Survivability of Psychrobacter cryohalolentis K5 Under Simulated Martian Surface Conditions
Spacecraft launched to Mars can retain viable terrestrial microorganisms on board that may survive the interplanetary transit. Such biota might compromise the search for life beyond Earth if capable of propagating on Mars. The current study explored the survivability of Psychrobacter cryohalolentis...
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ftnasantrs:oai:casi.ntrs.nasa.gov:20130012502 2023-05-15T17:58:05+02:00 Survivability of Psychrobacter cryohalolentis K5 Under Simulated Martian Surface Conditions Schuerger, Andrew C. Bakermans, Corien Davidson, Mark M. Smith, David J. Onstott, Tullis Pacala, Stephen W. Unclassified, Unlimited, Publicly available April 14, 2008 application/pdf http://hdl.handle.net/2060/20130012502 unknown Document ID: 20130012502 http://hdl.handle.net/2060/20130012502 Copyright, Distribution under U.S. Government purpose rights CASI Exobiology KSC-2008-024 Astrobiology Science Conference 2008 (SETI); 14-17 Apr, 2008; Santa Clara, CA; United States 2008 ftnasantrs 2019-07-21T00:37:44Z Spacecraft launched to Mars can retain viable terrestrial microorganisms on board that may survive the interplanetary transit. Such biota might compromise the search for life beyond Earth if capable of propagating on Mars. The current study explored the survivability of Psychrobacter cryohalolentis K5, a psychrotolerant microorganism obtained from a Siberian permafrost cryopeg, under simulated martian surface conditions of high ultraviolet irradiation, high desiccation, low temperature, and low atmospheric pressure. First, a desiccation experiment compared the survival of P. cryohalolentis cells embedded, or not embedded, within a medium/salt matrix (MSM) maintained at 25 degrees C for 24 hr within a laminar flow hood. Results indicate that the presence of the MSM enhanced survival of the bacterial cells by 1 to 3 orders of magnitude. Second, tests were conducted in a Mars Simulation Chamber to determine the UV tolerance of the microorganism. No viable vegetative cells of P. cryohalolentis were detected after 8 hr of exposure to Mars-normal conditions of 4.55 W/m(2) UVC irradiation (200-280 nm), -12.5 degrees C, 7.1 mbar, and a Mars gas mix composed of CO2 (95.3%), N2 (2.7%), Ar (1.6%), O2 (0.2%), and H(2)O (0.03%). Third, an experiment was conducted within the Mars chamber in which total atmospheric opacities were simulated at tau = 0.1 (dust-free CO2 atmosphere at 7.1 mbar), 0.5 (normal clear sky with 0.4 = dust opacity and 0.1 = CO2-only opacity), and 3.5 (global dust storm) to determine the survivability of P. cryohalolentis to partially shielded UVC radiation. The survivability of the bacterium increased with the level of UVC attenuation, though population levels still declined several orders of magnitude compared to UVC-absent controls over an 8 hr exposure period. Other/Unknown Material permafrost NASA Technical Reports Server (NTRS) K5 ENVELOPE(24.794,24.794,67.805,67.805) |
institution |
Open Polar |
collection |
NASA Technical Reports Server (NTRS) |
op_collection_id |
ftnasantrs |
language |
unknown |
topic |
Exobiology |
spellingShingle |
Exobiology Schuerger, Andrew C. Bakermans, Corien Davidson, Mark M. Smith, David J. Onstott, Tullis Pacala, Stephen W. Survivability of Psychrobacter cryohalolentis K5 Under Simulated Martian Surface Conditions |
topic_facet |
Exobiology |
description |
Spacecraft launched to Mars can retain viable terrestrial microorganisms on board that may survive the interplanetary transit. Such biota might compromise the search for life beyond Earth if capable of propagating on Mars. The current study explored the survivability of Psychrobacter cryohalolentis K5, a psychrotolerant microorganism obtained from a Siberian permafrost cryopeg, under simulated martian surface conditions of high ultraviolet irradiation, high desiccation, low temperature, and low atmospheric pressure. First, a desiccation experiment compared the survival of P. cryohalolentis cells embedded, or not embedded, within a medium/salt matrix (MSM) maintained at 25 degrees C for 24 hr within a laminar flow hood. Results indicate that the presence of the MSM enhanced survival of the bacterial cells by 1 to 3 orders of magnitude. Second, tests were conducted in a Mars Simulation Chamber to determine the UV tolerance of the microorganism. No viable vegetative cells of P. cryohalolentis were detected after 8 hr of exposure to Mars-normal conditions of 4.55 W/m(2) UVC irradiation (200-280 nm), -12.5 degrees C, 7.1 mbar, and a Mars gas mix composed of CO2 (95.3%), N2 (2.7%), Ar (1.6%), O2 (0.2%), and H(2)O (0.03%). Third, an experiment was conducted within the Mars chamber in which total atmospheric opacities were simulated at tau = 0.1 (dust-free CO2 atmosphere at 7.1 mbar), 0.5 (normal clear sky with 0.4 = dust opacity and 0.1 = CO2-only opacity), and 3.5 (global dust storm) to determine the survivability of P. cryohalolentis to partially shielded UVC radiation. The survivability of the bacterium increased with the level of UVC attenuation, though population levels still declined several orders of magnitude compared to UVC-absent controls over an 8 hr exposure period. |
format |
Other/Unknown Material |
author |
Schuerger, Andrew C. Bakermans, Corien Davidson, Mark M. Smith, David J. Onstott, Tullis Pacala, Stephen W. |
author_facet |
Schuerger, Andrew C. Bakermans, Corien Davidson, Mark M. Smith, David J. Onstott, Tullis Pacala, Stephen W. |
author_sort |
Schuerger, Andrew C. |
title |
Survivability of Psychrobacter cryohalolentis K5 Under Simulated Martian Surface Conditions |
title_short |
Survivability of Psychrobacter cryohalolentis K5 Under Simulated Martian Surface Conditions |
title_full |
Survivability of Psychrobacter cryohalolentis K5 Under Simulated Martian Surface Conditions |
title_fullStr |
Survivability of Psychrobacter cryohalolentis K5 Under Simulated Martian Surface Conditions |
title_full_unstemmed |
Survivability of Psychrobacter cryohalolentis K5 Under Simulated Martian Surface Conditions |
title_sort |
survivability of psychrobacter cryohalolentis k5 under simulated martian surface conditions |
publishDate |
2008 |
url |
http://hdl.handle.net/2060/20130012502 |
op_coverage |
Unclassified, Unlimited, Publicly available |
long_lat |
ENVELOPE(24.794,24.794,67.805,67.805) |
geographic |
K5 |
geographic_facet |
K5 |
genre |
permafrost |
genre_facet |
permafrost |
op_source |
CASI |
op_relation |
Document ID: 20130012502 http://hdl.handle.net/2060/20130012502 |
op_rights |
Copyright, Distribution under U.S. Government purpose rights |
_version_ |
1766166620662661120 |