Changing microbial substrate use in Arctic tundra soils through a freeze-thaw cycle

Schimel, Joshua P.; Mikan, Carl J.

doi:10.1016/j.soilbio.2004.12.011

Cited by 170 publications

(148 citation statements)

References 46 publications

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“…Increased active pool size with increased temperature evidenced in this study indicates that at warmer temperatures SOM otherwise unavailable to microbes at lower temperatures becomes available for decomposition. Th is could be attributed to shift s in microbial community composition at diff erent temperatures (Zogg et al, 1997;Zak et al, 1999), changes in substrate use (Andrews et al, 2000;Schimel and Mikan, 2005), or the overcoming of biochemical resistance of SOM by microbes (Conant et al, 2008a).…”

Section: Discussionmentioning

confidence: 99%

The Role of Soil Characteristics on Temperature Sensitivity of Soil Organic Matter

Haddix

Plante

Conant

et al. 2011

Soil Science Soc of Amer J

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T emperature is an important factor controlling SOM turnover and understanding how temperature aff ects SOM decomposition will allow us to better predict how global climate change will aff ect SOM stocks. Understanding the temperature sensitivity of SOM decomposition is challenging because SOM is composed of many diff erent organic C compounds, with diff ering inherent kinetic properties (Davidson and Janssens, 2006). To simplify the process of modeling SOM decomposition, this range of compounds is usually classifi ed into a small number of discrete, kinetically defi ned pools with some portion of SOM being easily decomposable and the rest comprising one or more other pools decomposing more slowly.In most decomposition models, temperature eff ects are modeled as a decomposition rate multiplier for fi xed SOM pools (Lloyd and Taylor, 1994;Del Grosso et al., 2005), but some recent studies have hypothesized that temperature may actually alter the amount of substrate that would be considered easily decomposable (Zogg et al., 1997;Zak et al., 1999;Dalias et al., 2003;Rasmussen et al., 2006). Th e most broadly used terrestrial C models typically have a fi xed Q 10 of 1.5 to 2.0 or an Arrhenius-type function with the same respiration-temperature relationship to each of the diff erent SOM pools (Melillo et al., 1995;Burke et al., 2003;Friedlingstein et al., 2006 Th e uncertainty associated with how projected climate change will aff ect global C cycling could have a large impact on predictions of soil C stocks. Th e purpose of our study was to determine how various soil decomposition and chemistry characteristics relate to soil organic matter (SOM) temperature sensitivity. We accomplished this objective using long-term soil incubations at three temperatures (15, 25, and 35°C) and pyrolysis molecular beam mass spectrometry (py-MBMS) on 12 soils from 6 sites along a mean annual temperature (MAT) gradient (2-25.6°C). Th e Q 10 values calculated from the CO 2 respired during a long-term incubation using the Q 10-q method showed decomposition of the more resistant fraction to be more temperature sensitive with a Q 10-q of 1.95 ± 0.08 for the labile fraction and a Q 10-q of 3.33 ± 0.04 for the more resistant fraction. We compared the fi t of soil respiration data using a two-pool model (active and slow) with fi rst-order kinetics with a three-pool model and found that the two and three-pool models statistically fi t the data equally well. Th e three-pool model changed the size and rate constant for the more resistant pool. Th e size of the active pool in these soils, calculated using the two-pool model, increased with incubation temperature and ranged from 0.1 to 14.0% of initial soil organic C. Sites with an intermediate MAT and lowest C/N ratio had the largest active pool. Pyrolysis molecular beam mass spectrometry showed declines in carbohydrates with conversion from grassland to wheat cultivation and a greater amount of protected carbohydrates in allophanic soils which may have lead to diff erences found between the total...

