Järviwiki:Ohje/Näin teet havainnon/Sinilevätilanne/en

Assessing the blue-green algae situation is one of the easiest observations anyone can make. Blue-green algae detection is done visually and does not require tools. The observation "No cyanobacteria" is also important and worth reporting.

Selection of observation site

To observe the blue-green algae situation, choose a place with good visibility in the water area and where the water can change freely.

Identification of cyanobacteria

Minor cyanobacteria appear in the water as small yellowish or greenish pollen-like peaks. In calm weather cyanobacteria form a gauze-like greenish film on the surface of the water.

Pollen seems misleadingly similar to cyanobacteria. However, pollen is especially present in water in spring and early summer, but cyanobacteria usually only become abundant after mid-summer when the waters warm up. If there is a lot of pollen in the water, it is usually also abundant on the beach.

The glass test and the stick test are good tools for identifying cyanobacteria.

The glass test

Take algae water in a glass or glass jar and let it stand for about an hour without moving. If green particles rise to the surface, it is blue-green algae.

The stick test

Test with a stick to see if the algae mass is solid and can be lifted. If the algae remains hanging on a stick, it is a harmless filamentous algae. Blue-green algae, on the other hand, decomposes on contact into particles in water.

Estimation of cyanobacterial abundance

Leväesiintymän runsautta arvioidaan silmämääräisesti neliportaisella asteikolla.

Ei sinilevää	Veden pinnalla tai rantaveden rajassa ei ole havaittavissa sinilevää. Näkösyvyys on normaali.
Hieman sinilevää	Sinilevää on havaittavissa vihertävinä hiutaleina tai tikkusina vedessä. Levää näkyy, jos vettä ottaa läpinäkyvään astiaan. Rannalle on saattanut ajautua kapeita leväraitoja. Levä heikentää näkösyvyyttä.
Runsaasti sinilevää	Vesi on selvästi leväpitoista tai veden pinnalle on kohonnut pieniä levälauttoja tai rannalle on ajautunut leväkasaumia.
Erittäin runsaasti sinilevää	Levä muodostaa laajoja levälauttoja tai sitä on ajautunut rannalle paksuiksi kasaumiksi.

Hieman sinilevää

Runsaasti sinilevää

Erittäin runsaasti sinilevää