‘Dancing’ algae discovered

From New Scientist:

‘Dancing’ algae can waltz and minuet

* 17:35 20 April 2009 by Michael Marshall and Sandrine Ceurstemont

Freshwater algae can dance around each other in stable groups, held together only by fluid flows in the surrounding water.

Raymond Goldstein of the University of Cambridge and colleagues studied a well-known alga called Volvox. This species lives in colonies of cells around a thousand strong: the individual cells live on the surfaces of spheres of jelly.

Each cell has a pair of flagella: thin flexible rods that extend out into the surrounding water and function as outboard motors, propelling the colonies around – as well as causing them to spin like tops.

When the colonies swim near the surface of the water, they can get together in one of two formations.

The first is called the “waltz”: the two colonies orbit around each other, like a planet circling the sun. The second is the “minuet”, in which the colonies oscillate back and forth, as if held together by an elastic band.

Goldstein’s team have developed a mathematical analysis that explains the two dances – they are caused by the unusual behaviour of the water near its surface.

Journal reference: Physical Review Letters, in press (pdf)

These videos are about human waltzing and minuet.

Coralline Algae In The Mediterranean Lost Their Tropical Element Between 5 And 7 Million Years Ago: here.

Vampire Algae Suck on Salad: here.

Vanishing Marine Algae Can Be Monitored From a Boat With Your Smartphone: here.

Spring Rain, Then Foul Algae in Ailing Lake Erie: here.

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