The Curiosity rover has looked for methane on the Red Planet and has found none, disappointing hopes for finding life—Earth’s main source of methane—on Mars.
Researchers had good reasons to pin their hopes for Martian life on methane. On Earth, living things, such as methanogenic microbes, wetlands, and cattle, release vast quantities of the stuff. Researchers thought that any methane found on Mars might have come from a living thing, too. Plus, in Mars’ atmosphere, methane would dissipate quickly, so any that they did find was likely to be fresh and might even indicate that its Martian producer was still alive.
Ancient civilizations emitted greenhouse gasses, too; the red and orange dots above
mark indirect measures of methane in the atmosphere over the past two millennia.
Scientists have thought that humans only started emitting significant quantities of greenhouse gasses in the 19th century, after the Industrial Revolution—and the fossil fuels that powered it—took hold. But a study in Nature today suggests that our history as heavy emitters stretches back much farther, to the charcoal fires of the Roman Empire and the intensive agriculture of Han China.
To examine carbon emissions past, the research team analyzed more than 50 ice cores from Greenland, gauging levels of the greenhouse gas methane in Earth’s atmosphere going back to 100 B.C. They looked at specific carbon signatures in the methane to determine whether it came from burning coal and other materials—meaning humans might have been involved—or a natural biological process, then used mathematical models to further narrow down manmade emissions from naturally occurring ones. Human emissions, they found, were noticeable, though minuscule compared to post-industrial levels; only perhaps 10% human methane emissions over the past 2,000 years were produced before 1800. For a time when there were far fewer people around, however, that’s still a lot of methane to be sending off into the atmosphere.
What’s the News: Two hundred million years ago, half of the Earth’s species vanished in the blink of a geological eye, clearing the way for rise of the dinosaurs in the Jurassic. The cause of that mass extinction, a new study suggests, may have been gigatons of methane released from the sea floor after a slight rise in the earth’s temperature, triggering much greater warming. And if that sounds familiar, it’s because scientists are worried the same thing will happen today.
What’s the News: Astronomers have known for many years that Saturn’s moon Titan sports lakes of liquid methane. And in the past couple years, scientists have suggested that it also has an underground ocean composed of water and ammonia. Now, based on past observations by NASA’s Cassini spacecraft, astronomers are saying that Titan’s rotation indeed points to an underground sea—and where there’s water, there may also be life. “Our analysis strengthens the possibility that Titan has a subsurface ocean, but it does not prove it undoubtedly,” researcher Rose-Marie Baland told Astrobiology Magazine. “So there is still work to do.”
Oil wasn’t the only thing seeping into the Gulf of Mexico after the Deepwater Horizon disaster. The explosion of BP’s oil rig also triggered a leak a methane.
With the well unsealed, substantial amounts of the gas were released into the gulf. This plume of dissolved methane should have lurked in the water for years, hanging around like a massive planetary fart. But by August, it had disappeared. On three separate trips through the gulf, John Kessler from Texas A&M University couldn’t find any traces of the gas above background levels. He thinks he knows why – the methane was eaten by bacteria.
The gas pouring out of the broken well spurred the growth of bacteria called methanotrophs, which can break down methane as their only source of energy. They made short work of the gas. By the time that Kessler reached the gulf, just four months after the initial blowout, he found plenty of bacteria and precious little methane.
Check out the rest of Ed’s post on this discovery at Not Exactly Rocket Science.
As for BP itself: The petroleum giant now finds itself in the legal arena, but the company may avoid a worst-case scenario there. A presidential commission established to investigate the affair has found the brunt of liability to be BP’s, but also found the root cause of the disaster to be widespread, systematic mismanagement by everyone, and not rogue behavior by any one player. That is, BP will skate without being charged with “gross negligence” because everybody else made mistakes, too.
Commission co-chair William K Reilly said: “So a key question posed from the outset by this tragedy is, do we have a single company, BP, that blundered with fatal consequences, or a more pervasive problem of a complacent industry? Given the documented failings of both Transocean and Halliburton, both of which serve the offshore industry in virtually every ocean, I reluctantly conclude we have a system-wide problem.” [The Guardian]
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Image: U.S. Coast Guard
At this point, after finding microorganisms that don’t mind extreme temperatures, pressure, aridity and other hardships, we shouldn’t be surprised that bacteria‘s dominion over the Earth extends to just about anywhere we look. A new expedition to the Earth’s crust has reached unprecedented depths—down to the deepest layer of the crust—and found that even there, microorganisms are tough enough to survive.
