Brown algae in an aquarium. Brown algae - structure and reproduction, features and causes of occurrence All about brown algae

There are 250 genera and about 1500 species. The most famous representatives are kelp, cystoseira, sargassum.

These are mainly marine plants, only 8 species are secondary freshwater forms. Brown algae They are widespread in the seas of the globe, reaching particular diversity and abundance in cold water bodies of subpolar and temperate latitudes, where they form large thickets in the coastal strip. In the tropical zone, the largest accumulation of brown algae is observed in the Sargasso Sea; their massive development usually occurs in winter, when the water temperature drops. Vast underwater forests are formed by kelp algae off the coast of North America.

Brown algae are usually attached to hard substrates, such as rocks, rocks, mollusk shells, and other algae thalli. In size they can reach from several centimeters to several tens of meters. The multicellular thallus is colored from olive green to dark brown, since the cells, in addition to chlorophyll, contain a significant amount of brown and yellow pigments. These plants have the most complex structure of all algae: in some of them, the cells are grouped in one or two rows, which resembles the tissues of higher plants. Species can be either annual or perennial.

Thallus. In algae of this group, thalli can be of various shapes: creeping or vertically “hanging” threads, plates (solid or cut up) or branching bushes. The thalli are attached to the solid substrate by means of rhizoids (soles). Higher brown algae of the order Laminaria and Fucus are characterized by differentiation of tissue structures and the appearance of conducting systems. Unlike algae of other groups, brown algae are characterized by the presence of multicellular hairs with a basal growth zone.

Cell structure . The cover is a thick cell wall, consisting of two or three layers, highly mucus-producing. The structural components of the cell wall are cellulose and pectin. Each cell of brown algae contains one nucleus and vacuoles (from one to several). Chloroplasts are small, disc-shaped, and brown in color due to the fact that in addition to chlorophyll and carotene, they contain a high concentration of brown pigments - xanthophylls, in particular fucoxanthin. Also in the cytoplasm of the cell, reserves of nutrients are deposited: the polysaccharide laminarin, polyhydric alcohol mannitol and various fats (oils).

Propagation of brown algae . Reproduction is carried out asexually and sexually, rarely vegetatively. The reproductive organs are sporangia, both unilocular and multilocular. Usually there is a gametophyte and a sporophyte, and in higher algae they alternate in strict sequence, while in lower algae there is no clear alternation.

Meaning. The importance of brown algae in nature and human life is great. They are the main source of organic matter in the coastal zone of the seas. In the thickets of these algae, which occupy vast areas, many marine inhabitants find shelter and food. In industry, they are used in the production of alginic acids and their salts, to obtain feed flour and powder for the manufacture of medicines containing high concentrations of iodine and a number of other microelements. In aquariums, the appearance of brown algae is associated with insufficient lighting. Some species are eaten.

Life originated in the World Ocean. That's exactly what he thinks modern science. You may have your own point of view on the origin of life, but we are talking about something else now.

Many seafood products have unique healing properties- and this is an indisputable fact. Therefore, everyone who cares about their health and appearance should definitely get acquainted with at least the most common and affordable products - seaweed (kelp, spirulina and cabbage).

However, we are sure that you have definitely tried one of the above at least once in your life. And, perhaps, they have already formed their attitude towards them, as with any product. If you're a big seafood fan, you'll be pleased to have your passion confirmed. If you use the above occasionally, then perhaps our information will be useful to you. Well, if someone still couldn’t overcome the specific sensations... well, there’s no need to force yourself, read on anyway, because it’s important to use seaweed not only in its natural form and not only for food...

Based various signs There are ten types of algae:

  • Reds.
  • Brown.
  • Polyflagellates.
  • Diatoms.
  • Pyrophytae.
  • Golden.
  • Blue-green.
  • Harovs.
  • Yellow-green.

Moreover, all types evolved independently of each other.

Application of brown and red algae

Brown algae

Kelp- brown algae from the seas of the Pacific and Arctic oceans. Its main thickets are at a depth of four meters to ten meters. The thallus (body) of kelp is very wide and large. Sometimes reaches up to 20 m in length. It is no coincidence that kelp among the people received the name “sea kale”; it is widely used in food, both fresh and dried, canned.

Kelp is one of the main components for making sushi and rolls.

For the treatment of a number of diseases (goiter, atherosclerosis, colitis, constipation), kelp is used in powder form. A granular preparation is produced in tablets “Lamminaride”.

Fucus vesicularis- a coastal algae of the seas of the Arctic and Atlantic oceans. The content of nutrients is not inferior to seaweed.

The use of fucus powder is indicated for diseases:

  • immune system
  • obesity
  • disorders in the gastrointestinal tract
  • Treatment of obesity is based on the ability to fill the stomach, causing feelings of fullness and satiety.

Laminaria and fucus are used to produce natural thickeners - alginates:

  • E 401, sodium alginate
  • E 402, potassium alginate

Alginates are necessary in the production of many antacids to neutralize hydrochloric acid in gastric juice.

Alginic acid masks are widely used in cosmetology.

Excessive consumption of drugs and food products with brown algae can be harmful to people with thyroid diseases and iodine metabolism disorders.

