Connecting tiles of a mosaic: how one paper fit into a grand picture of Earth’s biogeochemical cycling

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One year ago, we published a paper in ISMEJ that revealed microbial taxa and traits associated with the decomposition of fast, slow, and passive soil organic carbon (SOC) pools from arctic tundra soil. For this paper, we coupled metagenomic analyses of soil microbial communities with estimated soil SOC decomposition parameters obtained through laboratory incubations. The intertwining of both these data sets was unique and provided insights that we could not have gained, had Ecosystem Ecologists and Microbial Ecologists not convened to study these complex processes.

Since its publication, additional studies from the tundra field site examined specific functional guilds of microbes impacted by warming. The funding that supported this work expanded beyond the tundra and included a companion site in the grassland prairie of Oklahoma. Microbial analyses from both sites revealed divergent responses of soil microbial communities to temperature and moisture shifts induced by climate warming.

One of the central goals that motivated all of this work was to inform climate models using microbial omics data. This effort proved to be a daunting task. Microbial functional genes and taxonomic markers are highly sensitive to environmental changes, so it was impossible to make projections from analyses taken over 1 or 2 years. However, with time, insights from many studies informed our understanding of the roles that microbes play in SOC cycling and the feedbacks that these processes have towards climate change. Eventually, a capstone publication produced a gene-informed model that predicts soil microbial respiration in response to temperature changes. This model predicted the thermal adaptation of microbial processes. If microbial adaptation reduces enhancements in CO2 evolution in response to warmer temperatures, this could moderate the positive feedback of warming in climate change scenarios. 

One of the main reasons that microbial data are typically omitted from climate models and global policy is the uncertainty and inconsistencies revealed in microbial ecology research. We do not have a clear understanding of soil microbial community associations with and feedbacks to climate change. However, papers like these are laying a foundation. Eventually, many initiatives are underway to bring awareness of soil microbial ecology to global policymakers and organizations. In 2020, a global collaborative initiative will launch the first-ever report on Global Soil Biodiversity per request of the United Nations. As research papers bring more certainty towards the grand picture of microbially-driven biogeochemical cycling, global and regional efforts can help ensure that these insights make the jump from the lab to policy and management.

Lauren Hale

Soil Scientist, USDA-ARS

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