Dissipation of bacterially derived C and N through the meso- and macrofauna of a grassland soil

Murray, P. J.; Clegg, C. D.; Crotty, Felicity; Martinez, N. de la Fuente; Williams, J. K.; Blackshaw, R. P.

doi:10.1016/j.soilbio.2009.02.021

Cited by 39 publications

(34 citation statements)

References 27 publications

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“…[7] It has also been seen that there is significant fractionation of 13 C and 15 N in fungal hyphae, with isotopic levels differing between species [8,9] and within the same species, [10,11] including isotopic differences between different parts of the same organism. [12] Many studies utilise enrichment of stable isotopes as tracers to determine the trophic interactions occurring within soil food webs [13][14][15][16] and methods have been developed to enrich bacteria, [17] earthworms, [18] slugs, [19] and plant litter [20] to trace the passage of 13 C and 15 N through soil ecosystems. To date, there have been no studies investigating the enrichment of soil saprophytic fungi as tracers, to attempt to see the interactions occurring within the soil food web, although this approach was suggested by Hobbie [21] for extraradical ectomycorrhiza.…”

Section: Andmentioning

confidence: 99%

Differential growth of the fungus Absidia cylindrospora on ¹³C/¹⁵N‐labelled media

Crotty

Blackshaw

Murray

2011

Rapid Comm Mass Spectrometry

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Many studies utilise enrichment of stable isotopes as tracers to follow the interactions occurring within soil food webs and methods have been developed to enrich bacteria, soil fauna and plant litter, Here for the first time we attempt to enrich a soil fungus to 99 atom% with (13)C and (15)N stable isotopes. In this study our objectives were to (a) assess whether the saprotrophic zygomycete fungus Absidia cylindrospora could grow on a medium enriched to 99 atom% with (13)C-glucose and (15)N-ammonium chloride, (b) to determine the level of enrichment obtained, and (c) to examine the change in growth rate of this fungus while it was growing on the dually enriched medium. To achieve this, the fungus was grown on agar enriched with (13)C and (15)N to 99 atom% and its growth rate monitored. The results showed that A. cylindrospora would grow on the highly labelled growth medium, but that its rate of growth was affected compared with the rate on either natural abundance media or media highly enriched with a single isotope ((13)C or (15)N). The implications of these results is that although the fungus is able to utilise these heavier isotopes, the biochemical processes involved in growth are affected, and consideration should be given to these differences when using stable isotope tracers in, for example, soil food web studies.

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Section: Andmentioning

confidence: 99%

Differential growth of the fungus Absidia cylindrospora on ¹³C/¹⁵N‐labelled media

Crotty

Blackshaw

Murray

2011

Rapid Comm Mass Spectrometry

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“…Many studies have utilised enrichment with 13 C and 15 N stable isotopes as tracers to elucidate the interactions occurring within soil food webs [18,34,38,40,44]. Methods have been developed to enrich bacteria [38], fungi [12], earthworms [16], slugs [22] and plant litter [48], to trace the passage of 13 C and 15 N through soil ecosystems and act as an isotopic baseline [49].…”

Section: Introductionmentioning

confidence: 99%

“…Methods have been developed to enrich bacteria [38], fungi [12], earthworms [16], slugs [22] and plant litter [48], to trace the passage of 13 C and 15 N through soil ecosystems and act as an isotopic baseline [49]. Our aim of this study was to extend the methods developed to determine the uptake of bacterially derived C and N into the soil food web [13,38], using protozoa. Here, for the first time, we can report the use of stable isotopes to identify the trophic utilisation of indigenous protozoa and trace linkages within the soil food web.…”

Section: Introductionmentioning

confidence: 99%

Protozoan Pulses Unveil Their Pivotal Position Within the Soil Food Web

et al. 2011

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Protozoa are one of the most abundant groups of bacterivores within the soil and are responsible for mineralisation of bacterial biomass, having a large impact on C and N cycling. Little is known of their contribution to soil nutrient transfers or the identity of their consumers. Here, for the first time indigenous flagellates and ciliates, enriched to 83 atom% for (13)C and 10 atom% for (15)N, were introduced to soil cores from two different land managements, grassland and woodland with the same soil type, to trace the flow of protozoan C and N through the soil food web. Nematodes, Collembola, earthworms and insect larvae obtained the greatest amounts of C and N of protozoan origin, either through direct consumption or uptake of biomass post-cell death. Our results show that changes in management, affect the functioning of the soil food web and the utilisation of protozoa as a food source.