Red algae

Anfeltsia- a representative of the scarlet fish, lives in many outer seas of the north and Far East, found in the Black Sea. It looks like low branched, tough bushes of red or yellow color. Lives at a depth of up to 5 meters in coastal areas. Grows in bunches or spherical formations.

The main purpose is the production of a natural thickener - agar - agar. Food additive E 406 (agar - agar) is the main gelling agent in the production of marmalade, pastille, soufflé. In some countries it replaces gelatin.

It is used as a nutrient medium for the inoculation and growth of many pathogenic microorganisms.

IN folk medicine In many coastal countries, ahnfeltsia is used as an antitumor agent for breast cancer.

Uncontrolled consumption of ahnfeltia products can be harmful to patients with various forms of diarrhea.

Gracilaria- a red algae that lives in many, mainly warm seas. Distinctive property from ahnfeltia is a high growth rate and suitability for cultivation as mariculture. Scientists from the Primorsky region have achieved great success in growing gracilaria.

As a raw material for the production of agaroids, coastal gracilaria plantations can saturate the raw material market for natural thickeners.

Black Sea mariculture

Phyllophora ribbed- red algae of the Black Sea. Widely cultivated for the production of agaroids. Large thickets are located near Odessa. Like gracilaria, it prefers those places where freshwater rivers flow into the sea. On the Black Sea northwestern coastal shelf it forms an entire underwater jungle.

The chemical iodine was first obtained in 1813 from the production of sodium nitrate from red algae. And since natural deposits of nitrate were in Chile, iodine production was organized there. In those years, European iodine was obtained only from red algae, which over time could not withstand competition with Chilean production.

In Russia, in 1915, a plant for the production of iodine in the city of Ekaterinoslav (Dnepropetrovsk) operated on the Black Sea phyllophora. In the production of agaroids, the Odessa plant produces the most valuable powder from aminopeptides, which has found application in the production of many cosmetics slowing down aging.

The use of powder and emulsion from gracilaria and phylloflora in the production of food and cosmetics does not harm the body, except in cases of individual intolerance.

Extract from Ireland

Gigartina and Chondrus curly th are related red algae. They grow in the coastal zone of Ireland and the USA. Used to produce food thickener - carrageen. On the basis of which safe baby food is produced.

Due to the ability to restore the epidermis of the skin and make its structure smooth, extracts from gigartina and chondrius curly are widely used in the cosmetic industry.

An important property of carrageenan is its ability to prevent the penetration of human papillomavirus (HPV) into healthy cells. Research has shown that the use of red algae extract can become the main preventive measure against human papillomavirus infection. Gels and ointments based on it are inexpensive and, after clinical trials are completed, can become an alternative means of widespread use in the fight against HPV.

The benefits of preparations and food additives from seaweed can hardly be underestimated. For example, such a “sea grass” as eelgrass (kamka) is used to prepare a powder similar in its qualities to curry seasoning. But dishes with it are not only tasty, but also very healthy.

You can purchase algae products or preparations in retail and pharmacy chains, including online. To avoid fakes, pay attention to the presence of a quality certificate. If you have an individual intolerance, read the ingredients of the products; additives E 401,402,406 are made from algae.

It is important to remember that excessive consumption of even the most useful and necessary substances can cause harm. It is better to start using any medications after consulting a doctor.

Lithothamnia

Red coral algae has a rich mineral composition (it contains more than 30 minerals), contains high doses of magnesium and especially iron. For prevention and healing of the body, the recommended daily dose of algae is 20 g for fresh, fresh frozen or dry pressed product (asaka, wakame, nori, etc.).

Purple

Refers to red algae, prevents the development of atherosclerosis and reduces the level of “bad” cholesterol in the body. This type of seaweed can be recommended for heart patients as a dietary supplement. Porphyry is also rich in vitamins A, B12 and D.

Spirulina

Refers to green algae, very rich in easily digestible proteins (per 100 g of powdered product there are 60-70 g of protein). And this is three times the protein value of soybeans. Don't forget about 18 different amino acids, each of which is needed for a healthy, fulfilling life. Moreover, the body cannot synthesize 8 amino acids from this list.

It is considered one of the most popular edible seaweeds. It’s sad that only residents of the African coast of Lake Chad and Mexicans from Texcoco, the area where spirulina naturally grows, can afford it fresh. The rest have to be content with dietary supplements and semi-finished products. The nutritional value This green algae is so large that they have learned to breed it under artificial conditions (in huge vats of warm water saturated with carbon dioxide) in France and Mexico.

Ulva or sea lettuce

Refers to green algae, has long been used as food by residents of Ireland, Japan, France, China, and Scandinavia. Sea lettuce contains a lot of iron, nutritious proteins and fiber.

Properties of seaweed. The benefits of seaweed. Seaweed treatment

Biologists and doctors confidently declare that algae are superior to all other plant species in terms of the content of active substances.

Seaweed has antitumor properties.

In the chronicles different nations Numerous legends have been preserved about them. Seaweed was used not only as an excellent food product, but also as effective remedy for the prevention and treatment of various diseases.

