Changes in the ecosystem structure and function of a cyanobacteria bloom-dominated,shallow lake after tenyear eutrophication management

Large and shallow lakes are widely influenced by multiple anthropogenic stressors,including eutrophication.Normally,diverse strategies of eutrophication management are needed to restore the lake ecosystems.Dianchi Lake,a subtropical plateau lake in Yunnan Province,SW China,has long experienced the effects of eutrophication and cyanobacterial blooms.To mitigate the eutrophication of Dianchi Lake,various efforts have been implemented since 2000,including reducing nutrient inputs,reestablishing aquatic macrophytes in lakeside zones,manipulating fishes and so on.However,little is known about the changes in its ecosystem structure and function after long-term efforts of eutrophication management in the lake.Therefore,this study on such changes was conducted by comparing the field data-based Ecopath models between 2009 and 2019,a decade marked by a rapid implementation of eutrophication management policies.Results show that both top-down and bottom-up processes have influenced the ecosystem structure and function.First,over this decade,nutrient reduction significantly reduced phytoplankton biomass by 49.4%.Nutrient recycling and path length in food web began to decrease,as indicated by the decrease of Finn's cycling index and Finn's mean path length.Secondly,fishing management strategy has greatly changed the composition of fish assemblage,which was dominated by the small zooplantivorous fishes with ecological niche overlapping with shrimps.In general,the stability of the ecosystem has been decreasing,due to the dramatic decrease in zooplankton biomass(83.67%)and hence a collapse of the microbial loop in the food web.Therefore,we strongly advocate the persistent efforts to mitigate the risk of recurrent cyanobacteria blooms in Dianchi Lake,necessitating stricter regulation of nutrient levels and implementing effective fish population management techniques.

Salinization-Desalinization (SDS) Processes—A Linkage between Hula Valley and Lake Kinneret Ecosystem Management

The salinization process resulted in agricultural damage in the Hula Valley and water quality deterioration in Lake Kinneret. Therefore, salinization-desalinization (SDS) processes have been emphasized in the last two decades. Global and regional extreme climatological events and water scarcity strengthen the link between Hula Valley and Lake Kinneret management design. A bond between optimizing Hula agricultural maintenance and Kinneret water quality protection is conclusively suggested. Saline contribution originated from the southern Hula Valley region to the underground and surface water is higher than from the northern organic soil. The impact of eastern water Intrusion from the Golan Heights as surface waters, river discharge and underground seepage into the Hula Valley represent north-south gradient enhancement. Salinized surface water contribution from the Hula Valley to Lake Kinneret is unwanted because presently Kinneret desalinization management policy is critically required. The present salinization of surface and underground water in the Hula Valley indicates the upper limit suitable for agricultural crop optimization and the decline of salinity is crucial. Enhancement of the portion of Jordan water within the total balance in the valley is beneficial for Hula agricultural crops but serves as a disadvantage to Kinneret desalinization implementation. Therefore, the enhancement of lake water exchange is recommended.

Research of Informatization Demands of New Countryside in Poyang Lake Ecological Economic Zone and Related Countermeasures

[Objective] The aim was to survey and analyze informatization demand in new countryside in Poyang Lake Ecological Economic Zone and to propose counter- measures, [Method] A questionnaire was made among farmers on informatization de- mands in different regions in Poyang Lake Ecological Economic Zone and the re- sults were analyzed to propose countermeasures promoting informatization. [Result] With strengthening of information awareness, information demands in rural areas in Poyang Lake Ecological Economic Zone change as follows： Information demand car- rier changes from traditional media to modern media; demand on information content changes from one-way to diversified one; demand of information service changes from one-way transmission to interaction and exchange. However, some problems still exist in informatization process, such as poor infrastructure, dispersed information resources, higher information expense and shortage of information-based talents. Hence, the countermeasures were proposed, as follows： Rational security systems should be established; financing should be as diversified as possible; informatization infrastructure should be reinforced; agricultural economic information and informatiza- tion service system should be established. [Conclusion] The research lays foundation for construction of informatization in new countryside in Poyang Lake Ecological Economic Zone.

