Meeting Abstract
In this project, we investigated how the presence or absence of algal symbionts affects gonadal morphology of cnidarians. Specifically, we studied Aiptasia pallida, a subtropical species of anemone that can be found from North Carolina to the Florida Keys, on the eastern coast of Baja California, and around the Hawaiian Islands. This species typically maintains its caloric requirements through food intake combined with the photosynthetic products produced by mutualistic dinoflagellate algae of the genus Symbiodinium, although hosts can survive without their symbionts. Our previous research suggested that aposymbiotic anemones, which were reared in the dark and thus lacked algal symbionts, failed to develop gonads. However, we were not able to confirm whether the inability to develop gonads was due to the lack of symbiotic algae or to the lack of light. The purpose of this study was to determine the extent to which gonad development is dependent on the presence of symbiotic dinoflagellate algae. Gonadal development and spawning were induced in both aposymbiotic and symbiotic anemones by two consecutive 28-day cycles, each consisting of a 12h:12h light:dark photoperiod for 23 consecutive days and a 16h:8h light:dark photoperiod with simulated moonlight during scotophase for five consecutive days. Each week during the study, nine or ten anemones were anesthetized, fixed in seawater-buffered formalin, embedded in paraffin wax, and sectioned at 7 µm. Serial sections were then alternately stained using either a modified Masson trichrome stain or a standard hematoxylin and eosin stain. Morphological differences in size and number of oocytes or sperm follicles in the gonads and their implications in light of climate change will be discussed.
