Javascript is not activated in your browser. This website needs javascript activated to work properly.
You are here

The nitrogen fixation potential of arctic cryptogram species is influenced by enhanced UV-B radiation

  • Bjørn Solheim
  • Ulf Johanson
  • Terry V. Callaghan
  • John A. Lee
  • Dylan Gwynn-Jones
  • Lars Olof Björn
Publishing year: 2002
Language: English
Pages: 90-93
Publication/Series: Oecologia
Volume: 133
Issue: 1
Document type: Journal article
Publisher: Springer

Abstract english

Abstract. Effects of enhanced UV-B (representing a 15% ozone depletion) on cyanobacterial nitrogen fixation were measured at a high arctic site (Adventdalen, 79°N, Svalbard) and a subarctic site (Abisko, 68°N, Sweden). Nitrogen fixation potential (acetylene reduction) by cyanobacteria associated with the moss Sanionia uncinata in vegetation exposed to experimentally enhanced levels of UV-B for 3 and 4 years in the high arctic in Adventdalen was reduced by 50% compared to controls after 3 years. No reduction in nitrogen fixation potential was observed in cyanobacteria associated with the moss Hylocomium splendens when previously exposed to enhanced UV-B in Abisko for a 7-year period. However, in the same experiment a 50% increase in summer precipitation stimulated nitrogen fixation potential by up to 6-fold above the natural precipitation treatments both in cyanobacteria associated with vegetation exposed to natural and enhanced UV-B radiation. In contrast to the lack of UV effect on moss-associated nitrogen fixation at the subarctic site, nitrogen fixation potential by the dominant lichen species Peltigera aphthosa was reduced by 50% when measured after 8 years exposure to elevated UV-B treatment. Evidence from these studies highlights the importance of UV-B radiation for cyanobacterial nitrogen fixation in the Arctic and future impact on nitrogen availability in such plant communities.


  • Biological Sciences


  • Photobiology
  • Photobiology-lup-obsolete
  • ISSN: 1432-1939
Lars Olof Björn
E-mail: lars_olof [dot] bjorn [at] biol [dot] lu [dot] se

Professor emeritus

Molecular Cell Biology

+46 46 222 72 53