https://microbewiki.kenyon.edu/index.php?title=Life_on_Mars&feed=atom&action=historyLife on Mars - Revision history2024-03-29T10:34:03ZRevision history for this page on the wikiMediaWiki 1.39.6https://microbewiki.kenyon.edu/index.php?title=Life_on_Mars&diff=65034&oldid=prevBarichD at 15:06, 13 July 20112011-07-13T15:06:33Z<p></p>
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<tr><td colspan="2" class="diff-side-deleted"></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;">{{Curated}}</ins></div></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>==Introduction==</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>==Introduction==</div></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>[[Image:Angryred.jpg|thumb|300px|right|Fig. 1 The "Bat-rat-spider-crab" from the 1959 science fiction film "The Angry Red Planet" is a highly unlikely form of Martian life. American International Pictures 1959.]]</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>[[Image:Angryred.jpg|thumb|300px|right|Fig. 1 The "Bat-rat-spider-crab" from the 1959 science fiction film "The Angry Red Planet" is a highly unlikely form of Martian life. American International Pictures 1959.]]</div></td></tr>
</table>BarichDhttps://microbewiki.kenyon.edu/index.php?title=Life_on_Mars&diff=64604&oldid=prevSteigmeyerA: /* Possible Types of Modern Martian Life */2011-05-12T05:14:15Z<p><span dir="auto"><span class="autocomment">Possible Types of Modern Martian Life</span></span></p>
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<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div><br><br><b>Martian Extremophiles<br></b></div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div><br><br><b>Martian Extremophiles<br></b></div></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div> Mars Express and the Mars Reconnaissance Orbiter have uncovered extensive deposits of concentrated sulphate salts, which suggest that Martian water was 10-100 times more saline than Earth seawater so if microorganisms exist there today, they would most likely be halophiles (Marlow et al. 2010). On Earth, most bacteria live in environments with an availability of water (a<sub>w</sub>) between 0.9 and 1.0, but some organisms, like <i>Xeromyces</i> fungi can exist in an a<sub>w</sub> as low as 0.6 (Marlow et al. 2010). Mars a<sub>w</sub> values at Meridani Planum range between 0.51 and 0.78 so it is conceivable that Earth-like halophiles could exists in that region. However, extreme halophiles on Earth that have adapted to these conditions, evolved from less tolerant organisms (Marlow et al. 2010) so these salt brines may not be able to support the formation of life. The Meridani Planum region has been osmotically challenging since the Noachian period (between 3 and 4 billion years ago) so it may have been difficult for life to arise there at all (Marlow et al. 2010). <br><br></div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div> Mars Express and the Mars Reconnaissance Orbiter have uncovered extensive deposits of concentrated sulphate salts, which suggest that Martian water was 10-100 times more saline than Earth seawater so if microorganisms exist there today, they would most likely be halophiles (Marlow et al. 2010). On Earth, most bacteria live in environments with an availability of water (a<sub>w</sub>) between 0.9 and 1.0, but some organisms, like <i>Xeromyces</i> fungi can exist in an a<sub>w</sub> as low as 0.6 (Marlow et al. 2010). Mars a<sub>w</sub> values at Meridani Planum range between 0.51 and 0.78 so it is conceivable that Earth-like halophiles could exists in that region. However, extreme halophiles on Earth that have adapted to these conditions, evolved from less tolerant organisms (Marlow et al. 2010) so these salt brines may not be able to support the formation of life. The Meridani Planum region has been osmotically challenging since the Noachian period (between 3 and 4 billion years ago) so it may have been difficult for life to arise there at all (Marlow et al. 2010). <br><br></div></td></tr>
<tr><td class="diff-marker" data-marker="−"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div> Another challenging aspect of these saline regions is their high acidity. The rover Opportunity detected jarosite, magnesium sulphates and calcium sulfates in this soil, suggesting not only a high concentration of salts, but also a high acidity (Stockton et al. 2010; Marlow et al. 2010). This would require some acidophilic mechanisms in any organisms living there. Some acidophiles will pump protons out of the intracellular space to maintain a neutral pH, while some organisms, like the Acetobacter aceti, utilize acid-stable proteins that prevent an over accumulation of cations (Marlow et al. 2010). There is precedent for extreme acidophiles like the achaea species <i>Picrophilus oshimae</i> that lives at a pH of 0.7. <br><br></div></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div> Another challenging aspect of these saline regions is their high acidity. The rover Opportunity detected jarosite, magnesium sulphates and calcium sulfates in this soil, suggesting not only a high concentration of salts, but also a high acidity (Stockton et al. 2010; Marlow et al. 2010). This would require some acidophilic mechanisms in any organisms living there. Some acidophiles will pump protons out of the intracellular space to maintain a neutral pH, while some organisms, like the <ins style="font-weight: bold; text-decoration: none;"><i></ins>Acetobacter aceti<ins style="font-weight: bold; text-decoration: none;"></i></ins>, utilize acid-stable proteins that prevent an over accumulation of cations (Marlow et al. 2010). There is precedent for extreme acidophiles like the achaea species <i>Picrophilus oshimae</i> that lives at a pH of 0.7. <br><br></div></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div> Though the northern halite crusts may offer protection from dessication and radiation (as long as the organisms are halophilic and acidophilic), they will not protect microbes from the harsh temperature fluctuations that occur across the planet. The Mars Global Surveyor observed Martian weather patterns for a year and recorded temperatures between -125°C and 25°C. Below the surface, the temperature would most likely be below the freezing point of water year-round (Marlow et al. 2010). However, there are instances where organisms can survive in nearly perpetually frozen environments. In Antarctica, the sun will cause localized melts in the ice for 150 days out of the year. These melted microhabitats are nutrient-rich solutions that become oases for microbes, including cyanobacteria (Priscu et al. 1998). In the nutrient-rich soils of Mars, it is conceivable that some pockets of frozen water could become liquefied long enough to support life. This is even more likely within the gypsum deposits, due to the mineral’s anti-freezing properties.</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div> Though the northern halite crusts may offer protection from dessication and radiation (as long as the organisms are halophilic and acidophilic), they will not protect microbes from the harsh temperature fluctuations that occur across the planet. The Mars Global Surveyor observed Martian weather patterns for a year and recorded temperatures between -125°C and 25°C. Below the surface, the temperature would most likely be below the freezing point of water year-round (Marlow et al. 2010). However, there are instances where organisms can survive in nearly perpetually frozen environments. In Antarctica, the sun will cause localized melts in the ice for 150 days out of the year. These melted microhabitats are nutrient-rich solutions that become oases for microbes, including cyanobacteria (Priscu et al. 1998). In the nutrient-rich soils of Mars, it is conceivable that some pockets of frozen water could become liquefied long enough to support life. This is even more likely within the gypsum deposits, due to the mineral’s anti-freezing properties.</div></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td></tr>
