Periodic Reporting for period 2 - GLOBALECOEVO (Integrating Microbial Evolution into Biogeochemical Models to Predict Soil Response to Drought)
Reporting period: 2022-06-01 to 2023-05-31
Problem addressed and relevance for society:
Soil carbon emissions are susceptible to climate change but can be reduced with new land management practices, provided soil carbon–climate feedback outcomes can be predicted. However, predictions from current large-scale soil carbon models differ greatly and reveal large uncertainties in the processes involved. One uncertainty is the effect of change in precipitation regimes on soil organic matter decomposition mediated by soil microorganisms. The EU-funded GLOBALECOEVO project aims to integrate variable decomposition–moisture functions into a large-scale soil carbon model to reflect precipitation history and carbon substrate influence on microbial responses to changes in soil moisture. The model used to calculate these functions will account for both ecological and evolutionary processes. The project will shed further light on soil response to climate change.
Objectives:
Soil is both the largest sink and source of organic carbon (C) exchanged with the atmosphere. These exchanges result from biological processes, the primary source being the decomposition of soil organic matter (SOM), which is controlled by physical factors such as climate. As such, soil C emissions are very vulnerable to climate change but can also be reduced with new land management practices if we can predict the outcomes of soil carbon-climate feedbacks. However, predictions from the existing large-scale soil C models strongly diverge, and reveal large uncertainties in the processes and controls at play. One of these uncertainties is the effect of change in precipitation regimes on SOM decomposition mediated by soil microorganisms. Functions describing the decomposition response of soil carbon to soil moisture are static in current large-scale models, yet recent empirical studies show that decay responses under new soil moisture conditions can change due to shifts in microbial communities. Recent evidence suggests that evolution is a key processes driving these shifts in microbial communities.
This project proposes to integrate variable decomposition-moisture functions into a large-scale soil C model to reflect precipitation history and carbon substrate influence on microbial responses to changing soil moisture. These functions will be calculated from a mechanistic microbial model that accounts for both ecological and evolutionary processes. The mechanistic model will be an updated version of the trait-based model DEMENT developed by the fellow’s supervisor at the partner institution (UC Irvine). The moisture response functions will be integrated into a commonly used soil carbon model, RothC, that has been incorporated into the global land surface model (ORCHIDEE) of the host institution (LSCE).
Soil carbon emissions are susceptible to climate change but can be reduced with new land management practices, provided soil carbon–climate feedback outcomes can be predicted. However, predictions from current large-scale soil carbon models differ greatly and reveal large uncertainties in the processes involved. One uncertainty is the effect of change in precipitation regimes on soil organic matter decomposition mediated by soil microorganisms. The EU-funded GLOBALECOEVO project aims to integrate variable decomposition–moisture functions into a large-scale soil carbon model to reflect precipitation history and carbon substrate influence on microbial responses to changes in soil moisture. The model used to calculate these functions will account for both ecological and evolutionary processes. The project will shed further light on soil response to climate change.
Objectives:
Soil is both the largest sink and source of organic carbon (C) exchanged with the atmosphere. These exchanges result from biological processes, the primary source being the decomposition of soil organic matter (SOM), which is controlled by physical factors such as climate. As such, soil C emissions are very vulnerable to climate change but can also be reduced with new land management practices if we can predict the outcomes of soil carbon-climate feedbacks. However, predictions from the existing large-scale soil C models strongly diverge, and reveal large uncertainties in the processes and controls at play. One of these uncertainties is the effect of change in precipitation regimes on SOM decomposition mediated by soil microorganisms. Functions describing the decomposition response of soil carbon to soil moisture are static in current large-scale models, yet recent empirical studies show that decay responses under new soil moisture conditions can change due to shifts in microbial communities. Recent evidence suggests that evolution is a key processes driving these shifts in microbial communities.
This project proposes to integrate variable decomposition-moisture functions into a large-scale soil C model to reflect precipitation history and carbon substrate influence on microbial responses to changing soil moisture. These functions will be calculated from a mechanistic microbial model that accounts for both ecological and evolutionary processes. The mechanistic model will be an updated version of the trait-based model DEMENT developed by the fellow’s supervisor at the partner institution (UC Irvine). The moisture response functions will be integrated into a commonly used soil carbon model, RothC, that has been incorporated into the global land surface model (ORCHIDEE) of the host institution (LSCE).
Overall, the objectives and deliverables for
- WP1 has been completed
- WP2 has been mostly completed
The first goal of work package 1 was for the MSCA Fellow (Dr Elsa Abs, pronoun they/them) to familiarize themselves with the microbial process model (original version developed by Steve Allison in 2012), and to modify it to incorporate microbial eco-evolutionary responses to global change factors. This goal was achieved through a first project (the “invasion project”) that represented evolution as invasion of the community by individuals with new trait values, and that looked at how that modified the community response to global change.
