Meeting Abstract
Like some corals, many sea anemones have symbiotic relationships with photosynthetic dinoflagellates of the family Symbiodiniaceae, sometimes referred to as zooxanthellae. In the process known as bleaching, this relationship is disrupted and the dinoflagellates are expelled from the cnidarian tissue, causing it to turn white. We were curious about the individual and combined effects of two consequences of climate change, rising sea surface temperature and ocean acidification, on bleaching. We exposed individuals of the symbiotic anemone Exaiptasia pallida to one of three treatments: warmed water, water acidified by the addition of carbon dioxide, or water that was warmed and acidified, and compared their responses with controls. Data from chlorophyll fluorometry and images from fluorescence microscopy permitted us to monitor symbiont loss. Anemones in the heated and combined treatments showed different rates of bleaching whereas those in the acidified treatment showed no loss of symbionts. These results indicate that there is a complex interaction between the effects of elevated temperature and enhanced carbon dioxide on this symbiotic relationship. Thus, it is important to take both factors into account when evaluating the potential impact of climate change on bleaching.
