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841.
Most marine benthic macroinvertebrate species reproduce via a larval phase but attempts to explain the occurrence of different
larval strategies (feeding or non-feeding, pelagic or benthic) in different habitats have been largely inconclusive. There
have been very few year-round surveys of meroplankton at any latitude and in consequence fundamental data on the diversity,
abundance, and timings of larval life history phases are lacking. There has been considerable debate regarding the viability
of pelagic larvae in cold waters with highly seasonal primary production but there has been only one year-round study of meroplankton
in the Southern Ocean, and that was outside of the Antarctic Circle. We present data from the first year-round survey of meroplankton
assemblages at a location within the Antarctic Circle. We surveyed abundances of meroplanktonic larvae over 1.5 year at Rothera
Point, West Antarctic Peninsula (67°34′S, 68°07′W). Larvae were collected in monthly diver-towed net samples close to the
seabed at 20 and 6 m total water depths at each of three locations and were identified and counted live immediately after
sampling. A total of 99 operationally defined taxonomic types representing 11 phyla were recorded but this is likely to be
an underestimate of true diversity because of inherent difficulties of identification. Larvae were present in all months of
the year and although planktotrophic larvae were more abundant in summer, both feeding and non-feeding types were present
in all months. Comparisons of seasonal larval abundances with data from a settlement study at the same sites and from the
literature show that larvae of mobile adults settle in summer regardless of developmental type, whereas sessile taxa settle
in all seasons. We suggest that this is a consequence of differences in the food requirements of mobile and sessile fauna
and that the availability of food for post-larval juveniles is more critical for survival than factors affecting the larval
stage itself. 相似文献
842.
Jun Bi Yongliang Zhang Bing Zhang 《Frontiers of Environmental Science & Engineering》2010,4(3):361-372
In developing countries, there is controversy over the correct perception regarding environmental and developmental issues. Few studies have examined the perception of low-income nationals in regards to social and environmental issues. This paper looks at the relationship between socio-demographic factors and the groups’ perceived priority regarding environmental and social issues in Wujin County. The results indicated that most residents, specifically the young, government employed and the urban community consider environmental issues to be serious, especially in relation to air pollution and water pollution. Furthermore, many residents feel it is important to rank environmental problems that are related to other social and economic issues, and that environmental protection must be set as a priority in Wujin County. Compared to social issues, environmental concern was greater among the young, government employed, and the urban community, because of their higher education and affluence. In addition, 66.2% of residents consider environmental protection to be more important than economic development. Thus, environmental protection must be set as a high priority in Wujin County, in order to face the many social and environmental challenges inherent in development. 相似文献
843.
It is necessary to identify the hydrogeochemical processes and analyze the causes of groundwater pollution due to the lack of knowledge about the groundwater chemical characteristics and the endemic diseases caused by groundwater pollution in the northern Ordos Cretaceous Basin. In this paper, groundwater chemical facies were obtained using the piper trilinear diagram based on the analysis of 190 samples. The hydrogeochemical processes were identified using ionic ratio coefficient, such as leaching, evaporation and condensation. The causes and sources of groundwater pollution were analyzed by correspondence analysis, and the spatial distribution and enrichment reasons of fluoride ion were analyzed considering the endemic fluorosis emphatically. The results show that leaching, evaporation and condensation, mixing, and anthropogenic activities all had significant impact on hydrogeochemical processes in the study area. However, cation exchange and adsorption effects were strong in the S2 and S3 groundwater flow systems, but weak in S1. Groundwater is mainly polluted by Mn and CODMn in the study area. The landfill leachate, domestic sewage, and other organic pollutants, excessive use of pesticides and fertilizers in agriculture, and pyrite oxidation from long-term and large-scale exploitation of coal are the sources of groundwater pollution. The S1 has the highest degree of groundwater pollution, followed by S2 and S3. High concentration of fluoride ion is mainly distributed in the north and west of study area. Evaporation and condensation and groundwater chemistry component are the most important causes of fluoride ion enrichment. The results obtained in this study will be useful for understanding the groundwater quality for effective management and utilization of groundwater resources and assurance of drinking water safety. 相似文献
844.
