Tuesday, April 10, 2012

Psychrophiles In Watermelon Snow

The first accounts of watermelon snow are in the writings of Aristotle. Watermelon snow has puzzled mountain climbers, explorers, and naturalists for thousands of years, some speculating that it was caused by mineral deposits or oxidation products that were leached from rocks.

In watermelon sugar the deeds were done and done again as my life is done in watermelon sugar. I'll tell you about it because I am here and you are distant.

Richard Brautigan
those are the opening sentences
of his short novel,
In Watermelon Sugar

Nature, so they say, abhors a vacuum.
I’ve always wondered why evolution
didn’t chance upon a mechanism
comfortable in the winter’s cold dark
as insects are on a summer’s warm night.

There’s a lot going on around here, and I am getting a little backed up. I don’t have as much prepared for today as I would like, but I’ve got this business about psychrophiles. I hope it’s better than nothing. At some point in the near future I hope to have some stuff that’s pretty interesting. But, like I said, I’m getting a little behind trying to keep up with the real world.

Anyway today is about psychrophiles.

They cause watermelon snow.

Up until a few days I had never heard of psychrophiles. And even though Wikipedia says Aristotle wrote about watermelon snow, I had never heard of that, either.

(I don’t know if Brautigan was making an allusion to watermelon snow with his phrase ‘watermelon sugar.’ Since references to watermelon snow date back to Aristotle, it wouldn’t surprise me at all to learn that Brautigan was thinking about it. It never occurred to me for years that the title “Sombrero Fallout” could be a very cool allusion to a thing called a sombrero filter—because of the way violence spreads out, and the author’s sadness spreads out, in the novel—but once I learned that Brautigan spent time as poet-in-residence at MIT it occurred to me that his word-centric mind may very well have squirreled away all manner of cool science allusions. I don’t know, but it’s possible. Good writers do that kind of thing. Or try to.)

Anyway, again, as I wrote in my post “More Night Than Just The Stars,” it’s always seemed strange to me that when you set up a telescope on a summer night you are almost immediately a focus of insect interest and migration. Insects love amateur astronomers. But on winter nights there is nothing but cold air.

So far as we know.

It just seems strange. So I’m always noticing little things about life forms that like strange environments and a few days ago (in connection to some of the real background of “Waiting For Clouds”) I saw the word “psychrophiles.”

Psychrophiles or cryophiles (adj. cryophilic) are extremophilic organisms that are capable of growth and reproduction in cold temperatures, ranging from −15°C to +10°C. Temperatures as low as −15°C are found in pockets of very salty water (brine) surrounded by sea ice. They can be contrasted with thermophiles, which thrive at unusually hot temperatures. The environments they inhabit are ubiquitous on Earth, as a large fraction of our planetary surface experiences temperatures lower than 15°C. They are present in alpine and arctic soils, high-latitude and deep ocean waters, polar ice, glaciers, and snowfields. They are of particular interest to astrobiology, the field dedicated to the formulation of theory about the possibility of extraterrestrial life, and to geomicrobiology, the study of microbes active in geochemical processes. In experimental work at University of Alaska Fairbanks, a 1000 litre biogas digester using psychrophiles harvested from "mud from a frozen lake in Alaska" has produced 200–300 litres of methane per day, about 20–30 % of the output from digesters in warmer climates.

Psychrophiles use a wide variety of metabolic pathways, including photosynthesis, chemoautotrophy (also sometimes known as lithotrophy), and heterotrophy, and form robust, diverse communities. Most psychrophiles are bacteria or archaea, and psychrophily is present in widely diverse microbial lineages within those broad groups. Additionally, recent research has discovered novel groups of psychrophilic fungi living in oxygen-poor areas under alpine snowfields. A further group of eukaryotic cold-adapted organisms are snow algae, which can cause watermelon snow. Psychrophiles are characterized by lipid cell membranes chemically resistant to the stiffening caused by extreme cold, and often create protein 'antifreezes' to keep their internal space liquid and protect their DNA even in temperatures below water's freezing point.

I learned that there are organisms that thrive in the cold. And so it seems even more strange, then, that there are no insect-sized organisms with similar adaptations makings pests of themselves on winter nights.

So that’s one of the things that’s been going on around here. I’ve been learning about organisms that like the cold, metabolisms that work well in the cold, and wondering more about why astronomers out on cold winter nights are free from pests. It’s an old question for me, and it has gotten more interesting now that I’ve learned about psychrophiles.

And that’s all I’ve got for today. A lot is happening around here, and I’ll try to get more of it on the blog. If I can.

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