title: UV-A induced delayed development in the larvae of coral Seriatopora caliendrum.
abstract: Coral reefs are vulnerable to ultraviolet radiation (UVR, 280-400nm). Not only do the fluxes of UVR fluctuate daily, they are also increasing due to global ocean and atmospheric changes. The deleterious effects of UVR on scleractinian corals have been intensively studied, but much less is known about the response of corals in the early pre-settlement phase. In this study, we tested how UVR exposure affects survival and development of Seriatopora caliendrum larvae and examined the photophysiological changes induced in the symbiotic dinoflagellate Symbiodinium. Results showed that the contents of chl c and carotenoids normalized to the number of algae cells in the larvae decreased significantly when larvae were exposed to UVR compared to those protected from UVR, while the cell density of Symbiodinium was higher in UVR-exposed larvae. The effective photochemical efficiency of the symbiotic algae increased when cultured under PAR plus UV-A (here taken as 320-395nm). We further present the novel finding that during the development experiment, presence of UV-A induced a decline in the rates of metamorphosis and settlement, which disappeared when the larvae were also exposed to UV-B (here defined as 295-320nm). However, UVR had no distinguishable effect on the numbers of larvae that either survived, metamorphosed or settled by the end of the culture period. Therefore, it is concluded from this study that UV-A radiation may extend the planktonic duration of coral larvae, but not have an overall inhibitory effect on developmental outcomes.
authors.affiliation: State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, Fujian, Republic of China.
authors.forename: Jie
authors.initials: J
authors.lastname: Zhou
authors.affiliation: National Museum of Marine Biology and Aquarium, Pingtung, Taiwan, ROC; Institute of Marine Biology, National Dong Hwa University, Pingtung, Taiwan, ROC.
authors.forename: Tung-Yung
authors.initials: TY
authors.lastname: Fan
authors.affiliation: State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, Fujian, Republic of China; School of Biological Sciences, Monash University, Clayton, Victoria 3800, Australia.
authors.forename: John
authors.initials: J
authors.lastname: Beardall
authors.affiliation: State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, Fujian, Republic of China. Electronic address: ksgao@xmu.edu.cn.
authors.forename: Kunshan
authors.initials: K
authors.lastname: Gao
mesh_terms: D000818:Animals; D037421:Anthozoa / Q000254:growth & development / Q000528:radiation effects*; D004141:Dinoflagellida / Q000254:growth & development / Q000378:metabolism / Q000528:radiation effects*; D007814:Larva / Q000528:radiation effects*; D010788:Photosynthesis; D010860:Pigments, Biological; D013559:Symbiosis; D014466:Ultraviolet Rays
chemical_list: D010860:Pigments, Biological
keywords: Coral larvae; Settlement; Symbiodinium; Ultraviolet radiation