Grants and Contributions:

Grant or Award spanning more than one fiscal year. (2017-2018 to 2022-2023)

In a 2002 Nature commentary, Paul Crutzen argued that human-driven climate warming has resulted in a shift in geological epochs, from the Holocene (H) to a new epoch dubbed the Anthropocene (A). This shift is at least as dramatic as, if not more so than, the shift about 11,500 years ago from the last ice age (P) to the modern (H). Due to the importance of the cryosphere in regulating high latitude ecosystems, the North is particularly susceptible to climate effects. Furthermore, warming in the Arctic is occurring two to three times faster than the increase in global mean surface temperatures, an effect known as polar amplification. Microorganisms are important drivers in Arctic systems, playing significant roles in nutrient cycling as well as carbon turnover and storage, and are also indicators of ecosystem changes through successional development of microbial community structure. As such, microbial communities can provide insight into changes in both ecosystem function and structure in a changing Northern environment.

My long-term objective is to determine the response of microbial communities to warming in the Arctic. Within this proposed research program, I plan to clarify how the structure and function of Northern microbial communities shift as a result of changing climate during the transition between different geological epochs. I will address these questions by: 1. Characterizing the extant and extinct microbial community shifts at the P/H transition, an analogue for current rapid climate change. 2. Characterizing modern microbial community response to glacier retreat and exposure of subglacial environments. 3. Determining the impact of a shift in dominance from thick, old multi-year sea ice to a thin, young first year sea ice on Arctic Ocean microbial sea ice communities.

I will be training two Ph.D. students and four M.Sc. students as well as 5-10 undergraduate research assistants. These projects will be independent, but will utilize similar tools and techniques, both in the field and in the laboratory. All students will interact closely with each other and with collaborators. In the field, we will use sound ecological sample design, well-dated and characterized field sites and conditions, and transplant experiments to obtain the ideal samples for our approach. We will characterize the environmental conditions extensively using standard approaches and gas flux analyses. We will utilize metagenomic approaches to characterize and compare microbial community structure and function. The result will be a detailed characterization of the interaction of climate, local environmental and historical conditions, and microbial community structure and function that will fundamentally enhance our knowledge of the response of soil microbial communities to a rapidly changing environment at the border between different geological epochs.