It is fairly common around Sitka to see places where everything in the water is coated in an orange colored film. I used to think this was due to rusting pipes or something, but I could not figure out how or why there came to be pipes in places that were not close to town. Later I learned that this coloring is due to bacteria that can fix iron. So in a sense it is rust, but it comes from naturally occuring iron.
Location: Westwood Trail, Sitka, Alaska