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Marsbugs: The Electronic Astrobiology Newsletter, Volume 12, Number 26, 25 July 2005
Marsbugs: The Electronic Astrobiology Newsletter
Volume 12, Number 26, 25 July 2005
Editor/Publisher: David J. Thomas, Ph.D., Science Division, LyonCollege, Batesville, Arkansas72503-2317, USA.
Marsbugs is published on a weekly to monthly basis as warranted by the number of articles and announcements. Copyright of this compilation exists with the editor, but individual authors retain the copyright of specific articles. Opinions expressed in this newsletter are those of the authors, and are not necessarily endorsed by the editor or by LyonCollege. E-mail subscriptions are free, and may be obtained by contacting the editor. Information concerning the scope of this newsletter, subscription formats and availability of back-issues is available at The editor does not condone "spamming" of subscribers. Readers would appreciate it if others would not send unsolicited e-mail using the Marsbugs mailing lists. Persons who have information that may be of interest to subscribers of Marsbugs should send that information to the editor.
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Marsbugs: The Electronic Astrobiology Newsletter, Volume 12, Number 26, 25 July 2005
Articles and News
Page 1ANTARCTIC ECOSYSTEM DISCOVERED—NEW SPECIES OF MARINE LIFE MAY BE UNCOVERED
HamiltonCollege release
Page 2METHANE'S IMPACTS ON CLIMATE CHANGE MAY BE TWICE PREVIOUS ESTIMATES
By Krishna Ramanujan
Page 4ASTRONOMERS DEBATE WHETHER OLDEST KNOWN DUST DISK WILL EVER FORM PLANETS
Harvard-SmithsonianCenter for Astrophysics release 05-25
Page 5SPACE STATION HARVEST RELIEVES CREW'S MINDS, APPETITES
By Brad Amburn
Page 5PIGS IN SPACE
By Morris Jones
Page 5MELT THROUGH THE ICE TO FIND LIFE
From Universe Today
Page 5CYBORG ASTROBIOLOGIST COULD HELP ASTRONAUTS FIND LIFE ON MARS
By Larry Klaes
Page 5CHLOROPHYLL AND CLIMATE IN THE PACIFICOCEAN
NASA/GSFC release
Page 6INTERPLANETARY WHODUNIT—METHANE ON MARS
By David Tenenbaum
Page 7DUSTIEST STAR COULD HARBOR A YOUNG EARTH
Gemini Observatory release
Page 8SEEKING DEEP SPACE SALT LOVERS
By Rocco Mancinelli
Page 8NASA QUEST CHALLENGES STUDENTS TO STUDY MARS ON EARTH
NASA/ARC release 05-41AR
Page 9MARS HAS BEEN IN THE DEEP FREEZE FOR THE PAST FOUR BILLION YEARS, STUDY SHOWS
California Institute of Technology release
Page 9A TRIP TO MARS NEEDS WASTE
From SpaceDaily
Page 10SEARCHING FOR THE BIOLOGICAL OBJECTS ON MARS
By Alexander Zeltsman
Page 11METHANE ON EARTH—COMMON CHEMICAL, ELUSIVE QUARRY
By David Tenenbaum
Announcements
Page 12IMAGINE MARS: HUD NEIGHBORHOOD NETWORKS GET INVOLVED!
NASA/JPL webcast announcement
Mission Reports
Page 12CASSINI SIGNIFICANT EVENTS FOR 14-20 JULY 2005
NASA/JPL release
Page 14NASA ANNOUNCES DEEP IMPACT FUTURE MISSION STATUS
NASA release 05-193
Page 14MARS GLOBAL SURVEYOR IMAGES
NASA/JPL/MSSS release
Page 15MARS ODYSSEY THEMIS IMAGES
NASA/JPL/ASU release
Page 15NASA'S NEW MARS ORBITER WILL SHARPEN VISION OF EXPLORATION
NASA release 05-195
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Marsbugs: The Electronic Astrobiology Newsletter, Volume 12, Number 26, 25 July 2005
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Marsbugs: The Electronic Astrobiology Newsletter, Volume 12, Number 26, 25 July 2005
ANTARCTIC ECOSYSTEM DISCOVERED—NEW SPECIES OF MARINE LIFE MAY BE UNCOVERED
HamiltonCollege release
18 July 2005
The chance discovery of a vast ecosystem beneath the collapsed Larsen Ice Shelf will allow scientists to explore the uncharted life below Antarctica's floating ice shelves and further probe the origins of life in extreme environments. Researchers discovered the sunless habitat after reviewing a recent underwater video study examining a deep glacial trough in the northwestern Weddell Sea following the sudden Larsen B shelf collapse in 2002.
