References

Biogeosciences

1726-4189

Copernicus Publications

Göttingen, Germany

10.5194/bg-9-4071-2012

Northern peatland carbon stocks and dynamics: a review

Z. C.

Department of Earth and Environmental Sciences, Lehigh University, 1 West Packer Avenue, Bethlehem, PA 18015, USA

22 10 2012

9 10 4071 4085

2012

This work is licensed under the Creative Commons Attribution 3.0 Unported License. To view a copy of this licence, visit https://creativecommons.org/licenses/by/3.0/

This article is available from https://bg.copernicus.org/articles/9/4071/2012/bg-9-4071-2012.html

The full text article is available as a PDF file from https://bg.copernicus.org/articles/9/4071/2012/bg-9-4071-2012.pdf

Peatlands contain a large belowground carbon (C) stock in the biosphere, and their dynamics have important implications for the global carbon cycle. However, there are still large uncertainties in C stock estimates and poor understanding of C dynamics across timescales. Here I review different approaches and associated uncertainties of C stock estimates in the literature, and on the basis of the literature review my best estimate of C stocks and uncertainty is 500 ± 100 (approximate range) gigatons of C (Gt C) in northern peatlands. The greatest source of uncertainty for all the approaches is the lack or insufficient representation of data, including depth, bulk density and carbon accumulation data, especially from the world's large peatlands. Several ways to improve estimates of peat carbon stocks are also discussed in this paper, including the estimates of C stocks by regions and further utilizations of widely available basal peat ages. Changes in peatland carbon stocks over time, estimated using Sphagnum (peat moss) spore data and down-core peat accumulation records, show different patterns during the Holocene, and I argue that spore-based approach underestimates the abundance of peatlands in their early histories. Considering long-term peat decomposition using peat accumulation data allows estimates of net carbon sequestration rates by peatlands, or net (ecosystem) carbon balance (NECB), which indicates more than half of peat carbon (> 270 Gt C) was sequestrated before 7000 yr ago during the Holocene. Contemporary carbon flux studies at 5 peatland sites show much larger NECB during the last decade (32 ± 7.8 (S.E.) g C m−2 yr–1) than during the last 7000 yr (&sim; 11 g C m−2 yr–1), as modeled from peat records across northern peatlands. This discrepancy highlights the urgent need for carbon accumulation data and process understanding, especially at decadal and centennial timescales, that would bridge current knowledge gaps and facilitate comparisons of NECB across all timescales.

References 1

Adams, J. M. and Faure, H.: A new estimate of changing carbon storage on land since the last glacial maximum, based on global land ecosystem reconstruction, Global Planet. Change, 16/17, 3–24, 1998.

Alm, J., Schulman, L., Walden, J., Nykänen, H., Martikainen, P. J., and Silvola, J.: Carbon balance of a boreal bog during a year with an exceptionally dry summer, Ecology, 80, 161–174, 1999.

Armentano, T. V. and Menges, E. S.: Patterns of change in the carbon balance of organic soil-wetlands of the temperate zone, J. Ecol., 74, 755–774, 1986.

Aurela, M., Laurila, T., and Tuovinen, J. P.: The timing of snow melt controls the annual CO2 balance in a subarctic fen, Geophys. Res. Lett., 31, L16119, <a href="http://dx.doi.org/10.1029/2004GL020315">https://doi.org/10.1029/2004GL020315</a>, 2004.

Baird, A. J., Belyea, L. R., and Morris, P. J.: Upscaling of peatland-atmosphere fluxes of methane: Small-scale heterogeneity in process rates and the pitfalls of "bucket-and-slab" models, in: Carbon Cycling in Northern Peatlands, AGU Geophysical Monograph vol. 184, edited by: Baird, A., Belyea, L., Comas, X., Reeve, A., and Slater, L., 37–53. <a href="http://dx.doi.org/10.1029/2008GM000826">https://doi.org/10.1029/2008GM000826</a>, 2009.

Bauer, I. E., Gignac, L. D., and Vitt, D. H.: Development of a peatland complex in boreal western Canada: Lateral site expansion and local variability in vegetation succession and long-term peat accumulation, Can. J. Bot., 81, 833–847, 2003.