Already in ancient China treated with seaweed malignant tumors. In India, seaweed was used as an effective remedy in the fight against certain diseases of the endocrine glands. In ancient times, in the harsh conditions of the Far North, Pomors treated various diseases with algae, and also used them as practically the only source of vitamins.

The qualitative and quantitative content of macro- and microelements in seaweed resembles the composition of human blood, which indicates our evolutionary connection with the sea, and also allows us to consider seaweed as a balanced source of saturating the body with minerals and microelements.

Seaweed contains a number of substances with biological activity:

  • lipids rich in polyunsaturated fatty acids;
  • chlorophyll derivatives;
  • polysaccharides: sulfated galactans, fucoidans, glucans, pectins, alginic acid, as well as lignins, which are a valuable source of dietary fiber;
  • phenolic compounds;
  • enzymes;
  • plant sterols, vitamins, carotenoids, macro- and microelements.
  • As for individual vitamins, microelements and iodine, there are more of them in seaweed than in other products.

Seaweeds and biologically active substances from them have antimutagenic activity, which is determined by the pigments p-carotene, chlorophyll, lutein, and radioprotective properties, which is associated with the presence of alginic acid and its salts in their composition.

Alginates are capable of selectively binding and removing heavy metal ions from the body, such as strontium and cesium, as well as other radionuclides. A feature of alginic acid preparations is their targeted correction in the most radiodamaged vital systems of the human body (hematopoietic system and gastrointestinal tract). There is evidence of the beneficial symptomatic effect of kelp in cancer patients. Experts recommend sea kale (kelp) not only for the prevention of cancer and leukemia, but also for radiation sickness. The therapeutic anti-carcinogenic effect of kelp is due to the presence of many biologically active substances and a complex of microelements in this seaweed. It is on its basis that powerful bioadditives - oncoprotectors - have been created.

Scientists have proven that algae have greater biological activity than land plants. Research shows that the Inuit (Eskimos) of Alaska and Greenland are significantly less likely to develop malignant neoplasms compared to other populations. Although the Eskimo diet is high in fat, their diet is different. big amount fish and other seafood, which cause a protective antitumor effect. Articular rheumatism, diabetes and diseases of the cardiovascular system are also almost never found among these peoples.

Scientists explain this by the presence of polyunsaturated fatty acids in their diet. They have high biological activity, are not synthesized in the human body, and are therefore irreplaceable. Polyunsaturated fatty acids of seaweed take part in the synthesis of prostaglandins, which have a huge impact on health. They are able to dilate blood vessels, lower blood pressure, expand or narrow the lumen of the bronchi, stimulate the production of hormones, and increase the sensitivity of nerve fibers. Prostaglandins play an important role in the activity of the reproductive system, in the mechanisms of fertilization and childbirth.

Brown algae and preparations made from them have a hypolipidemic effect, prevent the development of obesity, and improve the functions of the cardiovascular system. Traditional Japanese diet high in seaweed and reduced calorie content prevents the development of obesity and atherosclerosis. It has now been proven that saturating the body with Omega-3 polyunsaturated fatty acids contained in seaweed and fish oil normalizes lipid metabolism and prevents the development of atherosclerosis.

Seaweed is used for the prevention and treatment of cardiovascular diseases.

Biologically active substances in seaweed have anti-inflammatory and immunomodulatory properties. Immunocorrectors from algae increase the activity of the human immune system and enable the body to successfully fight bacterial, fungal and viral infections. A number of studies have proven antiviral activity against the human immunodeficiency virus. The high sorption activity of the drugs makes them indispensable for the prevention of allergic and autoimmune diseases. They are able to restore the functional activity of macrophages and T-lymphocytes, enhance cellular cooperation, activate the synthesis of secretory immunoglobulins-A, the deficiency of which is the basis of chronic diseases involving the mucous membranes of the respiratory tract, genitourinary system and gastrointestinal tract.

Seaweed accumulates a number of vitamins from sea water (A, C, D, vitamins B, K, PP, folic and pantothenic acids).

About the main thing: algae contains absolutely all the minerals, vitamins and amino acids necessary for the full functioning of our body. In this case, it is enough to simply regularly include standard portions of the product in your diet.

Moreover, modern medicine has come to meet those who do not quite like the taste of seaweed, and today many drugs have been created that contain seaweed (against rheumatism, migraines, diabetes). Remember, you or your friends probably strengthened their immune system with spirulina extract.

About the benefits of seaweed for weight loss

Firstly, like pineapple, brown algae (kelp, seaweed) contain a special enzyme that breaks down fats.

Secondly, you can drink algae with water or green tea. At the same time, they swell in the stomach, significantly increase in volume and eliminate the feeling of hunger for a long time.

Thirdly, algae contain a tiny amount of calories: from 7 to 15 per 100 g (depending on the type). So seaweed salad (if you do not add mayonnaise and other calories) can be eaten almost without restrictions.

Seaweed in the fight against cellulite

This advice is also very useful, especially for those who have not been able to get used to the taste of algae. This product is so good that body slimming experts find uses for it not only as food!

You guessed it, we are talking about the fight against cellulite. The procedure is extremely effective: three days after it, the volume is reduced to 7 centimeters. True, provided that you spend it in the salon.

