Structure of the Phytoplankton Community and Its Relationship to Water Quality in Donghu Lake, Wuhan, China

The phytoplankton community structure, in terms of species composition, total standing crop,and abundance of the dominant algal species, at four stations in Donghu Lake, Wuhan, China, was investigated monthly from January 1994 to December 1996. A total of 260 taxa was observed, of which Chlorophyta (106 taxa) contributed the highest portion of the total number of taxa, followed by Bacillariophyta (82 taxa)and Cyanophyta (32 taxa). The total standing crop measured by means of chlorophyll a content, cell density,and cell biovolume, as well as the abundance of the dominant species, declined in the order of Station I to Station Ⅳ. Seasonal changes of the standing crop varied greatly among the four stations. Although the cell density at the four stations showed a single peak within a year, the peak density varied from July to November, dependent on the sampling year and the station. For chlorophyll a content and cell biovolume,multiple peaks were observed at Stations Ⅰ and Ⅱ, but a single peak was found at Stations Ⅲ and Ⅳ. The phytoplankton community structure indicated that the trophic status was the highest at Station Ⅰ (most eutrophic), followed by Station Ⅱ; Stations Ⅲ and Ⅳ were the least trophic areas. The long-term changes in phytoplankton community structure further suggested that changes in phytoplankton community structure were correlated with water quality, and eutrophication of Donghu Lake had been aggravated since the 1950s.     

Long-term changes of planktonic rotifers in a subtropical Chinese lake dominated by filter-feeding fishes

1. The long-term changes (1956–1998) in density and species composition of planktonic rotifers were studied at two sampling stations (I, II) of Lake Donghu, a shallow eutrophic Chinese Lake densely stocked with filter-feeding fishes. Annual average densities of rotifers increased with an increase in fish yield and eutrophication, whilst species number decreased from 82 in 1962–1963 to 62 in 1994–1998.
2. During 1962–98, some species such as Anuraeopsis fissa , Polyarthra spp. (including P. dolichoptera & P. vulgaris ) , Trichocerca pusilla and Synchaeta oblonga increased their percentage in abundance remarkably, whilst the proportion of Keratella cochlearis decreased at two relatively eutrophic stations from 19 to 4.2% at Station I and from 30 to 3.2% at Station II.
3. The high r _max of A. fissa probably made it more successful than other rotifers under high predation pressure by planktivorous fish. The decrease in the K. cochlearis population might be attributed partly to predation by Cyclops vicinus .
4. Small rotifers were less vulnerable to fish predation than large-sized cladocerans. Decreases in cladocerans coincided with increases in rotifers, suggesting that the indirect effect of fish predation on cladocerans might have partly contributed to the population development of rotifers in Lake Donghu during recent decades.
5. We also conducted surveys (1994–1998) of seasonal dynamics of rotifers at four sampling stations (I–IV) which have varied in trophic status after fragmentation of the lake in the 1960s. A total of 75 species were identified at the four stations. Both densities and biomass of rotifers were considerably higher in the two more eutrophic stations than in the two less eutrophic stations. This indicates that the population increase of rotifers at Stations I and II during recent decades might be partly attributed to eutrophication of the lake water.     

上海崇明岛明珠湖浮游植物群落结构

2007年1月至12月对崇明岛明珠湖的浮游植物群落结构和物种多样性的周年动态进行了初步研究.共发现浮游植物120种, 隶属于8门63属.优势种包括小席藻、微小平裂藻、旋折平裂藻、不定微囊藻和肘状针杆藻.浮游植物的年平均丰度和年平均生物量分别为5361.57×10⁴ cell·L^-1和7.68 mg·L^-1.浮游植物现存量各月间差异极显著(P<0.01),在7月达到最高峰值, 但各站点间差异不显著.浮游植物的Shannon多样性指数和Margalef指数夏秋季低, 冬春季高.生物学评价显示,明珠湖冬春两季的水质要优于夏秋两季, 且目前正处于中富营养阶段, 水体为α-中污型.典范相关分析结果表明, 影响明珠湖浮游植物群落结构的主要因子依次为温度、总磷和总氮.     

