Prokaryotes Bacteria and Archea No membrane bound organelles

Prokaryotes – Bacteria and Archea No membrane bound organelles Asexual reproduction by binary fusion Large surface area to volume ratio Single celled or colonial

Ecology Photoautotrophs – i. e. cyanobacteria (blue-green algae) Chemoheterotrophs and Photohetertrophs – using active transport, more efficient at low nutrient concentrations Anaerobic metabolism – what’s going on in the hypolimnion of a stratified, anoxic lake? Diapause – it may be that the dormancy is very important in bacteria

Cyanobacteria Prokaryotes (no nucleus or organelles) Blue-green Pigment = Chl a

Filamentous blue-green algae (Cyanophyta)

Protista – Protozoa and algae Eukaryotic (membrane bound organelles, nucleus, mitochondria, chloroplasts in photosynthetic protists) Single celled (although may be colonial)

Protozoa Heterotrophic Protists Paramecium, amoebas, Euglena, Hydra Also Giardia and Cryptosporidium

Photoautotrophic Protista – Algae Phytoplankton Single celled or colonial Floating Benthic algae Attached to surfaces (rocks, sediment)

Chlorophyta - Green-yellow green Pigment = Chl a and b Some have flagella

Chrysophyta Yellow green to golden brown Pigment = Chl a and c Some have 2 flagella

Chrysophyta (Golden-brown algae) Diatoms Brown to light green Pigment = Chl a and c Some have flagella Silica walls – composed of 2 frustules

Euglenophyta Pigment = Chl a and b All have flagella Eyespots Most are heterotrophic and autotrophic

Dinoflagellata Gray Pigment = Chl a and c Two flagella Some are highly toxic

Pfisteria

Reproduction - diverse Sexual reproduction – possibly motile gametes or conjugation tubes Asexual reproduction Encystment usually binary fission Germination Vegetative cell resistant cell (resting stage)

Fungi Chemoautotrophs (saprobic) Yeasts Hyphae grouped into mycellium Sexual and asexual reproduction

Ecological importance Breakdown of detritous Parasites on other aquatic organisms

Periphyton (or aufwuchs) – pond scum

A community of algae, fungi, bacteria