Presentation on theme: "PHYTOPLANKTON DYNAMICS IN LAKE CHALLA AS DERIVED"— Presentation transcript:
1 PHYTOPLANKTON DYNAMICS IN LAKE CHALLA AS DERIVED FROM SEDIMENT TRAP ANALYSESChristine CocquytNational Botanic Garden of BelgiumLimnology Unit, Ghent UniversityPrésentation: YvesNational Botanic Garden of Belgium
2 Quantitative phytoplankton analyses Uthermöhl method:- “sedimentation chamber” of 10 ml- inverted microscope- counts of organisms and colonies (known surface area)Calculation- number of cells/ml- conversion to biovolumes
3 Major algal groups - percentages derived from biovolumes Lake Challa2007200820102011Présentation: YvesMajor algal groups - percentages derived from biovolumes
22 National Botanic Garden of Belgium Conclusions- phytoplankton dominated by a Diatom-Chlorophytes communityseasonal and interannual variability in major algal groupsinterannual variability in diatom composition, e.g. Synedra/Ulnaria spp. and “long” Nitzschia spp.“small” Nitzschia not important in the actual phytoplankton, probably benthic specieswater samples more reliable than filtered samplesnon-diatoms probably underestimated – disintegration during sedimentation- need of actual phytoplankton samples (taken during the monthly sampling of the sediment trap)Présentation: YvesNational Botanic Garden of Belgium
23 National Botanic Garden of Belgium AcknowledgementDirk Verschurenall persons involved in the sampling of the sediment trap and in the proceeding of the samplesPrésentation: YvesNational Botanic Garden of Belgium
24 Thank you for your attention Présentation: YvesNational Botanic Garden of Belgium
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