Application of Lipid Analysis to Understand Trophic Interactions in Soil

Rueß, Liliane; Schütz, Kirsten; Haubert, Dominique; Häggblom, Max M.; Kandeler, Ellen; Scheu, Stefan

doi:10.1890/04-1399

Cited by 88 publications

(105 citation statements)

References 43 publications

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“…In addition, L. terrestris contains other long-chain PLFAs, including 20:3?6 and 22:5?3 (Sampedro et al 2006), that were not detected in soils of this study and therefore our assumption is that these PLFAs are predominantly restricted to micro-and mesofauna such as protozoa, nematodes and Collembola. A limitation of the PLFA approach applied to soil fauna is that PLFAs associated with eukaryotes and animals in particular are non-specific and common across taxa (Ruess and Chamberlain 2010), but this has not hindered serious efforts to employ fatty acids to study soil food web structures and trophic interactions (Ruess et al 2002, Ruess et al 2005, Ruess and Chamberlain 2010. In this study, we avoided assigning animal PLFAs to specific taxa, but nevertheless, we were able to determine that the drilosphere environment can not only be defined by its greater biomass of heterogeneous microbial communities, but by the presence of greater concentrations of micro/mesofauna PLFAs that are not typical of bulk soils.…”

Section: Microbial and Faunal Communitiesmentioning

confidence: 99%

Distinct microbial and faunal communities and translocated carbon in Lumbricus terrestris drilospheres

Stromberger

Keith

Schmidt

2012

Soil Biology and Biochemistry

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Lumbricus terrestris is a deep-burrowing anecic earthworm that builds permanent, vertical burrows with linings (e.g. drilosphere) that are stable and long-lived microhabitats for bacteria, fungi, micro-and mesofauna. We conducted the first non-culture based field study to assess simultaneously the drilosphere (here sampled as 0-2 mm burrow lining) composition of microbial and micro/mesofaunal communities relative to bulk soil. Our study also included a treatment of surface-applied 13 C-and 15 N-labeled plant residue to trace the short-term (40 d) translocation of residue C and N into the drilosphere, and potentially the assimilation of residue C into drilosphere microbial phospholipid fatty acids (PLFAs). Total C concentration was 23%, microbial PLFA biomass was 58%, and PLFAs associated with protozoa, nematodes, Collembola and other fauna were 200-to-300% greater in the drilosphere than in nearby bulk soil. Principal components analysis of community PLFAs revealed that distributions of Gram-negative bacteria and actinomycetes and other Gram-positive bacteria were highly variable among drilosphere samples, and that drilosphere communities were distinct from bulk soil communities due to the atypical distribution of PLFA biomarkers for micro-and mesofauna. The degree of microbial PLFA 13 C enrichment in drilosphere soils receiving 13 C-labeled residue was highly variable, and only one PLFA, 18:1(9c, was significantly enriched. In contrast, 11 PLFAs from diverse microbial groups where enriched in response to residue amendment in bulk soil 0-5 cm deep. Among control soils, however, a significant ( 13 C shift between drilosphere and bulk soil at the same depth (5-15 cm) revealed the importance of L. terrestis for translocating perennial rye grass-derived C into the soil at depth, where we estimated the contribution of the recent grass C (8 years) to be at least 26% of the drilosphere soil C. We conclude that L. terrestris facilitates the translocation of plant C into soil at depth and promotes the maintenance of distinct soil microbial and faunal communities that are unlike those found in the bulk soil.

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Section: Microbial and Faunal Communitiesmentioning

confidence: 99%

Distinct microbial and faunal communities and translocated carbon in Lumbricus terrestris drilospheres

Stromberger

Keith

Schmidt

2012

Soil Biology and Biochemistry

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“…The qualitative nature of FA analysis, in particular, is limiting. Comparing the FA profile of animals fed a diet of known FA composition with that of individuals from the field could help determine their diet with more accuracy (Ruess et al 2005). Microcosm and field experiments using a range of isotopically labeled food sources (e.g.…”

mentioning

confidence: 99%

A multi-method approach for identifying meiofaunal trophic connections

Leduc¹,

Probert²,

Duncan³

2009

Mar. Ecol. Prog. Ser.

