Plankton composition and water quality in a pond of spring origin in Turkey

Phyto/zooplankton composition, chlorophyll a, and some water quality parameters were investigated in a spring-originated pond in Central Anatolia between February 2001 and January 2002. Water temperature, pH, dissolved oxygen, Secchi depth, total and calcium hardness, nitrate-nitrogen, nitrite-nitrogen, ammonia-nitrogen, total phosphorus, and soluble reactive phosphorus levels were analyzed. A total of 49 species belonging to Bacillariophyceae, Chlorophyceae, Cyanophyceae, Cryptophyceae, and Dinophyceae were identified. The highest phytoplankton abundance was found in August, whereas the lowest was determined in January. Phytoplankton abundance increased from February to August and declined in the following months. The Bacillariophyceae were dominant in the phytoplankton community. A total of 21 species of Rotifera, 2 species of Cladocera, and 1 genus of Copepoda were found. The zooplankton community was dominated by Rotifera. The highest abundance of zooplankton was recorded in July and the lowest value in November. The annual mean concentration of chlorophyll a was measured as 1.90 μg l⁻¹. In spite of these eutrophic levels (mean values of total phosphorus and nitrate-nitrogen: 0.069 mg P l⁻¹ and 0.68 mg N l⁻¹), phytoplankton cannot grow satisfactorily because of the short water retention time (0.6 day⁻¹). The shallowness of the pond together with the low phytoplankton biomass and the high concentrations of nutrients are discussed.     

Benthic meiofauna assemblage structure of headwater streams: density and distribution of taxa relative to substrate size

Permanent meiofauna taxa and portions of the population of other invertebrates that are temporarily in the meiofauna size class are often precluded from stream studies and assessments. This study was designed to determine the identity, density, and distribution of major meiofauna taxa relative to substrate size in a set of similar headwater streams. Using a coring technique, meiofauna (80 μm–1 mm) and substrate samples were collected from 11 Ozark headwater streams in the Boston Mountain ecoregion of Arkansas, USA. Mean meiofauna density among streams was 1739 ± 436 organisms per l. Permanent meiofauna taxa (Copepoda, Cladocera, Ostracoda, Rotifera, Nematoda, Hydrachnida, and Tardigrada) comprised 22.5% of the organisms collected with a mean density of 394 ± 233 organisms per l; temporary meiofauna taxa (Oligochaeta, Turbellaria, Hydroidea, Chironomidae, Ephemeroptera, and other insects) comprised the remainder with a density of 1346 ± 308 organisms per l. Chironomidae was the most numerous temporary meiofauna taxon, and Hydrachnida was the most numerous permanent taxon. Streams were found to differ significantly in substrate composition and densities of major taxonomic categories. Substrate size was found to predict densities for most of these taxonomic categories. Meiofauna patchiness was reflected in high variability within streams. Canonical correspondence analysis revealed positive associations between Copepoda and Nematoda and silt, and between Copepoda, Nematoda, and Rotifera and fine sand. Hydrachnida and Rotifera were negatively associated with silt and coarse sand, respectively. The potential value of inclusion of meiofauna in stream environmental assessments is discussed.     

广东长潭水库浮游生物群落结构特征

长潭水库是广东梅州市重要的备用水源地,属于国家一类水源保护区。2010年7月,通过分析长潭水库浮游生物群落组成、生物量及多样性指数等群落结构特征和水体理化指标,揭示长潭水库富营养化水平。结果显示,长潭水库鉴定出55种浮游植物,隶属于6个门,优势种为绿藻门的栅藻（Scenedesmus sp.）、蓝藻门的微囊藻（Microcystis sp.）和伪鱼腥藻（Pseudanabaena sp.）、隐藻门的隐藻（Cryptophyta sp.）以及硅藻门的小环藻（Cyclotella sp.）和针杆藻（Synedra sp.）;藻类密度范围1.71×10⁶~2.44×10⁸ cells/L;浮游动物共检出44种,包括轮虫、枝角类和桡足类,其中轮虫是主要类群。综合营养状态指数评价结果显示,长潭水库部分水体呈轻度富营养化。典范对应分析结果显示,浮游动物、溶解氧、总氮、总磷和化学需氧量是影响长潭水库浮游植物群落结构的关键环境因子。     

