Soils isolated during incubation underestimate temperature sensitivity of respiration and its response to climate history

Podrebarac, Frances A.; Laganière, Jérôme; Billings, Sharon A.; Edwards, Kate A.; Ziegler, Susan E.

doi:10.1016/j.soilbio.2015.10.012

Cited by 21 publications

(33 citation statements)

References 43 publications

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“…Warming and drying trends in the boreal regions that inhibit moss growth (Gower et al, 2001;Turetsky, 2003) could result in the formation of SOM comprised of a greater relative abundance of vascular plant tissues, and thus of SOM that is both more decomposable and more temperature sensitive. This is consistent with our observations of increasing temperature sensitivity of soil respiration at lower latitudes along this boreal forest transect where moss inputs are reduced (Podrebarac et al 2016 …”

Section: Decomposition Of Mosses Is Slower and Less Temperature Sensisupporting

confidence: 93%

“…The SR mosses, but not the GC mosses, exhibited higher Q10 than the bulk L horizon soil (Laganière et al, 25 2015;Podrebarac et al, 2016) and previous findings for vascular plant tissue decomposition (e.g. Fierer et al 2005) based on the decay rate of the labile C fraction.…”

Section: Decomposition Of Mosses Is Slower and Less Temperature Sensisupporting

confidence: 53%

“…Despite having the highest contribution of mosses to the organic horizon, the coolest region in the transect had the highest specific soil respiration rate (R10) and similar or lower Q10 compared to the other regions (Laganière et al, 2015;Podrebarac et al, 2016). The slow decomposition of moss 20 tissues therefore does not appear to slow decomposition in moss-rich organic soils.…”

Section: Implications For the Bioavailability Of Boreal Forest Sommentioning

confidence: 96%

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Biochemical and structural controls on the decomposition dynamics of boreal upland forest moss tissues

Philben¹,

Butler²,

Billings³

et al. 2018

Preprint

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Abstract.Mosses contribute an average of 20% of upland boreal forest net primary productivity and are frequently observed to degrade slowly compared to vascular plants. If this is caused primarily by the chemically complexity of their tissues, moss decomposition could exhibit high temperature sensitivity (measured as Q10) due to high activation energy, which would imply soil organic carbon (SOC) stocks derived from moss remains are especially vulnerable to decomposition with warming. Alternatively, the physical structure of the moss cell wall biochemical matrix could 20 inhibit decomposition, resulting in low decay rates and low temperature sensitivity. We tested these hypotheses by incubating mosses collected from two boreal forests in Newfoundland, Canada, for 959 days at 5 and 18°C, while monitoring changes in the moss tissue composition using total hydrolysable amino acid (THAA) analysis and 13 C NMR spectroscopy. Less than 40% of C was respired in all incubations, revealing a large pool of apparently recalcitrant C. The decay rate of the labile fraction increased in the warmer treatment, but the total amount of C loss 25 increased only slightly, resulting in low Q10 values (1.23-1.33) compared to L horizon soils collected from the same forests. NMR spectra were dominated by O-alkyl C throughout the experiment, indicating the persistence of potentially labile C. Accumulation of hydroxyproline (derived primarily from plant cell wall proteins) and aromatic C indicates selective preservation of biochemicals associated with the moss cell wall. This was supported by scanning electron microscope (SEM) images of the moss tissues, which revealed few changes in the physical structure of the 30 cell wall after incubation. This suggests the moss cell wall matrix protected labile C from microbial decomposition, accounting for the low temperature sensitivity of moss decomposition despite low decay rates. Climate drivers of moss biomass and productivity, therefore, represent a potentially important regulator of boreal forest SOC responses to climate change that needs to be assessed to improve our understanding of carbon-climate feedbacks.

