Root control of fungal communities and soil carbon stocks in a temperate forest

Whalen, Emily D.; Lounsbury, Natalie P.; Geyer, Kevin M.; Anthony, Mark; Morrison, Eric W.; Diepen, Linda T. A. van; Moine, J. Le; Nadelhoffer, Knute J.; Enden, Lori vanden; Simpson, Myrna J.; Frey, Serita D.

doi:10.1016/j.soilbio.2021.108390

Cited by 18 publications

(11 citation statements)

References 128 publications

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“…This mechanism can also explain the increased GP‐to‐GN ratio under litter removal, as most Gram‐positive bacteria are oligotrophic communities and can use more recalcitrant C sources from SOM like fungi (Kramer & Gleixner, 2008; Zechmeister‐Boltenstern et al, 2015). Beyond reducing belowground C inputs by root exclusion, root removal can also directly decrease the biomass of symbiotic fungi (e.g., arbuscular mycorrhizal and ectomycorrhizal fungi) associated with plant roots (Dove et al, 2019; Whalen et al, 2021). Therefore, root removal induced larger negative effects on fungi than bacteria (24.8%, 95% CI: 16.2%–32.4% vs. 13.9%, 95% CI: 6.6%–20.6%; p = .049), and consequently decreased fungal‐to‐bacterial ratio (Figure 2c).…”

Section: Discussionmentioning

confidence: 99%

“…Similar to litter addition, litter removal also increased fungal-to-bacterial ratio, likely because litter removal caused continuous losses of soil labile C (Figures 2 and 6b; Lajtha, Townsend, et al, 2014), and fungi can produce oxidative enzymes more efficiently than bacteria to decompose recalcitrant C to maintain their growth (Cusack et al, 2011). This mechanism can also explain the increased GP-to-GN ratio under litter removal, as most Gram-positive bacteria are oligotrophic communities and can use more recalcitrant C sources from SOM like fungi (Kramer reducing belowground C inputs by root exclusion, root removal can also directly decrease the biomass of symbiotic fungi (e.g., arbuscular mycorrhizal and ectomycorrhizal fungi) associated with plant roots (Dove et al, 2019;Whalen et al, 2021). Therefore, root removal induced larger negative effects on fungi than bacteria (24.8%, 95% CI: 16.2%-32.4% vs. 13.9%, 95% CI: 6.6%-20.6%; p = .049), and consequently decreased fungal-to-bacterial ratio (Figure 2c).…”

Section: Soil Microbial Community Responsesmentioning

confidence: 99%

“…However, these two studies only included aboveground litter alterations (addition and removal) and mainly focused on bulk SOC, and half of the observations were from grasslands and croplands (Xu, Liu, et al, 2013, 2021). Global changes can alter both above‐ and belowground plant inputs via regulating plant productivity and C allocation, which, thus, can affect soil C and microbial communities via changing plant inputs into the soil (Figure 1; Lajtha, Townsend, et al, 2014; Whalen et al, 2021). However, neither of these two meta‐analyses considers belowground root alterations (Xu, Liu, et al, 2013, 2021).…”

Section: Introductionmentioning

confidence: 99%

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Changes in plant inputs alter soil carbon and microbial communities in forest ecosystems

Feng

Zhang

et al. 2022

Global Change Biology

106

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Global changes can alter plant inputs from both above-and belowground, which, thus, may differently affect soil carbon and microbial communities. However, the general patterns of how plant input changes affect them in forests remain unclear. By conducting a meta-analysis of 3193 observations from 166 experiments worldwide, we found that alterations in aboveground litter and/or root inputs had profound effects on soil carbon and microbial communities in forest ecosystems. Litter addition stimulated soil organic carbon (SOC) pools and microbial biomass, whereas removal of litter, roots or both (no inputs) decreased them. The increased SOC under litter addition suggested that aboveground litter inputs benefit SOC sequestration despite accelerated decomposition. Unlike root removal, litter alterations and no inputs altered particulate organic carbon, whereas all detrital treatments did not significantly change mineral-associated organic carbon. In addition, detrital treatments contrastingly altered soil microbial community, with litter addition or removal shifting it toward fungi, whereas root removal shifting it toward bacteria. Furthermore, the responses of soil carbon and microbial biomass to litter alterations positively correlated with litter input rate and total litter input, suggesting that litter input quantity is a critical controller of belowground processes. Taken together, these findings provide critical insights into understanding how altered plant productivity and allocation affects soil carbon cycling, microbial communities and functioning of forest ecosystems under global changes. Future studies can take full advantage of the existing plant detritus experiments and should focus on the relative roles of litter and roots in forming SOC and its fractions.

