Effects of hypoxia on egg capsule conductance in Ambystoma (Class Amphibia, Order Caudata)

Aquatic amphibian eggs frequently encounter hypoxic conditions that have th e potential to limit oxygen uptake and thereby slow embryonic development a nd hatching. Oxygen limitation might be avoided if egg capsule surface area and oxygen conductance increased in response to hypoxia. We investigated t his possibility in two salamander species, Ambystoma annulatum and Ambystom a talpoideum. The effective surface area of egg capsules increased in respo nse to hypoxia, which increased the conductance for oxygen and enhanced oxy gen transport. The ability of amphibian eggs to adjust their conductance in response to oxygen availability may increase survival in hypoxic environme nts.