The Tourbières observatory is a network of 4 instrumented peatlands located along a topographic (from 100 to 1,400 m) and anthropization gradient: La Guette and Landemarais in the plains with oceanic climate, Frasne at medium altitude in Jura and Bernadouze in the Pyrénées chain.
These peatlands are wetlands characterized by a particular moss, the sphagnum moss. It thrives at high rainfall, often low temperatures, and acidic and nutrient-poor water. Sphagnum mosses are ingenious species: by their morphological and chemical characteristics, they are able to promote the favorable conditions for their own development. These conditions limit biological decomposition so efficiently that organic matter accumulates and forms peat. These original and critical ecosystems are home to a unique biodiversity and play a crucial role in the carbon cycle. Despite a cover of 3% of the land surface, peatlands contain between 25% and 30% of the world’s soil carbon stock.
Starting year: 2008 at la Guette and Frasne, 2012 at Bernadouze, 2014 at Landemarais
Locations: Brittany, Drugeon valley, Vicdessos valley, Sologne
Keywords: wetlands, carbon footprint, climate change, greenhouse gases
The scientific questions of the Tourbières observatory are:
- What is the current carbon and hydrological balance of peatlands?
- What is the response of peatlands to climate change in terms of both processes and greenhouse gas fluxes?
The peatlands of the network provide strong constraints to feed global climate change space-for-time substitution models. One of the 4 sites, La Guette, has been accredited since 2019 as an associated site in the European research infrastructure for observing greenhouse gas flows: ICOS-Ecosystem (Integrated Carbon Observation System).
Sites and measured variables
The sites of the Tourbières are the following ones: la Guette peatland in Sologne (145 m, 26 ha, 11 °C average annual temperature, 880 mm/year rainfall, Sologne sands), the Landemarais peatland north of Fougères (154 m, 23 ha, 11 °C, 870, Cadomian granites), the peatland of Frasne near Pontarlier (830 m, 98 ha, 7.5 °C, 1,400 mm/year rainfall, Jurassic limestones and moraines), and the peatland of Bernadouze in Ariège (1,400 m, 3.8 ha, 6 °C, 1,700 mm/year rainfall, Hercynian granites and moraines).
The Tourbières instruments (ground meteorological stations, closed chambers and eddy covariance station, piezometers, multiparameter hydrological station) collect measurements common to the 4 sites, at different frequencies, from several times per second to once every 30 minutes. This instrumentation ensemble makes it possible to quantify evapotranspiration and heat fluxes (sensible and latent) and organic carbon concentrations at the outlet. The hydrological variables (flow rates, piezometric levels, meteorological data) and environmental data enables the establishment of ecosystem-scale carbon and hydrological balances. Greenhouse measurements were implemented according to the recommendations of the ICOS RI (Integrated Carbon Observation System).
The Tourbières observatory also hosts in situ experimental devices for simulating climate and anthropogenic forcing. The Tourbières sites also host national and European ecological restoration projects (regional projects, LIFE and INTERREG programs).
Partners and further information
Tourbières is an observation service labelled by the INSU-CNRS. It is led by the Observatoire des Sciences de l’Univers en région Centre (OSUC) and the Institut des Sciences de la Terre d’Orléans (ISTO) in collaboration with the Observatoire des Sciences de l’Univers Terre-Homme Environnement-Temps-Astronomie (OSU THETA), the Laboratoire Chrono-Environnement (Besançon), the Observatoire des Sciences de l’Univers de Rennes (OSUR), l’unité ECOBIO (Rennes), the Observatoire Homme-Milieu Pyrénées (OHM Haut-Vicdessos), the Laboratoire GÉODE and the Laboratoire ECOLAB (Toulouse). All the sites are integrated in a Zone Atelier (ZA) of the INEE (IR Réseau des Zones Ateliers): Frasne in ZA Arc Jurassien, Landemarais in ZA Armorique, la Guette ZA Loire and Bernadouze in ZA PyGar.