"This is definitely the biggest thing I've ever been involved with in the Antarctic," said Eugene Domack, a geosciences professor and lead author of the report detailing the ecosystem. The article will be published in the July 19 issue of Eos, the weekly newspaper of the American Geophysical Union. "Seeing these organisms on the ocean bottom—it's like lifting the carpet off the floor and finding a layer that you never knew was there."
Domack suggests the strong possibility that new species of marine life may be uncovered in continuing analyses of the area as ecosystem experts sample the site. The international expedition was there on a U.S. Antarctic Program cruise to study the sediment record in the area vacated by the former ice shelf. The crew recorded a video of the seafloor at the end of its mission and only later discovered a thriving clam community, mud volcanoes and a thin layer of bacterial mats.
View of cold-vent community under collapsed ice shelf.
The discovery was made during a trip to Antarctica this spring led by Domack to continue his ongoing investigation of the causes for the collapse of a massive ice sheet known as Larsen B. He was accompanied by a group of Hamilton undergraduate students along with students and professors from five other institutions including ColgateUniversity. Domack has taken more than 100 undergraduates to Antarctica since 1987. These expeditions are among the very few that include undergraduate student researchers.
This was the second year of a three-year multi-institutional, international effort that combines a variety of disciplines and integrates research with educational opportunities. In 2004, Domack was awarded $851,941 from the National Science Foundation Office of Polar Programs in support of these expeditions.
This discovery could provide evidence for researchers to better understand the dynamics within the inhospitable sub-ice setting, which covers more than 1.5 million square kilometers [nearly 580,000 square miles] of seafloor, or an area of the same magnitude to the Amazon basin in Brazil or the SaharaDesert. The ecosystem, known as a "cold-seep" (or cold-vent) community, is fed by chemical energy from within the Earth, unlike ecosystems that are driven by photosynthesis or hot emissions from the planet's crust. Domack and his coauthors propose that methane from deep underwater vents likely provide the energy source capable of sustaining the chemical life at the observed 850-meter [approximately 2800-foot] depth.
Such extreme cold-vent regions have previously been found near Monterey, California, where the phenomenon was discovered in 1984, in the Gulf of Mexico, and deep within the Sea of Japan. The recent report, however, presents the first finding of the type in the Antarctic, where the near-freezing water temperatures and almost completely uncharted territory will likely provide a baseline for researchers to probe portions of the ocean floor that have been undisturbed for nearly 10,000 years. The researchers speculate, for example, that the ice shelves themselves may have played a critical role in allowing the chemical habitat to thrive on the seafloor when it otherwise might not have established itself.
Domack noted, however, that the collapse of the Larsen B Shelf has opened the pristine chemical-based ecosystem to disturbances and debris that have already begun to bury the delicate mats and mollusks established within the underwater environment. He added that there may be a sense of urgency to investigate the unusual seafloor ecology below the Larsen shelf because of the likelihood of increased sediment deposition.
In addition, he suggests that the newfound system may provide incentive to launch studies to other remote undersea environments in the Poles and in other glacial settings such as LakeVostok, also in the Antarctic, to further explore the little-understood connection where ice sheets, the seafloor, and circulating water meet. The researchers indicate that the knowledge gained from any subsequent studies could enhance the examination of subterranean water on Earth or the hypothesized ocean beneath the surface on the Jovian moon Europa.
The research was supported by National Science Foundation grants to HamiltonCollege, ColgateUniversity, and Southern Illinois University.
