Corals and their allies are subject to many anthropogenic and natural stressors that have contributed to their worldwide decline. Coral bleaching is a stress response that causes corals to expel the symbiotic algae they associate with, particularly when the hosts are under stress. The sea anemone, Aiptasia pallida has been established as a model organism for cnidarian bleaching, but a baseline for minimal treatment that induces the bleaching response has not been established. Anemones in six 24-well plates were treated with 40 μM menthol with two plates being fully treated, two plates untreated and two with mixed (staggered arrangement). This concentration was effective for inducing aposymbiosis while producing the least visible damage to the host. Fluorescent photography was used to image anemones once a day for five days and images were analyzed using ImageJ and MATLAB to establish the degree of bleaching according to the specific pixel value for the host and symbionts. Results showed that anemones in the fully treated plate became aposymbiotic twice as fast as those in the mixed plate despite being exposed to the same conditions. However untreated anemones in the mixed plate also bleached suggesting that menthol may have evaporated and contaminated adjacent untreated anemones. Nonetheless, the software was able to effectively quantify bleaching in the anemones. This project outlines a protocol that for experiments involving fluorescence photography of Aiptasia pallida to test sensitivity to compounds that cause bleaching.