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“…[21] Addition of a substrate with a distinct isotopic signature can be used as an isotopic fingerprint in newly synthesised faunal compounds. [22] Methods have been developed to enrich bacteria, [23] earthworms, [24] slugs, [25] plant litter, [26] and the growing plant, [27] to trace the passage of 13 C and 15 N through soil ecosystems. Most of these studies focus on the origin of C compounds -whether they have been obtained from the rhizosphere or decomposing plant material, e.g.…”

mentioning

confidence: 99%

“…[22,28] but are unable to ascertain whether an intermediary microbial step is involved. [29] In order to investigate the flow of C and N from the microbial step upwards, Murray et al [23] introduced an enriched bacterium and added this to grassland soil managed with two different nutrient regimes. Here we track the flow of C and N through the soil food web through the addition of a highly enriched native bacterium -Pseudomonas lurida, introduced to soil cores from two different habitat managements, a grassland and a woodland with the same basal soil type, both of which 20 years ago were managed grassland.…”

mentioning

confidence: 99%

Tracking the flow of bacterially derived¹³C and¹⁵N through soil faunal feeding channels

Crotty

Blackshaw

Murray

2011

Rapid Comm Mass Spectrometry

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The soil food web has been referred to as a 'black box', a 'poor man's tropical rainforest' and an 'enigma', due to its opacity, diversity and the limited insight into feeding specificity. Here we investigate the flow of C and N through the soil food web as a way to gain understanding of the feeding interactions occurring. A bacterium, Pseudomonas lurida, was introduced to soil cores from two different habitats, a grassland and a woodland with the same soil type, enriched to 99 atom% in (13)C and (15)N, to trace the flow of bacterial C and N through the soil food web. Throughout the experiment the soil remained enriched in (13)C and (15)N. Almost all the invertebrates tested gained C and N enrichment indicative of the labelled bacteria, implying that bacterial feeding is a common mechanism within the soil. Only three groups were significantly enriched in both (13)C and (15)N in both habitats. These were Collembola (Entomobryomorpha), Acari (Oribatida), and Nematoda, indicating that these organisms are consuming the most bacteria within both systems. When the invertebrates were grouped into hypothesised trophic levels, those considered secondary decomposers were gaining the most enrichment across all invertebrates tested. This enrichment was also high in the micro-predators within the soil, implying that their main food source was the secondary decomposers, particularly the Collembola. Using an enriched bacterium to track the trophic transfer between organisms within the soil food web is a novel way of empirically showing that interactions are occurring, which normally cannot be seen.

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Dissipation of bacterially derived C and N through the meso- and macrofauna of a grassland soil

Cited by 39 publications

References 27 publications

Differential growth of the fungus Absidia cylindrospora on ¹³C/¹⁵N‐labelled media

Differential growth of the fungus Absidia cylindrospora on ¹³C/¹⁵N‐labelled media

Protozoan Pulses Unveil Their Pivotal Position Within the Soil Food Web

Tracking the flow of bacterially derived¹³C and¹⁵N through soil faunal feeding channels

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Dissipation of bacterially derived C and N through the meso- and macrofauna of a grassland soil

Cited by 39 publications

References 27 publications

Differential growth of the fungus Absidia cylindrospora on 13C/15N‐labelled media

Differential growth of the fungus Absidia cylindrospora on 13C/15N‐labelled media

Protozoan Pulses Unveil Their Pivotal Position Within the Soil Food Web

Tracking the flow of bacterially derived13C and15N through soil faunal feeding channels

Contact Info

Product

Resources

About

Differential growth of the fungus Absidia cylindrospora on ¹³C/¹⁵N‐labelled media

Differential growth of the fungus Absidia cylindrospora on ¹³C/¹⁵N‐labelled media

Tracking the flow of bacterially derived¹³C and¹⁵N through soil faunal feeding channels