Beyond the Catastrophe: Meteorite impact structures as windows into subsurface microbial colonization
Presenter
Dr.
Haley
M.
Sapers
University
of
Southern
California
California
Institute
of
Technology
Jet
Propulsion
Lab
Abstract
The catastrophic biological effects of meteorite impact events are well established. However, meteorite impact events also create unique microbial niches that may have been significant habitats on early Earth and comprise understudied modern surface and subsurface ecosystems. The process of impact crating results in physical and chemical changes at multiple scales that facilitate microbial colonization. In turn, active microbial colonization will chemically and physically alter colonization substrates and these changes can be preserved as biosignatures. Any impact into a water-bearing target will generate a hydrothermal system characterized by extensive chemical and thermal disequilibria capable of hosting diverse metabolisms. An integrated multi-analytical approach to understanding the mineralogy, geochemistry, and habitability of post-impact environments provides the fundamental context for interpreting putative biosignatures of colonizing microorganisms and understanding constraints on modern colonization. Recent work has demonstrated that subsurface microbial communities represent unique assemblages. The observation of increased subsurface biomass in impactite lithologies suggests that meteorite impact structures may be unique systems to address fundamental questions in geobiology such as the mechanisms that control the distribution and activity of subsurface microbial communities.
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