</table>SteigmeyerAhttps://microbewiki.kenyon.edu/index.php?title=Life_on_Mars&diff=64603&oldid=prevSteigmeyerA: /* Possible Types of Modern Martian Life */2011-05-12T05:13:40Z<p><span dir="auto"><span class="autocomment">Possible Types of Modern Martian Life</span></span></p>
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<td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">Revision as of 05:13, 12 May 2011</td>
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<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div><br><br>It is possible that some form of life existed on Mars in the past with its thick atmosphere, warmer temperatures, mineral deposits and abundant water. Even if extremophiles were able to survive the planet’s dramatic climate changes, were they able to evolve fast enough to exist on modern-day Mars? Extra-terrestrial oxidized organic molecules, like aldehydes and keytones, have been detected in the Murchison meteorite (Stockton et al. 2010) so it is likely that evidence of organic metabolic processes could be found on Mars. The first probes on Mars may have detected evidence of biochemical processes but their sensors were not sensitive enough to give definitive results (Handwerk 2006). Recently, the Mars Organic Analyzer on the Phoneix Lander successfully detected acetone in a Mars soil sample and found that these types of molecules have a short lifespan when exposed to the atmosphere (Fig. 8) (Stockton et al. 2010, Johnson et al. 2011). This not only offers a possible explanation for why the Viking landers’ results were inconclusive, but, more importantly, shows that organic molecules cannot survive on the surface, but do exist under the soil. If living microorganisms exist under the soil, what form would they take?</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div><br><br>It is possible that some form of life existed on Mars in the past with its thick atmosphere, warmer temperatures, mineral deposits and abundant water. Even if extremophiles were able to survive the planet’s dramatic climate changes, were they able to evolve fast enough to exist on modern-day Mars? Extra-terrestrial oxidized organic molecules, like aldehydes and keytones, have been detected in the Murchison meteorite (Stockton et al. 2010) so it is likely that evidence of organic metabolic processes could be found on Mars. The first probes on Mars may have detected evidence of biochemical processes but their sensors were not sensitive enough to give definitive results (Handwerk 2006). Recently, the Mars Organic Analyzer on the Phoneix Lander successfully detected acetone in a Mars soil sample and found that these types of molecules have a short lifespan when exposed to the atmosphere (Fig. 8) (Stockton et al. 2010, Johnson et al. 2011). This not only offers a possible explanation for why the Viking landers’ results were inconclusive, but, more importantly, shows that organic molecules cannot survive on the surface, but do exist under the soil. If living microorganisms exist under the soil, what form would they take?</div></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div><br><br><b>Martian Extremophiles<br></b></div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div><br><br><b>Martian Extremophiles<br></b></div></td></tr>
<tr><td class="diff-marker" data-marker="−"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div> Mars Express and the Mars Reconnaissance Orbiter have uncovered extensive deposits of concentrated sulphate salts, which suggest that Martian water was 10-100 times more saline than Earth seawater so if microorganisms exist there today, they would most likely be halophiles (Marlow et al. 2010). On Earth, most bacteria live in environments with an availability of water (<del style="font-weight: bold; text-decoration: none;">aw</del>) between 0.9 and 1.0, but some organisms, like <i>Xeromyces</i> fungi can exist in an <del style="font-weight: bold; text-decoration: none;">aw </del>as low as 0.6 (Marlow et al. 2010). Mars <del style="font-weight: bold; text-decoration: none;">aw </del>values at Meridani Planum range between 0.51 and 0.78 so it is conceivable that Earth-like halophiles could exists in that region. However, extreme halophiles on Earth that have adapted to these conditions, evolved from less tolerant organisms (Marlow et al. 2010) so these salt brines may not be able to support the formation of life. The Meridani Planum region has been osmotically challenging since the Noachian period (between 3 and 4 billion years ago) so it may have been difficult for life to arise there at all (Marlow et al. 2010). <br><br></div></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div> Mars Express and the Mars Reconnaissance Orbiter have uncovered extensive deposits of concentrated sulphate salts, which suggest that Martian water was 10-100 times more saline than Earth seawater so if microorganisms exist there today, they would most likely be halophiles (Marlow et al. 2010). On Earth, most bacteria live in environments with an availability of water (<ins style="font-weight: bold; text-decoration: none;">a<sub>w</sub></ins>) between 0.9 and 1.0, but some organisms, like <i>Xeromyces</i> fungi can exist in an <ins style="font-weight: bold; text-decoration: none;">a<sub>w</sub> </ins>as low as 0.6 (Marlow et al. 2010). Mars <ins style="font-weight: bold; text-decoration: none;">a<sub>w</sub> </ins>values at Meridani Planum range between 0.51 and 0.78 so it is conceivable that Earth-like halophiles could exists in that region. However, extreme halophiles on Earth that have adapted to these conditions, evolved from less tolerant organisms (Marlow et al. 2010) so these salt brines may not be able to support the formation of life. The Meridani Planum region has been osmotically challenging since the Noachian period (between 3 and 4 billion years ago) so it may have been difficult for life to arise there at all (Marlow et al. 2010). <br><br></div></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div> Another challenging aspect of these saline regions is their high acidity. The rover Opportunity detected jarosite, magnesium sulphates and calcium sulfates in this soil, suggesting not only a high concentration of salts, but also a high acidity (Stockton et al. 2010; Marlow et al. 2010). This would require some acidophilic mechanisms in any organisms living there. Some acidophiles will pump protons out of the intracellular space to maintain a neutral pH, while some organisms, like the Acetobacter aceti, utilize