Hot wrap (and this is the type you should choose) stimulates blood circulation, improves the appearance of the skin, helps remove toxins from the skin, reduces body volume, and wounds and scratches even heal faster.

But some experts believe that such a brilliant effect is achieved only by temporarily draining fluid from the tissues, and therefore recommend performing wraps along with other procedures: massage, myostimulation and physical activity. And if you take a special bath, your skin will become like a baby’s bottom.

Algae bath

100 g seaweed and 100 g sea ​​salt without stirring, pour into the bath. Take no more than 25 minutes.

Then, without drying yourself, wrap yourself in a terry sheet and sit like that for half an hour. After this, you should wash with warm water, dry off and apply anti-cellulite cream to the skin - always with a massage.

And in conclusion, we would like to note that the Japanese, who actively consume seafood in general and seaweed in particular, are distinguished by enviable health and high life expectancy.

Use of algae in folk medicine

Seaweed infusion recipe for treating the thyroid gland

To prepare this tincture you will need: two tablespoons of kelp, two hundred and fifty grams of water. You will need to grind the kelp into a fine powder and then consume it before bed with water for fifteen to thirty days.

Dry kelp recipe for treating stomach ulcers

To do this you will need two tablespoons of kelp, two hundred and fifty grams of water. The algae should be ground to a powder and taken one tablespoon with water three to four times a day before or after meals. The course of treatment will last from two weeks to one month.

Recipe for seaweed decoction for the treatment of varicose veins

You will need: one tablespoon of fucus or kelp, as well as two hundred and fifty ml of water. To prepare, pour boiled water over the seaweed at a temperature of 35-37 degrees Celsius. Then leave for several hours. The resulting mixture must be used as follows. Apply the tincture to a linen cloth, then wrap it around the problem areas of the body and cover with a towel. The initial procedure time is up to half an hour. Gradually increase the time to two hours. The wrap should be done 1-2 times a week. General course treatment - ten to fifteen procedures.

Recipe for treating herpes

You will need twenty-five drops of kelp alcohol extract. Grind 100 grams of seaweed, infuse in 100 grams of 96% alcohol for 7 days in a dark place. Soak cotton wool in the extract and apply it to the affected area. Use two to three times daily for cold sores.

Laminaria for the treatment of cervical erosion

All you need is two tablespoons of dry kelp, or fucus, two hundred and fifty ml of water. The algae should be finely chopped and taken one teaspoon with water once or twice a day. The course of treatment is only two weeks.

Attention! Anyone with kidney or thyroid problems should consult their doctor before adding seaweed to their diet on a regular basis.

Contraindications

  • Allergy to seafood, iodine.
  • Also, women are advised not to consume algae during pregnancy.

18. Division 9. Brown algae - Phaeophyta (Phaeophycophyta, Phaeophyceae) (N. A. Moshkova)

Brown algae are predominantly marine multicellular plants, very large, complexly divided, attached to the substrate. Currently, about 1,500 species of brown algae are known, belonging to 240 genera. In the fresh, mostly cold running waters of temperate latitudes, 5 species of brown algae have so far been discovered. Due to the small size of their thalli and rare occurrence, they remain a poorly studied group of plants both biologically and ecologically.

A common external feature of brown algae individuals is the yellowish-brown color of their thalli, due to the presence of a large number of yellow and brown pigments. Thalluses can be microscopic (several tens of micrometers) and gigantic (30-50 m; in some species of the genera Laminaria Lamour., Macrocystis Ag., Sargassum Ag.). The shape of the thalli is very diverse: thread-like, crust-like, sac-like, lamellar (solid or with breaks, outgrowths and numerous holes, smooth or with longitudinal folds and ribs), and also bush-like.

The thalli of brown algae of the order Ectocarpales are most simply organized. In primitive organisms (Bodanella Zimmerm.), the thallus is represented by single-row, randomly branching threads in one plane, tightly adjacent to the substrate. Species of the genus Ectocarpus Lyngb. have bushy thalli formed by single-row ascending abundantly branching threads, the base of which is creeping rhizoids (Fig. 18.1).

In some representatives of the order Chordariales, the ascending filaments are connected into bundles enclosed in mucus. In this case, a distinction is made between a single-axis type of thallus structure, in which one thread rises upward from the base, and other threads branching off from it, running next to it, and a multi-axial type of structure, when a bundle of single-row threads rises upward from the base. In highly organized brown algae (Laminaria, Fucus Tourn., Sargassum), the thalli are differentiated and resemble flowering plants. They have stem-, leaf- and root-like parts; some large representatives have air bubbles that hold the branches in a vertical position.

The growth of brown algae is intercalary or apical. In the most primitive forms, intercalary diffuse growth occurs; in more evolutionarily advanced algae, an intercalary growth zone is already outlined. It is usually located in the basal part of multicellular hairs and causes the trichothallic growth characteristic of brown algae.

Multicellular filamentous hairs are formed on the surface of single-row thalli of brown algae. At the same time, real and false hairs are distinguished. True hairs have an intercalary growth zone at the base, where cells divide frequently and therefore they are smaller, short-cylindrical or disc-shaped. False hairs do not have such a special growth zone and are a continuation of vegetative single-row filaments with highly elongated cells devoid of chloroplasts.

