Presentation is loading. Please wait.

Presentation is loading. Please wait.

PHYTOPLANKTON DYNAMICS IN LAKE CHALLA AS DERIVED FROM SEDIMENT TRAP ANALYSES Christine Cocquyt National Botanic Garden of Belgium Limnology Unit, Ghent.

Similar presentations


Presentation on theme: "PHYTOPLANKTON DYNAMICS IN LAKE CHALLA AS DERIVED FROM SEDIMENT TRAP ANALYSES Christine Cocquyt National Botanic Garden of Belgium Limnology Unit, Ghent."— Presentation transcript:

1 PHYTOPLANKTON DYNAMICS IN LAKE CHALLA AS DERIVED FROM SEDIMENT TRAP ANALYSES Christine Cocquyt National Botanic Garden of Belgium Limnology Unit, Ghent University National Botanic Garden of Belgium

2 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 Challa

4 Gomphocymbella Synedra/Ulnaria Nitzschia “long” percentages derived from biovolumes

5 Encyonema/ Cymbella spp. Staurosira/ Staurosirella spp. Rhopalodia spp percentages derived from biovolumes

6 Cosmarium spp. Closteriopsis acicularis Oocystis sp percentages derived from biovolumes

7 Filtered versus water sample

8 Challa phytoplankton productivity flux (cell volume/day cm2) filtered samplewater sample

9 filtered samples water samples

10 Lake Challa – July 2010 – filtered sample

11 Lake Challa – January 2011 – water sample

12 12 Species diversity

13 Diatoms 44 Chlorophyta 40 Cyanobacteria 15 Euglenophyta 2 Dinophyta 2 Chrysophyta 3 Total106

14 Achnanthidum exiguum Achnanthidum sp. Amphora copulata Amphora pediculus Cymatopleura clavata Cymbella sp. Diploneis sp. Encyonema meulleri Encyonema minutum Gomphocymbella sp. Gomphonema affine Gomphonema parvulum Gomphonema sp. Hantzschia amphioxys Navicula sp. 1 Navicula sp. 2 Navicula sp. 3 Navicula sp. 4 Nitzschia bacata Nitzschoa epiphyticoides Nitzschia fonticola Nitzschia lancettula Nitzschia palea Nitzschia palea var. tropica Nitzschia vanoyei Nitzschia sp. 1 Nitzschia sp. 2 Nitzschia sp. 3 Nitzschia sp. 4 Placoneis gastrum Rhopalodia gibba Rhopalodia gibberula Rhopalodia gracilis Rhopalodia hirudiniformis Sellaphora nyassensis Sellaphora pupula Stauroneis sp. Staurosira construens Staurosirella pinnata Surirella sp. Ulnaria acus Ulnaria danica Ulnaria ulna Urosolenia sp. Bacillariophyta

15 Chlorophyta Ankistrodesmus sp. Chlorococcus sp. Chlorella sp. Closteriopsis acicularis Closteriopsis acicularis var. africana Crucigeniella quadrata Crucigeniella sp. Dictyosphaerium pulchellum Dictyosphaerium tetrachotomum Didymosphenia sp. Eremosphaeria sp. Kirchneriella arcuata Kirchneriella contorta var. elongata Kirchneriella microscopica Kirchneriella obesa cf. Kirchneriella sp. Lagerheimia chodatii Lagerheimia ciliata Lagerheimia citriformis Lagerheimia subsalsa Lobocystis planctonica Monoraphidium arcuatum Monoraphidium irregulare Monoraphidium mirabile Monoraphidium minutum Oocystis sp. Oonephris sp. cf. Oonephris sp. Podohedra falcata Schroederia planctonica Tetraedron triangulare Tetraedron minimum Treubaria setigera Tetrastrum komareckii sp. 1 sp. 2 sp. 3 Cosmarium sp. 1 Cosmarium sp. 2 Staurastrum

16 Cyanobacteria Chroococcus limneticus Chroococcus dispersus Chroococcus sp. Chroococalles sp. cf. Aphanocapsa microscopica cf. Gloeotrichia sp. Gomphosphaeria cf. natans Synechococcus elongatus Planktolyngbya sp. Microcrocis sp. Microcystis sp. Snowella sp. sp. 1 sp. 2 sp. 3

17 Euglenophyta Trachelomonas volvocina Trachelomonas volvocinopsis Dinophyta Peridinium sp. Gymnodinium sp. Chryso/Cryptophyta Chrysomonas sp. cf. Chrysomonas sp. sp.

18 Bacillariophyta - Diatoms Staurosira construens Gomphocymbella Rhopalodia gibba Encyonema minutum Sellaphora nyassensis Nitzschia “small” Nitzschia “long” Gomphonema Diploneis

19 Chlorophyta – green algae Oocystis Tetraedron minimum Cosmarium Closteriopsis acicularis Treubaria setigera Staurodesmus Tetrastrum cf. Eremosphaera Kirchneriella sp. Lagerheimia

20 Chlorophyta – green algae Oocystis Tetraedron minimum Cosmarium Closteriopsis acicularis Treubaria setigera Staurodesmus Tetrastrum cf. Eremosphaera Kirchneriella sp. Lagerheimia

21 Trachelomonas Euglenophyta Peridinium cf. africanum Dinophyta

22 Conclusions National Botanic Garden of Belgium - phytoplankton dominated by a Diatom-Chlorophytes community - seasonal and interannual variability in major algal groups -interannual variability in diatom composition, e.g. Synedra/Ulnaria spp. and “long” Nitzschia spp. -“small” Nitzschia not important in the actual phytoplankton, probably benthic species -water samples more reliable than filtered samples -non-diatoms probably underestimated – disintegration during sedimentation - need of actual phytoplankton samples (taken during the monthly sampling of the sediment trap)

23 Acknowledgement National Botanic Garden of Belgium Dirk Verschuren all persons involved in the sampling of the sediment trap and in the proceeding of the samples

24 Thank you for your attention National Botanic Garden of Belgium


Download ppt "PHYTOPLANKTON DYNAMICS IN LAKE CHALLA AS DERIVED FROM SEDIMENT TRAP ANALYSES Christine Cocquyt National Botanic Garden of Belgium Limnology Unit, Ghent."

Similar presentations


Ads by Google