I have been noticing a little foam on the shoreline of Lake Metigoshe recently. It is not rare during the summer, but it more generally is associated with the dying of algae and aquatic plants during the fall. When they die and decompose, some of the organic substances act as surfactants.
Surfactants are substances that reduce the surface tension of water. Reducing the surface tension makes it easier for air to mix in with the water and form bubbles. And of course, foam is lots of little bubbles.
I suspect that many of you learned about surface tension as a kid by carefully filling up a glass with water (or other liquid) until the surface was actually above the rim of the glass! What entertainment! It was all about surface tension, even though we may not have realized it.
But back to lake foam. When the surface of a lake is agitated, by the wind, for example, surfactants in the water make it easier for air to get under the surface film of water and produce bubbles. If the water stays agitated for a long enough time, foam may form. We have had some windy days, and as you might expect, the foam was accumulating along the windward shoreline.
Back in the 1950’s or 1960’s seeing foam on a lake or stream may have been an indication of water pollution. Soaps and detergents were not biodegradable back then and would occasionally form large mounds of foam that smelled like, well, laundry detergent or soap (complete with artificial fragrances). Thank goodness those days are past. If you closely observe natural lake foam, it will often have a brownish tinge to it, and have a slight earthy or fishy smell. This foam is natural, poses no health concerns, and generally degrades in a few hours.
You might want to keep an eye out for falling stars in the next few weeks. The Delta Aquarids Meteor Shower started on July 12 and will go until August 23. The peak viewing period will be the night of July 28th with perhaps up to 20 meteors per hour. The moon should not interfere much, so if the sky is clear viewing could be quite good.
~Chuck Lura