Reading man皮瓣修复术治疗皮肤缺损的疗效观察

目的:探讨Reading man皮瓣修复术在全身不同部位皮肤缺损及其预防瘢痕增生的临床疗效。方法:回顾性分析2021年1月—2023年10月该科应用Reading man皮瓣修复术治疗全身不同部位皮肤软组织缺损的20例患者临床资料。结果:所有患者皮瓣均成活。术后随访时间为3~24个月,所有皮瓣血运良好,色泽红润,质地柔软,外观适宜,局部皮肤张力较低,手术切口瘢痕增生不明显,切口周围软组织无明显形变,周围关节活动度正常。所有患者均恢复良好,疗效满意。结论:Reading man皮瓣特有的设计可以很好地解决全身多部位较大的皮肤软组织缺损,尤其在术中可以最大限度地减少正常皮肤的切除,术后外观、功能及皮肤瘢痕增生均有较满意的表现,且不存在自体皮移植带来的供皮区损伤。

牛冠状病毒TaqMan荧光定量PCR检测方法的建立及应用

为建立牛冠状病毒TaqMan荧光定量PCR检测方法,根据GenBank收录的牛冠状病毒AKS-01株N基因序列(KU886219)保守区设计特异性引物和探针,构建重组质粒并进行反应条件优化、特异性试验、重复性试验以及敏感性试验,建立一种检测BCoV的TaqMan荧光定量PCR方法。结果显示,建立的牛冠状病毒TaqMan荧光定量PCR检测方法特异性、敏感性和重复性均良好。该方法BCoV重组质粒标准品在5.75×10^(7)~5.75×10^(3)copies/μL时与Ct值呈现良好线性关系,该方法对牛轮状病毒、牛传染性鼻气管炎病毒、牛病毒性腹泻病毒、牛副流感病毒3型均无交叉反应,特异性良好;该方法对BCoV重组质粒标准品最低检测限为5.75×10^(1)copies/μL;批内和批间重复性试验结果稳定,变异系数均小于2%。利用所建立的TaqMan荧光定量PCR方法对收集的132份样品进行检测,与常规PCR相比,两者符合率为96.21%,可为BCoV的临床检测和流行病学调查提供技术支持。

Human impact recorded in the sediment of Honghu Lake, Hubei, China

Vertical profiles of the total organic carbon （TOC）, total nitrogen （TN）, phosphorus, susceptibilities, elements and partical size were analyzed in a short ^137Cs-dated sediment core collected from Honghu Lake, China. The average sedimentation rate was 1.55 mm/a. The results indicated that trophic status of Honghu Lake in the historical period had experienced three stages. Before 1840 the lake was characterized with lower productivity, TOC was less than 9.92 g/kg; TN was 0.902 to 1.24 g/kg. During about 1840-1950, population increased quickly, there was an obvious change in TOC with an average of 13.0 g/kg. Since 1950, human impacts have accelerated the lake eutrophication and nutrients enriched in the sediment with TOC of 21.7 to 93.1 g/kg, TN of 1.77 to 8.78 g/kg. The heavy metal concentration profiles presented similar distribution trends except Pb .and Mn. The results from elements analyses indicated that Honghu Lake had not been polluted by heavy metals except lead.

Ecological and environmental water demand of the lakes in the Haihe-Luanhe Basin of North China

The purpose of this paper is to present a brief concept of the ecological and environmental water demand of lake. The present situation and affecting factors of lake ecological system in the Haihe\|Luanhe Basin of North China was analyzed. The calculating method of the ecological and environmental water demand of the lake basis on the water body and the calculating method of the ecological and environmental water demand of the lake basis on the aquatic ecosystem, wetland and vegetation were compared and discussed. As the examples of Baiyangdian Lake and Beidagang Lake in Haihe\|Luanhe river basin, the ecological and environmental water demand of the two lakes was calculated to be 27×10\+8m\+3. It is 6.75 times to the water demand according to the calculating method of the ecological and environmental water demand of the lake basis on the water body. The research result indicated: (1) The calculating methods of the ecological and environmental water demand of the lake basis on the aquatic ecosystem should be better than only basis on the water body of lake. (2) The data, such as area of the vegetation kind around and in the lake, the vegetation coefficient, the evaporating amount of the vegetation and the vegetation water demand itself around and in the lake are lack and urgent need. Some suggestions for controlling and regulating the water resource of the lake in North China were proposed.

