Publication Date
Fall 2025
Abstract
The Great Barrier Reef is home to a variety of hermaphroditic broadcast spawning coral species that only release gametes to reproduce once a year. The limited opportunity to collect these gametes to understand a scleractinian coral’s early ontogeny caps the knowledge on their development prior to early settlement on the reef substrate. Corals can produce green fluorescent proteins during their development, but the biological function for this fluorescence is still widely hypothesized. This study aims to track hermaphroditic broadcast spawning species fluorescence, Acropora millepora and Platygyra sp., during their development from egg to early settler. The expression of green fluorescent proteins is assessed to determine if the change in fluorescence is an indicator of a change in developmental stage. This was accomplished by collecting coral gametes during the mass spawning event in early November near Lizard Island, Australia, and rearing eggs until early settlement at the Lizard Island Research Station. Fluorescence was observed at every developmental stage, and the use of fluorescence made it possible to see differences between morphology at each stage. Fluorescence was measured as mean green intensity per individual. Quantitative analysis revealed statistically significant differences in mean green intensity from the oocyte to motile larval stage between species, and a significant sequential drop in mean green intensity between competent larvae and initial settlers within species. Since fluorescence was quantified here as a mean, fluorescence intensity did not necessarily drop as the coral settled but became much more concentrated as the protein differentiated near the developing mouth and tentacles, leading to a lower overall fluorescence signal per area. Change in fluorescence can be used as an indicator as the coral transitions from larvae to settler, and fluorescent proteins provide a more distinct function once the coral has settled and completed metamorphosis.
Disciplines
Life Sciences
Recommended Citation
Kroll, Mollie, "Presence and change of fluorescence in two broadcast spawning hermaphroditic coral species through development from egg to early settlement" (2025). Australia: Rainforest, Reef, and Cultural Ecology. 9.
https://digitalcollections.sit.edu/ase2/9