Investigating drivers of microbial activity and respiration in a forested bog

Rewcastle, Kenna E.; Moore, Jessica A. M.; Henning, Jeremiah A.; Mayes, Melanie A.; Patterson, Courtney M.; Wang, Gangsheng; Metcalfe, Daniel B.; Classen, Aimée T.

doi:10.1016/s1002-0160(19)60841-6

Cited by 9 publications

(7 citation statements)

References 52 publications

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“…We covered 135 mesocosms with one of three mesh sizes: 1.45 mm (n = 45), 38 µm (n = 45), or 5 µm (n = 45). We intended to exclude roots from finemesh mesocosms and allow root access to soil with large-mesh mesocosms (Johnson, Leake, & Read, 2001;Langley, Chapman, & Hungate, 2006;Phillips et al, 2012;Rewcastle et al, 2020).…”

Section: Field Studymentioning

confidence: 99%

Plant roots stimulate the decomposition of complex, but not simple, soil carbon

et al. 2020

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Roots release carbon into soil and can alleviate energy limitation of microbial organic matter decomposition. We know little about the effects of roots on microbial decomposition of different organic matter substrates, despite the importance for soil carbon stocks and turnover. Through implementing root–microbe interactions, the Carbon, Organisms, Rhizosphere and Protection in the Soil Environment (CORPSE) model was previously shown to represent dynamics of total soil carbon in temperate forest field experiments. However, the model permits alternative hypotheses concerning microbial‐substrate affinity. We investigated how root inputs affect decomposition of soil organic carbon (SOC) with variable decomposability. We simulated SOC stocks in CORPSE and compared microbial degradation of two substrate types with varying root–microbe interactions under two alternative hypotheses that varied in microbial‐substrate affinity. We compared our modelled hypotheses to a forest field experiment where we quantified decomposition of isotopically labelled starch and leaf tissues in soils with manipulated root access to microbes. We tested the hypothesis that decomposition of leaves would be more sensitive to root inputs than decomposition of starch, corresponding to the alternative model hypotheses. In the field study, leaf decomposition increased with root density, whereas starch decomposition was unchanged by root density. Microbial biomass and enzyme activity consistently increased with root inputs in CORPSE and the field study. Our field experiment supported the CORPSE simulations with high microbial‐substrate affinity. Roots stimulated microbial growth and enzyme production, which increased the degradation of more complex substrates such as leaf tissues. Substrates that were easily decomposed, such as starch, may already be degrading at a maximum rate in the absence of rhizosphere influence because their decomposition rate was unchanged by root inputs. We found that the degree to which roots stimulate microbial decomposition depends on the substrate being decomposed, and that root–microbe interactions influenced SOC stocks in both our model and field experiment. Environmental changes that alter root–microbe interactions could, therefore, alter soil C stocks and biogeochemical cycling, and models of these interactions should incorporate differential influence of rhizosphere inputs on different substrates. A free Plain Language Summary can be found within the Supporting Information of this article.

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Section: Field Studymentioning

confidence: 99%

Plant roots stimulate the decomposition of complex, but not simple, soil carbon

et al. 2020

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“…Climate‐change scenarios assume that prolonged droughts, elevated temperatures, and increased nitrogen (N) deposition (Galloway et al ., 2008) decrease the growth of Sphagnum mosses and increase decay, thus reducing the amount of sequestered C (Limpens et al ., 2011; Norby et al ., 2019). Moreover, changing microbial communities might enhance the functional shift from sink to source (Lew et al ., 2019; Juan‐Ovejero et al ., 2020; Rewcastle et al ., 2020). Together, the impact on global C cycling makes Sphagnum an important ecological model, attracting a growing number of scientists.…”

Section: Introductionmentioning

confidence: 99%

Axenic in vitro cultivation of 19 peat moss (Sphagnum L.) species as a resource for basic biology, biotechnology, and paludiculture

et al. 2020

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“…This is due to the absence of an acrotelm and the decreased water capacity of the peat layer remaining after extraction (as on the dome), as well as to the lack of trees reducing the water supply to the surface through direct interception and limiting evaporation from the surface by shading it. Shrubs have a less stabilising effect on water level fluctuations due to their shallower root system and low potential for hydraulic lift [Lafleur et al, 2005;Rewcastle et al, 2020]. In the summer months, in contrast with the entire warm half of the year, no relationship was found between the water level and the air temperature, which is probably explained by the lower temperature amplitude at the sites during that period.…”

Section: Discussionmentioning

confidence: 99%

Microclimate and Water Conditions of an Extracted and Natural Raised Bog

Zarzycki¹,

Skowera²,

Zając³

2020

J. Ecol. Eng.

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The aim of the study was to assess the hydrological and microclimatic parameters in the areas at different stages of succession after the discontinuation of peat extraction relative to the conditions on a natural raised bog (Orawa-Nowy Targ Basin, Poland). Understanding these conditions is necessary for the effective reclamation of degraded peatlands. Three measurement points were designated in the study area: one on the non-degraded dome of the bog and two in post-mining areas in different stages of succession (Sector A with pine and birch woodland; Sector B with cotton-grass and ericaceous shrubs). Continuous measurements of the water table level, precipitation and air temperature and humidity were performed between May and October in the year 2016. The air temperature throughout the warm half of the year significantly influenced the groundwater levels, as it is the main factor directly affecting evapotranspiration. The effect of the amount of rainfall on the water level proved significant in the post-mining areas, but not significant for the dome of the bog. Under the conditions of an undegraded peat bog, the upper layer, consisting of live and partially decomposed Sphagnum mosses, limits the water level fluctuations by reducing the evaporation from the surface during periods of low water levels, which is caused by a high water storage capacity and reduced infiltration. In advanced stages of secondary forest succession, trees reduce the evapotranspiration from the surface, which reduces fluctuations in the water level; however, by taking up a large amount of water from the deeper layers, they lower it significantly. The greatest effect of the weather conditions on the water level fluctuations occurs at the stage in which the bog is overgrown by shrubs, when there is no natural peat layer, and the impact of shrubs is much smaller than that of trees.

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Investigating drivers of microbial activity and respiration in a forested bog

Cited by 9 publications

References 52 publications

Plant roots stimulate the decomposition of complex, but not simple, soil carbon

Plant roots stimulate the decomposition of complex, but not simple, soil carbon

Axenic in vitro cultivation of 19 peat moss (Sphagnum L.) species as a resource for basic biology, biotechnology, and paludiculture

Microclimate and Water Conditions of an Extracted and Natural Raised Bog

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