UV-ABSORBING COMPOUNDS 



BRUCE E. CHALKER 



Australian Institute of Marine Science 

 P.M.B. No 3. 

 Townsville 4810 

 Queensland, Australia 



ABSTRACT: Marine algae and invertebrates living in exposed locations on coral 

 reefs are subjected to high levels of solar ultraviolet radiation. Many of these 

 organisms protect their tissues from the deleterious effects of ultraviolet 

 radiation (UV) by synthesizing specific UV-absorbing compounds. In most cases 

 the identities of these compounds are as yet unknown. An exception is the 

 mycosporine-like amino acids which have been identified in a variety of marine 

 algae and invertebrates, including reef-building corals. Reef corals typically 

 contain a suite of these compounds, each of which has an absorption maximum at a 

 wavelength between 310 and 360 nm. The UV absorption spectra for the combined 

 compounds overlap to form a broad-band filter in the UV-B region, and thereby 

 intercept physiologically damaging wavelengths of solar ultraviolet radiation. 

 The effectiveness of the mycosporine-like amino acids has led to their 

 consideration as model compounds from which a variety of synthetic analogues are 

 now being developed for use in personal suncare preparations and protective 

 coatings. 



Sequestering UV-absorbing compounds is one adaptive strategy which is available 

 to many, but not all, marine algae and invertebrates. Specific UV-absorbing 

 compounds have also been identified in the eggs of some fish. The extent to 

 which this UV photoadaptation might ameliorate the potential damage caused by 

 increasing solar ultraviolet radiation in the Antarctic is completely unknown. 

 It follows that researchers wishing to assess the biological impact of increased 

 solar ultraviolet radiation should screen their experimental organisms for the 

 presence of these compounds, and determine the types and quantities of compounds 

 when they are indicated. Ecologically appropriate time for photoadaptation prior 

 to exposing organisms to abnormally high levels of UV radiation should also be 

 provided. 



REFERENCES 



Dunlap, W.C, and B.E. Chalker, 1986. Identification and quantitation of near-UV 

 absorbing compounds (S-320) in a hermatypic scleratinian. Coral Reefs 5: 155- 

 159. 



Dunlap, W.C, B.E. Chalker and J.K. Oliver, 1986. Bathymetric adaptation of 

 reef-building corals at Davies Reef, Great Barrier Reef, Australia. III. UV-B 

 absorbing compounds. J. Exp. Mar. Biol. Ecol . 104: 239-248. 



Hirata, Y., D. Uemura. K. Ueda and S. Takano, 1979. Several compounds from 

 Palvthoa tuberculosa (Coelenterata) . Pure and Applied Chem. 51: 1875-1883. 



Jokiel, P.L., 1980. Solar ultraviolet radiation and coral reef epifauna. 

 Science 207: 1069-1071. 



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