Lake Ball of Iceland

 

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. 

The species has three different growth forms, lake ball being one of them reaching up to 10-20 cm in diameter. One is epilithic (growing on rocks) and is usually found on the shaded side of the rocks. Another growth form lives as free-floating filaments, as small tufts of unattached filaments that frequently form a carpet on the muddy lake bottom. The third growth form is the lake ball proper, where the algae grow into sizable balls of densely packed algal filaments that radiate from the center. The balls do not have a kernel of any sort.

Each year around 500.000 tourists visit Lake Akan and a special Lake Ball Festival is held each year in autumn. It is a remarkable fact that two such rare and similar communities of algae should be found so far away from each other. The lakes in Iceland and Japan still have something in common. They are situated in highly volcanic areas with geothermal heat in the banks of both lakes. Both Lake Mývatn and Lake Akan are protected, the former as a nature reserve, the latter as a national park.