Meeting Abstract

P1-109   -   Antioxidants may reduce endosymbiont expulsion and prevent bleaching in corals Guerra, AM*; Sanchez-Garcia, M; Varade, M; Roberson, LM; University of Montana, Missoula, MT; Marine Biological Laboratory, Woods Hole, MA; Marine Biological Laboratory, Woods Hole, MA; Marine Biological Laboratory, Woods Hole, MA amber.guerra@umontana.edu

Corals have a symbiotic relationship with photosynthetic Symbiodineacea, an intracellular micro-algal dinoflagellate group that reside within the gastrodermal tissue of the host coral. The nutrients produced by these endosymbionts provide sustenance to the coral, fulfilling energy needs for growth, reproduction, and nutrient efficiency. ‘Bleaching’ occurs when thermal stress causes a buildup of reactive oxygen species (ROS) in coral tissue, resulting in the expulsion of the endosymbionts and is related to rise in sea temperature. Previous studies on Porites asteroides suggest antioxidants such as L-ascorbic acid and catechin are ROS scavengers and help reduce ROS buildup in coral tissue, thereby reducing the number of expelled endosymbionts. We are testing whether these antioxidants reduce stress in the coral Astrangia poculata when used with a camphor bleaching treatment. A. poculata is a scleractinian coral native to the western Atlantic to the Gulf of Mexico, can function in both aposymbiotic and symbiotic states, and is highly tolerant of temperature changes, making it an ideal model system for this study. The treatments consist of the exposure of corals to antioxidants, camphor to mimic cold stress, and both camphor and antioxidants simultaneously. Photosynthetic efficiency (Fv/Fm), symbiont density, and calcification were measured throughout. While there was not a substantial change in calcification, we found that exposure to antioxidants during bleaching reduced endosymbiont expulsion and helped maintain normal levels of photosynthetic yield.