CHANGES IN SOIL MICROBIAL COMMUNITIES AFTER LONG-TERM WARMING EXPOSURE

Microbial metabolism is a key controller of ecosystem processes (e.g., carbon cycling). However, we are only starting to identify the molecular mechanisms and feedback in response to long-term warming. My dissertation integrates multi-omics techniques to capture changes in soil microbial communities after long-term warming exposure. The research projects leverage three warming sites (i.e., SWaN, Barre Woods, and Prospect Hill) located in Western Massachusetts at Harvard Forest. These sites provided a unique experimental setup to better understand microbes in response to long-term temperature change. For the three research projects, we delved into the (i) microbial biodiversity across all three warming sites, (ii) integration of soil carbon chemistry and metatranscriptomics at the Barre Woods site, (iii) and a time series of soil metatranscriptomes at the Prospect Hill site. Overall, these studies revealed a broader scope of changes occurring with long-term warming than anticipated. The warming treatment induced shifts in fungi groups and recalcitrant carbon decomposer bacteria. Changes in microbial functions involved metabolic pathways associated to biogeochemical and cellular stability as result of nutrient limitation. Further, our results provided new insights in microbial response to chronic temperature stress, suggested an ongoing change in community structure and function, and linked soil carbon decrease to cellular processes using high throughput molecular techniques. This information will help to better understand interactions between microbial communities and the Earth’s climate