Distribution in scandinavian waters
Maximum length: About 1 mm.
Appearance: These microscopic bacterias have several closely
related specie, where some can appear in such vast quantities that they
build a dark coloured coating on the rocks and cliffs. This coating
can be very slippery when wet. Even if the coatings are nearly black,
under magnification the cells
are green to blue-green in colour.
Compare with salt
Depth: The belts
are found from sea level and about 10 m up on the cliffs.
Environment: Cyranobacteria is found on cliffs
and rocks that preferably face the southwest. The largest areas
these bacterias cover are where powerful
waves and surf reach the beach.
Misc.: When a slippery, black membrane is scraped from the rocks,
cell threads from many specie are present. It can be composed of different
species of the calothrix family, but can also contain certain
red and green algae. But it is usually some form of calothrix specie
that dominate the black belts above the waterline.
Classification: Has its own group known as