Flood management of Dongting Lake after operation of Three Gorges Dam

Full operation of the Three Gorges Dam(TGD) reduces flood risk of the middle and lower parts of the Yangtze River Basin. However,Dongting Lake, which is located in the Yangtze River Basin, is still at high risk for potentially severe flooding in the future. The effects of the TGD on flood processes were investigated using a hydrodynamic model. The 1998 and 2010 flood events before and after the operation of the TGD, respectively, were analyzed. The numerical results show that the operation of the TGD changes flood processes, including the timing and magnitude of flood peaks in Dongting Lake. The TGD can effectively reduce the flood level in Dongting Lake, which is mainly caused by the flood water from the upper reach of the Yangtze River. This is not the case, however, for floods mainly induced by flood water from four main rivers in the catchment. In view of this, a comprehensive strategy for flood management in Dongting Lake is required. Non-engineering measures, such as warning systems and combined operation of the TGD and other reservoirs in the catchment, as well as traditional engineering measures, should be further improved. Meanwhile, a sustainable philosophy for flood control, including natural flood management and lake restoration, is recommended to reduce the flood risk.

A Historical Sedimentary Record of Mercury in a Shallow Eutrophic Lake: Impacts of Human Activities and Climate Change

Mercury and its derivatives are hazardous environmental pollutants and could affect the aquatic ecosystems and human health by biomagnification. Lake sediments can provide important historical information regarding changes in pollution levels and thus trace anthropogenic or natural influences. This research investigates the 100-year history of mercury (Hg) deposition in sediments from Chao Lake, a shallow eutrophic lake in China. The results indicate that the Hg deposition history can be separated into three stages (pre-1960s, 1960s–1980s, and post-1980s) over the last 100 years. Before the 1960s, Hg concentrations in the sediment cores varied little and had no spatial difference. Since the 1960s, the concentration of Hg began to increase gradually, and showed a higher concentration of contamination in the western half of the lake region than in the eastern half of the lake region due to all kinds of centralized human-input sources. The influences of anthropogenic factors and hydrological change are revealed by analyzing correlations between Hg and heavy metals (Fe, Co, Cr, Cu, Mn, Pb, and Zn), stable carbon and nitrogen isotopes (d13C and d15N), nutrients, particle sizes, and meteorological factors. The results show that Hg pollution intensified after the 1960s, mainly due to hydrological change, rapid regional development and urbanization, and the proliferation of anthropogenic Hg sources. Furthermore, the temperature, wind speed, and evaporation are found to interactively influence the environmental behaviors and environmental fate of Hg.

盐湖卤水中硼酸盐化学形态及Raman光谱定量分析

我国青藏盐湖以富含硼锂而著称,卤水中硼化学赋存状态随湖水化学类型的不同而发生变化,其中以硫酸盐型盐湖卤水中硼酸盐的存在形式变化最为复杂,卤水蒸发过程一般不以固体盐形式结晶析出,而是以多硼物种形式富集于氯化镁饱和老卤中,表现出严重的过饱和性,对后续锂盐和镁盐的分离提取影响较大。开展盐湖卤水体系中硼酸盐化学形态、分布规律及离子间作用机制等溶液化学研究对盐湖资源高效开发具有重要的意义。相比常规拉曼光谱技术,拉曼积分球基于拉曼散射原理可极大地提高激发光的使用效率和拉曼散射信号,对硼酸盐溶液结构检测具有拉曼响应信号强、检出限低、信噪比高等优点,为盐卤复杂体系硼酸盐化学形态的定量分析奠定了基础。利用拉曼积分球开展了盐湖卤水硼酸盐化学形态研究,阐述了卤水蒸发过程多硼酸根离子的变化规律;同时借助响应曲面法进行实验设计与优化,建立了共存盐类干扰回归模型用于盐湖卤水中单硼物种B(OH)_(3)的准确测定。结果表明,盐湖卤水浓缩过程中硼不断聚合生成多聚度硼酸根离子如B_(3)O_(3)(OH)_(4)^(-)和B_(6)O_(7)(OH)_(7)^(2-)等,硼的化学形态变化规律与碱土金属如MgCl_(2)-MgO-2B_(2)O_(3)-H_(2)O体系中硼物种变化一致,但与碱金属溶液体系物种变化差别较大。回归模型对卤水中正硼酸B(OH)_(3)定量分析的相对误差小于5%,准确度较高;阐明了蒸发浓缩过程中B(OH)_(3)物种分布的变化规律,从定量视角初步阐述了卤水富集过程硼酸根离子间的聚合作用关系,可为后续开展盐卤体系多硼物种分布及作用机制研究提供新思路、新方法。