Beilman, D. W., Vitt, D. H., Bhatti, J. S., and Forest, S.: Peat carbon stocks in the southern Mackenzie River Basin: uncertainties revealed in a high-resolution case study, Glob. Change Biol., 14, 1221–1232, <a href="http://dx.doi.org/10.1111/j.1365-2486.2008.01565.x">https://doi.org/10.1111/j.1365-2486.2008.01565.x</a>, 2008.

Belyea, L. R. and Baird, A. J.: Beyond the limits to peat bog growth: cross-scale feedback in peatland development, Ecol. Monogr., 76, 299–322, 2006.

Bhiry, N., Payette, S., and Robert, E.: Peatland development at the arctic tree line (Quebec, Canada) influenced by flooding and permafrost, Quaternary Res., 67, 426–437, 2007.

Botch, M. S., Kobak, K. I., Vinson, T. S., and Kolchugina, T. P.: Carbon pools and accumulation in peatlands of the Former Soviet Union, Global Biogeochem. Cy., 9, 37–46, 1995.

Bridgham, S. D., Megonigal, J. P., Keller, J. K., Bliss, N. B., and Trettin, C.: The carbon balance of North American wetlands, Wetlands, 26, 889–916, 2006.

Brovkin, V., Bendtsen, J., Claussen, M., Ganopolski, A., Kubatzki, C., Petoukhov, V., and Andreev, A.: Carbon cycle, vegetation, and climate dynamics in the Holocene: Experiments with the CLIMBER-2 model, Global Biogeochem. Cy., 16, 1139, <a href="http://dx.doi.org/10.1029/2001GB001662">https://doi.org/10.1029/2001GB001662</a>, 2002.

Campbell, I. D., Campbell, C., Yu, Z. C., Vitt, D. H., and Apps, M. J.: Millennial-scale rhythms in peatlands in the western interior of Canada and in the global carbon cycle, Quaternary Res., 54, 155–158, 2000.

Chapin, F. S., Woodwell, G. M., Randerson, J. T., Rastetter, E. B., Lovett, G. M., Baldocchi, D. D., Clark, D. A., Harmon, M. E., Schimel, D. S., Valentini, R., Wirth, C., Aber, J. D., Cole, J. J., Goulden, M. L., Harden, J. W., Heimann, M., Howarth, R. W., Matson, P. A., McGuire, A. D., Melillo, J. M., Mooney, H. A., Neff, J. C., Houghton, R. A., Pace, M. L., Ryan, M. G., Running, S. W., Sala, O. E., Schlesinger, W. H., and Schulze, E. D.: Reconciling carbon-cycle concepts, terminology, and methods, Ecosystems, 9, 1041–1050, 2006.

Charman, D. J., Beilman, D. W., Blaauw, M., Booth, R. K., Brewer, S., Chambers, F. M., Christen, J. A., Gallego-Sala, A., Harrison, S. P., Hughes, P. D. M., Jackson, S. T., Korhola, A., Mauquoy, D., Mitchell, F. J. G., Prentice, I. C., van der Linden, M., De Vleeschouwer, F., Yu, Z. C., Alm, J., Bauer, I. E., Corish, Y. M. C., Garneau, M., Hohl, V., Huang, Y., Karofeld, E., Le Roux, G., Loisel, J., Moschen, R., Nichols, J. E., Nieminen, T. M., MacDonald, G. M., Phadtare, N. R., Rausch, N., Sillasoo, Ü., Swindles, G. T., Tuittila, E.-S., Ukonmaanaho, L., Väliranta, M., van Bellen, S., van Geel, B., Vitt, D. H., and Zhao, Y.: Climate-related changes in peatland carbon accumulation during the last millennium, Biogeosciences Discuss., 9, 14327–14364, <a href="http://dx.doi.org/10.5194/bgd-9-14327-2012">https://doi.org/10.5194/bgd-9-14327-2012</a>, 2012.

Clymo, R. S.: The limits to peat bog growth, Philos. T. R. Soc. Lon. B, 303, 605–654, 1984.

Clymo, R. S., Turunen, J., and Tolonen, K.: Carbon accumulation in peatland, Oikos, 81, 368–388, 1998.

Couwenberg, J.: A simulation model of mire patterning – revisited, Ecography, 28, 653–661, 2005.

Davidson, E. A. and Janssens, I. A.: Temperature sensitivity of soil carbon decomposition and feedbacks to climate change, Nature, 440, 165–173, 2006.

