The 2000 Hollywood thriller What Lies Beneath might not have been Robert Zemeckis’ finest work — a few cheap jump scares, quickly forgotten.

But the real horror playing out beneath South Australia’s normally pristine waters is far from fiction. It’s truly terrifying.

Aside from the COVID-19 pandemic, it’s hard to recall a crisis in our state of this scale and gravity.

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A kilometres-long stretch of coastline is blanketed in thick brown foam and sludge.

Entire beaches — usually teeming with swimmers, walkers, frolicking dogs and kids building sandcastles — now sit empty (because, let’s face it, most of us are avoiding them like the plague).

But dive deeper and the true devastation emerges.

Below the surface, marine life is suffocating. Choking. Dying.

Our ocean has become an underwater graveyard. Marine ecosystems so devastated, any sign of recovery seems to be drifting further away by the day.

The images pouring into the Channel 7 newsroom in Adelaide are nothing short of heartbreaking.

Our cameras are documenting the carnage and South Australians are sending us more every single day.

Photos and videos of fish, dolphins, rays, crabs, penguins and even sharks washed up lifeless on our shores.

And don’t get me started on that poor fur seal found slumped gasping for air on the footpath in Brighton.

Was it was trying to flee rough seas or was it another casualty of the algal bloom?

We’re told it’s a natural event. We know it’s a disaster.

But somehow, in this case, one plus one doesn’t equal two. Canberra still refuses to formally declare this crisis a natural disaster.

The mind boggles. The blood boils and what about the South Australians whose livelihoods depend on the ocean? Our tourism operators, commercial fishers, fishmongers.

They’re not just watching the environment collapse, they’re feeling the financial impact. And they’re hurting.

Will it get worse? Will our beaches be off-limits this summer? Can we safely eat what’s left of the catch?

Will government inaction today haunt us tomorrow?

Past mismanagement, present crisis and a community demanding answers. What lies beneath? The truth, still buried.

7NEWS Adelaide will air a special bulletin on South Australia’s algae crisis tonight at 7pm.

Rosanna Mangiarelli is a 7NEWS Adelaide presenter.