Pseudanabaena

Pseudanabaena spp. · Phytoplankton

Under the microscope · Photo: CC0

NativePlanktonic cyanobacteria (in the water)May produce toxins

May produce toxins

Only a lab test shows whether a bloom is toxic. Keep people, pets and livestock out of discolored or scummy water until it is tested.

How to identify Pseudanabaena

Under the microscope: short, thin filaments of a few cylinder shaped cells with clear pinches between each cell
No heterocysts and no sheath; often found inside or on Microcystis colonies
Pale blue green color
In the water: not visible on its own; rides along with other blooms

Similar species

Limnothrix and Planktothrix filaments are longer with less obvious pinches between cells; young Dolichospermum filaments have rounder cells.

Profile

Season	Summer and early fall.
Starts	About 60 F and up
Light	Tolerates low light
Depth	Throughout the water column
How it spreads or reproduces	Filament breakage
Habitat	Eutrophic ponds, lakes and reservoirs, often growing with Microcystis blooms.

Why it matters in a lake

A small blue green that is very common in bloom samples. Microcystin and some taste and odor compounds such as MIB have been reported from some strains.