从时空异质性看东湖富营养化中原生动物的演替

1993-08～1994-08,东湖原生动物年均丰度为59,391ind./L,年均生物量为1.40mg/L。从V站到0站,随着营养水平(TSI)增加,数量(A)和生物量(B)显著增加LnA=-58.323+16.503LnTSI(n=5,r=0.983,p=0.003);LnB=-16.840+0.256TSI(n=5,r=0.996,p<0.001),两者均表现出明显的空间异质性。同时,丰度的周年动态模式也发生了明显演替,原来的春季和秋季高峰演变为冬季高峰,营养水平越高,冬季高峰越明显,随营养水平增加形成的原生动物群落结构-种类组成和现存量-的空间格局与年代变化趋势一致。     

Genetic Diversity of Plankton Community as Depicted by PCR-DGGE Fingerprinting and its Relation to Morphological Composition and Environmental Factors in Lake Donghu

To collect information about the genetic diversity of the plankton community and to study how plankton respond to environmental conditions, plankton samples were collected from five stations representing different trophic levels in a shallow, eutrophic lake (Lake Donghu), and investigated by PCR-DGGE fingerprinting. A total of 100 bands (61 of 16S rDNA bands and 39 of 18S rDNA bands) were detected. The DGGE bands unique to any single station accounted for 38% of the total bands, whereas common bands detected at all five stations accounted for only 11%. Using UPGMA clustering and MDS ordination of DGGE fingerprints, stations I and II were found to initially group together into one cluster, which was later joined by station V. Stations III and IV were isolated into two separate groups of one station each. Some differences in grouping relationships were found when analysis was completed on the basis of chemical characteristics and morphological composition, with zooplankton composition showing the greatest variability. However, the most similar stations (I and II) were always initially grouped into one cluster. Moreover, stations that exhibited the same or similar trophic level (stations III and IV), but different concentrations of heavy metals, were further differentiated by the DGGE method. Results of the present study indicated that PCR-DGGE fingerprinting was more sensitive than the traditional methods, as other studies suggested. Additionally, PCR-DGGE appears to be more appropriate for diversity characterization of the plankton community, as it is more canonical, systematic, and effective. Most importantly, fingerprinting results are more convenient for the comparative analyses between different studies. Therefore, the use of the described fingerprinting analysis may provide an operable and sensitive biomonitoring approach to identify critical, and potentially negative, stress within an aquatic ecosystem.     

Studies on phytoplankton pigments in porto novo waters (India). II. Backwater

The annual variations of phytoplankton pigments were studied from January to December, 1971 at four stations in the backwater area (Porto Novo, India). At these stations, chlorophyll a varied from 2.91–65.56 μg/1; chlorophyll b from 0–1.90 μg/l; chlorophyll c from 0–38.60 μg/1; plant carotenoids from 0.30–22.34 MSPU/m³ and phaeopigments from 0–31.51 μg/l. The main (or primary) maximum of chlorophyll a appeared during June at Stations 3–5 and at Station 6, it was during May. Stations 3 and 4 had secondary chlorphyll a maxima during September and at Stations 5 and 6 during August. In general, all the stations showed an increasing trend of chlorphyll a values before the main peak. The chlorophyll a maximum was mainly due to the presence of phytoplankton species belonging to the genera such as Noctiluca, Coscinodiscus, Thalassiothrix, Biddulphia, Hemidiscus, Melosira and Rhizosolenia. Amongst all the backwater stations, Station 5 had the highest chlorophyll a (65.56 μg/1) and the lowest chlorophyll a was recorded at Station 3. Chlorophyll a concentration was normally affected by rainfall.     

中国新记录──小金色藻在武汉东湖的季节消长

一种未曾在中国报道过的小金色藻(Chrysochromulina parva Lackey)在武汉东湖发现,此种在冬季出现,春末消失,高的种群密度(8357.6cells/ml及8737.0cells/ml)分别在1991年2月及1992年1月在水温为6─8℃时形成,持续时间近1个月,小金色藻的生物量在东湖营养状况不同的三个采集站是不同的,但季节消长的趋势基本上一致。此种喜生长在富营养的水体中。       

Long-term changes of Copepoda community (1957-1996) in a subtropical Chinese lake stocked densely with planktivorous filter-feeding silver and bighead carp