Dinsmore, K. J., Billett, F. M., Skiba, U. M., Rees, R. M., Drewer, J., and Helfter, C.: Role of the aquatic pathway in the carbon and greenhouse gas budgets of a peatland catchment, Glob. Change Biol., 16, 2750–2762, <a href="http://dx.doi.org/10.1111/j.1365-2486.2009.02119.x">https://doi.org/10.1111/j.1365-2486.2009.02119.x</a>, 2010.

Fraser, C. J. D., Roulet, N. T., and Moore, T. R.: Hydrology and dissolved organic carbon biogeochemistry in an ombrotrophic bog, Hydrol. Process., 15, 3151–3166, 2001.

Frolking, S., Roulet, N. T., Tuittila, E., Bubier, J. L., Quillet, A., Talbot, J., and Richard, P. J. H.: A new model of Holocene peatland net primary production, decomposition, water balance, and peat accumulation, Earth Syst. Dynam., 1, 1–21, <a href="http://dx.doi.org/10.5194/esd-1-1-2010">https://doi.org/10.5194/esd-1-1-2010</a>, 2010.

Frolking, S., Talbot, J., Jones, M. C., Treat, C. C., Kauffman, J. B., Tuittila, E.-S., and Roulet, N.: Peatlands in the Earth's 21st century coupled climate-carbon system, Environ. Rev., 19, 371–396, 2011.

Gajewski, K., Viau, A., Sawada, M., Atkinson, D., and Wilson, S.: Sphagnum peatland distribution in North America and Eurasia during the past 21,000 years, Global Biogeochem. Cy., 15, 297–310, 2001.

Glaser, P. H., Hansen, B. C. S., Siegel, D. I., Reeve, A. S., and Morin, P. J.: Rates, pathways and drivers for peatland development in the Hudson Bay Lowlands, northern Ontario, Canada, J. Ecol., 92, 1036–1053, 2004.

Gorham, E.: Biotic impoverishment in northern peatlands, in: The earth in transition: patterns and processes of biotic impoverishment, edited by: Woodwell, G. M., Cambridge University, New York, NY, 65–98, 1990.

Gorham, E.: Northern peatlands: Role in the carbon cycle and probable responses to climatic warming, Ecol. Appl., 1, 182–195, 1991.

Gorham, E., Lehman, C., Dyke, A., Janssens, J., and Dyke, L.: Temporal and spatial aspects of peatland initiation following deglaciation in North America, Quaternary Sci. Rev., 26, 300–311, 2007.

GSDTG (Global Soil Data Task Group): Global Gridded Surfaces of Selected Soil Characteristics (IGBP-DIS), available at: <a href="http://www.daac.ornl.gov">http://www.daac.ornl.gov</a>, <a href="http://dx.doi.org/10.3334/ORNLDAAC/569">https://doi.org/10.3334/ORNLDAAC/569</a>, 2000.

Halsey, L. A., Vitt, D. H., and Bauer, I. E.: Peatland initiation during the Holocene in continental western Canada, Climatic Change, 40, 315–342, 1998.

Halsey, L., Vitt, D. H., and Gignac, L. D.: Sphagnum-dominated peatlands in North America since the last glacial maximum: Their occurrence and extent, Bryologist, 103, 334–352, 2000.

Harden, J. W., Sundquist, E. T., Stallard, R. F., and Mark, R. K.: Dynamics of soil carbon during deglaciation of the Laurentide ice sheet, Science, 258, 1921–1924, 1992.

Holst, T., Arneth, A., Hayward, S., Ekberg, A., Mastepanov, M., Jackowicz-Korczynski, M., Friborg, T., Crill, P. M., and Bäckstrand, K.: BVOC ecosystem flux measurements at a high latitude wetland site, Atmos. Chem. Phys., 10, 1617–1634, <a href="http://dx.doi.org/10.5194/acp-10-1617-2010">https://doi.org/10.5194/acp-10-1617-2010</a>, 2010.

Ingram, H. A. P.: Size and shape in raised mire ecosystems: a geophysical model, Nature, 297, 300-303, 1982.

Jones, M. C. and Yu, Z. C.: Rapid deglacial and early Holocene expansion of peatlands in Alaska, P. Natl. Acad. Sci. USA, 107, 7347–7352, 2010.

