Eddy Rises

It was reported a few days ago that a "giant ocean eddy" has formed off the coast of Australia, and it now "shadows Sydney." It's nearly 300km wide. The oceanic vortex "completes a full revolution every 10 days and the sea level at its centre is reduced by nearly 1m, which is how researchers can tell where the eddy is.” It is now "an ocean feature approaching the size of Tasmania."

[Image: An illustration for Edgar Allan Poe's Descent into the Maelstrom, by Harry Clarke].

Unfortunately, the eddy is "dissipating" – but it might yet turn into something else.
After all, the eddy has an aqueous antecedent: "A mysterious, huge and dense mass of cold water is milling off the coast of Sydney," we were told by a reporter for Cosmos, back in March 2007. The eddy is "baffling researchers and delighting fishermen" – and sowing the seeds of what has become today's hyper-eddy.
And last year's eddy was already huge. As Giles Foden wrote in the Guardian, it "carrie[d] more water than 250 Amazon rivers."
Inspired, Foden cites Edgar Allan Poe:

The edge of the whirl was represented by a broad belt of gleaming spray; but no particle of this slipped into the mouth of the terrific funnel, whose interior, as far as the eye could fathom it, was a smooth, shining, and jet-black wall of water, inclined to the horizon at an angle of some forty-five degrees, speeding dizzily round and round with a swaying and sweltering motion, and sending forth to the winds an appalling voice, half shriek, half roar...

"While they cannot be described as a freak of nature," Foden continues, "eddies as large as that discovered off Sydney can play a significant part in unexpected climate events" – and that brings us back yet another year, to 2006, for more news of weird vortices off the coast of Australia.
Moving to the other side of the continent, we find a "death trap" at sea:

A massive ocean vortex discovered off the West Australian coast is acting as a "death trap" by sucking in huge amounts of fish larvae and could affect the surrounding climate.

A scientist who visited the site "said the climate above the vortex was noticeably different. 'It feels like you're in the tropics,' she said. 'It's warm, soft, moist air, with flying fish, it's a very different environment.'"
And I love this:

"We were in a 70-metre boat and you could immediately feel the shift in the ship's tract, so you can certainly tell that there's something unusual going on out there," she said.

Spontaneous misdirection at sea.
So could that "something unusual" be repeated elsewhere? And though I mean naturally, perhaps it could even be done artificially: a vast stirring operation at sea, brought to you by Boeing... In fact, I'm tempted to pitch a science fiction film: a huge eddy forms off the coast of Manhattan, stirring up deep currents of sludge and dumped trash from the 1970s. The waters turn thick. Syringes and other forms of medical waste re-appear. The beaches of Long Island are closed. And then strange blood infections hit the local fishermen.
And then the fishermen begin to change... as the eddy drifts closer to shore.
Or, for that matter, set the film in San Francisco.
Cloverfield 2.

(Thanks to Alexis Madrigal for the tip!)