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1.
1 INTRODUCTION Surface blooms of nuisance cyanobacteria are often a signal of eutrophication (Jacoby et al., 2000). They are generally favored by conditions of low nitrogen to phosphorus ratios, high total phosphorus content, high water temperature, high … 相似文献
2.
Antioxidant systems are vital in life activities of macrophytes. Species with dif ferent life forms need to cope with distinct environments by modifying physiological characters, especially antioxidant systems. In order to find dif ferences among life forms and consequence of lake eutrophication, we studied three antioxidant enzymes activity(superoxide dismutase(SOD), ascorbate oxidase(APX) and catalase(CAT)) and total soluble phenolics(TP) content in leaves of 26 macrophyte species in September 2013 in Lake Erhai, China. We found that antioxidation varied accordingly with life forms. The activities of SOD and APX in emergent macrophytes(EM) and floating-leaved macrophytes(FM) were much lower than those of submerged macrophytes(SM). On the contrary, TP content was much higher in EM and FM species. There was a negative correlation between TP and antioxidant enzyme activities(CAT and APX).The results suggested that EM and FM species rely on phenolics might to adapt to adverse environments(higher herbivores predation pressure and UV radiation intensity), while SM species more rely on antioxidant enzymes possibly due to lower demand for antioxidation and/or lack of light and inorganic C availability for phenolics synthesis. We also found FM species represent highest fitness in term of antioxidant system,which would lead to overgrowth of FM species and littoral zone bogginess during lake eutrophication.Finally, it is necessary to carry out the verification experiment under the control condition in the later stage,especially for the dominant ones in eutrophic lakes, to understand the exact adaptive mechanisms of them. 相似文献
3.
Epiphytic bacterial communities on two common submerged macrophytes in Taihu Lake: diversity and host-specificity 总被引：1，自引：0，他引：1
Leaves of terrestrial and aquatic plants are home to a wide diversity of bacterial species. However, the diversity and variability of epiphytic bacteria on their submerged plant hosts remains poorly understood. We investigated the diversity and composition of epiphytic bacteria from two common submerged macrophytes: Vallisneria natans and Hydrilla verticillata in Taihu Lake, Jiangsu, China, using methods of terminal restriction fragment length polymorphisms (T-RFLP) and clone library analyses targeted at bacterial 16S rRNA genes. The results show that: (1) the libraries of the two waterweeds contain wide phylogenetic distribution of bacteria, and that the sequences of the two libraries can be separated into 93 OTUs (at 97% similar value); (2) Betaproteobacteria, including Burkholderiales, was the most abundant bacterial group on both plants. Cyanobacteria and Gammaproteobacteria were the second largest groups on V. natans and H. verticillata, respectively. Both clone libraries included some sequences related to those of methanotrophs and nitrogen-fixing bacteria; (3) Cluster analysis of the T-RFLP profiles showed two distinct clusters corresponding to the two plant populations. Both ANOSIM of the T-RFLP data and Libshuff analysis of the two clone libraries indicated a significant difference in epiphytic bacterial communities between the two plants. Therefore, the epiphytic bacterial communities on submerged macrophytes appear to be diverse and host-specific, which may aid in understanding the ecological functions of submerged macrophytes in general. 相似文献
4.
Cai Xingwei Ye Shaowen Li Wei Fan Hourui Li Zhongjie Zhang Tanglin Liu Jiashou 《中国海洋湖沼学报》2019,37(1):278-289
The knowledge of prey small fish stock, distribution and abundance is necessary to guide stocking of piscivorous fish for the biomanipulation in domestic tap water lakes. This study describes the current status of small fish community in Lake Kuilei (China), and examines the spatial and seasonal variations of the community in relation to key environmental factors. Based on submerged macrophyte cover and water depth, the lake was divided into five major habitats: (1) macrophyte covered shallow habitat of water depth < 2.00 m, (2) uncovered or less-covered shallow habitat (2.00 m–3.50 m), (3) uncovered medium shallow habitat (3.50 m–5.00 m), (4) uncovered medium deep habitat (5.00 m–6.50 m) and (5) uncovered deep habitat (6.50 m–8.50 m). The abundance and composition of small fish were monitored by benthic fykenet sampling from April 2013 to January 2014. A total of 2881 individuals belonging to 5 families and 21 species were collected. Based on their abundance (accounted for 88.96% of the total) and occurrence (more than 33.33%), Acheilognathus chankaensis, Acheilognathus macropterus, Microphysogobio microstomus, Pseudorasbora parva and Rhinogobius giurinus were recognized as dominant small fish species. The results of correlation analysis identified that species richness ( Sr ), Shannon-Wiener diversity index ( H′ ) and Margalef′s richness index ( D ) were significantly negatively correlated with water depth, but positively correlated with biomass of submerged macrophytes.Redundancy analysis (RDA) revealed that the spatial distributions of most small fishes were negatively associated with water depth. The details of these findings are beneficial to understanding the adaptation of the small fishes in degraded environments, and to developing suitable biomanipulation strategies for the management of fish resources and water quality in the lakes along the lower reach of the Changjiang (Yangtze) River basin.
