Journal Club Review – Ban the Block?

February’s journal club was lead by Grant Hisao (Postdoc in Biochemistry, Henzler-Wildman lab). Journal club review was written by Amanda Hurley (Postdoc in Jo Hanelsman’s lab).

A disturbing trend.

When the colorful, symbiotic algae living in coral is expelled during stress, the coral bleaches white. Since the little critters provide 90% of the coral’s energy, the bleached coral eventually starves to death. Historically, a mass coral reef bleaching event occurred every three decades, usually coinciding with increased temperatures during El Niño conditions. Currently, mass bleaching events occur every 5.9 years. The unsettling images of bone-white coral, when the reefs should be exploding with color and life, is becoming the “new normal.”

The main culprit for the death of coral reefs is climate change. The symbiosis between the algae and coral exists in a narrow temperature range so increasing temperatures leads to a break down in the relationship. The National Oceanic and Atmospheric Administration also sites runoff, pollution, overexposure to sunlight and extreme low tides leading to coral bleaching. In Wednesday’s journal club, CaSP investigated another potential source: sunblock. In 2017, Hawaii introduced bills in the Senate and House to ban the use oxybenzone sunscreen in marine life conservation districts. The fate of the bills is yet to be decided but it got us wondering: is this an effective policy?

The main chemicals (the organic chemicals) in sunblock are the carbon-rich oxybenzone and octinoxate. A 2016 article showed high concentrations of oxybenzone cause stunted growth in coral polyps (baby corals) in vitro and the expulsion of algae. However, in the same paper, testing for oxybenzone in sites around coastal Hawaii did not reveal alarming levels. In general, the CORAL-letions between oxybenzone and bleaching, just aren’t strong enough.

Back in Hawaii, the bills have stalled in the House and the Senate so local government in Maui decided to take action. Councilmember Elle Cochran proposed a moderately successful bill that at least passed committee: the ban of any sale or use of oxybenzone or octinoxate containing sunscreen. It now awaits a formal hearing.

The effectiveness and purpose of a sunscreen ban bill.

The county bill that addresses the sale of sunscreen would decidedly be easier to enforce, which raises the question: why even propose a toothless bill to block the “use” of sunscreen anyway? Secondly, why only block one type of chemical in sunscreen? As outside observers, labeling a single sunscreen as “bad” without testing competitors seems unfair and illogical. Especially with inconclusive data connecting oxybenzone with coral bleaching, what actual good would a bill like this accomplish?

A politician’s nightmare: we need more data.

As is, the current bills to block the use/sale of oxybenzone-containing sunscreen for the purpose of preventing coral reef bleaching seem half-baked. In fact, an earlier paper on this subject shows other sunscreen ingredients BESIDES oxybenzone are much worse for coral bleaching, although interestingly the bleaching effect differs in the same species collected from different oceans….and may be due to activation of lysogenic (dormant) viral infections of the algae! I’m quite aware the previous comment was a run-on sentence but I couldn’t help myself – that paper was awesome.

Recommendations for legislative action include:

  1. Verify sunscreen compounds to be banned actually cause coral bleaching.
  2. Test effectiveness of a sunscreen ban on pilot beaches by longitudinally tracking local coral reef health.
  3. Finally, propose a bill that can be enforced!