On the surface of the earth, the biosphere is a very thin but unique layer. About a century ago, Austrian geologist Seuss introduced its concept into natural science. He published a book on the origin of the Alps in 1875. In the final conclusion, he first put forward the term "biosphere", but it was not accepted by the scientific community. Until Viernaski(вивернадскиий), an academician of the Soviet Academy of Sciences, first studied in the Soviet scientific community 1926, and then in/kloc-0. From 65438 to 0970, Scientific American published in the United States systematically summarized the main progress of biosphere research, especially Hutchinson's paper, and comprehensively discussed the basic characteristics of biosphere. This thin layer in the biological system is more unique than the space outside this thin layer on the earth. If this unique natural environment does not exist, the result will be just like life has not been officially discovered on other planets, and the earth itself can only be a dead world. So, what are the unique manifestations of the space where organisms are concentrated? To sum up, the following basic conditions should be met: (1) must be accompanied by a large amount of liquid water, and there should be three states of solid, liquid and gas at the same time or alternately in this place where liquid water exists, and energy and matter can be actively converted between them. (2) There must be a stable and effective external energy sun to meet the energy required by the biological life process, and also to provide basic power for the change and evolution of the biological environment. (3) In the biosphere, there must be a large enough three-phase material interface, that is, a huge interface active zone with solid lithosphere, liquid hydrosphere and gas atmosphere. For example, like most green plants, its roots extend into solid soil, its stems and leaves completely extend into the atmosphere, and liquid water connects the transformation and circulation of matter and energy through plants. Without the existence of this three-phase interface, it is impossible to develop into higher plants. Because advanced life forms, especially primary productivity, rarely exist only in a single material stage. (4) There must be an atmosphere with constant air pressure and consistent composition. On the one hand, it provides carbon dioxide source for the formation of initial vitality and oxygen source for the breathing of living things, on the other hand, it can protect living things from deadly ultraviolet radiation, and it is an energy storage device that forms a greenhouse effect and prevents excessive energy loss. (5) In this biosphere, there must be a global circulation of energy and matter to help balance the distribution of energy and matter, and create a special environmental structure, which performs a special function beneficial to life activities. In fact, the biological cycle itself is closely intertwined with the geological cycle, atmospheric cycle and water cycle in the inorganic world, and this intertwined space can only be located in a narrow range near the surface interface. Therefore, in the biosphere, it is the only place that allows these four cycles to coexist at the same time and produce complex coupling effects. (6) In the biosphere, the daily and annual changes of environmental factors should not be too great. They are required to have a more subtle combination to meet the requirements of biological growth and development. Therefore, over-cooling, over-heating, over-wetting, over-drying, excessive lack and over-enrichment of nutrient elements, extreme salinity, too small specific surface area and so on. However, it is impossible to expect rich biomass and normal biological activities, especially the normal activities of higher plants, if they deviate too much from the normal combination relationship between various natural environmental factors. Based on the above six basic conditions, the space occupied by a large number of concentrated biological activities is unique and narrow. As mentioned above, life appeared on the earth more than 3 billion years ago, which can be regarded as the first qualitative change in the evolution of the surface inorganic environment. As a result, the organic and inorganic parts in the original single inorganic environment were separated, and the exchange of matter and energy took place between them. This primitive biophysical and biochemical process shows that life has firmly laid the foundation for survival in the specific environment of the earth (the initial life seems to be only produced in water). At the same time, with the oxygen release reaction in the biochemical process, the reducing atmosphere of the original surface environment gradually changes and tends to disappear, and the oxidizing atmosphere gradually increases. About 9 ~10 billion years ago, the dominant position of the surface environment has changed from reduction to oxidation. This change will make the organism enter the second qualitative change. Before the second qualitative change, the existence of living things did not form a circle, but lived under the protection of the ocean to avoid the harm of deadly ultraviolet radiation. In this way, from a global perspective, the distribution of organisms is only a discontinuous existence. It is not until the oxygen in the atmosphere reaches a certain concentration (at present, some scholars tend to think that the oxygen in the atmosphere comes from biological release of oxygen) that this free oxygen becomes the main chemical force on the whole earth's surface. Organisms gradually adapt to this new environment of free oxygen, and the catalase system in organisms has also been developed to resist the oxidative damage of oxygen to organisms and form the physiological and biochemical functions of aerobic respiration (so-called carbon? 