A HAB is a Harmful Algal Bloom, which occurs when colonies of algae grow out of control, occasionally producing toxins that can kill fish, mammals, and birds and cause human illness. HABs are a growing problem in waterways everywhere, including the Adirondack Park. They are associated with cyanobacteria, some species of which can produce powerful cyanotoxins. These improvised bowls are meant to mimic the look of some of the cyanobacteria that we see in the microscope when we look at images from water samples associated with HABs. 

More details available here on Ravelry.

Creator: Michale Glennon