Impact of climate on soil respiration and net ecosystem exchange in temperate forests

Started in october 2023

Supervisors: Philippe Amiotte-Suchet, Julien Crétat et Olivier Mathieu

Funding: French national research agency (ANR)

Abstract

The impact of climate change on the biogeochemical carbon cycle is a major issue, especially its effects on carbon dioxide exchanges between the atmosphere and soils. Forest soils are of particular interest since they are the main reservoir of organic carbon in the lithosphere. Currently, there is no consensus about the impact of climate on soil respiration. In addition, the fertilizing effect of atmospheric carbon dioxide on photosynthesis may be canceled out by hydric stress induced by more and more frequent and long-lasting meteorological droughts. Furthermore, the impact of climate is modulated by tree species, forest management and soil pedological properties. The objectives of this project are to estimate the multi-scale climate impacts, including the water balance, both on the net ecosystem exchange (NEE) over forests and on soil respiration. Two emblematic sites of the Bourgogne Franche-Comté region have been selected: the Morvan, a semi-mountainous territory strongly impacted by climate change, and the National Forest Park located in the plain and instrumented since 2020 to measure soil respiration. To answer, re-analysed, dynamically disaggregated and measured climate data will be used to feed a forest water balance model and to derive intra-seasonal indicators of climate variability. These quantities will be compared with the monthly NEE in order to estimate the synchronous and lagged covariations at the interannual scale. Similar analyses will be done for soil respiration at both the monthly and daily timescales. These analyses will be carried out with and without taking into account tree species, forest management and soil pedological properties with the aim of prioritising the determinants of NEE and soil respiration fluctuations. Other sites from the COSORE meta-analysis will be used to validate the results and replicate the approach.

Keywords

climate ; soil respiration ; NEE ; forest

extrait:

lien_externe:

titre:

Impact du climat sur la respiration des sols et l’échange net de carbone de l'écosystème en milieu forestier tempéré

date_de_debut_these:

octobre 2023

nom:

Capelle

date_de_debut_these_numerique:

20231002

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kc_raw_content:

Impact of climate on soil respiration and net ecosystem exchange in temperate forests

Started in october 2023

Supervisors: Philippe Amiotte-Suchet, Julien Crétat et Olivier Mathieu

Funding: French national research agency (ANR)

 

Abstract

The impact of climate change on the biogeochemical carbon cycle is a major issue, especially its effects on carbon dioxide exchanges between the atmosphere and soils. Forest soils are of particular interest since they are the main reservoir of organic carbon in the lithosphere. Currently, there is no consensus about the impact of climate on soil respiration. In addition, the fertilizing effect of atmospheric carbon dioxide on photosynthesis may be canceled out by hydric stress induced by more and more frequent and long-lasting meteorological droughts. Furthermore, the impact of climate is modulated by tree species, forest management and soil pedological properties. The objectives of this project are to estimate the multi-scale climate impacts, including the water balance, both on the net ecosystem exchange (NEE) over forests and on soil respiration. Two emblematic sites of the Bourgogne Franche-Comté region have been selected: the Morvan, a semi-mountainous territory strongly impacted by climate change, and the National Forest Park located in the plain and instrumented since 2020 to measure soil respiration. To answer, re-analysed, dynamically disaggregated and measured climate data will be used to feed a forest water balance model and to derive intra-seasonal indicators of climate variability. These quantities will be compared with the monthly NEE in order to estimate the synchronous and lagged covariations at the interannual scale. Similar analyses will be done for soil respiration at both the monthly and daily timescales. These analyses will be carried out with and without taking into account tree species, forest management and soil pedological properties with the aim of prioritising the determinants of NEE and soil respiration fluctuations. Other sites from the COSORE meta-analysis will be used to validate the results and replicate the approach.

 

Keywords

climate ; soil respiration ; NEE ; forest