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Tamara V. Khodzher - One of the best experts on this subject based on the ideXlab platform.
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Ionic Composition of Water in Lake Baikal, Its Tributaries, and the Angara River Source during the Modern Period
Russian Meteorology and Hydrology, 2019Co-Authors: V. M. Domysheva, M. V. Sakirko, L. M. Sorokovikova, V. N. Sinyukovich, N. A. Onishchuk, I. V. Tomberg, N.a. Zhuchenko, L. P. Golobokova, Tamara V. KhodzherAbstract:The results of long-term routine measurements of the concentration of major ions in the water of the Lake Baikal Pelagic Zone, the Angara River source, and main tributaries of the lake are analyzed. The average values of ion concentration in the water column of the lake and in the Angara River obtained for the recent decade are presented and compared with the data of previous studies. Long-term trends in the concentration of ions in the main Baikal tributaries are shown. Under low-water conditions, the inflow of ions to Lake Baikal through tributaries decreases despite an increase in their concentration in river water. Changes in the chemical composition of water in the tributaries did not affect the ionic composition of water in the Lake Baikal Pelagic Zone and in the Angara River source.
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Current chemical composition of Lake Baikal water
Inland Waters, 2017Co-Authors: Tamara V. Khodzher, V. M. Domysheva, L. M. Sorokovikova, Maria V. Sakirko, I. V. TombergAbstract:AbstractHabitats of organisms in Lake Baikal have been comprehensively monitored for many years. In 2010–2015, we conducted 8 research expeditions to study ionic composition of the water and measure concentrations of dissolved oxygen, nutrients, organic carbon, and persistent organic pollutants in the entire Pelagic area of Lake Baikal. Our data showed that the ionic composition was stable at all depths in the Pelagic Zone of the lake. We also recorded seasonal variability, vertical stratification, and spatial variations in the content of nutrients, organic matter, and gas components. The concentrations of major ions, nutrients, and dissolved oxygen were favourable for the growth of hydrobionts in the offshore Pelagic Zone. Concentrations of pollutants in Lake Baikal, such as persistent organic pollutants and heavy metals, were low and did not directly affect the biota. The water in specific areas of the littoral Zone of Lake Baikal, however, was polluted near large settlements (Listvyanka, Severobaikalsk...
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The spring phytoplankton in the Pelagic Zone of Lake Baikal during 2007‒2011
Geography and Natural Resources, 2015Co-Authors: G. I. Popovskaya, Marina Usoltseva, V. M. Domysheva, M. V. Sakirko, V. V. Blinov, Tamara V. KhodzherAbstract:An assessment is made of the current status of the phytoplankton in the Pelagic Zone of Lake Baikal for 2007‒2011, as the continuation of previous long-term research. We investigated the species composition, population, biomass and spatial distribution of the phytoplankton in the Pelagic Zone of Baikal. Its quantitative indicators for 2007‒2011 have been compared with data of long-term investigations (1964‒1990). It is shown that the species composition of the phytoplankton remained stable at different periods. The values of population and biomass for 2007‒2011 fitted in the range of long-term fluctuations (1964‒1990), with the species assemblage characteristic for that period. As in the case with previous research, the main contribution to the biomass of the spring phytoplankton in the lake was made by the diatoms Aulacoseira baicalensis, Synedra acus subsp. radians, Aulacoseira islandica, and Stephanodiscus meyeri. Their maximum and minimum concentrations were observed in the southern and middle lake depressions, and in Northern Baikal, respectively. The study revealed a correlation of phytoplankton biomass with silicon concentration; no correlation with nitrates, phosphates and temperature was ascertained.
