As coral reef experts from around the world hone their efforts to understand and address the grim news coming from Australia, where continuous bleaching has damaged a significant part of the world’s largest and most famous coral reefs, environmental activists in Hawaii are focusing on what can be done in waters closer to home.

A good starting point, as extensively discussed at the recently concluded International Coral Reef Symposium at the Hawai‘i Convention Center, could be the very thing that conscientious ocean-users slather on their skin to protect against harmful ultraviolet radiation.

In a study published in the science journal Archives of Environmental Contamination and Toxicology in February, a research team headed by Craig Downs, executive director of the Haerecticus Environmental Laboratory in Virginia, reported on a link between oxybenzone, a key ingredient in sunscreen lotions and personal-care products that protect against UV rays, and so-called coral bleaching.

The team found that oxybenzone, the adverse effects of which are intensified by light, deformed the larval form of coral called planula.

In effect, high concentrations of oxybenzone caused planula to become sterile and eventually encase itself in its own skeleton, creating what scientists have termed “zombie” coral.

While the chemical does not directly kill coral reefs, it can prevent living coral from properly recovering and regenerating.

The study looked at oxybenzone contamination in waters around Hawaii and the U.S. Virgin Islands. According to the study, oxybenzone toxicity occurs in concentrations as low as .062 micrograms per liter. The study found that contamination in the area of the U.S. Virgin Islands was as high as 1,400 micrograms per liter, while in Hawaiian waters the concentration ranged from .08 to 19.2 micrograms per liter.

“Oxybenzone poses a hazard to coral reef conservation and threatens the resiliency of coral reefs to climate change,” the study said.

A measure that would have called for a study of the effects of sunscreen on coral reefs failed to advance through the state Legislature this year. The bill was introduced by Reps. Lynn DeCoite, Ty Cullen, Sharon Har, Kaniela Ing, Jarrett Keohokalole, Nicole Lowen, Dee Morikawa, Feki Pouha, Calvin Say, Ryan Yamane and Cindy Evans.

More aggressive measures calling for an outright ban on oxybenzone are expected to be introduced next session.

The study offered both disturbing news and a glimmer of hope (that immediate address can prevent significant further harm) at a time when coral reefs are experiencing a historic threat due to climate change.

Consecutive years of warmer-than-normal temperatures have already led to alarming levels of coral bleaching.

Warm waters cause corals to expel an important algae living in their tissues, causing the coral to turn white. While corals can survive a bleaching event, they experience greater stress and are more likely to die, according to the National Oceanic and Atmospheric Administration’s National Ocean Service.

In 2005, the U.S. lost half of its coral reefs in the Caribbean in one year due to a massive bleaching event. Satellite data from the previous 20 years confirmed that thermal stress from the 2005 event was greater than the previous 20 years combined, NOS reported.

NOAA scientists have been tracking an unprecedented global coral bleaching event that is stretching into its third year.

According to the administration, every major reef region has experienced severe bleaching, including 93 percent of the reefs that constitute Australia’s Great Barrier Reef.