What are Cyanobacteria?
Cyanobacteria, commonly called "blue-green algae", are among the oldest life forms on Earth. They have fundamentally changed our planet β and can become dangerous under certain conditions.
π¬Not True Algae
The name "blue-green algae" is scientifically incorrect. Cyanobacteria are not algae but bacteria β specifically prokaryotes, cells without a true nucleus.
β True Algae (Eukaryotes)
- β’ Have a cell nucleus
- β’ More complex cell structure
- β’ Belong to plants/protists
β Cyanobacteria (Prokaryotes)
- β’ No true cell nucleus
- β’ Simpler cell structure
- β’ Are true bacteria
The name "blue-green algae" dates from the 19th century when they couldn't be properly classified. The scientifically correct name is Cyanobacteria (from Greek "kyanos" = blue).
βοΈThe Inventors of Photosynthesis
About 2.4 billion years ago, cyanobacteria triggered the so-called "Great Oxygenation Event" β they enriched Earth's atmosphere with oxygen for the first time.
Without cyanobacteria, there would be no life as we know it. They produced the oxygen that enabled the emergence of complex life forms. Today, marine cyanobacteria still produce about 20-30% of global oxygen.
Evolutionary Timeline
πWhy Do They Bloom?
Under certain conditions, cyanobacteria can multiply explosively β this is called an "algal bloom".
Optimal Conditions for Blooms:
β οΈ Climate Change Amplifies the Problem
Studies show that the frequency and intensity of cyanobacterial blooms is increasing worldwide. Higher temperatures and changing precipitation patterns create ideal conditions for mass proliferation.
πHow to Recognize Cyanobacteria?
Typical Recognition Signs:
Characteristic blue-green to turquoise color, but can also be green, brown or reddish
In heavier infestations, oily-looking streaks or mats form on the water surface
In severe blooms, water becomes thick and opaque β like green pea soup
Decomposing cyanobacteria often cause an unpleasant, earthy smell
β οΈ Important: Don't touch, don't drink!
If you see a possible cyanobacteria bloom, avoid contact. Even if the water looks clear, toxins may be present.
β οΈWhy Are They Dangerous?
Not all cyanobacteria are dangerous. But about 40 genera can produce toxins (cyanotoxins) that pose serious health risks.
The Main Toxin Groups:
Microcystins
Hepatotoxin
Damages the liver, can promote liver cancer
Cylindrospermopsin
Cytotoxin
Damages liver, kidneys and other organs
Anatoxins
Neurotoxin
Affects nervous system, can cause respiratory paralysis
Saxitoxins
Neurotoxin
Blocks nerve impulses, extremely dangerous
πSummary
- βCyanobacteria are bacteria, not algae β despite the name "blue-green algae"
- βThey are 3.5 billion years old and enriched Earth's atmosphere with oxygen
- βUnder certain conditions (warmth, nutrients, calm water) they form mass blooms
- βAbout 40 genera can produce dangerous toxins
- βClimate change is amplifying the problem worldwide