What is on my turtles shell?

I can't see your pictures (it's my computer, not your links), but I'm going to venture a guess and say it's just algae growth, and it's perfectly harmless. If you take a towel and can wipe it off fairly easily, then it's algae and you shouldn't worry about it. If the temps are right in your tank (about 80 degrees F water, 90-95 degrees F basking area), then you're fine. =)