Reconstruction of the carbon balance for microsites in a boreal oligotrophic pine fen, Finland

Abstract

Carbon dioxide (CO) exchange was studied at flark (minerotrophic hollow), lawn and hummock microsites in an oligotrophic boreal pine fen. Statistical response functions were constructed for the microsites in order to reconstruct the annual CO exchange balance from climate data. Carbon accumulation was estimated from the annual net CO exchange, methane (CH) emissions and leaching of carbon. Due to high water tables in the year 1993, the average carbon accumulation at the flark, Eriophorum lawn, Carex lawn and hummock microsites was high, 2.91, 6.08, 2.83 and 2.66 mol C m, respectively, and for the whole peatland it was 5.66 mol m year. During the maximum primary production period in midsummer, hummocks with low water tables emitted less methane than predicted from the average net ecosystem exchange (NEE), while the Carex lawns emitted slightly more. CH release during that period corresponded to 16% of the contemporary NEE. Annual C accumulation rate did not correlate with annual CH release in the microsites studied, but the total community CO release seemed to be related to CH emissions in the wet microsites, again excluding the hummocks. The dependence of CO exchange dynamics on weather events suggests that daily balances in C accumulation are labile and can change from net carbon uptake to net release, primarily in high hummocks on fens under warmer, drier climatic conditions.

The Impact of Experimental Temperature and Water Level Manipulation on Carbon Dioxide Release in a Poor Fen in Northern Poland

“…through photosynthesis) and carbon release from the peat soil (Alm et al 1997). Increase global warming, such as the increased temperature and resulting water table drawdown, may imbalance peatland carbon cycles, resulting in a large feedback to the global climate.…”

Do we miss the hot spots? – The use of very high resolution aerial photographs to quantify carbon fluxes in peatlands

“…Riutta et al (2007), along transects e.g. Alm et al (1997) and Laine et al (2006), or with a landcover map of the complete area under study e.g. Bubier et al (2005).…”

Scots pine litter decomposition along drainage succession and soil nutrient gradients in peatland forests, and the effects of inter-annual weather variation

“…The soil C sink of a peatland (mire) is labile, and its persistence is sensitive to weather variations, especially moisture conditions. Large soil C losses from pristine mires have resulted following extended summer droughts (Alm et al, 1997(Alm et al, , 1999Moore et al, 2002). These results have raised a postulate that long-term water-level drawdown will diminish or end the C sink function of a peatland.…”