检索结果-南通市图书馆

Irrigation system and land use effect on surface water quality in river, at lake dianchi, Yunnan, China

Journal of Environmental Sciences 2013年第6期25卷 1107-1116页

作者： Takashi Tanaka Takahiro Sato Kazuo Watanabe Ying Wang Dan Yang Hiromo Inoue Kunzhi Li Tatsuya Inamura Graduate School of Agriculture Kyoto University Biotechnology Research Center Kunming University of Science and Technology Crop and Environmental Sciences Division International Rice Research Institute Center for Southeast Asian Studies Kyoto University

The surface water samples were collected in river Dahe and its tributaries, which flow into severely eutrophic lake dianchi, Yunnan Province, China, in order to elucidate factors controlling water quality fluctuations. The temporal and spatial distribution of water quality tendency was observed. The water quality of each river is dependent on the hydrology effect such water gate and circulating irrigation system. We must consider the hydrology effect to accurately understand water quality variations of river in this study field. In river without highly circulating irrigation system or water gate effect, the downstream nitrate nitrogen （NO3-N） concentration increase occurred in area dominated by open field cultivation, whereas the NO3-N concentration was constant or decreased in area dominated by greenhouse land use. This result suggests that greenhouse covers the soil from precipitation, and nitrate load of greenhouse could be less than that of open field cultivation while the rainfall event. In the upper reaches of river, where is dominated by open field cultivation, there were no sharp increase dissolved molybdate reactive phosphorus and total phosphorus concentration, but P load was accumulated in the lower reaches of river, whose predominant land use is greenhouse. Although the P sources is unclear in this study, greenhouse area may have potential of P loads due to its high P content in greenhouse soil. Considering hydrology effect is necessary to determine what the major factor is influencing the water quality variation, especially in area with highly complicated irrigation system in this studying site.

关键词： lake dianchi eutrophication surface water quality land use plastic greenhouse circulating irrigation

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Regime shift in lake dianchi(China) during the last 50 years

引用

Journal of Oceanology and Limnology 2018年第4期36卷 1075-1090页

作者： WANG Yingcai WANG Weibo WANG Zhi LI Genbao LIU Yongding Yangtze Valley Water Environment Monitoring Center Wuhan 430010 China Institute of Hydrobiology Chinese Academy of Sciences Wuhan 430072 China Laboratory of Aquatic Botany and Watershed Ecology Wuhan Botanical Garden Chinese Academy of Sciences Wuhan 430074 China Institute of Geodesy and Geophysics Chinese Academy of Sciences Wuhan 430077 China

lake dianchi has undergone accelerated alternations resulting from human activities during the last 50 years, and provides an exceptional example for the study of regime shift in a shallow lake. Focusing on regime shift, we systematically studied and analysed alternations of key components of its ecosystem, including water parameters, phytoplankton and zooplankton biomass, macrophyte composition and fish populations. We found that the shifting course of lake dianchi went through three major phases, corresponding to three distinct states: Phase I clean, stable state during the 1950 s; Phase II transitional state during the 1970 s–1980 s; and phase III stable, turbid state since 1993. We analysed all data and samples, identifying the threshold concentrations at which regime shift occurred: total nitrogen(TN) and phosphorus(TP) reaching 1.2 mg/L and 0.13 mg/L, respectively. Results from this study strongly suggest that the increasing input of external nutrients, reclaiming land from the lake and foreign fish invasion were major inducements to the accelerated shift of lake dianchi to its turbid, stable state. These findings provide valuable guidelines for potential efforts to reverse this unnatural process in lake dianchi. The restoration may need to:(1) thoroughly and accurately identify pollution sources to control and reduce excessive external nutrients flowing into the lake;(2) return reclaimed land to the lake and recover the littoral zone to its natural state to facilitate increased restoration of macrophytes; and(3) strategically adjust fish populations by reducing benthivorous and filter-feeding fish populations that prey on zooplankton, while enlarging zooplankton populations to control phytoplankton biomass.

