HACHTMAN., R.; RANCK, F.; ROSE, J.; RYAN, W.L.*; Kutztown University of Pennsylvania: Oxygen Measurement as an Indicator of Optimum Light Conditions for the Sea Anemone Aiptasia: Normal vs. Bleached Individuals

The sea anemone, Aiptasia, is a nuisance for home aquarists, in part because of its ability to reproduce from fragments and in part due to the presence of algal symbionts. This study took advantage of Aiptasia‘s ruggedness to model the bleaching of hermatypic corals. The response of both normal and bleached anemones to different light regimes was examined by measuring their net production (or consumption) of oxygen. The light regimes used approximated the light wavelengths available at depths of 0 m, 30 m, and the bottom of the photic zone, plus a control. In the unbleached or normal anemones, net oxygen production was measured under all light conditions evaluated, with significant decreases (ANOVA, P < 0.05) based on the wavelengths of light available to their symbiotic dinoflagellates. None of the bleached anemone treatments resulted in a significant change in oxygen levels during the one-hour equilibration period. In comparing the results of the normal and bleached anemone treatments, three of the four light regimes were significantly different (Student’s t-test, α = 0.05), with the treatment representing the bottom of the photic zone showing no significant difference. In interpreting these results, normal anemones appear to have a competitive advantage over bleached anemones at all but the deepest depths. Future studies could evaluate the feeding strategies of normal and bleached anemones under these conditions to see if there are any differences in this aspect of their ecology. The sample sizes for this preliminary study were small, with only ten animals per treatment; however, this model appears useful in examining the role of symbionts in the success of Aiptasia, and further study seems warranted.