Net carbon accumulation of a high‐latitude permafrost palsa mire similar to permafrost‐free peatlands

Abstract

Palsa mires, nutrient poor permafrost peatlands common in subarctic regions, store a significant amount of carbon (C) and it has been hypothesized their net ecosystem C balance (NECB) is sensitive to climate change. Over two years we measured the NECB for Stordalen palsa mire and found it to accumulate 46 g C m−2 yr−1. While Stordalen NECB is comparable to nutrient poor peatlands without permafrost, the component fluxes differ considerably in magnitude. Specifically, Stordalen had both lower growing season CO2 uptake and wintertime CO2losses, but importantly also low dissolved organic carbon exports and hydrocarbon (mainly methane) emissions. Restricted C losses from palsa mires are likely to have facilitated C accumulation of unproductive subarctic permafrost peatlands. Continued climate change and permafrost thaw is likely to amplify several component fluxes, with an uncertain overall effect on NECB – highlighting the necessity for projections of high‐latitude C storage to consider all C fluxes.

Aquatic DOC export from subarctic Atlantic blanket bog in Norway is controlled by seasalt deposition, temperature and precipitation

“…may be considerably overestimated when components of the net ecosystem carbon balance (NECB; Chapin et al 2006) are not accounted for, including lateral aquatic export of dissolved organic carbon (DOC) and particulate organic carbon, dissolved inorganic carbon (DIC and CO 2 ) and methane fluxes Olefeldt et al 2012;Randerson et al 2002;Roulet et al 2007;Yu 2012). This is especially important in northern peatlands, which are among the largest terrestrial carbon stores (Gorham 1991;Yu 2012).…”

“…There are a few examples of complete or nearly complete NECBs for peatlands, where net ecosystem exchange (NEE), methane fluxes and aquatic carbon fluxes have all been quantified (Dinsmore et al 2010;Juutinen et al 2013;Koehler et al 2011;Nilsson et al 2008;Olefeldt et al 2012;Roulet et al 2007). Many more studies have quantified NEE for peatlands, but not aquatic carbon export, i.e., in subarctic (Aurela et al 2002;Lund et al 2015), boreal (Aurela et al 2007(Aurela et al , 2009Peichl et al 2014;Sagerfors et al 2008), tropical (Hirano et al 2012;Mezbahuddin et al 2014), and temperate peatlands (Beetz et al 2013;Campbell et al 2014;Elsgaard et al 2012;Lund et al 2007;McVeigh et al 2014).…”

ORCHIDEE-PEAT (revision 4596), a model for northern peatland CO<sub>2</sub>, water, and energy fluxes on daily to annual scales

“…CH 4 fluxes and DOC loss through runoff are important components of the carbon balance of a peatland (Chu et al, 2014;Olefeldt et al, 2012) but are not included in this study. This new peat model is incorporated consistently into the land surface scheme in order to conserve water, carbon, and energy at scales from local sites to grid-based largescale applications in an Earth system modeling context.…”

Shifting environmental controls on CH<sub>4</sub> fluxes in a sub-boreal peatland

“…Moreover, peatland ecosystems currently sequester an estimated 76 Tg (10 12 g) C −1 yr −1 (Vasander and Kettunen, 2006;Zoltai and Martikainen, 1996). Peatlands are also a significant source of methane (CH 4 ) because of the anaerobic conditions in the often saturated peat (Olefeldt et al, 2012;Roulet, 2000;Turetsky et al, 2002;Turetsky et al, 2008b;Zhuang et al, 2007). However, because many of the world's peatlands are located in northern climates where temperature and precipitation are expected to experience rapid change (IPCC, 2007;Räisänen, 1997), the fate of the stored carbon in peatlands is now in question (e.g.…”