Roof Cleaning of Mid MO

What are the dark streaks on my roof? It's not mold. It's probably not soot. The black spots discoloring your asphalt roof are more than likely the pervasive and prevalent algae known as Gloeocapsa Magma. These roof-invaders require a moisture-rich environment, usually supplied by dew and shade. The first stains usually appear on the north-facing sides of a roof, which receives less light, and in areas with heavy tree coverage. Algae travels through the air, so if one neighbor receives a few spores, the whole neighborhood will soon be sporting the black streaks. The buildup of Gloeocaspa magma on residential properties has led to earlier roof replacements, lowered property resale values and insurance companies canceling policies.