An Investigation into the Physiological Impacts of Ocean Acidification on Recruits of the Temperate Coral, Oculina arbuscula

Author

Brianne Varnerin, Georgia Southern UniversityFollow

Term of Award

Spring 2018

Degree Name

Master of Science in Biology (M.S.)

Document Type and Release Option

Thesis (open access)

Copyright Statement / License for Reuse

This work is licensed under a Creative Commons Attribution 4.0 License.

Department

Department of Biology

Committee Chair

Daniel Gleason

Committee Member 1

J. Scott Harrison

Committee Member 2

John Carroll

Abstract

Ocean acidification is well-researched with respect to adult scleractinian corals, however information on whether adults and recruits of the same species respond similarly to this environmental stress is lacking. I investigated the responses to increased pCO₂ of recruits of the temperate coral, Oculina arbuscula, whose adults are known to withstand high levels of pCO₂ with no depression in calcification (up to 1000 ppm CO₂). I addressed the hypothesis that O. arbuscula recruit health is not affected by increased pCO₂ by exposing small colonies (5-12mm diameter) to 475, 711, and 1270 ppm CO₂ for 75 days. Calcification rates were monitored throughout the experiment, while mortality, respiration rates, photosynthetic rates, zooxanthella densities, and soluble protein were determined at the end. As predicted, higher pCO₂ did not impact survival, zooxanthella densities, or soluble protein. In contrast, both calcification rates and photosynthesis:respiration (P:R) ratios tended to be lower at higher pCO₂. These results suggest that there is a size-dependent response to pCO₂ within O. arbuscula, with recruits being unable to keep up with the increased energetic cost of calcification that occurs at higher pCO₂. With the mean pCO₂ increasing approximately 2.4% each year in the South Atlantic Bight (SAB), within the next 30 years O. arbuscula recruits are predicted to experience seasonal depressions in calcification rate driven by the overlying natural fluctuations in oceanic pCO₂, and within 50 years recruits are anticipated to exhibit year-round depressions in calcification rate.

Recommended Citation

Varnerin, Brianne, "An Investigation into the Physiological Impacts of Ocean Acidification on Recruits of the Temperate Coral, Oculina arbuscula" (2018). Electronic Theses and Dissertations. 1740.
https://digitalcommons.georgiasouthern.edu/etd/1740

Research Data and Supplementary Material

No