Journal reference:
E. Domack et al., 2005. A chemotrophic ecosystem found beneath Antarctic ice shelf. Eos, 86(29):269-272,
Contact:
Vige Barrie
Phone: 315-859-4623
E-mail:
Read the original news release at
Additional articles on this subject are available at:
METHANE'S IMPACTS ON CLIMATE CHANGE MAY BE TWICE PREVIOUS ESTIMATES
By Krishna Ramanujan
NASA/GSFC release
18 July 2005
Scientists face difficult challenges in predicting and understanding how much our climate is changing. When it comes to gases that trap heat in our atmosphere, called greenhouse gases (GHGs), scientists typically look at how much of the gases exist in the atmosphere. However, Drew Shindell, a climatologist at NASA's Goddard Institute for Space Studies, New York, NY, believes we need to look at the GHGs when they are emitted at Earth's surface, instead of looking at the GHGs themselves after they have been mixed into the atmosphere.
Rice paddies in China. This image shows Chinese farmers transplanting rice in paddy fields in Yunnan Province, China, July 1999. Fossil fuels, cattle, landfills and rice paddies are the main human-related sources. Previous studies have shown that new rice harvesting techniques can significantly reduce methane emissions and increase yields. Image credit: Changsheng Li.
"The gas molecules undergo chemical changes and once they do, looking at them after they've mixed and changed in the atmosphere doesn't give an accurate picture of their effect," Shindell said. "For example, the amount of methane in the atmosphere is affected by pollutants that change methane's chemistry, and it doesn't reflect the effects of methane on other greenhouse gases," said Shindell, "so it's not directly related to emissions, which are what we set policies for."
Inland wetlands. Sources of methane include natural sources like wetlands, gas hydrates in the ocean floor, permafrost, termites, oceans, freshwater bodies, and non-wetland soils. Image credit: U.S. EPA, Leo Kenney, Region 1.
Chemically reactive GHGs include methane and ozone (carbon dioxide, the most important GHG, is largely unreactive). Once methane and the molecules that create ozone are released into the air by both natural and human-induced sources, these gases mix and react together, which transforms their compositions. When gases are altered, their contribution to the greenhouse warming effect also shifts. So, the true effect of a single GHG emission on climate becomes very hard to single out.
Some of the major investigations into the state of our warming planet come from a series of reports from the Intergovernmental Panel on Climate Change (IPCC) Assessment. These reports involved the work of hundreds of climate experts. The reports rely on measurements of greenhouse gases as they exist in the atmosphere, after they may have mixed with other gases. In other words, the findings in the report do not reflect thequantities that were actually emitted. Shindell finds there are advantages to measuring emissions of greenhouse gases and isolating their impacts, as opposed to analyzing them after they have mixed in the atmosphere. His study on the subject was recently published in the journal,Geophysical Research Letters. In the study, when the individual effects of each gas on global warming were added together, the total was within 10 percent of the impacts of all the gases mixed together. The small difference in the two amounts was a sign to Shindell that little error was introduced by separating the emissions from one another.
After isolating each greenhouse gas and calculating the impact of each emission on our climate with a computer model, Shindell and his colleagues found some striking differences in how much these gases contribute overall to climate change. The leading greenhouse gases include carbon dioxide, methane, nitrous oxide, and halocarbons. These gases are called 'well mixed' greenhouse gases because of their long lifetimes of a decade or more, which allows them to disperse evenly around the atmosphere. They are emitted from both man-made and natural sources. Ozone in the lower atmosphere, called tropospheric ozone, a major component of polluted air or smog that is damaging to human and ecosystem health, also has greenhouse warming effects. In the upper atmosphere, ozone protects life on Earth from the sun's harmful ultraviolet rays.
According to new calculations, the impacts of methane on climate warming may be double the standard amount attributed to the gas. The new interpretations reveal methane emissions may account for a third of the climate warming from well-mixed greenhouse gases between the 1750s and today. The IPCC report, which calculates methane's affects once it exists in the atmosphere, states that methane increases in our atmosphere account for only about one sixth of the total effect of well-mixed greenhouse gases on warming.
Methane in the world's atmosphere. These maps show the distribution of methane at the surface (top) and in the stratosphere (lower), calculated by a NASA computer model. Concentrations are shown in parts per million by volume. Methane is created near the surface, and it is carried into the stratosphere by rising air in the tropics. Image credits: GMAO Chemical Forecasts and GEOS–CHEM NRT Simulations for ICARTT (top) and NASA GSFC Atmospheric Chemistry and Dynamics Branch (lower).
