Creating the air we breathe

Algae have been on Earth for more than 1.6 billion years. Early algae existed when there was hardly any oxygen in the air. Over time, they produced so much oxygen waste that it changed the atmosphere.
They put enough oxygen into the air that animals and people could breathe. Without algae, none of us would be here.
Plants also produce oxygen. But algae were producing oxygen more than a billion years before plants even existed.
The algae in the ocean are responsible for more than half of all the oxygen we breathe today. Some experts believe they may have produced as much as 85 percent of the oxygen in our atmosphere.

Trapping carbon dioxide

Algae also help our atmosphere by trapping carbon dioxide and taking it out of the air. Carbon dioxide is poisonous to people and animals. It also traps the heat in our atmosphere, warming the planet.
Plants also take carbon dioxide from the atmosphere. When plants are burned or they decay, they release the carbon dioxide they had pulled in. In some cases, it may take 100 years for the carbon dioxide to return to the atmosphere.
But after algae die, their trapped carbon dioxide sinks to the bottom of the ocean. It could be 1 million years before it returns to our atmosphere. This helps slow global warming.

Dining on algae

Algae are a super-important food source. Sea animals, from tiny one-celled zooplankton to giant whales, all depend on algae for most of their food.
Humans eat algae too. Seaweed, a type of algae, is an important part of Asian food. It is in everything from bread to sushi.
You may be eating algae without realizing it. Kelp and other types of algae are used as thickeners in foods such as cheese, pudding, chocolate milk, orange juice and soup. Algae keep ice cream smooth and help get rid of ice crystals. They can also be found in products such as toothpaste and pet food.
Check the ingredient list on some of the foods in your house. If you see “agar,” “alginate” or “carrageenan,” it means there are algae in the product.