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Cambodia’s reefs thrive as rest of the world’s corals bleach

Marine biologists have just announced the fourth planet-wide coral bleaching event. Despite this devastating news, scientists are pleased to witness reefs off the coast of Cambodia thriving in warmer waters.

Coral reefs are often considered one of nature’s most magnificent creations. They are colourful ecosystems bustling with life, leading them to be dubbed the ‘rainforests of the sea’.

Despite offering a habitat, feeding ground, and breeding space for one-quarter of all marine species, corals themselves are extremely fragile. They’ve faced significant decline since the 1950s, with the primary culprit being warmer ocean temperatures – a consequence of human-induced climate change.

According to the National Oceanic and Atmospheric Administration’s Coral Reef Watch, at least 54 percent of our planet’s oceans have already endured heat stress significant enough to trigger coral bleaching.

Bleaching – a process that happens when corals become stressed and expel nutrients they rely on to survive –  threatens the future existence of these vital and delicate underwater ecosystems.

Announcing the fourth global bleaching event this week, scientists point out that these occurrences continue to increase in frequency over time, with the first documented in 1998. They now warn that the percentage of reef areas experiencing heat stress is climbing by approximately 1 percent every week.

To classify as a global bleaching event, a minimum of 12 percent of corals in each of our world’s oceans must undergo bleaching-level heat stress within a single year. This might not sound like much, but coral reefs cover a mere 1 percent of the planet’s ocean floors.

While this news doesn’t exactly paint a pretty picture, there is a reason to have hope.

Some coral reefs, like those found in East Asia, are thriving – specifically off the coast of Cambodia. Unlike species that make up reefs in the Atlantic, Indian, and Pacific Ocean, Cambodia’s offshore corals are multiplying like never before.

Researchers keeping a keen eye on these reefs believe the key to their survival lies in the diversity of species and their genetic makeup. It’s highly possible that this diversity has enabled the corals to build up a natural resistance to elevated sea surface temperatures.

The good news is that their offspring of heat-tolerant parents inherit this resilience, presenting an important opportunity for coral reef conservation efforts. Harnessing these coral’s heat-resistant qualities will be essential for restoring deteriorating reef ecosystems worldwide.

Efforts are already underway on this front, with researchers looking into heat-tolerant corals and cooperating with reef restoration groups on planting them in various oceans around the world.

In the end, East Asia’s coral reefs are an incredible symbol of nature’s ability to adapt and endure the pressures we humans have placed on it. Still, preserving and nurturing reefs of the future – man-made or not – will require that society’s planet-warming activities come to a halt as soon as possible.