In contrast to the relatively well documented impact of particulate-feedingfish on zooplankton communities, little attention has been devotedto the impact of filter-feeding fish. Filter-feeding silverand bighead carp are the most intensively cultured fish speciesin Asia and comprise much of the production of Chinese aquaculture.However, little information is known about the impact of eitherfish on the zooplankton community. Long-term changes in theCopepoda community (1957–1996) were studied at two samplingstations of a subtropical Chinese lake (Lake Donghu) dominatedby silver and bighead carp. For both calanoids and cyclopoids,the littoral station (I) was much more resource profitable thanthe pelagic station (II). There has been a tremendous increasein the annual fish catch over the past 30 years due to the increasedstocking with fingerlings of the two carp species. There wasa notably higher fish density at Station I than at Station II.Cyclopoid abundance was notably higher at Station I than atStation II during the 1950s to the 1980s, while the reversebecame true in the 1990s. This is probably because when fishabundance increased to an extremely high level, the impact offish predation on the cyclopoids became more important thanthat of food resources at the littoral station. At both stations,cyclopoid abundance was relatively low in spite of the presenceof abundant prey. Similarly, calanoid density did not differsignificantly between the two stations in the 1950s and 1960s,but was significantly lower at Station I than at Station IIduring the 1980s and 1990s. Such changes are attributed to thegradient of fish predation between the stations and an increasingpredation pressure by the fish. The increased fish predationalso correlated with a shift in summer-dominant calanoids fromlarger species to smaller ones. In conclusion, the predaceouscyclopoids are affected by fish predation to a much lesser extentthan the herbivorous calanoids, and therefore increased predationby filter-feeding fish results in a definite increase in thecyclopoid/calanoid ratio. Predation by filter-feeding fish hasbeen a driving force in shaping the copepod community structureof Lake Donghu during the past decades.     

武汉东湖浮游植物水华的多元分析

应用多元分析中的fuzzy聚类分析、Fisher判别分析和逐步回归分析,对武汉东湖1983至1985年浮游植物水华进行一系列分析处理,得到其Ⅰ、Ⅱ两站的水华判别函数,分析了判断水华形成的主要指标:Ⅰ站为初级生产量和氨氮浓度,Ⅱ站为温度、硝酸盐浓度、叶绿素a浓度和COD,此外,本文还就Ⅰ、Ⅱ两站浮游植物的两个因子(chl a和初级生产量)分别对不同形态的营养元(氨氮、亚硝酸盐、硝酸盐、总氮、磷酸盐、总磷和硅酸盐)进行了回归分析;结果指出,现在东湖浮游植物不是以磷为限制因子而是氮限制。       

Phytoplankton structure and dynamics in Lake Sanabria and Valparaíso reservoir (NW Spain)

The aim of this work is to compare the composition and seasonality of the phytoplankton population in a natural oligotrophic lake (Lake Sanabria) and a mesotrophic reservoir (Valparaíso). Both ecosystems are located on the Tera river course (NW Spain), which runs along an area of ancient metamorphic and plutonic rocks. Some physical and chemical parameters, chlorophyll a and phytoplankton biovolume were studied from monthly samples collected at different depths during the periods 1987–1989 (Lake Sanabria) and 1991–1992 (Valparaíso). Phytoplankton biovolume and chlorophyll a concentration were about five times higher in Valparaíso than in Lake Sanabria. Species composition (and main phytoplankton groups) were different. Valparaíso was highly dominated by diatoms and Lake Sanabria by cryptophytes and small chlorophytes. In spite of the fact that both sites were nitrogen limited, heterocystous cyanophytes (Anabaena sp.) were detected only in Valparaíso. The relationships between phytoplankton structure and trophic level, hydrological conditions and nitrate content are discussed.     

Floristic studies on freshwater algae of Lake Gondwana,Northern Victoria Land (Antarctica)

Benthic algal mats and phytoplankton of Lake Gondwana (Northern Victoria Land, Antarctica) were investigated. Biomass, chlorophyll content and floristic analyses were carried out on algal mats. The mats are composed of two layers different in colour, floristic composition and chlorophyll content. The algal flora of the mats amount to 34 taxa (19 Cyanophyta, 7 Bacillariophyta, 8 Chlorophyta). The phytoplankton community is species-poor (only 5 taxa). Crytophyta account for about 98% of total algal density.     

