Lake ball (Aegagropila linnaei), also known as Marimo in Japanese, is a rare species of filamentous green algae found in a few lakes in the northern hemisphere. Colonies of such balls are known only in three lakes, Myvatn in Iceland, Lake Akan in Japan and to a much lesser extent in Lake Öisu in Estonia.
The lake ball is a protected species and considered a rare natural phenomenon. Lake ball has been protected as a nature reserve in Iceland since 2006. Therefore Iceland Post issued a single postage stamp feature this rare species as a remarkable fact in the world On September 18, 2009. The stamp shown three lake balls, the one of them was depicted the Iceland’s map.
