Aotearoa as a model system to understand soil microbial responses to climate warming

Abstract

Soils contain the largest reservoir of carbon in the terrestrial biosphere and this carbon is vulnerable to degradation by soil microbial communities. As the climate warms microbial activity will increase, leading to acceleration of soil carbon losses. Despite its major importance for climate modelling and for understanding of ecosystem responses to climate change, the relationship between warming and soil microbial activity remains poorly constrained. This is due to a number of factors, but primarily because of methodological and conceptual limitations. In this presentation, I aim to provide a background on the temperature responses of soil microbial activity and present a theoretical framework to progress this area of research. I will explore experimental data collected from a range of soil temperatures across Aotearoa, including from along a unique soil geothermal gradient, to make predictions about soil microbial responses to warming. Using this data, I quantified adaptation rates of soil microbial respiration and found that it is decoupled from warming. This work highlights the exceptional opportunity we have here in Aotearoa to study large thermal gradients across relatively controlled environmental conditions. We can use this information to estimate potential for soil carbon losses with warming and generate novel hypotheses about evolutionary adaptation of soil microbial communities.