Associations of testate rhizopods (Protozoa) in the plankton of a Malaysian estuary and two nearby ponds

Plankton samples were collected from the Chukai-Kemaman estuary in Malaysia in order to determine the distribution of testate rhizopods in relation to salinity. Two nearby freshwater ponds were sampled for comparison.
In the ponds, 35 species of testate rhizopods were found, 13 of which were not found in the estuary. From the estuary 53 species were found, of which 31 were not found in the ponds. Some species appeared to have been lifted into the plankton by the rising tide. At a generic level, the Arcella species were very similar in both ponds and estuary (Sorensen Index 80), the Difflugia species were moderately similar (Sorensen Index 47), while Nebela and Quadrullela were present in the estuarine samples, but absent from the pond samples.
The salinity gradient ranged from sea water down to a conductivity of 27 μS. All the estuarine stations were tidal. The first freshwater testate rhizopods were found in a region where the conductivity was between 3000 and 4000 μS at high tide. Where the conductivity was below 1000 μS at high tide the number of species rapidly increased, and reached a maximum of 25 in the samples from the lowest conductivities. The flowering tree, Hibiscus tiliaceus , appears to be an indicator of the region where the first freshwater testate rhizopods might be encountered upstream from the sea.     

Fish assemblage structure in an estuary of the Atlantic Forest biodiversity hotspot (southern Brazil)

We described the fish assemblage in the estuary of the Guaraguaçu River (one of the largest tributaries of the Paranaguá Bay Estuary, located within Brazil’s Atlantic Forest Biosphere Reserve) from June 2005 to May 2006, and assessed the seasonal and spatial effects of abiotic environmental attributes on the fish assemblage structure. Despite some oscillations in salinity, the upper and lower estuaries had year-round persistent oligohaline and polyhaline conditions, respectively. Despite high species richness (55 species), the Guaraguaçu River Estuary fish community contains a few dominant taxa; 11% of the richness accounts for >60% of its density and biomass. The most abundant species (in terms of both biomass and density) was Atherinella brasiliensis. Species whose densities were most strongly associated with the upper estuary were Centropomus parallelus, Ctenogobius schufeldti, Eucinostomus melanopterus, Platanichthys platana, Trinectes paulistanus, and Eugerres brasilianus. Those whose densities were most strongly associated with the lower estuary were A. brasiliensis, Sphoeroides greeleyi, Eucinostomus argenteus, Sphoeroides testudineus, Diapterus rhombeus, and Harengula clupeola. Throughout the year, canonical correspondence analysis identified: (1) the pattern of horizontal stratification of salinity along the river as being the most important variable for explaining most of the fish fauna structure; and (2) a strong relationship between the fish fauna and the salinity gradient along the estuary. Analysis of similarity further confirmed that each estuarine zone supports a year-round persistent and relatively homogeneous fish species assemblage. Total mean density and biomass remained constant over time in each estuarine habitat, but density shifted in the most abundant species, which appears related to recruitment patterns. Such species and abundance persistence likely occurs because seasonal rainfall-induced changes in river discharge are not sufficient to significantly shift runoff and salinity and thus fish assemblage structure (species composition, density and biomass) along the estuary. Such a lack of seasonal fish fauna movement as a response to changes in river flow contrasts with other estuarine systems around the world.     

Seasonal composition and spatial distribution of hyperbenthic communities along estuarine gradients in the Westerschelde

The hyperbenthic fauna of the Westerschelde estuary was sampled in spring, summer and winter of 1990 at 14 stations along the salinity gradient. Mysids dominated the hyperbenthos in each season. Other important species, either permanently (e.g. amphipods and isopods) or temporarily (e.g. fish larvae and decapod larvae) hyperbenthic, belong to a variety of faunistic groups. Spatial structure was stable through time: the estuary could be divided in the same geographically defined zones in each season. Each zone had a characteristic fauna. Gradients in salinity, dissolved oxygen and turbidity correlated strongly with the observed variation in community structure. The spatial patterns dominated over the temporal patterns, especially in the brackish part of the estuary. In the marine part, seasonal differences in the communities were more pronounced due to the occurrence of a series of temporary hyperbenthic species in spring and summer. In each season, the upstream (brackish) communities were characterized by few species occurring in very high numbers, whereas the downstream (marine) communities were composed of many species but at lower densities.     