Distribution and Interannual Changes of the Zooplankton of the Durgun Water Basin and Adjoining Water Objects (the Western Mongolia)

The article describes quantitative and structural characteristics of zooplankton of polytypic sites of a water system including a lake, canal, and a water reservoir. It is shown that in the littoral zone of lakes and water reservoirs, the number of species and communities is higher, and biomass, lower. However, in the littoral zone of shallow lake zooplankton in number, took priority due to Rotifera, in the deep part of the water body – Rotifera and Cladocera; in the center of the lake zooplankton dominated by biomass due to Cladocera and Copepoda, in the water reservoir—due to the Copepoda. The dam area of the water reservoir had the highest species richness of zooplankton among all studied sites. The greatest number and biomass of zooplankton within a waterbody are noted in upper part, where a sedimentation zone had formed, and as a whole for the system of the investigated waterbodies, the maximum quantity indices are typical of lake communities. It is revealed that the starkest interannual changes in zooplankton were observed in the shallow lake: the number of species decreased—in the littoral zone at the expense of Rotifera, and in the center, the biomass increased at the expense of Cladocera; in deep-water area of the dam area of the reservoir, conversely, the number of species, as well as the number and biomass of the community, increased due to Copepoda.     

Physico-chemical limnology and plankton dynamics of Mazvikadei,a tropical reservoir in Zimbabwe

The limnology of Mazvikadei Reservoir, northern Zimbabwe, was investigated in 2015 to determine whether it had changed since filling in 1990. The reservoir is characterised by low algal biomass, low nutrients (i.e. N and P) and high water clarity/transparency. Fifty-four species of phytoplankton were recorded, comprising Bacillariophyta, Chlorophyta, Cyanophyta, Desmids, Dinophyta and Euglenophyta. Chlorophyta numerically dominated in the hot dry season, whereas Bacillariophyta, Desmids, Dinophyta and Euglenophyta dominated in the cool dry season. Species richness was highest at the onset of the cool dry season, in response to high nutrient concentrations. Phytoplankton abundance and composition were significantly correlated with temperature, nitrates and total nitrogen. Nineteen zooplankton species were recorded, including Copepoda, Cladocera and Rotifera. Overall, Cladocera were numerically dominant and became most abundant during the cool dry season. Rotifers and copepods dominated during the hot dry season. The zooplankton abundance was correlated with reactive phosphorus and phytoplankton abundance. The trophic state of Mazvikadei Reservoir seems to have stabilised and to have assumed the physico-chemical characteristics and plankton community typical of an oligotrophic lake.     

Features of the structure and spatial distribution of plankton in the Sheksna Reservoir

Based on the field studies conducted in August 2005 and 2007, the distributions of zooplankton structure and abundance, as well as chlorophyll content, in the Sheksna Reservoir are analyzed. A total of 107 zooplankton species have been found (46 Cladocera, 18 Copepoda, and 43 Rotifera), including 24 species (10 Cladocera, 2 Copepoda, and 12 Rotifera) new for the reservoir. In the surface layer of water, where blue-green algae concentrate, zooplankton abundance and biomass are 1.5–5 times lower and the zooplankton structure is simpler than in deeper layers. The highest zooplankton biomass (>3 g/m³) are observed in Lake Beloe and the upper area of the Sheksna section, while in the near-shore sites it did not exceed 1 g/m³. There are no significant changes in zooplankton abundance when compared to the abundance recorded at the end of the past century.     

