Chapter 5
The Concept of Evanescent Microbial
Ecosystems in Earth’s Atmosphere
Dale Warren Griffin
Abstract This essay presents the hypothesis that short-lived or evanescent microbial ecosystems exist in Earth’s lower troposphere (~ < 4 km). This hypothesis is
supported by culture- and molecular-based studies that have shown diverse, viable,
and metabolically active microbial communities within Earth’s atmospheric boundary layer. Surprisingly, microorganisms are routinely recovered in samples collected
at extreme altitudes including those within the stratosphere (> 18 km). Volcanic
eruptions, dust storms, fires, and sea spray are known to seed the atmosphere with
microorganisms and to serve as potential nutrient sources while in the atmosphere
and upon deposition. Recent research has demonstrated that microorganisms are
metabolically active in clouds; for example, archaea capable of utilizing gases such
as methane and hydrogen-nitrogen have been identified in clouds and in the atmosphere over natural and anthropogenic gas seeps. The only difference between this
hypothesized ecosystem to more traditionally defined ecosystems is its evanescent
characteristics where clouds or gas plumes eventually dissipate as they reside over
and traverse Earth’s terrestrial and/or aquatic environments. The life cycle of these
hypothesized evanescent airborne ecosystems would be short-lived relative to the
classically defined biomes or ecosystems.
5.1 Essay
Similar to the many definitions of an ecosystem that can be found online, MerriamWebster’s definition is simply “the complex of a community of organisms and its
environment functioning as an ecological unit” (Merriam-Webster 2020). National
Geographic defines ecosystem as “An ecosystem is a geographic area where plants,
animals and other organisms, as well as weather and landscapes, work together to
form a bubble of life” (National-Geographic 2020). While many definitions of
D. W. Griffin (*)
Environmental and Public Health Microbiologist, U. S. Geological Survey, St. Petersburg, FL,
USA
e-mail: dgriffin@usgs.gov
© Springer Nature Switzerland AG 2021
C. J. Hurst (ed.), Microbes: The Foundation Stone of the Biosphere, Advances in
Environmental Microbiology 8, https://doi.org/10.1007/978-3-030-63512-1_5
105
The Concept of Evanescent Microbial
Ecosystems in Earth’s Atmosphere
Dale Warren Griffin
Abstract This essay presents the hypothesis that short-lived or evanescent microbial ecosystems exist in Earth’s lower troposphere (~ < 4 km). This hypothesis is
supported by culture- and molecular-based studies that have shown diverse, viable,
and metabolically active microbial communities within Earth’s atmospheric boundary layer. Surprisingly, microorganisms are routinely recovered in samples collected
at extreme altitudes including those within the stratosphere (> 18 km). Volcanic
eruptions, dust storms, fires, and sea spray are known to seed the atmosphere with
microorganisms and to serve as potential nutrient sources while in the atmosphere
and upon deposition. Recent research has demonstrated that microorganisms are
metabolically active in clouds; for example, archaea capable of utilizing gases such
as methane and hydrogen-nitrogen have been identified in clouds and in the atmosphere over natural and anthropogenic gas seeps. The only difference between this
hypothesized ecosystem to more traditionally defined ecosystems is its evanescent
characteristics where clouds or gas plumes eventually dissipate as they reside over
and traverse Earth’s terrestrial and/or aquatic environments. The life cycle of these
hypothesized evanescent airborne ecosystems would be short-lived relative to the
classically defined biomes or ecosystems.
5.1 Essay
Similar to the many definitions of an ecosystem that can be found online, MerriamWebster’s definition is simply “the complex of a community of organisms and its
environment functioning as an ecological unit” (Merriam-Webster 2020). National
Geographic defines ecosystem as “An ecosystem is a geographic area where plants,
animals and other organisms, as well as weather and landscapes, work together to
form a bubble of life” (National-Geographic 2020). While many definitions of
D. W. Griffin (*)
Environmental and Public Health Microbiologist, U. S. Geological Survey, St. Petersburg, FL,
USA
e-mail: dgriffin@usgs.gov
© Springer Nature Switzerland AG 2021
C. J. Hurst (ed.), Microbes: The Foundation Stone of the Biosphere, Advances in
Environmental Microbiology 8, https://doi.org/10.1007/978-3-030-63512-1_5
105