Microorganisms are ubiquitous and abundant on Earth. You inhale thousands of microbial cells in every breath and your body is home to 100 trillion of them. Only in the past few years have we been able to describe the enormous diversity of microorganisms that live in familiar environments, including your forehead, your computer keyboard, plant leaves, and the soil in your garden. Noah Fierer, Assistant Professor, Department of Ecology and Evolutionary Biology, and Fellow at the Institute for Research in Environmental Sciences at the University of Colorado at Boulder, will speak on Monday, March 19, from 7 – 8:30, in the Hunnewell Building at the Arnold Arboretum, about recent work exploring microbial diversity on the human body, the effects these organisms (most of which are not pathogenic) may have on our health, and how we may be able to use bacteria for forensic identification. He will also discuss ongoing work exploring bacterial diversity in the atmosphere through which unexpected sources of airborne bacteria in U.S. cities have been identified. He will finish by highlighting some future research directions in the burgeoning field of microbial ecology and how this research will likely alter how we think about â€˜germsâ€™ and human-microbe interactions. The lecture is free, but registration is required by calling 617-384-5277, or by visiting www.arboretum.harvard.edu.