Occurrence, Distribution and Historical Perspective

Abstract

The plant life in the sea is extremely rich and some exploitation of these resources has taken place over hundreds of years. At the present time, when man is increasingly turning his attention to the ocean as a major source of food and industrial chemicals the plant life, both attached and floating, is becoming of great importance. Where seaweed has been used, both in the past and at present, it has been as freshly gathered plants, but there are a few industries that can use seaweed cast up on the shore as drift, provided it is soon collected. The great amount of attached seaweed existing in the world is probably not fully realized: if it were, it is possible that greater efforts would have been made in the past to find means of collecting and using all this raw material. The minute floating plants of the sea, the phytoplankton, form the basic foodstuff for small animals and fish, and do not in themselves have a direct commercial use, although recent work (see Chapter 8) indicates that ‘artificial food chains’ in mariculture systems utilizing phytoplankton as the basic trophic level are feasible.