Zooplankton dynamic of Lake Prespa (Macedonia)

The composition and temporal abundance patterns of zooplankton community in Lake Prespa pelagic zone were studied throughout an annual cycle (October 2008–September 2009). Eighteen species (10 Rotifera, 5 Cladocera, 2 Copepoda, 1 Mollusca) were evidenced. It includes Arctodiaptomus steindachneri, an endemic calanoid of the Western Balkans. The zooplankton density varied during the investigated period and certain seasonal successions in temporal transpositions of their maximal development were noticed. The total zooplankton density was much higher in spring and summer period. The representatives of subclass Copepoda were dominant during the whole year. The dominant species was A. steindachneri. At the second place (with exception of the winter period) were the Cladocera representatives. The dominant species was Daphnia cucullata. At the third and fourth place were rotifers and larval form of Dreissena polymorpha, respectively. The quantitative presence of the Copepoda representatives was significantly lower in terms of the previous investigations. The Cladocera quantity reached high values during this period, particularly in summer. Such altering in the quantitative ratio between Copepoda and Cladocera in favor of the Cladocera, especially high quantitative presence of D. cucullata, typical for eutrophic lakes, imply of significant changes in zooplankton community and changes of the water quality in Lake Prespa pelagial.     

Effets de la mise en eau du réservoir Desaulniers (Territoire de la Baie de James) sur le zooplancton d'une rivière et d'une tourbière reticulée

This paper presents the results of an investigation which lasted three years, on the effects of impounding a river on its zooplankton community. Forty zooplankton samples were collected from the Desaulniers River and from a string bog (53°35N, 77°35W) in 1976 before impoundment. Sampling was also conducted in 1977 (331 samples) and 1978 (153 samples) during and after impoundment. The population dynamics of zooplankton show different patterns in 1977 and 1978. The main impacts of impoundment on the river and the bog communities are the increase of the population density, particulary of Rotifera and Copepoda, the increase of the number of species of Rotifera and the increase of the diversity indices based on numbers and biomass. These changes are observed at each sampling station. The total biomass increases in lotic stations but decreases in the string bog because the density and the biomass of Cladocera increases in the river but drops in the bog. Results are compared to those obtained in natural lakes and bog of the same area and to those published in other studies.

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Effets de la mise en eau du réservoir Desaulniers (Territoire de la Baie de James) sur le zooplancton d'une rivière et d'une tourbière reticulée

     

Zooplankton assemblage concordance patterns in Brazilian reservoirs

The main goal of this study was to evaluate the assemblage concordance among three zooplankton groups (Rotifera, Cladocera and Copepoda) in 30 Brazilian reservoirs. According to Mantel tests and Procrustean analyses, there was a high level of assemblage concordance. Highest assemblage concordance was observed between cladocerans and copepods, while the lowest level of concordance was detected between copepods and rotifers. Based on environmental or biotic data, patterns of among-reservoir dissimilarities were fairly stable across the two seasonal periods analyzed in this study. Multiple Mantel tests were used to model the between-reservoir dissimilarities (Bray–Curtis distance) in zooplankton assemblage structure as a function of the limnological, geographical and morphological distances between pairs of reservoirs. The best predictor of faunistic dissimilarities was the matrix containing the limnological distances among the reservoirs. In general, these results are important for monitoring purposes because they supported the use of surrogate taxa and indicate that community concordance analysis may be a powerful tool for enhancing the efficiency of monitoring programs, ensuring their long-term sustainability. Handling editor: S. I. Dodson     

Anaesthesia of free-ranging Northern chamois (<Emphasis Type="Italic">Rupicapra rupicapra</Emphasis>) with xylazine/ketamine and reversal with atipamezole

One-hundred and fifty-five free-ranging Northern chamois (Rupicapra rupicapra) were anaesthetised in the course of a restocking programme using xylazine plus ketamine. Mean ± SD dosages for xylazine and ketamine were 1.9 ± 0.5 and 2.2 ± 0.7 mg/kg, respectively. In 57 chamois, sedation was reversed using 0.3 ± 0.1 mg/kg atipamezole. Although all the anaesthetic dosages tested immobilised free-ranging Northern chamois, shorter induction times (4.8 ± 2.6 min), deeper sedation with no reaction to handling in >90% of the animals and quick reversal (4.0 ± 2.7 min) were obtained using 2.5 mg/kg xylazine plus 3.0 mg/kg ketamine reversed with 0.25 mg/kg atipamezole. Under the conditions of this study, suggested standard doses are 63 mg/animal xylazine plus 76 mg/animal ketamine reversed by 6.3 mg/animal atipamezole. This anaesthetic protocol improves the results from the previous study of Dematteis et al. (Vet Rec 163:184–189, 2008) using xylazine alone.     

