Blood snow

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Red snow algae above the Simplon Pass at 2130  m above sea level. M. (2019)
Blood snow

Blood snow or red snow is a natural phenomenon in which old snow from winter can turn pink to carmine red due to microorganisms ( snow algae ) during the melting period. This mainly happens in high mountains and polar regions during the summer months. Without knowing the causer of biological origin, blood snow was already described by Aristotle and the Vikings.

The culprits are snow-dwelling green algae, which are referred to as psychrophiles due to their physiological adaptation to cold and frost and are also included in the cryoflora . These snow algae are unicellular organisms with an orange, pink to dark red color in the cytoplasm. Most of the representatives are traditionally placed in the genera Chlamydomonas and Chloromonas , which belong to the green algae . The normally typical green coloration of the cells of this group of algae caused by chlorophylls is covered in the representatives of the red snow by secondary carotenoids , primarily astaxanthin . An outdated name for this pigment is hematochrome .

The red snow algae protect themselves with the help of astaxanthin from the strong light and UV radiation that occurs especially at extreme altitudes and in polar regions . Chlamydomonas nivalis is the longest known species of this blood-snow-causing genus and has been described by many mountain and polar regions of the world. Today, however, it must be viewed as a collective species for a still unknown number of morphologically very similar algae species that live in snow.

Analogous to the blood rain (the Sahel wind), red dust from deserts carried by winds can also lead to blood snow, whereby the snowflakes absorb the sand in the fall and have a (yellowish / brownish) red color as precipitation .

See also

Web links

Commons : Blutschnee  - Collection of images, videos and audio files
Wiktionary: Blutschnee  - explanations of meanings, word origins, synonyms, translations

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  1. ↑ Petra Werner: Roter Schnee: or The search for the coloring principle. Oldenbourg Akademieverlag, 2007, ISBN 978-3-05-004432-3 .
  2. ↑ Franz-Christian Czygan : Blood rain and blood snow: Nitrogen deficiency cells from Haematococcus pluvialis and Chlamydomonas nivalis. In: Archives of Microbiology. Volume 74, Number 1, March 1970.
  3. ↑ Holly L. Gorton, Thomas C. Vogelmann: Ultraviolet Radiation and the Snow Alga Chlamydomonas nivalis (Bauer) Wille. In: Photochemistry and Photobiology. Vol. 77 (2003), No. 6, pp. 608-615.
  4. ↑ Erzsébet Kol: Cryobiology: Biology and Limnology of Snow and Ice I, Kryovegetation (= The inland waters. Individual representations from limnology and its neighboring areas. Volume. 24). E. Schweizerbart'sche Verlagbuchhandlung (Nägele and Obermiller), Stuttgart 1968, DNB 457255153 .