Australia’s Algal Bloom Declared ‘Natural Disaster’: What’s Behind The Toxic Sea Crisis?

Last Updated:July 22, 2025, 21:26 IST

A massive algal bloom off South Australia's coast has turned the sea toxic, killing over 400 marine species and devastating local industries.

South Australian Premier Peter Malinauskas declared a massive algal bloom a natural disaster.

A massive algal bloom off the South Australian coast has turned vast stretches of sea into a toxic green soup, killing marine life by the thousands and devastating local industries. Here’s what we know.

What Is An Algal Bloom?

An algal bloom is a rapid and often toxic increase in algae population in a water body. While algae are a natural part of marine ecosystems, in excessive quantities they can deplete oxygen, block sunlight and release toxins- thus turning the water harmful for both marine creatures and humans. In this case, the algal bloom stretches from Coorong to the Yorke Peninsula, spanning an area twice the size of the Australian Capital Territory.

How Bad Is The Crisis In Australia?

So far, the bloom has reportedly killed over 400 species of marine life, including large numbers of fish, shellfish and other coastal organisms. Beaches have been lined with rotting carcasses and the normally pristine waters have taken on a sickly green hue.

What’s Causing Algal Bloom In Australia?

Experts have said that the crisis is being driven by climate change, which has led to a combination of rising sea temperatures, excess nutrient runoff from agriculture and urban sources as well as prolonged drought conditions. These factors have created ideal conditions for algae to multiply rapidly.

Is The Algal Bloom In Australia Officially A Natural Disaster?

Yes, at the state level. South Australian Premier Peter Malinauskas declared the bloom a “natural disaster" and criticized the federal government for hesitating to do the same. He said, “This is a natural disaster and should be acknowledged as such. I think politicians do themselves a disservice when they get caught up in technicalities."

The federal government has committed AUD $14 million for relief- including clean-up, research and support for affected industries. The South Australian government matched that funding, bringing the total response package to AUD $28 million. However, federal Environment Minister Murray Watt has so far refused to classify the event as a natural disaster.

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News world Australia’s Algal Bloom Declared ‘Natural Disaster’: What’s Behind The Toxic Sea Crisis?