Hidrológiai Közlöny 2008 (88. évfolyam)

6. szám - IL. Hidrobiológus Napok: „A Balaton és vízrendszere – a Balaton-kutatás története” és „A Duna-kutatás története” Tihany, 2007. október 3–5.

11 Gocke K. & Lenz J. (2004): A new turbulence incubator for measuring primary production in non-stratified waters. - J. Plankton. Res. 26/3:357-369. Herodek, S. & Tamás, G. (1976): A fitoplankton tömege, termelése és a Balaton eutrofizálódása. - Hidrológiai Közlöny 56: 219-228. Maclntyre, S. (1993): Vertical mixing in a shallow eutrophic lake: possible consequences for the light climate of phytoplankton. Limnol. Oceanogr. 38: 798-817. Maestrini, S. Y., Sournia, A. & Herbland, A. (1993): Measuring phytoplankton production in 1992 and the coming years: a dilemma? ICES mar. Sei. Symp. 197: 244-259. Marra J. (1978): Phytoplankton photosynthetic response to vertical movement in a mixed layer. - Mar. Biol. 46: 203-208, Nixdorf, B. & Behrendt H. (1991): Discrepancies between 0

2 and 1

4Cmethod resulting from measurements of primary production under consideration of vertical mixing in a shallow eutrophic lake. - Ver. Limnol. 24: 1268-1271. Nixdorf, B., Behrendt, H. & Stellmacher, R. (1990): Comparison of methods for estimation of integral primary production in shallow aquaPhytoplankton photosynthesis under variable light regime Agyi, Á. Vanyovszki, J.', Fodorpataki, L. ', Somogyi, B.

2 , Vörös, L.

2 'University Babe$-Bolyai, Kolozsvár - Balaton Limnological Institute oh the HAS, Tihany Abstract: In natural environments, phytoplankton cells continuously experience light variations due to the vertical displacement of cells within the water column due to hydrodynamics. The common method of the determination of primary production is the static incubation, when phytoplankton cells are exposed to constant light conditions. The in situ and laboratory measurement of planktonic primary production in Lake Balaton has been made so far only by static incubation. Therefore we compared the static and the dynamic incubation methods of the measurement of primary production in Siófok-basin of Lake Balaton in August 2007. The dynamic incubation was done by an elevator operated with a steppermotor. In sunny weather the UV radiance in the nature inhibited the photosynthesis of phytoplankton, therefore the laboratory incubation without UV light overestimated the primary production. In cloudy weather, however, the lower natural UV radiance stimulated the photosynthesis. Significant differences have not been found between the results of the in situ dynamic and in situ static incubation. According to our results, the laboratory incubation method is suitable to estimate the algal primary production, however the in situ dynamic method is the best way to measure it, if the determination of photosynthesis-irradiance curve is not required. Key words: phytoplankton, photosynthesis, static incubation, dynamic incubation, photosynthetron tic ecosystems with special regard to turbulent mixing. - Limnologica 20: 53-56 NixdorJ

; B.. Pagenkopf, W. G. & Behrendt, H. (1992): Diurnal patterns of mixing depth and its influence on primary production in a shallow lake. - Int. Revue ges. Hydrobiol. 77: 349-360. Pálffy, K. & Vörös, L. (2003): Effect of ultraviolet radiation on phytoplankton primary production in Lake Balaton. - Hydrobiologia 506-509: 289-295. Randall, J. M. & Day, J. W. (1984): Effects of river discharge and vertical circulation on aquatic primary production in a turbid Lousiana (USA) estuary. - Neth. J. Sea Res. 21:231 -242 Somogyi, B., Vanyovszki, J., Agyi, A. & Vörös, L. (2007): Eukarióta és prokarióta pikoalaga törzsek fotoszintézisének összehasonlító vizsgálata. - Hidrológiai közlöny 87: 119-121. Vörös L„ Kovács A. & V.-Balogh K. (2003): A fitoplankton és a fitobentosz változásainak kutatása. - A Balaton kutatásának 2002. évi eredményei. (Mahunka S. & Banczerowski J. szerk.) Magyar Tudományos Akadémia, Budapest 9-17. Klossy Irén alkotása