Phytomass and Primary Production of the Various Vegetational Zones and of the Entire Biosphere The biosphere is that thin layer at the earth's surface in which living organisms exist and biological cycling takes place. It includes the upper horizons of the soil in which plants root, the atmosphere near the ground, (insofar as organisms penetrate this space), and all the surface waters. More than 99% of the earth's biomass is phytomass, to which we shall limit our discussion. Amounts of phytomass are distinctly related to vegeta tional zones. Because accurate determination of phytomass and primary production is difficult, only gross estimates have been available until recently. However, in 1970, Bazilevich et al. published (in Russian) more accurate calculations, based on the rapidly accumulating literature, for the various thermal zones and bioclimatic regions of the earth. These authors calculated mean phyto mass and mean annual primary production for the various regions as dry mass (in tons) per hectare. On the basis of measurements of the areas covered by the individual regions, excluding rivers, lakes, glaciers, and permanent snow, total phytomass and total annual primary production for the various regions were obtained (see table). The sum of these figures is the phytomass and annual production of the land surface of the earth. In addition, the table gives corresponding data for the waters of the earth. The values involved are potential i. e. , they are based on natural vegetation uninfluenced by man.

We shall limit our observations to the conditions in natural ecosystems, since it would be beyond the scope of this book to embark upon a consideration of secondary, man-made ecosystems. 2. Classification of the Geo-biosphere into Zonobiomes The biosphere is the thin layer of the earth's surface to which the phenomena connected with living matter are confined. On land, this comprises the lowest layer of the atmosphere permanently inhabited by living organisms and into which plants extend, as well as the root-containing portion of the lithosphere, which we term the soil. Living organisms are also found in all bodies of water, to the very depths of the oceans. In a watery medium, however, cycling of material is achieved by means other than those on land, and the organisms (plankton) are so different that aquatic ecosystems have to be dealt with separately. The biosphere is therefore subdivided into (a) the geo-biosphere comprising terrestrial ecosystems, and (b) the hydro-biosphere, comprising aquatic ecosystems, which is the field of hydrobiologists (oceanographers and limnologists) . Our studies are confined to the geo-biosphere (Walter 1976), which constitutes the habitat of man and is, therefore, of special interest. The prevailing climate, being the primary independent factor in the environment, can be used as a basis for further subdivision of the geo-biosphere since the formation of soil and type of vegetation are dependent upon it (see p. 3), and it has not yet been substantially influenced by man.

Zonobiome, desert, Tundra, Taiga, laurel, ecosystem, grassland, climate, forest, tropical, woodlands, rain.

Vegetation, soil and climate are the most important components of ecological systems. This long-awaited fourth edition of the well-established textbook by Heinrich Walter summarizes our knowledge of the earth's ecology and constitutes the basis for a deeper understanding of the larger interrelations on a global scale. While Walter's general concept remains unchanged, the individual chapters have been completely revised, enlarged and updated. The author's intimate knowledge of practically all classes of plants and climatic zones allows him to describe the various ecological systems in close detail. This richly illustrated textbook is a must for every student in the plant sciences.

By the end of the last century, the only region in all of Europe where the natural vegetation remained untouched over large expanses was Eastern Europe. Information on the vegetation of this region however, remained mostly unavailable to western scientists although the ecological approach to botanical research originated in Eastern Europe. Heinrich Walter was born in Russia, studied Natural Sciences - with emphasis on botany - in Odessa and is familiar with all relevant Russian literature on ecology. This volume thus offers scientists worldwide a unique and comprehensive survey of all relevant research, including the mostly unknown literature published in Russian.

Twenty-nine, prominent, international researchers provide contributions which deal with understanding the basic ecophysiological and molecular principles governing the functioning of plant systems in relation to their environment. Divided into two headings: biotic and abiotic; the first consists of abiotic, natural environmental factors--light, ultraviolet radiation, chilling and freezing, high temperatures, drought, flooding, salt and trace metals. The latter half presents anthropogenic aspects including allelochemicals, herbicides, polyamines, air pollutants, carbon dioxide, radioisotopes and fire.

With one volume each year, this series keeps scientists and advanced students informed of the latest developments and results in all areas of the plant sciences. This latest volume includes reviews on plant physiology, biochemistry, genetics and genomics, forests, and ecosystems.