On a hypothetical journey to the centre of the Earth starting at the sea floor, you would travel through sediment, a layer of basalt, and then hit the gabbroic layer, which lies directly above the mantle. Drilling expeditions have reached this layer before, but as the basalt is difficult to pierce it happens rarely. [New Scientist]
To circumvent the Herculean task of drilling through basalt, the expedition, called the Integrated Ocean Drilling Programme, headed out to sea to find an easier drilling location.
The Integrated Ocean Drilling Program sank its drill into the Atlantis Massif (seen above) in the central Atlantic Ocean where seismic forces have pushed the deep layer, known as the gabbroic layer, to within 230 feet of the ocean floor making it easier to reach. [UPI]
Japan doesn’t have much oil, leaving the island nation heavily depended upon imports. What it does have, though, is natural gas—far under the sea in methane hydrate formations. The country said this week that it is going after those deposits, drilling test wells next year with the intention of beginning extraction before the decade is out.
What makes methane hydrate unique is that it is a seemingly frozen and yet flammable material. Formed in cold, high-pressure environments, it is found throughout the world’s oceans as well as under the frozen ground of countries with high latitudes. While global estimates vary considerably, the U.S. Department of Energy says, the energy content of methane occurring in hydrate form is “immense, possibly exceeding the combined energy content of all other known fossil fuels.” [UPI]
No one has yet pursued hydrates in a major commercial way, so their enormous potential sits untapped. Japan succeeded with a test well in Canada two years ago, and now aims to test near its home shores.
Perhaps it’s a disservice to continue calling the oil pouring into the Gulf a spill. “Spill” makes it hard to conceptualize the estimated 60,000 barrels of oil per day blasting up from a well more than 5,000 feet below sea level. It also makes it difficult to picture how, as BP estimates, as much as 40 percent of the material “spilling” is methane gas. That methane has been largely overshadowed by the horror of oil-soaked pelicans and tar balls washing ashore, but now a survey, completed on Monday, has measured how the methane has spread.
What’s the problem with methane? The microbes that feed off it. It can create “methane seep ecosystems”–shallow food chains that eat crude oil and dissolved methane and in the process consume all available oxygen, leaving nothing for other marine life forms. Bacteria eat the methane and “ice worms” (so-called because they live around ice-like methane hydrate) eat bacteria, but nothing else eats these worms. This creates a “dead zone.”
So in short [an abundance of creatures that use] methane for food and oxygen to “breathe” will create areas where only bacteria and a few other non-life sustaining organisms can live. All others die. [San Francisco Chronicle]
If there were life on the Saturnian moon of Titan, the thinking goes, it would have to inhabit pools of methane or ethane at a cool -300 degrees Fahrenheit, and without the aid of water. While scientists don’t know just what that life would look like, they can predict what effects such tiny microbes would have on Titan’s atmosphere. That’s why researchers from the Cassini mission are excited now: They’ve found signatures that match those expectations. It’s far from proof of life on Titan, but it leaves the door wide open to the possibility.
In 2005, NASA’s Chris McKay put forth a possible scenario for life there: Critters could breathe the hydrogen gas that’s abundant on Titan, and consume a hydrocarbon called acetylene for energy. The first of two studies out recently, published in the journal Icarus, found that something—maybe life, but maybe something else—is using up the hydrogen that descends from Titan’s atmosphere to its surface:
“It’s as if you have a hose and you’re squirting hydrogen onto the ground, but it’s disappearing,” says Darrell Strobel, a Cassini interdisciplinary scientist based at Johns Hopkins University in Baltimore, Md., who authored a paper published in the journal Icarus [Popular Science].
Erring on the side of caution, the scientists suggest that life is but one explanation for this chemical oddity. Perhaps some unknown mineral on Titan acts as a catalyst to speed up the reaction of hydrogen and carbon to form methane, and that’s what accounts for the vanishing hydrogen. (Normally, the two wouldn’t combine fast enough under the cold conditions on Titan to account for the anomaly.) That would be pretty cool, though not as much of a jolt as Titanic life.