High CO 2 fixation rates in soils haveīeen reportedly associated with higher abundance of obligate autotrophs and Since the transformation ofĬO 2 and release of the fixed carbon via microbial residues vary forĭifferent microbial groups (Berg et al., 2011 Miltner et al., 2005), theĬomposition and abundance of microbial communities play a vital role inĬO 2 fixation rates in soils. Non-living organic material of microbial origin including necromass andĮxtracellular metabolites (Geyer et al., 2020). The biomass of microbial communities serves as the entry point of carbonįixed from CO 2 into SOC, which includes both the intact microbialīiomass carbon (MBC) pool and released microbial residues (Miltner et al.,Ģ004, 2005 Spohn et al., 2019). Genetic potential for both autotrophic and heterotrophic CO 2 fixationĪl., 2005 Šantrůčková et al., 2018) including temperateĮt al., 2022a, 2020 Kaiser et al., 2016). With central microbial metabolism (Erb, 2011). To dark CO 2 fixation via anaplerotic carboxylation reactions associated Heterotrophic bacteria can also contribute Reverse tricarboxylic acid (rTCA) pathwayĮt al., 2016 Liu et al., 2018). Dark CO 2įixation in soils is mediated by chemolithoautotrophic bacteria, largely viaĮt al., 2015 Wu et al., 2014), the Wood–Ljungdahl pathway (WLP), or the Microbes can refix 3 %–6 % of CO 2 in temperateįorest mineral soils before its release to the atmosphereĮt al., 2019), through so-called dark CO 2 fixationĮt al., 2005 Šantrůčková et al., 2018). (SOC) provides one of the largest sources of carbon dioxide ( CO 2) toĢ002 Lal, 2004). ∼36 % occurring in the top 1 m depth of forest soilsīased on the new carbon inventory of the global soil carbon poolĮt al., 2014 Schuur et al., 2015). Most of Earth's terrestrial carbon stock is found in soils, with Temperate forest soils in the future than it does now. Soil respiration and could likely recycle less CO 2 respired from Soils, CO 2 fixation might be less responsive to future warming than net Our findings suggest that in temperate forest The higher rate of microbial residue formation in the beech soil.įurthermore, higher temperatures in general lead to higher microbial Of heterotrophs when compared to the spruce soil hence this might partly explain Soil also had a lower abundance of autotrophs, implying a higher proportion Of the total bacterial community in the beech and spruce soils, the beech Necromass or release of extracellular products). This suggestsĪ primarily higher rate of microbial residue formation (i.e. Than into microbial biomass compared to the spruce soil. Larger fraction of the label CO 2 was fixed into soil organic carbon Respiration might increase 1.16 times more than CO 2 fixation under a Assuming these Q 10 values, we extrapolated that net soil Measured average Q 10 of net soil respiration rates with ∼2.98. Weight was 2.07 for beech and spruce profiles, and this was lower than the TheĪverage Q 10 for dark CO 2 fixation rates normalized to soil dry Rates and derived the Q 10 values for both processes with depth. We used 13C- CO 2 labelling and incubations of soils at 4Īnd 14 ∘C to determine CO 2 fixation and net soil respiration (deciduous) and spruce (coniferous) forest plots of the Hummelshain forest, Respiration rates, we investigated soil profiles to 1 m depth from beech The temperature sensitivity ( Q 10) of dark CO 2 fixation and Respiration in soils of temperate forest regions, is missing. Rates, particularly in comparison to the temperature sensitivity of However, research on the influence of temperature on dark CO 2 fixation Dark CO 2įixation by microbes can recycle some of the released soil CO 2, andĬO 2 fixation rates are reported to increase under higher temperatures. Resulting in important positive feedback on climate change. Potentially increase the release of carbon dioxide ( CO 2) from temperate forest soils, Globally, soil temperature to 1 m depth is predicted to be up to 4 ∘C warmer by the end of this century, with pronounced effectsĮxpected in temperate forest regions.
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