Study Claims Sunscreen Killing Coral Reefs

[Sarah]

http://news.nationalgeographic.com/n...een-coral.html

I am very skeptical of this claim.

[hbh2oguard]

I agree! The ocean is way way too big that a little sunscreen wouldn't do much.

[swimmergrl]

I agree! The ocean is way way too big that a little sunscreen wouldn't do much.

Actually, I wouldn't be so sure. We tend to forget that there are 6 billion people on Earth, and little things done by many build up quickly.

"According to our experiment it is estimated that at least 25% of the amount applied is washed off during swimming and bathing, accounting for a potential
release of 4,000-6,000 tons year-1 in reef areas." (Danovaro 2008)

That doesn't sound like a little bit of sunscreen.

National Geographic is a decent source for scientific reporting, but I always like to go back to the source. The link to the study in .pdf is below.

I read through it, and both the research techniques and and findings sounds firm. Sunscreen has been found to be detrimental to fresh water environments, so it makes sense that it has negatives effects in marine environments. Most of the data in the news story is from the 12th page of the study, page 13 of the pdf.

http://www.ehponline.org/members/2008/10966/10966.pdf

The study isn't claiming the chemicals in the sunscreen are killing the coral directly. Thus, concentration (amount of chemicals vs. amount of water) doesn't really matter. What their study has found is that several of the chemicals in the sunscreen activate a dormant virus in the coral. (Actually, the zooxanthellae (algae)) Viruses have no way to replicate themselves, so they dig into a healthy host cell and use the replicating mechanisms in the cell. Since they don't have any stop coded into them, the cell just churns out new virus copies until it explodes and releases them into the environment, where they will do the same to the next algae cell they find. It is basically an algae flu or HIV/AIDS. Coral and the zooxanthellae have a symbiotic relationship. The coral is entirely dependent on the algae for nutrients, so when the algae die, the coral starves and dies. It is a very interesting, and very scary finding.

Seems like a really good reason to look into biodegradable sunscreen.

Rachel

[Sarah]

Hi Rachel,

I looked all over for the original study and tried a keyword search at the site to no avail, so thanks!

The question in my mind is is it the sunscreen from swimmers that is causing the problems with corals, or is it the fact that the areas where swimmers are likely to be in areas with denser urban populations and thus pollution.

Is there such a thing as biodegradable, non-toxic sunscreen that works? That would be interesting...

Thanks Rachel!

[hbh2oguard]

Sure there's about 6 billion people in the world but a lot of them don't go in the water. Of those that do go in, all don't wear sunscreen, and all aren't going in the water around coral reefs. Coral is pretty sensitive and can be damaged/killed by numerous things some of which can be attributed to human activity but I'm still not sold on sunscreen. There's about 330,000,000 cubic miles of ocean and I just don't see how sunscreen could be a factor. I could see how global warming, sediment, harbors, hotels, urbinization, boats....etc can kill the reefs. There are just too many factors that have to be accounted for to conclude sunscreen.

[Papa Bear]

The study was flawed! They put the sun screen in plastic bags and tied them around the coral! First the amount is 1000s of times more concentrated! Next plastic blocks UV which could effect the alga that grows in the coral polyp and feeds the coral! So please! Hbh is right on, with the dilution factor! There is like 62lbs of gold in a square mile of sea water! More gold then Sunscreen I bet, maybe it's the gold? Or how about all the chlorine in the Sodium chloride? That stuff will kill you!

[swimmergrl]

Sure there's about 6 billion people in the world but a lot of them don't go in the water. Of those that do go in, all don't wear sunscreen, and all aren't going in the water around coral reefs. Coral is pretty sensitive and can be damaged/killed by numerous things some of which can be attributed to human activity but I'm still not sold on sunscreen. There's about 330,000,000 cubic miles of ocean and I just don't see how sunscreen could be a factor. I could see how global warming, sediment, harbors, hotels, urbinization, boats....etc can kill the reefs. There are just too many factors that have to be accounted for to conclude sunscreen.

By saying there are 6 billion people on Earth, I wasn't implying that all go into the ocean, I was trying to point out that little things can become huge problems when population numbers are so huge. Coral reefs are of huge importance to many people who depend on their existence to survive.

"Coral reefs are...directly sustaining half a billion people (Moberg and Folke 1999; Wilkinson 2004)." (Danovaro 2008)

Much like heavy metals, they build up in the environment, and can reach dangerous levels.

"Being lipophilic, sunscreen UV filters have the potential to bioaccumulate in aquatic animals (Giokas et al. 2007)" (Danovaro 2008)

The study isn't claiming that sunscreen is the only thing endangering coral, but that doesn't mean it doesn't have a part.

If you start reading at page 6 of the study, page 7 of the pdf, it tells you that they experimented with live coral samples from different areas of the world. They took healthy live samples, washed them in virus free water, put them in water tight bags filled with 2 liters of virus free water, then put them back where they were collected. They tested with multiple species from multiple areas of the world, and had several controls for each group. They tested different concentrations. The lowest being 10 microliters of chemicals per liter of water and the most being 100 microliters per liter of water. That is 0.00001 L of sunscreen per 1 L of water to 0.0001 L of sunscreen per 1 L of water. That isn't much at all.

If you go down to page 12 of the study, 13 of the pdf, you will find the area where they did experiments to calculate the amount sunscreen released into coral reef areas.

