If someone told you Australia had a forest that vanished in under a decade, you'd probably picture bushfire footage. You wouldn't picture the ocean.

But that's exactly what's happened off Tasmania's east coast, and it's why a small dive centre an hour south of Hobart has started training people to become, essentially, underwater gardeners.

So What Actually Happened to the Kelp?

Tasmania's giant kelp forests have declined by more than 95 per cent since the 1950s, and locals who dived these waters in the nineties describe an almost unrecognisable coastline. Mick Baron, who co-founded Eaglehawk Dive Centre in 1991, remembers a time when the kelp was so dense you couldn't drop a net or a pot in the middle of it. By the summer of 2015 to 2016, one of the region's largest forests had disappeared entirely.

The cause is a combination of the waters along Tasmania's east coast are warming three to four times faster than the global average, and with fewer predatory rock lobsters around to keep them in check, long-spined sea urchins have moved in and grazed the reefs bare.

Underwater Gardening Is Now a Real Job Title

Here's the part that made me sit up. Eaglehawk Dive Centre has just run its first live-in internship, where paying participants spend a month learning to hand-plant juvenile kelp using a technique developed by researchers at the University of Tasmania's Institute for Marine and Antarctic Studies. The kelp is grown on spools in a lab, then divers wrap it around the base of the reef at carefully chosen sites.

Six interns took part in the first intake, including 25 year old Masters student Linnea Bird, who travelled all the way from California. "Being able to go across the world and see very similar ecosystems, but also just different biodiversity, has really drawn me to Tasmania," she said. 

The interns' work has a name, "underwater gardening", which involves clearing about a metre of competing seaweed around each juvenile kelp so it has room to grow. It's slow, cold, unglamorous work. It's also already helped seed more than 800 kelp patches around the centre's home waters.

Why a Forest You'll Never Walk Through Matters

Giant kelp forests aren't just scenery for divers. They're nurseries and habitat for lobsters, abalone and scalefish, and they help buffer the coastline itself. The Tasmanian Giant Kelp Restoration Project, a partnership between The Nature Conservancy, IMAS, NRM South and CSIRO, is already using what's learned here to plan future restoration work in Victoria and South Australia.

Results so far have been what researchers call a mixed bag, since warm snaps and storms can undo months of work in a day. But when conditions line up, a kelp forest can regrow within a year.

Ready for another feel-good story? Check out our blog about Noosa's new community battery!

With Love, 
Ellie x

Frequently Asked Questions

What caused Tasmania's giant kelp forests to disappear?

A combination of rapidly warming coastal waters, up to three to four times the global average, and an explosion in long-spined sea urchins, which graze kelp down to bare rock once their natural predators, rock lobsters, are depleted.

How much of Tasmania's giant kelp forest has been lost?

Scientists estimate more than 95 per cent of Tasmania's giant kelp forests have disappeared since the 1950s, with some of the steepest losses happening within the last decade.

How does giant kelp restoration actually work?

Researchers grow juvenile kelp on spools in a laboratory, then divers hand-plant it by wrapping it around the base of the reef at selected sites, followed by "underwater gardening" to clear competing seaweed so the young kelp can establish.

Can everyday people get involved in restoring kelp forests?

Yes. Eaglehawk Dive Centre now runs a live-in internship program for trained divers, and also offers a PADI Giant Kelp Restoration Specialty course for recreational and technical divers who want to help plant and maintain the forest.

Will Tasmania's giant kelp forests fully recover?

It's too early to say. Results have been described as a mixed bag because storms and marine heatwaves can undo restoration work, but researchers say a forest can regrow within a year when conditions are favourable, and lessons from the project are already informing restoration efforts in Victoria and South Australia.