The underwater world of the seas and oceans has always been of interest to people. After all, it is very useful and curious to know what types of plants and animals are represented? Therefore, for many decades, various scientists have been conducting thorough research in this area. A huge amount of diverse information has accumulated; a person has learned to use practically all known types of marine plants and animals for his needs.
One of such representatives, useful and significant in the economic activity of people, was brown algae. We’ll talk about them in more detail.
The systematic position of brown algae
The brown algae class occupies a fairly voluminous part of the entire flora of the seas. Today, there are about one and a half thousand species of representatives united in 250 genera. All of them are multicellular, and most often quite impressive sizes.
The general plan of the systematic position occupied by brown seaweed can be represented as follows:
- Empire - Cellular.
- Advocacy - Eukaryotes.
- Kingdom - Plants.
- Sub Kingdom - Algae or Lower Plants.
- Department - Ochrophyte Algae.
- Class - Brown Algae.
Among brown algae, plants of both small sizes and true giants are found. Consider what features they have in the structure of the body and who belongs to them.
General building plan
The structure of brown algae is not much different from that of the rest of their relatives. The body is represented by a thallus or thallus, is not differentiated into parts, has no leaves and roots. The attachment organs to the substrate are special outgrowths resembling small tentacle roots, called rhizoids.
The vast majority of life spends, attaching to the substrate. However, there are representatives floating on the surface. A feature of the thallus can be called well-defined large sheet plates. Sometimes they have very strong dissections, which makes the structure of brown algae look like threads. Therefore, often some representatives are called filamentous.
The chemical composition of the cells of these plants includes special pigment substances contained in chloroplasts. It:
- fucoxanthin;
- chlorophyll;
- xanthophyll.
They are designed to absorb individual spectra of solar radiation, which are able to penetrate to great depths in the thickness of the sea. Also, the pigments of these species give an appropriate brown color. Due to this, these algae can live at a depth of up to 200 m, although they still prefer coastal zones and a depth of at least 15 m.
The cell walls contain a special acid - alginic acid, which is one of the reasons for the production of these algae by humans. Among brown algae, there are plants on which special lumps are formed, filled with air. This is necessary in order to stay afloat at the surface of the water, and also so that germ cells for reproduction can freely develop inside.
The process of abandonment of the offspring is of three types:
- Asexual, through argument.
- Sexual, with gametes.
- Vegetative, parts of the body.
Another interesting substance that is part of the thallus of brown algae is fucoidan. This is a polysaccharide of complex structure, which has a wide range of therapeutic effects (antitumor agent, anti-inflammatory, antibacterial, immunomodulatory). This is another reason people get brown algae.
Places of distribution
Brown algae includes species that prefer the sea. However, representatives of the four genera prefer to live in fresh water - Heribaudiella, Pleurocladia, Bodanella and Sfazelyariya.
These plants are found everywhere in all the seas of the globe, but their maximum concentration falls on bodies of water of temperate latitudes, as well as zones of the Arctic. Individual representatives form a significant part of the solonchak flora.
It should be noted that brown algae includes giants who have chosen the Atlantic Ocean for their habitat. They formed a whole sea there, named after them Sargassovo. These are sargassum algae.
That is, climatic conditions are not so important for the life of such plants, so their distribution is so widespread and massive.
Representatives of the class: macrocystis
Brown algae includes macrostructures, the most striking example of which are macrocystis. These are one of the largest and most massive representatives of these plants. The length of the thallus reaches 60 m, and the mass of the culture is equal to 150 kg.
They are distributed mainly in the waters of the temperate zone. The structural features include wide leaf-shaped thalli and balloons on them, which serve as a float for holding at the surface. Rhizoids are also present on the thallus, these plants are attached to rocky and stony substrates at a depth of about 25 m.
The composition of thallus cells includes many useful and important substances for humans, which he widely uses to extract macrocystis. What are these substances?
- Polysaccharides and amino acids - used in the cosmetology industry to add to creams, tonics, lotions and so on.
- Iodine, silicon, phosphorus and other elements.
- Alginic acid - used in the chemical industry to obtain artificial fibers and tissues.
Algae itself systematically belongs to the genus Laminaria.
Analipus japanese
The plant that makes up the Hordaria brown algae family. Representatives of this taxon have a vertical thallus of not too high size. So, the analipus reaches 30 cm in length. At the same time, side branches depart from the main axis, but, as a rule, they do not branch further.
Rhizoids are tucked into the sole, with the help of which the plant is attached to stones in the coastal zones of the Pacific Ocean and adjacent territories. Common view for Sakhalin, Kamchatka, the Sea of Japan and the coast of the Kuril Islands.
Tall of this algae is multi-nest; it develops throughout life. In habitats with strong surfs, the algae takes the form of a plant pressed to the bottom, more like a crust.
Kelp
Also important is the brown algae of kelp, a representative of the same genus. It consists of numerous species, the main of which is Japanese Laminaria or Sea Kale. This plant is common in the Pacific and Atlantic Ocean and is of great value to humans.
The body structure is represented by a long, up to 12 m tall, having the form of a wide brown ribbon. Rhizoids at the bottom of the thallus are used for attachment to stony and rocky substrates.
How is kelp useful to people?
- Methionine is an amino acid by the content of which this plant is a champion even among land vegetables.
- Minerals, iodine, trace elements - are present in large quantities in the cells of kelp.
- Carbohydrates give this plant high nutritional value.
Due to this composition, kelp is used for animal feed, used as a valuable product for people, known for its properties in cosmetology and nutrition.
Fucus
The following representatives are very valuable from a medical point of view - fucus (fucus). Their other name is "sea grapes", which they received for the interesting structure of the thallus. It is very palmate-dissected and resembles clusters of this fruit. These plants are a storehouse of all possible nutrient and important substances that generally contain brown algae. Representatives number about 19 taxa.
Outwardly, the thallus is low, olive in color, quite massive, dense. Plants habitat: almost all seas and oceans, especially the White Sea.
Substances that are part of and have value:
- about 42 chemical elements;
- amino acids and fatty acids;
- vitamins from group A to PP;
- fucoidan.
Sargassum
Brown algae also includes plants such as sargassum. Tall reaches a length of up to 10 m, a feature is considered to be the ability to form air cones, bubbles on the tops. Thanks to this, plants form entire thickets at the surface of the water (in the part of the Atlantic Ocean, the Sargasso Sea). Attached to the rocky bottom surfaces.
The main areas of application of these species to human food (Asian countries), animal feed, the extraction of medicinal substances. Habitats: tropical zones.
Pads
Very interesting brown algae, the color of which is far from the name of the class. More closely resemble white mushrooms of a wavefish with their beautiful fan-shaped small thallus. This plant is very thermophilic, therefore it is common in tropical zones and off the coast of America. It is used mainly in medicine and cosmetology.