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the spring phytoplankton in the Pelagic Zone of lake baikal during 2007 2011
Geography and Natural Resources, 2015Co-Authors: G. I. Popovskaya, Marina Usoltseva, V. M. Domysheva, M. V. Sakirko, V. V. Blinov, Tamara V. KhodzherAbstract:An assessment is made of the current status of the phytoplankton in the Pelagic Zone of Lake Baikal for 2007‒2011, as the continuation of previous long-term research. We investigated the species composition, population, biomass and spatial distribution of the phytoplankton in the Pelagic Zone of Baikal. Its quantitative indicators for 2007‒2011 have been compared with data of long-term investigations (1964‒1990). It is shown that the species composition of the phytoplankton remained stable at different periods. The values of population and biomass for 2007‒2011 fitted in the range of long-term fluctuations (1964‒1990), with the species assemblage characteristic for that period. As in the case with previous research, the main contribution to the biomass of the spring phytoplankton in the lake was made by the diatoms Aulacoseira baicalensis, Synedra acus subsp. radians, Aulacoseira islandica, and Stephanodiscus meyeri. Their maximum and minimum concentrations were observed in the southern and middle lake depressions, and in Northern Baikal, respectively. The study revealed a correlation of phytoplankton biomass with silicon concentration; no correlation with nitrates, phosphates and temperature was ascertained.
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Seasonal dynamics of primary production in the Pelagic Zone of southern Lake Baikal
Limnology, 2003Co-Authors: Takehito Yoshida, Tamara V. Khodzher, N. G. Melnik, Tatsuki Sekino, Motomi Genkai-kato, Natalia P. Logacheva, N. A. Bondarenko, Shuji Hino, Zen'ichiro Kawabata, Kentaro NozakiAbstract:We measured primary production by phytoplankton in the south basin of Lake Baikal, Russia, by in situ 13C-bicarbonate incubations within the period March–October in two consecutive years (1999 and 2000). Primary production was highest in the subsurface layer, possibly due to near-surface photoinhibition of photosynthesis, even under 0.8 m of ice cover in March. Areal primary production varied from 79 mg C m−2 day−1 (March) to 424 mg C m−2 day−1 (August), and annual primary production was roughly estimated as 75 g C m−2 year−1, both of which are within the lower range of previous estimates. Size fractionation measurements revealed that phytoplankton in the
Jukka Horppila - One of the best experts on this subject based on the ideXlab platform.
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Seasonal fluctuations in macrophyte cover and water transparency of four brown-water lakes: implications for crustacean zooplankton in littoral and Pelagic habitats
Hydrobiologia, 2008Co-Authors: Satu Estlander, Leena Nurminen, Mikko Olin, Mika Vinni, Jukka HorppilaAbstract:The dynamics of crustacean zooplankton in the littoral and Pelagic Zones of four forest lakes having variable water qualities (colour range 130–340 mg Pt l−1, Secchi depth 70–160 cm) were studied. The biomass of zooplankton was higher in the littoral Zone than in the Pelagic Zone only in the lake having the highest transparency. In the three other lakes, biomass was significantly higher in the Pelagic Zone than in the littoral Zone. In the two lakes with highest transparency, the littoral biomass of cladocerans significantly followed the development of macrophyte vegetation, and cladoceran biomass reached the maximum value at the time of highest macrophyte coverage. In lakes with lowest transparency, littoral zooplankton biomass developed independently of macrophyte density and decreased when macrophyte beds were densest. The seasonal development of the littoral copepod biomass did not follow the development of macrophytes in any of the lakes. The mean size of cladocerans in the Pelagic Zone decreased with increasing Secchi depth of the lake, whereas in the littoral Zone no such phenomenon was detected. Seasonally, when water transparency increased temporarily in two of the lakes, the mean size of cladocerans in the Pelagic Zone decreased steeply. For copepods, no relationship between water transparency and body size was observed. The results suggested that in humic lakes the importance of the littoral Zone as a refuge decreases with decreasing transparency of the water and that low water transparency protects cladocerans from fish predation. All the observed between-lake differences could not be explained by fish predation, but were probably attributed to the presence of chaoborid larvae with variable densities. Feeding efficiency of chaoborids is not affected by visibility and thus they can obscure the relationship between water quality, fish density, and the structure of crustacean zooplankton assemblages.
