The impact of competition, predation and disease on fluorescence patterns of RFP and GFP across the surface of scleractinian corals

Globally, scleractinian coral populations are declining, and to fully understand this decline it is important to study potential coral stressors in-situ. One particularly interesting means of studying stressor effects is fluorescence in corals. Till now fluorescence research has focused primarily on laboratory studies. These experiments cannot fully account for real world effects of stressors such as disease, predation or competition on corals fluorescent patterns in nature. The purpose of this study was to develop a means of in-situ observation to study how coral are using fluorescent proteins in nature. Five sample organisms were used for each of the three categories of stress, and one group of healthy corals were used as control, UV photographs of each were then taken on a weekly basis. Visual trends across the photographs were analyzed for gradients in both red and green fluorescence using Photoshop. From this we detected patterns on predated and competing corals as well as significant gradients in both diseased and healthy corals. Healthy coral results indicated issues in light dispersal across coral colonies necessitating a reworking of the methodology for clearer results. However the presence of discernable trend lines across all other categories supports that this methodology could still be effective for future monitoring efforts. RFP and GFP associated proteins are good candidates for indicating the health of threatened coral reefs due to their ease of use and associations with important coral functions making the methodology discussed here significant in allowing their use.

This student research was retrieved from Physis: Journal of Marine Science XIX (Spring 2016)19: 64-73 from CIEE Bonaire.