Cyanobacteria (blue green algae)
Planktothrix is a filamentous cyanobacterium that can form rather long filaments relative to its width. Planktothrix has no sheath, no akinetes, and no heterocysts. Planktothrix has some gas vacuoles but not as much as Microcystis, which results in the mix of blue-green and black colors of the filaments. Planktothrix reaches high biomasses in Sandusky Bay and in rivers. Planktothrix produces microcystins.