Coming to Life
The intense colors of Yellowstone’s hot springs indicate the abundant life of thermophile bacteria at high temperatures along with algae and protozoa at more moderate temperatures. These photo-synthetic active microorganisms produce brightly colored mats when living in large communities. Growing together in layers of organic slime, microbes can intertwine forming long, hairlike filaments called streamers. The pigment of the photosynthesis is the green colored chlorophyll. When masked with carotenoids it produces yellow, orange and red shades in the mats. The color intensity shows a distinct summer maximum as the purpose of the carotenoid is to protect the cells from the UV-radiation part of the sunlight. During winter the mats show a more greenish appearance. The colors of the mats additionally depend on the species living in it. Hence the rings of colors indicates the temperature zoning of the hot pools. Microorganisms grow in abundance with temperatures between 113°F and 176°F (45 and 80°C). The water in the centre boils and hence only shows the reflected sky’s blue.
August 2008
Canon 20D, Canon EF-L 24-105mm, f/11, 1/30 sec, ISO 100 ASA, tripod