Joosten, H. and Clarke, D.: Wise use of mires and peatlands, International Mire Conservation Group and International Peat Society, Saarijärvi, Finland, 2002.

Kaufman, D. S., Ager, T. A., Anderson, N. J., Anderson, P. M., Andrews, J. T., Bartlein, P. J., Brubaker, L. B., Coats, L. L., Cwynar, L. C., Duvall, M. L., Dyke, A. S., Edwards, M. E., Eisner, W. R., Gajewski, K., Geirsdottir, A., Hu, F. S., Jennings, A. E., Kaplan, M. R., Kerwin, M. W., Lozhkin, A. V., MacDonald, G. M., Miller, G. H., Mock, C. J., Oswald, W. W., Otto-Bliesner, B. L., Porinchu, D. F., Ruhland, K., Smol, J. P., Steig, E. J., and Wolfe, B. B.: Holocene thermal maximum in the western Arctic (0–180° W), Quaternary Sci. Rev., 23, 529–560, 2004.

Kleinen, T., Brovkin, V., von Bloh, W., Archer, D., and Munhoven, G.: Holocene carbon cycle dynamics, Geophys. Res. Lett., 37, L02705, <a href="http://dx.doi.org/10.1029/2009GL041391">https://doi.org/10.1029/2009GL041391</a>, 2010.

Koehler, A.-K., Sottocornola, M., and Kiely, G.: How strong is the current carbon sequestration of an Atlantic blanket bog?, Glob. Change Biol., 17, 309–319, <a href="http://dx.doi.org/10.1111/j.1365-2486.2010.02180.x">https://doi.org/10.1111/j.1365-2486.2010.02180.x</a>, 2011.

Korhola, A.: Radiocarbon evidence for rates of lateral expansion in raised mires in southern Finland, Quaternary Res., 42, 299–307, 1994.

Korhola, A.: Holocene climatic variations in southern Finland reconstructed from peat-initiation data, Holocene, 5, 43–58, 1995.

Korhola, A., Alm, J., Tolonen, K., Turunen, J., and Junger, H.: Three-dimensional reconstruction of carbon accumulation and CH4 emission during nine millennia in a raised mire, J. Quaternary Sci., 11, 161–165, 1996.

Korhola, A., Ruppel, M., Seppä, H., Väliranta, M., Virtanen, T., and Weckström, J.: The importance of northern peatland expansion to the late-Holocene rise of atmospheric methane, Quaternary Sci. Rev., 29, 611–617, 2010.

Kuhry, P. and Turunen, J.: The postglacial development of boreal and subarctic peatlands, in: Boreal Peatland Ecosystems, edited by: Wieder, R. K. and Vitt, D. H., Ecological Studies Series, vol. 188, Springer, New York, 25–46, 2006.

Lappalainen, E.: General review on world peatlands and peat resources, in: Global peat resources, International Peat Society, Jyska, Finland, 53–56, 1996.

Lehner, B. and Döll, P.: Development and validation of a global database of lakes, reservoirs and wetlands, J. Hydrol., 296, 1–22, 2004.

Limpens, J., Berendse, F., Blodau, C., Canadell, J. G., Freeman, C., Holden, J., Roulet, N., Rydin, H., and Schaepman-Strub, G.: Peatlands and the carbon cycle: from local processes to global implications – a synthesis, Biogeosciences, 5, 1475–1491, <a href="http://dx.doi.org/10.5194/bg-5-1475-2008">https://doi.org/10.5194/bg-5-1475-2008</a>, 2008.

Loisel, J., Yu, Z. C., Parkesian, A., Nolan, J. T., and Slater, L. D.: Quantifying landscape morphology influence on peatland lateral expansion using ground penetrating radar (GPR) and peat core analysis, in review, 2012.

Lund, M., Lafleur, P. M., Roulet, N. T., Lindroth, A., Christensen, T. R., Aurela, M., Chojnicki, B. H., Flanagan, L. B., Humphreys, E. R., Laurila, T., Oechel, W. C., Olejnik, J., Rinne, J., Schubert, P., and Nilsson, M. B.: Variability in exchange of CO2 across 12 northern peatland and tundra sites, Glob. Change Biol., 16, 2436–2448, <a href="http://dx.doi.org/10.1111/j.1365-2486.2009.02104.x">https://doi.org/10.1111/j.1365-2486.2009.02104.x</a>, 2010.

