The Colors of the Hot Springs

The colors of the hot springs in Yellowstone are something to behold.  This is a runoff area from Grand Prismatic Spring.  What you are looking at is all covered with water - not very deep.  On top of the hot water leaving the spring is something called a "microbial mat."  The mats produce colors ranging from green to red; the amount of color in the microbial mats depends on the ratio of chlorophyll to carotenoids and on the temperature of the runoff. In the summer, the mats tend to be orange and red, whereas in the winter the mats are usually dark green.  It is just one more amazing thing - you see it, but you can't quite believe your eyes.