相似文献5.
In aquatic ecosystems, macrophytes and phytoplankton are main primary producers, in which macrophyte plays an important role in maintaining clear water state, while phytoplankton often dominates in turbid waterbodies. In the present study, the growth and photosynthetic activity of the submerged aquatic plant Ceratophyllum oryzetorum Kom. in different cell densities of cyanobacterial bloom are studied. The results show that the plant length and fresh mass of C. oryzetorum are promoted by low cyanobacterial cell densities. Medium and high cyanobacterial cell densities, on the contrary, act as inhibitory. Furthermore, the photosynthetic activity of C. oryzetorum is strongly inhibited by high cyanobacterial cell densities. To a certain extent, the growth of cyanobacteria is inhibited by C. oryzetorum, but no significant effect is found in this study. 相似文献
6.
《中国海洋湖沼学报》2017,(2)
Freshwater shallow lakes typically exhibit two alternative stable states under certain nutrient loadings:macrophyte-dominated and phytoplankton-dominated water regimes.An ecosystem regime shift from macrophytes to phytoplankton blooming typically reduces the number of species of invertebrates and fishes and results in the homogenization of communities in freshwater lakes.We investigated how microbial biodiversity has responded to a shift of the ecosystem regime in Dianchi Lake,which was previously fully covered with submerged macrophytes but currently harbors both ecological states.We observed marked divergence in the diversity and community composition of bacterioplankton between the two regimes.Although species richness,estimated as the number of operational taxonomic units and phylogenetic diversity(PD),was higher in the phytoplankton dominated ecosystem after this shift,the dissimilarity of bacterioplankton community across space decreased.This decrease in beta diversity was accompanied by loss of planktonic bacteria unique to the macrophyte-dominated ecosystem.Mantel tests between bacterioplankton community distances and Euclidian distance of environmental parameters indicated that this reduced bacterial community differentiation primarily reflected the loss of environmental niches,particularly in the macrophyte regime.The loss of this small-scale heterogeneity in bacterial communities should be considered when assessing long-term biodiversity changes in response to ecosystem regime conversions in freshwater lakes. 相似文献
7.
Abundance and production ofBranchiura sowerbyi (Oligochaeta: Tubificidae) in two typical shallow lakes (Hubei, China) 总被引：1，自引：0，他引：1
An April 1996 to March 1997 comparative study on the abundance and secondary production ofBranchiura sowerbyi Beddard, 1892 in two typical shallow lakes showed that in Houhu, an algae-dominated lake, the worm density (68 ind·m−2) peaked in July, biomass (1.930 g·m−2) peaked in June, while in Biandantang, a macrophyte-dominated lake, standing stock (density: 60 ind·m−2; biomass: 1.019 g·m−2 in wet weight) peaked in December. Secondary production of the animal in Houhu Lake was 3.413 g wet wt m−2 a−1, a little more than that (2.675 g wet wt m−2 a−1) in Biandantang Lake. Their turnover rates (P/B ratios) were 4.0 and 5.0, respectively.
Project (39600019 and 39430101) supported by NSFC. 相似文献
8.
近百年来龙感湖地区湖泊营养化过程 总被引：5，自引：0，他引：5
由于近年来社会经济的迅速发展，湖泊富营养化问题日趋严重。其中湿地的破坏是导致人湖营养盐增加的一个重要原因。对湿地变化与湖泊营养盐状况关系的分析是制定湖泊环境整治和生态修复的重要科学依据。湖泊沉积物含有丰富的生物和理化方面的信息，在缺乏长期湖泊监测记录的情况下。可以用来重建湖泊及其流域过去变化的历史。根据龙感湖表层沉积物^210Pb活度比变化，分析了该地区近百年来沉积物中湿地花粉、总磷和磁性参数．探讨了湖泊营养化过程及机理。研究表明，龙感湖近百年来营养级的增加是与湿生植被的破坏密切相关。20世纪上半叶的湖泊富营养化响应于磁性参数指示的流域土壤侵蚀速率的增加，而20世纪70年代以来湖泊营养程度的加重则与龙感湖流域农业化肥的使用和湿地植被破坏而导致湿地功能减弱有关。龙感湖流域内人类对湖周潍地的改造．破坏了湿地植被，助长了人湖物质的增加。湖泊营养相对富集，最终导致水体富营养化发生。 相似文献
9.