Long-term changes in crustacean zooplankton and water quality in a shallow, eutrophic Chinese lake densely stocked with fish

From surveys made in 1962–1963, 1973–1974, 1979–1996 at two Stations in Lake Donghu, a shallow eutrophic water body near Wuhan, P. R. China, the authors, derive long-term changes in species composition, standing crop and body-size of planktonic crustaceans. The species number decreased from the 1960s to the 1990s. The cladocerans dropped from 46 (1960s) to 26 (1980s) to 13 (1990s); the copepods decreased from 14 (1960s) to 10 (1980s) to 7 (1990s). From the mid-1980s on, the dominant crustaceans also changed: Daphnia hyalina and D. carinata ssp. were replaced by Moina micrura and Diaphanosoma brachyurum at Stations 1 and 2, respectively; Cyclops vicinus replaced Mesocyclops leuckarti.Densities and biomass of Cladocera decreased markedly after 1987. Annual average densities and biomass of cladocerans were statistically differences between 1962–1986 and 1987–1996 (P > 0.01). Annual average densities of Daphnia (Station 1 + Station 2) were negatively correlated with fish yield .Since the 1980s, annual average body length of Cladocera and Calanoida decreased, while annual average body length of Cyclopoida increased. In the same years, average body length of copepods was lower during May–October than during January–April and November–December.A 12-yr data analysis showed annual average concentration of chlorophyll^-a (Chl^-a) to be negatively correlated with annual average density of Daphnia, whilst lake transparency was positively correlated with annual average densities of Daphnia. The results imply that, since Daphnia feeds efficiently on phytoplankton, it could decrease concentration of Chl^-a, and enhance water transparency.     

Acidity status and phytoplankton species richness,standing crop,and community composition in Adirondack,New York,U.S.A. lakes

The mid-summer phytoplankton communities of more than 100 Adirondack lakes ranging in pH from 4.0 to 7.2 were characterized in relation to 25 physical-chemical parameters. Phytoplankton species richness declined significantly with increasing acidity. Acidic lakes (pH < 5.0) averaged fewer than 20 species while more circumneutral waters (pH > 6.5) averaged more than 33 species. Phytoplankton abundance was not significantly correlated with any of the measured physical-chemical parameters, but standing crop parameters, i.e., chlorophyll a and phytoplankton biovolume, did correlate significantly with several parameters. Midsummer standing crop correlated best with total phosphorus concentration but acidity status affected the standing crop-phosphorus relationship. Circumneutral waters of low phosphorus content, i.e. < 10 µg·1^–1 TP, averaged 3.62 µg·1^–1 chlorophyll a whereas acidic lakes of the same phosphorus content averaged only 1.96 µg·1^–1 chlorophyll a. The midsummer chlorophyll content of lakes of high phosphorus content, i.e. > 10 µg·1^–1 TP, was not significantly affected by acidity status.Adirondack phytoplankton community composition changes with increasing acidity. The numbers of species in midsummer collections within all major taxonomic groups of algae are reduced with increasing acidity. The midsummer phytoplankton communities of acidic Adirondack lakes can generally be characterized into four broad types; 1) the depauperate clear water acid lake assemblage dominated by dinoflagellates, 2) the more diverse oligotrophic acid lake community dominated by cryptomonads, green algae, and chrysophytes, 3) the productive acid lake assemblage dominated by green algae, and 4) the chrysophyte dominated community. The major phytoplankton community types of acid lakes are associated with different levels of nutrients, aluminum concentrations, and humic influences.     

武汉东湖水网区底栖动物群落特征及其水质的生物学评价

2008年4-9月间三次对武汉东湖水网区15个水体的底栖动物进行调查,共采集到大型底栖动物50种,隶属于16科41属,其中严东湖底栖动物种数最多,有28种;北湖、青潭湖和杨春湖仅2-3种,其他水体介于以上两者之间。定量分析表明,在超富营养及富营养湖泊中,优势类群均为寡毛类和水生昆虫摇蚊科种类,只是所占比例有所差异;中营养湖泊严东湖,密度上水生昆虫占优势,为总量的59.1%,生物量上软体动物占优势,为总量的96.4%;青山港中,密度上寡毛类占优势,为总量的63.6%,生物量上软体动物占绝对优势,为总量的99.1%。采用Shannon-Weaver多样性指数(H)、Goodnight-Whitley指数(GI)及Biotic Index生物指数(BI)对东湖水网区水体及武汉周边的南北咀、肖四海的水质进行评价,结果显示BI的评价结果与湖泊现实情况基本相符,推荐Biotic Index生物指数作为东湖水网区底栖动物生物评价的指标。       

