A trait-based framework for predicting when and where microbial adaptation to climate change will affect ecosystem functioning

Abstract

As the earth system changes in response to human activities, a critical objective is to predict how biogeochemical process rates (e.g. nitrification, decomposition) and ecosystem function (e.g. net ecosystem productivity) will change under future conditions. A particular challenge is that the microbial communities that drive many of these processes are capable of adapting to environmental change in ways that alter ecosystem functioning. Despite evidence that microbes can adapt to temperature, precipitation regimes, and redox fluctuations, microbial communities are typically not optimally adapted to their local environment. For example, temperature optima for growth and enzyme activity are often greater than in situ temperatures in their environment. Here we discuss fundamental constraints on microbial adaptation and suggest specific environments where microbial adaptation to climate change (or lack thereof) is most likely to alter ecosystem functioning. Our framework is based on two principal assumptions.First, there are fundamental ecological trade-offs in microbial community traits that occur across environmental gradients (in time and space). These trade-offs result in shifting of microbial function (e.g. ability to take up resources at low temperature) in response to adaptation of another trait (e.g. limiting maintenance respiration at high temperature). Second, the mechanism and level of microbial community adaptation to changing environmental parameters is a function of the potential rate of change in community composition relative to the rate of environmental change. Together, this framework provides a basis for developing testable predictions about how the rate and degree of microbial adaptation to climate change will alter biogeochemical processes in aquatic and terrestrial ecosystems across the planet.

Microbial regulation of the soil carbon cycle: evidence from gene–enzyme relationships

“…In addition, this strong correlation also indicates that functional genes can be used to develop a gene-centric approach to integrate environmental genomics into simulation models in order to improve their predictive power and accuracy of ESMs (Reed et al, 2014). Regulatory pathways of the activity of enzymes involved in C degradation Identifying the structural-functional relationships for microbial organisms is particularly critical to determine the importance of the soil microbial community in regulating ecosystem processes, and thus there is keen interest in developing theoretical and experimental approaches to disentangle the microbial regulation of soil functions from other biotic and abiotic drivers (for example, Strickland et al, 2009;Wallenstein and Hall, 2012;Talbot et al, 2014;You et al, 2014;Wood et al, 2015). Albeit we found that functional genes were strongly related to enzyme activities, these results are correlative in nature and hence potentially non-causative.…”

Plant genetic effects on soils under climate change

“…Blankenship et al 2011;Wallenstein and Hall 2011), which may provide new selection pressures on plants via plant-soil feedbacks (e.g. Lau and Lennon 2011;Fig.…”

Dispersal-Based Microbial Community Assembly Decreases Biogeochemical Function

“…Recent attempts to link microbial communities and environmental biogeochemistry have yielded mixed results [1][2][3][4][5][6], leading researchers to propose the inclusion of community assembly mechanisms such as dispersal and selection in our understanding of biogeochemistry [2,[7][8][9]. Although much work has examined how assembly processes influence the maintenance of diversity and other ecosystem-level processes in macrobial systems [10][11][12][13], our comprehension of how these processes influence microbially-mediated biogeochemical cycles is still nascent [2,8,14].…”