Algae
Yes by algae we mean seaweed. As these water lettuces floating around and grow on corals and rocks. Many cultures worldwide, going back to ancient times, have always known about the benefits of eating algae and adding it to daily menu. Naturally growing seaweeds are an important source of food, especially in Asia. They provide many vitamins including: A, B1, B2, B6, niacin, and C, and are rich in iodine, potassium, iron, magnesium, and calcium.
Commercially cultivated algae are marketed as nutritional supplements. Algae are national foods of many nations: China consumes more than 70 species, Japan, over 20 species, also Ireland, Chile, Wales, Korea and many more.