Tracking the flow of bacterially derived C-13 and N-15 through soil faunal feeding channels

F. V. Crotty*, R. P. Blackshaw, P. J. Murray

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

60 Citations (SciVal)

Abstract

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 C-13 and N-15, to trace the flow of bacterial C and N through the soil food web. Throughout the experiment the soil remained enriched in C-13 and N-15. 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 C-13 and N-15 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. Copyright (C) 2011 John Wiley & Sons, Ltd.

Original languageEnglish
Pages (from-to)1503-1513
Number of pages11
JournalRapid Communications in Mass Spectrometry
Volume25
Issue number11
DOIs
Publication statusPublished - 15 Jun 2011
EventCombined Meetings of the BMSS Special Interest Group on Stable Isotopes (BMSS ISO-SIG)/ Stable Isotopes Mass Spectrometry Users Group (SIMSUG)/ Stable Isotopes in Biosphere-Atmosphere-Earth System Research (SIBAE) - Exeter
Duration: 27 Apr 201030 Apr 2010

Keywords

  • STABLE-ISOTOPE ANALYSIS
  • COLLEMBOLA
  • RAIN-FOREST
  • TROPHIC STRUCTURE
  • NITROGEN MINERALIZATION
  • FOOD-WEB
  • BEECH FORESTS
  • MICROBIAL LOOP
  • NICHE DIFFERENTIATION
  • PLANT-GROWTH

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