Be an underwater gardener this Christmas to help fix Sydney's marine bald patches

A diver working on the seaweed transplant. Image: Operation Crayweed.

Scientists have turned to crowdfunding to fund a huge project to replant seaweed forests off Sydney destroyed decades ago by sewage.

The University of NSW and the Sydney Institute of Marine Science have launched Operation Crayweed to encourage people to become underwater gardeners to restore seaweed which disappeared from the city’s coastline 30 years ago.

The disappearance of crayweed (Phyllospora comosa) is thought to be linked to the discharge of poorly treated sewage too close to Sydney’s beaches in the 1970s and 1980s.

Water quality has improved since the 1990s when deep ocean outfalls for sewage were built but the seaweed hasn’t returned.

After more than eight years of research, scientists have developed a method of transplanting fertile adult crayweed plants onto deforested areas.

The method implemented at three sites at Cape Banks, Little Bay and Long Bay has been so successful the researchers now want to bring crayweed back to 70km of coastline between Palm Beach and Cronulla.

A clip showing the seaweed off Sydney:

“Seaweeds are the trees of our oceans, providing habitat, food and shelter for other marine organisms,” says marine ecologist and crowdfunding campaign leader Dr Adriana Verges, from UNSW’s School of Biological, Earth and Environmental Sciences.

“When these forests disappear, it’s a sign that something has gone fundamentally wrong and diverse marine communities and economically important species such as rock lobsters and abalone disappear too.”

Seaweed off Sydney.

About 7000 individual plants are needed for the project. Each crayweed has to be tied to a biodegradable mesh fastened in place on reefs at two to three metres depth.

The researchers hope shoppers looking for sustainable gifts this Christmas will donate $20 to plant an underwater tree, $50 to create a little family unit of seaweed or $500 to plant a forest.

The end goal in this first stage of the crowdfunding campaign is to raise $20,000 via Pozible.

“It’s a perfect Christmas gift to the environment,” says campaign scientist Dr Alexandra Campbell. “We will also be approaching corporations to give larger amounts.”

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