What was done
Recent (0-150 years) and long-term (2,000-10,000 years) apparent carbon (C) accumulation rates were derived for several ombrotrophic peatlands in eastern Canada with the help of ²¹⁰Pb- and ¹⁴C-dating of soil-core materials.

What was learned
The authors report that the average long-term apparent rate of C accumulation at 15 sites was 19±8 g C m^-2 yr^-1, which is comparable to long-term rates observed in Finnish bogs by Tolonen and Turunen (1996) and Turunen et al. (2002).  Recent C accumulation rates at 23 sites, on the other hand, were much higher, averaging 73±17 g C m^-2 yr^-1, which results, in the words of the authors, are also "similar to results from Finland (Tolonen and Turunen, 1996; Pitkanen et al., 1999) and for boreal Sphagnum dominated peat deposits in North America (Tolonen et al., 1988; Wieder et al., 1994; Turetsky et al., 2000)."

What it means
Calling recent rates of C accumulation "strikingly higher" than long-term rates, Turunen et al. suggest that increased nitrogen (N) deposition "leads to larger rates of C and N accumulation in the bogs, as has been found in European forests (Kauppi et al., 1992; Berg and Matzner, 1997), and could account for some of the missing C sink in the global C budget."  We also note that the warming experienced by the earth in recovering from the global chill of the Little Ice Age likely played a major role in enhancing peatland C accumulation rates (see, for example, Oechel et al. (2000), Camill et al. (2001), and Griffis and Rouse (2001)), and that the aerial fertilization effect provided by the increase in atmospheric CO2 concentration that began with the Industrial Revolution may have been a contributory factor too.

References
Berg, B. and Matzner, E.  1997.  Effect of N deposition on decomposition of plant litter and soil organic matter in forest systems.  Environmental Reviews 5: 1-25.

Camill, P., Lynch, J.A., Clark, J.S., Adams, J.B. and Jordan, B.  2001.  Changes in biomass, aboveground net primary production, and peat accumulation following permafrost thaw in the boreal peatlands of Manitoba, Canada.  Ecosystems 4: 461-478.

Griffis, T.J. and Rouse, W.R.  2001.  Modelling the interannual variability of net ecosystem CO2 exchange at a subarctic sedge fen.  Global Change Biology 7: 511-530.

Kauppi, P.E., Mielikainen, K. and Kuusela, K.  1992.  Biomass and carbon budget of European forests.  Science 256: 70-74.

Oechel, W.C., Vourlitis, G.L., Hastings, S.J., Zulueta, R.C., Hinzman, L. and Kane, D.  2000.  Acclimation of ecosystem CO2 exchange in the Alaskan Arctic in response to decadal climate warming.  Nature 406: 978-981.

Pitkanen, A., Turunen, J. and Tolonen, K.  1999.  The role of fire in the carbon dynamics of a mire, Eastern Finland.  The Holocene 9: 453-462.

Tolonen, K., Davis, R.B. and Widoff, L.  1988.  Peat accumulation rates in selected Maine peat deposits.  Maine Geological Survey, Department of Conservation Bulletin 33: 1-99.

Tolonen, K. and Turunen, J.  1996.  Accumulation rates of carbon in mires in Finland and implications for climate change.  The Holocene 6: 171-178.

Turetsky, M.R., Wieder, R.K., Williams, C.J. and Vitt, D.H.  2000.  Organic matter accumulation, peat chemistry, and permafrost melting in peatlands of boreal Alberta.  Ecoscience 7: 379-392.

Turunen, J., Tomppo, E., Tolonen, K. and Reinikainen, A.  2002.  Estimating carbon accumulation rates of undrained mires in Finland: Application to boreal and subarctic regions.  The Holocene 12: 69-80.

Wieder, R.K., Novak, M., Schell, W.R. and Rhodes, T.  1994.  Rates of peat accumulation over the past 200 years in five Sphagnum-dominated peatlands in the United States.  Journal of Paleolimnology 12: 35-47.