ESR8: Development of methods to estimate rates, controlling factors and mechanisms of N cycling processes at different reactive interfaces


Research Fellow: Tim Vaessen, Agencia Estatal Consejo Superior de Investigaciones Científicas (Spain)


ESR8 will assess the role of reactive interfaces for N-cycling in stream-riparian ecosystems by developing field methods to quantify N processing rates and compare them among interfaces.

Tasks and methodology

This research will be based on the use of stable isotopes (such as 15N) both as natural abundance and as tracer injections in combination with hydrologic tracers and smart traces and standard chemical analytical methods. Progress of methods developed in ESR1+9, ESR3, and ESR10 will be implemented as complementary approaches to help linking N cycling with hydrological flow paths. These techniques will be combined with molecular biology techniques (in collaboration with ERS5+6) to link the biogeochemical processes with key microbial players within the biofilms of these interfaces (e.g., denitrifyers, ammonia + nitrite oxydizers) and their activities (exoenzimatic activities, Massive Parallel Amplicon Sequencing of ribosomal genes). These techniques will be complemented with techniques for C-metabolism (ESR4) to examine the coupling between the cycling of C and N at the different interfaces. Development of the techniques can include both whole-reach and habitat specific measurements.


  • Eugenia Marti (CSIC)
  • Co-Supervisor: Gilles Pinay (CNRS)

Video Introduction

Watch this short video of ESR8 Tim Vaessen introducing himself and talking about his Interfaces project:

ESR8 Tim Vaessen - Introduction