Green ice, Ravens, Ice Caves and the Movie “Contact”

Towards the end of our summer expedition while flying back to Eureka from our camp on Axel Heiberg, I spotted a lake with what appeared to be green ice on it.

Seeing ice this color is particularly interesting since the color green tends to make an aquatic ecologist think of life – microbial life with chlorophyll. It also reminded me of a question I first heard posed by Chris McKay, a scientist at NASA’s Ames Research Center in California. During one of his presentations, Chris asked the question “why isn’t Greenland green? Why is the ice-cap of Greenland, or the Antarctic for that matter, not covered with photosynthetic organisms tinting the snow and ice green despite the abundant availability of summer sun and 90% of the planet’s fresh water?”

This observation points out a profound ecological reality for life on Earth – just having water available is not enough – it must be liquid water in order for life to carry out the chemistry of life. The snow and ice on the ice-caps do not support an abundance of photosynthesizers mainly because the water is present as a solid (ice) and for all practical purposes is not available for life to use. Despite the cubic kilometers of water within these ice-caps, they are vast frozen deserts. I did not have time to drop down to get a sample of the bright green ice, but as green as it was, I suspect that the tint must have been a result of the presence of chlorophyll. The difference between this lake ice and the ice-caps of Greenland and Antarctica being the abundance of liquid water on and within the small ice-cover as it melted away.

This full story is online at Astrobiology.net