"We consider a conservative measure of two daily application per tourist on 5 day average tourist package, and a rough estimate of 78 million of tourists year-1 in areas hosting reefs (10% world tourist registered in 2004, UNWTO). Based on this calculation and on annual production of UV filters, between 16,000 and 25,000 tons of sunscreens are expected to be used in tropical
countries. According to our experiment it is estimated that at least 25% of the amount applied is washed off during swimming and bathing, accounting for a potential release of 4,000-6,000 tons year-1 in reef areas. Since 90% of tourists are expected to be concentrated in ca. 10% of the total reef areas, we estimated that up to 10% of the world reefs is potentially threatened by sunscreen- induced coral bleaching." (Danovaro 2008)

On page 13 of the study, page 14 of the pdf, they explain the results.

"In all replicates and at all sampling sites, sunscreen addition even in very low
quantities (i.e., 10 μl.L-1) resulted in the release of large amounts of coral mucous (composed of zooxanthellae and coral tissue) within 18-48 h, and complete bleaching of hard corals within 96 h (Figure 1, Table 1)." (Danovaro 2008). (10 μl.L-1 = 0.00001 L of sunscreen per 1 L of water).

"Conclusions: We conclude that sunscreens, by promoting viral infection, can
potentially play an important role in coral bleaching in areas prone to high levels of recreational use by humans." (Danovaro 2008)

The problem really lies in the fact that there is a heavy concentration of contamination at coral areas, because those are exciting places to swim, snorkel, and scuba dive. Other factors threatening coral include climate change, pollution from industry, recreation, and cities, and agriculture. Physical damage from tourists and commercial fishing, and overfishing. Everything combined is the problem, and sunscreen is just turning out to be one more part.


Hope that helps clarify the study contents a little.

Rachel

P.S.- iDiveChick, I couldn't find it through a Google search, so I looked up the journal it was published, then searched for the author.

[hbh2oguard]

The study was flawed! They put the sun screen in plastic bags and tied them around the coral! First the amount is 1000s of times more concentrated! Next plastic blocks UV which could effect the alga that grows in the coral polyp and feeds the coral! So please! Hbh is right on, with the dilution factor! There is like 62lbs of gold in a square mile of sea water! More gold then Sunscreen I bet, maybe it's the gold? Or how about all the chlorine in the Sodium chloride? That stuff will kill you!

I fully agree, except with the gold thing. It's kind of funny because I was just give some numbers in an oceanography class last week that I'm.

Element//////////////////Conc.(lbs/10^6 gal) /////////////////// $/10^6 gal

Cl ////////////////////// 166,000 lbs //////////////////////////// $33,000
Mg //////////////////////// 11,800lbs ///////////////////////////// $21,000
Al /////////////////////// 0.09lbs //////////////////////////////// $ .25
Cu /////////////////////// 0.03lbs ///////////////////////////////// $ .12
Au(gold) ////////////// 0.00004 ///////////////////////////////// $ .57


By the way Papa, how did the harbor clean up go? I talked to my normal dive buddy in So. CA the day before it and he said viz was expected to be basically nothing. I'm assuming it was nice and stormy too???

[hbh2oguard]

never mind papa I saw your other report that you posted

[Papa Bear]

"We consider a conservative measure of two daily application per tourist on 5 day average tourist package, and a rough estimate of 78 million of tourists year-1 in areas hosting reefs (10% world tourist registered in 2004, UNWTO). Based on this calculation and on annual production of UV filters, between 16,000 and 25,000 tons of sunscreens are expected to be used in tropical
countries. According to our experiment it is estimated that at least 25% of the amount applied is washed off during swimming and bathing, accounting for a potential release of 4,000-6,000 tons year-1 in reef areas. Since 90% of tourists are expected to be concentrated in ca. 10% of the total reef areas, we estimated that up to 10% of the world reefs is potentially threatened by sunscreen- induced coral bleaching." (Danovaro 2008)

On page 13 of the study, page 14 of the pdf, they explain the results.

"In all replicates and at all sampling sites, sunscreen addition even in very low
quantities (i.e., 10 μl.L-1) resulted in the release of large amounts of coral mucous (composed of zooxanthellae and coral tissue) within 18-48 h, and complete bleaching of hard corals within 96 h (Figure 1, Table 1)." (Danovaro 2008). (10 μl.L-1 = 0.00001 L of sunscreen per 1 L of water).

"Conclusions: We conclude that sunscreens, by promoting viral infection, can
potentially play an important role in coral bleaching in areas prone to high levels of recreational use by humans." (Danovaro 2008)

The problem really lies in the fact that there is a heavy concentration of contamination at coral areas, because those are exciting places to swim, snorkel, and scuba dive. Other factors threatening coral include climate change, pollution from industry, recreation, and cities, and agriculture. Physical damage from tourists and commercial fishing, and overfishing. Everything combined is the problem, and sunscreen is just turning out to be one more part.

I don't buy the primes! The idea that 25% of Sun Blockers are washed of has no factual evidence! "90% in CA" I am still looking for the coral reefs in CA! Please! Math is wrong, assumptions are made, bad science, and dad testing methods! These so called Scientists should get an "F" on there report cards!

BTW Coral reefs are doing fine and there is NO evidence that there is any extraordinary climate change! US industry does not pollute coral reefs! Recreation also does not damage coral reefs unless you walk on it! Not a lot of commercial fishing is done on reef structures it destroys nets and equipment as well! I think you need to get out from behind your computer and find out the truth for yourself! Your facts are just not true!