Nanometer-size oxygen bubbles that stimulate aquatic microorganisms have the potential, if mass quantities are used, to purify entire lakes, a team that conducted research last month at Onuma Park in Nanae, Hokkaido, found.

Weighing almost the same as water particles, the so-called nanobubbles remain in the water for a long period, their oxygen stimulating bacteria into vigorously breaking down organic matter, the researchers said.

In the Oct. 20 experiment, 2 tons of water containing oxygen bubbles about 100 nanometers in diameter, made by mixing water and oxygen using a special machine, were poured into a part of a lake suffering from blue-green algae bloom. The bacteria increased about fourfold and the activity of nitrifying bacteria, which decomposes ammonia, intensified some 1.5 times.