In the multirow thalli of brown algae, specialization of cells with the formation of tissues is observed - a parenchymatous type of body structure. In the simplest case, a cortex is distinguished from intensely colored cells containing a large number of chloroplasts and special vacuoles - physodes, and a core consisting of colorless, often larger cells of the same shape. In more complexly organized brown algae (Laminariaceae, Fucaceae), the crustal layer reaches considerable thickness and consists of intensely colored cells of different sizes and shapes (Fig. 18.2). The superficial four layers of the cortex are formed by small cells elongated towards the surface. These upper layers are called meristoderm - dividing integumentary tissue. They are able to actively divide and produce hairs and reproductive organs. True hairs are located on the surface of the meristoderm scatteredly or in bunches and are often immersed with their bases in special recesses - cryptostomes. Deeper under the meristoderm lies a cortex of larger colored cells. In the central colorless part of the thallus, two groups of cells can be distinguished. In the center there are loosely or densely arranged filaments with highly elongated cells - the pith; between the pith and the cortex there are large colorless cells - the intermediate layer. The core of brown algae serves not only for the transport of photosynthetic products, but also performs a mechanical function; it often contains thin threads with thick longitudinal sheaths. Representatives of the order Laminariales have the most complex anatomical structure, in which mucous canals with special secretory cells for transporting photosynthetic products - sieve tubes and tubular filaments - develop in the core.

Thalluses of brown algae are attached to the ground or other substrates and only sometimes, due to mechanical damage, break off and float freely. The organs of attachment are usually long outgrowths - rhizoids; in large forms they are massive and are short root-like outgrowths that cover the substrate like bird claws. In representatives of the order Fucales and some other algae, the attachment organ is a disc-shaped growth at the base of the thallus - a basal disc, flattened or conical, tightly adhering to the ground.

The branching of brown algae is monopodial. Lateral branches are alternate, scattered or opposite. When they quickly grow to the size of the main thread (mother cells), dichotomous branching occurs. Quite often, alternate and opposite branches are placed in the same plane and the algae acquire a peculiar feathery appearance. The correct placement of branches is often masked by secondary branches.

Among brown algae there are species with ephemeral, annual and perennial thalli. The lifespan of thalli is greatly influenced by environmental conditions. Perennial thalli of brown algae come in several types. In some algae, the thallus is perennial, only the shoots on which the reproductive organs developed (Fucales) die each year; in others (Laminariales), the trunk and attachment organs are perennial, the lamellar part is annual. In some tropical species of Sargassum algae, only the disc that serves to attach the thallus is perennial.

Cells of brown algae are mononuclear, spherical, ellipsoidal, barrel-shaped, mostly cylindrical, elongated-cylindrical or short-cylindrical, disc-shaped, sometimes polygonal or of uncertain outline. They are also varied in size. The nucleus is of the usual type for eukaryotes.

The cell membrane is two-layered. The inner layer is cellulose, but the cellulose of brown algae differs in its properties from the cellulose of flowering plants and is therefore sometimes called algulose. The outer layer of the shell is pectin, usually consisting of protein compounds of alginic acid and its salts. Thanks to this structure, the shell of brown algae can swell greatly, turning into a mucous mass of sometimes significant volume. In most browns, the basis of pectin is a gummy substance - algin (soluble sodium salt of alginic acid), in some - fucoidin.

The contents of neighboring brown algae cells are communicated through plasmodesmata. In cells with thick membranes (in large thalli) pores are clearly visible.

Brown algae cells have one large or several small vacuoles. In addition, there are physodes - very small vacuoles (up to 4 μm in diameter) filled with fucosan, a compound similar to tannin. In young cells the physodes are colorless, in old cells they are colored yellow or brown.

Chloroplasts are wall-shaped, mostly numerous, small, disc-shaped, less often ribbon-shaped or lamellar. However, as cells age, the shape of the chloroplasts may change and instead of narrow, ribbon-like curved ones, numerous disc-shaped chloroplasts may appear in the cells. Pyrenoids are present either in the chloroplasts of vegetative cells or only in the chloroplasts of gametes; in a number of species, pyrenoids are absent or rare.

Brown algae are distinguished by a unique complex set of pigments. Chlorophylls a, c (chlorophyll b is absent), β- and ε-carotenes, as well as several xanthophylls—fucoxanthin, violaxanthin, antheraxanthin, zeaxanthin, etc.—are found in chloroplasts. Of these, fucoxanthin is particularly specific, with an intense brown color. Different ratios of these pigments determine the color of brown algae from olive-yellowish to dark brown, almost black.

The products of brown algae assimilation are various carbohydrates soluble in cell sap - kelp (a polysaccharide), mannitol (a hexahydric alcohol that plays a significant role in metabolism), as well as oil.

Brown algae have asexual and sexual forms of reproduction. However, vegetative propagation by fragmentation of the thallus cannot be considered unconditional. It is observed only when the severed thalli end up in more or less protected places and continue the growing season there. At the same time, their lower, older parts die off and are destroyed, and the young branches develop into independent plants, which, however, are not attached to the ground. Such plants, floating or lying on the ground, never form organs of sexual or asexual reproduction.

