Coral bleaching has impacted the ecosystem of the Great Barrier Reef and has now been detected in Sydney Harbour.

Sydney university researchers said the bleaching aligned with a rise in temperature due to an El Niño event and could not be directly linked to climate change. The UTS Climate Change Cluster’s Dr Matthew Nitschke said if the bleaching became a regular occurrence, it could be an indication of climate change.

“Because it’s the first time its happened and we’ve been getting really warm waters all down the eastern coast of Australia, this could be an indication of climate change but it’s still too early to tell,” Dr Nitschke said.

Coral bleaching happens when there are unusual environmental changes, such as extreme temperatures, that cause physiological stress in the marine invertebrate. The coral then dispels tiny photosynthetic algae that usually creates its vibrant colour.