Title: The dependence of photosynthesis and respiration rates on environmental factors in different microsites from a boreal oligotrophic pine fen

Author: Anu Kettunen

Status: Proceedings of The spirits of peatlands, IPS, Jyväskylä, September 7-9, 1998, pp. 234-236.


Carbon balance in mires depends on the rates of photosynthesis and respiration which are both affected by environmental factors. We used earlier data (Alm et al. 1997) on the net CO2 exchange (Pn), the total dark respiration (Rtot), photosynthetically active radiation (PAR), temperature (T) and water table (WT) series measured from a Finnish low-sedge Sphagnum papillosum pine fen to analyze the dependence of photosynthesis and respiration rates on environmental variables. The net CO2 exchange and respiration were measured using chamber technique in 18 study plots during the summer season 1993. Based on vegetation and water tables, the study plots were classified to 4 microsite types: hummocks, Carex lawns, Eriophorum lawns and flarks (minerotrophic hollows). The relationships between photosynthesis and respiration rates on the environmental variables were studied separately for each microsite class. Photosynthesis rates in the microsites depended on photosynthetically active radiation corrected by the effective temperature sum index. Respiration rates were exponentially related to temperatures and water tables in the microsites. Using the estimated relationships, the daily and annual carbon balances in each microsite class were calculated for the summer period.


J. Alm, A. Talanov, S. Saarnio, J. Silvola, E. Ikkonen, H. Aaltonen, H. Nykänen and Pertti J. Martikainen (1997). Reconstruction of the carbon balance for microsites in a boreal oligotrophic pine fen, Finland, Oekologia, 110, 423-431.