The rare Icelandic marimo populating Lake Mývatn have vanished, reports National Geographic. Marimo, otherwise known as Aegagropila linnaei or lake balls, are widespread in the Northern hemisphere though the forms that used to populate Lake Mývatn – perfect spheres 10-15 cm across – are found in just a few other places.
“If somebody would have told me 20 years ago that the lake balls could disappear so suddenly I would not have believed them, it is a very sad story,” biologist Árni Einarsson, the director of the Nature Research Institute at Lake Mývatn, said.
As reported, pollution is believed to be the culprit behind the marimo’s disappearance. Mining operations for diatom shells in the 1960’s caused a release of phosphorus and nitrogen into the already nutritious Lake Mývatn. The added nutrition was prime food for bacteria that burst into dense blooms, limiting much needed light penetration to the marimo on the lake floor.
Although mining operations seized in 2004 the ecosystem has continued to dwindle.
According to Árni, should the nutrient balance be restored in Lake Mývatn, reintroduction of marimo might be attainable. For this to be a possibility further nutrient input to the lake would have to be limited. This would mean decreasing traffic – a result of Iceland’s tourist boom – in the area.
The common name for lake balls in Icelandic is ‘Kúluskítur’. Directly translated it means “round shit” which is supposedly what fisherman used to call the balls when they got caught in their fishing nets.