ZOOPLANKTON OF SMALL LAKES IN THE EASTERN PART OF THE CATCHMENT AREA OF LAKE VOZHE (VOLOGDA OBLAST)

In the summer period of 2017–2020, the authors studied the composition, dominant complex and the abun-dance of zooplankton in 23 small lakes in the eastern part of the Lake Vozhe catchment area (Vologda oblast). The lakes are located in lacustrine-glacial, moraine-hilly and moraine-plain landscapes. A total of 121 species are recorded in zooplankton of the lakes (Rotifera – 38, Cladocera – 56, Copepoda – 27) including Holopedium gibberum, Daphnia pulex, Bunops serricaudata, Paralona pigra, Chydorus ovalis, Acanthodiaptomus denticornus denticorn that are relatively rare species for the region. The highest occurrence is typical for eurybiontic species. The planktonic fauna of the waterbodies of lacustrine-glacial terrains is sui generis (the index of similarity with other lakes is 0.4). The level of similarity in the composition of zooplankton in moraine lakes is 0.7 on average. Zooplankton in the lakes of different landscape types differs in the structure of dominant complex. The set of dominants in the reservoirs of the lacustrine-glacial terrains is sui generis (Keratella cochlearis, Daphnia galeata, Eudiaptomus graciloides, Heterocope appendiculata). The composition of zooplankton dominants in moraine lakes is more diverse. Most of these waterbodies are dominated by Kellicottia longispina, Keratella cochlearis, Bosmina longirostris, Thermocyclops oithonoides. In the lakes of the moraine-hilly landscape, the set of dominants also includes Eudiaptomus gracilis and E. graciloides, and in the moraine-plain water bodies Asplanchna priodonta, Diaphanosoma brachyurum, Ceriodaphnia pulchella, Polyphemus pediculus are dominant. The highest average abundance (137.7 thousand ind./m3) and biomass (1.8 g/m3) are typical for the lakes in moraine-plain landscapes. The morphology of the depressions of these lakes contributes to the development of macrophyte thickets. The abundance and biomass of zooplankters in waterbodies of the lacustrine-glacial landscapes are 58.9 thousand ind./m3 and 0.8 g/m3, respectively. The development of macrophytes in these reservoirs is limited by a rapid increase in depth and the predominance of peat and peat-silt soils.

The rotifera fauna of the Bayezid Bostami pond of Chittagong city

Rotifera fauna of Bayezid Bostami pond was studied for a period of one year from February 2013 to January 2014. Brachionus diversicornis, B. angularis, B. quadridentatus, B. falcatus, B. calyciflorus, B. forficula, B. caudatus, Platyias patulus, Keratella cochlearis, Lecane luna, Trichocerca cylindrica, Polyarthra vulgaris, Asplanchna priodonta, A. brightwelli, Filinia longiseta and F. terminalis were common species present throughout the year. Highest abundance of rotifer was observed in the month of September, and lowest was observed in the month of March. The responsible species for the peak were Brachionus angularis and B. diversicornis. Description of each species, monthly fluctuation and photographs are the content of this paper.Bangladesh J. Zool. 43(1): 95-108, 2015

Variación estacional del zooplancton del embalse Ignacio Allende, Guanajuato, México y su relación con el fitoplancton y factores ambientales

Se estudiaron las comunidades planctónicas y los factores ambientales del embalse Ignacio Allende de julio de 1990 a junio de 1991. Se presentó una proliferación de ciaIlofíceas ell el verano coincidente con el mayor nivel de agua, seguido por la dominacia de bacilariofíceas ell los meses mos, en primavera con el incremento en la temperatura las cJoroficeas alcanzaron sus mayores densidades. Las dinofíceas y euglenofíceas presentaron la menor riqueza específica. La proliferación de Anabaena variabilis en el verano y la alta frecuencia de Ceratium hirundinella, Aufacosseira granulara y FragUaria crolonensis se asocian con cuerpos de agua tropicales eutróficos. Se encontraron 39 taxones zooplanctónicos, de los cuales Diaphanosoma birgei. 80smina fongirostris, Daphnia parvula, Diaptomus (Mastigodiaptomus) montezumae, Acanthocyclops vemalis, Kerate[ la cochlearis, Polyarthra vulgaris y Asplanchna priodonta, fueron persistentes en todo el ciclo. Un análisis de correspondencias canónicas mostró las relaciones que guardan los cambios en composición del zooplancton con las características físicas y químicas del embals

Food spectrum of the omnivorous rotifer Asplanchna priodonta in two large northeastern European lakes of different trophy

In this paper we examine the stomach contents of the omnivorous rotifer, Asplanchna priodonta, to evaluate possible trophic interactions between this rotifer and its potential prey in two large northeastern European lakes: moderately eutrophic Lake Peipsi and strongly eutrophic Lake Võrtsjärv. Our results show that the A. priodonta diet consisted of Bacillariophyta, Chlorophyta, Cyanobacteria, and Dinoflagellata. Ciliata were detected on rare occasion. Bacillariophyta were the most frequent food items in stomachs. There were no between-lake differences in the consumption of Chlorophyta and Cyanobacteria, whereas Bacillariophyta were consumed more in Lake Peipsi. However, neither Dinoflagellata nor Ciliata were found in stomach samples in Lake Võrtsjärv. We conclude that A. priodonta is an opportunistic feeder that is capable of influencing the phytoplankton community structure in large lakes.

