Octocoral Physiology: Calcium Carbonate Composition and the Effect of Thermal Stress on Enzyme Activity

• Main Author: Pearson, Hadley
• Format: Thesis
• Language: English
• Published: 2014
• Subjects: QL Zoology; QP Physiology; Ocean acidification
• Online Access: http://thesis.honors.olemiss.edu/100/; http://thesis.honors.olemiss.edu/100/1/Hadley%20Pearson%27s%20Thesis%20-%20Final%20Draft.pdf

Octocorals are a diverse group of organisms, and within the Caribbean they contribute substantially to coral-reef cover. In this thesis, two different studies performed on these marine organisms are detailed. In Section I, the percent calcium carbonate composition of several species was analyzed. Octocorals produce sclerites: calcium carbonate crystals that serve as the skeletal elements of the coral. Determining the percent calcium carbonate composition of eight Caribbean octocoral species can give comparative insight into the form and function in these animals. This study also offers clues about potential evolutionary tradeoffs between rigidity and flexibility, as well as establishes some basic physiological information about octocoral species in the Caribbean. Since calcification in organisms such as corals can be affected by the ocean acidification seen with climate change, this baseline is an important reference for future studies. Further, the increased intensity and frequency of violent storms due to global warming might prove to be especially damaging for more rigid species. Section II focuses on the effect of elevated temperature on one octocoral species over a period of ten days. The effect of temperature change was inferred from changes in activity of peroxidase and catalase, two enzymes that neutralize hydrogen peroxide produced in response to stress. The results show that the species did exhibit changes in enzyme activity in response to thermal stress. These enzyme activity changes will aid in understanding how this gorgonian coral species may respond to climate change.