Microbial symbionts associated with bryophytes of Arctic peatlands and their relevance for the carbon and nitrogen cycle

Microscopic image of bacteria associated with hyaline cells of an Arctic peat moss

Symbioses with the contribution of Prokaryotes, the bacteria and archaea, occur in various habitats including for example hot springs, cold streams, and the intestine. For about 40 years it has been known that bryophytes can live in symbiosis with Cyanobacteria carrying out nitrogen fixation. Only a few years ago, a symbiotic relation between methane oxidizing bacteria and peatland mosses was described. In particular, this association occurs with bryophytes such as Sphagnum and the so called brown mosses which are widely distributed in the pristine and often oligotrophic peatlands of the high northern latitudes. Most likely, methane oxidation bacteria thereby benefit from the release of oxygen as a result of photosynthesis through the moss. In turn, methane oxidizing bacteria utilize oxygen to consume methane; a process which results in the production of CO2 which again is available to the moss for assimilation.

The Helmholtz International Research Group ArcBiont investigates microbial communities associated with Arctic and Subarctic peat mosses from Svalbard, Finnmark, and the Siberian Lena Delta. As a reference, peatlands from northern Germany (TERENO NO sites) will be included. ArcBiont specifically focuses on microbial symbionts of the methane cycle and identifies their biogeography and relevance for the carbon cycle of Arctic peatlands. Based on molecular methods and enzyme activities, the project targets and characterizes functional genes such as pmoA, mcrA, and mmoX. Additionally, the project links the carbon with the nitrogen cycle by uncovering the importance of the microbial symbionts of the methane cycle for the process of nitrogen fixation. This likely is of relevance since many strains of methanotrophic bacteria and methanogenic archaea responsible for the oxidation and production of methane, respectively, are capable of nitrogen fixation. The importance of moss associated microbial communities for the element cycling of Arctic peatlands is of greater relevance given the present climatic changes the Arctic region is facing.

ArcBiont is a cooperation between the GFZ, Section 4.5 Geomicrobiology, and the University of Tromsø, Institute for Arctic and Marine Biology. The project started 1st of October, 2013, and will run for three years.

Dr. Susanne Liebner

Andrea Kiss (PhD student)


Prof. Mette Marianne Svenning, Alexander Tøsdal Tveit, UiT The Arctic University of Norway, Tromsø

Dr. Christian Knoblauch, Institute for Soil Science, University of Hamburg  

Prof. Hans-Wolfgang Hubberten, Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Potsdam



HGF - Helmholtz Association