Microbial abundance in the deep subsurface of the Chesapeake Bay impact crater: Relationship to lithology and impact processes
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Abstract
Asteroid and comet impact events are known to cause profound disruption to surface ecosystems. The aseptic collection of samples throughout a 1.76-km-deep set of cores recovered from the deep subsurface of the Chesapeake Bay impact structure has allowed the study of the subsurface biosphere in a region disrupted by an impactor. Microbiological enumerations suggest the presence of three major microbiological zones. The upper zone (127–867 m) is characterized by a logarithmic decline in microbial abundance from the surface through the postimpact section of Miocene to Upper Eocene marine sediments and across the transition into the upper layers of the impact tsunami resurge sediments and sediment megablocks. In the middle zone (867–1397 m) microbial abundances are below detection. This zone is predominantly quartz sand, primarily composed of boulders and blocks, and it may have been mostly sterilized by the thermal pulse delivered during impact. No samples were collected from the large granite block (1096–1371 m). The lowest zone (below 1397 m) of increasing microbial abundance coincides with a region of heavily impact-fractured, hydraulically conductive suevite and fractured schist. These zones correspond to lithologies influenced by impact processes. Our results yield insights into the influence of impacts on the deep subsurface biosphere.
Study Area
Publication type | Article |
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Publication Subtype | Journal Article |
Title | Microbial abundance in the deep subsurface of the Chesapeake Bay impact crater: Relationship to lithology and impact processes |
Series title | GSA Special Papers |
DOI | 10.1130/2009.2458(40) |
Volume | 458 |
Year Published | 2009 |
Language | English |
Publisher | Geological Society of America |
Contributing office(s) | National Research Program - Eastern Branch |
Description | 10 p. |
First page | 941 |
Last page | 950 |
Country | United States |
State | Virginia |
Other Geospatial | Chesapeake Bay |
Online Only (Y/N) | N |
Additional Online Files (Y/N) | N |
Google Analytic Metrics | Metrics page |