Comparative study of the hyperbenthos of three European estuaries

The hyperbenthic fauna of the subtidal channels of the Eems (N. Netherlands), Westerschelde (S.W. Netherlands), and Gironde (S.W. France) estuaries was sampled within a 15-day period in summer 1991. In each estuary, quantitative samples were taken at regularly spaced stations covering the entire salinity gradient from marine conditions at the mouth to nearly freshwater conditions upstream. The diversity of the samples and the distribution of the species along the main estuarine gradients were assessed. Hyperbenthic communities were identified using different multivariate statistical techniques. The species composition and the density and biomass of the dominant species of each community were compared among communities.     

Structure,growth and production of a remarkably abundant population of the common goby,Pomatoschistus microps (Actinopterygii: Gobiidae)

The common goby, Pomatoschistus microps, is a relevant species from estuarine food webs, playing important roles as predator of polychaetes and crustaceans and as prey for larger fishes and crustaceans. The Minho estuary (NW Portugal) is a relatively well-preserved and productive system. To assess the population structure and production of P. microps in this estuary, monthly samples were undertaken in three different areas along an estuarine gradient in the lower estuary. The density of P. microps varied considerably among seasons and sampling stations, with higher densities occurring in summer and autumn. The lowest densities were found closer to the sea. In general, the density of females was higher than the density of males in all sampling stations, while juveniles were more abundant within a salt marsh area. Compared with other European estuaries, our data showed a remarkable higher density and production values of P. microps. This may be related to the high freshwater input and the low salinities found in this estuary. In addition, we hypothesize that the lower density of the sympatric species P. minutus and the high availability of bivalve shells observed in the Minho estuary may have also contributed to the present results, once P. minutus and P. microps often display a diet overlap and the bivalve shells are crucial for the common goby reproduction.     

The influence of seasonal salinity and turbidity maximum variations on the nursery function of the Loire estuary (France)

In the Loire estuary which is a macrotidal estuary, the river flow and tides induce large seasonal variations in salinity gradients and in location and density of the turbidity maximum. These characteristics influence colonization patterns developed by juveniles of euryhaline fish populations (structure, distribution, density) and the dynamics of benthic communities which constitute their food resources. In some hydrological conditions, the upstream limit of the nursery function may be controlled by the turbidity maximum which induces anoxic conditions: reduction in densities or mass mortalities may be observed.     

The trawlfauna of the Mauritanian shelf (Northwest Africa): density,species composition,and biomass

In May 1988, epifaunal trawlsamples were collected at 17 stations on the Mauritanian shelf off the Banc d'Arguin. The species composition and biomass of the invertebrates and demersal fish were analysed. On the basis of species abundances, three station groups could be distinguished each corresponding to a subregion of the shelf: an inner shelf, a midshelf and an outer shelf station group. The average depth increased from 20 m for the inner to more than 100 m for the outer shelf stations. The biomass of mobile epifauna and fish was lowest on the inner shelf stations where the trawlfauna was dominated by large sessile filterfeeders. The trawlfaunas of the mid- and outer shelf were more similar in species composition. Demersal fish and crustaceans appeared to be more abundant on the outer shelf. The increase in density and biomass from inner to outer shelf is discussed in relation to the distribution of the infauna and the hydrographical conditions on the Mauritanian shelf. Being a demersal fishing area, density and biomass of the epifauna on the shelf are compared with that of the demersal fishing grounds in the southern North Sea. The result of this comparison shows that, except for echinoderms, all taxa attain higher densities and biomasses at the Mauritanian shelf.     

Demersal fish assemblages associated with hard bottom habitat in the South Atlantic Bight of the U.S.A.

Synopsis Demersal fish communities associated with hard bottom habitats in the South Atlantic Bight were investigated in three depth zones (inner, middle and outer shelf) between 30° and 33°N latitudes. Fishes were sampled with trawls and baited fishing gear, and were observed by remotely operated underwater television. Most demersal hard bottom fishes demonstrated seasonal differences in abundance in each depth zone, especially at the inner and outer shelf stations. Diversity values from trawl catches were higher in winter than summer at inner and outer shelf stations, but lower in winter at middle shelf stations. Species richness was higher in summer than in winter at most stations, but H' diversity patterns were more influenced by community evenness. Diversity values were higher than those reported for similar depths in the Middle Atlantic Bight. Mean biomass of demersal teleosts for all stations combined was slightly greater in winter than in summer. There was no significant difference in biomass between stations in summer, however, middle shelf stations had significantly greater biomass than inner or outer shelf stations in winter. Biomass estimates from the hard bottom areas studied were considerably higher than those reported in the literature for sand bottom areas in the South Atlantic Bight, but less than those reported for tropical reefs. Cluster analysis revealed differences in community composition between day and night trawl tows at all stations, and greater seasonal differences in species composition at inner and outer shelf stations than at middle shelf depths. Underwater television provided useful complementary data to trawl catches, documented the presence of large fishes which avoided the trawl, and provided information on the community composition at high relief stations which could not be trawled.     

