Meeting Abstract
Cephalopods are active, mobile predators that are physiological convergent with vertebrates, despite using molluscan physiological components. To achieve oxygen loading/unloading dynamics similar to vertebrate hemoglobins, cephalopod hemocyanins exhibit a pronounced Bohr effect. This could potentially lead to respiratory impairment under acidified environmental conditions, such as those predicted to occur over the coming century. I measured routine respiratory rate of ruby octopuses (Octopus rubescens) that I acutely and chronically (5 weeks) exposed to elevated CO2 and measured critical oxygen pressure and ventilatory efficiency of octopuses chronically exposed to elevated CO2. I found that, while neither acute nor chronic exposure to elevated CO2 led to detectable changes in routine respiratory rate, critical oxygen pressure increased significantly when octopuses were chronically exposed to high CO2, and ventilatory efficiency was moderately lower. These data suggest that ocean acidification may make octopuses more sensitive to hypoxic conditions. This is particularly concerning as shallow water low oxygen events are becoming increasingly common in coastal habitats.
