Freshwater algae can dance around each other in stable groups, held together only by fluid flows in the surrounding water.
of the University of Cambridge and colleagues studied a well-known alga called . 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 鈥� as well as causing them to spin like tops.
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When the colonies swim near the surface of the water, they can get together in one of two formations.
The first is called the 鈥渨altz鈥�: the two colonies orbit around each other, like a planet circling the sun. The second is the 鈥渕inuet鈥�, in which the colonies oscillate back and forth, as if held together by an elastic band.
Goldstein鈥檚 team have developed a mathematical analysis that explains the two dances 鈥� they are caused by the unusual behaviour of the water near its surface.
Journal reference: , ()