Factors affecting seasonal variations in demersal fish assemblages at an ecocline in a tropical–subtropical estuary

Seasonal changes of fish species composition in terms of biomass, density and number of species in three areas of the main channel of the Paranaguá Estuary (axis east–west) are described in relation to seasonal fluctuations in salinity, water temperature and dissolved oxygen in the main channel. Two hundred and thirty‐four samples were collected monthly, between July 2000 and June 2001, in the main channel. Seventy‐nine species of 29 families were captured with a total estimated mean density and biomass of 1513 individuals ha^?1 and 34 kg ha^?1, respectively. The number of species and total mean density differed significantly among areas and seasons, but the total mean biomass differed only significantly throughout the ecocline (areas) of the Paranaguá Estuary. For the most abundant species, the mean densities of Stellifer rastrifer, Aspistor luniscutis, Menticirrhus americanus, Sphoeroides testudineus, Cynoscion leiarchus and Symphurus tesselatus (with the exception of Cathorops spixii and Genidens genidens) differed significantly among seasons. The mean biomass of these species, with the exception of G. genidens, S. rastrifer, A. luniscutis and S. testudineus, also differed significantly for the factor seasons. Area was a significant factor for the eight most abundant species (density and biomass), except S. testudineus (density), G. genidens, C. leiarchus and S. tesselatus (biomass). The season v. area interaction term was significant for C. leiarchus (density). Most of these differences occurred during the rainy season when fishes concentrated principally in the middle of the estuary, where the salinity remained stable. It is suggested that the salinity stability in the middle of the estuary is the main reason why the most estuarine resident fish species move downstream and remain there, regardless of the increased freshwater runoff. Moreover, canonical correspondent analysis output detected that during the late rainy season, the variable dissolved oxygen (P < 0·01) was the most important environmental variable, responsible for structuring patterns of fishes assemblages in the west–east axis of Paranaguá Estuary. During the end of the dry season, both salinity (P < 0·01) and dissolved oxygen (P < 0·05) were responsible for this ecological feature in the estuary. Finally, it was possible to detect that juveniles and adults of some important species respond differently to seasonal fluctuations of the ecocline‐determining environmental factors. This behaviour is suggested as a strategy to avoid competition and predation during the rainy season in the middle estuary. The Paranaguá Estuary did not fit with the pre‐existing models described in the tropical and subtropical estuarine fish literature since its main channel fish assemblages remained within its bounds even during the rainy season.     

Zooplankton distribution and dynamics in a temperate shallow estuary

The spatial, temporal and tidal dynamics of the zooplanktonic community of the Mondego estuary was studied from January 2003 to 2004. The monthly sampling procedure included the measurement of hydrological parameters (salinity, temperature, Secchi transparency, chlorophyll a and nutrients) and the collection of zooplankton with a Bongo net of 335 μm mesh size. Zooplankton composition, distribution, density, biomass and diversity were determined. The principal component analysis (PCA) revealed the existence of a spatial gradient with the upstream sampling stations, associated to high values of nutrients, in opposition to the downstream stations characterized by higher salinity and transparency values. The Copepoda was the main dominant group and Acartia tonsa revealed to be the more abundant taxon. The spatial and temporal dynamics of zooplanktonic communities analysed by non-metric MDS showed the existence of four assemblages of species-sites, reflecting differences in zooplankton composition between both branches of the estuary. The results suggest that abundance, biomass and diversity of the zooplanktonic community are strongly influenced by the hydrological circulation pattern and by direct or indirect human impacts that occur in each branch. The northern branch is dominated by the river flow suffering from regular dredging activities and the southern branch is dominated by tidal circulation suffering from an ongoing eutrophication process.     

