Mean residence time of O horizon carbon along a climatic gradient in Scandinavia estimated by 14C measurements of archived soils

Fröberg, Mats; Tipping, Edward; Stendahl, Johan; Clarke, Nicholas; Bryant, Charlotte

doi:10.1007/s10533-010-9497-3

Cited by 35 publications

(33 citation statements)

References 29 publications

(21 reference statements)

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“…The opposite tendencies in early and later stages of the decomposition process make the long-term result on soil carbon storage and carbon circulation less evident. Relatively similar humus layer mean ages were reported for the Swedish North and South as calculated from C 14 determinations (Fröberg et al 2011). This indicates that the heterogeneous humus layer materials have reached similar degrees of decomposition in this geographical range in spite of geographic differences in both early and late phases of decomposition.…”

Section: Discussionsupporting

confidence: 71%

“…This indicates that the heterogeneous humus layer materials have reached similar degrees of decomposition in this geographical range in spite of geographic differences in both early and late phases of decomposition. Thus, the magnitude of litter inputs rather than decay will be decisive for the soil carbon store, as also suggested by Prescott (2005); Fröberg et al (2011).…”

Section: Discussionmentioning

confidence: 70%

“…Humus layers are mixed materials of various ages and stages of decomposition. Results of a 14 C measurement study byFröberg et al 2011 on carbon residence time in the humus layer along a climatic gradient in Scandinavia did not find large differences in the average age of humus layers between northern (ca. 41 years old), middle (ca.…”

mentioning

confidence: 89%

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Long-Term Monitoring of Scots Pine Litter Decomposition Rates Throughout Sweden Indicates Formation of a More Recalcitrant Litter in the South

Bringmark¹,

Sonesten²,

Mjöfors³

et al. 2011

AMBIO

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Decomposition studies were carried out at sites throughout Sweden, including the four Integrated Monitoring sites. Scots pine needle litterbag weight loss measurements over 3 or 5 years were determined at 26 sites and repeated up to 27 times, depending on the site. Humus layer respiration rates were determined for 20 sites in 1987-1989 and repeated in 2007-2008. Partial Least Squares (PLS) regression was used to elucidate the relative importance of climatic and soil factors. Annual needle weight losses decreased only slowly (20-10%) over 3-5 years for all northern (>60°N) sites but decreased sharply from 30 to 10% in the third year in southern (<60°N) sites. Respiration rates of southern sites were less (40% on average) than those of northern sites. Humus layer N was positively correlated to needle weight loss during the first and the second years, but negatively correlated in the third year and to respiration rates. The results indicated that litter formed in southern Sweden became more recalcitrant in later stages of decomposition compared to litter produced in northern Sweden.

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Section: Discussionsupporting

confidence: 71%

Section: Discussionmentioning

confidence: 70%

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Long-Term Monitoring of Scots Pine Litter Decomposition Rates Throughout Sweden Indicates Formation of a More Recalcitrant Litter in the South

Bringmark¹,

Sonesten²,

Mjöfors³

et al. 2011

AMBIO

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“…C values due to the incorporation of bomb-derived 14 C into surface decadal OC pools (40). These calculations suggest that the magnitude of permafrost carbon release, which may be masked or muted by other Arctic OC pools, is relevant on regional to continental scales.…”

mentioning

confidence: 82%

“…It is notable that at zero runoff rate (representing extreme base flow with minimum detrital input), regression analysis yields an endmember Δ 14 C value of −655‰ for lignin phenols, similar to that of plant wax lipids in the westernmost (Kalix) estuary. Assuming that surface detrital carbon has decadal turnover times in the high latitudes (39,40), and hence a Δ 14 C value of +100 to +200‰, whereas deep soil-derived lignin has a Δ 14 C value of −655‰, we estimate from a binary mixing model (Table S3) that ∼30-90% of mobilized lignin across the Eurasian Arctic reflects modern carbon sources.…”

mentioning

confidence: 99%

Differential mobilization of terrestrial carbon pools in Eurasian Arctic river basins

