Freshwater plankton  Free living in open water  Position mostly determined by currents (as opposed to i.e. fish)  Three main groups – NOT exact!! 1.Bacterioplankton 2.Phytoplankton 3.Zooplankton

Bacteria and Protists Bacteria Cyanobacteria (Blue-green algae) – photosynthesis - i.e. Aphanizomenon flos- aquae, Anabaena Heterotrophic – use organic molecules for nutrition – i.e. Azotobacter, Clostridium Nitrogen fixation in both groups Protists – unicellular, not animals, plants, bacteria, or fungi Ciliates – i.e. Paramecium Flagellates – i.e. Euglena, Dinoflagellates Anabaena

Phytoplankton Phytoplankton – “Algae” – plants and others with photosynthesis Phytoplankton – “Algae” – plants and others with photosynthesis Green algae – i.e. Volvox, Spirogyra, Chlorella, Desmids Green algae – i.e. Volvox, Spirogyra, Chlorella, Desmids Diatoms – silica cell walls, yellow- brown chloroplasts Diatoms – silica cell walls, yellow- brown chloroplasts Pediastrum Asterionella Spirogyra

Zooplankton Three Main Groups 1.Cladocera 2.Copepoda (Crustaceans) 3.Rotifera Daphnia pulex

Cladocera - Cladocera - perloočky Filtration feeding Filtration feeding Parthogenesis Parthogenesis Asexual reproduction of females Asexual reproduction of females Poor conditions – males appear, sexual reproduction producing ephippia (winter eggs) Poor conditions – males appear, sexual reproduction producing ephippia (winter eggs) Ceriodaphnia reticulata Bosmina longirostris

Copepoda - Copepoda - klanonožci Filtrators and Predators Filtrators and Predators Cyclopoida – i.e. Cyclops Cyclopoida – i.e. Cyclops Calanoida – i.e. Diaptomus Calanoida – i.e. Diaptomus Harpacticoida Harpacticoida Nauplius Nauplius Larval stages (usually 6) Larval stages (usually 6)

Rotatoria - Rotatoria - vířníci Corona – cilia for movement, capturing food Corona – cilia for movement, capturing food Mastax – grinding organ made of chitin Mastax – grinding organ made of chitin Carapace present in most species Carapace present in most species Asplanchna Keratella

Chaoborus  Diptera  Important predator on plankton and other insects

Web links Then “Micro-organisms in ponds” eries/moviegallery/pondscum.html eries/moviegallery/pondscum.html eries/moviegallery/pondscum.html eries/moviegallery/pondscum.html /index.html /index.html /index.html /index.html – i.e. search for “plankton” – i.e. search for “plankton”