Horizontal biosedimentary gradients across the Sado estuary,W. Portugal

The topography of the Sado estuary, the second largest of Portugal, comprises the outer estuary inside the entrance channel and the inner estuary, on the inward side of which begins the tidal mudflats. The outer estuary subtidal area covers approximately 70 km² and presents a series of longitudinal intertidal sandbanks, separating a northern and a southern channel. A benthic survey was undertaken in the outer estuary during June 1986, in which superficial sediments and macrofauna were sampled at 133 locations. The environmental variables measured in the superficial sediments were the temperature, the granulometric structure, the silt, sand and the gravel content, and the total organic matter content. The primary macrofauna biological variables studied were the species composition, abundance and biomass, calculated on wet, dry and ash-free dry weight. The granulometry and the organic content of superficial sediments agreed with the transient and the residual currents velocity field, simulated in a 2-D hydrodynamic model previously elaborated for the outer estuary. The northern channel superficial sediments showed higher silt and total organic matter content, while the model also suggested lower transient and residual velocities, water flow and shear stress in this channel. The distribution patterns of the subtidal macrofauna were separated into two main groups of species, one comprising taxa essentially settled near the estuarine mouth and the other inwards. Biological primary variables also showed consistent patterns, comparable to other Portuguese estuaries. The major subtidal benthic biotopes were obtained through classification analysis and related to the prevailing hydrophysical and sedimentary conditions in the outer estuary.     

Main characteristics of the boundary layer macrofauna in the English Channel

Four hundred and thirty two suprabenthic hauls with a modified Macer-GIROQ sledge were taken over the period 1988–1996. Fifteen sites within the English Channel were sampled from the Roscoff and Plymouth waters to the Dover Strait, including the Bay of Morlaix, Bay of Saint Brieuc, the Bay of Seine and the Seine Estuary. The main characteristics of the Benthic Boundary Layer (BBL) macrofauna in the English Channel were elucidated from these data. BBL macrofauna was found over the whole water column sampled (10–150 m). Firstly, the number of species collected was very high (up to 116 species for five hauls) except in the Seine estuary. Numerically, mysids were the dominant group of organisms collected with the sledge, followed by amphipods, cumaceans, isopods and decapods. Abundance and biomass of the fauna were very high in the Seine estuary, especially in the mesohaline and oligohaline zones (maximum >216000 ind. 100 m^-3; >200 g AFDW 100 m^-3) where the specialised mysids Neomysis integer and Mesopodopsis slabberi occurred in very high abundance. At other sites, the abundance and biomass were moderate (100–10000 ind. 100 m^-3; 15–2000 mg AFDW 100 m^-3). Abundance reached its maximum when mysids or swarms of amphipods of the genus Apherusa were collected, and during the reproduction of the amphipods of the genus Ampelisca, as in June in the Bay of Morlaix. The number of species, abundance and biomass showed seasonal changes in all sites with, in general, lowest values in winter or spring, and highest values in autumn. For the open sea sites, two main geographical gradients were identified: i) in spring, a higher number of species in the western part of the Channel compared with the eastern part of the Channel and, in autumn, a higher number of species in the eastern part of the Channel compared with the western part, and ii) an increasing density gradient from west to east at spring and a decreasing gradient from west to east during the autumn. The suprabenthic fauna of the Channel can be considered as a unique community including three kinds of species: (i) good swimmer species which were common at all the time and all sites: e.g. Anchialina agilis, Gastrosaccus spp., Haplostylus spp. and Apherusa spp., (ii) species present at all sites only at night: e.g. Atylus vedlomensis, Megaluropus agilis, Melphipidella macra, Orchomenella nana, Pseudocuma longicornis, Schistomysis ornata and Synchelidium maculatum, and iii) species collected at one or a limited number of sites only at night: e.g. Ampelisca spp. at Pierre Noire and Diastylis spp. at site F. The Seine estuary supports a typical suprabenthic estuarine community. Elements of the suprabenthic fauna also showed significant daily rhythms which took several forms depending on the species under consideration.     