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Section: Discussionmentioning

confidence: 99%

The Role of Soil Characteristics on Temperature Sensitivity of Soil Organic Matter

Haddix

Plante

Conant

et al. 2011

Soil Science Soc of Amer J

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“…These studies have shown that changes in the near-surface soil freeze/thaw status are interrelated, and soil freeze/thaw affects hydrological processes (Cherkauer and Lettenmaier, 1999;Niu and Yang, 2006;Rempel, 2012), ecological processes (Schimel and Mikan, 2005;Tagesson et al, 2012), and soil microbial processes (Lloyd and Taylor, 1994;Gilichinsky and Wagener, 1995;Edwards and Jefferies, 2013).…”

Section: Introductionmentioning

confidence: 99%

Changes in the timing and duration of the near-surface soil freeze/thaw status from 1956 to 2006 across China

2015

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Abstract. The near-surface soil freeze/thaw status is an important indicator of climate change. Using data from 636 meteorological stations across China, we investigated the changes in the first date, the last date, the duration, and the number of days of the near-surface soil freeze over the period 1956-2006. The results reveal that the first date of the near-surface soil freeze was delayed by about 5 days, or at a rate of 0.10 ± 0.03 day yr −1 , and the last date was advanced by about 7 days, or at a rate of 0.15 ± 0.02 day yr −1 . The duration of the near-surface soil freeze decreased by about 12 days or at a rate of 0.25 ± 0.04 day yr −1 , while the actual number of the near-surface soil freeze days decreased by about 10 days or at a rate of 0.20 ± 0.03 day yr −1 . The rates of changes in the near-surface soil freeze/thaw status increased dramatically from the early 1990s through the end of the study period. Regionally, the changes in western China were greater than those in eastern China. Changes in the nearsurface soil freeze/thaw status were primarily controlled by changes in air temperature, but urbanization may also play an important role.

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“…The Arctic contains about 11% of global soil organic matter (SOM) (Schimel and Mikan, 2005) while those areas referred to as "high-latitude ecosystems" may contain as much as 60% of global SOM (Hobbie et al, 2000). High latitude regions are experiencing the most significant impacts of climate changes (Serreze et al, 2000;Schimel and Mikan, 2005) and this could result in the release of SOM in the future.…”

Section: Introductionmentioning

confidence: 99%

Short term changes of microbial processes in Icelandic soils to increasing temperatures

Guicharnaud

Paton

2010

Biogeosciences

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Abstract. Temperature change is acknowledged to have a significant effect on soil biological processes and the corresponding sequestration of carbon and cycling of nutrients. Soils at high latitudes are likely to be particularly impacted by increases in temperature. Icelandic soils experience unusually frequent freeze and thaw cycles compare to other Arctic regions, which are increasing due to a warming climate. As a consequence these soils are frequently affected by short term temperature fluctuations.In this study, the short term response of a range of soil microbial parameters (respiration, nutrient availability, microbial biomass carbon, arylphosphatase and dehydrogenase activity) to temperature changes was measured in sub-arctic soils collected from across Iceland. Sample sites reflected two soil temperature regimes (cryic and frigid) and two land uses (pasture and arable). The soils were sampled from the field frozen, equilibrated at −20 • C and then incubated for two weeks at −10 • C, −2 • C, +2 • C and +10 • . Respiration and enzymatic activity were temperature dependent. The soil temperature regime affected the soil microbial biomass carbon sensitivity to temperatures. When soils where sampled from the cryic temperature regime a decreasing soil microbial biomass was detected when temperatures rose above the freezing point. Frigid soils, sampled from milder climatic conditions, where unaffected by difference in temperatures. Nitrogen mineralisation did not change with temperature. At −10 • C, dissolved organic carbon accounted for 88% of the fraction of labile carbon which was significantly greater than that recorded at +10 • C when dissolved organic carbon accounted for as low as 42% of the labile carbon fraction.

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Changing microbial substrate use in Arctic tundra soils through a freeze-thaw cycle

Cited by 170 publications

References 46 publications

The Role of Soil Characteristics on Temperature Sensitivity of Soil Organic Matter

The Role of Soil Characteristics on Temperature Sensitivity of Soil Organic Matter

Changes in the timing and duration of the near-surface soil freeze/thaw status from 1956 to 2006 across China

Short term changes of microbial processes in Icelandic soils to increasing temperatures

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