I took photos of these turtles the other day, actually just two of them though there were lots more around. These drifted in front of my camera lens.
I was quite shocked to see how much moss and algae had grown on this one's back. I didn't notice how much until the photo was enlarged on the computer screen later on that day. Told quite a story, at the very least he has been around a very long time, a veritable great-grandpa of a turtle and a pretty good size.