Sijia Ai Hongyu Liu Mengjie Wu Guangming Zeng Chunping Yang 《Frontiers of Environmental Science & Engineering》2018,12(6):3
Three acid-producing strains, AFB-1, AFB-2 and AFB-3, were isolated during this study, and their roles in anaerobic digestion of waste activated sludge (WAS) were evaluated. Data of 16S rRNA method showed that AFB-1 and AFB-2 were Bacillus coagulans, and AFB-3 was Escherichia coli. The removal in terms of volatile solids (VS) and total chemical oxygen demand (TCOD) was maximized at 42.7% and 44.7% by inoculating Bacillus coagulans AFB-1. Besides, the optimal inoculum concentration of Bacillus coagulans AFB-1 was 30% (v/v). Solubilization degree experiments indicated that solubilization ratios (SR) of WAS reached 20.8%±2.2%, 17.7%±1.48%, and 11.1%±1.53%. Volatile fatty acids (VFAs) concentrations and compositions were also explored with a gas chromatograph. The results showed that VFAs improved by 98.5%, 53.0% and 11.6% than those of the control, respectively. Biochemical methane potential (BMP) experiments revealed that biogas production increased by 90.7% and 75.3% when inoculating with Bacillus coagulans AFB-1 and AFB-2. These results confirmed that the isolated acid-producing bacteria, especially Bacillus coagulans, was a good candidate for anaerobic digestion of WAS.
相似文献
845.
Quantification and reduction of erroneous differences between images in remote sensing 总被引:1,自引:0,他引:1
The reliability of image data, along with the difficulty of accurately comparing images acquired at different times or from
different sensors, is a generic problem in remote sensing. Measurement repeatability errors occur frequently and can substantially
reduce the system’s ability to reliably quantify real spectral and spatial change in a target. This paper outlines methodologies
for quantifying and reducing erroneous differences between monochrome and multispectral or hyperspectral images. [Each of
these image types is acquired by an instrument that collects light photons across a variable range of the electromagnetic
spectrum (often referred to as an image band). The hyperspectral image is often referred to as a hyperspectral cube with XY
spatial dimensions and many Z bands (spectral demotions)]. In this paper, we specifically discuss the Pixel Block Transform
(PBT), the Spectral Averaging Transform (SAT), and the Wavelet Transform (WAVEL). We briefly address sensor fusion. Results
indicate that the PBT is a powerful cross-noise and repeatability error reducing tool, applicable to monochrome, multispectral,
and hyperspectral images. The SAT is as powerful as the PBT in reducing error but is suitable only for hyperspectral imagery.
WAVEL can reduce some of the finer scale noise, but it is not as powerful in reducing cross-noise as PBT or SAT and it requires
some trial and error for selecting the appropriate wavelet function. It is important that those involved in developing statistically
sound relationships between remotely sensed imagery and other data sources understand the problems and their solutions to
prevent wasting time or developing relationships that are statistically insignificant or unstable, or that lead to faulty
conclusions. 相似文献
846.
847.
848.
