Scientists recently challenged the government to urgently address an unprecedented, catastrophic harmful algal bloom ravaging waters in South Australia, the Guardian reported.

What's happening?

Harmful algal blooms (HABs) are aptly named, caused by an overgrowth of algae, often of the toxic variety.

According to the National Oceanic and Atmospheric Administration, the precise confluence of circumstances behind a harmful algal bloom has yet to be identified. 

Changes to nutrient balances, ambient pollution, food chain fluctuations, invasive species, rerouted water flow, and an overheating planet "all play a role" in causing HABs.

The toxic algal bloom affecting Australia's waters was first identified back in March, and officials cited unusually high sea surface temperatures as an exacerbating factor. By July, the HAB had grown to over 4,500 square kilometers, or over 48 billion square feet.

South Australian Premier Peter Malinauskas said that over "400 different species of marine life" have been killed off or "had deaths" due to the HAB.

On July 24, Australia's Biodiversity Council published a report about the ongoing situation in Australia. The coalition of experts didn't mince words and challenged governments to act.

"Australia is witnessing one of the worst marine disasters in living memory," they began, warning of consequences "devastating [to] marine life" as well as the nation's "most iconic and economically important ecosystems."

Why is Australia's algal bloom so concerning?

As the report continued, its authors were forthright, refusing to sugarcoat the scope of the disaster or its known causes. 

The bloom "was [foreseeable] and even predicted," they explained, before cataloguing several likely causative conditions. 

"It is a human-mediated disaster — enabled by an extended marine heat wave, likely fed by a large pulse of nutrient-rich floodwater and coastal upwelling, and exacerbated by widespread loss of marine ecosystems that once provided natural water filtering and resilience against natural as well as human threats," they said.

In other words, while the exact causes for algal blooms have yet to be firmly established, scientists have a pretty good idea of why this one occurred and how it could have been avoided. 

As the Biodiversity Council explained, harmful algal blooms aren't just unsightly and unpleasant — a NOAA review after a "record-breaking" HAB on the West Coast of the United States in 2015 sought to quantify their effects on people who live in coastal communities.

Economic losses were a major consequence, followed by concordant job losses. Food insecurity resulted from HABs in communities that rely on the sea for sustenance. Cultural and spiritual activities were disrupted, and "community identity and social interactions" suffered, too.

What's being done about it?

In their report, the Biodiversity Council asked governments to commit to seven direct actions "to respond to this event and to prepare for an increasingly dangerous and unstable future."

The governments of Australia and South Australia allocated 28 million Australian dollars ($18.4 million) to research and remediate the algal bloom.

Previously, funds were made available to small businesses and fisheries in South Australia that were adversely impacted by the HAB.

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