acid-stable proteins that prevent an over accumulation of cations (Marlow et al. 2010). There is precedent for extreme acidophiles like the achaea species <i>Picrophilus oshimae</i> that lives at a pH of 0.7. <br><br></div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div> Another challenging aspect of these saline regions is their high acidity. The rover Opportunity detected jarosite, magnesium sulphates and calcium sulfates in this soil, suggesting not only a high concentration of salts, but also a high acidity (Stockton et al. 2010; Marlow et al. 2010). This would require some acidophilic mechanisms in any organisms living there. Some acidophiles will pump protons out of the intracellular space to maintain a neutral pH, while some organisms, like the Acetobacter aceti, utilize acid-stable proteins that prevent an over accumulation of cations (Marlow et al. 2010). There is precedent for extreme acidophiles like the achaea species <i>Picrophilus oshimae</i> that lives at a pH of 0.7. <br><br></div></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div> Though the northern halite crusts may offer protection from dessication and radiation (as long as the organisms are halophilic and acidophilic), they will not protect microbes from the harsh temperature fluctuations that occur across the planet. The Mars Global Surveyor observed Martian weather patterns for a year and recorded temperatures between -125°C and 25°C. Below the surface, the temperature would most likely be below the freezing point of water year-round (Marlow et al. 2010). However, there are instances where organisms can survive in nearly perpetually frozen environments. In Antarctica, the sun will cause localized melts in the ice for 150 days out of the year. These melted microhabitats are nutrient-rich solutions that become oases for microbes, including cyanobacteria (Priscu et al. 1998). In the nutrient-rich soils of Mars, it is conceivable that some pockets of frozen water could become liquefied long enough to support life. This is even more likely within the gypsum deposits, due to the mineral’s anti-freezing properties.</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div> Though the northern halite crusts may offer protection from dessication and radiation (as long as the organisms are halophilic and acidophilic), they will not protect microbes from the harsh temperature fluctuations that occur across the planet. The Mars Global Surveyor observed Martian weather patterns for a year and recorded temperatures between -125°C and 25°C. Below the surface, the temperature would most likely be below the freezing point of water year-round (Marlow et al. 2010). However, there are instances where organisms can survive in nearly perpetually frozen environments. In Antarctica, the sun will cause localized melts in the ice for 150 days out of the year. These melted microhabitats are nutrient-rich solutions that become oases for microbes, including cyanobacteria (Priscu et al. 1998). In the nutrient-rich soils of Mars, it is conceivable that some pockets of frozen water could become liquefied long enough to support life. This is even more likely within the gypsum deposits, due to the mineral’s anti-freezing properties.</div></td></tr>
</table>SteigmeyerAhttps://microbewiki.kenyon.edu/index.php?title=Life_on_Mars&diff=64602&oldid=prevSteigmeyerA: /* Possible Methods of Microbial Survival */2011-05-12T05:11:33Z<p><span dir="auto"><span class="autocomment">Possible Methods of Microbial Survival</span></span></p>
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<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div><br>[[Image:Mars Salt.gif|thumb|300px|right|Fig. 7 False color image from the Mars Odyssey's Thermal Emission Omaging system showing spectrally distinct materials laid out in a flowing pattern indicative of water (shown by red arrows). These mineral distributions most likely consist of chloride salts. Osterloo et al. 2008. ]]</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div><br>[[Image:Mars Salt.gif|thumb|300px|right|Fig. 7 False color image from the Mars Odyssey's Thermal Emission Omaging system showing spectrally distinct materials laid out in a flowing pattern indicative of water (shown by red arrows). These mineral distributions most likely consist of chloride salts. Osterloo et al. 2008. ]]</div></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div> Using data from the Thermal Emission Imaging System on the Mars Odyssey and supporting data from the orbiting probes Mars Global Surveyor and Mars Reconnaissance Orbiter, Osterloo et al detected the presence of chloride salts on Mars (Fig. 7) These saline minerals were deposited in the soil either after weathering of basaltic rocks or through erosion created by ancient lakes and rivers. As these bodies evaporated, the salts precipitated from the solution and left deposits spotted across the planet (Osterloo et al. 2008; Stivaletta et al. 2009). When exposed to this level of salinity in a laboratory Mars-analogue environment, <i>E. coli</i> were able to survive, but there was no increase in their density or population size (Berry et al. 2010). It is therefore feasible that organisms could live in the Martian soil if they are properly adapted.<br><br></div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div> Using data from the Thermal Emission Imaging System on the Mars Odyssey and supporting data from the orbiting probes Mars Global Surveyor and Mars Reconnaissance Orbiter, Osterloo et al detected the presence of chloride salts on Mars (Fig. 7) These saline minerals were deposited in the soil either after weathering of basaltic rocks or through erosion created by ancient lakes and rivers. As these bodies evaporated, the salts precipitated from the solution and left deposits spotted across the planet (Osterloo et al. 2008; Stivaletta et al. 2009). When exposed to this level of salinity in a laboratory Mars-analogue environment, <i>E. coli</i> were able to survive, but there was no increase in their density or population size (Berry et al. 2010). It is therefore feasible that organisms could live in the Martian soil if they are properly adapted.<br><br></div></td></tr>
<tr><td class="diff-marker" data-marker="−"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div> The presence of these deposits, and their similarity to the sabkhas on Earth, have made halophilic organisms a likely candidate for life on Mars (Stivaletta et al. 2009). On Earth, prokaryotic inhabitants of sabkhas (salt flats) accumulate KCl in their cells to maintain osmotic similarity to the surrounding soil (Stivaletta et al. 2009). But severe osmotic difference with the environment is not the only threat that these organisms have adapted to on Earth. Halophiles living in sabkhas face drastic temperature changes and severely dry conditions. To solve these problems, the organisms seek shelter in the gypsum crystals of halite crusts <del style="font-weight: bold; text-decoration: none;">—prominent </del>features of the Martian surface. </div></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div> The presence of these deposits, and their similarity to the sabkhas on Earth, have made halophilic organisms a likely candidate for life on Mars (Stivaletta et al. 2009). On Earth, prokaryotic inhabitants