The water look greenish. Is it cyanobacteria?
The water look greenish. Is it cyanobacteria?
Often it is, but: the greenish shade of water is not always due to cyanobacteria or other algae.
The reason for the greenish color of the water can be, for example, one of the following:
turbid water deposited in water layers below the surface,
visibility of benthic vegetation through water in shallow areas,
pollen in the water,
snow or ice mixed with water,
decomposition products of dead algae mixed with water,
cyanobacteria or other algae in water.
Without expertise, it may be difficult to interpret the causes for the greenish hue of the water. At the bottom of the page there are examples of cases where the water appears to turn green due to various reasons.
Please also note that it is not possible to make algal species determinations based on the data in the Tarkka service. Depending on the season, several species of algae occur in Finnish waters. More detailed information on the observed algae species can be found on Syke’s algae status pages and waterinfo.fi
Examples
Resuspension on the west coast
Resuspension is a phenomenon in which strong winds mix bottom material with the entire water layer in a shallow coastal area. This can be seen as several greenish-brown ‘zones’ along the coast. Resuspension is quite common on the west coast and especially in the Oulu region in the Bothnian Bay.