Food and Food Webs

Abstract

In each water mass a different amount of organic matter and inorganic salts is dissolved; some waters will be well fertilized with plant foods, others more poorly or even barren. There exist desert areas in the oceans as well as on the land. The Sargasso Sea is supposed to be one such desert, and there are others east of Sydney in the Tasman Sea, and west of Western Australia in the Indian Ocean. As the plants and animals grow and multiply, the nutrient values of the water change and so a water originally rich may become poor and infertile. This is the cause of those deserts which are close to fertile areas such as the Gulf Stream, the Coral Sea and the Banda Sea respectively. Large phytoplankton blooms are often associated with land masses in the warmer waters where heavy rainfall assures a steady supply of nutrients derived from the land. Usually, the diatoms are far more abundant in such rich areas as the Banda, Timor, Arafura Seas, the water above the Carioca Trench off Venezuela and the northern Coral Sea; while dinoflagellates take over in waters poorer in inorganic nutrients. An exception is the eastern Gulf of Mexico, off the west coast of Florida, where dinoflagellate red tides are common.