浙江两类饮用水源地浮游动物种类组成及其类群相关性分析

于2009年7月至2010年4月,在浙江省选取了10个水库和10个河网饮用水源地,进行4个季节的浮游动物采样调查。记录浮游动物101种(轮虫60,枝角类24和桡足类17种)。水库和河网轮虫的优势种分别为角突臂尾轮虫(Brachionus angularis)和针簇多肢轮虫(Polyarthratrigla),枝角类分别为颈沟基合溞(Bosminopsis deitersi)和长额象鼻溞(Bosmina longirostris),桡足类均为温剑水蚤(Thermocyclops)。水库中有一些能指示良好生态或水质的指示性种类。水库枝角类与桡足类群落之间周年在丰度和生物量上均有极显著的正相关关系(P<0.01),轮虫与桡足类类群之间的相关性最弱;河网枝角类与桡足类在夏、秋、冬季有显著的正相关性(P<0.05)。浮游动物类群之间的相关性程度,以水库的秋季与河网的夏季为最高。轮虫与浮游甲壳动物的种类丰富度随着饮用水源水体透明度的变化呈现相反的变化趋势。     

Micropropagation of <Emphasis Type="Italic">Vitex agnus-castus</Emphasis>, (Verbenaceae)—a valuable medicinal plant

This study describes in vitro shoot induction and plant regeneration from a mature apical meristem and nodal explants of the endangered medicinal shrub Vitex agnus-castus. Multiple shoots were induced directly from the axis of nodal and apical meristem explants on Murashige and Skoog (MS) medium containing 3% sucrose and different concentrations (1.0, 1.5, 2.0, and 2.5 mg/l) of 6-benzyl aminopurine (BAP) in combination with Kinetin (Kin) and α-naphthalene acetic acid (NAA), both at 0.1 mg/l. BAP and Kinetin were used as supplements to MS basal medium, either individually or in combination with auxins. The optimal concentration of BAP for inducing bud break was found to be 2.0 mg/l when Kinetin was at 0.1 mg/l. Regeneration frequency was highest for both apical meristem and nodal explants (94.5% and 90.3%, respectively) when explants were cultured on MS medium supplemented with BAP (2.0 mg/l) and Kin (0.1 mg/l). A maximum of 7.7 ± 0.4 and 6.7 ± 0.2 shoots were obtained per explant for apical meristem and nodal explants, respectively. Regenerated shoots, transferred to MS medium supplemented with either 1.0 or 1.5 mg/l BAP combined with 0.1 mg/l GA₃, showed maximum elongation of 6.7 ± 0.4 and 6.0 ± 1.3 cm in apical meristem and nodal explants, respectively. In vitro regenerated shoots transferred to half-strength MS medium supplemented with 0.1 mg/l IBA induced 90.4% of the shoots to form roots after 30–35 d of culture. Up to 80% of the regenerated shoots were successfully established in soil in the greenhouse.     

清河水库的浮游生物

根据1970,1973,1974,1977,1978和1979年17次采样测定的结果,清河水库浮游植物量平均约6毫克/升,其中硅藻占58.6%,甲藻占25.9%。浮游动物量平均1.95毫克/升,其中桡足类约占44%,枝角类约40%,轮虫和原生动物约16%。浮游植物量上游和中游接近而远高于下游,一般秋季高于其他季节,但1978年夏季特别高。浮游动物量也是中游和上游通常高于下游,夏季最高,秋季次之。在生物量中占优势的主要种类有:颗粒直链藻、扭曲小环藻、隐藻、角甲藻、剑水蚤及其无节幼体、象鼻溞、长刺溞、多肢轮虫等。文中讨论了浮游生物分布和变化的某些规律和水库的营养类型及鲢鳙鱼的生产潜力。       

Shifts in zooplankton communities in high-mountain lakes induced by singular events (fish stocking,earthquakes): evidence from a 20-year survey in Slovenia (Central Europe)

