A quantitative survey of mycosporine-like amino acids (MAAS) in intertidal egg masses from temperate rocky shores

Mycosporine-like amino acids (MAAs) have been reported as functional chemical sunscreens in a variety of marine organisms, but their role in development of marine embryos and larvae remains largely unexplored. In this study, we quantified MAAs from intertidal egg masses of 46 species of mollusks, two species of polychaetes, and one species of fish from southeastern Australia. We aimed to elucidate potential patterns of occurrence and variation based on egg mass maturity, adult diet, spawning habitat, phylogeny, and viability. Our analyses revealed that maturity and spawning habitat did not affect MAA composition within egg masses. In contrast, adult diet, phylogeny, and viability affected MAA composition. Herbivores had higher levels of certain MAAs than carnivores; similarly, viable egg masses had higher levels of some MAAs than inviable ones. MAA composition varied according to the taxonomic group, with nudibranchs and anaspids showing different MAA composition compared to that of neogastropods, sacoglossans, and polychaetes. Basommatophoran egg masses had more porphyra-334 than the other taxa, and anaspids had more mycosporine-2-glycine than the other groups. MAAs occurred in relatively high concentrations in intertidal molluskan egg masses when compared to adult mollusks and other common intertidal organisms. Despite the complexity of factors affecting MAA composition, the prevalence of MAAs in some species is consistent with protection afforded to offspring against negative effects of UV radiation.