Meeting Abstract
Global climate change, caused primarily by a substantial increase in the burning of fossil fuels since the Industrial Revolution, has strong impacts on marine ecosystems. Ocean acidification and warming sea surface temperatures are the results of the oceans absorbing the excess carbon dioxide and heat from the atmosphere. These changes in water conditions may have a variety of detrimental impacts on marine organisms. Cephalopods may be particularly sensitive to changes in environmental pH due to their use of hemocyanin as an oxygen transport pigment, which has strong Bohr and Root effects. Thus, the affinity and carrying capacity of hemocyanin for O2 is decreased in a low pH environment. In addition, sensitivity to pH is increased in warmer temperatures. We constructed energy budgets for Octopus rubescens exposed to high pCO2 and high temperature treatments, both separately and combined. Energy budgets were calculated based on metabolic rates, consumption, and growth. We also measured the critical oxygen pressures of each octopus after five weeks of treatment because of the possibility of reduced oxygen transport in these conditions. Our results suggest that energy budgeting is altered in response to expected climate change conditions, with significantly more energy allotted to growth and metabolism than when in control or single treatment conditions. Additionally, the critical oxygen pressure is significantly increased when exposed to the combined higher pCO2 and temperature, suggesting that O. rubescens may have a reduced habitat range due to decreased hypoxia tolerance.
