Forests of the future

How seaweeds are paving the way for a blue revolution.

At first glance, seaweeds may not appear futuristic, but they hold the key to restoring marine habitats and could form the basis of hi-tech industries for Tasmania and beyond.

When alumnus Dr Cayne Layton (PhD 2018) first scuba- dived at Fortescue Bay on the Tasman Peninsula on holidays from the mainland in 2010, he marvelled at the region’s giant kelp forests. He would remember the way the light filtered through, illuminating rich ecosystems of lobsters, crayfish and endemic species such as the leafy seadragon.

“There was the feeling of being very small, like being in a fish tank, with kelp that was 10, 20 and 30 metres tall,” said Cayne, who went on to do his PhD on the more common ‘golden kelp’ through the University of Tasmania’s Institute for Marine and Antarctic Studies (IMAS). Just a handful of years after that first encounter, when Cayne returned for his PhD, he found the giant kelp forests had dwindled, and just 18 months into his field work they were gone from Fortescue. The reason was an increase in warmer, nutrient-poor waters from the East Australian Current reaching Tasmania as a result of climate change.

When Cayne’s PhD supervisor, marine ecologist Professor Craig Johnson (BSc 1980 Hons), was a university student in Tasmania, the giant kelp forests were even more extensive. Craig’s mapping research has shown a decline of more than 95 per cent along the State’s East Coast in recent decades.

But there is help at hand, with new research by Cayne and Craig finding naturally occurring warm-tolerant strains of giant kelp. These strains of ‘super kelp’ have been successfully raised in the IMAS laboratory and planted out in areas where giant kelp once grew.

“The restoration is looking good,” Craig said.

“The warm-tolerant kelp we’re putting back into the wild are thriving. We’ve just had a really warm summer and all the native ones were bleached and necrotic, and all ours were well-pigmented and looking very healthy.”

Cayne, who is now a postdoctoral researcher on the restoration research, has experimented with growing kelp on the outside of salmon pens. Giant kelp planted as millimetre-long ‘seedlings’ (micro-sporophytes) had grown to 10 metres-long within about a year.

There is hope too that seaweeds – from microscopic algae to giant kelp – will be the basis of new high-tech, high-value seaweed industries and products. With the start of two Cooperative Research Centres (CRC), the Blue Economy CRC and the Marine Bioproducts CRC, Craig said there is “huge potential for a seaweed industry to develop in Australia”.

IMAS Professor Catriona Macleod (PhD 2006), leader of the Sustainable Marine Resources program of the Marine Bioproducts CRC, is overseeing research to develop seaweed culture programs that will optimise the production of a range of species, but particularly microalgae and macroalgae.

“Already we have demonstrated that we can grow commercial quantities of seaweed in Tasmania, and we know that there are existing markets for this – everything from ice cream to burn dressings, from face cream to fertiliser, and of course a whole range of nutritional food products. And those are just the products we know about,” Catriona said.

“There is a whole suite of innovative products, really novel blue-sky applications such as bioplastics and fireresistant building materials, that need more research.

Giant kelp forests along Tasmania’s east coast have decreased by 95 per cent in recent decades largely due to an influx of warmer seawater as a result of climate change. Photo: Matthew Doggett

It’s quite exciting to be part of research underpinning an important new industry for Tasmania that has very strong environmental benefits.”

Professor Craig Johnson

“Seaweeds have also been shown to limit methane production in cattle, and there’s a lot of interest in the potential for seaweeds to draw down carbon to help with environmental management and climate change. These are all really exciting research areas that will involve a very broad team at the University, from seaweed and aquaculture specialists, to chemists, nutritionists, engineers and even designers.”

And for giant kelp, it is hoped that not only will the forests of the sea be restored at several sites along Tasmania’s coastline, but the species could be commercially grown to make many of the products described. For example, giant kelp shows real promise as a potential candidate for bioplastics that are nontoxic, biodegradable, and compostable at ambient temperature.

“It’s quite exciting to be part of research underpinning an important new industry for Tasmania that has very strong environmental benefits,” Craig said.

Katherine Johnson

Dr Cayne Layton checking giant kelp cultures in the University’s Institute for Marine and Antarctic Studies laboratory.