The strange "lake balls" of Iceland are now disappearing fast. The green and perfectly round plants, called lake balls, is a form of freshwater alga (Aegagropila linnaei) and is extraordinarily rare.

According to National Geographic, there are only two locations in the world that healthy alga could be found: Lake Akan in Japan (known as Marimo) and Lake Mývatn in Iceland. Cabbage-sized diatoms are abundant in Mývatn because the lake has right environmental factors that will lead to the growth of these unusual plants. Most important of all these factors is its clear water -- a sign of good health.

However, these supersized globes from Iceland are now dwindling in numbers. This is alarming news for Iceland, as the country considers these precious plants as its "national treasures."

Arni Einarsson, director of the Mývatn Research Station, said that the lake balls were gone all of a sudden. The said research station has ever since monitors the balls for almost four decades. The last healthy lake balls were seen last 2013. What could be the reason behind its disappearance?

The water that has become muddy for years caused by surface blooms may be a prime suspect. One diver was hired to check if the colonies are still in good condition, only to return with sad news. "He could only find some dead or decayed. They were not healthy at all." Einarsson said.

Why are there surface blooms in Lake Mývatn? Blame it on pollution. The pollution caused by sewage systems and fertilizers are both fed with nitrogen and phosphorous. As the number of tourists who visited the lake quintupled, there is more demand for proper sewage from hotels. Unfortunately, some septic tanks are already outdated and they cannot simply keep up.

Also, as warming of the lakes continues, algae blooms. According to a study in the AGU Journal, effects of widespread surface warming are diverse. The study determined that there will be a 20 percent increase in algal blooms and 5 percent increase toxic blooms over the next century as water temperature continues to warm.

Even though diatoms aren't as so important in the wildlife in general, their disappearance means that the lake's health is bad already. Lake Mývatn is known as a "duck factory, as waterfowls thrive in the area. If the lake's health will not improve, the ecosystem that relies on the lake will perish.