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Mathivanan Krishnamurthy Chandirika Jayaraman Uthaya Vinothkanna Annadurai Govindarajan R. K. Meng Delong Yin Huaqun 《Journal of Polymers and the Environment》2021,29(6):1742-1751
Journal of Polymers and the Environment - In this study, the production and physicochemical characterization of exopolysaccharide (EPS) produced by Lysinibacillus fusiformis KMNTT-10 were... 相似文献
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Management of riparian habitats has been recognized for its importance in reducing instream effects of agricultural nonpoint
source pollution. By serving as a buffer, well structured riparian habitats can reduce nonpoint source impacts by filtering
surface runoff from field to stream. A system has been developed where key characteristics of riparian habitat, vegetation
type, height, width, riparian and shoreline bank slope, and land use are classified as discrete categorical units. This classification
system recognizes seven riparian vegetation types, which are determined by dominant plant type. Riparian and shoreline bank
slope, in addition to riparian width and height, each consist of five categories. Classification by discrete units allows
for ready digitizing of information for production of spatial maps using a geographic information system (GIS). The classification
system was tested for field efficiency on Tom Beall Creek watershed, an agriculturally impacted third-order stream in the
Clearwater River drainage, Nez Perce County, Idaho, USA. The classification system was simple to use during field applications
and provided a good inventory of riparian habitat. After successful field tests, spatial maps were produced for each component
using the Professional Map Analysis Package (pMAP), a GIS program. With pMAP, a map describing general riparian habitat condition
was produced by combining the maps of components of riparian habitat, and the condition map was integrated with a map of soil
erosion potential in order to determine areas along the stream that are susceptible to nonpoint source pollution inputs. Integration
of spatial maps of riparian classification and watershed characteristics has great potential as a tool for aiding in making
management decisions for mitigating off-site impacts of agricultural nonpoint source pollution. 相似文献
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本文对天津市28个陆源污染物排海口进行调查分析,在天津海域进行了较大范围的实地监测取得了大量的有关潮汐、余流场、水位及各种污染物2场的资料,建立了多种水质模型。在此基础上结合天津近岸海域独特的地理位置及地形地貌进行经济、环境、效益的综合分析,为渤海典型海域实施污水海洋处置工程的可靠性提供了可借鉴的依据。 相似文献
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Macroinvertebrate Community Structure Along the Longitudinal Gradient of an Agriculturally Impacted Stream 总被引:7,自引:0,他引:7
/ Lapwai Creek, an agriculturally impacted stream in northern Idaho, was sampled seasonally over a two-year period to determine if macroinvertebrate community composition changed along the longitudinal gradient and if changes followed predictions of the river continuum concept. Possible relationships between changes in food resource availability and community structure were also examined. Benthic invertebrates were collected at eight locations along the longitudinal gradient of Lapwai Creek using a Hess sampler. Random skewer analysis suggested there was no longitudinal gradient for either number of individuals or functional feeding group composition. Cluster analysis revealed that all locations, excluding a site receiving outflow from a small, eutrophic reservoir, had a similar community structure, further suggesting that invertebrate community composition remained consistent along the longitudinal gradient of the stream. The community was dominated at all sites, excluding the site below the reservoir, by functionalgrazers. Shredders were rare throughout Lapwai Creek, even in areas where healthy riparian vegetation still remained. Studies of other streams within the drainage basin show that many species found in the upper reaches of these streams, where agricultural impacts are low, were absent throughout the length of Lapwai Creek. Data collected concurrently with macroinvertebrates indicated that the input, storage, and transport of particulate organic matter was low throughout the stream, whereas periphyton abundance was high. The absence of longitudinal changes, despite flowing through three distinct geomorphological regions, and the grouping of all sites except one by cluster analysis for both dominant taxa and functional feeding groups suggest that agricultural alteration has influenced community structure of Lapwai Creek, resulting in a relatively homogeneous assemblage of macroinvertebrates capable of tolerating agricultural nonpoint source pollution. Additional support for this hypothesis is the high abundance of one food source, periphyton, and the small quantities of terrestrially derived organic matter. The abundance of the former and the rarity of the latter can be attributed to alteration of the drainage basin resulting from agricultural activities through inputs of fertilizers that generated high nutrient concentrations and the removal of riparian vegetation to clear more land for agriculture and provide increase access to the stream.KEY WORDS: Agriculture; Longitudinal patterns; Macroinvertebrates; Nonpoint source; River continuum 相似文献
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Allochthonous input of organic matter from different riparian habitats of an agriculturally impacted stream 总被引:1,自引:0,他引:1
Lapwai Creek, an agriculturally impacted stream in northern Idaho, was examined to determine longitudinal patterns of particulate
allochthonous input from different riparian vegetation types. The stream, characterized by extensive removal of mature vegetation,
was classified as having four riparian vegetation types: herbaceous, herbaceous-shrub mix, shrubs, and deciduous trees. Litterfall
from each vegetation type was measured monthly for two years at eight locations along Lapwai Creek using 0.1-m2 baskets. Litterfall was lowest for herbaceous habitats and highest for deciduous tree habitats. Annual litterfall was low
in the headwaters, which flow through an open meadow and deep canyon, and increased from the canyon-floodplain transition
downstream to the first fifth-order site. Annual litterfall decreased markedly at the last two fifth-order stream sections.
