Antarctica's extreme salt-loving microbes like to swap DNA

UNSW

Deep Lake in Antarctica is so salty that it stays liquid at temperatures down to minus 20 degrees Celsius (minus 4 degrees Fahrenheit).

Microbes living in Antarctica's saltiest lake swap huge chunks of genetic material as a means of surviving their harsh environment, a new study finds.

The single-celled organisms, called haloarchaea for their salt-loving ways, are biologically distinct from bacteria, algae and other tiny creatures that can thrive in extreme settings.

Their Antarctic home is a deep lake in the Vestfold Hills severed from the ocean more than 3,000 years ago. Appropriately named Deep Lake, the basin sits 50 meters (165 feet) below sea level. Deep Lake is so salty that it's never been known to freeze, even at temperatures below minus 4 degrees Fahrenheit (minus 20 degrees Celsius).

Little else lives in Deep Lake except haloarchaea. For years, scientists have been analyzing the microbes to see what makes them thrive in the strange environment, and for clues to possible life on other planets. [Life on Ice: Gallery of Cold-Loving Creatures]

One unusual survival technique has now been found: The handful of haloarchaea species in Deep Lake exchange DNA, according to a study published Monday in the journal Proceedings of the National Academy of Sciences.

Though each species is specialized and has its own niche, such as eating proteins or sugars, they come together and trade chunks of DNA, some as long as 35,000 letters of code, a team led by Rick Cavicchioli, a microbiologist at the University of New South Wales in Australia, discovered.

"Our research shows these (haloarchaea) swap much more genetic material with each other than has been observed in the natural environment before. Long stretches of virtually identical DNA are exchanged between different genera, not just species," Cavicchioli said in a statement. "Despite this rampant gene swapping, the different species are maintained and can co-exist because they have evolved to exploit different niches and consume different food sources." (Genus is the classification above species.)

Another consequence of life in the cold zone is slowed reproduction. The lake haloarchaea reproduce only six times a year, the researchers found.

Cold-loving extremophiles also live in permafrost, or permanently frozen ground, and in lakes buried beneath Antarctica's ice sheet. Microbes also happily make their home within the ice sheet itself.

Email Becky Oskin or follow her @beckyoskin. Follow us @livescience, Facebook and Google+. Original article on LiveScience.com.

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• The Coldest Places on Earth
• Strangest Places Where Life Is Found on Earth

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UFO over Indian Ocean? SpaceX Falcon 9 rocket sparks sightings

Alan Boyle, Science Editor NBC News    

SpaceX's first-ever Falcon 9 launch from California gave a big boost to commercial spaceflight — but it also boosted our planet's store of UFO lore.

Reports about a fuzzy-looking unidentified flying object streamed in from observers in southern Africa and the Indian Ocean islands of Mauritius and Reunion. The sightings came about an hour after the Falcon 9 v1.1 rocket's launch from Vandenberg Air Force Base at 9 a.m. PT (noon ET) Sunday.

The Zimbabwe Mail marveled over the "strange moonlike object" seen from the country's Mashonaland region, as well as from Botswana, Malawi and South Africa. Mauritius' L'Express wondered whether it was a UFO, a satellite or a star cluster.

A retired astronomer from Cape Town, Greg Roberts, gave the correct explanation in an interview with The New Age, a South African publication: "It was propellant or rocket fuel" released by the Falcon 9 rocket's second stage.

After sending several satellites into a pole-to-pole orbit, the Falcon's second stage released its leftover fuel, which is standard procedure to avoid a blowup during its atmospheric re-entry.

"This release by chance coincided with sunset beneath that part of the orbit, as the booster and its deployed satellites flew from south to north directly over Madagascar, about 850 miles high," NBC News space analyst James Oberg explained in an email. Sunlight set the cloud of rocket fuel aglow.

In a Tumblr post, rocket scientist Ben Brockert speculated that the fuel release might be related to a reported anomaly in the attempted restart of the second-stage rocket engine. Reddit has more chatter about the rocket report.

This sort of phenomenon has been seen many times before — and the bottom line is that you can expect an uptick in UFO reports anytime there's a rocket launch, particularly when the rocket is blazing a new trail, like this brand-new breed of Falcon.

More rocket UFO reports:

• Chinese UFO linked to European rocket
  
• Middle East UFO linked to Russian missile test
  
• 2010: SpaceX launch sparks UFO reports in Australia
  
• NBC News archive on UFOs
  

Tip o' the Log to James Oberg.

Alan Boyle is NBCNews.com's science editor. Connect with the Cosmic Log community by "liking" the NBC News Science Facebook page, following @b0yle on Twitter and adding +Alan Boyle to your Google+ circles. To keep up with NBCNews.com's stories about science and space, sign up for the Tech & Science newsletter, delivered to your email in-box every weekday. You can also check out "The Case for Pluto," my book about the controversial dwarf planet and the search for new worlds.