Impact of climate change on plant-microbe interactions in peatlands (CLIMABOG)

Peatlands are important long-term carbon (C) sinks, particularly Sphagnum-dominated peatlands (or bogs) where the bulk of living and dead biomass is formed by Sphagnum mosses. This peculiar genus of bryophytes is characterized by physiological and biochemical features that enhance the sequester of C by the production of litter extremely refractory to decomposition and by the presence of microbial inhibitors. Furthermore, Sphagnum productivity is strictly dependent on water surplus so that bogs are expected to be particularly sensitive to climate change. Indeed, any reduction of Sphagnum dominance in favor of vascular plants can jeopardize the C sink function of bogs because the litter of vascular plant is much more easily decomposable.

Some laboratory experiments suggest that increasing peat soil temperature can promote the growth of vascular plants at expense of mosses through an alteration of plant competitive ability for nutrient acquisition with respect to soil microbes. In the light of the ongoing climate change, a better understanding of the effects of climate warming on plant-microbe interactions in bogs is then crucial for predicting potential alteration on C sinking mediated by above- and belowground feedbacks.

The main aim of the research project CLIMABOG is to understand the relationships between plants and microbes for nutrient acquisition, in particular nitrogen (N) and phosphorus (P), and potential feedbacks on bog biogeochemistry along a gradient of increasing peat soil temperature. Increasing soil temperature will be obtained by selecting the study bogs along an altitudinal gradient so as to assess the effects of climate warming under conditions of long-term equilibrium between biogeochemistry, vegetation and local climatic conditions.

This project is funded by the Swiss National Science Foundation will run from spring 2010 through spring 2012.

• Luca Bragazza