Microbial growth and carbon use efficiency show seasonal responses in a multifactorial climate change experiment

Eva Simon,Joana Séneca,Victoria Martin,Michael Bahn,Andreas Richter,Erich M Pötsch,Wolfgang Wanek,Theresa Böckle,David Reinthaler,Alberto Canarini,Hans-Peter Piepho

doi:10.1038/s42003-020-01317-1

Eva Simon, Joana Séneca + Show 9 more

Open Access

https://doi.org/10.1038/s42003-020-01317-1

Copy DOI

Abstract

Microbial growth and carbon use efficiency (CUE) are central to the global carbon cycle, as microbial remains form soil organic matter. We investigated how future global changes may affect soil microbial growth, respiration, and CUE. We aimed to elucidate the soil microbial response to multiple climate change drivers across the growing season and whether effects of multiple global change drivers on soil microbial physiology are additive or interactive. We measured soil microbial growth, CUE, and respiration at three time points in a field experiment combining three levels of temperature and atmospheric CO2, and a summer drought. Here we show that climate change-driven effects on soil microbial physiology are interactive and season-specific, while the coupled response of growth and respiration lead to stable microbial CUE (average CUE = 0.39). These results suggest that future research should focus on microbial growth across different seasons to understand and predict effects of global changes on soil carbon dynamics.

Highlights

Microbial growth and carbon use efficiency (CUE) are central to the global carbon cycle, as microbial remains form soil organic matter
The basis of the heterotrophic food web, is recycled back to the atmosphere as CO2, a fraction enters the soil as microbial necromass, comprising the dead residues of soil microorganisms, which make up a conspicuous proportion of soil organic matter[2,3]
This definition is a simplified view of microbial CUE, which reflects our current methodological limitations

Summary

Introduction

Microbial growth and carbon use efficiency (CUE) are central to the global carbon cycle, as microbial remains form soil organic matter. While it is widely recognized that microbial physiology and community composition are strongly affected by extrinsic factors such as temperature, water availability, and supply of recent plant-derived carbon[6,10,11,12], the response of growth and CUE of soil microbial communities to global change drivers are not yet fully resolved. This is due to, amongst other reasons, the scarcity of studies assessing microbial physiology in field-based long-term climate change experiments. These factors can have both direct and indirect effects on soil microbial physiology[13,14]

Objectives

Methods

Results