Finding oxygen in nature. The cycle of oxygen in nature

Since the appearance of chemistry, mankind has realized that everything around consists of a substance that includes chemical elements. The variety of substances is provided by various compounds of simple elements. To date, 118 chemical elements have been discovered and included in D. Mendeleyev's periodic table. Among them is a number of leading figures, the presence of which determined the appearance of organic life on Earth. This list includes: nitrogen, carbon, oxygen, hydrogen, sulfur and phosphorus.

Oxygen: the history of discovery

All these elements, as well as a number of others, contributed to the evolution of life on our planet in the form in which we are now observing. Among all the components of oxygen it is more in nature than other elements. Oxygen as a separate element was discovered on August 1, 1774 by Joseph Priestley. In an experiment to obtain air from the scale of mercury by heating with a conventional lens, he discovered that the candle burns with an unusually bright flame.

For a long time Priestley tried to find a reasonable explanation for this. At that time, this phenomenon was given the name "second air". Earlier, the inventor of the submarine K. Drebbel at the beginning of the 17th century isolated oxygen and used it for breathing in his invention. But his experiments did not influence the understanding of what role oxygen plays in the nature of the energy exchange of living organisms. However, scientists who officially discovered oxygen, recognized the French chemist Antoine Laurent Lavoisier. He repeated Priestley's experiment and realized that the resulting gas is a separate element.

Oxygen interacts with virtually all simple and complex substances, except for inert gases and noble metals.

Finding oxygen in nature

Of all the elements of our planet, oxygen is the largest. The distribution of oxygen in nature is very diverse. It is present both in a connected form and in a free form. As a rule, being a strong oxidizer, it stays in a bound state. The presence of oxygen in nature as a separate unbound element is fixed only in the atmosphere of the planet.

Contained in the form of gas and is a combination of two oxygen atoms. It is about 21% of the total volume of the atmosphere.

Oxygen in the air, in addition to its usual form, has an isotropic form in the form of ozone. The ozone molecule consists of three oxygen atoms. The blue color of the sky is directly related to the presence of this compound in the upper layers of the atmosphere. Thanks to ozone, the hard short-wave radiation from our Sun is absorbed and does not get to the surface.

In the absence of an ozone layer, organic life would be destroyed, like roasting food in a microwave oven.

In the hydrosphere of our planet, this element is in a connected form with two molecules of hydrogen and forms water. The proportion of oxygen in the oceans, seas, rivers and groundwaters is estimated at about 86-89%, taking into account the dissolved salts.

In the earth's crust, oxygen is in a bound form and is the most common element. Its share is about 47%. The presence of oxygen in nature is not limited to the shells of the planet, this element is part of all organic beings. Its share on average reaches 67% of the total mass of all elements.

Oxygen is the basis of life

Because of the high oxidative activity, oxygen is easily combined with most elements and substances, forming oxides. The high oxidizing power of the element provides for all the known combustion process. Oxygen is also involved in slow oxidation processes.

The role of oxygen in nature as a strong oxidant is indispensable in the process of vital activity of living organisms. Due to this chemical process, oxidation of substances takes place with the release of energy. Its living organisms use for their vital functions.

Plants - the source of oxygen in the atmosphere

At the initial stage of the formation of the atmosphere on our planet, the existing oxygen was in a bound state, in the form of carbon dioxide (carbon dioxide). Over time, there were plants that can absorb carbon dioxide.

This process became possible due to the appearance of photosynthesis. With time, during the life of plants, for millions of years in the Earth's atmosphere accumulated a large amount of free oxygen.

According to scientists, in the past, its mass share reached about 30%, 1.5 times more than now. Plants, both in the past and now, significantly influenced the cycle of oxygen in nature, thus ensuring the diverse flora and fauna of our planet.

The importance of oxygen in nature is not just huge, but paramount. The metabolic system of the animal world is clearly based on the presence of oxygen in the atmosphere. In his absence, life becomes impossible in the form in which we know. Among the inhabitants of the planet will remain only anaerobic (able to live without the presence of oxygen) organisms.

The intensive cycling of oxygen in nature is ensured by the fact that it is in three aggregate states in association with other elements. Being a strong oxidizer, it very easily passes from free form to bound. And only because of plants that split carbon dioxide by photosynthesis, it is in free form.

The process of breathing animals and insects is based on obtaining unbound oxygen for oxidation-reduction reactions with the subsequent production of energy to ensure the vital activity of the organism. The presence of oxygen in nature, bound and free, provides a full life activity of all life on the planet.

The evolution and "chemistry" of the planet

The evolution of life on the planet relied on the features of the composition of the Earth's atmosphere, the composition of minerals and the presence of water in the liquid state. The chemical composition of the crust, atmosphere, and water availability have become the basis for the origin of life on the planet and have determined the direction of evolution of living organisms.

Based on the available "chemistry" of the planet, evolution has come to carbon organic life on the basis of water as a solvent of chemicals, as well as the use of oxygen as an oxidant to generate energy.

A different evolution

At this stage, modern science does not disprove the possibility of life in other environments different from terrestrial conditions, where silicon or arsenic can be used as the basis for constructing an organic molecule. A fluid medium, as a solvent, can be a mixture of liquid ammonia and helium. As for the atmosphere, it can be represented as gaseous hydrogen with an admixture of helium and other gases.

What metabolic processes can be under such conditions, modern science is not yet able to model. However, this direction of the evolution of life is entirely permissible. As time proves, humanity is constantly confronted with the expansion of the boundaries of our understanding of the world around us and life in it.