The autotrophic picoplankton of Lake Baikal was discovered more than 30 years ago; the productivity of the endemic member of the group, Synechocystis limnetica, is of particular interest. In the course of long-term investigations, the abundance of this species was established using the sedimentation technique. Maximum abundance was reached at 104 cells per ml in summer. In addition to estimating the distribution of this species throughout a defined lake area during the spring-summer period, the character of interrelations with large phytoplankton was revealed.

Baikalian autotrophic picoplankton was studied from 1997 to 2000 using epifluorecsence and scanning electron microscopy. The study of seasonal and annual dynamics of picoplankton abundance was conducted monthly at the monitoring station in southern Baikal. The spatial distribution of autotrophic picoplankton was observed in the period when Lake Baikal was free of ice; the lake area was defined by 50 stations. Microscopic examination of planktonic samples revealed that the phycoerythrin-rich cyanobacteria of genus Synechococcus generated the largest biomass of autotrophic picoplankton in Lake Baikal. Morphotype diversity of the representatives of genus Synechecoccus was revealed in the study: Synechococcus spp. of coccoid and ellipsoid forms were dominant by abundance. The coccoid and ellipsoid forms had diameters of 0.9 and 0.7 to 1.3 μm, respectively. The portion of picoplanktonic algae in the Baikalian picoplankton community is not high and does not exceed 10% in the summer time when growth is highest.

The autotrophic picoplankton abundance throughout the year in the 0–50 m layer varies by more than one hundred times. Maximal concentration of picocyanobacteria occurs in late July–August at 10 to 25 m depths where it reached 106 cells ml−1. The minimal concentration (103 cells ml−1) was observed in December at the same depths. A small peak of the picoplankton growth occurred in April of each year when the total numbers of picocyanobacteria increased 2 to 4 times after winter. In 1999 the peak rose to 105 cells ml−1 . During the investigation period the highest indices of autotrophic picoplankton numbers were observed in 1999 and the lowest in 1997. The spatial distribution of this group in the whole Baikal aquatorium was characteristically heterogeneous; its abundance varied by 2 to 10 times in different parts of the lake. The largest fluctuation occurred in August and the least in September. The maximum picoplankton abundance was observed in the epilimnion during the periods of thermal stratification. In the course of homothermy a comparably homogeneous distribution of picocyanobacteria was revealed up to 300 m depth, but the highest numbers were found in the upper 30 m layer.