Special buds for vegetative propagation are present only in species of the genus Sphacelaria Lyngb. (Fig. 18.3).

Asexual reproduction is carried out by motile zoospores, formed in large numbers in single-locular sporangia. In the most simply organized marine and freshwater brown algae (Ectocarpus, Sphacelaria, Pleurocladia A. Br., etc.), single-locular sporangia are spherical or ellipsoidal cells, which are located as lateral outgrowths of branches (Fig. 18.4, 1). In sporangia, reduction division of the nucleus occurs, followed by multiple mitotic divisions; Chloroplasts divide simultaneously with the nuclei. As a result, a large number of zoospores are formed, which are released through a rupture of the shell at the top of the sporangium and, after swimming for a short time, germinate into a new plant, the same in appearance, but already haploid. In species of the genus Laminaria, zoosporangia form sori on the surface of the leaf-shaped plate. The sorus consists of paraphyses and zoosporangia (see Fig. 18.4, 2, 5). Paraphyses are elongated cells, with chloroplasts at the upper extended end, developing on the surface of the thallus between the reproductive organs and serving to protect them. The shell of the paraphysis at the apex is strongly mucused, forming a kind of thick mucous cap. The mucous caps of adjacent paraphyses close together, resulting in a continuous thick layer of mucus that protects the sorus. Zoosporangia are elongated ellipsoid, with a mucous membrane at the apex. In zoosporangia, depending on the species, 16-128 zoospores develop. The first division of the nucleus is reduction. Some brown algae reproduce by immobile, flagellated spores - aplanospores. Monospores are observed only in species of the order Tilopteridales, tetraspores - in species of the order Dictyotales (Dictyota dichotoma (Huds.) Lamour., see Fig. 18.4, 4).

The sexual process is iso-, hetero- and oogamous. Gametes are usually produced in multilocular gametangia, one in each chamber. Motile cells of brown algae - zoospores into gametes - have a similar structure - they are pear-shaped, with one chloroplast and two flagella attached to the side. One flagellum is longer, feathery, directed forward, the other is shorter, smooth, whip-shaped, directed backward. Stigma in motile cells is not always noticeable. The chloroplast of male gametes during oogamy may be colorless.

In the development cycle of most brown algae of the class Phaeozoosporophyceae, there is a change in developmental forms and an alternation of sexual and asexual generations, i.e., gametophyte (sometimes also gametosporophyte, if the same organism can give rise to zoospores and gametes) and sporophyte.

These processes are described in detail in section 3.2.3. Here we will dwell only on some of the features of the development cycles of brown algae. In the most primitive marine brown algae of the order Ectocarpales, an isomorphic change in developmental forms is observed, but there is still no strict alternation of generations. From spores produced by a sporophyte, both gametophytes and sporophytes can develop.

Regular isomorphic changes in developmental forms are observed in representatives of the order Dictyotales. The most widespread of them is Dictyota dichotoma (Huds.) Lam., which has a forked thallus with flat branches, usually located in the same plane, without a longitudinal rib (Fig. 18.5).

Algae of the order Laminariales have a heteromorphic change in developmental forms with the obligatory alternation of sporophytes and gametophytes. Their development cycle is characterized by the correct replacement of a powerful sporophyte and a microscopic, simply arranged gametophyte.

Brown algae, which do not have a change in developmental forms, but only a change in nuclear phases, include representatives of the families Fucaceae, Cystoseiraceae and Sargassaceae. Their normal reproduction is possible only through sexual intercourse. The sexual process is typical oogamy. The reproductive organs develop in the conceptacles (Fig. 18.6). Long hairs grow from the wall of the conceptaculum - paraphyses, filling almost its entire cavity. Particularly long hairs develop in the female conceptacles, where they protrude in the form of a tuft from the opening of the conceptacle. Oogonia and antheridia develop among these hairs (Fig. 18.7, 1-5). Antheridia are formed in large numbers at the ends of special single-row branched branches growing from the wall of the conceptaculum. Two layers are distinguishable in their shell. When the antheridium matures, its outer shell bursts and the antherozoids come out in the form of a package surrounded by an inner shell. IN sea ​​water the inner shell ruptures and pear-shaped antherozoids with a large nucleus and an orange stigma are released. Oogonia are spherical or ellipsoidal, equipped with a three-layer shell, located in conceptacles on a short unicellular stalk. Eight eggs are formed in the oogonia; they are released into the water, surrounded by two inner layers of the oogonia shell. When the eggs are completely freed from the oogonia membranes, fertilization occurs. The fertilized egg produces its own thick shell and immediately begins to germinate, forming a new fucus thallus.

The development cycles of freshwater brown algae have not been studied.

There are some differences in views on the classification of brown algae. According to a number of researchers, the department Phaeophyta is divided into 2 classes: Phaeozoosporophyceae and Cyclosporophyceae. The cyclosporans include brown algae, in which the reproductive organs develop in conceptacles and are large in size, allowing them to be seen on preparations with the naked eye. Phaeozoosporans include all other brown algae, many of which reproduce by zoospores. Since the 1930s, there has been a tendency to classify brown algae depending on the characteristics of their development cycles. At the same time, it was proposed to divide brown algae into 3 classes: Isogenerate, Heterogenerate, Cyclosporae. The proposed classification has become very widespread. However, the division of brown algae into isogenerate and heterogenerate is rather arbitrary, since in both classes, in separate orders, there are representatives with the opposite type of change in development forms. Adhering to the views of domestic algologists, we accept the classification scheme for dividing brown algae into 2 classes - Phaeozoosporophyceae and Cyclosporophyceae.