The MSCA Fellow found that legacy effects were evident with substrate change for native communities differing in composition. Our simulations demonstrate that substrate quality changes associated with global change can lead to legacy effects on substrate degradation, but that such legacy effects occur if substrate inputs shift to higher protein content and if invasion is low.
The second goal of work package 1 was to identify whether the process of microbial response to environmental change matters to predict the change in soil C decay. Microbiomes can adapt to new conditions through different processes.
The MSCA found that mutation leads to higher adaptation to new substrate chemistry compared to local dispersal, but that there is no difference between the two adaptive processes when dispersal is regional. This is the consequence of taxa going extinct in the dispersal treatment and never being recovered, while the mutation treatment leads to slower response but allows, given enough time, to reach the same community composition as the microbiomes native to the new litter.
The goal of the work package 2 was to insert the microbial response functions to substrate change in a land model (ORCHIDEE), in order to identify the set of environmental conditions in which microbial evolution matters to accurately predict future soil C stocks. The MSCA Fellow has already proven that the model with microbial adaptation (DEMENTmut) gives predictions closer to the data from a large litter decay experiment than the microbial model MIMICS that is currently coupled with ORCHIDEE. They also estimated using 200 outputs from DEMENT a function to litter chemistry to replace the corresponding constant trait in MIMICS to capture microbial adaptation. They are running simulations of the new version of ORCHIDEE-MIMICS to find regions where microbial adaptation modifies SOC predictions when coupled with vegetation.
- WP1 has been completed
- WP2 has been mostly completed
The first goal of work package 1 was for the MSCA Fellow (Dr Elsa Abs, pronoun they/them) to familiarize themselves with the microbial process model (original version developed by Steve Allison in 2012), and to modify it to incorporate microbial eco-evolutionary responses to global change factors. This goal was achieved through a first project (the “invasion project”) that represented evolution as invasion of the community by individuals with new trait values, and that looked at how that modified the community response to global change.
The MSCA Fellow found that legacy effects were evident with substrate change for native communities differing in composition. Our simulations demonstrate that substrate quality changes associated with global change can lead to legacy effects on substrate degradation, but that such legacy effects occur if substrate inputs shift to higher protein content and if invasion is low.
The second goal of work package 1 was to identify whether the process of microbial response to environmental change matters to predict the change in soil C decay. Microbiomes can adapt to new conditions through different processes.
The MSCA found that mutation leads to higher adaptation to new substrate chemistry compared to local dispersal, but that there is no difference between the two adaptive processes when dispersal is regional. This is the consequence of taxa going extinct in the dispersal treatment and never being recovered, while the mutation treatment leads to slower response but allows, given enough time, to reach the same community composition as the microbiomes native to the new litter.
The goal of the work package 2 was to insert the microbial response functions to substrate change in a land model (ORCHIDEE), in order to identify the set of environmental conditions in which microbial evolution matters to accurately predict future soil C stocks. The MSCA Fellow has already proven that the model with microbial adaptation (DEMENTmut) gives predictions closer to the data from a large litter decay experiment than the microbial model MIMICS that is currently coupled with ORCHIDEE. They also estimated using 200 outputs from DEMENT a function to litter chemistry to replace the corresponding constant trait in MIMICS to capture microbial adaptation. They are running simulations of the new version of ORCHIDEE-MIMICS to find regions where microbial adaptation modifies SOC predictions when coupled with vegetation.
The impact of the MSCA fellowship remains on track at the organizational level. A strong
collaboration has been developed between the MSCA Fellow and colleagues at UC Irvine in California and at the Laboratory of Climate and Environmental Sciences in Paris. As stated at the outset, the generation of intellectual property from work conducted during the fellowship is unlikely. Given the successes and opportunities discussed above, the fellowship is on track to continue to promote gender balance and equality; positively contributing to the growth rate of female researchers in leadership roles within the ecology/microbiology/biogeochemistry and higher education sectors (in line with EU Gender Equality policy in public research).
The impact of the MSCA Fellowship at the system level is already higher than anticipated. The MSCA Fellow contributed to work on microbial response to environmental change (showing that microbial response to drought might increase the soil C losses predicted by current soil models) published in Trends in microbiology that led to a press release in the French newspaper Le Monde on May 2 2023.
collaboration has been developed between the MSCA Fellow and colleagues at UC Irvine in California and at the Laboratory of Climate and Environmental Sciences in Paris. As stated at the outset, the generation of intellectual property from work conducted during the fellowship is unlikely. Given the successes and opportunities discussed above, the fellowship is on track to continue to promote gender balance and equality; positively contributing to the growth rate of female researchers in leadership roles within the ecology/microbiology/biogeochemistry and higher education sectors (in line with EU Gender Equality policy in public research).
The impact of the MSCA Fellowship at the system level is already higher than anticipated. The MSCA Fellow contributed to work on microbial response to environmental change (showing that microbial response to drought might increase the soil C losses predicted by current soil models) published in Trends in microbiology that led to a press release in the French newspaper Le Monde on May 2 2023.