All living beings of planet Earth come into close contact with each other and with the environment, thereby forming ecosystems. These communities of interacting organisms are not isolated from each other. They are interconnected by various relationships, primarily food. The totality of ecosystems forms a single planetary ecosystem, which is called the biosphere. This article will consider the structure of the biosphere, its composition and main functions.
Science
This concept was first introduced into science by J. B. Lamarck back in 1803 and meant the totality of all living organisms on the planet Earth. At the end of the nineteenth century, the term "biosphere" was used by J. Zuse, who included the inanimate matter of sedimentary rocks in the structure of the biosphere. The doctrine of the biosphere appeared in 1926, when V. I. Vernadsky summarized a huge amount of scientific information, one way or anotherillustrating the relationship between living and non-living matter. The scientist was able to show that our planet is not only inhabited by living organisms, but is also being actively transformed by them. In addition, according to Vernadsky, human intervention in natural processes is so significant that it is possible to speak of the noosphere - a new phase in the development of the biosphere. Today, the science of the biosphere combines data from different fields of knowledge. Among them are biology, chemistry, geology, climatology, oceanology, soil science and others.
The structure of the biosphere is such that living organisms can independently maintain the necessary composition of the soil, atmosphere and hydrosphere. They play a key environmental role. Based on this, scientists put forward a hypothesis that the soil and air were created by living organisms themselves over hundreds of millions of years of evolution. Having studied the similarities in the structure of geological rocks that lie deeper than the Cambrian, with later rocks, Vernadsky suggested that life on the planet existed in the form of the simplest organisms almost from the beginning. Later, geologists proved the fallacy of this hypothesis.
Since the sun is the energy basis for the existence of all life on Earth, the biosphere can be considered as a shell, the structure and composition of which are formed due to the joint activity of living organisms and are determined by the influx of solar energy. Now let's get acquainted with the structure of the Earth's biosphere.
Living and non-living
Considering the composition and structure of the biosphere, first of allit is worth noting that it consists of living and non-living matter (inert matter). The bulk of living organisms is concentrated in three geological shells of the Earth: the atmosphere (air layer), hydrosphere (oceans, seas, and so on) and lithosphere (top layer of rock). However, these shells are unevenly distributed in the largest ecosystem. Thus, the hydrosphere is fully represented in the structure of the biosphere, while the lithosphere and atmosphere are partially represented (upper and lower layers, respectively).
The non-living component of the biosphere consists of:
- Biogenic substance, which is a product of vital activity of living organisms. It includes: coal, oil, peat, natural limestone, gas, etc.
- Bioinert substance, which is a joint result of the vital activity of organisms and non-biological processes. This includes: soil, silt, water reservoirs and so on.
- Inert substance, which is included in the biological cycle, but is not a product of the vital activity of living organisms. This group includes: water, metal s alts, atmospheric nitrogen, etc.
Boundaries of the biosphere
Such concepts as the composition, structure and boundaries of the biosphere are closely related to each other. Despite the fact that bacteria and spores have been found at altitudes up to 85 kilometers, it is believed that the upper limit of the biosphere is 20-25 km. At high altitudes, the concentration of living matter is negligible due to the strong influence of solar radiation.
In the hydrosphere, life is present everywhere. And even in the Mariana Trench, whose depth is 11 km, the scientistfrom France, J. Picard observed not only invertebrates, but also fish. Bacteria, algae, foraminifera and crustaceans live under more than 400 meters of Antarctic ice. Bacteria are found under a kilometer layer of silt and in groundwater. Nevertheless, the greatest concentration of living beings is observed at a depth of up to 3 km. Thus, the boundaries and structure of the biosphere in different parts of the planet may be different.
Atmosphere, lithosphere and hydrosphere
The atmosphere is mainly composed of oxygen and nitrogen. It contains small amounts of argon, carbon dioxide and ozone. The life of both land and water creatures depends on the state of the atmosphere. Oxygen is necessary for the respiration of living organisms and the mineralization of dying organic substances. Well, carbon dioxide is used by plants for photosynthesis.
