Turtle shells are white?

[baker_eliz]

We have a large farm pond in the SF-North Bay area, and it does get runoff from the hills surrounding us, including runoff on one side from an "organic" olive tree grove.

Yesterday and today we had two turtles show up on our turtle island, the first turtles we have seen this year, and it seems a bit early for them. I am concerned because their shells look bleached or ashy, not the green I am accustomed to seeing.

Anyone know what the cause of this could be? Is this their normal color when hibernating? Do I need to be concerned?

Thanks, Elizabeth

 

[Stephen Noble]

I am not familiar with any turtle that normally has a green shell suddenly showing up with a white shell except sick turtles. There is another possibility. It could be the white/ash color is dried algae that takes an ashen color in the sunlight. It is normal when they shed scutes for a few of the scutes to turn a lighter color but not the entire shell. What type of turtles are they? Are you certain they are aquatic or semi-aquatic turtles? Could they be terrestrial turtles displaced by the rains? Could you please post a picture? I'm willing to bet it is dried algae. Just further thinking this out, do you have extremely hard water?