Continental carbon cycle: Sources, sinks, transport and anthropogenic disturbances

Dominique SERÇA
05 61 33 27 04

Frédéric GUÉRIN
05 61 33 26 66

carbon cycle • watershed • aquatic ecosystems • anthropogenic perturbations or land use change • carbon sequestration • field work and measurements

Learning objectives

The route of carbon will be followed at the watershed scale from the atmosphere to the ocean through the consumption of atmospheric CO2 by the vegetation, its transfer to the soil through soil organic matter (litter, roots and microbial biomass) in which carbon is incorporated and its export to the ocean after being transported and processed in aquatic ecosystems. In each compartment of the critical zone (soil, groundwater, surface waters, sediments, atmosphere), organic and inorganic carbon undergo transformations via microbiological activity and change in physico-chemical conditions that lead to partial sequestration (precipitation, sedimentation) and greenhouse gas- GHG emissions (carbon dioxide, methane). The impact of anthropogenic perturbation will be illustrated by the modification of the carbon cycle after the impoundment of a hydroelectric reservoir (land-use change).

This course mainly focuses on field methods with relevance to research studies on different aspects of continental carbon cycle. Students will have access to a set of relevant tools applied in fundamental research to approach environmental issues dealing with carbon biogeochemistry in atmosphere, surface water, groundwater, soil and sediments. Students will learn to properly collect and analyze samples, process and validate data with the help of different methods. They will also learn to combine theoretical, methodological and naturalist approaches to gain both in qualitative and quantitative expertise considering the terrestrial carbon cycle and the associated biogeochemical processes.


  • Aquatic chemistry
  • Global carbon cycle
  • Soil forming processes and pedogenesis
  • Acid-base equilibrium

Brief description of the course

  • Global carbon cycle/carbon cycle in rivers, lakes and wetlands/carbon cycle in hydroelectric reservoirs
  • Introduction to early diagenesis processes (bacteria-mediated redox reactions)
  • Carbon cycle and the soil compartment – observations and theories
  • Carbon and GHG analytical techniques, GHG flux metrology
  • Climate change/overview of carbonate systems/CO2 sequestration/CO2 (bio)mineralization
  • Use of natural radionuclides (U, Th series) as geochemical tracers to study processes and quantify chemical fluxes and as chronometers to estimate the time-scale of these processes

The lectures will be complemented by fieldwork (sampling and in situ measurements) and lab work (experimentation and measurements).