Matter accumulation and energy expenditure in planktonic ecosystems at different trophic levels

Functional peculiarities of pelagic communities from temperate and tropical zones of the ocean have been investigated in terms of food-web interrelations and balance sheets of matter and energy of the major populations and ecological groupings. Ranging from temperate or epiplankton ecosystems to tropical oceanic or deepwater ones, as well as from upwelling zones to stable oceanic oligotrophic regions, the following regular changes in the communities' main functional indices have been established: (1) enlargement of the food spectrum, omnivorousness and predatory activity; (2) reduction of rations and rates of organic matter accumulation in the lower heterotrophic levels with simultaneous increase of energy expenditure; (3) increased trophic complexity and stability of communities. Epiplanktonic systems of low stability proved to be richer and commercially more profitable.