Rare Biosphere Portal

A New Paradigm for Microbiology.

The rare biosphere includes the tens of thousands of low-abundance taxa that make up the long tail seen in rank distribution curves for complex microbial communities. Recent discoveries show that the sheer size of the long tail is enormous and the genotypic varia-tion of rare microbes eclipses all prior estimates of bacterial, archaeal, and eukaryl diversity. We have few clues about why so many different kinds of low-abundance organisms occur in complex microbial communities, how they distribute across temporal and spatial scales, and what might be their contribution to community function. The rare biosphere contains numerous, never-before-seen populations because dominant microbes have masked their detection.

Over the last 100 years, biologists have developed an appreciation for the importance of microbial life and the overwhelming influence of abundant microbial populations on ecosystem function and habitability. We know far less about rare microbes. Their extreme diversity tells us that these low-abundance populations diverged from each other many millions of years ago, and that over geological time scales they function in as yet unidentified ways to sustain biological systems. To address gaping holes in our knowledge about the rare biosphere, we must identify the requisite elements for a broad, interdisciplinary, multi-component research initiative. Large in scale, the program would support experimentation and training, as well as the development of a theoretical framework for modeling the functional role of the rare biosphere. The focus will be to understand why the rare biosphere exists and the underlying mechanisms that allow low-abundance microbial populations to persist over different temporal scales. The initiative will explore the rare biosphere's contribution to biogeochemical processes and emergent properties of ecosystems, its influence on the shifts and evolution of community members and population structure, its capacity to reshape the composite genomes of microbial communities, and its potential role in regulating homeostatic mechanisms that impact human health and well being.