For many people, particularly those living in the Northern Hemisphere, coral bleaching may seem like one of those things that's only happening in distant lands that they'll never visit. The truth is, however, that's no longer the case. A recent study has recorded significant coral bleaching in what is likely Hawaii's most popular snorkelling area, Hanauma Bay Nature Preserve on the island of Oahu.
Led by Dr. Paul Jokiel (who passed away last April), a team from the Coral Reef Ecology Lab at the Hawai'i Institute of Marine Biology conducted surveys of the state-protected area from 2014 to 2016. Over that time, they observed that 47 percent of the flat reef corals bleached overall, and 9.8 percent of the corals died.
The scientists state that rising ocean temperatures caused by global warming are the culprit. This finding is supported by the fact that the bleaching is worse in parts of the bay where the water is able to pool and get warm, while it's less pronounced in areas where fresh, cooler water from the ocean is able to surge in and out.
Coral bleaching occurs when environmental factors cause corals to expel the algae that lives within their tissue. This causes the corals to starve and subsequently die. Unfortunately, it doesn't look like the situation in Oahu is going to improve anytime soon.
"Warmer seawater temperatures are again predicted for the Hawaiian Islands in 2017 with the grave possibility of more coral bleaching and mortality", says Dr. Keisha Bahr.
Source: PeerJ