of sabkhas (salt flats) accumulate KCl in their cells to maintain osmotic similarity to the surrounding soil (Stivaletta et al. 2009). But severe osmotic difference with the environment is not the only threat that these organisms have adapted to on Earth. Halophiles living in sabkhas face drastic temperature changes and severely dry conditions. To solve these problems, the organisms seek shelter in the gypsum crystals of halite crusts <ins style="font-weight: bold; text-decoration: none;">— prominent </ins>features of the Martian surface. </div></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div><br><br><b>Halite and Gypsum Shelters</b><br></div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div><br><br><b>Halite and Gypsum Shelters</b><br></div></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div> The Atacama Desert of Chile is considered to be a close analogue of Mars due to its low average precipitation (less that 1m per year) and 3-4 million years of persistent hyperarid conditions (Wierzchos et al. 2010). The basic soils in this desert harbor little to no life but the halite crusts, which contain microporous gypsum crystals, are abounding with photosynthetic microorganisms, suggesting that it was sought as a refuge once the area dried millions of years ago. This microhabitat supports organisms across different phyla including cyanobacteria and proto-bacterial lineages (Wierzchos et al. 2010). <br><br></div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div> The Atacama Desert of Chile is considered to be a close analogue of Mars due to its low average precipitation (less that 1m per year) and 3-4 million years of persistent hyperarid conditions (Wierzchos et al. 2010). The basic soils in this desert harbor little to no life but the halite crusts, which contain microporous gypsum crystals, are abounding with photosynthetic microorganisms, suggesting that it was sought as a refuge once the area dried millions of years ago. This microhabitat supports organisms across different phyla including cyanobacteria and proto-bacterial lineages (Wierzchos et al. 2010). <br><br></div></td></tr>
</table>SteigmeyerAhttps://microbewiki.kenyon.edu/index.php?title=Life_on_Mars&diff=64601&oldid=prevSteigmeyerA: /* Possible Methods of Microbial Survival */2011-05-12T05:10:45Z<p><span dir="auto"><span class="autocomment">Possible Methods of Microbial Survival</span></span></p>
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<td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">Revision as of 05:10, 12 May 2011</td>
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<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div><br>[[Image:Mars Salt.gif|thumb|300px|right|Fig. 7 False color image from the Mars Odyssey's Thermal Emission Omaging system showing spectrally distinct materials laid out in a flowing pattern indicative of water (shown by red arrows). These mineral distributions most likely consist of chloride salts. Osterloo et al. 2008. ]]</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div><br>[[Image:Mars Salt.gif|thumb|300px|right|Fig. 7 False color image from the Mars Odyssey's Thermal Emission Omaging system showing spectrally distinct materials laid out in a flowing pattern indicative of water (shown by red arrows). These mineral distributions most likely consist of chloride salts. Osterloo et al. 2008. ]]</div></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div> Using data from the Thermal Emission Imaging System on the Mars Odyssey and supporting data from the orbiting probes Mars Global Surveyor and Mars Reconnaissance Orbiter, Osterloo et al detected the presence of chloride salts on Mars (Fig. 7) These saline minerals were deposited in the soil either after weathering of basaltic rocks or through erosion created by ancient lakes and rivers. As these bodies evaporated, the salts precipitated from the solution and left deposits spotted across the planet (Osterloo et al. 2008; Stivaletta et al. 2009). When exposed to this level of salinity in a laboratory Mars-analogue environment, <i>E. coli</i> were able to survive, but there was no increase in their density or population size (Berry et al. 2010). It is therefore feasible that organisms could live in the Martian soil if they are properly adapted.<br><br></div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div> Using data from the Thermal Emission Imaging System on the Mars Odyssey and supporting data from the orbiting probes Mars Global Surveyor and Mars Reconnaissance Orbiter, Osterloo et al detected the presence of chloride salts on Mars (Fig. 7) These saline minerals were deposited in the soil either after weathering of basaltic rocks or through erosion created by ancient lakes and rivers. As these bodies evaporated, the salts precipitated from the solution and left deposits spotted across the planet (Osterloo et al. 2008; Stivaletta et al. 2009). When exposed to this level of salinity in a laboratory Mars-analogue environment, <i>E. coli</i> were able to survive, but there was no increase in their density or population size (Berry et al. 2010). It is therefore feasible that organisms could live in the Martian soil if they are properly adapted.<br><br></div></td></tr>
<tr><td class="diff-marker" data-marker="−"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div> The presence of these deposits, and their similarity to the sabkhas on Earth, have made halophilic organisms a likely candidate for life on Mars (Stivaletta et al. 2009). On Earth, prokaryotic inhabitants of sabkhas (salt flats) accumulate <del style="font-weight: bold; text-decoration: none;">KCL </del>in their cells to maintain osmotic similarity to the surrounding soil (Stivaletta et al. 2009). But severe osmotic difference with the environment is not the only threat that these organisms have adapted to on Earth. Halophiles living in sabkhas face drastic temperature changes and severely dry conditions. To solve these problems, the organisms seek shelter in the gypsum crystals of halite crusts —prominent features of the Martian surface. </div></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div> The presence of these deposits, and their similarity to the sabkhas on Earth, have made halophilic organisms a likely candidate for life on Mars (Stivaletta et al. 2009). On Earth, prokaryotic inhabitants of sabkhas (salt flats) accumulate <ins style="font-weight: bold; text-decoration: none;">KCl </ins>in their cells to maintain osmotic similarity to the surrounding soil (Stivaletta et al. 2009). But severe osmotic difference with the environment is not the only threat that these organisms have adapted to on Earth. Halophiles living in sabkhas face drastic temperature changes and severely dry conditions. To solve these problems, the organisms seek shelter in the gypsum crystals of halite crusts —prominent features of the Martian surface. </div></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div><br><br><b>Halite and Gypsum Shelters</b><br></div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div><br><br><b>Halite and Gypsum Shelters</b><br></div></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div> The Atacama Desert of Chile is considered to be a close analogue of Mars due to its low average precipitation (less that 1m per year) and 