CAREER: A research foundation to improve understanding of the post-thaw permafrost microbiome via collaboration networks and experiential learning

The Arctic is warming about four times faster than elsewhere on Earth, resulting in thaw of permafrost—permanently frozen soil underlying many Arctic landscapes. Permafrost occurs under approximately one fourth of the northern hemisphere's land surface and contains as much carbon (stored as undecomposed organic material) as the entire atmosphere. When permafrost thaws, microorganisms (such as fungi and bacteria) decompose and convert this organic material to carbon dioxide and methane, two of the most important greenhouse gases in our atmosphere.

This mechanism is referred to as positive climate feedback because the warming of permafrost generates higher concentrations of carbon dioxide and methane in the atmosphere which increases atmospheric temperatures even further. This permafrost–climate feedback is one of the least well-understood global climate feedbacks, partially due to our lack of understanding of permafrost microbial communities.

There is limited data about how permafrost thaw affects the microbial community—or microbiome—including the ecological processes underpinning the composition of the microbial community after permafrost thaws. New evidence shows that microbial communities are not only shaped by the environment in which they live, but that random chance—or coincidence—also determines which microbes are present at any given time.

The degree of coincidence influences our ability to predict microbiomes and their functions. The proposed work will deepen the understanding of the ecological processes that are shaping the post-thaw composition and activity of soil microorganisms. At the same time this project will train the next generation of polar researchers (at the postdoctoral, graduate, and undergraduate levels) and build a network of permafrost microbiologists able to address questions about the role of microorganisms in the permafrost–climate feedback.

The proposed work will improve understanding of the poorly known dynamics of post-thaw microbiomes in permafrost landscapes, which are rapidly changing due to the amplification of Arctic climate warming. The goal of the work is to address this knowledge gap through a series of heavily integrated research, education, and broader impacts activities. Specifically, this project will (1) synthesize publicly available and as-yet-unpublished DNA sequence data on post-thaw microbiomes from permafrost across the globe; (2) use ecological modeling to assess the contribution of stochasticity to the post-thaw microbiome composition over space, time, and disturbance intensity using a field sampling approach; (3) test mechanisms of assembly in post-thaw microbiomes in highly controlled laboratory incubations performed across many ecological axes; (4) equip the next generation of Arctic scholars and/or natural resource managers with the skills necessary to excel in scientific research, networking and collaboration, and science communication by training a postdoctoral researcher, a PhD student, and undergraduate and graduate students; (5) develop a professional network of permafrost microbial ecologists to elucidate the complex unknowns of permafrost and post-thaw microbiomes; and (6) support efforts to continue work in making polar and biogeosciences more diverse and inclusive.

Together, these activities will contribute to enhanced understanding of the permafrost–climate feedback, which will guide planning and policy.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.