Feng

Vonk

Dongen

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

193

226

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Mobilization of Arctic permafrost carbon is expected to increase with warming-induced thawing. However, this effect is challenging to assess due to the diverse processes controlling the release of various organic carbon (OC) pools from heterogeneous Arctic landscapes. Here, by radiocarbon dating various terrestrial OC components in fluvially and coastally integrated estuarine sediments, we present a unique framework for deconvoluting the contrasting mobilization mechanisms of surface vs. deep (permafrost) carbon pools across the climosequence of the Eurasian Arctic. Vascular plant-derived lignin phenol 14 C contents reveal significant inputs of young carbon from surface sources whose delivery is dominantly controlled by river runoff. In contrast, plant wax lipids predominantly trace ancient (permafrost) OC that is preferentially mobilized from discontinuous permafrost regions, where hydrological conduits penetrate deeper into soils and thermokarst erosion occurs more frequently. Because river runoff has significantly increased across the Eurasian Arctic in recent decades, we estimate from an isotopic mixing model that, in tandem with an increased transfer of young surface carbon, the proportion of mobilized terrestrial OC accounted for by ancient carbon has increased by 3–6% between 1985 and 2004. These findings suggest that although partly masked by surface carbon export, climate change-induced mobilization of old permafrost carbon is well underway in the Arctic.

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Strong regional atmospheric ¹⁴C signature of respired CO₂ observed from a tall tower over the midwestern United States

et al. 2016

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Radiocarbon in CO2 (14CO2) measurements can aid in discriminating between fast (<1 year) and slower (>5–10 years) cycling of C between the atmosphere and the terrestrial biosphere due to the 14C disequilibrium between atmospheric and terrestrial C. However, 14CO2 in the atmosphere is typically much more strongly impacted by fossil fuel emissions of CO2, and, thus, observations often provide little additional constraints on respiratory flux estimates at regional scales. Here we describe a data set of 14CO2 observations from a tall tower in northern Wisconsin (USA) where fossil fuel influence is far enough removed that during the summer months, the biospheric component of the 14CO2 budget dominates. We find that the terrestrial biosphere is responsible for a significant contribution to 14CO2 that is 2–3 times higher than predicted by the Carnegie‐Ames‐Stanford approach terrestrial ecosystem model for observations made in 2010. This likely includes a substantial contribution from the North American boreal ecoregion, but transported biospheric emissions from outside the model domain cannot be ruled out. The 14CO2 enhancement also appears somewhat decreased in observations made over subsequent years, suggesting that 2010 may be anomalous. With these caveats acknowledged, we discuss the implications of the observation/model comparison in terms of possible systematic biases in the model versus short‐term anomalies in the observations. Going forward, this isotopic signal could be exploited as an important indicator to better constrain both the long‐term carbon balance of terrestrial ecosystems and the short‐term impact of disturbance‐based loss of carbon to the atmosphere.

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Mean residence time of O horizon carbon along a climatic gradient in Scandinavia estimated by 14C measurements of archived soils

Cited by 35 publications

References 29 publications

Long-Term Monitoring of Scots Pine Litter Decomposition Rates Throughout Sweden Indicates Formation of a More Recalcitrant Litter in the South

Long-Term Monitoring of Scots Pine Litter Decomposition Rates Throughout Sweden Indicates Formation of a More Recalcitrant Litter in the South

Differential mobilization of terrestrial carbon pools in Eurasian Arctic river basins

Strong regional atmospheric ¹⁴C signature of respired CO₂ observed from a tall tower over the midwestern United States

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Mean residence time of O horizon carbon along a climatic gradient in Scandinavia estimated by 14C measurements of archived soils

Cited by 35 publications

References 29 publications

Long-Term Monitoring of Scots Pine Litter Decomposition Rates Throughout Sweden Indicates Formation of a More Recalcitrant Litter in the South

Long-Term Monitoring of Scots Pine Litter Decomposition Rates Throughout Sweden Indicates Formation of a More Recalcitrant Litter in the South

Differential mobilization of terrestrial carbon pools in Eurasian Arctic river basins

Strong regional atmospheric 14C signature of respired CO2 observed from a tall tower over the midwestern United States

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Strong regional atmospheric ¹⁴C signature of respired CO₂ observed from a tall tower over the midwestern United States