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all stations (Table 5). Since ACT efficiently incorporated organic substrates, the LNA fraction represented a highly active component of bacterial assemblages. At Stns Dam and Middle, the dynamics of CF also correlated with the population of CTC+ cells and an enhanced extracellular phytoplankton production (Table 5). Table 5: Pearson’s correlation coefficients between relative abundances (as percent of DAPI-stained cells) of Betaproteobacteria (%BET), Cytophaga-Flavobacteria (%CF), and Actinobacteria (%ACT) and percentages of cells with an intact membrane (%live), high nucleic acid content (%HNA), high respiratory activity (%CTC+), bacterial production (BP), and extracellular phytoplankton production (EPP). *p
4 LAKES 4.1 Microbial loop components in the oxic/anoxic boundary in stratified lakes M. Macek (mirek@campus.iztacala.unam.mx) compared the autotrophic picoplankton, APP (epifluorescence microscopy and flow-cytometry) and ciliate, CIL (DAPI staining and quantitative protargol staining) distribution monitored in lake Alchichica, Mexican Plateau, Mexico (with Fernando Bautista, UNAM, Mexico) with the data obtained in meromictic lakes Waldsee, Lausitia, Germany (with Brigitte Nixdorf, Brandenburg Technical University, Cottbus, Germany) and Laguna de la Cruz, Cuenca, Spain (with Antonio Picazo y Antonio Camacho, University of Valencia, Burjassot, Valencia, Spain). Despite very big differences in lake limnology (alkaline, deep and warm-monomictic Alchichica vs. karstic meromictic La Cruz and shallow, iron meromictic Waldsee) the anoxic boundary showed a very similar pattern. APP were found in elevated concentrations in the oxycline of the three lakes (between 10 5 to 10 7 cells ml –1 ). We studied fine-scale stratification (0.25 m) of microaerophilic to anaerobic ciliate assemblages along with an estimation of the impact of grazing upon picocyanobacteria in Laguna de la Cruz (PCY), using fluorescently labelled bacteria (FLB) method. Scuticociliates dominated the environment: the genus Ctedoctema (up 130 cells ml –1 ; feeding upon PCY) was present within a wide range of dissolved oxygen concentrations (DO) while Uronema, Sathrophilus (Sphenostomella) and Cristigera strictly followed the DO gradient. Mesodinium sp. (up 20 cells ml –1 ), Monodinium sp. and Askenasia sp. were observed in the mixolimnion. The mixotrophic genera Coleps (20 cells ml –1 ) and Pelagothrix (Prorodon; up 28 cells ml –1 ) along with Spirostomum teres (feeding upon PCY; up 12 cells ml –1 ) biomass-dominated the mixolimnion and oxycline, respectively. In the anaerobic monimolimnion, the genera Holophrya, Caenomorpha and odontostomatids were present. Ciliates containing vacuoles with PCY also fed upon DTAF pre-stained Aeromonas which mimicked the natural PCY size distribution; however, larger cultured PCY of lake origin were not ingested. Zoochlorellabearing ciliates did not ingest FLB at all. Microaerophilic scuticociliates fed upon FLB even in the assays with untreated water samples but Spirostomum teres actively fed only in anaërostat assays (bubbling with helium was used to minimize DO). S. teres feeding rates were not linearly proportional to the incubation time. This non-linearity was in concordance with the observed pattern of vacuole formation: FLB had been quickly collected into very small vacuoles (with only 1–3 bacteria during the first 5–10 min exposition) and these small vacuoles then moved through the cell and finally joined large vacuoles in the posterior end of the cell (Fig. 4). Even though FLB ingestion dropped during the feeding experiment, FLB persisted in vacuoles for more than one hour. Feeding vacuoles were coloured orange (the colour of the PCY isolate used in experiments) with bright red fluorescence upon green excitation light. Combined use of PCY-photosynthesis products and digestion in the anaerobic conditions with an optimum light for PCY activity is hypothesized, a process similar to supposed oxygen- and primary production of Pelagothrix plancticola. In Waldsee we also found mixotrophic ciliates Pelagothrix sp. (up 6 cells ml –1 ), Euplotes daidaleos (5 cells ml –1 ) and Coleps sp. (37 cells ml –1 ). The hymenostomatid Dexiotricha sp. (25 cells ml –1 ) dominated among the APP feeding ciliates. Loxodes sp. lived in the deepanoxy boundary. We observed sharp changes in ciliate biomass and composition changes along the boundary at a vertical distance interval of 0.3 m. 29
Page 1 and 2: ACADEMY OF SCIENCES OF THE CZECH RE
Page 3 and 4: CONTENTS THE INSTITUTE, SCIENTIFIC
Page 5 and 6: Academy of Sciences of the Czech Re
Page 7 and 8: RNDr. Dagmar Sirová (maternity lea
Page 9 and 10: 1 INTRODUCTION 1.1 Directors’ pre
Page 11 and 12: 2008-2012 Reg. code 206/08/0015, Ec
Page 13 and 14: EQUIPPMET Income Reserve for invest
Page 15 and 16: 2 JAROSLAV HRBÁČEK (1921-2010) He
Page 17 and 18: 3 RESERVOIRS 3.1 Regular monitoring
Page 19 and 20: 3.3 Regular monitoring: fish stock
Page 21 and 22: Fig. 1: A - Schematic drawing of wa
Page 23 and 24: in spring and summer periods, mainl
Page 25 and 26: 3.7 Deep spawning of perch Perca fl
Page 27: In late summer, a sudden flood even
Page 31 and 32: 5 SPECIAL INVESTIGATIONS 5.1 Effect
Page 33 and 34: found. The results from the field,
Page 35 and 36: pools in forest and alpine meadow s
Page 37 and 38: Fig. 10: Effect of various glucose
Page 39 and 40: 1942 Jezberová, J., Jezbera, J., B
Page 41 and 42: B: International Proceedings or Mon
Page 43 and 44: 1980 Potužák, J.*, Duras, J.*, Bo
Page 45 and 46: APPENDIX Jaroslav Hrbáček (1921-2
Page 47 and 48: Hrbáček, J., 1981: Possibilities
Page 49 and 50: Hrbáček, J., 2000: Vztah změn po
Page 51 and 52: Hrbáček, J., 1974: Vliv hnojení

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