Differences in annual input rates between section 6 and sections 7 and 8, all of which are fifth order, can be attributed
to removal of climax riparian vegetation. Estimates of actual and potential annual allochthonous income for each site suggest
that current detrital inputs to Lapwai Creek are less than could be achieved if greater quantities of climax vegetation were
still present. Lower rates of allochthonous inputs to Lapwai Creek may result in a system with detrital dynamics and macroinvertebrate
communities different from that of comparable undisturbed streams of this region. 相似文献
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J. H. Martin P. D. Elliott V. C. Anderlini D. Girvin S. A. Jacobs R. W. Risebrough R. L. Delong W. G. Gilmartin 《Marine Biology》1976,35(1):91-104
High premature birth rates have been observed in the rookeries of the California sea lion Zalophus californianus since 1968. The reasons for the premature pupping are complex and, hence, not well understood, although leptospirosis infection and elevated PCB and DDT residues have been implicated. We were interested in determining what role trace and major elements played in these events. Livers and kidneys from 10 normal parturient and 10 premature parturient mothers and their pups were analyzed for Hg, Se, Br, Cd, Ag, Cu, Fe, Zn, Mn, K, Na, Ca, and Mg in order to detect differences that might exist between the two groups. A further objective was to establish how these elements varied in relation to each other in the normal and abnormal sea lions. Our results revealed that Hg, Se, Cd, and Br levels were significantly higher in the livers of the normal mothers and that these elements were all in balance (highly correlated) with each other. This was especially true for Hg, Se, and Br. In mothers with high concentrations of these elements (e.g. Hg greater than 800 g/g dry weight), atomic ratios of approximately 1Hg:1Se:1Br were observed. Atomic Se:Hg ratios were also near unity in the abnormal mothers; however, Br concentrations were always severely depressed in these individuals. Normal full-term pups had higher hepatic levels of Hg and Se, and near-perfect 1:1 Se:Hg atomic ratios were almost always observed. In contrast, the livers of the premature pups appeared to be deficient in Hg, and, consequently, elevated Se:Hg ratios were always found. In almost all cases, the premature pups had increased concentrations of Na, Ca, and Br. Levels of these elements were correlated with their Se:Hg ratios. Amounts of Mn and Cu were reduced in the premature pups and negatively correlated with Se:Hg ratios. The results suggest that balance between elements is of more importance than absolute concentration when the possible effects of toxic elements are considered. It also appears that bromine may be important in the detoxification process involving Se and Hg and perhaps Cd as well; i.e., every mother that had Br in balance with Hg, Cd, and Se had a normal pup, while every mother that lacked sufficient Br had a premature pup. The question of whether Hg detoxifies Se is also raised. All the normal pups had Se:Hg atomic ratios of less than 2.2, while all the premature pups had reduced Hg amounts and Se:Hg ratios above 3.4. 相似文献
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采用WRF/Chem模式对2004年4月6—8日发生在广东省一次典型冷锋酸雨过程的气象场和污染物分布进行数值模拟,分析此次酸雨过程中致酸污染物SO2、NOx、硫酸盐气溶胶和硝酸盐气溶胶的主要分布特征,进而探讨此次酸雨的成因.结果表明,冷锋过境前,边界层高度较低,不利于污染物扩散,主要是局地排放致酸;冷锋过境形成了逆温层,污染物在逆温层内成片状均匀分布,使广东省出现大范围的酸雨.污染物浓度分布的模拟结果表明:SO2以本地源为主;NOx扩散范围较SO2广,分布更均匀;硫酸盐气溶胶和硝酸盐气溶胶6日主要分布在粤北,7日成大范围片状分布,与pH值的分布特征相似. 相似文献
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Chen Zexi Zhang Delong Jiang Haoran Liu Weiwei Liu Tianhua Zheng Youzhe Zhang Yan Li Meicheng 《Environmental science and pollution research international》2020,27(32):40244-40252
Environmental Science and Pollution Research - The coal-to-electricity project (CTEP) using electricity instead of coal for heating is a significant measure to cope with climate change and air... 相似文献