Shortlisted for the 2024 Southwood Prize

Lijun Chen explores how bacterial-fungal interactions mediate soil organic carbon dynamics in the context of artificial forest ecosystems.

About the research

Overview

Eucalyptus is one of the most widely planted tree species worldwide. It has been demostrated that long-term short-rotation practices of eucalyptus induced to declining of soil organic carbon content and ecosystem services capacity. Exploring the patterns of soil organic carbon dynamic in eucalyptus plantations and key drivingforce are essential for promoting sustainable forest management and keeping the global carbon pool balance.

Landscape of eucalyptus plantation in Nanning city, China © Zhengye Wang

Bacteria and fungi have been described to be present in almost all ecosystems, and their spatial proximity can lead to either synergistic or antagonistic interactions. Ecological bacterial-fungal interaction are important for the fitness and colonisation rates of interacting partners, ultimately maintaining microbial diversity in various environments. The cross-kingdom interaction between bacteria and fungi have long been of interest to microbial ecologists, but how does their impact on the soil organic carbon dynamics? Understanding and quantifying the response of soil organic carbon to bacterial-fungal interactions is essential for regulating soil organic carbon dynamics.

Methodology

To address this gap, we gathered soil samples across four varying degrees of continuous cultivation in China, and assessed its impacts on soil carbon dynamic by examining several criteria about soil carbon cycling. We mainly focus on the mechanisms by which bacterial-fungal cross-kingdom interactions influence in mediate soil organic carbon decline in eucalyptus plantations.

Lijun investigating the soil profile during fieldwork © Jing Yang

Results and broader implications

Our results show continuous eucalyptus cultivation significantly reduces bacterial diversity while increasing fungal diversity, driving shifts in the community structures of both bacteria and fungi. This leads to an increase in negative cross-kingdom interactions between bacteria and fungi, which in turn enhances the activity of carbon-degrading enzymes and accelerates carbon mineralization.

Our research indicates that future management practices for eucalyptus plantations should reduce the number of continuous cultivation cycles to mitigate the loss of soil organic carbon caused by bacterial-fungal cross-kingdom interactions.

Summary of the study © Chen et al 2024

About the author

Current position

Currently, I am an associate professor at Central South University of Forestry and Technology. My research interests focus on the impact of plant-soil-microbe interactions on soil nutrient cycling, aiming to enhance the sustainable management of soil, thereby contributing to the improvement of human well-being.

Getting involved in ecology

Lijun gathering samples under eucalyptus © Huili Wang

From deep-sea hydrothermal vents to polar glaciers, and soil to gut, microorganisms participate in every aspect of ecosystems with astonishing diversity and adaptability. Microbial ecology is like opening an encyclopedia of life’s origins, evolution, and interactions, and fascinates me deeply. More importantly, microbe play an irreplaceable role in key ecological processes such as carbon cycling, nitrogen cycling, and pollutant degradation.

Studying in microbial ecology is not only about satisfying scientific curiosity but also about addressing major challenges like global climate change, environmental pollution, and human health. Which reveals how the smallest yet most powerful life shape our world, showing that even the tiniest organisms can have a profound impact on the future of our planet.

Current research focus

I continue to research the cross-kingdom interaction impacts on soil quality of forest ecosystems, agro-ecosystems and degraded land across mainland China and, as a continuation of the paper in Journal of Applied Ecology, we conducted a field experiment in two sites in south China, which continued more than three year. In this research we isolated the keystone strains of bacteria and fungi from eucalyptus soil to explore the temporal turnover of bacterial-fungal cross-kingdom interaction and its impacts on logging residues decay.

Read the full article “Integrating variation in bacterial-fungal co-occurrence network with soil carbon dynamics” in Journal of Applied Ecology.

Find the other early career researchers and their articles that have been shortlisted for the 2024 Southwood Prize here!