Part of the reason the new calculations give a larger effect is that they include the sizeable impact of methane emissions on tropospheric ozone since the industrial revolution. Tropospheric ozone is not directly emitted, but is instead formed chemically from methane, other hydrocarbons, carbon monoxide and nitrogen oxides. The IPCC report includes the effects of tropospheric ozone increases on climate, but it is not attributed to particular sources. By categorizing the climate effects according to emissions, Shindell and colleagues found the total effects of methane emissions are substantially larger. In other words, the true source of some of the warming that is normally attributed to tropospheric ozone is really due to methane that leads to increased abundance of tropospheric ozone. According to the study, the effects of other pollutants were relatively minor. Nitrogen oxide emissions can even lead to cooling by fostering chemical reactions that destroy methane. This is partly why estimates based on the amount of methane in the atmosphere give the gas a smaller contribution to climate change.
Molecule for molecule, Methane is 20 times more potent than carbon dioxide as a greenhouse gas, but CO2 is much more abundant than methane and the predicted growth rate is far greater. Since 1750, methane concentrations in the atmosphere have more than doubled, though the rate of increase has slowed during the 1980-90s, and researchers don't understand why. Controlling methane could reap a big bang for the buck. Another bonus of this perspective is that in order to manage greenhouse gases, policy decisions must focus on cutting emissions, because that's where humans have some control.
"If we control methane, which the U.S. is already starting to do, then we are likely to mitigate global warming more than one would have thought, so that's a very positive outcome," Shindell said. "Control of methane emissions turns out to be a more powerful lever to control global warming than would be anticipated."
Sources of methane include natural sources like wetlands, gas hydrates in the ocean floor, permafrost, termites, oceans, freshwater bodies, and non-wetland soils. Fossil fuels, cattle, landfills and rice paddies are the main human-related sources. Previous studies have shown that new rice harvesting techniques can significantly reduce methane emissions and increase yields.
Journal reference:
D. T. Shindell et al., 2005. An emissions-based view of climate forcing by methane and tropospheric ozone. Geophysical Research Letters, 32:L04803,
Read the original news release at
An additional article on this subject is available at
ASTRONOMERS DEBATE WHETHER OLDEST KNOWN DUST DISK WILL EVER FORM PLANETS
Harvard-SmithsonianCenter for Astrophysics release 05-25
18 July 2005
Every rule has an exception. One rule in astronomy, supported by considerable evidence, states that dust disks around newborn stars disappear in a few million years. Most likely, they vanish because the material has collected into full-sized planets. Astronomers have discovered the first exception to this rule—a 25-million-year-old dust disk that shows no evidence of planet formation.
"Finding this disk is as unexpected as locating a 200-year-old person," said astronomer Lee Hartmann of the Harvard-Smithsonian Center for Astrophysics (CfA), lead author on the paper announcing the find.
Astronomers were surprised to discover a 25-million-year-old protoplanetary disk around a pair of red dwarf stars 350 light-years away. Gravitational stirring by the binary star system (shown in this artist's conception) may have prevented planet formation. Image credit: David A. Aguilar (CfA).
The discovery raises the puzzling question of why this disk has not formed planets despite its advanced age. Most protoplanetary disks last only a few million years, while the oldest previously known disks have ages of about 10 million years.
"We don't know why this disk has lasted so long, because we don't know what makes the planetary formation process start," said co-author Nuria Calvet of CfA.
The disk in question orbits a pair of red dwarf stars in the Stephenson 34 system, located approximately 350 light-years away in the constellation Taurus. Data from NASA's Spitzer Space Telescope shows that its inner edge is located about 65 million miles from the binary stars. The disk extends to a distance of at least 650 million miles. Additional material may orbit farther out where temperatures are too low for Spitzer to detect it.
Astronomers estimate the newfound disk to be about 25 million years old. They calculated the age by modeling the central stars within the system, since stars and disk share the same age. The appearance of the disk itself also supports an advanced age.