Do the Vegetation Feedbacks of Nitrogen Deposition Lead to Stronger or Weaker Carbon Sink in a Nutrient Limited Peatland Ecosystem?

Authors:
Tuula Larmola, Jill L. Bubier, Sari Juutinen, Elyn Humphreys, Tim R. Moore

Book:
Proceedings of the 14th International Peat Congress

Venue:
Stockholm

Keywords:
c-balance, co2, nitrogen, photosynthesis, respiration

Documentfile:
Larmola et al 2012: Do the Vegetation Feedbacks of Nitrogen Deposition Lead to Stronger or Weaker Carbon Sink in a Nutrient Limi

Summary:

Theme X. Peatland carbon budgets and greenhouse gas (GHG) fluxes

SUMMARY

We investigated vegetation and ecosystem CO₂ exchange at Mer Bleue Bog, Canada that has been fertilized with nitrogen, phosphorus and potassium or with nitrogen only for 7−12 years. Gross photosynthesis, ecosystem respiration and net CO₂ exchange were measured weekly during May−September 2011 using chambers and the seasonal CO₂ balance reconstructed using environmental time series. The highest nutrient additions were associated with 40% less net CO₂ uptake than in the control. A weaker C sink potential could be explained by changes in availability of nutrients limiting plant and microbial growth, a shift in biomass allocation to woody tissues, loss of Sphagnum moss and peat decomposability.