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Seasonal changes in the diets and relative abundances of perch and roach in the littoral and Pelagic Zones of a large lake
Journal of Fish Biology, 2000Co-Authors: Jukka Horppila, Jukka Ruuhijärvi, Martti Rask, C. Karppinen, Kari Nyberg, Mikko OlinAbstract:In the Enonselka and Laitialanselka basins of Lake Vesijarvi, perch Perca fluviatilis and roach Rutilus rutilus were abundant in the littoral and in the Pelagic Zones throughout the summer. In the littoral Zone, roach was always more numerous than perch, while perch dominated in the open water. Intraspecific diet overlap values were higher than interspecific values. In the Pelagic Zone, perch
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the diet and growth of roach rutilus rutilus l in lake vesijarvi and possible changes in the course of biomanipulation
Hydrobiologia, 1994Co-Authors: Jukka HorppilaAbstract:Previous studies have suggested that the roach Rutilus rutilus (L.) stock of Lake Vesijarvi is one of the main factors delaying the recovery of the lake after sewage diversion. This study is concerned with the documentation of the diet of roach in the lake. In total, 531 roach were examined. Both in the pelagial and in the littoral the roach had mixed diets in May and in September—October. The importance of zooplankton decreased and the importance of benthos and plants increased with increasing size of roach. In July, in the Pelagic Zone all sizes of roach fed exclusively on zooplankton (Bosmina spp.), while in the littoral zooplankton had the highest volume proportions only in the smallest (<130 mm) roach. The frequent use of plant food and slow growth rate of large roach indicate a low availability of animal prey. As the fish densities decrease due to the mass removal taking place in the lake, the percentage of plant food in the diets of roach will probably decrease and the growth of roach will increase. Additionally, the tendency of the roach to migrate into the Pelagic Zone in early summer may be reduced, which would decrease their predation on the zooplankton.
Martin Søndergaard - One of the best experts on this subject based on the ideXlab platform.
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Bacterioplankton in the littoral and Pelagic Zones of subtropical shallow lakes
Hydrobiologia, 2010Co-Authors: David Da Motta Marques, Erik Jeppesen, Martin SøndergaardAbstract:We measured bacterioplankton (phylotypes detected by fluorescent in situ hybridisation, morphometric forms, abundance and production) in samples collected in summer in the littoral and Pelagic Zones of 10 subtropical shallow lakes of contrasting area (from 13 to 80,800 ha). Compared to the Pelagic Zones, the littoral Zones were overall characterised by higher macrophyte dominance and lower concentrations of total phosphorus and alkalinity and higher concentrations of dissolved organic carbon (DOC) and humic substances. Similarities of bacterial production and biomass turnover and density of active phylotypes and morphotype proportions were related to similarities in a set of environmental variables (including nutrients, humic substances content, predator density and phytoplankton biomass), and some additionally to lake area. Horizontal heterogeneity in bacterioplankton variables (littoral versus Pelagic) increased with lake area. Bacterioplankton biomass and production tended to be lower in the littoral Zone than in the Pelagic Zone despite higher concentrations of DOC and humic substances. A likely explanation is higher predation on bacterioplankton in the littoral Zone, although allelophatic effects exerted by macrophytes cannot be excluded. Our results indicate that organic cycling via bacterioplankton may be less efficient in the littoral Zone than in the Pelagic Zone of shallow lakes.
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pike esox lucius l stocking as a biomanipulation tool 1 effects on the fish population in lake lyng denmark
Hydrobiologia, 1997Co-Authors: Soren Berg, Erik Jeppesen, Martin SøndergaardAbstract:From 1990–1993 juvenile pike (Esox lucius)were stocked each spring in the eutrophic Lake Lyng (9.9 ha, max. depth 7.6 m, mean depth 2.4 m) in densities between 515 and 3616 pike ha–1. In 1989-90 the fish population consisted mainly of roach (Rutilus rutilus),rudd (Scardinius erythrophthalmus),perch (Perca fluviatilis)and ruffe (Gymnocephalus cernuus),and total fish biomass was estimated at 477 kg ha–1. Prior to stocking pike was not present in the lake. Following the first year of stocking, the density of roach, rudd and ruffe fry expressed as catch per unit effort decreased significantly by 64 to 97%. In 1991 ruffe disappeared completely. The pike stocking did not affect the density of perch significantly. The growth of pike was high and also the growth of perch increased significantly from 1990 to 1991 (p 0.4). Pike survival was low in late August/early September. We suggest that growth of the piscivorous perch increased due to increased Secchi depth and a continuous high density of 0+ planktivores in the Pelagic Zone of the lake during the years of pike stocking, possibly caused by behaviourial changes and the forcing of the 0+ planktivores into the Pelagic Zone.
