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Ancient and rare reefs discovered in British Columbia lake—Implications for Cambrian, extraterrestrial life


October 4, 2000: Scientists at Simon Fraser University in Vancouver, British Columbia, Canada, have discovered a unique form of reef growing in a B.C. lake, composed of mineral structures covered by microbial photosynthetic communities, that has attracted an investigative team from NASA. The discovery may help NASA identify life on Mars and elsewhere in space, because of the insight it gives into primitive lifeforms and the mineralization of microorganisms.

Pavilion Lake, located in a steep-walled limestone valley near Cache Creek, houses the so-called microbialites. The SFU group, headed by engineering science professor John Bird, designs and tests sonar tools that provide 3D underwater images of ocean and lake bottoms.

During tests in Pavilion Lake, researchers found many amazing coral-like cone-shaped growths of various sizes, up to three meters long. Samples were sent to McMaster University in Hamilton, Ontario for radioactive dating, where Derek Ford ascertained the crumbly light brown formations to be 11,000 years old, meaning they had begun forming shortly after glaciers receded from the area.

Samples were sent to NASA's Ames Research Lab in Mountain View California, prompting a pair of exobiologists, Sherry Cady and Chris McKay, to visit the site and collect more samples.

It appears these microbialites may be a modern analog for a class of lifeforms known as Epiphyton and Girvanella that formed massive reef belts in the early Cambrian era, 540 million years ago—the time during which most life first appeared on Earth.

The microbialites found in Pavilion Lake are composed of feathery calcite grains, covered by photosynthetic microbial communities (including cyanobacteria and diatoms) and their calcified remains. Such knowledge may help NASA exobiologists know what to look for when seeking fossilized remains and primitive communities on Mars and elsewhere.

Why do these structures grow in Pavilion Lake and not other similar lakes? Many questions remain unanswered, says Bird. It is also unclear whether the microbes form the calcium aggregates, or whether the rock crystallizes first, thereby attracting the organic life.

Bird says researchers want to see the lake become an environmentally protected zone. The Underwater Council of B.C. has applied to the provincial government for protection. Bird plans to continue a full-scale mapping of the lake bottom to help researchers better understand the structures and why they are there.



Links

The University of Glasgow reports possible remains of microbialites on Mars—includes photographs
http://www.gla.ac.uk/press/releases/originoflife.html

An image obtained by NASA's Mars Global Surveyor orbiter showing what appear to be microbialite-type mineral deposits
http://www.msss.com/moc_gallery/images/M0201994.html



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