The lithosphere has a thickness of 50 to 200 km, however, the main number of species of living organisms is concentrated in its upper layer several tens of centimeters thick. The spread of life deep into the lithosphere is limited due to a number of factors, the main of which are: lack of light, high density of the medium and high temperature. Thus, the lower boundary of the distribution of life in the lithosphere is a depth of 3 km, at which some types of bacteria were found. In fairness, it should be noted that they did not live in the ground, but in groundwater and oil horizons. The value of the lithosphere lies in the fact that it gives life to plants, nourishing them with all the necessary substances.
Hydrosphereis an essential component of the biosphere. About 90% of the water supply falls on the World Ocean, which occupies 70% of the planet's surface. It contains 1.3 billion km3, and rivers and lakes contain 0.2 million km3 of water. The most important factor in the vital activity of the organism is the content of oxygen and carbon dioxide in water.
Fascinating numbers
The composition, structure, and functions of the biosphere surprise with their scale. We will now get to know some interesting facts. Water contains 660 times more carbon dioxide than air. On land, the diversity of the plant world prevails, and in the sea - the animal world. 92 percent of all biomass on land is green plants. In the ocean, 94% are microorganisms and animals.
On average, once every eight years, the Earth's biomass is renewed. Land plants need 14 years for this, ocean plants - 33 days. It will take 3000 years for all the water of the globe to pass through living organisms, oxygen - up to 5000 years, and carbon dioxide - 6 years. For nitrogen, carbon and phosphorus, these cycles are even longer. The biological cycle is not closed - about 10% of living matter passes into sedimentary deposits and burials.
The biosphere accounts for only 0.05% of the mass of our planet. It occupies about 0.4% of the volume of the Earth. The mass of living beings is only 0.01-0.02% of the mass of inert matter, however, they play a very significant role in geochemical processes.
200 billion tons of organic dry weight are produced annually, and inPhotosynthesis absorbs 170 billion tons of carbon dioxide. In the process of vital activity of microorganisms, 6 billion tons of nitrogen and 2 billion tons of phosphorus, as well as a huge amount of iron, magnesium, sulfur, calcium and other elements are involved in the biogenic cycle every year. During this time, humanity produces about 100 billion tons of minerals.
In the course of their life, organisms make a significant contribution to the circulation of substances, stabilizing and transforming the biosphere, the properties and structure of which make one think about the presence of higher powers.
Energy function
After getting acquainted with the structure and composition of the biosphere, let's move on to its functions. Let's start with energy. As you know, plants absorb solar radiation and saturate the biosphere with vital energy. Approximately 10% of the captured light is used by producers for their needs (mainly for cellular respiration). Everything else is distributed through food chains throughout all ecosystems of the biosphere. Part of the energy is conserved in the bowels of the earth, saturating them with its power (coal, oil, etc.).
Even considering the functions and structure of the biosphere briefly, they always single out the redox function as a subspecies of energy. Being producers, chemosynthetic bacteria can extract energy from the reactions of oxidation and reduction of inorganic compounds. In the process of hydrogen sulfide oxidation, sulfur bacteria feed on energy, and iron (from 2-valent to 3-valent) - iron bacteria. Nitrifying also do not sit withoutaffairs. They oxidize ammonium compounds to nitrates and nitrites. That is why farmers fertilize their fields with ammonium compounds, which are not absorbed by plants on their own. When fertilizing the soil directly with nitrates, the storage tissues of plants are oversaturated with water, which leads to a deterioration in their taste and an increase in the risk of digestive diseases in those who eat them.
