Foam - a Naturally Occurring Phenomenon

This article from the State of Michigan (DEQ) is about foam often found on lakeshores.

https://www.michigan.gov/documents/deq/deq-oea-nop-foam_378415_7.pdf

As well as an article from the Traverse Record-Eagle

http://record-eagle.cnhi.newsmemory.com/publink.php?shareid=2c4ec6def