Rotifera of the Três Lagoas Lake Complex, João Pessoa, state of Paraíba, Brazil

The aim of the present study was to survey the rotifer composition of the Três Lagoas Lake Complex in the city of João Pessoa, state of Paraíba, Brazil. These urban lakes receive waste from the surrounding neighborhoods. Samples were carried out every two months between August 2008 and August 2009. The rotifers were identified using an optical microscope and specialized literature. Seventeen species were found, distributed among eight families and ten genera. Brachionidae was the most representative family. There were four new records for the state of Paraíba – Asplanchna priodonta (Gosse, 1850), Asplanchna sp., Rotaria rotatoria (Pallas, 1766) and Squatinella sp.

Seasonal variations in the length of zooplankton related to certain physicochemical variables in two freshwater reservoirs

Seasonal variations in the body length of zooplankton were studied in relation to water temperature, nitrate (NO3), soluble reactive phosphorus (SRP), total chlorophyll, Secchi disk depth, pH, conductivity, and oxidation-reduction potential (ORP) in a mesotrophic (Ikizcetepeler) and a eutrophic (Çaygören) reservoir from February 2007 to March 2008. During the study, the body lengths of a total of 7590 zooplankton specimens (1110 rotifers, 3270 cladocerans, and 3210 copepods) were measured. The length of the majority of the species was significantly smaller in summer than in winter, fall, and spring, including that of the most dominant species, Asplanchna priodonta, Daphnia galeata, Daphnia longispina, Diaphanosoma brachyurum, Bosmina longirostris, Leptodora kindtii, Ceriodaphnia pulchella, Cyclops vicinus, Metacyclops gracilis, and Acanthocyclops robustus (F > 5, ). Correspondence analysis (CA) showed that the body length of the zooplankton studied was inversely related to water temperature, whereas it was positively related to ORP and pH. The results of our study suggest that, although nutrients (NO3 and SRP) apparently have an effect on zooplankton body length only in the mesotrophic reservoir, temperature influences the body length in both the mesotrophic and the eutrophic reservoir.

Comments on the diet of Asplanchna priodonta (Gosse, 1850) in the Dobczycki dam reservoir on the basis of field sample observations

Comments on the diet ofDuring a monitoring programme the diet composition of

Omnivory of the larval phantom midge (Chaoborus spp.) and its potential significance for freshwater planktonic food webs

Developmental and seasonal changes in the preferred prey and the diet composition of the invertebrate predator Chaoborus punctipennis were determined in Plastic Lake, an acidified (pH 5.6) lake in south-central Ontario, Canada. All instars consumed rotifers (mainly Keratella cochlearis, Ploesoma sp., and Asplanchna priodonta), and instars III and IV fed preferentially on crustaceans (mainly bosminids and copepods). Phytoflagellates (Peridinium sp. and Dinobryon sp.), however, numerically dominated the diet of all instars examined (II–IV), and were consumed by instar II larvae in excess of their relative availability. On 40 and 20% of the sampling dates, instars III and IV, respectively, consumed phytoflagellates in accordance with their relative abundance in the lake. Although the contribution of phytoflagellates to the biomass-based diet of C. punctipennis was low, on one occasion phytoflagellates formed almost half of the diet biomass of instar II larvae. A review of the literature shows that in lakes where phytoflagellate densities are high (≥ 100–200/mL), phytoflagellates contribute ≥ 50% of the diet biomass of all instars of Chaoborus spp. These findings indicate that Chaoborus spp. are omnivores that frequently feed on phytoflagellates even when alternative animal prey are abundant. Consumption of phagotrophic phytoflagellates by Chaoborus spp. and other large invertebrate omnivores, such as Mysis spp., Epischura spp., and cyclopoid copepods, may increase the transfer efficiency of organic carbon from the microbial food web to the upper trophic levels in fresh waters. In acidified lakes, consumption of large dinoflagellates by Chaoborus spp. and other invertebrate omnivores may ameliorate the hypothesized bottleneck impeding the flow of carbon between phytoplankton and zooplankton.

A General Approach to the Culture of Planktonic Rotifers

A general method for establishing cultures of planktonic rotifers from natural waters is described. Algal isolates are tested for their suitability as food for rotifers collected from the same source and season. Rotifer clones displaying the highest reproductive rates under the given culture conditions are selected for the final culture system. This procedure yielded indefinite cultures for the eulimnetic species, Asplanchna priodonta, A. herricki, Polyarthra major, and Synchaeta pectinata, and appears to have a good probability of success when the diet of a species is unknown. Algal isolates from the same source as the rotifers produced better results than algae obtained from commercial sources. Cryptomonad species produced the most consistent positive responses in growth and reproduction of rotifers tested.Key words: rotifers, zooplankton culture, Asplanchna, Polyarthra, Synchaeta, Cryptomonas