Seaweeds are marine algae, saltwater dwelling, simple organisms that fall into the rather outdated general category of "plants". Seaweeds are marine algae, saltwater dwelling, simple organisms that fall into the rather outdated general category of "plants". In addition to minerals, such as, iodine and iron, seaweed contains trace elements, which can make a difference in Human health. These trace elements include zinc, boron, chromium, selenium and tin to name a few. Moreover, Seaweed contains a high level of vitamins and particularly vitamin B12, a vital nutritional element, usually found only in meat. Therefore it is recommended as a substitute for meat products in vegetarian diets. source Foodfacts.com Seafood is any sea animal or seaweed that is served as food, or is suitable for eating by humans, such as fish and shellfish (including mollusks and crustaceans). Edible seaweeds are also seafood, and are widely eaten around the world. See the category of sea vegetables. The harvesting of seafood is known as fishing and the cultivation of seafood is known as aquaculture, mariculture, or in the case of fish, fish farming. Seafood is an important source of protein in many diets around the world, especially in coastal areas.