The aim of this study was to evaluate the physiological responses of a submerged macrophyte to a floating fi lamentous green algal bloom in clear-water conditions.Elodea nuttallii was grown with floating Cladophora sp.at four diff erent levels(0,control;140,280,560 g FW/m ~2)in an outdoor experimental system,and its photosynthetic and antioxidant systems were evaluated.The presence of floating Cladophora sp.signifi cantly changed the water environment by decreasing light intensity and increasing dissolved oxygen and the pH value.The photosynthetic parameters of E.nuttallii(e.g.?F/F _m~￠,F _v/F _m,total chlorophyll)were higher in the presence of floating Cladophora sp.than in the control at the beginning of experiment.Because of the increasing dissolved oxygen concentration and pH value,the values of these indicators decreased(except for photosynthetic pigments)during the experiment.Compared with E.nuttallii in the control,E.nuttallii growing in the presence of floating Cladophora sp.showed higher malondialdehyde content,catalase activity,and peroxidase activity.The biomass of E.nuttallii was decreased by about 30% in the presence of high biomasses of floating Cladophora sp.(280 and 560 g FW/m ~2).These results suggest that floating Cladophora had complex eff ects on the biomass of E.nuttallii and that changes in water quality resulting from floating Cladophora sp.may be more important than its direct shading eff ect. 相似文献
10.
INTRODUCTIONMacrozoobenthos ,amajorgroupofaquaticfauna ,playsanimportantroleinthematerialcycleandenergyflowinawaterecosystem .Inrecentdecades ,interestinthebioenergeticsofthisgrouphasgrownrapidly .Aspectsofthebioenergeticsofmanybenthicfreshwaterspecieshavebeenpub lished .Owingtodifficultyinsamplecollectionandspecimenprocessing ,studiesofthebenthiccom munityhavereceivedlessattention .Withfisherydevelopmentandthelakeeutrophicationproblem ,investigationsontheecologicalfunctionofthelakecommun… 相似文献
11.
In aquatic ecosystems, macrophytes and phytoplankton are main primary producers, in which macrophyte plays an important role
in maintaining clear water state, while phytoplankton often dominates in turbid waterbodies. In the present study, the growth
and photosynthetic activity of the submerged aquatic plant Ceratophyllum oryzetorum Kom. in different cell densities of cyanobacterial bloom are studied. The results show that the plant length and fresh mass
of C. oryzetorum are promoted by low cyanobacterial cell densities. Medium and high cyanobacterial cell densities, on the contrary, act as
inhibitory. Furthermore, the photosynthetic activity of C. oryzetorum is strongly inhibited by high cyanobacterial cell densities. To a certain extent, the growth of cyanobacteria is inhibited
by C. oryzetorum, but no significant effect is found in this study.
Supported by the Innovation Project of CAS (No.KZCX2-YW-426), a Provincial Project of Hubei (No. 2006AA305A0402) and the National
Basic Research Program of China (973 Program, No. 2002CB 412306) 相似文献
12.
滇池是中国最大的高原淡水湖泊,是长江上游生态安全格局的重要组成部分。自2008年起政府在滇池湖滨带大规模退耕还草还林,以恢复滇池及其湖滨生态。湖滨带植被对滇池总磷浓度的影响是一个长期过程,需要通过遥感长时间连续监测的数据来评价。本文以滇池和滇池湖滨带为研究区,从空间分布、季节差异2个角度,结合入湖河流总磷负荷,研究2005—2018年滇池湖滨植被时空变化对滇池总磷浓度的影响。主要结论如下：① 滇池总磷浓度由湖缘向湖心逐渐降低,并且北部和南部偏高;2005—2018年,滇池总磷浓度呈现显著下降趋势;② 2011—2018年滇池总磷浓度显著减小与湖滨带植被的拦截作用密切相关;③ 2005—2018年滇池湖滨带草本和木本植物面积都显著增加,增加最剧烈的年份是2010—2011年;④ 相比于平水期和丰水期,枯水期NDVI与强影响区总磷浓度负相关关系最强,且木本植物NDVI与强影响区总磷浓度负相关性强于草本。本文利用长时间序列数据评价滇池总磷浓度与其湖滨植被的响应关系,可为滇池湖泊生态恢复提供科学依据。 相似文献
13.