Grazer control and nutrient limitation of phytoplankton biomass in two Australian reservoirs

1. Grazer and nutrient controls of phytoplankton biomass were tested on two reservoirs of different productivity to assess the potential for zooplankton grazing to affect chlorophyll/phosphorus regression models under Australian conditions. Experiments with zooplankton and nutrients manipulated in enclosures, laboratory feeding trials, and the analysis of in-lake plankton time series were performed. 2. Enclosures with water from the more productive Lake Hume (chlorophyll a = 3–17.5 μg l^–1), revealed significant zooplankton effects on chlorophyll a in 3/6, phosphorus limitation in 4/6 and nitrogen limitation in 1/6 of experiments conducted throughout the year. Enclosures with water from the less productive Lake Dartmouth (chlorophyll a = 0.8–3.5 μg l^–1), revealed significant zooplankton effects in 5/6, phosphorus limitation in 5/6 and nitrogen limitation in 2/6 of experiments. 3. While Lake Hume enclosure manipulations of the biomass of cladocerans (Daphnia and Diaphanosoma) and large copepods (Boeckella) had negative effects, small copepods (Mesocyclops and Calamoecia) could have positive effects on chlorophyll a. 4. In Lake Hume, total phytoplankton biovolume was negatively correlated with cladoceran biomass, positively with copepod biomass and was uncorrelated with total crustacean biomass. In Lake Dartmouth, total phytoplankton biovolume was negatively correlated with cladoceran biomass, copepod biomass and total crustacean biomass. 5. In both reservoirs, temporal variation in the biomass of Daphnia carinata alone could explain more than 50% of the observed variance in total phytoplankton biovolume. 6. During a period of low phytoplankton biovolume in Lake Hume in spring–summer 1993–94, a conservative estimate of cladoceran community grazing reached a maximum of 0.80 day^–1, suggesting that Cladocera made an important contribution to the development of the observed clear-water phase. 7. Enclosure experiments predicted significant grazing when the Cladocera/Phytoplankton biomass ratio was greater than 0.1; this threshold was consistently exceeded during clear water phase in Lake Hume. 8. Crustacean length had a significant effect on individual grazing rates in bottle experiments, with large Daphnia having highest rates. In both reservoirs, mean crustacean length was negatively correlated with phytoplankton biovolume. The observed upper limit of its variation was nearly twice as high compared to other world lakes.     

Phytoplankton community and succession in a newly man-made shallow lake, Shanghai, China

We studied phytoplankton community and succession in Lake Dishui, the largest man-made coastal lake in China. The lake experienced drastic changes in physicochemical conditions since its creation in 2003. Monthly phytoplankton communities were characterized between 2006 and 2011. A two-dimensional solution of nonmetric multidimensional scaling clearly delineated four groups of distinct phytoplankton community structure. Indicator species analysis showed that Group I (2006–2008) was characterized by mainly nanoplankton including Chromulina pygmaea. Group II (2009) was characterized by nonmotile, unicellular, elongated, or filamentous taxa, which are resistant to grazing pressure due to their large size. Group III (winter–early spring since 2010) was characterized by many motile taxa. The most characteristic taxa in Group IV (summer–autumn since 2010) were the flagellate algae. Seasonal variation in phytoplankton community was highest after 2010. Changes in phytoplankton communities may closely reflect rapid changes in lake environmental conditions such as desalination and nutrient enrichment.     

武汉东湖颗粒有机碎屑现存量的测定

对武汉东湖三个采样点的颗粒有机碎屑现存量进行了测定,三个站的平均量(以dmm3/l表示)分别为72,505、18,125和52,398,其现存量与湖水的pH值无关;与水温有一定的正相关,但这种关系是间接的。       

Phytoplankton distribution along trophic gradients within and among reservoirs in Catalonia (Spain)