3-4 million years of persistent hyperarid conditions (Wierzchos et al. 2010). The basic soils in this desert harbor little to no life but the halite crusts, which contain microporous gypsum crystals, are abounding with photosynthetic microorganisms, suggesting that it was sought as a refuge once the area dried millions of years ago. This microhabitat supports organisms across different phyla including cyanobacteria and proto-bacterial lineages (Wierzchos et al. 2010). <br><br></div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div> The Atacama Desert of Chile is considered to be a close analogue of Mars due to its low average precipitation (less that 1m per year) and 3-4 million years of persistent hyperarid conditions (Wierzchos et al. 2010). The basic soils in this desert harbor little to no life but the halite crusts, which contain microporous gypsum crystals, are abounding with photosynthetic microorganisms, suggesting that it was sought as a refuge once the area dried millions of years ago. This microhabitat supports organisms across different phyla including cyanobacteria and proto-bacterial lineages (Wierzchos et al. 2010). <br><br></div></td></tr>
</table>SteigmeyerAhttps://microbewiki.kenyon.edu/index.php?title=Life_on_Mars&diff=64600&oldid=prevSteigmeyerA: /* Possible Methods of Microbial Survival */2011-05-12T05:10:08Z<p><span dir="auto"><span class="autocomment">Possible Methods of Microbial Survival</span></span></p>
<table style="background-color: #fff; color: #202122;" data-mw="interface">
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<td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">Revision as of 05:10, 12 May 2011</td>
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<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>[[Image:Phoenix Water.jpg|thumb|300px|right|Fig. 6 Water droplets condensed on the leg of the Phoenix Lander in the early morning mists. Credit: The Telegraph, 19 March 2009.]]</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>[[Image:Phoenix Water.jpg|thumb|300px|right|Fig. 6 Water droplets condensed on the leg of the Phoenix Lander in the early morning mists. Credit: The Telegraph, 19 March 2009.]]</div></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div> When Mars’ atmosphere deteriorated and the planet cooled, much of the water on the surface and in the atmosphere evaporated into space. However, there is strong evidence to suggest that large amounts of water were absorbed into the soil and remain to this day in the form of ice. The Phoenix Lander uncovered ice just below the surface and the Mars Reconnaissance Orbiter detected a white material, which appears in craters following meteorite impact and fades over time (Marlow et al.). Though it may be possible for organisms to use the water-ice, a prominent source of water could be in the supposedly low-water atmosphere. Just before and shortly after sunrise, the moisture level on Mars is close to saturation. The Phoenix Lander observed ground fogs forming and drops of liquid water condensed on the lander’s legs (Fig. 6) (Schulze-Makuch 2010). Environments with high relative humidity (RH) can trigger the metabolic activity of phototrophic organisms, even without the condensation of water. The cryptoendolithic lichens in Death Valley sandstone, for example, will begin photosynthetic processes at RH greater than 70% (Wierzchos et al. 2010). On Mars, though, the key to xerophilic organisms’ ability to utilize water vapor may lie in the properties of Perchlorate. <br><br></div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div> When Mars’ atmosphere deteriorated and the planet cooled, much of the water on the surface and in the atmosphere evaporated into space. However, there is strong evidence to suggest that large amounts of water were absorbed into the soil and remain to this day in the form of ice. The Phoenix Lander uncovered ice just below the surface and the Mars Reconnaissance Orbiter detected a white material, which appears in craters following meteorite impact and fades over time (Marlow et al.). Though it may be possible for organisms to use the water-ice, a prominent source of water could be in the supposedly low-water atmosphere. Just before and shortly after sunrise, the moisture level on Mars is close to saturation. The Phoenix Lander observed ground fogs forming and drops of liquid water condensed on the lander’s legs (Fig. 6) (Schulze-Makuch 2010). Environments with high relative humidity (RH) can trigger the metabolic activity of phototrophic organisms, even without the condensation of water. The cryptoendolithic lichens in Death Valley sandstone, for example, will begin photosynthetic processes at RH greater than 70% (Wierzchos et al. 2010). On Mars, though, the key to xerophilic organisms’ ability to utilize water vapor may lie in the properties of Perchlorate. <br><br></div></td></tr>
<tr><td class="diff-marker" data-marker="−"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div> Perchlorates are powerful oxidizers, can work as anti-freeze agents and are very hygroscopic (Schulze-Makuch 2010). The Phoenix Lander detected high concentrations of this chemical in the Martian soil (Marlow et al. 2010). Martian microbes could incorporate Perchlorates into their metabolism and use it to obtain water from the atmosphere. On Earth, Perchlorate-reducing bacteria exist in anoxic environments by oxidizing organic carbon or inorganic donors like <del style="font-weight: bold; text-decoration: none;">H2</del>, <del style="font-weight: bold; text-decoration: none;">H2S </del>or <del style="font-weight: bold; text-decoration: none;">Fe2</del>+ and couple that oxidation to Perchlorate reduction (Schulze-Makuch 2010). On Mars, Xerophilic microbes could use the antifreeze properties of Perchlorate to survive the cold temperatures, the hygroscopic properties to pull water from the early morning mists and the oxidizer properties for chemical processes. Earth organisms with these adaptations are usually halophilic, favoring salt water as an internal solvent (Schulze-Makuch 2010). Perhaps not coincidentally, many of the evaporite deposits suggest a high-salt content in the Martian soil. </div></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div> Perchlorates are powerful oxidizers, can work as anti-freeze agents and are very hygroscopic (Schulze-Makuch 2010). The Phoenix Lander detected high concentrations of this chemical in the Martian soil (Marlow et al. 2010). Martian microbes could incorporate Perchlorates into their metabolism and use it to obtain water from the atmosphere. On Earth, Perchlorate-reducing bacteria exist in anoxic environments by oxidizing organic carbon or inorganic donors like <ins style="font-weight: bold; text-decoration: none;">H<sub>2</sub></ins>, <ins style="font-weight: bold; text-decoration: none;">H<sub>2</sub>S </ins>or <ins style="font-weight: bold; text-decoration: none;">Fe<sup>2</ins>+<ins style="font-weight: bold; text-decoration: none;"></sup> </ins>and couple that oxidation to Perchlorate reduction (Schulze-Makuch 2010). On Mars, Xerophilic microbes could use the antifreeze properties of Perchlorate to survive the cold temperatures, the hygroscopic properties to pull water from the early morning mists and the oxidizer properties for chemical