《中国海洋湖沼学报》2021,(4)
With the increase in the need for flood prevention and lake resource used by humans,the construction of floodgates and sluices has changed the hydrological connection between rivers and lakes,and between adj acent lake s.In river-disconnected lake s,exploitation and use of lake re sources have resulted in water quality decline and mechanical disturbance intensification to a different degree.Of the large number of river-disconnected lakes in the middle-lower reaches of the Changjiang(Yangtze) River,the Futou Lake,and the Xiliang Lake lie close together and are,historically,directly connected,and so do Liangzi Lake and Baoan Lake.The extent of human disturbance is severe in the Futou Lake and the Baoan Lake,but relatively mild in the Xiliang Lake and Liangzi Lake.The freshwater rosette-forming submerged plant Vallisneria natans is one of the dominant species in the four lakes.Using microsatellite markers,we studied the genetic variation of V.natans subpopulations in lakes with different intensities of human disturbance and historical direct hydrological connections.Our results showed that human disturbance decreased plant density and clonal growth in V.natans,but might increase genetic and clonal diversity at a subpopulation level and enhance gene flow among subpopulations by sexual propagule movement.Under similar climatic conditions,different intensities of disturbance seem to have such a high selective potential to differentiate genetically adjacent lake populations that they outperform the forces of gene flow through historical direct hydrological interconnection,which tends to produce genetic homogeneity.Our findings imply that human disturbance has a profound effect on the evolutionary process of natural populations of submerged plants.Moreover,increased subpopulation genetic diversity can enhance resistance and resilience to environmental disturbances.To a certain degree,we could expect that disturbed populations have the possibility of re storing spontaneously if humans cease to perturb natural ecosystems in the future. 相似文献
14.
中国东北地区晚侏罗世煤盆地有内陆断陷山间(或山前)盆地和滨海山间断坳盆地两种。内陆盆地具同一演化过程;含煤地层中部深水湖泊相的上、下均含有煤层。滨海盆地另具同一发展过程;含煤性与盆地基底结构、海水进退息息相关。 相似文献
15.
滇池污染的成因及其治理新方案 总被引：9，自引：0，他引：9
本文对滇池的污染成因进行了综合分析。滇池污染是由两大因素造成的:一是水流太慢,二是污水南侵。从这两大污染因素可以找到两大对策:一是加速湖水流动,二是阻止污水南侵。基于滇池污染实际上是北部污染南部造成的,改变滇池出水口,开挖一条新河道,让滇池水倒流,滇池从原来的下游方换到上游方,城区污水不入滇池,即使进入也能让它快速从北部流出去,北部的污染负荷很容易从北部流出去,南部高水位的水位势压力阻止了北部负荷南侵,解决了滇池污染。 相似文献
16.
１ ＩＮＴＲＯＤＵＣＴＩＯＮＳｉｎｃｅｔｈｅ１９８０ｓａｓｅｒｉｅｓｏｆｒｅｓｅａｒｃｈｐｌａｎｉｎｃｌｕｄｉｎｇＩＧＢＰ（ｔｈｅＩｎｔｅｒｎａｔｉｏｎａｌＧｅｏｓｐｈｅｒｅ．ＢｉｏｓｐｈｅｒｅＰｒｏｇｒａｍｍｅ）ｈａｖｅｂｅｅｎｓｅｔｕｐ,ｏｆｔｈｅｍ,ＰＡＧＥＳ（ｔｈｅＰａｓｔＧｌｏｂａｌｃｈａｎｇｅｓ）ｉｓａｎｉｍｐｏｒｔａｎｔｃｏｒｅｐｒｏｊｅｃｔ．Ｔｈｅｎａｔｕｒｅｒｅｃｏｒｄｓｏｆｏｃｅａｎｄｅｐｏｓｉｔ,ｔｅｒｒｅｓｔｒｉａｌ（ｌｏｅｓｓ,ｌａｋｅｓａｎｄｓｗａｍｐ）ｄｅｐｏｓｉ… 相似文献
17.
