10.1016/s0967-0653(98)82170-4

Abstract

Turbulence consists of irregular movements of the molecules in a fluid, through which mechanical energy is transmitted and decayed.Through this mechanism, transport of heat and of materials in solution is accelerated along the respective gradients.This appears simply enough, although a rigorous approximation to the physics of turbulence may appear rather discouraging.To the biologist, the energy involved in turbulence is obviously material and responsible for the maintenance of ecosystems.This may seem less than obvious when ecologists often have been guilty of neglecting essential energy inputs by fixation on photosynthesis and to transfers of energy delivered from it to other trophic levels.Other energy sources active on earth that contribute as well to the organization and maintenance of ecosystems have been neglected systematically, as is obvious in the case of vascular terrestrial vegetation, where energy of transpiration mediates the input and translocation of water and nutrients and quantitatively widely exceeds the energy of photosynthesis.Furthermore human civilization, besides food, uses increasing amounts of energy from many sources.Turbulent energy in aquatic environments may be relatively compared, at least, with transpiration energy in terrestrial ecosystems.Primary producers in open waters are very small, and never build the relatively persistent structural frame of terrestrial vegetation.Phytoplankton assimilates in a top layer, usually 40-80 m thick, and the formed organic matter enters a food chain that extends to maximal depths.Turbulent energy, mostly originated by the interaction between atmosphere and water at the surface, plays an essential role in returning the nutrients from the levels and places where they tend to accumulate, chiefly in deep