关键词： regime shift lake dianchi eutrophication altemative state driving force ecosystem

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Comprehensive evaluation of heavy metal contamination of sediment in lake dianchi by using modified AHP method and ^(137)Cs dating

引用

Frontiers of Environmental Science & Engineering 2008年第3期2卷 370-379页

作者： Yan ZHANG Xiang GAO Zhenyu ZHONG Xihai DENG Buzhuo PENG School of Geographic and Oceanographic Sciences Nanjing UniversityNanjing 210093China State Key Laboratory of Soil Sustainable Agriculture Institute of Soil SciencesChinese Academy of SciencesNanjing 210008China

Through the use of general sampling and measurement by ^(137)Cs dating,problems regarding the absence of monitoring data can easily be ***,weighted values need to be determined while Environment Quality Comprehensive Index(EQCI)is commonly used as applied in environmental quality comprehensive *** order to overcome the subjectivity in determining weights,the modified Analytical Hierarchy Process(AHP)method was *** modified AHP method involved the following key procedures:First,the parameters y_(i1) and y_(i2) were calculated based on the monitoring data;second,the factors were put in order according to the symbol and value of y_(i1) and y_(i2);third,the continuous odd integers,which represented the importance of factors,were given to factors according to their seating order;and,fourth,the factor weights were determined from the pair-wise comparison matrix calculated by the ratio of the given odd ***,the weights were completely based on the monitoring *** the present study,the comprehensive quality of sediments in five sections of lake dianchi were evaluated and the results indicated that the current contamination of sediments in each lake section is much more serious than at any other time in history.

关键词： ^(137)Cs dating modified AHP method environment quality comprehensive evaluation heavy metal contamination of sediment lake dianchi

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

AAssessment of the spatial-temporal eutrophic character in the lake dianchi

引用

Journal of Geographical Sciences 2005年第1期15卷 37-43页

作者： XINGKexia GUOHuaicheng SUNYanfeng HUANGYongtai CollegeofEnvironmentalSciences Peking-UniversityBeijing100871China YunnanInstituteofEnvironmentalScience Kunming650034China

Water-quality deterioration and eutrophication of the lake dianchi have acquired more and more attention in the last few decades. In this paper, the spatial and temporal eutrophication status of the lake dianchi was assessed. The comprehensive trophic state index was chosen to assess the trophic status of the lake dianchi in the past 13 years. The result reveals that the trophic condition of Caohai is more serious than that of Waihai. Most of time Caohai was in extremely hypereutrophic state from 1988 to 2000. The trophic condition of Waihai had a worsening tendency from 1988 to 2000. Waihai was in eutrophic state before 1995, but it got in a hypereutrophic state after 1995. It was pointed out that TN and TP were the two biggest contributors of CTSIM in both Caohai and Waihai.

关键词： lake dianchi Caohai Waihai eutrophication assessement TSI

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Microbial biodegradation of microcystin-RR by bacterium Sphingopyxis sp. USTB-05

引用

Journal of Environmental Sciences 2010年第2期22卷 168-175页

作者： Mulan Zhang Gang Pan Hai Yan State Key Laboratory of Environmental Aquatic Chemistry Research Center for Eco-Environmental Sciences Chinese Academy of Sciences Beijing 100085 China Department of Biological Science and Technology School of Applied Science University of Science and Technology Beijing Bering 100083 China

A strain, USTB-05, isolated from lake dianchi, China, degraded the cyanobacterial toxin microcystin-RR （MC-RR） at the rate of 16.7 mg/L per day. Analysis of 16S rDNA sequence showed that the strain was Sphingopyxis sp. Enzymatic degradation pathways for MC-RR by Sphingopyxis sp. USTB-05 were identified. Adda-Arg peptide bond of MC-RR was cleaved and then a hydrogen and a hydroxyl were combined onto the NH2 group of Adda and the carboxyl group of arginine to form a linear molecule as intermediate product within the first few hours. Then, through dehydration reaction, two hydrogen of amino group on arginine reacted with adjacent hydroxyl on carbon to form a linear MC-RR with two small peptide rings as the final product after 24 hr. These biodegradation pathways were different from those reported for other strains, implying that MC-RR may undergo different transformations and different products were formed due to various bacteria in natural lakes and reservoirs.

关键词： microcystin-RR biodegradation Sphingopyxis sp. USTB-05 enzymatic pathways lake dianchi

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：