Centric diatom algae (Centrophyceae) in waterbodies and water courses of the middle Irtysh basin

Light and scanning electron microscopy studies of centric diatoms of the plankton in the middle Irtysh River and waterbodies and water courses of its basin have revealed 21 taxa of Centrophyceae from 9 genera, including 14 new for the region. A revision of the species composition allowed us to specify and broaden the list of centric diatoms in the Omsk Priirtyshye up to 30 species.     

Centric diatom algae of volcanic Verkhneavachinsk lakes (Kamchatka)

Eleven representatives of diatom algae of the class Centrophyceae from the genera Aulacoseira (1), Conticribra (1), Cyclotella (5), Discostella (1), Stephanodiscus (2), and Thallasiosira (1) have been found in the phytoplankton of 5 volcanic lakes (Bakening volcano, Kamchatka). Stephanodiscus popovskayae, a species new for science, has been discovered in all the lakes, and a species new for the flora of Russia, Cyclotella gordonensis, has been found only in three lakes. The closest similarity in the composition of centric diatoms has been revealed between the lakes of a single water system: Lake Medvezh’e and Lake Verkhneavachinskoe.     

Centric diatoms (Centrophyceae,Bacillariophyta) in watercourses and bodies of water in southeast of West Siberian Plain and Polar Ural

The study of phytoplankton from rivers and lakes in the southeastern part of the West Siberian Plain and the eastern macrosclope of the Polar Ural by scanning electron microscopy has revealed 25 taxa of Bacillariophyta from the class Centrophyceae (seven Aulacoseira, one Cyclostephanos, four Cyclotella, two Discostella, one Melosira, one Puncticulata, seven Stephanodiscus, and two Thalassiosira), including new species for the flora of the investigated bodies of water. The revision of the species composition of Centrophyceae in bodies of water and watercourses in the southeast part of the West Siberian Plain has allowed more exact identifying the taxonomic spectrum of this class. At present, the list includes 55 species, varieties and forms. During first studies conducted in rivers and lakes of the Lyapin River basin (Polar Ural) 16 species of centric diatoms that belong to the genera Aulacoseira, Cyclostephanos, Cyclotella, Discostella, Puncticulata, and Stephanodiscus have been recorded.     

Centric diatoms (Bacillariophyta,Centrophyceae) in Karelian waterbodies

Materials on phytoplankton from 11 Karelian lakes located in the basins of the White and Baltic seas were studied by scanning electron microscopy; 22 representatives of diatom algae of the class Centrophyceae, including those that are new for the flora of the lakes (Aulacoseira lacustris, A. perglabra, A. tenella, A. valida, Discostella cf. pseudostelligera, S. invisitatus) and new for Karelia (Brevisira arentii, Stephanodiscus delicatus), have been recorded. A revision of the species composition of Centrophyceae in the waterbodies of Karelia has been made. Diagnoses and the systematic status of some species, varieties, and forms have been specified. A new list includes 51 taxa from 12 genera: Acanthoceras (1), Aulacoseira (23), Brevisira (1), Cyclostephanos (1), Cyclotella (7), Discostella (2), Ellerbeckia (2), Melosira (2), Puncticulata (1), Rhizosolenia (3), Stephanodiscus (7), and Thalassiosira (1).     

Centric diatom algae of the Selenga River and its delta branches

Different stages of the study of taxonomical composition of centric diatoms in the Selenga River are considered. A revision of the species composition and a general systematic list are made. New for the Selenga River diatom species are discovered. The role of small-sized centric diatoms in different years and vegetation periods is assessed. A comparison of the composition and the level of development of centric diatoms in 1958–1959 and 2002–2005 is made.     

New data on the flora of diatom algae (Centrophyceae) in waterbodies of Sakhalin Island

The first studies of phytoplankton in inland waterbodies of Sakhalin Island by electron microscopy have revealed 19 representatives of the class Centrophyceae, including some that are new for the flora of the region (Aulacoseira subarctica, Coscinodiscopsis commutata, Stephanodiscus delicatus, S. makarovae, Thalassiosira baltica, and T. cf. hyalina). Species of centric diatoms that are new for these waterbodies have been documented in lakes Vavaiskiye and Tunaicha, and the species composition of Centrophyceae have been revised. The first complete data on the taxonomical spectrum of Centrophyceae in Lake Sladkoye, lakes of Mount Spamberg, and the Tym River have been obtained. A revision of the species composition of Centrophyceae in the waterbodies of Sakhalin Island has been made, and the list of the class has been broadened to 44 taxa from 17 genera.     