3 and carbon? The difference of type 4 plants has a lot to do with this). The emergence and development of aerobic organisms and the continuous proliferation of photosynthetic autotrophs have accelerated the escape of oxygen into the atmosphere and further increased the proportion of free oxygen in the atmosphere. When its concentration accounts for about 10% of the whole atmosphere, a significant ozone layer is gradually formed in the upper part of the atmosphere. Ozone (O3) can strongly absorb the ultraviolet rays from the universe, preventing the deadly ultraviolet rays from reaching the earth's surface in large quantities, thus creating basic conditions for aquatic organisms to develop on land. So in the Devonian period about 400 million years ago, creatures finally made a leap from the ocean to the land. Since then, the biological world composed of plants, animals and microorganisms can spread all over the world, forming a continuous cycle. At present, the proportion of oxygen in the atmosphere remains basically unchanged. In a year, 1 hectare of young and prosperous forests will produce 10 tons of oxygen and consume 30 tons of carbon dioxide. Every 2 million years or so, there is 65.438+0.5 billion cubic kilometers of water on the earth, which is cracked by photosynthesis of green plants and reformed by respiration. The oxygen formed after cracking temporarily stays in the atmosphere, which is equivalent to about 2000 years, and is circulated once. The vertical amplitude of the biosphere on earth is about the distance from the deepest ocean (1 1000 meters above sea level) to 9000 meters above sea level. Scientists found fish at 7000 meters below sea level; At a depth of 6000 meters, there are still 4.5 milligrams of plankton per cubic meter of seawater. According to the investigation of aquatic organisms, in the seabed more than 10000 meters deep (such as the deep ditch in the Philippines), every gram of wet mud still contains 654.38+million bacteria, even reaching 1 10,000 bacteria. Spores of bacteria and fungi floating in the atmosphere were also found at a height of 9000 meters above the surface. Under the extremely harsh environmental conditions far away from the surface, only this extremely primitive lower organism can survive, and most of the total biomass (99.9%) can only survive in a thin layer much smaller than the above range. If compared with the earth itself, the vertical amplitude of the biosphere is negligible. Aside from the earth's atmosphere for the time being, only from the radius of the earth, the thickness of the biosphere only accounts for a small share. For example, until 1966, according to 46,500 observations made by 12 ground observation stations around the world on 13 artificial earth satellites, it was calculated that the equatorial radius of the earth was 6378.169 0.008km, which was about 3,200 times the thickness of the biosphere (the average biosphere Table 6548 compares the quality of biomass with other components in the world according to the works of American scholar Elridge 1977. After a little calculation, it is listed in table 10-2. Since the origin of life, the elements distributed on the earth have been changing. With the development of prokaryotes, elemental carbon and elemental oxygen in rocks began to transform into organic matter or atmosphere. As a result, the atmosphere gradually changed from reducing medium to oxygen-containing medium to support the continuation and evolution of life. The composition of abiotic substances (lithosphere, hydrosphere and atmosphere) is different from that in the biosphere, so organic matter has to extract related elements from the selected medium. In this regard, please refer to the figure 10- 1, which shows the composition and concentration of elements existing in the lithosphere, which is the material basis for the existence and development of the whole organic world and also a measure. Therefore, in the geographical environment, if we study the migration and accumulation of chemical elements and biogeochemical processes, we must consider the existence of such elements in the lithosphere. Further analysis shows that because these basic elements are widely scattered on the earth's surface, the biosphere has to absorb, store and reuse some elements strongly to maintain the survival process of biomass and the development of the whole biosphere. Thus, the essence of element circulation in life is discovered. The discovery of biogeochemical process and biological material cycle is one of the major discoveries in the biosphere, which will lead people to reveal the dynamic laws of geography more deeply, and the comprehensive study of various dynamic laws will push the research level of theoretical geography to a new level.