Impact assessment of climate change and human activities on annual highest water level of Taihu Lake

The annual highest water level of Taihu Lake （Zm） is very significant for flood management in the Taihu Basin. This paper first describes the inter-annual and intra-annual traits of Zm from 1956 to 2000. Then, using the Mann-Kenall （MK） and Spearman （SP） nonparametric tests, the long-term change trends of area precipitation and pan evaporation in the Taihu Basin are determined. Meanwhile, using the Morlet wavelet transformation, the fluctuation patterns and change points of precipitation and pan evaporation are analyzed. Also, human activities in the Taihu Basin are described, including land use change and hydraulic project construction. Finally, the relationship between Zm, the water level of Taihu Lake 30 days prior to the day of Zm （Z0）, and the 30-day total precipitation and pan evaporation prior to the day of Zm （P and E0, respectively） is described based on multi-linear regression equations. The relative influence of climate change and human activities on the change of Zm is quantitatively ascertained. The results demonstrate that： （1） Zm was distinctly higher during the 1980-2000 period than during the 1956-1979 period, and the 30 days prior to the day of Zm are the key phase influencing Zm every year; （2） P increased significantly at a confidence level of 95% during the 1956-2000 period, while the reverse was true for E0; （3） The relationship between Zm, P and E0 distinctly changed after 1980; （4） Climate change and human activities together caused frequent occurrences of high Zm after 1980; （5） Climate change caused a substantially greater Zm difference between the 1956-1979 and 1980-2000 periods than human activities. Climate change, as represented by P and E0, was the dominant factor raising Zm, with a relative influence ratio of 83.6%, while human activities had a smaller influence ratio of 16.4%.

Effects of climate change and human activity on lake shrinkage in Gonghe Basin of northeastern Tibetan Plateau during the past 60 years

Changes in the status of freshwater resources are a topic of major global, regional and local concern. This is especially so in the arid and semi-arid regions of China, where shortage of water resources plays a crucial role in limiting sustainable socioeconomic development, as well as in sustaining natural ecosystems. Recent climate change, as well as the effects of localized human activity, such as the use of water for irrigation agriculture, may have significant effects on the status of the water resources in the region. Here, we report the results of a study of changes in the areas of lakes in Gonghe Basin, northeastern Tibetan Plateau of China, over the last 60 years. The data were acquired from optical satellite images and demonstrate that the total water area of lakes in Gonghe Basin decreased significantly from the 1950s to 1980s. The cause is ascribed mainly to human activity including exploitation of farmland, against a background of increasing population; in addition, climatic data for the region demonstrate a minor drying trend during this period as the temperature increased slightly. After the construction of several reservoirs, significant amounts of water were redistributed to promote irrigation agriculture and we conclude that this caused a significant shrinkage of the natural lakes. However, both the area of farmland and the population size remained approximately constant after 1990. We conclude that the variation of the total area of lakes during the second period was mainly controlled by climatic factors （precipitation and temperature）. As the regional temperature reached a new high, the area of some of the lakes decreased sharply before finally maintaining a relatively steady state. We emphasize that anthropogenic climate change and human activity have both significantly influenced the status of water resources in the arid and semi-arid regions of China.