Thirteen mountain lakes, originally fishless, at 1325 and 2150 m a.s.l., with the maximum depths ranging from two to 15 m, and areas of 0.3 to 4.5 ha, were monitored between 1991 and 2012 in the Triglav National Park (Slovenia, Central Europe). The lakes are located on limestone bedrock, with no surface inflow or outflow. They range from ultra-oligotrophic to hypertrophic. They were stocked with fish between late 1920s and 1996. The zooplankton samples were collected as composites from the bottom to the surface at the deepest point of the lake, for both qualitative and quantitative analyses. In situ physical parameters in the water column were measured, and the samples for chemical analyses were collected in parallel with the zooplankton sampling. Thirty-two species, including Copepoda, Cladocera, Rotifera and Ciliata, were recorded. They belonged to three ecological groups: (1) constitutive, (2) scout and (3) benthic species. In some of the lakes, the species composition remained stable over the study period, but in lakes stocked with fish, significant changes occurred, in both species composition and biomass. Large-bodied species of Copepoda and Cladocera were eliminated by fish allowing small-bodied planktonic species of Copepoda, Cladocera and Rotifera to dominate the community, along with benthic species, associated with algal mats. The lake, stocked with fish in the 1920s, was hit by two strong consecutive earthquakes, in 1998 and 2004, after which a significant change in species composition and biomass was recorded.

     

Ontogenetic shift in dietary preference and low dietary overlap in rohu (<Emphasis Type="Italic">Labeo rohita</Emphasis>) and common carp (<Emphasis Type="Italic">Cyprinus carpio</Emphasis>) in semi-intensive polyculture ponds

In order to investigate ontogenetic changes in diet and diet overlap between rohu (Labeo rohita) and common carp (Cyprinus carpio) in polyculture ponds, food preferences of different size classes of these fishes were quantified. Rohu diet consisted of both phytoplankton and zooplankton, and there was a distinct ontogenetic shift in the relative importance of these food items. Zooplankton was the dominant food for rohu up to 20.6 cm total length (TL) and then gradually decreased in importance as fish grew. Phytoplankton was initially a minor component of rohu diet but gradually increased in importance and became the dominant food for rohu at 24.2 cm TL. Phytoplankton biovolume in rohu guts was positively correlated with fish size (TL). Chesson’s α indicated that rohu of all sizes preferentially selected Cladocera and avoided Cyanophyceae and Euglenophyceae. Young rohu initially preferred Rotifera and Copepoda but gradually switched to Bacillariophyceae and Chlorophyceae. Common carp diet consisted of phytoplankton, zooplankton, and benthic macroinvertebrates, but was dominated by benthic macroinvertebrates (63–92% of total diet). As common carp grew, the proportion of zooplankton ingested decreased and the proportion of benthic macroinvertebrates increased. Benthic macroinvertebrate biovolume in common carp guts was positively correlated with fish size. Common carp of up to 15.4 cm TL preferentially selected zooplankton, but common carp larger than 18.9 cm TL avoided this food item. Common carp of all sizes avoided phytoplankton. A low dietary overlap was found between rohu and common carp (Schoener overlap index: 0.08–0.35), probably due to ingestion of smaller quantities of zooplankton by the latter. Dietary overlap also decreased with increasing rohu and common carp size because of divergent ontogenetic shifts in dietary preferences of the two species.     

Effects of Rewetting Measures in Dutch Raised Bog Remnants on Assemblages of Aquatic Rotifera and Microcrustaceans

Species differ in their life cycle, habitat demands and dispersal capacity. Consequently different species or species groups may respond differently to restoration measures. To evaluate effects of restoration measures in raised bog remnants on aquatic microinvertebrates, species assemblages of Rotifera and microcrustaceans were sampled in 10 rewetted and 10 non-rewetted sites, situated in 7 Dutch raised bog remnants. A total of 129 species (Rotifera 108, Cladocera 15, Copepoda 6 species) were found. The species assemblages, total numbers of species and numbers of characteristic raised bog species did not differ between the 10 rewetted and 10 non-rewetted sites. The dominant pattern in the variation in microinvertebrate assemblages could be explained by the presence or absence of open water and variation in physico-chemical variables of surface water and organic matter. Furthermore, the species assemblages of water bodies situated in the same area were on average more similar to each other than to assemblages from other areas. These differences between areas may be due to differences in environmental conditions of water bodies, and possibly also to differences in the local species pool and the subsequent immigration sequence of species. We conclude that, in contrast to earlier findings on aquatic macroinvertebrates, populations of microinvertebrate species, including characteristic species, can either persist in the raised bog remnants during the process of rewetting or (re-)establish within a relatively short period of time (less than about 5 years).     