V. M. Domysheva - One of the best experts on this subject based on the ideXlab platform.
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Ionic Composition of Water in Lake Baikal, Its Tributaries, and the Angara River Source during the Modern Period
Russian Meteorology and Hydrology, 2019Co-Authors: V. M. Domysheva, M. V. Sakirko, L. M. Sorokovikova, V. N. Sinyukovich, N. A. Onishchuk, I. V. Tomberg, N.a. Zhuchenko, L. P. Golobokova, Tamara V. KhodzherAbstract:The results of long-term routine measurements of the concentration of major ions in the water of the Lake Baikal Pelagic Zone, the Angara River source, and main tributaries of the lake are analyzed. The average values of ion concentration in the water column of the lake and in the Angara River obtained for the recent decade are presented and compared with the data of previous studies. Long-term trends in the concentration of ions in the main Baikal tributaries are shown. Under low-water conditions, the inflow of ions to Lake Baikal through tributaries decreases despite an increase in their concentration in river water. Changes in the chemical composition of water in the tributaries did not affect the ionic composition of water in the Lake Baikal Pelagic Zone and in the Angara River source.
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Current chemical composition of Lake Baikal water
Inland Waters, 2017Co-Authors: Tamara V. Khodzher, V. M. Domysheva, L. M. Sorokovikova, Maria V. Sakirko, I. V. TombergAbstract:AbstractHabitats of organisms in Lake Baikal have been comprehensively monitored for many years. In 2010–2015, we conducted 8 research expeditions to study ionic composition of the water and measure concentrations of dissolved oxygen, nutrients, organic carbon, and persistent organic pollutants in the entire Pelagic area of Lake Baikal. Our data showed that the ionic composition was stable at all depths in the Pelagic Zone of the lake. We also recorded seasonal variability, vertical stratification, and spatial variations in the content of nutrients, organic matter, and gas components. The concentrations of major ions, nutrients, and dissolved oxygen were favourable for the growth of hydrobionts in the offshore Pelagic Zone. Concentrations of pollutants in Lake Baikal, such as persistent organic pollutants and heavy metals, were low and did not directly affect the biota. The water in specific areas of the littoral Zone of Lake Baikal, however, was polluted near large settlements (Listvyanka, Severobaikalsk...
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The spring phytoplankton in the Pelagic Zone of Lake Baikal during 2007‒2011
Geography and Natural Resources, 2015Co-Authors: G. I. Popovskaya, Marina Usoltseva, V. M. Domysheva, M. V. Sakirko, V. V. Blinov, Tamara V. KhodzherAbstract:An assessment is made of the current status of the phytoplankton in the Pelagic Zone of Lake Baikal for 2007‒2011, as the continuation of previous long-term research. We investigated the species composition, population, biomass and spatial distribution of the phytoplankton in the Pelagic Zone of Baikal. Its quantitative indicators for 2007‒2011 have been compared with data of long-term investigations (1964‒1990). It is shown that the species composition of the phytoplankton remained stable at different periods. The values of population and biomass for 2007‒2011 fitted in the range of long-term fluctuations (1964‒1990), with the species assemblage characteristic for that period. As in the case with previous research, the main contribution to the biomass of the spring phytoplankton in the lake was made by the diatoms Aulacoseira baicalensis, Synedra acus subsp. radians, Aulacoseira islandica, and Stephanodiscus meyeri. Their maximum and minimum concentrations were observed in the southern and middle lake depressions, and in Northern Baikal, respectively. The study revealed a correlation of phytoplankton biomass with silicon concentration; no correlation with nitrates, phosphates and temperature was ascertained.
