Densities and distribution of flagellates and ciliates in the chemocline of saline, meromictic Lake Shunet (Siberia, Russia)

Khromechek, Elena B.; Barkhatov, Yuri V.; Rogozin, D. Yu.

doi:10.1007/s10452-010-9332-x

Cited by 19 publications

(7 citation statements)

References 52 publications

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“…Data on Cryptomonas spp. and ciliates are obtained on 27 July 2005 from the same samples (Khromechek et al 2010) habitat. Having been recently established in the middle of the Siberian sub-continent, and with very high salt content and water chemistry that is very different from that of the sea water, the lakes have little chances to be inhabited by either freshwater or sea species.…”

Section: Resultsmentioning

confidence: 99%

“…and their common ciliate predator genera (Oligotrichida, Scuticociliatida, Hypotrichida and Prostomatida) (Khromechek et al 2010) are adapted to poor light conditions, anoxia and hydrogen sulphide in the lake. The population of Cryptomonas sp.…”

Section: Stratification Of Phytoflagellates and Ciliatesmentioning

confidence: 99%

“…We follow it up with the phototrophic sulphur bacteria (PSB), which inhabit the chemocline (Rogozin et al 2010a). Further, we will discuss the importance of phytoflagellates and ciliates, which also tend to concentrate near the gradients of salinity and water density in our ecosystems (Khromechek et al 2010). Moving along the trophic chain, we will discuss the vertical distribution of phytoplankton and factors that determine their vertical distribution.…”

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Vertical stratification of physical, chemical and biological components in two saline lakes Shira and Shunet (South Siberia, Russia)

et al. 2010

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A feature of meromictic lakes is that several physicochemical and biological gradients affect the vertical distribution of different organisms. The vertical stratification of physical, chemical and biological components in saline, fishless meromictic lakes Shira and Shunet (Siberia, Russia) is quite different mainly because both mean depth and maximum depth of lakes differ as well as their salinity levels differ. The chemocline of the Lake Shira, as in many meromictic lakes, is inhabited by bacterial community consisting of purple sulphur and heterotrophic bacteria. As the depth of the chemocline is variable, the bacterial community does not attain high densities. The mixolimnion in Lake Shira, which is thermally stratified in summer, also creates different habitat for various species. The distribution of phytoplankton is non-uniform with its biomass peak in the metalimnion. The distribution of zooplankton is also heterogeneous with rotifers and juvenile copepods inhabiting the warmer epilimnion and older copepods found in the cold but oxic hypolimnion. The amphipod Gammarus lacustris which can be assigned to the higher trophic link in the fishless lake's ecosystem, such as Lake Shira, is also distributed non-uniformly, with its peak density generally observed in the thermocline region. The chemocline in Lake Shunet is located at the depth of 5 m, and unlike in Lake Shira, due to a sharp salinity gradient between the mixolimnion and monimolimnion, this depth is very stable. The mixolimnion in Lake Shunet is relatively shallow and the chemocline is inhabited by (1) an extremely dense bacterial community; (2) a population of Cryptomonas sp.; and (3) ciliate community comprising several species. As the mixolimnion of Lake Shunet is not thermally stratified for long period, the phytoplankton and zooplankton populations are not vertically stratified. The gammarids, however, tend to concentrate in a narrow layer located 1-2 m above the chemocline. We believe that in addition to vertical inhomogeneities of both physicochemical parameters, biological and physical factors also play a role in maintaining these inhomogeneities. We conclude that the 123Aquat Ecol (2010) 44:619-632 DOI 10.1007 stratified distributions of the major food web components will have several implications for ecosystem structure and dynamics. Trophic interactions as well as mass and energy flows can be significantly impacted by such heterogeneous distributions. Species spatially separated even by relatively short distances, say a few centimetres will not directly compete. Importantly, we demonstrate that not only bacteria, phytoflagellates and ciliate tend to concentrate in thin layers but also larger-sized species such Gammarus (amphipods) can also under certain environmental conditions have stratified distribution with maxima in relatively thin layer. As the vertical structure of the lake ecosystem is rather complex in such stratified lakes as ours, the strategy of research, including sampling techniques, should consider potentially var...

