Transcript Photoautotrophs

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
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