Y. P. Kim K. -C. Moon S. -G. Shim J. H. Lee J. Y. Kim K. Fung G. R. Carmichael C. H. Song C. H. Kang H. -K. Kim C. B. Lee 《Atmospheric environment (Oxford, England : 1994)》2000,34(29-30)
Organic carbon (OC) and elemental carbon (EC) in fine particles (PM2.5) at two background sites, Kosan and Kangwha in Korea were measured during intensive field studies between 1994 and 1999. Fine particles were collected on pre-fired quartz filters in a low-volume sampler and analyzed using the selective thermal oxidation method with MnO2 catalyst. The OC and EC concentrations at Kosan located at western tip of Cheju Island in southern Korea are lower than those at Kangwha located at western coastal area in mid-Korean peninsula. Still, the OC concentrations at Kosan are generally higher than those at other background areas in Japan and USA. The EC concentrations at Kosan are lower than or comparable to those at other background areas. The total carbon (TC, sum of OC and EC) to EC ratio values at both sites were higher than those at other background areas in Japan and USA. At Kosan, the OC and EC concentrations when air parcels were from southern China were higher than those when air parcels were coming from northern China. However, at Kangwha, the differences were statistically not clear since most air parcels were from northern China. Except when air parcels were from the North Pacific during summer, the OC and EC concentrations are well correlated indicating that both OC and EC share the same emission/transport characteristics. From the gaseous hydrocarbon data and the OC and EC relationship, it was found that during summer local biogenic emissions of OC might be significant at Kosan. 相似文献
849.
Effect of amorphous silica and silica sand on removal of chromium(VI) by zero-valent iron 总被引:1,自引:0,他引:1
The effect of two surfaces (amorphous silica and silica sand) on the reduction of chromium(VI) by zero-valent iron (Fe(0)) was investigated using batch reactors. The amendment of both surfaces significantly increased the rate and extent of Cr(VI) removal. The rate enhancement by amended surfaces is presumed to result from scavenging of Fe(0)-Cr(VI) reaction products by the provided surfaces, which minimized surface deactivation of Fe(0). The rate enhancing effect was greater for silica compared to sand, and the difference is attributed to silica's higher surface area, greater affinity for reaction products and pH buffering effect. For a given mass of Fe(0), the reactivity and longevity of Fe(0) to treat Cr(VI) increased with increasing dose of silica. Elemental analyses of the reacted iron and silica revealed that chromium removed from the solution was associated with both surfaces, with its mass distribution being approximately 1:1 per mass of iron and silica. The overall result suggests reductive precipitation was a predominant Cr(VI) removal pathway, which involves initial reduction of Cr(VI) to Cr(III), followed by formation of Cr(III)/Fe(III) hydroxides precipitates. 相似文献
850.
Soma Nag Abhijit Mondal Nirjhar Bar Sudip Kumar Das 《Environmental science and pollution research international》2017,24(23):18817-18835
The use of sustainable, green and biodegradable natural wastes for Cr(VI) detoxification from the contaminated wastewater is considered as a challenging issue. The present research is aimed to assess the effectiveness of seven different natural biomaterials, such as jackfruit leaf, mango leaf, onion peel, garlic peel, bamboo leaf, acid treated rubber leaf and coconut shell powder, for Cr(VI) eradication from aqueous solution by biosorption process. Characterizations were conducted using SEM, BET and FTIR spectroscopy. The effects of operating parameters, viz., pH, initial Cr(VI) ion concentration, adsorbent dosages, contact time and temperature on metal removal efficiency, were studied. The biosorption mechanism was described by the pseudo-second-order model and Langmuir isotherm model. The biosorption process was exothermic, spontaneous and chemical (except garlic peel) in nature. The sequence of adsorption capacity was mango leaf > jackfruit leaf > acid treated rubber leaf > onion peel > bamboo leaf > garlic peel > coconut shell with maximum Langmuir adsorption capacity of 35.7 mg g?1 for mango leaf. The treated effluent can be reused. Desorption study suggested effective reuse of the adsorbents up to three cycles, and safe disposal method of the used adsorbents suggested biodegradability and sustainability of the process by reapplication of the spent adsorbent and ultimately leading towards zero wastages. The performances of the adsorbents were verified with wastewater from electroplating industry. The scale-up study reported for industrial applications. ANN modelling using multilayer perception with gradient descent (GD) and Levenberg-Marquart (LM) algorithm had been successfully used for prediction of Cr(VI) removal efficiency. The study explores the undiscovered potential of the natural waste materials for sustainable existence of small and medium sector industries, especially in the third world countries by protecting the environment by eco-innovation. 相似文献