processes. Earth organisms with these adaptations are usually halophilic, favoring salt water as an internal solvent (Schulze-Makuch 2010). Perhaps not coincidentally, many of the evaporite deposits suggest a high-salt content in the Martian soil. </div></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div><br><br><b>Salinity on Mars</b><br></div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div><br><br><b>Salinity on Mars</b><br></div></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div><br>[[Image:Mars Salt.gif|thumb|300px|right|Fig. 7 False color image from the Mars Odyssey's Thermal Emission Omaging system showing spectrally distinct materials laid out in a flowing pattern indicative of water (shown by red arrows). These mineral distributions most likely consist of chloride salts. Osterloo et al. 2008. ]]</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div><br>[[Image:Mars Salt.gif|thumb|300px|right|Fig. 7 False color image from the Mars Odyssey's Thermal Emission Omaging system showing spectrally distinct materials laid out in a flowing pattern indicative of water (shown by red arrows). These mineral distributions most likely consist of chloride salts. Osterloo et al. 2008. ]]</div></td></tr>
</table>SteigmeyerAhttps://microbewiki.kenyon.edu/index.php?title=Life_on_Mars&diff=64599&oldid=prevSteigmeyerA: /* Notable Mars Missions and Findings */2011-05-12T05:06:45Z<p><span dir="auto"><span class="autocomment">Notable Mars Missions and Findings</span></span></p>
<table style="background-color: #fff; color: #202122;" data-mw="interface">
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<td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">Revision as of 05:06, 12 May 2011</td>
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<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>[[Image:Mars Methane.jpg|thumb|300px|right|Fig. 2 Concentrations of methane observed on Mars by the Mars Express Orbiter. Credit: NASA.]]</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>[[Image:Mars Methane.jpg|thumb|300px|right|Fig. 2 Concentrations of methane observed on Mars by the Mars Express Orbiter. Credit: NASA.]]</div></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div><br><b>Viking 1 and 2</b> — Reached Martian surface on July 20, 1976 and September 1976, respectively. These landers were designed to analyze the Martian soil, atmosphere composition, weather and geographic features. The labeled-release experiment found that organic material was consumed when exposed to a soil sample, as if life were present. This contradicted a gas-chromatography experiment that yielded no evidence of organic compounds in the soil (Navarro-Gonzalez 2003). However, recent evidence suggests that these may have been low levels of organic compounds that the experiments were not sensitive enough to analyze, or that the organic compounds were too stable to be converted into a gas and thus were undetectable in the spectral analysis. (Handwerk 2006). </div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div><br><b>Viking 1 and 2</b> — Reached Martian surface on July 20, 1976 and September 1976, respectively. These landers were designed to analyze the Martian soil, atmosphere composition, weather and geographic features. The labeled-release experiment found that organic material was consumed when exposed to a soil sample, as if life were present. This contradicted a gas-chromatography experiment that yielded no evidence of organic compounds in the soil (Navarro-Gonzalez 2003). However, recent evidence suggests that these may have been low levels of organic compounds that the experiments were not sensitive enough to analyze, or that the organic compounds were too stable to be converted into a gas and thus were undetectable in the spectral analysis. (Handwerk 2006). </div></td></tr>
<tr><td class="diff-marker" data-marker="−"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div><br><br><b>Mars Global Surveyor </b> — Reached Mars orbit on September 12, 1997 and was operational through 2006. This orbiter was designed for extensive mapping of Mars and the study of daily weather patterns. It recorded images of gullies, debris flows and other evidence of surface water in Mars’ distant past as well as CO<sub>2</sub ice, which is slowly receding at the poles (NASA JPL). </div></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><br><br><b>Mars Global Surveyor </b> — Reached Mars orbit on September 12, 1997 and was operational through 2006. This orbiter was designed for extensive mapping of Mars and the study of daily weather patterns. It recorded images of gullies, debris flows and other evidence of surface water in Mars’ distant past as well as CO<sub>2</sub<ins style="font-weight: bold; text-decoration: none;">> </ins>ice, which is slowly receding at the poles (NASA JPL). </div></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div><br><br><b>Mars Pathfinder </b>— The first successful lander since the Viking program, the rover Sojourner was designed to analyze the geological history of Mars, determine soil composition and look for signs of life. The landing site (Fig. 4) was selected because scientists believed that the area had once been the subjected to a large flood. The mission provided evidence suggesting that Mars had a warmer and wetter climate in the past (NASA JPL). </div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div><br><br><b>Mars Pathfinder </b>— The first successful lander since the Viking program, the rover Sojourner was designed to analyze the geological history of Mars, determine soil composition and look for signs of life. The landing site (Fig. 4) was selected because scientists believed that the area had once been the subjected to a large flood. The mission provided evidence suggesting that Mars had a warmer and wetter climate in the past (NASA JPL). </div></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div><br><br><b>Mars Odyssey </b>— The orbiter arrived at Mars on October 24, 2001 and conducted a planet-wide geological survey mission. It successfully mapped out mineral deposits across the planet and identified areas of water-ice just below the surface. The probe also determined that radiation in low-Mars orbit is twice that in low-Earth orbit (NASA JPL).</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div><br><br><b>Mars Odyssey </b>— The orbiter arrived at Mars on October 24, 2001 and conducted a planet-wide geological survey mission. It successfully mapped out mineral deposits across the planet and identified areas of water-ice just below the surface. The probe also determined that radiation in low-Mars orbit is twice that in low-Earth orbit (NASA JPL).</div></td></tr>
</table>SteigmeyerAhttps://microbewiki.kenyon.edu/index.php?title=Life_on_Mars&diff=64598&oldid=prevSteigmeyerA: /* Notable Mars Missions and Findings */2011-05-12T05:06:23Z<p><span dir="auto"><span class="autocomment">Notable Mars Missions and Findings</span></span></p>
<table style="background-color: #fff; color: #202122;" data-mw="interface">
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</tr><tr><td colspan="2" class="diff-lineno" id="mw-diff-left-l11">Line 11:</td>