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References

Antipova, N. L.
1963
.
Seasonal and annual phytoplankton changes in Lake Baikal
.
Trudy LIN SO RAN
,
22
:
12
28
.
(In Russian)
Atlaschkin, V. V., Belykh, O. L. and Belikov, S. I.
Picoplanktonic green algae from Lake Baikal: Morphology, ultrastructure and rbcL gene sequences
.
Proceedings of a Conference on biodiversity and dynamics of ecosystems in North Eurasia, VS
.
Aug. 21-26 2000
. pp.
158
160
.
Novosibirsk
.
Belykh, O. I., Semenova, E. A., Zaika, E. L., Kiiznedelov, K. D. and Guselnikova, N. E.
2000
.
An eukaiyotic alga from picoplankton of Lake Baikal: Morphology, ultrastructure and rDNA sequence data
.
Hydrobiologia
,
435
:
83
90
.
Belykh, O. I., Zaika, E. I. and Berezikov, E. V.
1999
.
Autotrophic picoplankton of Lake Baikal
.
Sib. J. Ecol.
,
6
:
35
39
.
(In Russian)
Bondarenko, N. A. and Guselnikova, N. E.
1989
.
Primary production of phytoplankton in southern Lake Baikal
.
Izvestia SO RAN USSR, Biol. Sci.
,
1
:
77
80
.
(In Russian)
Boraas, M. E., Bolgrien, D. W. and Holen, D. A.
1991
.
Determination of eubacterial size and cyanobacterial size and number in Lake Baikal using epifluorescence
.
Int. Revue Hydrobiol.
,
76
:
537
544
.
Glazunov, I. V. and Kozhova, O. M.
1966
.
Phytoplankton production determination in shallow-water region of Selenga river
.
Izvestia SO RAN USSR, Biol. Sci.
,
3
:
40
52
.
(In Russian)
Komarek, J.
1976
.
Taxonomic review of the genera Synechocystis Sauv. 1892, Synechococcus Nag. 1849, and Cyanothece gen. nov. (Cyanophyceae)
.
Archiv Protistenkunde
,
118
:
119
179
.
Kozhova, M. M. and Izmesteva, L. R., eds.
1998
.
Lake Baikal. Evolution and Biodiversity
,
Leiden, NL
:
Backhuys Publishers
.
Kuzmin, G. V.
1975
. “
Phytoplankton.
”. In
Procedures of Studying of Biogeocenoses in Inner Waters
, Edited by: Mordukhaj-Boltovskoj, F. D.
83
84
.
Moscow
:
Nauka
.
(In Russian)
Mats, V D.
1993
.
The structure and development of the Baikal rift depression
.
Earth-Science Rev.
,
34
:
81
118
.
Nagata, T., Takai, K., Kawanobe, K., Kim, D.-S., Nakazato, R., Guselnikova, N., Bondarenko, N., Mologawaya, O., Kostmova, T., Drucker, V., Satoh, Y. and Watanabe, Y.
1994
.
Autotrophic picoplankton in southern Lake Baikal: Abundance, growth and grazing mortality during summer
.
J. Plankton Res.
,
16
:
945
959
.
Popovskaya, G. I.
1968a
.
Species nova Synechocystidis Sauv. in plancto lacus Baikal
.
Novitates systematicae plantarum non vascularium
,
5
:
3
5
.
Popovskaya, G. I.
Role of ultrananoplankton in oligotrophic water bodies (example of Lake Baikal)
.
Proceedings of the XIV Conference on study of inner water bodies of Baltic Area
. Edited by: Kraskauskas, I. C. pp.
34
39
.
Riga
.
(In Russian)
Popovskaya, G. I.
1991
. “
Phytoplankton of Lake Baikal and its long-term changes (1958-1990)
”.
Novosibirsk
.
Dissertation in the form of a report. (In Russian)
Popovskaya, G. I.
2000
.
Ecological monitoring of phytoplankton in Lake Baikal
.
Aquat. Ecosyst. Health Manage.
,
3
:
215
225
.
Sendergaard, M.
1991
.
Phototrophic picoplankton in temperate lakes: Seasonal abundance and importance along a trophic gradient
.
Int. Revue Hydrobiol.
,
76
:
545
554
.
Stockner, J. G.
1991
.
Autotrophic picoplankton in freshwater ecosystem: The view from summit
.
Int. Revue Hydrobiol.
,
76
:
595
604
.
Stockner, J. G. and Antia, N. J.
1986
.
Algal picoplankton from marine and freshwater ecosystems: A multidisciplinary perspective
.
Can. J. Fish. Sci.
,
43
:
2472
2503
.
Votintsev, K. K., Mescheryakova, A. I. and Popovskaya, G. I.
1972
.
On the role of ultrananoplanktonic algae in the formation of primary production in Lake Baikal in summer
.
Hydrobiol. J.
,
9
:
21
27
.
(In Russian)
Votintsev, K. K., Mescheryakova, A. I. and Popovskaya, G. I.
1975
.
Cycle of Organic Matter in Lake Baikal
,
Novosibirsk
:
Nauka
.
(In Russian)
Watanabe, Y. and Drucker, V.
1999
. “
Phytoplankton blooms in Lake Baikal, with reference to the lake's present state of eutrophication.
”. In
Ancient Lakes: Their Cultural and Biological Diversity
, Edited by: Kawanabe, H., Coulter, G. W. and Rosewalt, A. C.
217
225
.
Belgium
:
Kenobi Productions
.
Weisse, T. and Kenter, U.
1991
.
Ecological characteristics of autotrophic picoplankton in a Prealpine Lake
.
Int. Revue Hydrobiol.
,
76
:
545
554
.