Water flea, Daphnia magna (IMAGE) University of Alberta Caption Water flea, Daphnia magna, rougly 5mm across. Study results show that exposure to UV-filters over a 48-hour period prevented the fleas from navigating through their environment. Exposure over a 14-day period--similar to what might occur near popular beach areas--proved lethal for the tiny crustaceans. Credit Photo credit: Aaron Boyd Usage Restrictions For use with credit. License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.