Algae

Despite being multicellular and photosynthetic, organisms such as kelp and sea moss are macroalgae, not plants, because they lack specialized roots and stems to pump water.

The world's largest species of marine algae is giant kelp, which can grow as much as two feet per day from depths of about 100 feet up to the ocean surface.

Scientists have collected critical minerals from ocean water using seaweed, a type of algae that leaves behind a mineral-rich powder called bio-ore after being processed into biofuels.

Green algae have lived on Earth for about one billion years, roughly twice as long as the first plants.

Molecules derived from algae can be found in foods such as ice cream, salad dressings, brownie mix, and gravies, as well as in products such as toothpaste, multivitamins, and egg substitutes.

Diatomite, a sedimentary rock used as a filtration material in beer, wine, swimming pool water, motor oil, and pharmaceuticals, is formed from the fossilized shells of diatoms, a type of algae.

Harmful algal blooms can occur in warm, nutrient-rich, stagnant waters and are often associated with the rapid reproduction of blue-green algae—a misnomer for cyanobacteria, not algae.

As of 2026, the Great Atlantic Sargassum Belt is the world's largest macroalgal bloom, with seaweed stretching from the Caribbean to West Africa.

Astronauts on the International Space Station have tested an algae-powered bioreactor that converts carbon dioxide, water, and light into oxygen and edible, protein-rich biomass.

Algae can capture carbon dioxide at rates up to 50 times faster than land-based plants and can be grown in tanks that use one-tenth the land footprint of terrestrial plants.