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Glaciers. Conjures up visions of gigantic structures — lifeless and immovable. But actually they are teeming with life. Microbial organisms — of an amazing variety — thrive and grow in glaciers. This is the story one of these. Cyanobacteria or blue-green algae are single-celled organisms. They are visible when they grow in ‘colonies’ and are found in Himalayan, Alaskan and Arctic glaciers.

They rank among the oldest of fossils found on earth and have played a major role in the evolution and ecological changes on our planet. Heard of chloroplast with which plants make their food? This is actually a cyanobacterium living in plants’ cells…

But now these little heroes are being labelled as villain number one. Why? Because they have been found guilty of contributing to that dreaded phenomenon —global warming. Here is how they do it.

 

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Albedo in algae — triggering global warming?
You must have read about rising global temperatures and of climate change, that have created panic amongst the scientists across the world. According to them, carbon particles, a dusty by-product of incomplete combustion of fossil fuels has been responsible for 25 per cent rise in global temperatures since 1880. The dark soot found on glaciers is nothing but the "dark coloured" bacteria that we are talking about.

The cyanobacteria grow on the ice by trapping organic materials like carbon dioxide, and a dark-coloured algal mat is formed. This drills holes into the glacier, by melting it. Glaciers are normally not nutrient-rich. But these holes provide an aquatic habitat for the algae and bacteria living on them.

Glaciers reflect sunlight back into the atmosphere and remain immune to the heat. The algal mat covering the Himalayan and Alaskan glaciers reduces surface albedo — that is, the capacity of the glacier to reflect radiation or sunlight. Result? The snow melts at a much faster rate…and the glacier dissolves slowly but steadily.

Glacier Dwellers

Snow fleas/ glacier fleas:
Insects about the size of the head of a pin. They feed on algae and conifer pollen.

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Ice worms:
Relatives of the earthworm, but much smaller. Live in temperatures below freezing point. Squeeze themselves between ice crystals. Eat algae.

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Red algae:
Its red colour sometimes prompts people to call it "watermelon snow." Found on temperate glaciers and permanent snow. Makes its own food through photosynthesis. Grows in summers. Large areas of snow look red or pinkish because of all the red algae on them.

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Snow algae:
Found on North Pole. Recently discovered, provides a vital clue to patter of evolution in the glaciers.

 

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