Marimo moss balls: Do they really have anything to do with moss? 

All of you have read about algae in your Biology or Life Science cases, right? They are a large and diverse group of photosynthetic organisms that are both unicellular and multicellular in characteristic and are mostly found under water. While majority of algae can’t be seen with naked human eyes, some are large enough to be visible. These look like nothing but those small, green-coloured, seedless plants growing randomly on the ground or around the surfaces of trees and rocks.  

One of the most famous and noticeable multicellular algae is called Marimo moss balls. In case you are wondering whether or not Marimo moss balls have something to do with moss, the answer is no. Turns out that it is nothing more than a misnomer.  

Marimo moss balls: Algae, not moss 
Also known as lake balls, Marimo moss balls are not moss at all. They are a type of algae. They grow into long, hair-like green filaments and are found mostly at the bottom of world’s freshwater lakes especially in places like Iceland, Siberia, Australia, Ukraine, Ireland and Japan among others. They often stay tangled together and grow to resemble a velvety sphere. This is what lends them the appearance of moss. Marimo moss balls are usually one foot in diameter.  

Marimo moss balls were first discovered in the 1820s by Austrian botanist Anton E. Sauter in Lake Zell of Austria. However, it was named Marimo by Japanese botanist Takiya Kawakami in 1898. It was a combination of two Japanese words mari meaning bouncy play ball and mo meaning aquatic plants.  

Marimo moss balls: Floats during the day and sinks at night 
Those who have seen Marimo moss balls close up know that they have a unique characteristic. Wondering what is it? Well, they tend to stay afloat during the daytime, but as soon as night falls, they sink. Can you guess why this happens? Well, the first is because of photosynthesis, it’s easier of them to produce their food in presence of the sunlight if they are right at the surface. However, at night, they sink in. This is connected to something called circadian rhythms. These refer to the internal body clock that regulates the 24-hour cycle of biological processes in animals and plants. In this case, Marimo moss balls simply rise and go down as per their own internal body clock. Isn’t that cool?  

Marimo Matsuri: A Japanese festival dedicated to Marimo moss balls 
In Japan, a native tribe called Ainu have their own unique way of saving the Marimo moss balls. Do you know what they do? They hold a three-day festival each year near Lake Akan (existing home of Marimo moss balls) called Marimo Matsuri during the month of October. The goal is to appreciate Mother Nature as a whole and especially help conserve Marimo moss balls. As part of the festival, people get to learn all about these lake balls and even engage in special rituals combined with folk music and dance to honour them.  

Decline of Marimo moss balls 
Unfortunately, over the years, Marimo moss balls have been disappearing. In fact, in the last three decades their count has reduced by 50 per cent. Currently, they can only be traced in two of their favourite habitats: Lake Myvatn in Iceland and Lake Akan in Japan.  

Experts cite that the factors responsible for this sharp decline include pollution, overuse of pesticides, and above all climate change. In fact, these algae are now part of the endangered species list. 

However, another major reason behind their drastic fall is illegal aquarium trade. Turns out, many people like keeping Marimo moss balls as pets or souvenirs, thus forcing companies to harvest them from freshwater lakes. In fact, this had aggravated so much, that the Japanese government in 1977 had requested people to return the lake balls in their possession, to save them from extinction.