Beachcombing: Hunting for red tide with algae-seeking robots (photos)

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This story is part of our summer series "Beachcombing," in which KPCC reporters will explore  the ecology, economy and culture of Southern California's beaches and coast. Let us know what you think in the comments below or on KPCC's Facebook page. 

Sitting on a dock on Catalina Island is a 6-foot long torpedo.

Well, it's not actually a torpedo. It's a sophisticated seafaring robot that looks like a torpedo. Owned by the University of Southern California, it's designed to swim the ocean looking for signs of red tide. 

Red tide is naturally occurring phenomenon in which algae overpopulate a stretch of water, turning it red. Sometimes, these algal blooms produce harmful toxins that sicken sea creatures.

In recent years, red tide has poisoned large numbers of West Coast shellfish, costing the industry tens of millions of dollars in lost revenue. Sea lions, birds and, in rare cases, even humans have died from eating red tide-tainted seafood.

RELATED: Loss of isopods raises questions about beach health (photos)

USC biology professor David Caron says for years now it's been clear that harmful algae blooms are increasing worldwide.

He says some scientists think global warming is to blame. Others say runoff from farms and cities are draining into the ocean and feeding these micro-organisms, causing them to grow in large numbers.

"It's very complicated," Caron says, adding that the rise in red tide is likely due to a combination of factors.

Readying the robot

USC's red tide-hunting robot is named Rusalka. Technician Carl Oberg says the name comes from a Slavic legend.

"Rusalka is a water spirit that drags men down to their deaths," Oberg laughs.

Oberg tightens the seals on the robot, plugging in cables and getting the $120,000 robot ready for a two-week solo mission in the Pacific.

"When you are deploying something like this which is that expensive you have to make sure every single thing checks out correctly," says USC scientist Arvind Pereira.

Pereira programs the robot's path through the water. He uses complicated models to map the ocean and send Rusalka to places where red tide is likely to form.

Once there, the robot uses a suite of onboard censors to gather clues about the oceanic conditions that lead to red tide.

Underwater robots like Rusalka can sometimes detect harmful blooms as they are forming, says Professor Caron, allowing scientists  to warn people of potentially toxic conditions before they reach shore.

Caron says he hopes one day the data gathered by these robots will lead to ways of curbing the frequency and toxicity of red tide.

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