Characterization of Water Quality in Xiao Xingkai Lake:Implications for Trophic Status and Management

Increasing cases of lake eutrophication globally have raised concerns among stakeholders,and particularly in China.Evaluating the causes of eutrophication in waterways is essential for effective pollution prevention and control.Xiao Xingkai Lake is part of and connected to Xingkai(Khanka)Lake,a boundary lake between China and Russia.In this study,we investigated the spatio-temporal variabilities in water quality(i.e.,dissolved oxygen(DO),total nitrogen(TN),total phosphorus(TP),chemical oxygen demand(CODMn)and ammonium-nitrogen(NH4+-N))in Xiao Xingkai Lake,from 2012 to 2014,after which a Trophic Level Index was used to evaluate trophic status,in addition to the factors influencing water quality variation in the lake.The DO,TN,TP,CODMn and NH4+-N concentrations were 0.44-15.57,0.16-5.11,0.01-0.45,0.16-48.31,and 0.19-0.78 mg/L,respectively.Compared to the Environmental Quality Standards for surface water(GB 3838-2002)in China,the lake transitioned to an oligotrophic status in 2013 and 2014 from a mesotrophic status in 2012,TN and TP concentrations were the key factors influencing water quality of Xiao Xingkai Lake.Non-para-metric test results showed that sampling time and sites had significant effects on water quality.Water quality was worse in summer and in tourism and aquaculture areas,followed by agricultural drainage areas.Furthermore,lake water trophic status fluctuated between medium eutrophic and light eutrophic status from September 2012 to September 2014,and was negatively correlated with water level.Water quality in tourism and aquaculture sites were medium eutrophic,while in agricultural areas were light eutrophic.According to the results,high water-level fluctuations and anthropogenic activities were the key factor driving variability in physicochemical parameters associated with water quality in Xiao Xingkai Lake.

大口黑鲈弹状病毒Taq Man荧光定量PCR检测方法的建立及初步应用

为建立快速、敏感的大口黑鲈弹状病毒(MSRV)流行株Taq Man荧光定量PCR (qPCR)方法,本研究采用NCBI分析MSRV流行株N基因的保守序列,设计特异性引物和Taq Man探针,以构建的并经PCR和测序鉴定正确的重组质粒标准品p MD18-MSRV-N为模板,通过优化各反应条件初步建立MSRV的Taq Man q PCR检测方法。结果显示,建立的Taq Man q PCR方法标准曲线的R2为0.9906,质粒标准品在6.79×10^(8)拷贝/μL~6.79×10^(2)拷贝/μL范围内与Ct值均存在较好的线性关系。采用该方法检测MSRV及相关病毒,评估该方法的特异性,结果显示,该方法可以特异性检测MSRV,而草鱼出血病病毒、神经坏死病毒、鲤春病毒血症病毒、大口黑鲈双RNA病毒、鳜蛙虹彩病毒、传染性脾肾坏死病毒、石斑鱼虹彩病毒、大口黑鲈蛙虹彩病毒等8种常见鱼类病毒检测结果均为阴性;采用建立的方法检测不同浓度的质粒标准品(6.79×10^(8)拷贝/μL~6.79×10^(1)拷贝/μL),评估该方法的敏感性,结果显示,该方法的检测限为6.79×10^(2)拷贝/μL,比文献中的常规PCR方法敏感1 000倍;以不同批次或同一批次提取的不同浓度的质粒标准品作为模板,分别利用该方法检测,评估该方法的重复性,结果显示,该方法批内和批间重复性试验的变异系数均小于2%。采用该方法和文献中的常规PCR同时检测71份临床发病的大口黑鲈、鳜鱼、鲮鱼组织样品,结果显示阳性率为16.9%(12/71),阴性率为83.1%(59/71),且阳性样品均是从发病大口黑鲈的组织样品中检测到,而发病的鳜鱼、鲮鱼组织样品中均未检测到该病毒;常规PCR方法的阳性率为9.9%(7/71),阴性率为90.1%(64/71),二者的总符合率为93.0%。本研究建立的MSRV Taq Man q PCR方法特异性强、敏感性高、重复性和准确性均较好,可用于大口黑鲈临床样品的检测,为MSRV的快速检测提供了可行的技术手段。

