Discipline: Ecology Environmental and Earth Sciences
Subcategory: Plant Research
Room: Exhibit Hall A
Keanu Rochette-Yu Tsuen - Kapi'olani Community College
Scaevola taccada or naupaka kahakai is a native Hawaiian plant that grows commonly in coastal areas. Indigenous knowledge suggests that the fruits of this plant contain UV absorbing compounds. As such, the fruits of this native plant could potentially help reduce the use of commercial sunscreens on Hawaiian reefs. Prolonged exposure to commercial sunscreen chemicals (oxybenzone) affects coral growth and recruitment. Previous experiments have demonstrated that fruit extracts from S. taccada do contain compounds capable of absorbing UV radiation with a calculated SPF as high as 20. In this study, we investigated the UV stability of the juice over time in fresh, heated and frozen solutions and the toxicity of these treatments of S. taccada extract on coral colonies (Porites compressa) was measured. Specifically, various S. taccada treatments of the extract (FSW, fresh, heated and a negative control of Montipora capitata eggs with montiporic toxin) were incorporated into a 2% agar solution and filled into small plastic caps. The caps with several treatments were strapped onto 10 cm coral fragments to allow the gels to be in direct contact with the coral tissues and placed into flowing seawater. After four days of treatment, the effects of these treatments were analyzed macroscopically and microscopically with a colorimetric assessment and the photosynthetic yield of the symbionts. The UV stability of the various treatments was unchanging over time and were not different (p > 0.05). When these treatments were exposed to the corals, S. taccada extract had a 29.67% color change and 0.429 y in photosynthetic yield on average. Concentrated S. taccada extract had a 39.34% color change and an 0.068 in photosynthetic yield on average. The concentration of the juice made a difference to the physiology of the coral, but it is not known whether it was the active UV compound or some other aspect of the extract that was causing these changes. Further investigation will be performed to study the effects of diluted S. taccada extracts in seawater. References: Hagedorn, M. A. Farrell, V. Carter, N. Zuchowicz, E. Johnston, J. Padilla-Gami?o, S. Gunasekera, and V. Paul. 2015. Effects of toxic compounds in Montipora capitata on exogenous and endogenous symbionts performance and fertilization success. PLoS One, 10(2) : e0118364. Downs, C. A., E. Kramarsky-Winter, R. Segal, J. Fauth, S. Knutson, O. Bronstein, F.R. Ciner, R. Jeger, Y. Lichtenfeld, C.M. Woodley, P. Pennington, K. Cadenas, A. Kushmaro, and Y. Loya. 2016. Toxicopathological effects of the sunscreen UV filter, oxybenzone (benzophenone-3), on coral planulae and cultured primary cells and its environmental contamination in Hawaii and the US Virgin Islands. Arch. of Environ. Contam. Toxicol, 70(2) :265-288.
Funder Acknowledgement(s): I thank the REU: Environmental Biology for Pacific Islanders for funding my project through their NSF grant, specifically Dr. Michael Hadfield and Dr. Matthew Medeiros.
Faculty Advisor: Mary Hagedorn, firstname.lastname@example.org