concentration in the scalp hair of Japanese who consumed whale meat and those who did not, and investigated the relationships among the δ13C and δ15N values and Hg concentration. The average δ15N and δ13C values of whale meat-eaters (10.11‰ and −18.5‰) were significantly higher than those of non-eaters (9.28‰ and −18.9‰), respectively. The average Hg concentration of whale meat-eaters (20.6μg/g) was significantly higher than that of non-eaters (2.20μg/g). Significant positive correlations were found between the δ13C and δ15N values and between the δ15N value and Hg concentration in the hair of whale meat-eaters, while the correlation between the δ15N value and Hg concentration was not statistically significant in the non-eaters. The consumption of whale meat may increase Hg concentration as well as δ15N and δ13C values in scalp hair.
显示更多 [+] 显示较少 [-]The effects of wastewater effluent and river discharge on benthic heterotrophic production, organic biomass and respiration in marine coastal sediments 全文
2013
Burd, B. | MacDonald, T. | Bertold, S.
We examine effects of high river particulate flux and municipal wastewater effluent on heterotrophic organic carbon cycling in coastal subtidal sediments. Heterotrophic production was a predictable (r2=0.95) proportion (56%) of oxidized OC flux and strongly correlated with organic/inorganic flux. Consistent growth efficiencies (36%) occurred at all stations. Organic biomass was correlated with total, OC and buried OC fluxes, but not oxidized OC flux. Near the river, production was modest and biomass high, resulting in low P/B. Outfall deposition resulted in depleted biomass and high bacterial production, resulting in the highest P/B. These patterns explain why this region is production “saturated”. The δ15N in outfall effluent, sediments and dominant taxa provided insight into where, and which types of organisms feed directly on fresh outfall particulates, on older, refractory material buried in sediments, or utilize chemosynthetic symbiotic bacteria. Results are discussed in the context of declining bottom oxygen conditions along the coast.
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