Rottnest moorings ‘release ancient CO2’


Image supplied by the ECU research team

Research conducted by ECU scientists has found that boat moorings on Rottnest Island are causing seagrass meadows to release ancient Carbon Dioxide into the atmosphere, scarring and damaging the vital  ecosystem.

The research, conducted by ECU’s Dr Oscar Serrano, Professor Paul Lavery and Professor Pere Masque, looked at how mooring chains are “scarring” seagrass.

Not only is seagrass a home and food source to animal wildlife, it is also a crucuial absorber of carbon dioxide.

According to Dr Serrano, as seagrass dies, atmospheric carbon dioxide increases.

“When the seagrass meadows are wiped out the carbon dioxide which has been absorbed over hundreds of years, is released back into the atmosphere,” he said.

Old chain moorings drag along seagrass on the seafloor, cutting and killing it. With continuous use of the moorings, the seagrass cannot grow back.

“As moored boats drift with the currents, wind and waves they drag a heavy chain across the seafloor and that chain acts just like a razor across the skin removing the seagrass,” he said.

“There are other more environmentally friendly moorings that have a lower impact on the seagrass meadows,” Dr Serrano told ECU Daily.

“It is basically a pin with a chain that goes directly from the sea bottom to the surface, so there is no loose chain around the sea floor.”

According to Dr Serrano, the Rottnest Island Authority is aware of the problem, and they have been replacing some of the moorings with more friendly alternatives.

Although the studies were conducted at Rottnest Island, Dr Serrano says “this is a world-wide problem” that needs to be addressed.

Lake Macquarie, in the Hunter Region of New South Wales, has also had issues with boat moorings killing seagrass.

The NSW government has facilitated a rebate scheme, to encourage a change to more environmentally friendly moorings.

The 50% rebate allows mooring owners to switch to seagrass friendly moorings.

Brian Hughes, estuary and marine officer at Hunter Local Land Services, is a big fan of the rebate, and the introduction of new, chain free, moorings at Lake Macquarie.

“We think environmentally-friendly moorings are a great idea because they can help rehabilitate important marine habitats, especially seagrass,” Mr Hughes told ABC.