8/18/07

Why is the snow pink?

Up in Whistler, Shawn and Wendy didn't know what the pink snow was all about. All Wendy knew was that she had been warned not to eat yellow or pink snow. She thought it caused diarrhea (which the literature seems to support).

Pink snow, sometimes called "watermelon snow," happens during the early spring and summer months where there is still snowpack. It's a phenomenon dating way back in recorded history. In fact, Aristotle mentioned it in some of his writings! I'm not sure why it took so long to identify the cause of it, but at the end of the nineteenth century, the mystery was solved- pink snow comes from microscopic algae. More than sixty different species of snow algae have been identified in the western US mountain ranges, but Chlamydomonas nivalis is responsible for the pink snow. (ironically, it's a member of the green algae Division). Because it's an algae, it has chlorophyll, but C. nivalis also has a carotenoid pigment that gives it the red color. The carotenoid pigment is similar to the ones in tomatoes, red peppers, colorful flowers, seafood exoskeletons, corals, egg yolks, fish/amphibian skin, and fall leaves. They can also be orange, yellow, or yellow-green.

C. nivalis (nivalis means "snow" in Latin) is thought to go dormant when covered by deep layers of snow and then germinate when meltwater brings down nutrients, but scientists aren't exactly sure how the germinated cells then release smaller green cells that flagellate to the surface of the snow to turn pink. Sometimes you see depressions in the snowbanks that are especially red; these are called "sun cups." The red pigmentation absorbs heat, causing the snow to melt faster and cause the depression.


Picture credit here.

Picture credit here.

Word to the wise inquiring minds: this search brought up some questionable sites!

Special thanks:

When does fireweed bloom?

Fireweed gets its name because of how earnestly it colonizes land after a forest fire. It's also being used to reestablish vegetation on sites that have been disturbed by oil spills! Basically all it needs to grow and flower is lots of space and lots of light. When other plants begin to grow in the burned land, fireweed can't compete and becomes much less abundant. But it's a scrappy plant- seeds can remain in the soil for years... and germinate after another fire wipes out the plants again! When this happens, dense "stands" of plant grow, covering the field with the tall, bright pink plants (though it can also be white). It can grow up to eight feet tall!

Fireweed, Wendy's favorite flower, is a perennial plant, meaning that it lives for more than two years, native to the temperate Northern Hemisphere. As a perennial in a temperate climate, it grows during the growing season and is dormant and loses its foliage during the winter ("seasonality" can mean warm and cold periods or wet and dry periods). This qualifies fireweed as a deciduous perennial. So, fireweed blooms during growing season (last frost to first frost) and that varies on your location. According to The Old Farmer's Almanac, Seattle's growing season is 232 days long. Therefore, for the immediate Seattle area, fireweed's growing season is March 24th to November 11th.

Fireweed is the floral emblem of the Yukon.

The link to this phograph on the web is here.

The link to this photograph on the web is here.

8/4/07

We're glad you asked.

Why is snow pink? What's the difference between dog hair and fur? When do salmon spawn? Do they clean resevoirs? When does fireweed bloom?

Testing, testing

Is this thing on? Check? Check?