Flux and turnover of fixed carbon in soil microbial biomass of limed and unlimed plots of an upland grassland ecosystem

Rangel‐Castro, J. Ignacio; Prosser, Jim; Ostle, Nicholas J.; Scrimgeour, C. M.; Killham, Ken; Meharg, Andrew A.

doi:10.1111/j.1462-2920.2005.00722.x

Cited by 33 publications

(23 citation statements)

References 50 publications

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“…Experiments by Ostle et al (2003) and Rangel-Castro et al (2005a) demonstrated rapid allocation and incorporation of recently photosynthesized 13 C into soil microbial biomass. Labelled C is incorporated within hours and the half life of microbial pools of 13 C was calculated to be 4.7 days.…”

Section: Carbon Flow To Mycorrhizal and Bacterial Symbiontsmentioning

confidence: 97%

Carbon flow in the rhizosphere: carbon trading at the soil–root interface

Jones

Nguyen²,

Finlay³

2009

Plant Soil

1,318

769

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The loss of organic and inorganic carbon from roots into soil underpins nearly all the major changes that occur in the rhizosphere. In this review we explore the mechanistic basis of organic carbon and nitrogen flow in the rhizosphere. It is clear that C and N flow in the rhizosphere is extremely complex, being highly plant and environment dependent and varying both spatially and temporally along the root. Consequently, the amount and type of rhizodeposits (e.g. exudates, border cells, mucilage) remains highly context specific. This has severely limited our capacity to quantify and model the amount of rhizodeposition in ecosystem processes such as C sequestration and nutrient acquisition. It is now evident that C and N flow at the soil-root interface is bidirectional with C and N being lost from roots and taken up from the soil simultaneously. Here we present four alternative hypotheses to explain why high and low molecular weight organic compounds are actively cycled in the rhizosphere. These include:(1) indirect, fortuitous root exudate recapture as part of the root's C and N distribution network, (2) direct re-uptake to enhance the plant's C efficiency and to reduce rhizosphere microbial growth and pathogen attack, (3) direct uptake to recapture organic nutrients released from soil organic matter, and (4) for interroot and root-microbial signal exchange. Due to severe flaws in the interpretation of commonly used isotopic labelling techniques, there is still great uncertainty surrounding the importance of these individual fluxes in the rhizosphere. Due to the importance of rhizodeposition in regulating ecosystem functioning, it is critical that future research focuses on resolving the quantitative importance of the different C and N fluxes operating in the rhizosphere and the ways in which these vary spatially and temporally.

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Section: Carbon Flow To Mycorrhizal and Bacterial Symbiontsmentioning

confidence: 97%

Carbon flow in the rhizosphere: carbon trading at the soil–root interface

Jones

Nguyen²,

Finlay³

2009

Plant Soil

1,318

769

View full text Add to dashboard Cite

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“…It is also possible that any differences in % C assimilation may be exacerbated following N addition when some methane oxidisers may switch to oxidising ammonia, as C conversion efficiency may decrease after ammonia addition to soil (Roslev et al 1997). Secondly, rapid turnover of C in soil (Rangel-Castro et al 2005) means that 13 C-CO 2 production from heterotrophic activity as opposed to methane oxidation per se can not be discounted.…”

Section: Ch 4 Oxidation Rates In Response To N Applicationmentioning

confidence: 98%

Interactions between N application rate, CH4 oxidation and N2O production in soil

Acton

Baggs

2010

Biogeochemistry

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Here we report on a controlled environment experiment in which we applied 13 C-and 15 N-enrichment approaches to quantify methane oxidation rates and source partition N 2 O production in a silt loam soil following application of NH 4 NO 3 , enabling us to look for potential interactions between methane oxidation and nitrifier-N 2 O production. 15 N-N 2 O, 14?15 N-N 2 O and CO 2 fluxes and mineral N concentrations were measured over a 23-day period after application of NH 4 NO 3 (5 at.% excess 15 N) at rates of 0, 5, 10, 20, 30 and 40 g N m -2 to a silt loam soil. Change in 12/13 C-CH 4 concentrations (as indicative of 13 C-CH 4 oxidation rates) and production of 13 C-CO 2 were monitored over the first 72 h after addition of 1.7 ll 13 C-CH 4 l -1 (10 at.% excess 13 C) to these N treatments. Oxidation of applied 13 C-CH 4 was slower in the 5, 10, 20 and 30 g N m -2 (5 at.% excess 15 N) treatments (0.24-0.32 lg 13 C-CH 4 l -1 day -1 ) than in the control (0.40 lg 13 C-CH 4 l -1 day -1 ), suggesting that these N loadings inhibited oxidation. N 2 O production was raised after N addition, and in the 10, 20 and 30 g N m -2 treatments nitrification was the predominant source of N 2 O accounting for 61, 83 and 57% of the total 15 N-N 2 O produced, respectively. Our results point towards the possibility of methylotrophs switching function to oxidise ammonia in the presence of N, which may result in greater atmospheric loading of both CH 4 and N 2 O.

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“…Furthermore, the method can be run with up to three orders of magnitude less sample material compared to conventional methods for direct analyses of nucleic acids [Rangel-Castro et al, 2005] and can be used for both DNA-and RNA-based SIP studies. Another method development was described as CHIP-SIP where RNA-SIP, phylogenetic microarrays and nanoSIMS were combined to increase the sensitivity of 13 C and 15 N incorporation and to determine the phylogenetic identity of the 'heavy' cells.…”

Section: Methods Developments In Sip Techniquesmentioning

confidence: 99%

Stable Isotope Probing Approaches to Study Anaerobic Hydrocarbon Degradation and Degraders

et al. 2016

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Stable isotope probing (SIP) techniques have become state-of-the-art in microbial ecology over the last 10 years, allowing for the targeted detection and identification of organisms, metabolic pathways and elemental fluxes active in specific processes within complex microbial communities. For studying anaerobic hydrocarbon-degrading microbial communities, four stable isotope techniques have been used so far: DNA/RNA-SIP, PLFA (phospholipid-derived fatty acids)-SIP, protein-SIP, and single-cell-SIP by nanoSIMS (nanoscale secondary ion mass spectrometry) or confocal Raman microscopy. DNA/RNA-SIP techniques are most frequently applied due to their most meaningful phylogenetic resolution. Especially using ¹³C-labeled benzene and toluene as model substrates, many new hydrocarbon degraders have been identified by SIP under various electron acceptor conditions. This has extended the current perspective of the true diversity of anaerobic hydrocarbon degraders relevant in the environment. Syntrophic hydrocarbon degradation was found to be a common mechanism for various electron acceptors. Fundamental concepts and recent advances in SIP are reflected here. A discussion is presented concerning how these techniques generate direct insights into intrinsic hydrocarbon degrader populations in environmental systems and how useful they are for more integrated approaches in the monitoring of contaminated sites and for bioremediation.

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Flux and turnover of fixed carbon in soil microbial biomass of limed and unlimed plots of an upland grassland ecosystem

Cited by 33 publications

References 50 publications

Carbon flow in the rhizosphere: carbon trading at the soil–root interface

Carbon flow in the rhizosphere: carbon trading at the soil–root interface

Interactions between N application rate, CH4 oxidation and N2O production in soil

Stable Isotope Probing Approaches to Study Anaerobic Hydrocarbon Degradation and Degraders

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