Mermaid hair or plant life?

As the tide goes out at Yurong Point in Port Jackson, the edges of the platform appear to be covered in mermaid hair. Discover what these luscious brown locks really are with Honorary Research Associate at the Royal Botanic Garden Sydney, Dr Stephen Skinner.  

No, the Port Jackson water sprites haven't set up a beauty salon for local mermaids. This hair-like material growing at Yurong Point in Port Jackson is in fact a brown alga called Acinetospora crinita (Carmichael) Sauvageau.

Dr Skinner said A. crinita is quite common in temperate parts of the Pacific and other oceans. ​

"Brown algal blooms are not uncommon in spring, especially after a flush of nutrients following sudden, heavy rain," said Dr Skinner. 

"This time the interwoven filaments have provided an interesting oddity. It may very well vanish as suddenly as it has appeared," said Dr Skinner. 

Algae have been estimated to include anything from 30,000 to more than 1 million species (Guiry, 2012). While some algal blooms can cause problems, A. crinita and other algae are important as they form the basis of marine food webs and produce oxygen. 

"A. crinita can be something of an eyesore and it really isn’t much fun body surfing in brown cotton wool, but apart form that it's not a cause for any concern here," said Dr Skinner. 
 

Dive deeper... 

Acinetospora crinita is one of four species in the genus Acinetospora, which belongs to the family Acinetosporaceae in the order Ectocarpales. The family contains the more commonly recognized cotton wool algae, Feldmannia, Hincksia and Pyliaella.

Dr Skinner said A. crinita is poorly collected from New South Wales; the most recent collection being in 1971 from Nambucca Heads (Clayton, MELU21029).

"It is very likely that it is rather more widespread and common than this, but like the other brown cotton wool algae, unless it is a nuisance it is overlooked," said Dr Skinner.

"Its reproductive structures come in a range of sizes and the filament growth zones are scattered, twisting amongst one-another to form skeins.

"Interestingly, the new lateral branches of the filaments arise from the middle of the cell wall, not from the top," said Dr Skinner. 

Dr Skinner's work resarching freshwater algae in coastal and inland waters helps support the monitoring of our waterways and our understanding of plant diversity in NSW.