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Aquatic Rainbow

Posted by
Steve Carey (Fairhope, United States) on 14 January 2020 in Plant & Nature and Portfolio.

What at first appears to be an oil slick on the surface of a swamp in coastal Alabama, is actually a natural phenomenon. The iridescent sheen on the water's surface is caused by the chemical reduction of iron in wetland soils by certain bacteria. These anaerobic bacteria reduce iron from one form to another, and the colorful sheen is a form of iron compund floating on the surface. This image was taken late afternoon in December, 2019 on the campus of the University of Mobile in the floodplain swamps adjacent to Chickasaw Creek (the creek borders part of the 900 acre campus).

OLYMPUS E-620 1/80 second F/5.6 ISO 200 42 mm