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the spring phytoplankton in the Pelagic Zone of lake baikal during 2007 2011
Geography and Natural Resources, 2015Co-Authors: G. I. Popovskaya, Marina Usoltseva, V. M. Domysheva, M. V. Sakirko, V. V. Blinov, Tamara V. KhodzherAbstract:An assessment is made of the current status of the phytoplankton in the Pelagic Zone of Lake Baikal for 2007‒2011, as the continuation of previous long-term research. We investigated the species composition, population, biomass and spatial distribution of the phytoplankton in the Pelagic Zone of Baikal. Its quantitative indicators for 2007‒2011 have been compared with data of long-term investigations (1964‒1990). It is shown that the species composition of the phytoplankton remained stable at different periods. The values of population and biomass for 2007‒2011 fitted in the range of long-term fluctuations (1964‒1990), with the species assemblage characteristic for that period. As in the case with previous research, the main contribution to the biomass of the spring phytoplankton in the lake was made by the diatoms Aulacoseira baicalensis, Synedra acus subsp. radians, Aulacoseira islandica, and Stephanodiscus meyeri. Their maximum and minimum concentrations were observed in the southern and middle lake depressions, and in Northern Baikal, respectively. The study revealed a correlation of phytoplankton biomass with silicon concentration; no correlation with nitrates, phosphates and temperature was ascertained.
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Spatial distribution of carbon dioxide fluxes, biogenic elements, and phytoplankton biomass in the Pelagic Zone of Lake Baikal in spring period of 2010–2012
Atmospheric and Oceanic Optics, 2014Co-Authors: V. M. Domysheva, G. I. Popovskaya, Marina Usoltseva, M. V. Sakirko, D. A. Pestunov, M. N. Shimaraev, Mikhail V. PanchenkoAbstract:The paper presents the measurements of concentrations of oxygen, biogenic elements, phytoplankton biomass, and partial pressures of carbon dioxide in water and the near-water atmosphere in the Pelagic Zone of Lake Baikal in June, 2010–2012. Very contrasting weather conditions were observed in the region in winter-spring months of 2010–2012, which largely determined the character of hydrologic and biologic processes in the Pelagic water Zone of Baikal. The cardinal difference in weather conditions before expeditions of 2010–2012 made it possible to estimate a wide range of interannual variations in these characteristics and to analyze their role in the formation of fluxes at different stages of springtime warming on the basis of three datasets. The quantitative characteristics of phytoplankton biomass are compared with the difference in partial pressure of carbon dioxide in the air-water system.
M. I. Malin - One of the best experts on this subject based on the ideXlab platform.
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Changes in autumn zooplankton in the Pelagic Zone of Lake Sevan (Armenia) during the increase in fish abundance
Inland Water Biology, 2016Co-Authors: A. V. Krylov, A. O. Hayrapetyan, S. E. Bolotov, Yu. V. Gerasimov, M. I. Malin, D. B. Kosolapov, A. A. HovsepyanAbstract:The qualitative composition and structure of the autumn zooplankton in the Pelagic Zone of Lake Sevan in years that were characterized by different abundancies of fish are described. In October 2013, upon the increase in whitefish abundance, the species richness of zooplankton increased insignificantly; the values of the trophic coefficient and the Shannon index, calculated by the number, increased; and the specific number of Rotifera and Cladocera decreased. At the same time, atypical changes were recorded in the development parameters of zooplankton invertebrates. They were expressed as an increase in the total biomass due to Cladocera, among which large Daphnia (Ctenodaphnia) magna Straus occupied the leading position. The possible reasons for the particular changes in zooplankton are discussed.
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Changes in the structural parameters of the summer zooplankton in the Pelagic Zone of Lake Sevan (Armenia) during an increase in fish abundance and biomass
Inland Water Biology, 2016Co-Authors: A. V. Krylov, A. O. Hayrapetyan, Yu. V. Gerasimov, M. I. MalinAbstract:Features of the composition and structure of the summer zooplankton in the Pelagic Zone of Lake Sevan in years that were characterized by different abundances and biomasses of fish are described. It is shown that the species diversity of the community and the specific number of species of zooplankteurs, the quantity of Copepods in the total abundance and biomass of zooplankton, as well as the value of the Shannon index and the trophic coefficient, increased upon an increase in the fish abundance. At the same time, the total biomass of zooplankton and biomass of cladocerans decreased, among which the density and biomass of the larger and more colored Daphnia (Ctenodaphnia) magna Straus decreased, but the density and biomass of D. (Daphnia) hyalina Leydig and Diaphаnosoma brachyurum Lievin increased.