A type of freshwater algae known for forming perfectly round aggregates like balls, Kobe University and Kushiro City, etc. say that the national special natural monument "Marimo of Lake Akan" has a tree-ring-like structure. research group revealed.
This was revealed in a joint study conducted by Professor Keisuke Nakayama of Kobe University and Kushiro Marimo Laboratory.
When the group examined the internal structure of marimo in Lake Akan using a technique called MRI, which uses magnetic force to examine the interior of objects, they confirmed that there were structures similar to tree rings found in tree stumps.
When we analyzed five marimo balls of different sizes, we found that tree-ring-like structures were regularly arranged at intervals of 4.5 mm to 6.3 mm.
Converting this to a diameter, it will grow from 9 mm to 12.6 mm in one year, so it will take 20 to 30 years to reach a diameter of 30 cm.
From spring to autumn, marimo roll in the water due to the waves and wind, and their surface is polished, increasing their density.
It is thought that such a difference in surface density creates a structure similar to tree rings, and the research group wants to further elucidate the ecology of the endangered marimo in order to conserve it.
Yoichi Oyama, Deputy Director of the Kushiro City Board of Education's Marimo Laboratory, said, "We've finally come to understand the mechanism behind how much Marimo in Lake Akan grows in a year. This is extremely important for conservation." was talking