Climate control of terrestrial carbon exchange across biomes and continents

in Environmental Research Letters (2010), 5(3),

Understanding the relationships between climate and carbon exchange by terrestrial ecosystems is critical to predict future levels of atmospheric carbon dioxide because of the potential accelerating ... [more ▼]

Understanding the relationships between climate and carbon exchange by terrestrial ecosystems is critical to predict future levels of atmospheric carbon dioxide because of the potential accelerating effects of positive climate-carbon cycle feedbacks. However, directly observed relationships between climate and terrestrial CO2 exchange with the atmosphere across biomes and continents are lacking. Here we present data describing the relationships between net ecosystem exchange of carbon (NEE) and climate factors as measured using the eddy covariance method at 125 unique sites in various ecosystems over six continents with a total of 559 site-years. We find that NEE observed at eddy covariance sites is (1) a strong function of mean annual temperature at mid-and high-latitudes, (2) a strong function of dryness at mid-and low-latitudes, and (3) a function of both temperature and dryness around the mid-latitudinal belt (45 degrees N). The sensitivity of NEE to mean annual temperature breaks down at similar to 16 degrees C (a threshold value of mean annual temperature), above which no further increase of CO2 uptake with temperature was observed and dryness influence overrules temperature influence. [less ▲]

Management effects on European cropland respiration

in Agriculture, Ecosystems & Environment (2010), 139

The net biome production of full crop rotations in Europe

in Agriculture, Ecosystems & Environment (2010), 139

Carbon Balance Of A Crop Rotation Cycle: Overview Of A 4 Year Investigation

Conference (2009, September)

Interannual variability of CO2 fluxes, growth and yield by a winter wheat crop (Triticum aestivum L.)

Poster (2009, April 02)

Les grandes cultures et le CO2

in Livre Blanc Céréales (2009, February 18)

Impact of climatic conditions on a winter wheat (Triticum aestivum Sp.) crop : interannual variability of CO2 fluxes, plant growth and crop yield

Poster (2008, September)

This study analyses the interannual variability of carbon dioxide fluxes, growth and productivity of a winter wheat (Triticum aestivum L.) crop. Two growing seasons (2004-2005 and 2006-2007) were compared ... [more ▼]

This study analyses the interannual variability of carbon dioxide fluxes, growth and productivity of a winter wheat (Triticum aestivum L.) crop. Two growing seasons (2004-2005 and 2006-2007) were compared. Continuous eddy covariance fluxes, leaf scale photosynthesis measurements and crop development monitoring were performed during the two vegetation seasons until harvest at the Lonzée (Belgium) experimental site. The winter wheat was sown and harvested at similar dates (about mid-October and in early August); crop management by the farmer was similar and corresponded at standard. Globally, the two years were characterised by a higher than normal air temperature (9.9 °C and 11.9 °C against 9.4 °C) and lower than normal rainfalls (595.1 mm and 675.1 mm against 772 mm). In addition, 2006-2007 was characterised by exceptionally mild and dry winter and spring. This induced not only earlier growth stages but also a larger Gross Primary Productivity. On the contrary, lower Net Primary Productivity and crop productivity were observed on this year. This could be explained, on one hand by the drought in April 2007 and on the other hand to cloudy and humid conditions from end May to harvest. The first induced a stress in wheat plant which produced an unusually small flag leaf. The second induced an assimilation reduction due to low radiation and favoured disease development. The higher GPP and the lower productivity in 2006-2007 raise the question of carbon allocation. We supposed that, as the excess of carbon assimilated in 2006-2007 was not stored in grain or straw, it should have been stored in the roots. However, our biomass measurements did not allow confirming this hypothesis [less ▲]

Description of cropland CO2 exchange : a comparison of empirical and physiologically based estimates of Reco, GPP and NEE

in CarboEurope-IP meeting 2008 (2008)

Mesure des flux de CO2 et bilan carboné de grandes cultures : Etat de la question et méthodologie

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (2008), 12(3), 303-315

Nos grandes cultures captent aussi le CO2

in Nouvelles du Printemps (Les) (2007), (2ème trimestre 2007), 30-31