Sunscreen protects our skin, but coral reefs pay the price
Friday, October 23, 2015, 10:21 AM - A key ingredient found in sunscreen worn by ocean swimmers is causing irreversible damage to the world's coral reefs, according to a new study.
Divers entering the ocean waters to explore one of the greatest wonders of the natural world are taking measures to protect their skin from the sun's harmful ultraviolet rays, but at the same time, are unleashing harmful amounts of contaminants into the world's fragile underwater ecosystems.
Researchers have found that the chemical oxybenzone, a compound found in most sunscreen lotions and often labelled as Benzophenone-3, is toxic to young coral, causing DNA damage and death to the marine invertebrates.
Originally published in the journal Archives of Environmental Contamination and Toxicology, the study examined reefs in Hawaii and the U.S. Virgin Islands, with higher amounts of oxybenzone found in the Caribbean region.
Approximately between 4,000 to 6,000 tons of sunscreen enter coral reef areas around the world each year, according to the U.S. National Park Service, by means of swimmers and through the discharge of wastewater.
Coral reef lagoon at Shark Island, French Frigate Shoals, Hawaiian Islands National Wildlife Refuge.
Oxybenzone has also been found to exacerbate coral bleaching. Bleaching occurs when environmental triggers or stress cause coral to expel the algae that give them colour, causing the coral to take on a white, bleached appearance.
Corals can survive a bleaching event, but they are under more stress and are subject to mortality. If the algae loss is prolonged and the stress continues, coral eventually dies.
Warming ocean temperatures have been the leading cause of coral bleaching around the globe as coral can only live within a limited temperature range.
In 2005, the U.S. lost half of its coral reefs in the Caribbean in one year due to a massive bleaching event. The warm waters centered around the northern Antilles near the Virgin Islands and Puerto Rico expanded southward. A comparison of satellite data from the previous two decades confirmed that thermal stress from the 2005 event was greater than the previous 20 years combined.
The effects of oxybenzone are exacerbated by light, thereby contributing to bleaching in the warm, sunny regions where most coral reefs are found.
It is estimated that 90 per cent of snorkelers and divers are concentrated on 10 per cent of the world’s reefs, indicating that the most popular reefs are being exposed to the majority of sunscreen compounds in the water.
While researchers are not suggesting that people exploring the coral reefs do so without sun protection, there are alternate ways to protect your skin and the ocean environment.
To start, checking labels for actvie ingredients before buying sunscreen can help. Sunscreens made with titanium oxide or zinc oxide have not been found to harm reefs, according to the National Park Service.
Additionally, swimmers can cover their upper body with long sleeve shirts or other apparel in the water to reduce the use of sunscreen.
Coral reefs are among the most biologically diverse ecosystems in the world. Though they cover less than one per cent of the ocean’s floor, nearly one million species of fish, invertebrates, and algae are estimated to live in and around the world’s reefs.
About 60 per cent of coral reefs are at risk of being impacted by a variety of sources including marine pollutants, overfishing, boat groundings, disease and climate change.
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