LAUSR

Increased ultraviolet radiation (UVR) is a major environmental stressor for marine organisms. The response of planktotrophic larvae of holo- and meroplanktonic crustaceans fed dietary algae grown under different light regimes and contents of UV-absorbing compounds (UACs), was experimentally evaluated. Paracalanus parvus copepodites and Cyrtograpsus angulatus zoeae were fed diatoms grown under two radiation treatments: PAR (400-700 nm, produced by 40 W cool-white fluorescent bulbs) and PAR + UVR (280-700 nm; adding Q-Pannel UV-A-340 lamps to PAR fluorescent bulbs). An absorption peak at 337 nm (UVR range) was observed only for larvae fed UVR-irradiated diatoms. After 144 h of ad libitum feeding, larvae were exposed to UVR for 24 h. Mortality rates were ~80% in individuals fed PAR-reared microalgae, and ~10% for those fed UV-irradiated microalgae. Results point to the importance of UACs conferring some tolerance to planktotrophic larvae under increased environmental UVR stress. Yet, acquired tolerance is differential among larvae, with implications for zooplankton ecology.