Estimation of primary productivity- Winter School on Towards Ecosystem Based Management of Marine Fisheries – Building Mass Balance Trophic and Simulation Models

摘要

The primary production can be defined as the amount of organic materials, whichudby the activity of organisms in unit time is synthesized in a unit volume of water by theudphytoplankton using the solar energy and extending from the sea surface to the bottom ofudthe euphotic zone. The micro algae remove dissolved carbon dioxide and micro nutrientsudfrom the water and using solar energy convert them into complex organic compounds ofudhigh potential energy with the help of photosynthetic pigments, the chlorophylls. Theudprimary productivity will be confined practically entirely to that brought about byudphytoplankton. The growth and distribution is controlled by many factors which may beudphysical factors like light, temperature, currents etc., chemical factors like salinity,uddissolved oxygen content, pH, nutrients such as nitrite, nitrate, phosphate and silicate andudtrace elements, organic minerals etc., biological factors like grazing and reproduction,udhydrological events like upwelling, sinking, turbulence etc., and seasonal variations likeudwinter, summer, spring and autumn.