Spherical marimo inhabiting Lake Akan in Kushiro City, Hokkaido = May 2019 (provided by Isamu Wakana)

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Spherical marimo inhabiting Lake Akan in Kushiro City, Hokkaido = May 2019 (provided by Isamu Wakana)

Marimo's growth process

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Marimo’s growth process

By the 13th, the National Institute of Genetics (Mishima City, Shizuoka Prefecture) and others have been able to maintain a spherical shape even though the center of Marimo, a national special natural monument that inhabits Lake Akan in Kushiro City, Hokkaido, is hollow. Summarized the research results that it is due to the action of bacteria.

As a result of examining a total of eight marimo with a diameter of 4 to 22 cm, it was confirmed that a large number of bacterial “cyanobacteria” were present.

Bacteria produce a sticky substance, which is said to be the cause of the gravel of the lake being taken in, increasing the airtightness and strength, and causing the marimo, which is hollowed out as it grows, not to collapse.