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Meiofauna can play an important role in the energetics of benthic communities, but determining their diet remains problematic due to their small size. In this study, the contribution of primary producers to the diet of meiofauna and to bulk and fine (<125 µ µm) sediment organic matter (SOM) was investigated in Papanui Inlet, southern New Zealand, using stable isotopes (δ 13 C and δ 15 N) and fatty acid analyses in the field and in a microcosm experiment. Seston did not contribute significantly to SOM of vegetated (seagrass Zostera muelleri) and unvegetated habitats, suggesting limited bentho-pelagic coupling. The contribution of different benthic primary producers to SOM and meiofaunal diet could not be determined accurately based on isotopic signatures alone due to overlapping isotopic signatures. The high content of highly unsaturated fatty acids (HUFAs) of harpacticoid copepods from vegetated and unvegetated sites suggested that their main food item was microphytobenthos (MPB), although bacterial biomarkers were twice as abundant in copepods sampled from the seagrass bed than in copepods sampled from unvegetated sediments. Isotopic and fatty acid analyses showed that the uptake of 13 C-labeled macroalgal (Enteromorpha sp.) detritus by harpacticoid copepods in the microcosm experiment was minimal. Nematode diet could not be assessed with certainty, but seagrass detritus and MPB are likely to represent significant food sources at the vegetated and unvegetated sites, respectively, based on the fatty-acid profile of fine SOM. This combined approach (i.e. isotopic and fatty acid analyses, field sampling and microcosms), and analysis of bulk SOM, fine SOM, and aged seagrass detritus helped circumvent limitations associated with the individual methods. The combination of approaches was still insufficient to quantify the contribution of different primary producers to meiofaunal diet, however, highlighting the difficulties associated with the study of meiofaunal trophic connections in coastal systems. KEY WORDS: Parastenhelia megarostrum · Feeding ecology · Intertidal Resale or republication not permitted without written consent of the publisherMar Ecol Prog Ser 383: [95][96][97][98][99][100][101][102][103][104][105][106][107][108][109][110][111] 2009 Vincx 1997). The use of stable isotopes as tracers of organic matter flows in benthic food webs has shed light on the diet of nematodes and harpacticoid copepods in a variety of shallow benthic habitats (e.g. Couch 1989, Middelburg et al. 2000, Moens et al. 2005. Few studies have determined the isotopic signature of nematodes and harpacticoid copepods in seagrass meadows (e.g. Vizzini & Mazzola 2003), which contrasts with the numerous stable isotope studies of macrofauna of seagrass beds (see review by Lepoint et al. 2004).Carbon stable isotopes can be particularly useful for the study of food webs of seagrass communities due to the often elevated δ 13 C signature of seagrass tissue relative to other primary producers (Hemminga & Mateo 1996). The difference ...

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“…Gas samples were collected and stored in evacuated 12 mL butyl septum-capped vials (Exetainer®, Labco Ltd., High Wycombe, UK) before analysis by mass spectrometry. Due to known storage effects on 13 C values, [32] the butyl septum caps were heated to 105°C for 12 h immediately prior to use, as this has been found to prevent changes in the 13 C signatures over time. [33] On each of the sampling days, the core was removed from the plastic sleeve and a vertical slice (approximately 150 g) of the core was removed and homogenised; this slice was taken from the centre of the core to the edge, and encompassed approximately 15% of its circumference.…”

Section: Samplingmentioning

confidence: 99%

“…[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%

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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Application of Lipid Analysis to Understand Trophic Interactions in Soil

Cited by 88 publications

References 43 publications

Distinct microbial and faunal communities and translocated carbon in Lumbricus terrestris drilospheres

Distinct microbial and faunal communities and translocated carbon in Lumbricus terrestris drilospheres

A multi-method approach for identifying meiofaunal trophic connections

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

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Application of Lipid Analysis to Understand Trophic Interactions in Soil

Cited by 88 publications

References 43 publications

Distinct microbial and faunal communities and translocated carbon in Lumbricus terrestris drilospheres

Distinct microbial and faunal communities and translocated carbon in Lumbricus terrestris drilospheres

A multi-method approach for identifying meiofaunal trophic connections

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

Contact Info

Product

Resources

About

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