Tectonic geomorphological characteristics for evolution of the Manas Lake

Owing to global climatic changes and human activities,the lakes have changed dramatically in the Junggar Basin of Xinjiang in recent 50 years. Based on the remote sensing images from Beijing Satellite No.1 in 2006 together with the measured topographical data in 1999 and other data since the 1950s,this paper analyzes mainly the features of landforms around the Manas Lake and the changes of feeding sources of the lake. The results are as follows:(1) Tectonic movement brought about the fundamental geomorphological basis for lacustrine evolution,and the Manas Lake is one of small lakes broken up from the Old Manas Lake due to tectonic movement and drought climate; the Manas Lake had existed before the Manas River flowed into it in 1915. The geomorphologic evidences for evolution of the Manas Lake include:(a) Diluvial fans and old channels at the north of the lake indicate that the rivers originating from the north mountains of the Junggar Basin had fed the Old Manas Lake and now still feed the lake as seasonal rivers; (b) The Old Manas Lake was fed by many rivers originating from the mountains,except for the Manas River,from the evidence of small lakes around the Manas Lake,old channels,alluvial fans,etc.; (c) The elevations of the alluvial and diluvial fans are near to the 280 m a.s.l. and all of the small lakes and lacustrine plains are within the range of the 280 m a.s.l.,which may prove that the elevation of the Old Manas Lake was about 280 m a.s.l.; (d) Core analysis of the Manas Lake area also indicates that the Manas Lake has existed since Late Pleistocene epoch. (2) Analysis on the feeding relations between the lakes and the lacustrine evolution shows that human activities are one of main driving forces of the lacustrine evolution in recent 50 years,and it is the precondition of restoring and maintaining the lacutrine wetlands in the study area to satisfy the feeding of the Baiyang and Manas rivers to the Manas Lake.

Shrinking and Drying up of Baiyangdian Lake Wetland:A Natural or Human Cause?

The shrinking and drying up of wetlands in arid and semiarid areas of China have been widely observed in the recent years, but there has been no consensus on whether the aggravation is caused by human activities or by global climate warming. For a better understanding of the cause, this study investigates the dynamic changes of Baiyangdian Lake wetland over the last 40 years. It is shown that since the 1980s, Baiyangdian Lake has suffered from an insufficient water input and shrunk considerably. By using SPSS 11.0, this study urines a detailed Analysis on the signifficance of the effects of the possible driving factors for the degradation. It is identified that the North China Plain has been warrnin~ up significantly in recent years, which causes a significant reduction in the precipitation and inflow to the lake. Although human disturbances such as the irrigation and storage of water in reservoirs do not play a decisive role, they accelerate the degradation and their effects should be minimized.

Recreational Use of Acidic Pit Lakes—Human Health Considerations for Post Closure Planning

Pit lakes may form in mining voids that extend below groundwater level after mining ceases and many have been found to have elevated metals concentrations and low pH through acidic and metalliferous drainage (AMD). Pit lakes are often used for recreational activities including swimming, fishing and boating and poor water quality may present health risks to recreational users. Pit lakes also provide the opportunity for additional water resource uses. The Collie Coal Basin in south-western Australia currently has a number of pit lakes with moderate AMD effects which are also used for recreational pursuits. Twelve hundred questionnaires were mailed to selected addresses in the Collie shire with an additional 170 questionnaires to specific interest groups. Participants were asked about the type of activity, frequency and duration and any health symptoms experienced after use of the lakes. Two hundred and fifty questionnaires were returned, which comprised 176 returns from the random sample and 74 from the targeted sample. Three pit lakes with elevated metals concentrations and low pH were used for recreational purposes by 62% of respondents. This was mostly in summer with swimming the most common activity. Of all respondents 52% were concerned about lake water quality and 38% using the lakes reported a variety of symptoms. Recreational use of Collie pit lakes did not represent a health risk for most of the surveyed population due to the low frequency and duration of use, however health risks may be elevated in sensitive users such as children and those consuming seafood from the lakes. Comprehensive water quality monitoring for chemicals and further characterisation of recreational use of pit lakes is warranted to more comprehensively assess the potential health risks to recreational users. Post closure mine plans need to consider potential future community uses combined with assessments of water quality and physical characteristics to reduce the potential for adverse health and safety impacts.