Environment-forming function
Living organisms form the soil, and also regulate the composition of the air and water shells of the earth. If photosynthesis did not exist on the planet, the supply of atmospheric oxygen would be used up in 2000 years. In addition, literally in one century, due to an increase in the concentration of carbon dioxide in the air, organisms would begin to die. In one day, a forest can absorb up to 25% of carbon dioxide from a 50-meter layer of air. A medium-sized tree can provide oxygen for four people. One hectare of deciduous forest, located near the city, annually retains about 100 tons of dust. Lake Baikal, which is famous for its crystal clearness, is so thanks to small crustaceans that “filter” it three times a year. And these are just a few examples of how living organisms regulate the composition of substances in the biosphere.
Concentration function
Living beings, and especially microorganisms, are able to concentrate many chemical elements found in the biosphere. Almost 90% soil nitrogenare the result of the activity of blue-green algae. Bacteria can concentrate iron (for example, by oxidizing water-soluble bicarbonate to hydroxide deposited in their environment), manganese, and even silver. This amazing feature allowed scientists to believe that it is thanks to microorganisms that there are so many metal deposits on earth.
In some countries, elements such as germanium and selenium are extracted from plants. Fucus algae can accumulate 10,000 times more titanium than is contained in the surrounding seawater. Each ton of brown algae contains several kilograms of iodine. Australian oak accumulates aluminum, pine - beryllium, birch - barium and strontium, larch - niobium and manganese, and thorium is concentrated in aspen, bird cherry and fir. In addition, some plants even "collect" precious metals. So, in 1 ton of wormwood ash there can be up to 85 grams of gold!
Destructive function
The chemical structure of the Earth's biosphere and its environment involves not only creative, but also destructive processes. However, they also play a big role in the regulation of substances on the planet. With the active life of living organisms, the mineralization of organic residues and the weathering of rocks occur. Bacteria, fungi, blue-green algae, and lichens can break down hard rocks by releasing carbonic, nitrous, and sulfuric acids. Corrosive compounds also release tree roots. There are bacteria that can even destroy glass and gold.
Transport function
Considering the structure andfunctions of the biosphere, one cannot lose sight of the mass transfer of matter. A tree raises water from the earth into the atmosphere, a mole throws the earth up, a fish swims against the current, a swarm of locusts migrates - all this is a manifestation of the transport function of the biosphere.
Living matter can do tremendous geological work, forming a new image of the biosphere and actively participating in all its processes.
Separately it is worth noting the process of formation of sedimentary rocks. The first stage of this process is weathering - the destruction of the upper layers of the lithosphere under the action of air, sun, water and microorganisms. Intruding into the rock, the roots of plants can destroy it. The water that seeps into the cracks formed by the roots dissolves and carries away the substance. This is due to the corrosive components of the plant. Lichens are especially abundant in organic acids. Thus, physical weathering occurs along with chemical weathering.
Due to the death of plankton organisms, up to 100 million tons of limestone is deposited annually on the bottom of the world's oceans. Many of them are of chemical origin, being, for example, in the area of contact between acidic and alkaline groundwater. With the death of unicellular algae and radiolarians, silicon-containing silts are formed that cover hundreds of thousands of km2 of the seabed.
Soil-forming function
The properties and structure of the biosphere are so comprehensive that all its functions are closely related. Thus, soil formation is one of the branches of mass exchangeand environmental formation, but is considered separately due to its importance. During the destruction and further processing of rocks by microorganisms, a loose, fruitful shell of the earth is formed, called soil. The roots of large plants extract mineral elements from deep horizons, enriching the upper layers of the soil with them and increasing their fruitfulness. The soil receives organic compounds from the dead roots and stems of plants, as well as excrement and carcasses of animals. These compounds are food for soil organisms that mineralize organic matter, producing carbon dioxide, organic acids and ammonia.
Invertebrates, insects, as well as their larvae, play the most important structure-forming role. They make the soil loose and suitable for plant life. Vertebrate animals (moles, shrews and others) loosen the earth, contributing to the successful growth of shrubs in it. At night, chilled compressed air penetrates the ground, which is necessary for the respiration of roots and microorganisms.
Such an amazing structure of the biosphere.
