Coral friendly sun block

[*Merlin*]

I read a magazine article about sun block that kills coral. The article suggested using sun block that contained zinc and a couple other active ingredients but it did not mention any products by name. Can anyone assist me with a coral friendly sun block?

[DevilDiver]

Swimmers' Sunscreen Killing Off Coral

Ker Than
for National Geographic News
January 29, 2008 The sunscreen that you dutifully slather on before a swim on the beach may be protecting your body—but a new study finds that the chemicals are also killing coral reefs worldwide.

Four commonly found sunscreen ingredients can awaken dormant viruses in the symbiotic algae called zooxanthellae that live inside reef-building coral species.

The chemicals cause the viruses to replicate until their algae hosts explode, spilling viruses into the surrounding seawater, where they can infect neighboring coral communities.

Zooxanthellae provide coral with food energy through photosynthesis and contribute to the organisms' vibrant color. Without them, the coral "bleaches"—turns white—and dies.

"The algae that live in the coral tissue and feed these animals explode or are just released by the tissue, thus leaving naked the skeleton of the coral," said study leader Roberto Danovaro of the Polytechnic University of Marche in Italy.

The researchers estimate that 4,000 to 6,000 metric tons of sunscreen wash off swimmers annually in oceans worldwide, and that up to 10 percent of coral reefs are threatened by sunscreen-induced bleaching.

The study appeared online in the journal Environmental Health Perspectives.

Activated Viruses

Danovaro and his team studied the effects of sunscreen exposure on coral samples from reefs in the Pacific, Atlantic, and Indian Oceans.

Even low levels of sunscreen, at or below the typical amount used by swimmers, could activate the algae viruses and completely bleach coral in just four days, the results showed.

Seawater surrounding coral exposed to sunscreen contained up to 15 times more viruses than unexposed samples.

Several brands of popular sunscreens were tested and all had four ingredients in common: paraben, cinnamate, benzophenone, and a camphor derivative.

Dangerous Dose

Robert van Woesik, a coral expert at the Florida Institute of Technology, was not involved in the research.

He questions whether conditions in the study accurately reflect those found in nature.

For example, the coral samples were exposed to sunscreen while in plastic bags to avoid contaminating the reefs. But van Woesik worries this prevented dilution of the chemicals through natural water circulation.

"Under normal situations on a coral reef, corals would not be subjected to these high concentrations because of rapid dilution," van Woesik said.

But according to study author Danovaro, the effect is not dose dependent—so coral's exposure to a very small dose of sunscreen is just as dangerous as a high exposure.

"It is more like on-off," he said. "Once the viral epidemic is started, it is not a problem of toxicity."

Alarming Trend

Rebecca Vega Thurber, a marine virus and coral researcher at San Diego State University in California, said the new results are further evidence of an alarming trend.

"Other [human-induced] factors such as coastal pollution, overfishing, and sedimentation all contribute to coral reef habitat degradation, and this work continues in that vein," said Vega Thurber, who was also not involved in the research.

(Related news: "Coral Reefs Vanishing Faster Than Rain Forests" [August 7, 2007].)

"But before we ban sunscreens, we must first determine if local ambient concentrations of sunscreens are positively correlated with coral bleaching events."

Danovaro says banning sunscreen won't be necessary, and points out two simple things swimmers can do to reduce their impact on coral: Use sunscreens with physical filters, which reflect instead of absorb ultraviolet radiation; and use eco-friendly chemical sunscreens.

(Read about other ways you can protect the oceans.)

Australian researchers are also working to develop a sunscreen based on a natural ultraviolet-blocking compound found in coral.




Science News –
January 23, 2008
Sunscreens go viral on coral

Ingredients in commonly used sun-protection products bleach reefs by stimulating latent viruses in algae.

The biological integrity of about 60% of the world's coral reefs is under assault, and the percentage of threatened reefs is expected to continue rising. Coral bleaching, which indicates the death of colored symbiotic algae that provide nutrients to coral, is a visible sign of this damage.

New suspects in the bleaching process include four commonly used sunscreen ingredients that routinely wash off into water, according to a team of Italian researchers who published their study online January 3 in Environmental Health Perspectives (2008, DOI 10.1289/ehp.10966). The ingredients killed the algae within just 4 days at very low levels, at or below what would be observed with typical usage by swimmers worldwide. The team says this is the first evidence linking sunscreens to coral bleaching.


The problematic ingredients included a paraben preservative and three types of UV filters—a cinnamate, a benzophenone, and a camphor derivative. The researchers conclude that these compounds likely kill algae by stimulating latent viruses that have been found in almost all classes of coral-inhabiting algae. The number of viruses in seawater surrounding coral samples exposed to the ingredients increased as much as 15-fold, and viruslike particles were found in and around the algae. All sunscreen brands, sun-protection factors, and concentrations tested bleached the coral.


The researchers used field and laboratory analyses to evaluate more than half a dozen coral species from sites in the Red Sea, the Caribbean Sea, the Andaman Sea in the Indian Ocean, and the Celebes Sea in Indonesia. They calculate that approximately 10% of the world's coral reefs are potentially threatened by about 4000–6000 metric tons of sunscreen that annually wash off swimmers in these and other reef waters. The rapid expansion of tourism in reef areas suggests to the researchers that destruction is likely to worsen unless sunscreen formulations that are safer for the coral are developed. —ROBERT WEINHOLD

[mixahl]

wow, i didnt know sunscreen was this bad!

[Murloc]

the coral was in plastic bags and exposed to the sunscreen.....is it just possible that the coral suffered harm because it was blocked from the movement of water?...I thought it was necessary for there to be a constant flow of water movement over coral for it to survive...or am I wrong?

[ratown]

Water flow is very necessary. I find it hard to believe that these scientists didn't put variables like water flow and volume into this experiment though. They could just be looking for some credit in saving the world though. Hehee.

[reactive]

I just wear and uv rash guard and I don't have much trouble with sunburn.

[ratown]

Ya, I have a quicksilver one, but I still need a little protection on my face if I am out for more than 4 hours.

[frogman159]

Originally Posted by Murloc

I thought it was necessary for there to be a constant flow of water movement over coral for it to survive...or am I wrong?

Your absolutely right. Depnds on the coral though, its more imperative for many soft corals to have higher current, some hard corals can get by with less.

This is from my aquarium keping days

[ratown]

Some coral does need more flow than others, but stagnant water probably isn't ever good.

[FriscoRays]

Originally Posted by *Merlin*

I read a magazine article about sun block that kills coral. The article suggested using sun block that contained zinc and a couple other active ingredients but it did not mention any products by name. Can anyone assist me with a coral friendly sun block?

Smartshield

Caribbean Sol

Cactus juice

UV Natural

Kiss my face

Mexitan