13C and 15N as Tracers in Soil Nutrient Studies
 
 
 

Carbon stable isotope values and feeding preferences


Stable isotope techniques at natural abundance level are a powerful tool in soil animal ecology because they offer a mean of studying undisturbed communities in different compartments of the soil system in situ.

Most studies have focused on dietary preferences of selected groups of soil animals.

13C

15N

12C
14N

 
 

  • Collembola are one of the most abundant and widespread groups of soil arthropods, yet investigation of their natural diet is problematic due to their small size and their opaque environment
  • The analysis of the isotope composition is considerably less time consuming than traditional observational and gut content analysis

 

 

d13C composition of F. candida feeding on yeast, soil, C4 litter and in soil plus C4 litter and their feeds (yeast, C3 soil and C4 litter)

Briones M.J.I., Ineson P. & Sleep D. (1999a). Use of d13C to determine food selection in collembolan species. Soil Biology & Bichemistry 31: 937-940.

C and N isotope values in agricultural systems
Maize plots at Neiro, Santiago (Spain)

 

 






  • Effects on nutrient dynamics
  • Effects on trophic structures
  • Effects on trace gas emission



d15N values of the different earthworms ecological categories


Earthworm trophic groups
EPIGEIC = surface dwellers
  
ANECIC= vertical burrows
 
ENDOGEIC = Deep burrowers
Briones M.J.I., Bol. R. Sleep D., Sampedro L. & Allen D. (1999b). A dynamic study of earthworm feeding ecology using stable isotopes. Rapid Communications in Mass Spectrometry 13: 1300-1304.

Briones M.J.I., Bol R., Sleep D. & Sampedro L. (1999c). Isotopic ecology of earthworms under grassland and arable cropping systems Pedobiologia 43: 675-683.

Briones M.J.I., Bol R., Sleep D., Allen D. & Sampedro L. (2001). Spatio-temporal variation of stable isotope ratios in earthworms under grassland and maize cropping systems. Soil Biology & Biochemistry 33: 1673-1682.

Briones M.J.I. & Bol R. (2003). Natural abundance of 13C and 15N in earthworms from different cropping treatments. Pedobiologia 47: 560-567.

Briones M.J.I. & Schmidt O. (2004). Stable isotope techniques in studies of the ecological diversity and functions of earthworm communities in agricultural soils. Recent Research Developments in Crop Science 1: 11-26.

13CO2 pulse labelling and in situ tracer experiments
CEH Stable Isotope Delivery Laboratory (SID)
Although enchytraeids are the most important group in terms of biomass, collembola and mites have a more important role in processing rizhosphere carbon


The Stable Isotope Delivery system administers a controlled flow of 13C labelled CO2 at ambient concentrations (~350 ppm) to 12 independent labelling chambers
13CO2 pulse chambers
 Ostle N., Briones M.J.I., Ineson P., Cole L., Staddon P. & Sleep D. (in prep.). Isotopic detection of recent photosynthate carbon flow into grassland rhizosphere fauna.