The benthic macrofauna along the estuarine gradient of the Schelde estuary

The intertidal benthic macrofauna of the Schelde estuary (The Netherlands and Belgium) was sampled in late autumn of 1990 at 50 stations along the whole salinity gradient (between Vlissingen and Dendermonde), including the freshwater tidal part. All stations were situated in sheltered areas with a relatively muddy sediment. Species richness, diversity and total biomass of the benthic macrofauna decreased along the salinity gradient from Vlissingen to Dendermonde, while total density showed no clear trend. Especially the oligohaline and freshwater tidal part of the Schelde estuary was characterized by a very impoverished benthic community, composed only of Oligochaeta. No other species (freshwater, marine or brackish) was observed in this part of the estuary. The marine part had a more diverse macrozoobenthos structure than that of the brackish part. Species found only in the marine zone areCerastoderma edule, Tharyx marioni, Eteone longa, Nephtys hombergii andCapitella capitata. In the brackish part of the estuary,Corophium volutator was a typical, dominant species. However, a lot of the dominant species were common in both the marine and brackish part of the Schelde estuary (e.g. Heteromastus filiformis, Pygospio elegans, Nereis diversicolor, Macoma balthica). The observed gradient in species composition and dominance is compared with some other European estuaries. The marine and brackish part of the Schelde estuary is quite similar to other european estuaries. The freshwater tidal part, however, was more impoverished.     

Effects of oil/gas field produced water on the macrobenthic community in a small gradient estuary

Little is known about how climatic events (i.e., drought) inhibit or enhance movement of petroleum hydrocarbon laden sediments in estuarine systems and how this in turn effects the macrobenthic populations exposed to these sediments. Seventeen collection stations were established and monitored at New Bayou, Texas, a small gradient estuary which receives petroleum products via oil/gas field produced water discharge. Hydrographic, geologic and biotic samples were taken monthly from each station during a period of reduced rainfall. Both temperature and dissolved oxygen data taken during the study followed patterns typical for the area. Salinity values increased into the polyhaline range at near-bay stations during the reduced rain period, while upper bayou stations remained within the oligohaline range. Sediment grain sizes along the bayou were generally in the silty-clay range. Sediment hydrocarbon concentrations were highest (11.4 mg g⁻¹ dry sediment) around the produced water discharge site and lowest at near-bay stations (0.2 mg g⁻¹ dry sediment). Ninety-six macrobenthic species were collected during the study. General effects from produced water discharge on macrobenthic populations followed the classical pattern outlined by other research in shallow bay systems. A sediment hydrocarbon concentration of 2.5 mg g⁻¹ dry sediment was found to reflect the average value needed to depress population abundances. Both abundance and diversity values were lowest at central stations near the discharge site. This zone of depressed macrobenthic populations extended from the discharge site at least 107 m downstream and 46 m upstream. The zone of stimulated macrobenthic populations occurred 1486 m downstream and 381 m upstream from the discharge site.     

Ecology of the Ogun River estuary,Nigeria

The distribution of benthonic communities (particularly Foraminifera) were studied from fourteen samples obtained from the Ogun River estuary and environs. Ten species of benthonic Foraminifera were identified; two of these constitute over 90% of the total foraminiferal population.Two broad biofacies are recognisable, namely the upper estuarine facies of Ammobaculites and the lower estuarine facies comprising arenaceous and calcereous forms with a preponderance of Ammonia beccarii (Linnaeus).Large populations of few species occur in the lower estuary, an area of weakly saline water with marked salinity fluctuations. The upper estuary on the other hand is sparsely populated and contains tests mainly of arenaeous Foraminifera. A few species are distinctive of particular facies but some are distributed throughout the estuary. Substrate is not a causal ecological factor, because sediments are similar in physical attributes throughout the estuary. Salinity and rate of sedimentation are among the more important factors affecting the distribution of all species. The low-energy nature of the environment is established by the abundance of faecal pellets and the fragility of the tests of the arenaceous Foraminifera.     

Response of alpine meadow communities to burrow density changes of plateau pika (Ochotona curzoniae) in the Qinghai-Tibet Plateau

Plateau pika (Ochotona curzoniae) is a key component of alpine meadow ecosystem in the Qinghai- Tibetan Plateau, and the increase of its number leads plant components of alpine meadow ecosystem to adaptively response. A field survey was carried out to determine the response of alpine meadow community to population densities of plateau pika by using available burrow density to replace the population density of plateau pika. This study showed that the height of alpine meadow communities gradually increased, and the cover of alpine meadow communities firstly decreased, and then increased as the available burrow density increased. With the increase of available burrow density, the richness index of alpine meadow communities firstly decreased and then increased, and the evenness index of alpine meadow communities firstly increased and then decreased, however, the diversity index of alpine meadow communities firstly increased, and then decreased, finally increased. In the increasing process of available burrow density, the total plant biomass and the unpalatable plant biomass firstly decreased and then increased, and the palatable plant biomass firstly increased and then decreased, indicating that the palatable plant biomass was the highest and the unpalatable plant biomass was the lowest at 14 available burrow per 625 m². In the economic groups of plant biomass, the weed biomass was the highest and the legume biomass was the lowest at any available burrow densities, and the grass biomass and the sedge biomass were related to available burrow densities, indicating that the sedge biomass were bigger than the grass biomass at 3 available burrow per 625 m², inverse at 54 available burrow per 625 m², similar between 3 and 34 available burrow per 625 m². Accompanying by the increase of available burrow densities, the legume biomass and the sedge biomass significantly decreased (P < 0.05) and the legume became disappearance at 54 available burrow per 625 m²; the grass biomass firstly increased and then decreased, peaking at 14 available burrow per 625 m². The weed biomass firstly decreased and then increased, and was the lowest at 14 available burrow per 625 m². This study suggested that the responses of alpine meadow communities to population density of plateau pika at 14 available burrows per 625 m² were more sensitive than that at other available burrow per 625 m² from plant species diversity, biomass, height, cover and economic group.     

