Extreme extremophiles: antarctic midges (Introduction)

by David Turell @, Tuesday, September 10, 2019, 14:55 (9 days ago) @ David Turell
edited by David Turell, Tuesday, September 10, 2019, 15:04

Frozen a god part of the hear and survive:

https://www.nytimes.com/2019/09/09/science/antarctica-insects-midge-cold.html?nl=todays...

"...the Antarctic midge, is able to survive at the bottom of the planet. Purplish, wriggly and the size of a pinkie fingernail clipping, Antarctic midge larvae live for nearly two years underground, often near penguin and seal excrement. They spend over half of their lives, about eight months of the year, frozen.

***

"When the midge larvae are dehydrated, “they look like little raisins” said Rick Lee, a professor emeritus at Miami University in Ohio. “You can’t imagine that they’re alive. And then you drop them back into fresh water — they plump up and they wriggle away. I always say I think I can hear them laughing at us because they are so used to dealing with these stresses. They are super-tolerant.”

***

"So how does the Antarctic midge do it? Part of the answer lies in its microhabitat. Whereas the air temperature in Antarctica routinely drops below -20 degrees Celsius, the temperature beneath the soil and snowpack, where midge larvae live, is just a few degrees below zero.
When the midge larvae experience cold, the icy environment creates a gradient for water loss, extracting water from their bodies. Some larvae are able to lose enough water that they don’t freeze at all.

“'The wetter a site is, the more likely they’re going to freeze,” said Michael Elnitsky, a biologist at Mercyhurst University who wrote his dissertation on arthropods in Antarctica. Some midges live on islands with grainy, sandy soils that dry up. Others live in areas with moist moss beds. “In a more dry environment, they use the dehydration strategy to survive the winter,” he said.

"Another tool at the Antarctic midge’s disposal is rapid cold hardening. Insects and other coldblooded animals (think fish and toads) can quickly change their physiology when the temperature drops to boost their tolerance to cold.

"The exact mechanics of this process are still mysterious. There seem to be changes, though, at the level of individual cells. As the midge’s cells cool, some of their properties change, causing calcium to enter. Dr. Teets knows from past research that if calcium is prevented from entering cells, the organism is no longer able to perform rapid cold hardening. The calcium itself isn’t protective, but it functions like a switch that causes other important things to happen.

"Another tool at the Antarctic midge’s disposal is rapid cold hardening. Insects and other coldblooded animals (think fish and toads) can quickly change their physiology when the temperature drops to boost their tolerance to cold.

"The exact mechanics of this process are still mysterious. There seem to be changes, though, at the level of individual cells. As the midge’s cells cool, some of their properties change, causing calcium to enter. Dr. Teets knows from past research that if calcium is prevented from entering cells, the organism is no longer able to perform rapid cold hardening. The calcium itself isn’t protective, but it functions like a switch that causes other important things to happen."

Comment: It is always amazing to see how tenacious life can be. Many unanswered questions, such a how did the insect get there? Did it arrive in a warmer period and then gradually adapt? dhw will want to know about God's role. I assume adaptive instructions were provided.


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