Friday, December 7, 2012

Life thrives in one of Earth's most extreme environments

Lake Vida in the McMurdo Dry Valleys, in East Antarctica
Here's another story about an ice-entombed Antarctic lake, which I found in New Scientist, 26 November.

It's Lake Vida in East Antarctica, which has been buried for 2,800 years under 20 metres of ice.  (But no snow ... weird ... I never knew Antarctica looked like this.)  Those figures are negligible compared to much older, deeper lakes under investigation in Antarctica, most notably lakes Vostok and Ellsworth, which I wrote about a couple of days ago.  Those are 3 kilometres down and may have been isolated for millions rather than thousands of years. 

But here's the interesting bit.
Lake Vida is one of the most extreme environments on Earth. It's seven times as salty as the sea, pitch dark, and 13 degrees below freezing, yet despite all this it teems with life.

We were pondering the chance that extraterrestrial life might exist on planets such as Mars, or icy moons such as Jupiter's Europa.
The discovery of strange, abundant bacteria in a completely sealed, sunless, salty, icebound lake must strengthen this possibility.

New Scientist quotes Peter Doran of the University of Illinois saying "Lake Vida is a model of what happens when you try to freeze a lake solid, and this is the same fate that any lakes on Mars would have gone through as the planet turned colder from a watery past.  Any Martian water bodies that did form would have gone through this Vida stage before freezing solid, entombing the evidence of the past ecosystem."  Doran is co-leader of a team working in the Dry Valleys of Antarctica where Vida is situated.

Energy from
chemicals not sunlight?

The Vida bacteria belong to previously unknown species. It's thought they probably survive by metabolising the abundant hydrogen and oxides of nitrogen that Vida's salty, oxygen-free water has been found to contain. It seems researchers were surprised to find such high concentrations of hydrogen, nitrous oxide and carbon in the water. They speculate that these chemicals might originate from reactions between salt and nitrogen-containing minerals in the surrounding rock. Over the centuries, bacteria denied sunlight may have evolved to be completely reliant on these chemicals for energy.

Some of the extracted cells are being grown in a lab, in order to better understand the physical or chemical extremes they can tolerate.  

Here's how the researchers think the lake got so salty. As the top and edges of the lake progressively froze, all the salt became concentrated in the remaining water, which as a result can stay liquid below -13 °C.

More on US Antarctic Programme website.

There are other extreme environments on Earth where life thrives. Beside hot deep ocean vents, for example. But more of them another day perhaps.

Wednesday, December 5, 2012

I find an optimistic comment about pharao Morsi

President Morsi - “pharaonic” decree
Haven't said anything abut the Arab Spring recently because I'm a bit down in the mouth about the whole thing. But for a dose of optimism, read Mehdi Hasan in the New Statesman, on 29 November.  

Hasan says we should ignore the neocons, he refuses to give up on Egypt, or the Arab spring.  Despite the murmurs about Morsi’s “pharaonic” decree and the Syrian bloodbath, he refuses to lose faith in the people of the Arab world.  For a start, we should all be celebrating the backlash against Morsi’s decree and how instant it was.

One point I need to take issue with him though.

Pointing out that revolutions are measured in years and decades, not weeks and months, he quotes Chinese premier Zhou Enlai’s remark “It is too soon to say” made in 1971, when asked for his view on the success of the French Revolution of 1789.

That one, sad to say, has been nailed.

Tuesday, December 4, 2012

Manhattan Project: Celebrating? Or commemorating?

A Quonset hut on the grounds of the Los Alamos National Lab in New Mexico where "Fat Man" (atomic bomb dropped on Nagasaki on Aug. 9, 1945) was assembled. The hut would be part of a new Manhattan Project National Park.

Historical photograph courtesy of Los Alamos National Laboratory. I'm not sure if this caption means this was the actual hut, or just one like it.
A US congressman has condemned a bill to make a national park out of three top-secret sites which housed the Manhattan Project.

"We're talking about the devastation of the people of Hiroshima and Nagasaki — hundreds of thousands killed, $10 trillion Cold War between the U.S. and Russia, tens of thousands of nuclear weapons which today threaten the existence of the world — and this is something we should celebrate?"

The words of Democrat congressman Dennis Kucinich (Ohio), reported by NPR.

The contrary position is put by director of the Los Alamos Historical Society, Heather McClenahan. A park would be a commemoration, not a celebration. And the US already has national parks commemorating slavery, Civil War battles and American Indian massacres.

"It's a chance to say, 'Why did we do this? What were the good things that happened? What were the bad? How do we learn lessons from the past? How do we not ever have to use an atomic bomb in warfare again?' "

That’s history.

Read it on the NPR website where you can also download an audio clip, 3 min 38 sec.

The congressman and the history woman are both right of course.  But of the two, the history woman is the righter.

Extraterrestrial life? Keep your eye on Lake Ellsworth

The sun is shining night and day in the Antarctic right now, but the temperatures remain far below freezing. Photograph: British Antarctic Survey
A search for life is beginning in a lake entombed under Antarctic ice. Lake Ellsworth is buried under three kilometres of solid ice, and is the size of Lake Windermere. Keep an eye on this story. A drilling operation is now reaching its climax and the actual lake water ought to be reached between 12th and 15th December. 

Here's why it's important. Should life be found lurking in the depths, it will have evolved in isolation for at least 100,000 years, but probably much longer. I've seen millions mentioned. Scientists want to know whether life can endure such harsh environments. If it can, the next question is how. Any organisms that live here are cut off from the air above, and must contend with subzero conditions, few nutrients, complete darkness, and intense pressure.

The answers will further our understanding of life on Earth, and inform searches for life elsewhere in the solar system, such as in the ice-capped ocean of Jupiter's moon Europa.

Mike Bentley, a geologist, was quoted in yesterday’s Guardian: "Extreme environments tell you what constraints there are on life. If we find a particular set of environments where life can't exist, that creates some bookends: it tells you about the limits of life."

Another buried Antarctic lake, Lake Vostok, is being probed by Russian scientists. It's even deeper and more challenging, and the project has been criticised due to concerns that the Russians may contaminate the lake with microbes from the surface that would nullify any discovery of life there. The British team will use a sterile hot water drill to bore down. According to Nature,  this method would be impractical at Lake Vostok due to the thicker glacier.

New Scientist reported in October that no sign of life has been discovered in the first Lake Vostok samples but microbes may lurk deeper in the lake.

The more life is found in buried Antarctic lakes the better the prospects for life on Jupiter's icy moon Europa.

Beneath Europa's icy shell, it is thought a liquid ocean exists, potentially supporting complex organisms
I need to check what missions are planned to Europa and Jupiter's other icy moons.  ESA has or had a project known as JUICE - the Jupiter Icy moons Explorer, to be launched in 2022. And NASA has the Europa Jupiter System Mission (EJSM). But I have a feeling one or other of these has been cancelled or they have been merged or something. Who knows what damage austerity will do between now and 2022. 

For more see this Guardian link: British Antarctic Survey in pictures

Isolated for millions of years

One thing puzzles me in all the commentary on these Antarctic lakes. That’s the emphasis on their being isolated from all other life for perhaps millions of years. Even if this turns out to be so, millions of years doesn't strike me as long enough to be interesting. Some comments on this theme in a post I wrote about Lake Vostok in February 2011.