The Mysterious Green Orbs That Float by Day and Sink at Night
Known in Japan as marimo, the unusual balls of algae seem to follow a biological clock that helps them pursue sunlight while underwater.
Moss balls, lake balls, Cladophora balls, marimo: Whatever you call them, they’re strange — and they’re beautiful.
These mysterious green orbs occupy cool lakes in the Northern Hemisphere in places like Scotland, Iceland and Ukraine. In Japan, they are a protected species and official national treasure.
Under certain conditions, marimo form when a type of algae bind together and
roll in the currents in the bottom of shallow lakes,
collecting in large colonies. Sometimes the orbs — which can grow to nearly a foot in diameter — rise to the surface during the day, and then sink back down at night.
Marimo contain many mysteries. But now, at least one has been solved. In
a paper published this week in Current Biology, biologists at the University of Bristol in England described how this fuzzy freshwater friend floats and sinks. The algae regulate photosynthesis with a biological clock, and in the process, release oxygen bubbles that carry them toward the sun. ...
