It sounds like a harebrained idea from some whacky movie: Seaweed overgrowing the reefs? Why not just suck it up with a vacuum?

But a team in Hawaii is using a device dubbed the Super Sucker to do just that, and new results presented at the in Fort Lauderdale, Florida, suggest it might work.

Around the globe, the explosive growth of invasive and native seaweed species is wreaking economic and ecological damage. The Super Sucker was developed as a potential solution to the problem, which is blamed on overexploitation of algae-grazing fish and pollution from fertilisers.

To create the Super Sucker, biologists modified a system designed for gold dredging. Seaweed from reefs is sucked up and dumped onto mesh sorting tables on a barge. Native organisms inadvertently vacuumed are removed and returned to the reef and the seaweed is eventually used by farmers as fertiliser.

Grazed clean?

Eric Conklin, a marine science advisor for the in Honolulu, Hawaii, US, and project leader says that the team has cleared some 8,000 kilograms of algae – mainly the invasive Gracilaria salicornia – from two 210-square-meter reef plots, leaving a control plot in between.

The researchers could only remove about 90% of the seaweed, so they expected that the algae would grow back, necessitating periodic cleaning. Instead, within weeks, the remaining seaweed was gone and two years later it has still not returned.

“I was flat-out amazed,” says Conklin. The group’s theory is that they removed enough material that herbivorous fish could finish the job.

Conklin says Super Sucker would have to be coupled with other efforts to manage all reef problems. , a macroalgae specialist at the Harbor Branch Oceanographic Institute in Fort Pierce, Florida, US, agrees. “It’s great that they are doing this,” he says, “but there needs to be several approaches.”

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