Corals killed by sunscreen?

[bubbles3d]

Everyone needs to be using the biodegradable as creamofwheat advised. When we snorkled w/ the whale sharks at Holbox Island that was mandatory or you were not allowed off the boat.

 

[Garrobo]

Maybe a few of the wacko ecologist wannabees around here haven't noticed that there's a lot of difference in the confines of a private or public aquarium and the open ocean. Fly over it sometime and maybe you'll get the picture.

 

[Blackrock]

The study may have been flawed but there's no reason to throw the baby out with the bathwater so to speak.

If there is even a chance that regular sunscreen might damage or kill coral then why not use coral-safe sunscreen. It's a minor adjustment for us as divers to make. It doesn't matter what your political preference/affiliation is --environmental issues affect us all. Nobody is asking for a huge sacrifice here.

 

[lmorin]

.......
Interesting that the 3 sunscreen ingredients I recommend ( 1. Titanium, 2. Zinc, and 3. Avobenzone) do not cause coral kills.

Apparently sunscreen can block the sun, and causes viral reactivation which kills the corals. I know that all sunscreen are supposedly banned in the mexican marine parks.

Having read the scientific article, I have a few comments. First, do not be so sure that your recommended sunscreens do not kill corals. They were not tested in the study. Second, do not be misled by the characterization of the substances as "sunscreens" into the belief that the chemicals, for that is what they are, are killing coral because they block the sun. They don't block the sun's rays, at least not all of them. The so-called sunscreens are fairly specific for UV wavelengths which are very short and not for longer wavelengths. Even among the sunscreens there is wavelength specificity with some blocking UVA and others blocking UVB wavelengths (UVA 400 to 320 nm; 320 to 290 nm for UVB). Most block UVB light, but do little or nothing to block UVA light.

The article indicates that viral release occurs in the damaged coral, but the why or the source are not known.

As to the worry by posters that this whole issue is nonsensical or simply wrong, you'll have to judge for yourselves after reading the paper. Let me point out, however, that most experiments in biology are done with control groups to specifically eliminate the possibility that such things as putting plastic bags over the coral colonies are not causing the observed effects. The published studies were no exception to this rule.

There were many different controls including corals that were just placed in the bags, corals that were placed in the bags with nutrient infusion, corals that were placed in the bags with various chemicals found in typical commercial sunscreen mixes but which are not themselves sunscreens (for example, the solvent propylene glycol). None of these control conditions caused coral bleaching and death, whereas treatment with the chemicals that are effective sunscreens did cause such death; all other conditions were equal.

To me, the weakest part of the studies was that which measured the amount of sunscreen transferred from body to water by a typical user. The investigators made chemical measurements of concentrations found in the water after a limb covered in sunscreen was bathed in 2 L seawater at 24oC for 20 min. The investigators estimate that 25% is "released in the water over the course of a 20-min submersion." They do not show their data or state how they arrived at this estimation. Then, to determine impact on reef systems, they make estimates about the total chemical release from an average body covered in sunscreen multiplied times the total number of bodies in reef areas and get an astonishing yield of 4,000 to 6,000 tons of sunscreen chemicals released from reef-visiting tourists per year.

I think others could recalculate these estimates and get vastly lower results using substantially different assumptions about sunscreen use (for example, divers who use sunscreen probably refrain from putting it over the entire body; even if they do, the body is typically covered with something that is likely to retard release of the sunscreen into the water). Nevertheless, chemicals in the water, even in very low concentrations, can be insidious and especially toxic to denizens who have evolved in the absence of man-made contaminants.

 

[creamofwheat]

OK! Cool ... Any brands you know of?

Yep...try Sun Protection - Biodegradable Sunscreen

 

[fisherdvm]

Yep...try Sun Protection - Biodegradable Sunscreen

Only thing that bothers me about "all natural products that has never been tested on animals" is that they never list the ingredients!

When you actually can obtain the ingredients through great difficulties, you frequently find that they contain quarternium 15, formaldehyde releaser, and other synthetic preservative, probably including butylparabens which is harmful to corals.

I don't buy the label .... Give me the ingredients. Then I'll believe you. When it is never tested on animals.... And you break out with zits..... Then you wished that it has been tested on animals.

Just remember, plastic is "biodegradable", but it takes sun light exposure.