Photos taken by Melanie Mormile
Other indicators of microbial activity include mats, flocculent material, and oily sheen residues. The mats are groups of microbes, usually photosynthetic.
The green color in the left photo indicates that photosynthesis is going on. The middle photo shows white and orange flocculent material. The orange color
is probably iron and the microorganisms are making a rust-like material. The photo on the right shows an oily sheen but it is not oil. Manganese oxidizing
bacteria make this. If you find an oil sheen around a stream, poke it with a stick. If it cracks and breaks, you have found manganese oxide that bacteria
have made!
|