Physics in the animal world: diatoms and their "architecture"

Diatoms are single-celled and colonial algae, which are characterized by the presence of a protective shell of silicon dioxide cells. Diatoms live in both sea and fresh water. According to experts, such algae create about a quarter of organic matter on Earth.

The form of diatoms is very diverse. Usually diatoms are shell, inside and outside of which there is a relatively small layer of organic matter. The skeleton of the cell structure is different in the pennatal and centric regions. The first group has bilateral symmetry, the second - radial. The name algae comes from the Greek word diatomos (“cut into two parts”). The fact is that the shells of diatoms are divided into two halves (more on this - below).

If only one axis of symmetry can be drawn through the shell of the armor, such symmetry can be called two-sided symmetric. The shell usually consists of two halves, with the larger half covering the smaller one. The shell of diatoms consists of a silica cover. There are few additional elements like iron, aluminum, magnesium and a number of organic substances. The thickness of the shell walls depends on the concentration of silicon in the medium and varies considerably: in thin-walled forms it varies from hundredths to tenths of a micrometer, and in thick-walled forms it reaches 1-3 microns. The walls of the shell are permeated with the smallest holes that provide for the exchange of substances between the protoplast and the environment. They are also equipped with various shaped elements that make up the structure of the shell and serve as the main taxonomic features in the construction of a system of diatoms. The shell and its structure are distinguishable even at a slight magnification of the microscope.
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However, the details of the silica shell structure are not so easy to figure out. For an idea of ​​the shape of the shell of diatoms, the ratio of axes and planes of symmetry must be taken into account.

Much is known about the diatom lifestyle. Diatoms live quite well in a variety of ecosystems and biotopes. Algae live in both oceans and seas, and brackish and fresh water bodies. They are in the ground, the air, they were found in the ice of the Arctic and Antarctic. These algae are well adapted to a variety of environmental factors. Recently, when deciphering the full genome of the Phaeodactylum tricornutum diatom, it turned out that it contains a record number of genes for eukaryotes, obtained by horizontal transfer from bacteria and archaea. Now it is believed that about 300 genera belong to the class of diatoms, which include 20-35 species.

Even specialists may find it difficult to separate one species of diatoms from another. In order to correctly identify diatoms, scientists use a shell pattern after removing the protoplast. Experts say that the shell of diatoms and the nature of ornamentation is one of the most important moments in identification. The shape of the shell of the algae is symmetrical in all three dimensions. The top and bottom of the algae skeleton almost perfectly fit together.


Diatoms are very different, and scientists have yet to find out a lot of interesting facts about these algae. The pictures show both diatoms and ornaments that are laid out of them.

From diatoms still in the Victorian era began to spread ornaments. Due to the fact that the algae themselves are microscopic, ornaments are not visible to the naked eye, they are made up under a microscope. And under the microscope, they then admire their work. This careful work is done using the finest needle.


Interestingly, diatoms are an important component of the nutrition of whales. Thus, a medium sized whale can eat several hundred kilograms of diatoms at a time.

Despite the fact that diatoms are very small - their sizes are about a quarter of the diameter of a human hair, these algae have a “design” perfect from the designer’s point of view. All diatom bodies are symmetrical in three dimensions, with the upper part and the bottom of the diatom almost perfectly fit together.

Algae are so dependent on silicon dioxide that if the concentration of silica in a particular region is rather low, diatoms will not divide. One of the sources of silica is Si (OH) ₄ , which enters the alga through the silicic acid transport proteins. Unfortunately, scientists can not yet figure out how the delivery of silica into the cell. Scientists believe that Si (OH) ₄ and Na are transported by algae in a 1: 1 ratio.

During cytokinesis, the cell membrane creates a constriction, but the Golzhi complex starts, starting to reproduce the so-called vesicles. They are always preserved in newly formed cells.

Interestingly, the forms of the shell of diatoms very much. They can resemble discs and cylinders of tubes and balls, drums and clubs. Also original is the fact of the diversity of the forms of the valves (round, oval, lancer, linear, rhombic guitar-like, 5-shaped, and others).

The shell structure of many diatom species is ideal from the point of view of the architect. Some buildings were built following the example of the hull of this seaweed. One such example is the construction of the Berlin Theater. Its creators used the form of diatom algae in the construction of the support of the Berlin Theater. Interestingly, the proportions were taken without any special changes and calculations. The shell of the diatom is unusually strong, although porous. Scientists hope to explore it thoroughly in order to be able to repeat the trick with "perforated structures", where the holes will increase the strength and resistance of the shell.