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 Nordic Special

Through a Glass Darkly
Organisms colonize glass in order to extract energy, “eating” metals such as iron or manganese contained within.
By Leslie Mullen

Plucking Daisyworld
On the hypothetical planet Daisyworld, flowers control the climate. Black daisies absorb sunlight and warm the planet.
By Leslie Mullen

Seeing Life in Viruses
We all try to avoid viruses due to the havoc they can wage on our health. Some viruses do more than create temporary discomfort.
By Leslie Mullen

Iceland Brings Astrobiology Down to Earth
If you want to learn about the role of water on Mars and Europa, Iceland is a good place to start.
By Simon Mitton

Mini-Sub for Tight Spaces
The water locked underneath icecaps or glaciers can tell us about our planet's past and its possibly warmer future. Similar environments on distant worlds could tell us whether life can originate in these harsh conditions. To study the icy depths, a Swedish team of researchers is designing a tiny submersible that can slip down a narrow borehole.
By Michael Schirber


Iceland Brings Astrobiology Down to Earth

By Simon Mitton

If you want to learn about the role of water on Mars and Europa, Iceland is a good place to start. This land of fire and ice provides many examples of glaciers and melt water in circumstances that might exist on other rocky planets or moons in the solar system.

Water is the medium in which the chemistry of life on Earth takes place, and the habitat within which life emerged. Understanding how water relates to the origin of life is an important goal for astrobiology.

Europa, the fourth largest moon of Jupiter, is encased in a thick coating of water ice thought to be up to 30 miles (45 km) thick.  Planetary scientists have long believed an ocean lies beneath Europa’s ice cover. This hidden ocean is warmed by the energy of tidal forces generated by Jupiter’s massive gravitational influence. Much as scientists would like to send a lander to Europa to sample its ocean, the reality is that such a bold mission lies decades in the future.

Meanwhile, astrobiologists are investigating microbial life in lakes beneath ice sheets on Earth, such as the many subglacial lakes beneath the frozen wastes of Antarctica. The largest, Lake Vostok, is as large as Lake Ontario, and it is a prime target for future investigations of microbial life that may have evolved in isolation for millions of years. Drilling into Antarctic lakes has not been accomplished yet, but the subglacial lakes of Iceland are accessible.  These Icelandic lakes may provide insight into the potential for life in Antarctica and perhaps even Europa.

subglacial lake

The subglacial lakes of Iceland can serve as test beds for science and technology to be used on future planetary missions. This field camp is drilling for microbial life 1000 feet (300 m) below the ice.

Thorsteinn Thorsteinsson, a glaciologist with the Hydrology Division of Iceland’s National Energy Authority, has led studies of Icelandic subglacial lakes in recent years.  These lakes form where volcanic hot-spots from below partially melt the overlying ice cap. Since such lakes typically have been isolated from the rest of the environment, astrobiologists are interested to discover whether life can flourish there. Sunlight can penetrate no more than 300 feet (100 m) of ice, so life in such environments relies on chemical sources of energy.

In 2002, Icelandic and US scientists drilled through 1,000 feet (300 m) of the ice shelf of the largest and best known of these lakes, Lake Grímsvötn. The researchers obtained samples for the first microbiology study of lake waters. Although the Icelandic lakes are not thought to be pristine systems like Lake Vostok, Thorsteinsson’s team developed a hot water drilling system complete with water sterilization to guard against contamination.

Drilling For Samples

A hot-water sampler used to extract uncontaminated samples of water from the lake 1000 feet below. The presence of viable microbial communities in these concealed lakes suggests that the buried ocean on Europa in an important target for a future astrobiology mission.

The scientists discovered that the water and sediments of Lake Grímsvötn are home to viable microbial communities that tolerate the low-temperature and nutrient-poor conditions in the lake. Their DNA is different to that of microbes in the overlying ice and snow. Thorsteinsson speculates that the seed organisms are transported by wind and then are dumped on the ice cap.  At first these organisms become entombed in the glacier, but when the base of the ice that lies above the lake melts, the microbes are released and can colonize the lake.

Iceland is an obvious analog for questions about the possibility of life on Europa, but it also has tales to tell us about the role of water on Mars. Thorsteinsson explored this issue with William K. Hartmann of the Planetary Science Institute in Tucson, Arizona. Their research compared Icelandic hillside gullies with those on Mars.

Jupiter's moon - Europa

Jupiter's moon Europa has a global ocean of salty water beneath a frozen outer layer of ice. Scientists hope to someday investigate Europa's ice and the ocean that lies beneath to see if life exists there.

Many scientists believe the martian gullies formed by water emerging from subsurface aquifers. Although the Icelandic gullies are formed from surface run-off, not aquifers, at least some of the water-based debris flow systems in Iceland are similar in appearance to the martian gullies.  This supports, but does not prove, the hypothesis that martian gully systems are created by water-based, geologically recent flood erosion on Mars.

NASA's Mars Exploration Program has adopted “Follow the Water” as its strategy, and the specific goals include looking for hot springs, hydrothermal vents or subsurface water reserves. The interest of the scientific community in these and other phenomena has made Iceland a common venue for symposia in recent years. In 2009, Nordic and US scientists are planning an international summer school on the theme “Water, Ice and the Evolution of Life in the Universe,” to be held in Reykjavik, where NASA researchers and their Nordic colleagues will be training future astrobiologists.

 

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