Impact of Drain Effluent on Surficial Sediments in the Mediterranean Coastal Wetland: Sedimentological Characteristics and Metal Pollution Status at Lake Manzala, Egypt

Surface sediments were collected from Lake Manzala, the Mediterranean coastal wetland located to the east of the Nile Delta, Egypt, to assess the effect of drain effluent on the spatial variations of sedimentary characteristics and heavy metal pollution. Grain-size compositions, textures, and heavy metal distribution patterns in sediments are presented using GIS technique. Results of the analysis of the sediment showed a clear effect of drain effluent, with an increase in fine fractions and homogeneous suspensions in transportation mode. Lake sediments were dominated by sandy mud textures, and mode of transportation was homogeneous sus- pension and rolling. Spatial distribution of heavy metals (Fe, Mn, Zn, Cu, Ni, Cr, and Pb) was studied in the lake’s surficial sediments, along with their relationship to drain effluent and their contamination status in the ecological system. Heavy metal pollution status was assessed by means of accepted sediment quality guidelines and contamination assessment methods (contamination factor, con- tamination degree, modified contamination degree, geo-accumulation, and enrichment factor). Among the determined heavy metals, Pb had the most ecological risk. Generally, the heavy metals in the surface sediments indicated pollution risk ranging from moderate to considerable, particularly, in those sites facing drains and inlets that had the highest toxic effluent. The results were interpreted by statistical means. A cluster analysis defined areas facing drain discharge and inlets as separated groups. ANOVA indicated that most of the sedimentation and studied metals directed this clustering.

General Thinkingon the Management of Blue Algae Outbreak in the Taihu Lake,the Chaohu Lake and the Dianchi Lake

Among the Chinese lakes with the problem of eutrophication, the Taihu Lake, the Chaohu Lake and the Dianchi Lake have the worst cases of blue algae outbreak, which happen every year. Other lakes also have problems of blue algae outbreak at various degrees. However, some lakes don＇t have such problems. Practices have shown that through comprehensive management, the problem can be basically eliminated or significantly alleviated. ＂Water bloom＂ and blue algae outbreak have different connotation. The major factors affecting blue algae outbreak are sources of pollutants and ecological environment. Experiences are summed up and a new thinking on its management is developed： resolving the problem of blue algae is fundamental to lake management and development goals should be clearly set forth so as to eventually build a healthy aquatic ecosys- tem. The problem of blue algae can＇t be fully tackled by solely relying on the management of eutrophication but only by combining efforts of reducing the amount of blue algae and the management of eutrophication. The number of reduced blue algae should be larger than that of naturally prolifera- ted algae so as to alleviate and eliminate the problem of blue algae outbreak. Various engineering and technical measures and relevant protective procedures should be carried out in a scientific and proper manner. The total amount of nitrogen and phosphorous entering the lake either from point-source or non-point source pollution should be substantially reduced. Controlling the source of pollution and intercepting pollutants are the bas- ic measures. Wastewater treatment plant is the largest point source pollution in the future and adequate plants should be built with improved emission standards. Meanwhile, other measures including fishing out blue algae, diverting water, dredging, ecological restoration and expanding reed zone, should be implemented to alleviate the problem of eutrophication and eventually eliminate the problem of blue algae outbreak.

The alternative saline lake ecosystem states and adaptive environmental management

Our sustainable environmental management must be based on adequate ecological concepts. The question arises: what concept is better to use for understanding and management of ecosystems? To look for an answer, we concentrate our attention on saline lakes. Every ecosystem has several alternative stable states and may demonstrate regime shifts, which are large, abrupt, persistent changes in the structure and function of a system. To understand the dynamics of ecosystems the Concept of Multiplicity of Ecosystem Alternative Stable States as a new ecological paradigm has been developed recently. The author analyzes the emerging paradigm using the case of saline lakes, and discusses how to base our adaptive environmental management on the developing paradigm. Different issues of development of the concept and its application to salinology as a scientific basis of an integrated management of a saline lake and its watershed are discussed. The concept may serve as one of the key theoretical elements of the scientific basis in sustainable environmental management.