The History and Science of Marimo

Their Ancestors Lived in the Sea?

For marimo to grow to the size of a baseball, it was often said, would take between 150 to 200 years. Recently, however, it was revealed that the marimo's growth rate is not unduly slow but rather recent water conditions are not conducive to their growth. More than lake water, diluted sea water or salt water encourages marimo's growth. There are more than 20 lakes in Japan and neighboring countries where marimo have been confirmed to live. The greater part of...

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The Marimo’s Survival Techniques in Nature

Marimo are photosynthetic plants but can subsist in murky water with the scantest amount of sunlight. This capacity enables the epilithic filament form of marimo, unlike many other water plants, to thrive while attached to dead trees or rocks in water depths of over 10 meters. Aggregate and spherical marimo do not attach themselves to rocks or submerged trees but are instead moved about by the lake's undercurrents. Though these forms of marimo are not stationary plants, aggregate and spherical marimo...

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The Natural and Forced Deaths of Marimo

Above: A marimo flattened by the winter ice which covers Lake Akan. The number of marimo in Lake Akan and other lakes has been slowly decreasing. A large portion of the blame for the decreasing number of marimo is attributed to pollution and its effect on the water and environment where marimo live. Pollution however has a surprising accomplice which may outwardly appear guiltless but exacts a destructive toll on marimo nonetheless. From the end of December until sometime within the first...

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Why Do Marimo Become Spherical?

Marimo live at the bottom of Lake Akan, a mysterious lake nestled between the slopes of Mt. O-Akan and Mt. Me-Akan. Within this large lake there are only two locations, Churui Bay and Kinetanpe Bay both situated in the northern area of the lake, where profusions of velvet like spherical marimo can still be seen. In the Taisho Era (1912-1925), marimo could also be seen at Shurikomabetsu Bay and Osaki in the western section of Lake Akan however use of...

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A Walk Along the Shores of Lake Akan, and a Journey to the Past

Today has been a full day of good rest for me. I slept late this morning trying to sleep off some of my fatigue. In the morning I strode down to the Akan Visitor's Center to see what I could discover about the "wonder of Lake Ball 'Marimo,'" algae ball. In Ainu Marimo is "To karibu" meaning "ball of the marsh" or "Torasante" meaning "seed of the lake." Marimo is the name given to a type of land locked algae formed...

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The Biological Properties of Marimo Balls

With the recent surge in enthusiasm among collectors and hobbyists for marimo moss balls, a number of our curious readers have asked whether the moss balls are fit for human consumption. Before we can answer this question, it will be good to cover some of the basics of marimo moss ball biology, history, care and propagation. After all, these beautiful works of natural art are best protected and enjoyed. Basic Biology of Marimo Moss Balls:  While often sold in aquaria as “marimo...

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A History of the Marimo’s Plight

In the mid-1920's marimo in Lake Akan were greatly affected by both thievery and decreases in the lake's water level. Both marimo and their environment were under attack. To circumvent the marimo's looming threat of extinction in Lake Akan, the Marimo Festival was inaugurated. This path of devastation, fortunately interrupted and ransomed by the Marimo Festival, is documented in the following pages. Designation of marimo in 1921 as a Natural Treasure also marked, at least for the marimo of Lake Akan,...

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The Maximum Size of Marimo in Nature

The above map represents Lake Akan. The solid line along the lake shore represents the areas of the lake where marimo live. Spherical marimo are distributed and live only in the areas marked in green. Marimo are a perennial plant. If they do not remain in areas that receive some degree of sunlight throughout the year, they cannot survive. The epilithic filament form of marimo live attached to crags at the lake's bottom in comparatively deep waters, approximately 10 meters deep,...

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A History of Marimo Taxonomy

Your marimo will grow in room temperature tap water, changed every one to two weeks, depending on the season— more frequently in the summer less in winter. In especially hot weather, you can cool your marimo in the refrigerator, above 25°C. Indirect sunlight is best for growing marimo, as they’re adapted for low light conditions. They can be immersed in club soda water to increase photosynthesis, but it also occurs naturally in normal household lighting. Note: Increased carbon dioxide is beneficial...

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The Various Growth Forms and Artificial Cultivation of Marimo

Marimo moss balls are a unique species of algae that form into spherical shapes. They grow most commonly in the lakes of Japan - where they are revered and considered a national treasure - as well as in Scotland, Estonia and Iceland.  In 1898, a Japanese botanist termed the algae marimo. The first part of the word, mari, means bouncing ball. The second part, mo, is used to describe plants that grow in water. Species Types: There are three types of marimo,...

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