Could floating seaweed "sausage" farms be Queensland's next big industry?
A two-year trial led by the University of the Sunshine Coast and Urban Utilities has farmed 125 kilograms of seaweed — 10,000 sushi rolls worth — off the state's coast.
"No-one else has farmed seaweed off the coast of Queensland," USC biology professor Nick Paul said.
"We had to start right at the beginning, working out what species are there, very small-scale collections of seaweed."
Those collections were then tested in a lab before they were sent out to a Moreton Bay oyster farm, where researchers discovered sausage-shaped nets were the best way to grow seaweed there.
Why oyster farms?
Firstly, the infrastructure is already there, so it's just a matter of attaching the sausage nets.
Oyster farmers are also keen to diversify, Professor Paul said.
"It's quite tough to grow oysters, it takes around about three years.
"With climate change and increasing water temperatures there's a lot more risk of operation around disease, so they were really keen to see if they could diversify into other products and seaweed is really compatible with oyster farming."
Seaweed was found to increase oxygen in the water, which is a win for the oysters and those who farm them.
Every year 30 million tonnes of seaweed is produced worldwide, and AgriFutures Australia said the country had the potential for a $1.5 billion industry within the next 20 years.
And it isn't all going into sushi.
"We know that seaweed can be fed to cattle, there's even people exploring its use in sustainable packaging," Professor Paul said.
Seaweed is also great at keeping the balance of nutrients in our waterways in check, the trial found.
"Seaweed is really good at removing nutrients from the water, they strip it out as they're growing," Professor Paul said.
"For every tonne of wet seaweed that we're pulling from the bay, we're pulling out about 1.5kg of nitrogen as well."
Anna Hartley from Urban Utilities said that could be handy as our population grows.
"As more people call our region home, we're passionate about exploring clean, green and innovative ways to make sure the balance of nutrients in our environment remains just right."
What's next for seaweed farming?
Researchers have identified a handful of seaweed species that could be developed into full-scale production.
"There's an edible form called sea lettuce, another one is a seaweed that is used to extract agar which is a gelling agent," Professor Paul said.
"Then we found two brown seaweeds — which are the dominant ones off the coast here — grow really rapidly, form wonderful underwater forests and they're the species that we're hoping to work on afterwards."
But more research is needed to see if large-scale seaweed farms are viable.
Professor Paul said studies like this will lay the foundation for new projects.
"There's a whole wealth of opportunity here, we've got wonderful natural resources off the coast of Queensland and it's just the right time to tap into those."
