limno Lab

Two symmetrical halves

Chlorophyta, Closterium

Chlorophyta, Pediastrum

Large, complex colonies containing 1000’s of cells.

Chlorophyta, Volvox

Each filament can be a few cm’s in length, forming mats. Distinctive spirally arranged chloroplasts

Chlorophyta, Spirogyra

Unicellular, flagellated

• Mostly freshwater (highly eutrophic habitats)

• Autotrophic & heterotrophic!

• cell wall made of protein

Euglenophyta, Euglena

Armour-plated with distinct groove that houses flagella

• These genera common in f.w.

Pyrrhophyta, Ceratium

Armour-plated with distinct groove that houses flagella

• These genera common in f.w.

Pyrrhophyta, Peridinium

Star shaped colony

Bacillariophyta, Asterionella

forms “raft” of cells (ribbon-like colonies)

Often present in spring blooms in f.w. lakes

Bacillariophyta, Fragilaria

Can form thick layers on stream beds choking out invertebrates

Major problem in N.Z.

Blooms even in nutrient poor conditions

No control methods available

Bacillariophyta, Didymosphenia

Division mostly marine but ~ 5% in f.w.

found in slow moving streams

Colonial alga with whorls of branches around a central axis

Not planktonic, but attached to substrate

Rhodophyta, Batrachospermum

Unicelluar with 2 flagella (unequal length)

Distinctive bean shape with unequal base

Lakes; planktonic

Cryptophyta, Cryptomonas

Division is uncommon in f.w.

Dinobryon common in oligotrophic and mesotrophic lakes in temperate regions, planktonic

Planktonic, can be unicellular or in branching colonies

Chrysophyta, Dinobryon

Filamentous, planktonic

Can produce neurotoxins = toxic if blooms

heterocysts are often obvious

Cyanophyta, Anabaena

Filamentous alga that appears to ‘oscillate’ or move

Common in ponds, lakes; planktonic and mat forming

Cyanophyta, Oscillatoria

Very small cells in a thick mucilaginous colony

Becomes amorphous as they break apart

Found in nutrient-rich waters and can produce dangerous toxins (microcystins)

Cyanophyta, Microcystis