Slathering up on sunscreen when we hit the beach or go swimming in the sea is something many people do in order to prevent sun damage. But these skincare products can be deadly for marine life forms like corals, studies have found.
Coral reefs are already at risk due to warming waters and pollutants. This year, a study by an Australian government agency has found that around 91% of reefs along the Great Barrier Reef have coral bleaching. This is the sixth mass bleaching event of the reef on record and the fourth since 2016. What is alarming is that almost every coral reef that was surveyed across the 2,300 kilometer system had been bleached.
Coral bleaching is a stress reaction where the symbiotic algae that live inside corals are expelled, resulting in starvation and disease.But it's not just warming waters that are a cause for concern. An everyday essential in skincare, sunscreens, are also causing much damage. Over the years, many studies have that sunscreens (and many other skincare products) affect corals and the fragile marine environments.
Scientists have labelled oxybenzones, an ingredient found in sunscreens, as dangerous to corals and marine life, leading to a ban on oxybenzone and other ingredients in countries like Hawaii, the Virgin Islands, Palau and Aruba. Incidentally, Thailand too has banned the use of sunscreen in all marine national parks in the country to contain coral-damaging chemicals.
Recently, Down To Earth reported that two environmental chemists studied the use of oxybenzone chemicals in sunscreens to analyse how oxybenzone impacted on sea anemones, which were taken as models for corals. Sea anemones and corals are classified under cnidaria, and have similar biological processes, such as a symbiotic relationship with algae. In the lab experiment, it showed that oxybenzone turned into phototoxins, which remain harmless in the dark but become toxic in sunlight. The scientists also found that turning oxybenzone into phototoxin was part of metabolic processes that any organism undergoes if it consumes a foreign substance. Furthermore, inside the anemone, the chemical structure in oxybenzone- a specific hydrogen on an alcohol group - was replaced by sugar. But oxybenzone is not a chemical that will become easier to excrete. Instead, it starts chemical reactions that damage cells.
When they conducted these experiments on mushroom corals, they found that the oxybenzone-turned-phototoxin got absorbed by the algae inside the coral tissue. As algae protect coral hosts from phototoxins, it is useful to know why coral bleaching is excessively harmful to coral life. As coral bleaching leads to the expulsion of algae, the phototoxins can easily get absorbed and make corals vulnerable to the deadly effect.
You might think that only people surrounded by coral reefs should worry about oxybenzone on their list. But everyone, including Indians, need to be careful of using sunscreen with oxybenzone in the ingredients list. As we dive into the beaches of Andaman and Nicobar or Lakshadweep islands, housing India’s coral reefs, we need to understand that each person’s harmful habits can lead to bigger adversities. These days, a few sunscreens are labeled as reef- safe, which removes oxybenzone from the ingredient list. But more research should be done on alternate chemicals that are used in ‘reef-safe’ sunscreens to truly protect marine life. It shouldn’t be that even the alternate chemicals mimic the previously banned chemicals.