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<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>[[Image:Mars Methane.jpg|thumb|300px|right|Fig. 2 Concentrations of methane observed on Mars by the Mars Express Orbiter. Credit: NASA.]]</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>[[Image:Mars Methane.jpg|thumb|300px|right|Fig. 2 Concentrations of methane observed on Mars by the Mars Express Orbiter. Credit: NASA.]]</div></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div><br><b>Viking 1 and 2</b> — Reached Martian surface on July 20, 1976 and September 1976, respectively. These landers were designed to analyze the Martian soil, atmosphere composition, weather and geographic features. The labeled-release experiment found that organic material was consumed when exposed to a soil sample, as if life were present. This contradicted a gas-chromatography experiment that yielded no evidence of organic compounds in the soil (Navarro-Gonzalez 2003). However, recent evidence suggests that these may have been low levels of organic compounds that the experiments were not sensitive enough to analyze, or that the organic compounds were too stable to be converted into a gas and thus were undetectable in the spectral analysis. (Handwerk 2006). </div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div><br><b>Viking 1 and 2</b> — Reached Martian surface on July 20, 1976 and September 1976, respectively. These landers were designed to analyze the Martian soil, atmosphere composition, weather and geographic features. The labeled-release experiment found that organic material was consumed when exposed to a soil sample, as if life were present. This contradicted a gas-chromatography experiment that yielded no evidence of organic compounds in the soil (Navarro-Gonzalez 2003). However, recent evidence suggests that these may have been low levels of organic compounds that the experiments were not sensitive enough to analyze, or that the organic compounds were too stable to be converted into a gas and thus were undetectable in the spectral analysis. (Handwerk 2006). </div></td></tr>
<tr><td class="diff-marker" data-marker="−"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div><br><br><b>Mars Global Surveyor </b> — Reached Mars orbit on September 12, 1997 and was operational through 2006. This orbiter was designed for extensive mapping of Mars and the study of daily weather patterns. It recorded images of gullies, debris flows and other evidence of surface water in Mars’ distant past as well as <del style="font-weight: bold; text-decoration: none;">CO2 </del>ice, which is slowly receding at the poles (NASA JPL). </div></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><br><br><b>Mars Global Surveyor </b> — Reached Mars orbit on September 12, 1997 and was operational through 2006. This orbiter was designed for extensive mapping of Mars and the study of daily weather patterns. It recorded images of gullies, debris flows and other evidence of surface water in Mars’ distant past as well as <ins style="font-weight: bold; text-decoration: none;">CO<sub>2</sub </ins>ice, which is slowly receding at the poles (NASA JPL). </div></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div><br><br><b>Mars Pathfinder </b>— The first successful lander since the Viking program, the rover Sojourner was designed to analyze the geological history of Mars, determine soil composition and look for signs of life. The landing site (Fig. 4) was selected because scientists believed that the area had once been the subjected to a large flood. The mission provided evidence suggesting that Mars had a warmer and wetter climate in the past (NASA JPL). </div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div><br><br><b>Mars Pathfinder </b>— The first successful lander since the Viking program, the rover Sojourner was designed to analyze the geological history of Mars, determine soil composition and look for signs of life. The landing site (Fig. 4) was selected because scientists believed that the area had once been the subjected to a large flood. The mission provided evidence suggesting that Mars had a warmer and wetter climate in the past (NASA JPL). </div></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div><br><br><b>Mars Odyssey </b>— The orbiter arrived at Mars on October 24, 2001 and conducted a planet-wide geological survey mission. It successfully mapped out mineral deposits across the planet and identified areas of water-ice just below the surface. The probe also determined that radiation in low-Mars orbit is twice that in low-Earth orbit (NASA JPL).</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div><br><br><b>Mars Odyssey </b>— The orbiter arrived at Mars on October 24, 2001 and conducted a planet-wide geological survey mission. It successfully mapped out mineral deposits across the planet and identified areas of water-ice just below the surface. The probe also determined that radiation in low-Mars orbit is twice that in low-Earth orbit (NASA JPL).</div></td></tr>
</table>SteigmeyerAhttps://microbewiki.kenyon.edu/index.php?title=Life_on_Mars&diff=64595&oldid=prevSteigmeyerA: /* Conclusions */2011-05-12T04:58:20Z<p><span dir="auto"><span class="autocomment">Conclusions</span></span></p>
<table style="background-color: #fff; color: #202122;" data-mw="interface">
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<td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">Revision as of 04:58, 12 May 2011</td>
</tr><tr><td colspan="2" class="diff-lineno" id="mw-diff-left-l54">Line 54:</td>
<td colspan="2" class="diff-lineno">Line 54:</td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div> Even with all the advantages of the dry waterways in the North, the organisms would still have to be adapted to several extreme conditions. The water in the soil micropores would be saline and extremely acidic. Although organisms exist in both types of environments on Earth (well within the range of Mars conditions), Martian microbes would have to be multi-faceted extremophiles. They would have to incorporate traits of halophiles, acidophiles, thermophiles, xerophiles and utilize anoxic and photosynthetic metabolism. It is not difficult finding an organism that exists under a couple of these environmental stresses, but can there be life so precisely evolved that it can survive in a highly specific niche? The answer can only come with time. <br><br></div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div> Even with all the advantages of the dry waterways in the North, the organisms would still have to be adapted to several extreme conditions. The water in the soil micropores would be saline and extremely acidic. Although organisms exist in both types of environments on Earth (well within the range of Mars conditions), Martian microbes would have to be multi-faceted extremophiles. They would have to incorporate traits of halophiles, acidophiles, thermophiles, xerophiles and utilize anoxic and photosynthetic metabolism. It is not difficult finding an organism that exists under a couple of these environmental stresses, but can there be life so precisely evolved that it can survive in a highly specific niche? The answer can only come with time. <br><br></div></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div> The early 21st Century has seen an unprecedented level of Mars exploration. Dozens of orbiters, robots and scientific instruments have been combing the planet for over a decade and we have learned more about Mars in that short time than in all of human history. Evidence for life on the Red Planet, past and/or present, is mounting. All we have to do is keep looking for this century’s little green men.<br><br><br></div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div> The early 21st Century has seen an unprecedented level of Mars exploration. Dozens of orbiters, robots and scientific instruments have been combing the planet for over a decade and we have learned more about Mars in that short time than in all of human history. Evidence for life on the Red Planet, past and/or present, is mounting. All we have to do is keep looking for this century’s little green men.<br><br><br></div></td></tr>