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Section: Resultsmentioning

confidence: 99%

Section: Stratification Of Phytoflagellates and Ciliatesmentioning

confidence: 99%

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Vertical stratification of physical, chemical and biological components in two saline lakes Shira and Shunet (South Siberia, Russia)

et al. 2010

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“…and mixotrophic flagellates Cryptomonas sp. (up to 10 5 cells ml -1 ; Khromechek et al 2010). In both lakes, the dominant species of pelagic zooplankton are the calanoid copepod Arctodiaptomus salinus and several rotifer species (Anufrieva 2006;Zadereev and Tolomeev 2007).…”

Section: Methodsmentioning

confidence: 98%

The vertical distribution and abundance of Gammarus lacustris in the pelagic zone of the meromictic lakes Shira and Shunet (Khakassia, Russia)

et al. 2010

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The vertical distribution and abundance of Gammarus lacustris in the pelagic zone of two fishless meromictic lakes, L. Shira and L. Shunet, in Southern Siberia (Russia), was studied with the underwater video recording system and using vertical hauls. In both lakes, during summer stratification, Gammarus was distributed non-homogenously, with a stable peak in the metalimnion. The average depth of Gammarus population in the pelagic zone was significantly correlated with the depth of the thermocline. Gammarus abundances obtained using vertical plankton hauls with net were quite comparable with those obtained from video records. The peak abundance of Gammarus in the pelagic zone of the lakes observed with underwater video amounted up to 400 individuals m -2 , while the peak animal densities in the metalimnion reached 50 ind. m -3 . The data are compared with previously published abundances of Gammarus in the littoral of Lake Shira. Both littoral and pelagic can be equally important habitats for amphipods in meromictic lakes. The absence of fish in the pelagic zone, high oxygen concentration, low water temperature, increased seston concentration, elevated water density in the metalimnion and the anoxic hypolimnion can be the most probable combination of factors that are responsible for the peak of Gammarus in the metalimnion of these lakes.

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“…The limnological characteristics of Lakes Shira and Shunet, including ecological modeling, characterization of environmental factors, elemental cycles with temporal and spatial variations, and surveys of flora and fauna, have been reported [ 9 , 20 , 21 , 28 – 30 ]. Physicochemical properties, water color, etc., were direct evidence for stratification.…”

Section: Introductionmentioning

confidence: 99%

Bacterial Communities of Three Saline Meromictic Lakes in Central Asia

et al. 2016

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Meromictic lakes located in landlocked steppes of central Asia (~2500 km inland) have unique geophysiochemical characteristics compared to other meromictic lakes. To characterize their bacteria and elucidate relationships between those bacteria and surrounding environments, water samples were collected from three saline meromictic lakes (Lakes Shira, Shunet and Oigon) in the border between Siberia and the West Mongolia, near the center of Asia. Based on in-depth tag pyrosequencing, bacterial communities were highly variable and dissimilar among lakes and between oxic and anoxic layers within individual lakes. Proteobacteria, Bacteroidetes, Cyanobacteria, Actinobacteria and Firmicutes were the most abundant phyla, whereas three genera of purple sulfur bacteria (a novel genus, Thiocapsa and Halochromatium) were predominant bacterial components in the anoxic layer of Lake Shira (~20.6% of relative abundance), Lake Shunet (~27.1%) and Lake Oigon (~9.25%), respectively. However, few known green sulfur bacteria were detected. Notably, 3.94% of all sequencing reads were classified into 19 candidate divisions, which was especially high (23.12%) in the anoxic layer of Lake Shunet. Furthermore, several hydro-parameters (temperature, pH, dissolved oxygen, H2S and salinity) were associated (P< 0.05) with variations in dominant bacterial groups. In conclusion, based on highly variable bacterial composition in water layers or lakes, we inferred that the meromictic ecosystem was characterized by high diversity and heterogenous niches.

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Densities and distribution of flagellates and ciliates in the chemocline of saline, meromictic Lake Shunet (Siberia, Russia)

Cited by 19 publications

References 52 publications

Vertical stratification of physical, chemical and biological components in two saline lakes Shira and Shunet (South Siberia, Russia)

Vertical stratification of physical, chemical and biological components in two saline lakes Shira and Shunet (South Siberia, Russia)

The vertical distribution and abundance of Gammarus lacustris in the pelagic zone of the meromictic lakes Shira and Shunet (Khakassia, Russia)

Bacterial Communities of Three Saline Meromictic Lakes in Central Asia

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