MacDonald, G. M., Beilman, D. W., Kremenetski, K. V., Sheng, Y., Smith, L. C., and Valichko, A. A.: Rapid early development of circumarctic peatlands and atmospheric CH4 and CO2 variations, Science, 314, 285–288, 2006.

Malmer, N. and Wallén, B.: Input rates, decay losses and accumulation rates of carbon in bogs during the last millennium: internal processes and environmental changes, Holocene, 14, 111–117, 2004.

Mäkilä, M.: Calculation of the energy content of mires on the basis of peat properties, Geol. S. Finland, Report of Investigation, 121, 1–73, 1994.

Maltby, E. and Immirzi, P.: Carbon dynamics in peatlands and other wetland soils, regional and global perspectives, Chemosphere, 27, 999–1023, 1993.

Matthews, E. and Fung, I.: Methane emission from natural wetlands: Global distribution, area, and environmental characteristics of sources, Global Biogeochem. Cy., 1, 61–86, <a href="http://dx.doi.org/10.1029/GB001i001p00061">https://doi.org/10.1029/GB001i001p00061</a>, 1987.

Menviel, L. and Joos, F.: Toward explaining the Holocene carbon dioxide and carbon isotope records: Results from transient ocean carbon cycle-climate simulations, Paleoceanography, 27, PA1207, <a href="http://dx.doi.org/10.1029/2011PA002224">https://doi.org/10.1029/2011PA002224</a>, 2012.

Moore, P. D.: The future of cool temperate bogs, Environ. Conserv., 29, 3–20, 2002.

Morris, P. J., Belyea, L. R., and Baird, A. J.: Ecohydrological feedbacks in peatland development: a theoretical modeling study, J. Ecol., 99, 1190–1201, 2011.

Nilsson, M., Sagerfors, J., Buffam, I., Laudon, H., Eriksson, T., Grelle, A., Klemedtsson, L., Weslien, P., and Lindroth, A.: Contemporary carbon accumulation in a boreal oligotrophic minerogenic mire – A significant sink after accounting for all C-fluxes, Glob. Change Biol., 14, 2317–2332, <a href="http://dx.doi.org/10.1111/j.1365-2486.2008.01654.x">https://doi.org/10.1111/j.1365-2486.2008.01654.x</a>, 2008.

Post, W. M., Emanuel, W. R., Zinke, P. J., and Stangenberger, A. G.: Soil carbon pools and world life zones, Nature, 298, 156–159, 1982.

Oechel, W. C.: Nutrient and water flux in a small Arctic watershed: an overview, Holarctic Ecol., 12, 229–237, 1989.

Olefeldt, D., Roulet, N. T., Bergeron, O., Crill, P., Bäckstrand, K., and Christensen, T. R.: Net carbon accumulation of a high-latitude permafrost palsa mire similar to permafrost-free peatlands, Geophys. Res. Lett., 39, L03501, <a href="http://dx.doi.org/10.1029/2011GL050355">https://doi.org/10.1029/2011GL050355</a>, 2012.

Riley, J. L.: Peat and peatland resources of Northeastern Ontario, Ontario Geological Survey Miscellaneous Paper, 153, 1–155, 1994.

Riley, J. L.: Wetlands of the Hudson Bay Lowland: An Ontario Overview, Nature Conservancy of Canada, Toronto, ON, 156 pp., 2011.

Roulet, N. T.: Peatlands, carbon storage, greenhouse gases, and the Kyoto protocol: prospecs and significance for Canada, Wetlands, 20, 605–615, 2000.

Roulet, N. T., Lafleur, P. M., Richard, P. J. H., Moore, T. R., Humphreys, E. R., and Bubier, J.: Contemporary carbon balance and late Holocene carbon accumulation in a northern peatland, Glob. Change Biol., 13, 397–411, 2007.

Ruddiman, W. F., Kutzbach, J. E., and Vavrus, S. J.: Can natural or anthropogenic explanations of late-Holocene CO2 and CH4 increases be falsified?, Holocene, 21, 865–879, <a href="http://dx.doi.org/10.1177/0959683610387172">https://doi.org/10.1177/0959683610387172</a>, 2011.

Schlesinger, W. H.: Carbon balance in terrestrial detritus, Annu. Rev. Ecol. Syst., 8, 51–81, 1977.

