A compound found in sunscreen, is delaying the development of some jellyfish larvae, finds a new study from the University of Georgia. Drs Bill Fitt and Dietrich Hofmann tested the ability of jellyfish larvae to swim and metamorphosis, and found slow swimming larvae when oxybenzone concentrations in the water were highest.
Oxybenzone is known to be harmful to coral reefs, especially the development of tiny planula larvae, and was found to have a similar effect on the development of jellyfish larvae. The team observed the development of upside-down jellyfish (Cassiopea sp.) water with different oxybenzone concentrations and found larvae swam a third slower when the concentrations were highest 228µg L (micrograms per liter).
Using sunscreen while snorkeling, scuba diving, or swimming at the beach is the quickest way oxybenzone and other harmful chemicals enter the ocean. Studies have found oxybenzone concentration in ocean water tested at popular tourism beaches in Hawaii and the US Virgin Islands can be up to six times higher than the top concentration tested in this study.
Oxybenzone has been found to damage and deform planulae larvae, which could explain the slow swimming larvae observed in this study. Research reported the jellyfish larvae were swimming in irregular patterns, some spinning in circles in the same spot, and many of them died.
For larvae that made it past this initial phase, they still face a tough battle. The swimming impairment would make it harder for them to find a suitable rubble substrate for them settle and metamorphose into an adult jellyfish.
The study looked at two upside-down jellyfish species the Cassiopea xamachana, and Cassiopea frondosa and found larvae from C. frondosa were more sensitive. Although the study focused on these Atlantic jellyfish, it is possible the larvae of the Indo Pacific Cassiopea andromeda would suffer similar detrimental effects.
Next time you head to the beach stick with a reef safe sunscreen, and if you can avoid using chemical products especially on your next beach vacation. These include vegan or natural sunscreens, check the ingredient list, if there is something you can’t read, switch to a reef save natural list.