How a Turtle's Shell Helps It Survive Prolonged Anoxic Acidosis.

Anoxic turtles accumulate high levels of lactate in blood. To avoid fatal acidosis, turtles exploit buffer reserves in their large mineralized shell. The shell acts by releasing calcium and magnesium carbonates and by storing and buffering lactic acid. Together with profound metabolic depression, shell buffering permits survival without oxygen for several months at 3 degrees C.