Schlesinger, W. H.: Soil organic matter: A source of atmospheric CO2, in: The role of terrestrial vegetation in the global carbon cycle, edited by: Woodwell, G. M., Wiley, New York, 111–127, 1984.

Schneider, J., Kutzbach, L., and Wilmking, M.: Carbon dioxide exchange fluxes of a boreal peatland over a complete growing season, Komi Republic, NW Russia, Biogeochemistry, <a href="http://dx.doi.org/10.1007/s10533-011-9684-x">https://doi.org/10.1007/s10533-011-9684-x</a>, in press, 2012.

Sheng, Y., Smith, L. C., MacDonald, G. M., Kremenetski, K. V., Frey, K. E., Velichko, A. A., Lee, M., Beilman, D. W., and Dubinin, P.: A high-resolution GIS-based inventory of the West Siberian peat carbon pool, Global Biogeochem. Cy., 18, GB3004, <a href="http://dx.doi.org/10.1029/2003GB002190">https://doi.org/10.1029/2003GB002190</a>, 2004.

Sjörs, H.: Peat on earth: multiple use or conservation, Ambio, 9, 303–308, 1980.

Sjörs, H.: The zonation of northern peatlands and their importance for the carbon balance of the atmosphere, Int. J. Ecol. Environ. Sci., 7, 11–14, 1981.

Smith, L. C., MacDonald, G. M., Velichko, A. A., Beilman, D. W., Borisova, O. K., Frey, K. E., Kremenetski, K. V., and Sheng, Y.: Siberian peatlands a net carbon sink and global methane source since the Early Holocene, Science, 303, 353–356, 2004.

St. Louis, V., Kelly, C., Duchemin, E., Rudd, J., and Rosenberg, D.: Reservoir surfaces as sources of greenhouse gases to the atmosphere: a global estimate, BioScience, 50, 766–775, 2000.

Sulman, B. N., Desai, A. R., Saliendra, N. Z., Lafleur, P. M., Flanagan, L. B., Sonnentag, O., Mackay, D. S., Barr, A. G., and van der Kamp, G.: CO2 fluxes at northern fens and bogs have opposite responses to inter- annual fluctuations in water table, Geophys. Res. Lett., 37, L19702, <a href="http://dx.doi.org/10.1029/2010GL044018">https://doi.org/10.1029/2010GL044018</a>, 2010.

Syed, K. H., Flanagan, L. B., Carlson, P. J., Glenn, A. J., and van Gaalen, K. E.: Environmental control of net ecosystem CO2 exchange in a treed, moderately rich fen in northern Alberta, Agr. Forest Meteorol., 140, 97–114, 2006.

Tarnocai, C., Kettles, I. M., and Lacelle. B.: Peatlands of Canada, Ottawa, Agriculture and Agri-Food Canada, Research Branch, Ottawa, ON, Canada, 2005.

Tarnocai, C., Canadell, J. G., Schuur, E. A. G., Kuhry, P., Mazhitova, G., and Zimov, S.: Soil organic carbon pools in the northern circumpolar permafrost region, Global Biogeochem. Cy., 23, GB2023, <a href="http://dx.doi.org/10.1029/2008GB003327">https://doi.org/10.1029/2008GB003327</a>, 2009.

Tarnocai, C., Kuhry, P., Broll, G., Ping, C.-L., and Brown, J.: Peatlands and their carbon dynamics: Comment on "Peatlands and their role in the global carbon cycle", Eos, 93, 31, 2012.

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

Turetsky, M. R., Manning, S., and Wieder, R. K.: Dating recent peat deposits, Wetlands, 24, 324–356, 2004.

Turetsky, M. R., Kane, E. S., Harden, J. W., Ottmar, R. D., Manies, K. L., Hoy, E., and Kasischke, E. S.: Recent acceleration of biomass buring and carbon losses in Alaskan forest and peatlands, Nat. Geosci., 4, 27–31, 2011a.

Turetsky, M. R., Donahue, W. F., and Benscoter, B. W.: Experimental drying intensifies burning and carbon losses in a northern peatland, Nat. Commun., 2, 514, <a href="http://dx.doi.org/10.1038/ncomms1523">https://doi.org/10.1038/ncomms1523</a>, 2011b.

