Chester Creek Grows Giant Pulsating Brain

Ok, so who can explain what causes that foam up/brain growth? The same foam formed below the beaver dam on the edge of my property today--and the drainage for the creek includes only about 4-5 rural houses, a cattle pasture, and a short segment of Hwy 13. 

I assume this foaming is a "natural" phenomenon since an urban stream and a rural one far away both exhibit it, but who can best explain it? Is it spawn of the infamous Duluth Monster?

It's santorum.

The warmer temps cause organic materials to break down faster which release certain acids and compounds from soils into the water that affect its surface tension. In a turbulent flow, you get this sudsing effect. A detergent spill could also do it, but then the bubbles would be bleach white, perfumey, and would last longer past the turbulent flow. Also, giant pulsating brains are telepathic and made me write this with mind control.

For all you wanted to know about foam check out the Lake Superior Streams website.