Japan Team Finds Annual Ring Patterns in Marimo

Society Science

Tokyo, Jan. 5 (Jiji Press)--A team of Japanese researchers has found a spherical annual ring structure formed in marimo, a freshwater green alga living in Lake Akan in northern Japan.

According to an article published in British journal Scientific Reports, the team also revealed that algae in the central part of marimo, a Japanese government-designated special natural treasure, decompose, contributing to the growth of marimo at the lake, located in Kushiro in the northernmost prefecture of Hokkaido.

The team, including Kobe University professor Keisuke Nakayama and Yoichi Oyama at the Marimo Research Center of the Kushiro Board of Education, successfully created images of the inside of marimo, or aegagropila linnaei, through magnetic resonance imaging analysis.

They confirmed a spherical annual ring structure some 4-5 centimeters from the marimo surface covered by green alga filaments.

Marimo balls, made of thin algae each some 3 centimeters long, are "polished" by the oscillation and rotation induced by wind waves between summer and autumn, enabling the formation of a highly dense surface of green alga filaments.

[Copyright The Jiji Press, Ltd.]

Jiji Press