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

van Bellen, S., Dallaire, P.-L., Garneau, M., and Bergeron, Y.: Quantifying spatial and temporal Holocene carbon accumulation in ombrotrophic peatlands of the Eastmain region, Quebec, Canada, Global Biogeochem. Cy., 25, GB2016, <a href="http://dx.doi.org/10.1029/2010GB003877">https://doi.org/10.1029/2010GB003877</a>, 2011.

Vitt, D. H., Halsey, L. A., Bauer, I. E., and Campbell C.: Spatial and temporal trends in carbon storage of peatlands of continental western Canada through the Holocene, Can. J. Earth Sci., 37, 683–693, 2000.

Vitt, D. H., Halsey, L. A., and Nicholson, B. J.: The Mackenzie River basin, in: The World's Largest Wetlands: Ecology and Conservation, edited by: Fraser, L. H. and Keddy, P. A., Cambridge University Press, Cambridge, 166–202, 2005.

Waddington, J. M. and Roulet, N. T.: Carbon balance of a boreal patterned peatland, Glob. Change Biol., 6, 87–97, 2000.

Wieder, R. K.: Past, present and future peatland carbon balance – An empirical model based on 210Pb-dated cores, Ecol. Appl., 7, 321–336, 2001.

Yefremov, S. P. and Yefremova, T. T.: Stocks and forms of deposited carbon and nitrogen in bog ecosystems of west Siberia, in: West Siberian Peatlands and Carbon Cycle: Past and Present, edited by: Vasiliev, S. V., Titlyanova, A. A., and Velichko, A. A., Agenstvo Sibprint, Novosibirsk, Russia, 148–151, 2001.

Yu, Z. C.: Holocene carbon accumulation of fen peatlands in boreal western Canada: Complex ecosystem response to climate variation and disturbance, Ecosystems, 9, 1278–1288, 2006.

Yu, Z. C.: Holocene carbon flux histories of the world's peatlands: Global carbon-cycle implications, Holocene, 21, 761–774, 2011.

Yu, Z. C., Beilman, D. W., and Jones, M. C.: Sensitivity of northern peatlands to Holocene climate change, in: Carbon Cycling in Northern Peatlands, edited by: Baird, A., Belyea, L., Comas, X., Reeve, A., and Slater, L., AGU, Geophys. Monog. Series, 184, 55–69, <a href="http://dx.doi.org/10.1029/2008GM000822">https://doi.org/10.1029/2008GM000822</a>, 2009.

Yu, Z. C., Loisel, J., Brosseau, D. P., Beilman, D. W., and Hunt, S. J.: Global peatland dynamics since the Last Glacial Maximum, Geophys. Res. Lett., 37, L13402, <a href="http://dx.doi.org/10.1029/2010GL043584">https://doi.org/10.1029/2010GL043584</a>, 2010.

Yu, Z. C., Beilman, D. W., Frolking, S., MacDonald, G. M., Roulet, R. T., Camill, P., and Charman, D. J.: Peatlands and their role in the global carbon cycle, Eos, American Geophysical Union Transactions, 92, 97–98, 2011.

Yu, Z. C., Beilman, D. W., Frolking, S., MacDonald, G. M., Roulet, R. T., Camill, P., and Charman, D. J.: Peatlands as a model ecosystem of soil carbon dynamics: Reply to comment on "Peatlands and their role in the global carbon cycle", Eos, American Geophysical Union Transactions, 93, 31, 2012a.

Yu, Z. C., Loisel, J., Turetsky, M. R., Cai, S. S., Zhao, Y., Frolking, S., MacDonald, G. M., and Bubier, J. L.: Evidence for elevated emissions from high-latitude wetlands causing high atmospheric CH4 concentration in the early Holocene, in review, 2012b.

Zoltai, S. C.: Estimating the age of peat samples from their weight: a study from west-central Canada, Holocene, 1, 68–73, 1991.

Zoltai, S. C.: Cyclic development of permafrost in the peatlands of northwestern Alberta, Canada, Arctic Alpine Res., 25, 240–246, 1993.

100

Zoltai, S. C., Siltanen, R. M., and Johnson, R. D.: A wetland database for the western boreal, subarctic, and arctic regions of Canada, NOR-X-368, Canadian Forest Service, Northern Forestry Centre, Edmonton, AB, Canada, 2000.