The question of the origin of brown algae is still poorly understood. A. Sherfell associated their origin with golden ones (Chrysophyta). According to A. Pascher, there is a phylogenetic connection between brown and cryptophytes (Cryptophyta). The peculiar structure of the flagella, together with the brown coloration, allowed M. Chadefault to unite into one large department Chromophycophyta such large taxa as Pyrrhophyta (in which, in addition to peridines, he included cryptophyte and euglena algae), Chrysophyta (to which he included, in addition to golden ones, yellow-green and diatoms) algae) and Phaeophyta. In terms of biochemical properties, of all brown-colored organisms, diatoms are closest to brown algae. It is diatoms and brown algae that are characterized by such common pigments as chlorophyll (also characteristic of peridinea), fucoxanthin (also found in golden algae) and neofucoxanthins A and B. Taking into account the presence of a number of similarities between diatoms, golden and brown algae, we join thoughts expressed by a number of scientists about the possibility of their origin from close, if not common, monadic ancestors.

According to G. Papenfuss, the original order of brown algae is Ectocarpales. The parenchymatous structure of the thallus, apical growth, oogamous sexual process, and heteromorphic changes in developmental forms in different groups of brown algae developed independently of each other.

Marine brown algae are widespread in all seas of the globe. Their thickets are common in the coastal waters of Antarctica and the northern islands of the Canadian Arctic Archipelago. They reach their greatest development in the seas of temperate and subpolar latitudes, where, due to low temperatures and increased concentrations of nutrients, the most favorable conditions for their vegetation are created. Brown algae occupy vertically all horizons of the shelf. Their thickets are found from the littoral zone, where they are out of the water for hours at low tide, to a depth of 40-100 (200) m. And yet the most dense and extensive thickets of brown algae are formed in the upper part of the sublittoral zone to a depth of 6-15 m. In these places, with sufficient illumination, there is a constant movement of water caused by the surf and surface currents, which ensures, on the one hand, an intensive supply of nutrients to the thalli, and, on the other, limits the settlement of herbivorous animals.

Typically, brown algae live on rocky or stony soils, and only in calm places near the coast or at great depths can they be held on the valves of large mollusk shells or on gravel. The detached thalli are carried by the current to quiet places with a muddy or sandy bottom, where they continue to vegetate with sufficient light. Species with air bubbles on the thallus, when lifted off the ground, float to the surface of the water, forming large accumulations (Sargasso Sea). Among marine brown algae there are a significant number of epiphytic and endophytic forms.

In the seas of temperate and subpolar latitudes, brown algae reach their greatest development in the summer months, although the rapid growth of their thalli begins in early spring, when the water temperature approaches 0°C. In tropical seas, the massive development of brown fish is confined to the winter months, when the water temperature drops somewhat. Some types of marine brown algae can be found in highly desalinated areas of seas with salinity less than 5‰.

The role of brown algae in nature is extremely large. They are one of the main sources organic matter in the coastal zone, especially in the seas of temperate and subpolar latitudes, where their biomass can reach tens of kilograms per 1 m2. In addition, kelp beds provide breeding, shelter, and feeding habitat for many coastal animals; they also create conditions for the settlement of microscopic and macroscopic algae of other systematic groups.

Brown algae is also of great economic importance, especially as a raw material for the production of various substances (for example, alginates - salts of alginic acid, in particular sodium alginate). This substance is widely used to stabilize various solutions and suspensions. Adding a small amount of sodium alginate improves the quality of food products (canned food, ice cream, fruit juices, etc.), various coloring and adhesive substances. Alginates are used in book printing, in the production of plastics, synthetic fibers and plasticizers, for the production of weather-resistant paint and varnish coatings and building materials. They are found in high-quality machine lubricants, soluble surgical sutures, ointments and pastes in the pharmaceutical and perfume industries. In foundry production, alginates are used to improve the quality of molding earth. Alginates are used in the production of electrodes for electric welding, which make it possible to obtain higher-quality seams. Brown algae is also used as a raw material for the production of mannitol, used in the pharmaceutical industry, in the food industry - for the production of diabetic foods, and in the chemical industry - in the production of synthetic resins, paints, paper, explosives, and leather tanning. Brown algae contains a large amount of iodine and other trace elements, so they are used to prepare feed meal. In fresh and processed form, they are used as fertilizers.

Brown algae has long been used in medicine. Now new directions for their use are being identified, for example, for the production of blood substitutes, for the production of drugs that prevent blood clotting and promote the removal of radioactive substances from the body. Since ancient times, brown algae (mainly representatives of the order Laminariales) have been consumed by humans as food.

The negative properties of brown algae include their participation, together with other organisms, in the fouling of ships, buoys, as well as various hydraulic structures immersed in water, which worsens their performance.

