Dotspotting Expressionist Science: What the Mysterious Color-Markings on Storm Drains Have to Do with Rachel Carson’s Legacy and the War on a Deadly Virus

Strange signals from the lacuna between street art and microbiology.

I noticed them first in my neighborhood — dots of paint hovering over the grate of the storm drain in a blue-green spectrum punctuated by white. I noticed them probably because I had been writing about the wondrous science of the color blue and my brain had formed, as brains tend to, a search image for its present preoccupation.

At first I took them for mindless spray-can tests by a street artist getting ready to graffiti a...