胶州湾西部海域大型底栖动物多样性的研究

为了揭示胶州湾最近几年底栖动物多样性的变化, 作者于2003年9月到2004年9月在胶洲湾西部海域5个测站每2个月1次共进行了7个航次采样, 以种类组成、生物量和栖息密度为基础, 对大型底栖动物多样性进行了分析。使用PRIMER软件计算得到以下变量: 群落的物种数(S)、丰富度(D)、Shannon-Wiener物种多样性指数(H')和均匀度指数(J')。结果表明: 位于大沽河口的D站和水道中央的S站的多样性最低; 养殖区内外站位的多样性差异显著; 丰度/生物量曲线表明, 养殖区内的底栖动物群落已经受到了一定程度的扰动。群落物种数(S)和丰富度(D)的季节性变化明显, 春季和秋季较低, 夏季和冬季较高。分析菲律宾蛤仔(Ruditapes philippinarum)增养殖区的站位(D)发现, 多样性指数和丰富度与次级生产力有着负相关的关系。物种多样性指数和丰度/生物量曲线的分析显示, 该研究海域处于一个轻度人为扰动的状态。     

环境污染对小清河口大型底栖动物多样性的影响

利用2008年7月小清河口和黄河口各8个站位的底栖动物调查资料,运用多种多样性指数对两河口底栖动物群落多样性特征进行了比较,并运用Spearman相关分析分析了14个环境因素和底栖动物群落多样性特征的相关关系。结果显示,小清河口共有大型底栖动物4门6纲17目35科37属38种,平均分类差异指数为85.7,分类差异变异指数为585.6,黄河口共有大型底栖动物6门9纲24目42科45属48种,平均分类差异指数为89.3,分类差异变异指数为435.8。小清河口的多样性指数(H’)仅约为黄河口的1/3。Spearman相关分析表明,H’与铵盐、硝酸盐、铜和汞含量呈负相关性,说明底栖动物群落多样性随着富营养化程度的提高而相应降低,营养物质氮的大量输入和重金属的污染对小清河口大型底栖动物群落产生了一定负面影响。ABC曲线法分析显示,小清河口底栖动物的丰度优势度曲线与生物量优势度曲线相交,表明小清河口底栖动物群落处于中度干扰状态;BOPA指数显示,小清河口8个站位中有4个站位受到不同程度的环境污染,生活污水和工业废水的排放可能对小清河口底栖动物生态特征带来巨大影响,加强工业和生活污水排放管理,强化清洁生产,加强工业污染源的治理力度,对恢复小清河流域水质、改善生态环境具有重要意义。     

长江口北支浮游植物群落结构周年变化特征

2010年10月至2011年9月对长江口北支水域的浮游植物进行周年调查,共采集到183种（包括变种和变型）,隶属于7门60属,其中硅藻门种类最多,有35属137种,占浮游植物总种类数的75%。周年优势种为具槽直链藻、中肋骨条藻、条纹小环藻、两栖颤藻、小伪菱形藻双楔变种、颗粒直链藻和小环藻未定种。本次调查中,季节间浮游植物的丰度差异不显著（P〉0.05）,但各月间浮游植物丰度差异显著（P〈0.05）,全年丰度在2.83×10^3～6.18×10^4cells/L之间,其中6月的丰度最高,1月的丰度最低,全年的平均丰度为1.73×10^4cells/L。Pearson相关性分析显示,浮游植物丰度与硝酸盐浓度显著正相关（P〈0.05）,与氨氮浓度极显著正相关（P〈0.01）,含氮营养盐对浮游植物的影响明显。