Quantifying nitrogen-fixation in feather moss carpets of boreal forests

Nature. 2002 Oct 31;419(6910):917-20. doi: 10.1038/nature01051.


Biological nitrogen (N) fixation is the primary source of N within natural ecosystems, yet the origin of boreal forest N has remained elusive. The boreal forests of Eurasia and North America lack any significant, widespread symbiotic N-fixing plants. With the exception of scattered stands of alder in early primary successional forests, N-fixation in boreal forests is considered to be extremely limited. Nitrogen-fixation in northern European boreal forests has been estimated at only 0.5 kg N ha(-1) yr(-1); however, organic N is accumulated in these ecosystems at a rate of 3 kg N ha(-1) yr(-1) (ref. 8). Our limited understanding of the origin of boreal N is unacceptable given the extent of the boreal forest region, but predictable given our imperfect knowledge of N-fixation. Herein we report on a N-fixing symbiosis between a cyanobacterium (Nostoc sp.) and the ubiquitous feather moss, Pleurozium schreberi (Bird) Mitt. that alone fixes between 1.5 and 2.0 kg N ha(-1) yr(-1) in mid- to late-successional forests of northern Scandinavia and Finland. Previous efforts have probably underestimated N-fixation potential in boreal forests.

MeSH terms

  • Acetylene / metabolism
  • Bryopsida / metabolism*
  • Bryopsida / microbiology*
  • Cyanobacteria / metabolism*
  • Finland
  • Kinetics
  • Nitrogen Fixation*
  • Norway
  • Plant Leaves / metabolism
  • Plant Leaves / microbiology
  • Sweden
  • Symbiosis*
  • Trees*


  • Acetylene