The effects of hypoxia on active ionic transport processes in the gill epithelium of hyperregulating crab, Carcinus maneas

In response to a 4 day exposure of Carcinus to 2.0 mg O2/L, hemolymph Na+ and Cl− concentration decreased, i.e. hyperosmoregulation was weakened. Variations of the oxygen concentration level and exposure time to hypoxia lead to an increase of the surface of mitochondria per epithelium area and might in part compensate for the decrease in oxygen availability under hypoxic conditions.