In our article, we will consider which organisms undergo chemosynthesis. This is one of the ways in which living organisms are found in nature in some bacteria.
Methods of feeding organisms
To understand what chemosynthesis is, you must first remember what methods of nutrition are used by various organisms. On this basis, two groups of creatures are distinguished: hetero and autotrophs. The former are able to eat only prepared organic substances. They absorb and convert proteins, fats and carbohydrates with the help of specialized vacuoles or digestive organs. Heterotrophs are animals, fungi, and some bacteria.
Types of autotrophs
Autotrophic organisms themselves synthesize organic substances, which are subsequently used to carry out various processes of life. Depending on the energy source that is used, two more groups of organisms are distinguished. These are photo and chemotrophs. Representatives of the first of these are plants. They synthesize carbohydrate into glucose during photosynthesis. This process occurs only in green plastids of chloroplasts in the presence of sunlight, water and carbon dioxide. Chemotrophs are some bacteria. For the synthesis of organics, they need various chemical compounds that they oxidize. The similarities between photosynthesis and chemosynthesis are the ability of organisms to independently form the substances they need, receiving carbon, water and mineral salts from the environment.
Chemosynthesis: definition and history of discovery
Let's take a closer look. What is chemosynthesis? This is one of the methods of autotrophic nutrition, in which the process of oxidation of mineral compounds for organic synthesis takes place. Now find out which organisms chemosynthesis occurs. Only some types of prokaryotes possess such a unique ability in nature. This process was discovered at the end of the 19th century by the Russian microbiologist Sergei Nikolaevich Vinogradsky. Working in the laboratory of Anton de Bari in the Strasbourg laboratory, he carried out an experiment on obtaining energy through the oxidation of sulfur. Organisms that are capable of carrying out this chemical process, he called anorgoxidants. In the course of his research, the scientist was able to discover nitrogen-fixing bacteria. Prior to the discovery of the chemosynthesis process, only photosynthetic plants and blue-green algae were classified as autotrophic organisms.
Differences and similarities of photosynthesis and chemosynthesis
Both types of autotrophic nutrition are plastic exchange, or assimilation. This means that during these processes, the formation of organic substances and gas exchange. In this case, the initial reagents are mineral compounds. Photo- and chemosynthesis are ways of carrying out the circulation of substances in the biosphere. All types of autotrophs provide the conditions necessary for life, not only themselves, but also other organisms. For example, oxygen is released during photosynthesis. It is necessary for all living things to breathe. And chemotrophic nitrifying bacteria transform atmospheric nitrogen into a state in which it can be absorbed by plants.
But there are a number of differences between these types of food. Chemosynthesis occurs in bacterial cells that do not contain the green pigment chlorophyll. Moreover, for oxidation, they use compounds of only certain substances: sulfur, nitrogen, hydrogen or iron. This way of eating is especially important in places where sunlight is not available. So, only chemotrophs can dwell at great depths. For the process of photosynthesis, solar energy is a prerequisite. Moreover, in plants, this process occurs only in specialized cells containing the green pigment chlorophyll. Another prerequisite for phototrophic nutrition is the presence of carbon dioxide.
Iron bacteria
What is chemosynthesis, you can consider the example of bacteria that convert iron compounds. Their discovery also belongs to S. N. Vinogradsky. In nature, they are widespread in fresh and salt bodies of water. The essence of their chemosynthesis is to change the valency of iron from two to three. A small amount of energy is released. Therefore, iron bacteria have to carry out this process very intensively.
Since bacteria are one of the most ancient organisms, as a result of their life on the planet, large deposits of iron and manganese ores have formed. In industry, these prokaryotes are used to produce pure copper.
Serobacteria
These prokaryotes reduce sulfur compounds. In the study of these particular organisms, the process of chemosynthesis was discovered. For the oxidation of this type of bacteria uses hydrogen sulfide, sulfides, sulfates, polythionates and other substances. And some prokaryotes of this group accumulate elemental sulfur during chemosynthesis. This can occur both in cells and outside of them. This ability is used to solve the problem of additional aeration and soil acidification.
The natural habitat of sulfur bacteria is fresh and salt bodies of water. There are known cases of the formation of symbioses of these organisms with tubular worms and mollusks that live in silt and the bottom zone.
Nitrogen fixing bacteria
The importance of chemosynthesis in nature is largely determined by the activity of nitrogen-fixing prokaryotes. Most of them live on the roots of legumes and cereal plants. Their cohabitation is mutually beneficial. Plants provide prokaryotes with carbohydrates that were synthesized during photosynthesis. And bacteria produce nitrogen, which is necessary for the full development of the root system.
Before the discovery of the valuable properties of this species, it was believed that legume leaves had a unique ability. Later it turned out that plants do not directly participate in the process of nitrogen fixation, and the process is carried out by bacteria that live in their roots.
This type of prokaryote carries out two types of chemical reactions. As a result of the first, ammonia is converted to nitrates. Solutions of these substances enter the plant using the root system. Such bacteria are called nitrifying. Another group of such prokaryotes turns nitrates into nitrogen gas. They are called denitrifiers. As a result of their combined activity, there is a continuous cycle of this chemical element in nature.
Nitrogen-fixing bacteria penetrate the roots of plants in places of damage to integumentary tissues or through the hairs of the absorption zone. Once inside, prokaryotic cells begin to actively divide, as a result of which numerous protrusions form. They are visible to the naked eye. A person uses the property of nitrogen-fixing bacteria to provide the soil with natural nitrates, which leads to increased productivity.
Nature and chemosynthesis
The role of chemosynthesis in nature is difficult to overestimate. The process of oxidation of inorganic compounds in nature is an important component of the general circulation of substances in the biosphere. The relative independence of chemotrophs from the energy of sunlight makes them the only inhabitants of the deep-sea basins and rift zones of the ocean.
Ammonia and hydrogen sulfide, which are processed by these prokaryotes, are toxic substances. In this case, the importance of chemosynthesis is to neutralize these compounds. The term “underground biosphere” is known in science. It is formed solely by organisms that do not need light or oxygen for life. Anaerobic bacteria have this unique property.
So, in the article we figured out what chemosynthesis is. The essence of this process is the oxidation of inorganic compounds. Chemosynthetic organisms are some types of prokaryotes: sulfur, iron bacteria and nitrogen-fixing.