Each ocean has its own distinct varieties of seaweed. The green seaweeds are found in the shallowest parts of the sea. The brown and red varieties of seaweed grow at deeper levels. The coloured pigments of the seaweed enable them to use the sunlight. In the temperate zone the most common seaweed is the brown algae.
Along the Atlantic and Pacific coasts grows, the Kelp, another form of seaweed. Seaweeds act as fertilizers and are also a source of iodine. It is also a primary source of food for the ocean life.
Below Seaweed info from Wikipedia (Read More):-
Seaweed is a loose colloquial term encompassing macroscopic, multicellular, benthic marine algae.[1] The term includes some members of the red, brown and green algae. Seaweeds can also be classified by use (as food, medicine, fertilizer, industrial, etc.).
A seaweed may belong to one of several groups of multicellular algae: the red algae, green algae, and brown algae. As these three groups are not thought to have a common multicellular ancestor, the seaweeds are a paraphyletic group. In addition, some tuft-forming bluegreen algae (Cyanobacteria) are sometimes considered as seaweeds — "seaweed" is a colloquial term and lacks a formal definition.
http://en.wikipedia.org/wiki/Seaweed