<tr><td class="diff-marker" data-marker="−"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>— August Steigmeyer</div></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>— August Steigmeyer<ins style="font-weight: bold; text-decoration: none;"><br><br></ins></div></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>==References==</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>==References==</div></td></tr>
</table>SteigmeyerAhttps://microbewiki.kenyon.edu/index.php?title=Life_on_Mars&diff=64594&oldid=prevSteigmeyerA: /* Conclusions */2011-05-12T04:57:36Z<p><span dir="auto"><span class="autocomment">Conclusions</span></span></p>
<table style="background-color: #fff; color: #202122;" data-mw="interface">
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<col class="diff-content" />
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<td colspan="2" style="background-color: #fff; color: #202122; text-align: center;">Revision as of 04:57, 12 May 2011</td>
</tr><tr><td colspan="2" class="diff-lineno" id="mw-diff-left-l53">Line 53:</td>
<td colspan="2" class="diff-lineno">Line 53:</td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div><br><br>If life is present on Mars, it will most likely be in microbial form. Living beneath the underground seems to be the only solution to the extreme desiccation, radiation and temperature effects on the surface. Based on the evidence shown here, the area of focus for future missions should be the saline deposits in regions just south of the North Pole. Not only are the soils in these regions rich in minerals, they also contain the highest percentage of water. The gypsum deposits in the dry lake and river beds could offer shelters from radiation and extreme temperature fluctuations, while allowing subsurface photosynthesis to occur. Gypsum and perchlorates could help pull gaseous water from the early morning mists and condense it in micropores within the soil. Microbes could thrive in the saline solutions formed in these halite-crust microhabitats. <br><br></div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div><br><br>If life is present on Mars, it will most likely be in microbial form. Living beneath the underground seems to be the only solution to the extreme desiccation, radiation and temperature effects on the surface. Based on the evidence shown here, the area of focus for future missions should be the saline deposits in regions just south of the North Pole. Not only are the soils in these regions rich in minerals, they also contain the highest percentage of water. The gypsum deposits in the dry lake and river beds could offer shelters from radiation and extreme temperature fluctuations, while allowing subsurface photosynthesis to occur. Gypsum and perchlorates could help pull gaseous water from the early morning mists and condense it in micropores within the soil. Microbes could thrive in the saline solutions formed in these halite-crust microhabitats. <br><br></div></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div> Even with all the advantages of the dry waterways in the North, the organisms would still have to be adapted to several extreme conditions. The water in the soil micropores would be saline and extremely acidic. Although organisms exist in both types of environments on Earth (well within the range of Mars conditions), Martian microbes would have to be multi-faceted extremophiles. They would have to incorporate traits of halophiles, acidophiles, thermophiles, xerophiles and utilize anoxic and photosynthetic metabolism. It is not difficult finding an organism that exists under a couple of these environmental stresses, but can there be life so precisely evolved that it can survive in a highly specific niche? The answer can only come with time. <br><br></div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div> Even with all the advantages of the dry waterways in the North, the organisms would still have to be adapted to several extreme conditions. The water in the soil micropores would be saline and extremely acidic. Although organisms exist in both types of environments on Earth (well within the range of Mars conditions), Martian microbes would have to be multi-faceted extremophiles. They would have to incorporate traits of halophiles, acidophiles, thermophiles, xerophiles and utilize anoxic and photosynthetic metabolism. It is not difficult finding an organism that exists under a couple of these environmental stresses, but can there be life so precisely evolved that it can survive in a highly specific niche? The answer can only come with time. <br><br></div></td></tr>
<tr><td class="diff-marker" data-marker="−"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div> The early 21st Century has seen an unprecedented level of Mars exploration. Dozens of orbiters, robots and scientific instruments have been combing the planet for over a decade and we have learned more about Mars in that short time than in all of human history. Evidence for life on the Red Planet, past and/or present, is mounting. All we have to do is keep looking for this century’s little green men.<del style="font-weight: bold; text-decoration: none;"><br></del><br><br><br></div></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div> The early 21st Century has seen an unprecedented level of Mars exploration. Dozens of orbiters, robots and scientific instruments have been combing the planet for over a decade and we have learned more about Mars in that short time than in all of human history. Evidence for life on the Red Planet, past and/or present, is mounting. All we have to do is keep looking for this century’s little green men.<br><br><br></div></td></tr>
<tr><td class="diff-marker" data-marker="−"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div> </div></td><td class="diff-marker" data-marker="+"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;">— </ins>August Steigmeyer</div></td></tr>
<tr><td class="diff-marker" data-marker="−"></td><td style="color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>August Steigmeyer</div></td><td colspan="2" class="diff-side-added"></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><br/></td></tr>
<tr><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>==References==</div></td><td class="diff-marker"></td><td style="background-color: #f8f9fa; color: #202122; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #eaecf0; vertical-align: top; white-space: pre-wrap;"><div>==References==</div></td></tr>
</table>SteigmeyerA