Karyotype of Chukotka char from Estikhed Lake (Eastern Chukotka)

The karyotype of chars from the Estikhed Lake (Eastern Chukotka) was examined. This karyotype comprises 78 chromosomes, NF = 98. Marker chromosomes include one pair of submetacentrics, one pair of large acrocentrics, and one pair of large subtelocentrics with very short second arms. Nucleolus organizer regions are located in telomeric regions of short arms of marker submetacentric chromosomes. Small heterochromatin blocks are observed in centromeric regions of most chromosomes. The Chukotka char karyotype is very similar to that of Taranetz char Salvelinus taranetzi from the Achchen Lake: these karyotypes differ only in stability of the chromosome number.     

The Karyotype of Chukotka Chars from the Estikhed Lake (Eastern Chukotka)

The karyotype of chars from the Estikhed Lake (Eastern Chukotka) was examined. This karyotype comprises 78 chromosomes, NF = 98. Marker chromosomes include one pair of submetacentrics, one pair of large acrocentrics, and one pair of large subtelocentrics with very short second arms. Nucleolus organizer regions are located in telomeric regions of short arms of marker submetacentric chromosomes. Small heterochromatin blocks are observed in centromeric regions of most chromosomes. The Chukotka char karyotype is very similar to that of Taranetz charSalvelinus taranetzi from the Achchen Lake: these karyotypes differ only in stability of the chromosome number.     

Stomatocysts of chrysophyte algae from bodies of water in territory near Irtysh river in Omsk Region and Lake Teletskoe in Gorny Altai,Russia

The distribution of stomatocysts of chrysophyte algae in the plankton of bodies of water of different types in the basin of the middle reach of the Irtysh (at the Omsk Region), as well as in the plankton and in fouling of the deep-water oligotrophic lake Teletskoe (Gorny Altai) has been considered. The classification of morphotypes of stomatocysts has been carried out. The number of morphotypes found in plankton samples from bodies of water of the middle Irtysh basin is 30 and, in Lake Teletskoe, 60. Four similar morphotypes of cysts were revealed for the bodies of water under investigation.     

Molecular genetic identification and phylogeny of Daphnia species (Crustacea, Cladocera) from water bodies of the Lake Chany basin

The data on the molecular genetic identification of Daphnia species from the water bodies of the Lake Chany basin are presented. Phylogenetic relationships between these species have been established. The fragments of the mitochondrial DNA genes were used as genetic markers. According to the data obtained, the water bodies examined were inhabited by five Daphnia species, including Daphnia (Daphnia) galeata Sars, D. (D.) longispina O. F. Müller, D. (D.) curvirostris Eylmann, D. (D.) pulex Leydig, and D. (Ctenodaphnia) magna Straus. In addition, longispina a-like individuals that form a separate phylogenetic lineage was identified.     

Bacterio- and virioplankton in water bodies of a raised bog (Vologda oblast,Russia)

The abundance of virio-and bacterioplankton and the role of viruses in the mortality of heterotrophic bacteria have been studied in three different mire water bodies (lagg, hollow, and stream) in the Shichengskoe raised bog. The abundance of bacteria (up to 93 million cells/mL) and viruses (up to 152 million particles/mL) reached very high values. Considerable differences were found between the mire water bodies in seasonal dynamics and average values of the studied parameters. The ratio of the number of virioplankton to the number of bacterioplankton (median values from 1.3 in a hollow to 5.6 in a stream) is in low ranges of values which are available in literature sources. Viruses did not have a considerable direct effect on bacterioplankton while lysing ≤7.8% of the bacterial production.     

Heliozoa (Centrohelea,Haptista, Hacrobia) of saline and brackish water bodies and watercourses of Russia

The species composition of centrohelid heliozoa (Centrohelida) in saline and brackish inland water bodies and watercourses with salinity 2.0–42.2‰ was studied in the subarid zone of Russia. Nine species (Polyplacocystis ambigua, Pterocystis foliacea, Choanocystis ebelii, Acanthocystis astrakhanensis, A. dentata, A. myriospina, A. pectinata, A. taurica, A. turfacea) are new for saline and brackish inland waters. A. astrakhanensis and A. taurica are new for the fauna of Orenburg region. The first data on centrohelidian fauna in saline rivers of Elton region were obtained. The fauna comprises Polyplacocystis ambigua, Pterocystis foliacea, A. turfacea and Choanocystis ebelii. C. ebelii is new for the protist fauna of Russia. Five species (Polyplacocystis ambigua, Pterocystis foliacea, A. pectinata, A. dentata, A. taurica) were recorded for the first time in saline and brackish waters and described as eurihaline. Morphological diagnoses of Acanthocystis dentata and A. taurica were completed.     