Mingwu Zhang Chunbo Jiang Heqing Huang Gerald Charles Nanson Zhengbing Chen Wenyi Yao 《中国地理科学(英文版)》2017,27(4):577-588
The lateral distributions of depth-averaged velocity in open compound channels with emerged and submerged vegetated floodplains were analyzed based on the analytical solution of the depth-integrated Reynolds-Averaged Navier-Stokes equation with a term to account for the effects of vegetation. The three cases considered for open channels were two-stage rectangular channel with emerged vegetated floodplain, rectangular channel with submerged vegetated corner, and two-stage rectangular channel with submerged vegetated floodplain, respectively. To predict the depth-averaged velocity with submerged vegetated floodplains, we proposed a new method based on a two-layer approach where flow above and through the vegetation layer was described separately. Moreover, further experiments in the two-stage rectangular channel with submerged vegetated floodplain were carried out to verify the results. The analytical solutions of the cases indicated that the corresponding analytical depth-averaged velocity distributions agree well with the simulated and experimental prediction. The analytical solutions of the cases with theoretical foundation and without programming calculation were reasonable and applicable, which were more convenient than numerical simulations. The analytical solutions provided a way for future researches to solve the problems of submerged vegetation and discontinuous phenomenon of depth-averaged velocity at the stage point for compound channels. Understanding the hydraulics of flow in compound channels with vegetated floodplains is very important for supporting the management of fluvial processes. 相似文献
18.
For the purpose of fishery development, a hydrobiological investigation of Lake Chenhu was carried out in 1983 with reference
to the productivity of various food organisms as well as fish. Of the entire lake, the annual net primary production was determined
to be 27,818×106 kcal for phytoplankton, 2,898×106 kcal for macrophytes and 64,840×106 kcal for wet land vegetation. The annual secondary production chiefly from gastropods was 2,632×106 kcal. On the basis of 1981–1982 fishery data, the production of the main stocked fishes in the lake was also roughly computed.
Analysing all obtained production data, we find the energy conversion rate of food organisms to fish in the water at the present
stage is fairly low. Even in 1982, the year of better fishery management, food energy converted to plankton feeders or herbivores
was only 1.6–1.8%; energy converted to fish yield was even lower, only 0.2–0.8%. To get a potential fish output of the ecosystem,
a tentative estimation of fishery capacity of Lake Chenhu was made by using the index of food quotients and relevant conversion
factors. The theoretical fish production in the lake is estimated to be around 6,000 t and, through the improvement of fishery
management, an annual fish yield of 2,000 t can be expected. 相似文献
19.
Using multi-mesh gillnets and trawls, the fish communities in Dianshan Lake at 6 stations from Oct. 2009 to Jul. 2010 were investigated seasonally to reveal the biodiversity and its spatial and temporal distribution patterns. The long-term changes in their structural characteristics were then analyzed to identify the main infl uencing factors and several measures for lake restoration were put forward. Thirty six species, belonging to 9 family and 30 genera, were collected, amongst which, the order Cypriniformes accounted for 61.1% of the total species number. In terms of importance value, Cypriniformes was the predominant group, Coilia nasus the dominant species, while Cyprinus carpio and Rhinogobius giurinus were the subdominant taxa. The community types did not differ among stations, but between seasons. There were no significant differences between seasons and among stations in species diversity, but richness differed both spatially and seasonally. Along with the process of eutrophication and the drastic reduction of the area colonized by macrophytes from 1959 to 2009–2010, the fish diversity declined markedly, and species numbers of herbivores and piscivores declined proportionately more than those of invertivores, omnivores, and planktivores. The decline of potamophilus and river-lake migratory fish was more marked than those of sedentary, river-sea migratory, and estuarine fishes. Eutrophication concomitant with sharp reduction of macrophyte area and overfishing may be the main reasons for the decline in fish diversity in Dianshan Lake. 相似文献
20.
南四湖是南水北调东线工程的重要调蓄枢纽,目前湿地环境地质问题较多,主要表现为湿地面积变化大、水环境污染、水资源开采过度、湖区淤积严重、湖泊沼泽化、采空塌陷等,危胁着调水工程的顺利实施。针对湿地特征及问题成因,进行单元格剖分后建立了一套完整的评价体系,第一层将其分解为水环境、土壤环境、南四湖表层底泥重金属污染及南四湖湿地地质环境问题4个要素层;第二层再把湿地环境地质问题要素分解成若干个次要素,逐层评价后采用综合指数法求出指数值,将湿地地质环境质量划分为良好区、较好区、较差区。提出了划分渔业生产保护区、调整水生植物布局、定期泥沙清淤及建设人工湿地水质净化工程和人工湿地河道走廊工程等保护措施。 相似文献