Gloeocapsa magma

Gloeocapsa magma is blue-green algae, which is cyanobacteria, it is a type of algae. Algae are polyphyletic, and major algal groups are not all closely related to each other. Algae is NOT a taxonomic category, it is just a common name for all things photosynthetic that are NOT plants. Cyanobacteria are an ancient line of photosynthesizing bacteria, responsible for Oxygen gas in the atmosphere. It can be said that Cyanobacteria are responsible for all advanced forms (eukaryotic cells) of life on earth. It has gained notoriety in the Southeastern U.S. which is quickly spreading throughout the Midwest. The reason is this particular type of blue-green algae is responsible for creating the unattractive black roof stains and/or streaks commonly noticed by many. The blue-green algae, unicellular, accumulate over time; this accumulation begins to show the problematic black stains as the cyanobacteria develop their dark and hard UV-protective outer coating.

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The primary reasoning behind the rapid spread and noticeabilty of this algae is:

1. Rising humidity and temperatures combined with more and more bacteria spores promotes their spread with these favorable conditions.

2. Fiberglass shingles (the most commonly seen amongst today's residential homes) have been being made with limestone as a filler (in the asphalt). These shingles hold moisture and organic "bacteria food" material longer (especially on the North-side in the Midwest) than the paper/asphalt/ceramic shingles of 20+ years ago. Additionally, these particular algae enjoy the limestone as a food source.

Once the blue-green algae have become noticeable, the stains will continue to worsen year to year. There is debate over the actual harmfulness of this particular blue-green algae to roofs, as there is little supportive scientific research. However, most "experts" within the subject area conclude the blue-green algae to be harmful, if left untreated, as the growth holds moisture within shingles causing premature aging, rotting, and/or granule loss.

To rid roofs of these stains, shingle manufacturers recommend a mixture of TSP (Trisodium phoshate), household bleach, and water. Roof cleaning will not affect shingle warranties and is recommended by manufacturers to remove bacteria and similar roof growths*. However, safety is of main concern when cleaning a roof. Getting solution to hard to reach areas and thoroughly cleaning a roof will often require one to climb and navigate the roof. If you have any doubt about your roof climbing abilities or are not familiar with roof navigation, leave the job to professionals to prevent injury and property damage. -Article by Zac Pfaff but inaccuracies have been edited.

References/Links

http://www.owenscorning.com/around/roofing/troubleshooting.asp*

http://www.midwestprowash.com/roof_algae_report.html