Algae Detoxifies Arsenic, Hints at Life on Other Planets

March 14, 2009 08:00 AM
by Haley A. Lovett
The discovery of algae that could rid the environment of arsenic strengthens the case for life elsewhere in the solar system.

Algae Detoxifies Arsenic in Yellowstone

Scientists in Yellowstone National Park have found a type of algae that can detoxify arsenic. In a paper published by the Proceedings of the National Academy of Sciences, scientists explain how the one-celled organism, called Cyanidioschyzon, can essentially turn arsenic into a less toxic form.

Arsenic is number one on a priority list of environmental poisons compiled by the U.S. Department of Health and Human Services. It is not safe for human consumption in drinking water at any more than 10 parts per billion and is best known as a tasteless poison, though it has other uses in mining and in some medical applications. Over time, arsenic in small doses can contribute to the development of cancer.
The scientists are hopeful that the discovery of Cyanidioschyzon will aid in the clean up of areas with high levels of arsenic, and with the creation of new types of food-bearing plants that traditionally have a high build up of arsenic, such as rice.  

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Alga Shows Possibility of Life in Extreme Conditions, Space

The newly discovered alga in Yellowstone lives in water up to 135 degrees Fahrenheit with an acidic pH factor of between 0.5 and 3.5. Tim McDermott, one of the authors of the paper, explained to Montana State University (MSU) News Service that the soil and water near the alga was so acidic that “it sometimes eats holes through his jeans when he kneels to collect samples.”

The alga was also able to survive the extreme UV radiation conditions of the basin where it was found.

Barry Rosen, one of the authors of the paper, says the discovery has shed light on how life survives extreme conditions. “If life can grow at high temperatures and high concentrations of heavy metals like arsenic,” he told the MSU News Service, “life might be able to evolve on other planets or moons such as Titan or Enceladus.”

Saturn’s moon Enceladus has long been looked at as a potential habitat for extra terrestrial life. In 2008, the spacecraft Cassini found carbon-based molecules in water vapor over Enceladus.

Related Topics: Other species in extreme environments; ‘water bears’ in space

The Yellowstone alga is not the only extreme environment where scientists have seen organisms survive. In 2007, New Scientist reported that microbes could survive tens of thousands of years in solid ice—not reproducing or thriving, but surviving within a tiny trace of liquid water with diffused gases as food. According to New Scientist, “The study bolsters the case that life may exist on distant, icy worlds in our own solar system.”

In 2007, the European Space Agency took tardigrades, also known as “water bears” into outer space. They found that many of the tiny animals (only about 1mm in length) were able to survive the extremely harsh vacuum of space—and exposure to deadly levels of solar UV radiation—without any shelter. The survivors of the trip were remarkably able to reproduce without trouble once returning to Earth.

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