Water quality and plankton periodicity in two contrasting mine lakes in Jos,Nigeria

Water quality and plankton periodicity was studied in two mine lakes near Jos in the younger granite area of Plateau State, Nigeria. The investigation was carried out for 8 months. Transparency, pH and NO₃-N were significantly higher in Lake II while DOM, alkalinity, PO ₄ ^3– -P, BOD and chloride were significantly higher in Lake I. The order of dominance in Lake I was Bacillariophyceae, Cyanophyceae, Chlorophyceae and Dinophyceae while for Lake II; Chlorophyceae, Cyanophyceae, Bacillariophyceae and Dinophyceae. In Lake I the zooplankton in order of dominance were Cladocera, Rotifera, Copepoda, and nauplii and in Lake II Cladocera, Copepoda, Rotifera and nauplii. Although both lakes would seem unproductive based on the PO ₄ ^3– -P and NO ₃ ^– -N levels, Lake I appears more productive than Lake II.     

Zooplankton associations in East African lakes spanning a wide salinity range

Abstract The zooplankton of 38 East African lakes has been analysed in terms of species richness and dominance. The conductivities of the lakes range from 48 to 72 500 µS cm^–1 20 °C. The lakes generally contain more species of rotifers than either Copepoda or Cladocera. The number of species of rotifers begins to decline at a conductivity below 1000 µS cm^–1, and falls to 2 or 3 species above 3000 µS cm^–1. Similar reductions occur in the Copepoda and Cladocera.Many species can be dominant at conductivities below 1000 µS cm^–1, but the range is restricted progressively with increasing salinity. The dominant species of Rotifera, Copepoda and Cladocera change independently along the salinity gradient, but there are indications of interactions and modifications of community structure by predation and competition.     

Phytoplankton biomass and production during late austral spring (1991) and summer (1993) in the Bransfield Strait

Phytoplankton biomass and productivity were measured during two cruises in the Bransfield Strait in December 1991 (D91) and January/February 1993 (J93). Strong seasonal variability in productivity values was observed due to differences in the physiological response of phytoplankton. However, although the photosynthetic capacity of phytoplankton was markedly lower in D91 [P _m ^B =0.61 ± 0.25 mg C (mg Chla)⁻¹ h⁻¹] than in J93 [P _m ^B =2.18 ± 0.91 mg C (mg Chla)⁻¹ h⁻¹], average water column chlorophyll values in different areas of the strait were approximately similar in D91 (49–78 mg Chla m⁻²) and J93 (22–76 mg Chla m⁻²). The spatial distribution of chlorophyll was patchy and generally associated with the influence of the different water masses that meet together in the Bransfield Strait. No correlation was found between the mixed layer depth and either the integrated chlorophyll or the productivity. Our results suggest that major phytoplankton blooms in the Bransfield Strait are advected from the nearby Gerlache Strait or Bellingshausen Sea following the main eastward surface currents. Accepted: 5 July 1998     

水质酸化和模拟酸雨对浮游动物影响的研究

在水质酸化和模拟酸雨试验中,共出现浮游动物17种,其中包括轮虫9种、枝角类6种和桡足类2种.在pH5.0-8.3各试验组出现种类数(10-13种)和个体数(223.0-334.5个·L^-1)较多,而在pH3.0和4.5试验组出现种类数(5-9种)和个体数(16.8-182.0个·L^-1)较少,表明pH5.0以下对浮游动物群落有明显的影响.从不同类群出现所占比例看,在pH5.5以下,随着pH的下降,存在着轮虫逐渐取代桡足类的趋势.