1. Longitudinal gradients in the epilimnetic waters of stratified reservoirs provide a useful database to study changing environmental conditions. The spatial distribution, assemblage structure and specific adaptations of phytoplankton assemblages can be analysed along these gradients over short time scales. 2. Four reservoirs with a similar typology, located along an altitudinal gradient in the same eco‐region, were sampled along their longitudinal axes. In total, 19 sampling stations provided a trophic spectrum, ranging from oligo‐mesotrophy to hypertrophy, which was quantified by calculating the trophic state index of each sampling station in the four reservoirs. 3. Several patterns in phytoplankton assemblage structure were detected. Total chlorophyll‐a (Chl‐a), biovolume, abundance and the relative biomass contribution of the main algal groups (chlorophytes, cyanobacteria, cryptophytes and diatoms) were highly correlated with their location along the trophic gradient. 4. We also adopted the functional classification of Reynolds et al. (2002) : this effectively summarized differences among phytoplankton assemblages under varying resource‐limiting combinations, especially nutrients and underwater light climate. 5. In terms of relationships with the trophic gradient, diatoms and cyanobacteria exhibited significant opposing trends in both their relative chlorophyll contribution to total Chl‐a and biovolume. Chlorophytes were more abundant at an intermediate position along the trophic spectrum. 6. The identified patterns are consistent with models of self‐organization of phytoplankton assemblages. In particular, light availability was a strong determinant of size and shape diversity, especially in hypertrophic conditions, where ‘R‐strategist’, needle shaped species, dominated the system. In contrast, under decreased availability of nutrients and higher light extinction coefficients (K_d), the system was co‐dominated by C‐ and S‐strategist species, having shapes with a higher surface/volume ratio.     

Diatoms and biomonitoring: should cell size be accounted for?

Despite the fact that biovolume calculation is a common procedure in most phytoplankton and periphyton studies, diatom community analyses are usually based on relative abundance data. In a biomonitoring context, a community metric that accounts for cell size could be of interest due to the potential differences that might exist in nutrient uptake between large and small-sized species. This paper addresses the question of whether diatom community analysis should be based on relative abundance, biovolume or cell surface. The results show that although community structure expressed as relative proportion of taxa varied according to the metric used, the ordinations conducted with each metric were similar. The explained percentage of species variance was slightly higher with the relative abundance metric compared to the metrics based on relative biovolume or cell surface area. Partial CCAs showed that each water chemistry variable generally explained a higher portion of species variance when the relative abundance was used. The analyses conducted with two size groups (small and large taxa) expressed as relative abundance and relative biovolume showed similar results. Moreover, our data showed that there is no significant relationship between diatom size and total phosphorus. According to these results, it seems that relative abundance would be the most appropriate metric to use for biomonitoring purposes. The biovolume and cell surface area calculations added substantially to the total analysis time due to the numerous measurements required, but did not improve the variance explained in community structure, and site ordinations were not significantly different. Electronic supplementary material Electronic supplementary material is available for this article at and accessible for authorised users.     

安徽沱湖夏季浮游植物群落结构特征与环境因子关系

为了揭示沱湖浮游植物群落结构特征及其与水环境因子的关系,于2016年7月(夏季),对沱湖流域上游至下游11个采样点浮游植物种类组成、细胞丰度、生物量等进行调查研究。结果显示,沱湖共有浮游植物96种(含变种),隶属8门48属,其中绿藻门(Chlorophyta)和硅藻门(Bacillariophyta)种类最多,绿藻门有23属39种,占总种数的40.63%,硅藻门有7属20种,占总种数的20.83%;其次为裸藻门(Euglenophyta),有5属17种,占总种数的17.71%,蓝藻门(Cyanophyta) 8属14种,占14.58%;甲藻门(Pyrrophyta) 2属2种,隐藻门(Cryptophyta) 1属2种,各占总种数的2.08%,黄藻门(Xanthophyta)与金藻门(Chrysophyta)均有1属1种,均占总种数的1.04%。绿藻和硅藻类物种在沱湖浮游植物群落结构中处于优势地位,沱湖夏季浮游植物种类组成表现为绿藻-硅藻型。沱湖夏季浮游植物细胞丰度与生物量从上游到下游呈逐渐增加趋势,细胞丰度与生物量平均值分别为4.022×106cells/L与3.046 mg/L,蓝藻门和绿藻门类群为沱湖浮游植物细胞丰度主体,硅藻门和裸藻门类群为沱湖浮游植物生物量的主体;上游浮游植物多样性指数与均匀度指数均略高于下游采样点,沱湖水质呈β中污型-无污染型,上游水质优于下游水质。浮游植物群落结构与水环境因子的典型对应分析(CCA)结果表明,电导率、透明度、水深及pH值等环境因子与沱湖夏季浮游植物群落结构有较强的相关性。