Stable isotopes and changing paradigms on soil nitrogen and carbon biogeochemistry

Abstract

Carreira, J.A., Viñegla, B., Blanes, M.C., García-Ruíz, R. (2010). Stable isotopes and changing paradigms on soil nitrogen and carbon biogeochemistry. Ecosistemas 19(3):14-23

Many perceptions on ecosystem biogeochemistry are based on flow diagrams in which element pools (boxes) are interconnected by abiotic and biotic mechanisms controlling transformations of chemical species and flows among the pools (arrows). Because of the ability of stable isotopes to integrate such processes over time and space, they have played a central role in our current understanding of nutrient cycling, particularly in the cases of N and C. Most fluxes and transformations involved in terrestrial nutrient cycling cross over or take place in soil compartments. We here review the development of new paradigms in soil nitrogen (and carbon) cycling research, to which stables isotopes contributed  through  three  main  approaches:  (i)  as  integrators  of  nutrient input/output  budgets  from  broad  ecosystems  compartments  or "black-boxes", (ii) as tracers to unravel specific processes and end-member pools operating within these black boxes, and (iii) as markers or indicators of nutrient use, availability and deficiency to plants. New challenges and future perspective to that respect are also discussed.