Speaker
Description
Soil bacteria are critical for sustaining ecosystem functions and services. Recent studies show that soil bacterial communities are susceptible to climate change, particularly to extreme climatic events. Yet, we know little about the biotic mechanisms through which extreme climatic events, such as heat waves, restructure soil bacterial communities. Previous studies indicate that slower growing bacterial species tend to dominate microbial communities as temperatures rise but most of these studies focus on temperatures comfortably within the organisms' thermal niche, assuming a constant community-wide mortality at all temperatures. We will address this research gap using four strains of soil-derived Pseudomonas bacteria, with two slower and two faster growing strains. After measuring the net growth rate and mortality of each strain in monoculture at different temperatures, this thermal niche experimental data will be used to parameterize a null model (i.e., without any biotic interactions) of community growth under various heat shocks and alternative models with only pairwise biotic interactions, or with pairwise and higher-order biotic interactions. To test our theoretical predictions, we will experimentally assemble all combinations of two, three, and four strain communities and measure their resistance to (i.e., immediate response to) and recovery from (i.e., response for several generations after) temperature extreme events. In this way, our work will use communities along a gradient of higher-order interactions to understand how various kinds of species interactions impact community stability under extreme temperature events.
