making them good candidates for environments with low nitrogen rates. Nostoc, first discovered in the 19th century, is one of the most widespread phototrophic bacteria in the world. As a nitrogen fixer, these bacteria may provide plants with important nutrients and therefore can be used agriculturally. In 1988 a terrestrial species, Nostoc commune, was found to harbor a previously unidentified UV-A/B absorbing pigment. This protective pigment has enabled them to survive not only while under hydration-related stress, but in areas of extreme UV radiation as well.