Photo credit: Jim LanierThere is an old saying that “you can’t judge a book by its cover.” That may be true for the literary world but when it comes to lakes, the color of your water — or maybe the lack thereof — tells many a tale. There are many factors that have an effect on the color of your lake water including geology, organic matter and nutrients. In general terms, the less “stuff” there is in your water, the less color you will see in it. This is why mountains lakes have that crystal clear look — in most cases, the water is absent of “stuff.” I could go into more detail on this topic, but we’ll save that for another time.
Here’s what got my mind on lake color: I was fortunate enough to spend some time in Washington State recently and had the chance to visit some of the glacial alpine lakes near Mount Rainer. On close inspection the water of the lake was clearer than clear. But when viewing the lake from a distance, the lake water took on brilliant aquamarine blue, like the waters of the Caribbean but even more intense. So what’s the story? This phenomenon is known as the Tyndall effect, named after the 19th century physicist John Tyndall. The minute glacial silica particles suspended in the water of a glacial lake refract light; blue light is much stronger than red when fine particles are suspended in the water, so the result is a blue color.
You can try your own experiment on the Tyndall effect. Add powdered milk to water in a clear glass container, then shine a flashlight through the water: it will appear blue! Since we do not have glacial lakes here in the South, this type of lake color is not the norm — except maybe at Disney World . . . but that’s another story.
Until next time.
Jim
