Fresh Science

In a world-first, research has used sophisticated time-lapse video microscope techniques to watch the sex lives of red seaweed in action.

“Until now, no one knew what exactly happens when these seaweeds become sexy,” says University of Melbourne researcher, Dr Sarah Wilson.

“Despite the fact that red seaweed is worth hundreds of millions of dollars in the food processing industry for nori (sushi) and also to helps thicken foods like icecream, little is known about them,” she says. “Their reproductive biology has been studied for over a century, but mostly on dried or preserved seaweed.

“This is the first time we have observed their sex life in living cells.”

Dr Wilson will describe the discovery with the help of video footage at a Fresh Science media conference at the Melbourne Museum today (August 18).

“We found that some male red seaweeds will release millions of sperm when there is less salt in the water and at high tide,” Dr Wilson says. “The sperm travel on water currents to the female seaweed and attach to tiny hairs.  The sperm then inject their DNA into the hairs and fertilise the egg which is found at the base of each hair.”

Dr Wilson describes the first time she saw the sperm enter the female hairs as: “very beautiful – so precise and ordered. And it all happened at the microscope level where most of us never get to see it.

“Heaps of sperm land compete with each other to get to the egg at the bottom of each hair,” she says. “It’s a bit like watching a nightclub scene.”

The southeastern coast of Australia has the largest number of red algae species in the world, and they are found in every type of aquatic environment on earth.

Dr Wilson has won a “Science as Art” prize for the exquisite nature of her microscope photography.

Fresh Science is a national science competition where 16 ‘fresh scientists’ (unpublished in the media) are selected with regard to the quality of their research and their ability to communicate that research.

Photographs and broadcast video footage of the seaweed’s sex life are available.

For photos click here