The vast majority of the world's lakes are small in size and short lived in geological terms. Only 253 of the thousands of lakes on this planet have surface areas larger than 500 square kilometers. At first sight, this statistic would seem to indicate that large lakes are relatively unimportant on a global scale; in fact, however, large lakes contain the bulk of the liquid surface freshwater of the earth. Just Lake Baikal and the Laurentian Great Lakes alone contain more than 38% of the world's total liquid freshwater. Thus, the large lakes of the world accentuate an important feature of the earth's freshwater reserves-its extremely irregular distribution. The energy crisis of the 1970s and 1980s made us aware of the fact that we live on a spaceship with finite, that is, exhaustible resources. On the other hand, the energy crisis led to an overemphasis on all the issues concerning energy supply and all the problems connected with producing new energy. The energy crisis also led us to ignore strong evidence suggesting that water of appropriate quality to be used as a resouce will be used up more quickly than energy will. Although in principle water is a "renewable resource," the world's water reserves are diminishing in two fashions, the effects of which are multiplicative: enhanced consumption and accelerated degradation of quality.

This book was the first to give a detailed description of the lakes of the Warm Belt of the earth. The book is composed of three parts. The first part gives the general geological, meteorological and hydrological features of the tropical and subtropical areas and permits the location of the warm lakes in the world hydrology. The second part presents the main lakes and rivers of South America, Central America, Africa, the Middle East, South-East Asia and Australia with an up-to-date description of their history, hydrology, hydrodynamics, chemistry and biology. The third part is an attempt to analyse the mechanisms of water circulation in warm lakes and to determine the dominant and common features which explain the chemistry of warm lakes and the composition of their biota, such as phytoplankton, bacteria, zooplankton and fish. The last chapter of the book synthesises all these elements by presenting the typical food webs of tropical lakes. This volume will be invaluable to students of ecology, liminology and hydrobiology, particularly those doing post-graduate and research work.