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Section: Discussionmentioning

confidence: 99%

Section: Soil Microbial Community Responsesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Changes in plant inputs alter soil carbon and microbial communities in forest ecosystems

Feng

Zhang

et al. 2022

Global Change Biology

106

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“…Plant root exudates can also stimulate microbial metabolism and prime organic matter degradation, a phenomenon observed in laboratory studies of permafrost (Wild et al, 2016). In temperate systems the rhizosphere is a zone where stochastic processes dominate (Beck et al, 2015; Whalen et al, 2021); if applicable to the new rooting zone of plants following permafrost thaw, this will bring another degree of stochasticity into the system. Permafrost thaw releases dissolved N (Finger et al, 2016; Salmon et al, 2018), and the outcome of plant and microbial competition for N is an important determinant of the post‐thaw microbiome (Finger et al, 2016), which can also impact ecosystem‐scale processes such as N 2 O flux (Voigt et al, 2017).…”

Section: Space and Time Direct Deterministic Versus Stochastic Assemblymentioning

confidence: 99%

Microbiome assembly in thawing permafrost and its feedbacks to climate

Ernakovich

Barbato

Rich

et al. 2022

Global Change Biology

Self Cite

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The physical and chemical changes that accompany permafrost thaw directly influence the microbial communities that mediate the decomposition of formerly frozen organic matter, leading to uncertainty in permafrost-climate feedbacks. Although changes to microbial metabolism and community structure are documented following thaw, the generality of post-thaw assembly patterns across permafrost soils of the world remains uncertain, limiting our ability to predict biogeochemistry and microbial community responses to climate change. Based on our review of the Arctic microbiome, permafrost microbiology, and community ecology, we propose that Assembly Theory provides a framework to better understand thaw-mediated microbiome changes and the implications for community function and climate feedbacks. This framework posits that the prevalence of deterministic or stochastic processes indicates whether the community is well-suited to thrive in changing environmental conditions. We predict that on a short timescale and following high-disturbance thaw (e.g., thermokarst), stochasticity dominates post-thaw microbiome assembly, suggesting that functional predictions will be aided by detailed information about the microbiome. At a longer timescale and lower-intensity disturbance (e.g., active layer deepening), deterministic processes likely dominate, making environmental parameters sufficient for predicting function. We propose that the contribution of stochastic and deterministic processes to post-thaw microbiome assembly depends on the characteristics of the thaw disturbance, as well as characteristics of the microbial community, such as the ecological and phylogenetic breadth of functional guilds, their functional redundancy, and biotic interactions. These propagate across space and time, potentially providing a means for predicting the microbial forcing of greenhouse gas feedbacks to global climate change.

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“…Furthermore, compared with mineral soil layers, higher microbial biomass has been reported in forest floor layers in stands of birch (Mundra et al ., 2021) and other tree species (Baldrian et al ., 2013). In contrast, effects of different tree species in the mineral soil has been suggested to be mainly driven by direct microbial interactions with roots (Whalen et al ., 2021) or by microorganisms utilizing tree species‐specific root exudates (Bais et al ., 2006), and may further be governed by variation in local soil chemistry (Tedersoo et al ., 2015). Soil processes, soil properties and microbial communities are depth‐dependent, and for a more complete understanding, studies on soil characteristics beyond the surface layer are needed (Yost & Hartemink, 2020), including comparisons of microbial communities at different soil depths.…”

Section: Introductionmentioning

confidence: 99%

Shift in tree species changes the belowground biota of boreal forests

et al. 2022

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Summary The replacement of native birch with Norway spruce has been initiated in Norway to increase long‐term carbon storage in forests. However, there is limited knowledge on the impacts that aboveground changes will have on the belowground microbiota. We examined which effects a tree species shift from birch to spruce stands has on belowground microbial communities, soil fungal biomass and relationships with vegetation biomass and soil organic carbon (SOC). Replacement of birch with spruce negatively influenced soil bacterial and fungal richness and strongly altered microbial community composition in the forest floor layer, most strikingly for fungi. Tree species‐mediated variation in soil properties was a major factor explaining variation in bacterial communities. For fungi, both soil chemistry and understorey vegetation were important community structuring factors, particularly for ectomycorrhizal fungi. The relative abundance of ectomycorrhizal fungi and the ectomycorrhizal : saprotrophic fungal ratio were higher in spruce compared to birch stands, particularly in the deeper mineral soil layers, and vice versa for saprotrophs. The positive relationship between ergosterol (fungal biomass) and SOC stock in the forest floor layer suggests higher carbon sequestration potential in spruce forest soil, alternatively, that the larger carbon stock leads to an increase in soil fungal biomass.

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Root control of fungal communities and soil carbon stocks in a temperate forest

Cited by 18 publications

References 128 publications

Changes in plant inputs alter soil carbon and microbial communities in forest ecosystems

Changes in plant inputs alter soil carbon and microbial communities in forest ecosystems

Microbiome assembly in thawing permafrost and its feedbacks to climate

Shift in tree species changes the belowground biota of boreal forests

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