Amplified carbon release from vast West Siberian peatlands by 2100

Abstract

[1] Extensive new data from previously unstudied Siberian streams and rivers suggest that mobilization of currently frozen, high-latitude soil carbon is likely over the next century in response to predicted Arctic warming. We present dissolved organic carbon (DOC) measurements from ninety-six watersheds in West Siberia, a region that contains the world's largest stores of peat carbon, exports massive volumes of freshwater and DOC to the Arctic Ocean, and is warming faster than the Arctic as a whole. The sample sites span $10 6 km 2 over a large climatic gradient ($55-68°N), providing data on a much broader spatial scale than previous studies and for the first time explicitly examining stream DOC in permafrost peatland environments. Our results show that cold, permafrostinfluenced watersheds release little DOC to streams, regardless of the extent of peatland cover. However, we find considerably higher concentrations in warm, permafrost-free watersheds, rising sharply as a function of peatland cover. The two regimes are demarcated by the position of the À2°C mean annual air temperature (MAAT) isotherm, which is also approximately coincident with the permafrost limit. Climate model simulations for the next century predict near-doubling of West Siberian land surface areas with a MAAT warmer than À2°C, suggesting up to $700% increases in stream DOC concentrations and $2.7-4.3 Tg yr À1 ($29 -46%) increases in DOC flux to the Arctic Ocean.

Decadal oscillations of the aquatic chemistry of river waters in Latvia

“…Signs of oscillations with 20, 11, 8-9, 3-5 and 2 years long periods can be observed, that generally corresponds to the results of earlier studies (Glazacheva, 1988;Klavins et al, 2002a). Increase of water color, known also as brownification, was frequently reported in many lakes and rivers of the Northern hemisphere (Driscoll et al, 2003;Frey and Smith, 2005;Monteith et al, 2007;Erlandsson et al, 2008;Haaland et al, 2010), including Latvian rivers as well (Klavins et al, 2012). Our data show that despite low data quality and short period of observations , statistically significant upward trends of color values can be found in both rivers (Table 3).…”

Peatland hydrology and carbon release: why small-scale process matters

“…These Siberian peats potentially hold 70 billion tonnes of CH 4 , a quarter of all CH 4 stored around the world. These thawed Siberian peats have also been shown to release substantially more DOC in rivers than where the permafrost remains intact (Frey & Smith 2005).…”

Soil temperature response to 21st century global warming: the role of and some implications for peat carbon in thawing permafrost soils in North America

“…The net effect of warming will depend on the balance of increased respiration and productivity Dorrepaal et al, 2009) as a result of warmer soils, and increased export of dissolved organic carbon (DOC) in rivers and streams in catchments with thawed peatlands (Frey and Smith, 2005).…”

“…This relatively large carbon pool within Correspondence to: D. Wisser (dominik.wisser@unh.edu @) one to a few meters of the land surface confers the important role of peatlands in the earth's carbon fluxes (Gorham, 1991). Changing environmental conditions could potentially impact the exchanges of carbon dioxide (CO 2 , Limpens et al, 2008), methane (CH 4 , Christensen et al, 2004), dissolved organic carbon (DOC, Frey and Smith, 2005) and nitrous oxide (N 2 O, Elberling et al, 2010) between peatlands and the atmosphere through a number of direct and indirect effects, and thereby change the role of peatlands in the global climate system. In particular, climate warming can directly affect C fluxes from peatlands.…”