Molecular-phylogenetic analysis of cyclopoids (Copepoda: Cyclopoida) from Lake Baikal and its water catchment basin

Baikalian cyclopoids represent one of the richest endemic faunas of freshwater cyclopoid copepods. The genus Diacyclops Kiefer, 1927 is the most numerous by species number in the lake. In this work, molecular-phylogenetic analysis of 14 species and 1 sub-species from Lake Baikal and its water catchment basin is performed. The regions of mitochondrial cytochrom-oxydase I (COI) and of nuclear small-subunit 18S rRNA were used as evolution markers. In the obtained set of COI gene sequences, an effect of synonymous substitution saturation is revealed. Baikalian representatives of the genus Diacyclops form at phylogenetic schemes by two markers a monophyletic group, it suggest their origin from a common ancestral form. Preliminary estimate of this group age is 20–25 My.     

Biota of Lake Cheder (Tuva,Russia)

The algal flora and invertebrate fauna of Lake Cheder, located in the Central Tuva Basin, Russia, have been studied from collections made in August 1999. Eighteen taxa belonging to diatoms, blue–green and green algae, and seven species of fauna (two crustaceans and five insects) were present.     

Biodiversity,distribution and production of macrozoobenthos communities in the saline Chernavka River (Lake Elton basin,South-West Russia)

Limnology - The rise of salinity of inland waters in many regions of the world highlights the necessity of investigations of ecosystems with a naturally high level of salinity to be able to predict...     

The assessment of water quality in the Artois-Picardie water basin (France) by the use of diatom indices

The performance of six diatom indices to evaluate water quality has been studied in the Artois-Picardie water basin. Results show that all of them satisfactorily assess organic pollution which is the main phenomenon responsible for the degradation of water quality throughout the year. However, only the Specific Pollution Sensitivity Index (SPI), the Generic Diatom Index (GDI) and the Commission of Economical Community Index (CEC) show significant correlations with the ionic strength (expressed by chlorides, sulphates and conductivity) and eutrophication (expressed by chlorophyll and nitrates). Diatom indices do not integrate chemical parameters in the same way. Best correlations are obtained through simultaneous or average chemical analyses whereas for other parameters, best correlations are noted with chemical analyses carried out just before diatom sampling. Tests performed on different chemical data sets show that it is possible to make a realistic estimation of water quality during the summer in the Artois-Picardie water basin by using SPI in September.     

The insight into diatom diversity,ecology, and biogeography of an extreme cold ultraoligotrophic Lake Labynkyr at the Pole of Cold in the northern hemisphere

The freshwater ultraoligotrophic Lake Labynkyr is located near the Pole of Cold in the northern hemisphere (Yakutia, Russia). The lake is covered by ice during 240 days a year. We undertook several expeditions to the lake during the ice and open water periods for sampling ice fouling, plankton and periphyton that were then analyzed by means of scanning electron microscopy. As a result, we identified a high biodiversity of diatoms—123 species and intraspecific taxa from 53 genera, among them 3 species were new for Russia and 26 taxa were new for the algal flora of Yakutia. The oligo- and xenosaprobionts and their variations dominate—71 taxa. 18 Species were evaluated as tolerant to cold oligotrophic waters, 12 occurred on the ice bottom, and 62 in the water column under ice (0–25 m). 104 taxa were found during the open water period, 70 taxa were identified in the periphyton. We showed the diatom flora of Lake Labynkyr to be unique compared with other lakes of Yakutia and to share taxa with the diatom flora of Lake Baikal. The diatoms being indicators of the global climate changes and ecological status of lakes, our data can be used as an evidence of such changes as well as to be useful studies of biogeography and history of formation of flora in Arctic and Subarctic waters.

