What’s that seaweed washed up on the beach?
Many residents, visitors and boaties at Wyndham Harbour have noticed the dark red mass that appears from time to time on the foreshore. What is it and where does it come from?
Lying on the seafloor at 5-10 m depth in the north and northwest of Port Phillip Bay, is a massive, moving underwater forest of ‘drift’ algae. It’s called ‘drift’ because it is made up of algae that aren’t attached to the bottom, and rolls along in great clumps like seafloor tumbleweeds.
Most of the time it is out-of-sight and out-of-mind, but when the wind and currents work together, it washes up in vast amounts on the bay’s beaches. Trapped in the hot sun, it rapidly becomes an enormous composting heap, breaking down to leave a sludgy, stinky mess. The drift is non-toxic. It’s an entirely natural phenomenon, but councils around the bay spend a lot of time and money clearing it off beaches to reduce the smell and improve beach amenity. Brighton and St Kilda Beaches get it in a westerly wind, Eastern Beach Geelong and St Leonards on the Bellarine Peninsula, Altona, Point Cook, Campbell’s Cove and all across the Werribee South Beach is the result of an easterly wind.
Above picture: Werribee South Beach, taken 02/03/18 at 10.07am
Wyndham Harbour is no different and gets its fair share of drift washing up on our foreshore, particularly when winds blow from the east or north-east.
What can be done about it?
The National Centre for Coasts and Climate at the University of Melbourne has looked into the drift problem over the past few years. We now know that there are vast amounts on the bay’s floor in summer when almost 2.5 million tons rolls around. What lands on beaches is just a very small tip of the iceberg of what lies beneath the surface. The drift will always be there, so what can be done about it? The drift is made up of more than 20 different species of green, brown and red seaweeds, many of which we already use. The drift contains a lot of the green seaweed Ulva, or sea lettuce, which many of us know and enjoy as nori, the green seaweed wrapped around our sushi rolls. The dark red colour comes mostly from Gracilaria, which is a red seaweed used to make agar, something that can be found in products as diverse as ice cream, toothpaste and food for abalone. Another red seaweed, Botryocladia, has compounds that are powerful anti-coagulants or blood clotting agents that with further research could prove useful for medicine.
What is Wyndham Harbour doing?
Together with the owners’ corporation, we purchased a boom to keep the drift out.
However, this was not an option supported by the waterway authorities due to the potential shipping and navigation hazard caused if it broke away. We’ve also tried to suck it up and move it around, but with no success. During this time, Wyndham Harbour has sought assistance from experts in this field including representatives from Parks Victoria (the waterway manager), Department of Environment, Land, Water and Planning, Prof. Steve Swearer, Assoc. Prof. Tim Dempster and Juan Manuel Valero Rodriquez from the National Centre for Coasts and Climate at the University of Melbourne, and the Wyndham City Council.
Recently, we’ve received final approval to build an access ramp to enable us to use equipment to maintain the area. In the future, we might see innovative solutions to collect the drift algae from beaches and put it towards alternative good uses. For the time being, Wyndham Harbour is trying different methods as we continue to maintain this coastline for all to enjoy.
Wyndham Harbour acknowledges the assistance of Prof. Steve Swearer, Assoc. Prof. Tim Dempster and Juan Manuel Valero Rodriquez from the National Centre for Coasts and Climate at the University of Melbourne for assistance and helping to create this communication.