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Dieren en planten

Crustaceans   Water fleas   Zebra mussel   Micro-organisms   Bacteria   Cyanobacteria   Freshwater bivalves   

Water en land

  • Dut: Cyanobacterie, blauwwier, blauwalg
  • Lat: Microcystis aeruginosa, Aphanizomenon, Oscillatoria, Coelosphaerium
  • Eng: Cyanobacteria, blue-green algae
  • Ger: Blaualgen, Cyanobakterien
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Blue-green algae, NIOZ (www.nioz.nl)

Cyanobacteria

Cyanobacteria are the oldest forms of life on earth. They are bacteria containing leaf green, which means they can obtain energy from photosynthesis. Cyanobacteria are also called blue-green algae. Fossil specimen from this group have been found dating back more than three billion years. Cyanobacteria in the sea plays a more minor role than other marine plankton. Some species on the mudflats make use of solar energy while others can survive where there is no oxygen or light by degrading chemical compounds. An important function of the land-living cyanobacteria in the ecosystem is its capacity for fixing nitrogen. Plants such as clover and sea buckthorn add nitrogen to the soil from the air by working together with cyanobacteria. Lichens are an intimate relationship between fungi and an alga or a cyanobacteria. That is why thy are able to survive on very dry or nutrient-poor places.

  • Blossoming of cyanobacteria in fresh surface water

    When the weather is warm and there are lots of nutrients in fresh water, cyanobacteria can multiply very rapidly. Thick floating layers can form, making one think that someone threw blue-green paint into the water. The cyanobacteria releases toxic materials which can be hazardous for man and animal. Animals that consume the cyanobacteria, such as water fleas and zebra mussels, accumulate the poisonous material. Fish and birds that consume the algae-feeding animals can die from the poisoning. For people that swim in such contaminated water, it can cause dizziness, nausea, headaches, stomach cramps, skin irritations and earaches. Children, elderly and people in poor health are particularly susceptible.
    In the winter, the blue-green algae clot together and sink to the bottom, where they 'hibernate'. IT is then easy to remove them by dredging the bottom.