Millions of Years ago:
Cyano bacteria has
existed on earth for millions of years.
It is a simple micro organism
that grows in colonies.
Bacteria spores are carried by wind, birds,
squirrels, etc.
These colonies of algae need three things to grow:
Heat, moisture, and nutrients.
Typically, they are seen
on fences, and close to the ground bricks where nutrients can be found.
1890 - 1949
Asphalt was soaked onto a mat made from felts
containing cotton or wool fibers.
1950 - 1977
Cellulose fibers
derived from recycled paper or wood chips were used to make the asphalt shingle
mat.
1977 - today
An Inorganic fiberglass mat is coated with asphalt
that is then covered with a protective layer of U.V. resistant, colored ceramic
granules. Limestone is used as a void filler between individual mats and also
provides resistance to fire and weather.
Unfortunately, limestone
is a favorite food for "cyano bacteria gloeocapsa".
Prior to
1977, cyano bacteria would starve to death when it landed on your roof - now it
thrives on your roof.
As the algae grows, it holds moisture allowing
the growth to accelerate.
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