Primary production: concept, features, research

2024 Author: Howard Calhoun | [email protected]. Last modified: 2023-12-17 10:16

Primary production is a certain value in ecology. The method for its measurement was invented by the Soviet hydrobiologist Georgy Georgievich Vinberg in the first half of the 20th century. The implementation of the first experiment was carried out near Moscow.

Concept

In his concept, A. N. Leontiev introduces the term "primary production". It denotes a certain value in ecology, which determines the increase in the amount of organic matter formed over a certain time by autotrophic organisms from simple inorganic components. The calculation of primary production takes place over a set period of time, the length of which is determined by biologists.

Autotrophic organisms

These are organisms that are able to use inorganic substances to produce organic ones. Autotrophs are on the first tier of the food pyramid, as they are the primary producers of organic matter in the biosphere. Thanks to these organisms, heterotrophs (those organisms that cannot obtain organic elements from inorganic ones with the help ofphotosynthesis or chemosynthesis) are provided with food.

There are organisms that simultaneously belong to two species: green euglena algae at night belongs to heterotrophs, and during the day - to autotrophs. Such organisms are called "mixotrophs".

How is this value estimated?

To calculate this value, it is necessary to measure the amount of carbon that has been bound by plants growing on the earth and phytoplankton living in the ocean over a certain time. All this is calculated per unit area.

Sometimes, as in the case of phytoplankton, primary production is estimated within small time periods, most often a day. This is because this organism has a high rate of formation of organic matter, which is calculated per unit of biomass (the totality of plants and animals that are part of a biogeocenosis of any size and level).

If we consider the time over which the primary production of terrestrial plants is measured, then this will be one year or the growing season (the period of the year during which certain living plant organisms are susceptible to development). Such a duration of evaluation is explained by the fact that the rate of transformation of inorganic substances into organic substances in this type of organisms is much slower than in plankton.

For whom does the concept of primary production apply?

This value is calculated for photoautotrophic and chemoautotrophic organisms. For the first source of energy is sunlight, andthe latter produce organic substances from inorganic substances using redox reactions with simple substances that they themselves create. Few organisms are capable of the second way of obtaining energy, these include bacteria, some prokaryotes (single-celled, which have a nucleus and membranes in the cell).

In the modern world, the role of chemoautotrophs is small. They are of the greatest importance in hydrothermal ecosystems (oases of life, which are located at a considerable depth in the ocean, where there are cracks in the crust with hot waters coming out of them, rich in reduced compounds), although the primary production there is not estimated in very large quantities, but the importance her great.

Gross value

Researchers divide the primary production of ecosystems into gross and net.

The first term refers to the amount of total organic matter produced by the producer.

To the net primary value are received organic substances, taking into account the deduction of the costs that are required by the producing organism to perform the activity of respiration. It is this type of quantity that is the substance that consumers can use for their needs, in other words, pure primary production is the basis for supporting the trophic chain (a series of relationships between different organisms, through which various types of energy and matter are transferred by eating some individuals others).

Research

Initially, GG Vinberg carried out accounting of primary production on the lake using the method of "dark and light flasks". It consisted in comparing the amount of organic substances obtained and the amount of oxygen released during photosynthesis. Later, the researchers found that this method of estimating primary production is unreliable, since it has a reduced sensitivity. Therefore, the biologist E. Steman-Nielsen proposed an alternative "radiocarbon method". With this method, carbon dioxide and a radioactive isotope of carbon were added to water samples containing plankton. Later, the amount of organic matter was calculated based on the radioactive carbon associated with it.

Research in this area, since the 60s of the XX century, has been carried out around the world, and they do not stop until now, pleasing scientists with new discoveries.