Microbial diversity is vast, and recent discoveries place soils as home to the most diverse of the Earth's microbial communities. The current project will probe a surprising response of microorganisms to changes in soil carbon availability: when new carbon enters soil, especially carbon that is easily assimilated and decomposed by soil microorganisms, a chain reaction occurs leading to the breakdown of older soil carbon, carbon that would otherwise have remained stable. Current theory does not explain this chain reaction. This project will test whether taxonomic biodiversity and the genetic biodiversity it supports - in other words, who is there and what are they doing - can explain this unusual carbon cycling phenomenon. Researchers will use long-term study sites in soils spanning a climatic gradient in Arizona and a variety of molecular, genomic, chemical and analytical approaches. The work will test the idea that parts of the carbon cycle are emergent consequences of interactions among organisms, with biodiversity as a fundamental driver, thereby connecting genes to communities to ecosystems.
The proposed work addresses important questions both in biodiversity science and the global carbon cycle, and is important because soil carbon is a major reservoir, storing about three times the amount of carbon contained in the atmosphere as carbon dioxide. Microbial biodiversity is the biological template upon which much of the carbon cycle unfolds, yet evidence of how diversity alters the soil carbon cycle remains elusive. This project will address this fundamental knowledge gap, generate information applicable to carbon management, train new scientists at the undergraduate, graduate, and post-doctoral levels, and engage the public through outreach activities.
