AUTHOR=Warren Steven D. 

TITLE=Microorganisms of the Phyllosphere: Origin, Transport, and Ecological Functions

JOURNAL=Frontiers in Forests and Global Change

VOLUME=Volume 5 - 2022

YEAR=2022

URL=https://www.frontiersin.org/journals/forests-and-global-change/articles/10.3389/ffgc.2022.843168

DOI=10.3389/ffgc.2022.843168

ISSN=2624-893X

ABSTRACT=Microbes are ubiquitous residents of the atmosphere. They are also present in terrestrial, marine, and aquatic environments. Typical microbes include viruses, fungi, archaea, bacteria, algae, and bryophytes. Most are of edaphic origin and play significant ecological roles in the soil. Propagules are exceedingly lightweight and small, generally measured in microns, i.e., millionths of a meter or thousandths of a millimeter. Propagules achieve airborne status in the wind, where they may travel from a few meters to thousands of kilometers. Most have been recorded at least as high as the stratosphere. While airborne, microbes may pass through multiple generations. Microbes in the atmosphere are generally accompanied by vast clouds of dust. They perform a variety of essential functions such as raindrop and snowflake condensation nuclei, without which there would be little or no precipitation. It is important to realize that all solid things that go up into the atmosphere must eventually return to the Earth. When precipitated or deposited back onto the Earth, they may land on and occupy any surface, including trees and other plants where they become epiphytic residents. They have been documented on broad-leaved and needle-leaved trees from deserts to tropical rainforests. If they land on bare soil, they often participate in biological soil crusts that are important for soil stabilization and for water and nutrient cycling.