Algae blooms can take over rivers, estuaries, lakes and coastal areas. Imagine going to a beach that looks like it has stepped out of a Dr. Seuss book: a sea of green, mushy, smelly carpet lies where the ocean should be as far as the eye can see. This mental picture can give you a visual of what happened in China’s Yellow Sea. Vacation-goers to popular Chinese resort town Quindao were faced with murky, slimy green waters instead of the usually beautiful beaches around the Yellow Sea.

What is an algae bloom?

The phenomenon known as an “algae bloom” or sometimes “red tide” is a sudden explosion or bloom of algal growth within a body of water. Red, brown or green algae can cause algal blooms. Cyanobacteria, also known as blue-green algae, can also burst into an algal bloom.

What causes an algae bloom?

Algae blooms are caused by high temperatures, agricultural fertilizer runoff or a combination of the two. When farmers fertilize their crops, this fertilization can runoff into the water column. This fertilization fuels incredible growth of algae. The algae can grow so much that it changes the ecosystem of the water column.

How do algae blooms affect our planet?

When an abundance of algae grows within a body of water, it kills off the other plants living there. This creates a cesspool of plant detritus that bacteria then feed on. With so much available food, the bacteria quickly multiply. These bacteria also feed on the oxygen in the water column. As these bacteria feed on the oxygen, they sap it up so that none is left for other creatures within the water. Soon, all the fish and natural plants within the body of water die.

Some of these species of algae also produce neurotoxins that kill fish. Fish that are able to consume them are then poisonous to the predators that feed on them, killing them off. One of these predators is us: shellfish that eat the algae are toxic to humans. Fisherman in affected areas suddenly find themselves unable to support themselves as dead fish and plants liter the area. Even the living fish might be toxic and cannot be fished for.

Since fertilization runoff causes many of the algae blooms, farmers in affected areas are making a concerted effort to halt the runoff. An important factor in this process is installing effective irrigation systems that don’t feed water into nearby lakes, rivers and streams. Scientists are currently searching for a solution to this large problem within water ecosystems.