     

Identifying gray whale (Eschrichtius robustus) foraging grounds along the Chukotka Peninsula, Russia, using satellite telemetry

The purpose of this study was to evaluate summer and fall residency and habitat selection by gray whales, Eschrichtius robustus, together with the biomass of benthic amphipod prey on the coastal feeding grounds along the Chukotka Peninsula. Thirteen gray whales were instrumented with satellite transmitters in September 2006 near the Chukotka Peninsula, Russia. Nine transmitters provided positions from whales for up to 81?days. The whales travelled within 5?km of the Chukotka coast for most of the period they were tracked with only occasional movements offshore. The average daily travel speeds were 23?km?day^?1 (range 9–53?km?day^?1). Four of the whales had daily average travel speeds <1?km?day^?1 suggesting strong fidelity to the study area. The area containing 95% of the locations for individual whales during biweekly periods was on average 13,027?km² (range 7,097–15,896?km²). More than 65% of all locations were in water <30?m, and between 45 and 70% of biweekly kernel home ranges were located in depths between 31 and 50?m. Benthic density of amphipods within the Bering Strait at depths <50?m was on average ~54?g wet wt m^?2 in 2006. It is likely that the abundant benthic biomass is more than sufficient forage to support the current gray whale population. The use of satellite telemetry in this study quantifies space use and movement patterns of gray whales along the Chukotka coast and identifies key feeding areas.     

Ecosystem evolution of Lake Gusinoe (Transbaikal region, Russia)

Lake Gusinoe is situated on a basin originating from Paleozoic and Mesozoic deposits. The recorded history of the lake's ecosystem evolution is no more than 300 years. The present lake drainage basin was formed mainly in the Cenozoic era, but during the past century, major anthropogenic impacts on the lake have occurred. The human-influenced evolution of the ecosystem began in the 1940s with the development of opencut coal mining nearby the lake. Population increase and the building of the Gusinoozersk State Regional Power Plant, the Trans-Mongolian Railroad and an associated station, and military installations were the major sources of anthropogenic impacts. Since the early 1950s about five species of fish have been introduced into Lake Gusinoe or have invaded the lake, and at least six of the native species have disappeared or are in danger of extinction. From our recent investigations, the present environment of the Lake Gusinoe Basin (Gusinoozersk Basin) is divided into four zones hydrogeochemically: (1) ultrafreshwater, (2) freshwater, (3) mineralized water, and (4) hyposaline and saltwater. Some additional data on changes of the chemical components of the drainage basin waters, as well as on the transition of zooplankton and zoobenthic fauna, are presented in consideration of the risk of industrial development, and the perspectives are discussed.     

Sediment diatom assemblages and composition of pore-water dissolved organic matter reflect recent eutrophication history of Lake Peipsi (Estonia/Russia)

A paleolimnological approach was used for the assessment of the recent eutrophication history and identification of possible reference conditions in the large, shallow, eutrophic Lake Peipsi. Lake Peipsi is the fourth largest lake by area, and the largest transboundary lake in Europe, being shared between Estonia and Russia. Lake Peipsi has been anthropogenically impacted over a longer time-scale than that covered by instrumental limnological monitoring. The ²¹⁰Pb record and down-core distribution of fly-ash particles in the 40-cm core from the middle part of the lake suggest 130 years of sediment accumulation. Diatom assemblages indicate alkaline mesotrophic conditions and a well-illuminated water column, sediment pore-water fluorescence index values suggest low autochthonous productivity and a stable aquatic ecosystem similar to natural reference conditions during the second half of 19th and early 20th century. Near-synchronous stratigraphic changes including the expansion of the eutrophic planktonic diatom Stephanodiscus parvus, the appearance of new species associated with eutrophic lakes and the decrease in the relative abundance of littoral diatoms, together with changes in the fluorescence properties of sediment pore-water dissolved organic matter, imply increased nutrient availability, enlarged phytoplankton crops, reduced water-column transparency and the onset of human-induced disturbances in the lake since the mid-20th century. The most conspicuous expansion of eutrophic planktonic diatoms and maximum concentration of siliceous microfossils occur simultaneously with changes in the fluorescence indexes of pore-water dissolved organic matter, indicating a pronounced increase in the contribution of autochthonous organic matter to the lake sediment. This implies that nutrient loading and anthropogenic impact was at a maximum during the 1970s and 1980s. Sedimentary diatom flora may reflect a reduction of phosphorus loading since the 1990s. However, the absolute abundance of planktonic diatoms and sediment pore-water fluorescence index values vary greatly implying that the lake ecosystem is still rather unstable.