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Section: Decomposition Of Mosses Is Slower and Less Temperature Sensisupporting

confidence: 93%

Section: Decomposition Of Mosses Is Slower and Less Temperature Sensisupporting

confidence: 53%

Section: Implications For the Bioavailability Of Boreal Forest Sommentioning

confidence: 96%

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Biochemical and structural controls on the decomposition dynamics of boreal upland forest moss tissues

Philben¹,

Butler²,

Billings³

et al. 2018

Preprint

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“…We used this knowledge and prior successful use of soil temperature with controlled soil moisture conditions to predict soil CO 2 efflux (Lavigne et al, 2003). Combining this information with site specific temperature responses derived from soil incubation results (Podrebarac et al, 2016), we applied soil temperature records to estimate the total soil CO 2 flux for snow-free periods at the northern-most ER sites, where frequent CO 2 flux measurements were not possible. We also applied this technique to estimate total soil CO 2 flux for snow-free periods at the additional uninstrumented SR and GC sites, using site-specific temperature-response models generated from data collected at both SR-1 and GC-1 (see Supplemental Information).…”

Section: Total Soil Co 2 Flux Measuresmentioning

confidence: 99%

Climate Warming Can Accelerate Carbon Fluxes without Changing Soil Carbon Stocks

et al. 2017

Self Cite

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“…Q 10 evaluation is usually based on instantaneous CO 2 flux rates (Chang et al, 2012;Fang and Moncrieff, 2001;Karhu et al, 2014;Sun et al, 2016;Waldrop et al, 2010), time spans needed for an identical amount of C mineralization (Bracho et al, 2016;Wang et al, 2013;Zhu and Cheng, 2011), cumulative C flux over a given time period (Conant et al, 2008;Hamdi et al, 2013;Podrebarac et al, 2016), or microbial activity as a function of temperature (Diakova et al, 2016;Karhu et al, 2014).…”

Section: Introductionmentioning

confidence: 99%

Q10 values vary with different kinetic properties of C mineralization

Bai

Lin

et al. 2017

Pedobiologia

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A B S T R A C TTemperature response quotient (Q 10 ) is a critical parameter for evaluating global additional carbon (C) release with climate change. However, its value is usually derived from time span or instantaneous rate or cumulative amount of C flux, giving a very one-sided account of thermal sensitivity of C cycling. Through a 117-day laboratory incubation study, we estimated Q 10 values simultaneously with the labile (a 0 ) and recalcitrant C proportions and their rate constants, and then tested for any variances of these kinetic properties in different vegetation stands, soil horizons, aeration statuses, and thermal settings (i.e., diurnally-varying, constant low and constant high temperatures). A regularly varying temperature regime increased the exploitation of labile C resources (i.e., high a 0 ) and required longer time spans (i.e., low rate constants). The constant high temperature induced the exhaustive depletion of the labile C pool and motivated a very rapid and short-term C mineralization process. The constant low temperature treatment was characterized by the lowest a 0 but by medium rate constants because low temperature slowed the C mineralization processes but retained high level of the original C processing diversity. Therefore, a 0 and the rate constants showed discrepancies in their temperature sensitivities as revealed by pairwise comparisons of temperature regimes. Such discrepancies were also supported by pairwise comparisons of aeration statuses, forest stands and soil horizons. The Q 10 bias between C mineralization a 0 and rate constants in this laboratory experiment is attributed to the inherently distinct properties of these two parameters, as a 0 and its Q 10 are closely correlated with the sizes of the easily available C pool, while rate constants and their Q 10 variances explain the temporal scale of the same C mineralization process. Our findings suggest a combined application of a 0 and rate constants for exploring the temperature sensitivity of C mineralization in future studies.

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Soils isolated during incubation underestimate temperature sensitivity of respiration and its response to climate history

Cited by 21 publications

References 43 publications

Biochemical and structural controls on the decomposition dynamics of boreal upland forest moss tissues

Biochemical and structural controls on the decomposition dynamics of boreal upland forest moss tissues

Climate Warming Can Accelerate Carbon Fluxes without Changing Soil Carbon Stocks

Q10 values vary with different kinetic properties of C mineralization

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