Microbial Evolution – An Under-Appreciated Driver of Soil Carbon Cycling

Posted by Design Studio

26 June 2024

Challenge 2: Soil Carbon


Microbial evolution is a crucial yet often overlooked factor in soil carbon cycling and its interaction with climate change. While significant progress has been made in understanding ecological impacts, the evolutionary aspects have not been thoroughly integrated into biogeochemical models. This article examines the role of microbial evolution in soil carbon dynamics and proposes a comprehensive roadmap for incorporating these processes into predictive models.


Microbial Evolution and Carbon Cycling 

Microbes are the primary agents of carbon cycling in soils, capable of evolving rapidly in response to environmental changes. This evolution can significantly alter carbon-climate feedbacks. Microbial adaptations influence soil carbon dynamics, affecting carbon storage and CO2 emissions. As microbes adapt to changing conditions, they can alter soil structure, nutrient exchange with plants, and overall soil carbon processes.


Current Understanding and Conceptual Framework

The traditional divide between ecology and evolution is less relevant for microbes due to their simultaneous ecological and evolutionary responses to environmental changes. Microbial evolution occurs at similar timescales to ecological processes, making it essential to consider both historical and contemporary evolutionary processes. Historical evolution shapes the current genetic diversity and functional traits, while contemporary evolution represents ongoing adaptations to environmental changes.


Impact of Microbial Evolution in Laboratory and Field Studies 

Laboratory studies have demonstrated rapid microbial evolution under controlled conditions, such as changes in substrate use and temperature adaptation. However, these findings can be challenging to extrapolate to natural environments due to simplified conditions. Field studies show that ecological interactions and environmental heterogeneity significantly influence microbial evolution and its impact on carbon cycling.


Roadmap for Integrating Microbial Evolution into Models 

To integrate microbial evolution into biogeochemical models, a multi-scale approach is proposed:

  1. Microscale Mechanistic Models: Develop models to predict evolutionary responses based on environmental parameters and microbial traits.
  2. Omics Data Validation: Use genomic, transcriptomic, proteomic, and metabolomic data to validate model predictions and understand microbial functional traits.
  3. Scaling Up: Extend microscale models to ecosystem and global scales, incorporating microbial-vegetation-climate feedbacks.

Implementing this roadmap will require significant scientific investment and collaboration over the next 10 to 20 years.



Understanding and modeling microbial evolution is critical for accurate predictions of soil carbon dynamics under changing environmental conditions. This integration will provide a more comprehensive understanding of the role of microbes in biogeochemistry and their impact on global carbon cycling in the context of climate change.


Conceptual framework of the integration of microbial evolution into ecosystem models across levels of biological organization (left) and spatial scales (right). In red are the data that can be used to calibrate or validate models at different scales.


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