Intensive use of wild marine macrophytes, in particular brown algae, has led to the depletion of their natural reserves and has confronted humanity with the need for their artificial cultivation. Therefore, in the last 30 years, algae aquaculture has developed significantly. In Norway and Great Britain, they not only successfully cultivate species of the genus Laminaria, but also improve the technology for their production. In France, work is being done to acclimatize representatives of the genus Macrocystis. Seaweed aquaculture is rapidly developing in the United States. In this case, special attention is paid to Macrocystis pyrifera. In the USSR, research is being carried out on artificial breeding of Laminaria saccharina (L.) Lam. in the White Sea. Thus, the cultivation of seaweed is acquiring an industrial character and is becoming an increasingly profitable branch of crop production, despite some economic and environmental difficulties.

In fresh waters of temperate latitudes, 5 species of brown algae from the class Phaeozoosporophyceae were found: Bodanella lauterbornii Zimmerm. (order Ectocarpales, family Ectocarpaceae) (Fig. 18.8, 1), Pleurocladia lacustris A. Br. (order Chordariales, family Myrionemataceae) (Fig. 18.8, 2). Heribaudiella fluviatilis (Aresch.) Sved. (order Chordariales, family Lithodermataceae (Fig. 18.8, 3)), Streblonema longiseta Arnoldi (order Chordariales, family Streblonemataceae) (Fig. 18.8, 4). Sphacelaria fluviatilis Jao (order Sphacelariales, family Sphacelariaceae) (Fig. 18.8, 5).

Orders
  • Ascozeiraceae ( Ascoseirales)
  • Chordariaceae ( Chordariales)
  • Cutleriaceae ( Cutleriales)
  • Dictyosiphonaceae ( Dictyosiphonales)
  • Desmarestiaceae ( Desmarestiales)
  • Dictyotaceae ( Dictyotales)
  • Chordariaceae ( Chordariales)
  • (Discosporangiales)
  • Ectocarpaceae ( Ectocarpales)
  • Fucus ( Fucales)
  • (Ishigeales)
  • Laminariaceae ( Laminariales)
  • (Nemodermatales)
  • (Onslowiales)
  • (Ralfsiales)
  • Scytosiphonaceae ( Scytosiphonales)
  • (Scytothamnales)
  • Sphacelariaceae ( Sphacelariales)
  • Sporochnovae ( Sporochnales)
  • Tylopteridae ( Tilopteridales)
  • (Syringodermatales)

Taxonomy
on Wikispecies
Images
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ITIS
NCBI
EOL

The thalli of kelp and fucus are the most complex. Their thalli show signs of tissue differentiation with cell specialization. In their thallus one can distinguish: a cortex, consisting of several layers of intensely colored cells; core, consisting of colorless cells, often collected in threads. In kelp, sieve tubes and tubular threads are formed in the core. The core performs not only a transport function, but also a mechanical one, since it contains threads with thick longitudinal walls. Between the bark and the core of many brown algae there may be an intermediate layer of large colorless cells.

The growth of the thallus in brown algae is most often intercalary and apical, less often basal. Intercalary growth may be diffuse or there may be a growth zone. In large representatives, the intercalary meristem is located at the transition point of the “petiole” to the “leaf blade”. Large algae also have a meristematic zone on the surface of the thallus, the so-called meristoderm (a kind of analogue of the cambium of higher plants).

An unusual type of meristem, found only in some brown algae, is the trichothallic meristem, whose cells develop at the base of the true hairs. True hairs are located on the surface of the meristoderm scatteredly or in bunches and are often immersed at their base in special recesses - cryptosomes.

Flagella

The flagellar stages in the life cycle of brown algae are represented only by gametes and zoospores. Two unequal flagella attached to the side (sperm Dictyota have only one flagellum). Typically, the long feathery flagellum in brown algae is directed forward, and the smooth one - sideways and backwards, but in the spermatozoa of Laminariaceae, Sporochnaliaceae and Desmarestiaceae, on the contrary, the long feathery flagellum is directed backwards, and the short smooth one - forwards. In addition to the tripartite mastigonemes, the long flagellum contains scales and spines; its tip can be spirally twisted. At the base of the smooth flagellum there is a basal swelling. Fucus spermatozoa have a peculiar funnel-shaped structure around the flagellum - the proboscis, supported by microtubules of the first root.

The basal bodies of the flagella are located at an angle of almost 110 degrees and are connected by three striated ribbons. The typical configuration for brown algae is the presence of four microtubular roots. One root consists of 7-5 microtubules, directed towards the anterior end of the cell, where it bends and goes backward; the other root consists of 5-4 microtubules and is directed in two directions from the basal body - towards the anterior and posterior ends of the cell; two more roots are short, each consisting of one microtubule. There is no rhizoplast in the radicular system. In a number of brown algae, the structure of the root system differs from that described.

Veils

Soluble alginates are part of the cell wall matrix, sometimes accounting for up to 40% of the dry weight of the thallus.

Fucans (fucoidans or ascophyllans) are polymers of L-fucose and sulfated sugars. Their function is not fully understood. They are believed to play an important role in zygote attachment and germination in fucus algae.

In some dictyotes, for example Padina, lime is deposited in the cell walls in the form of aragonite.

Cellular structures

Brown algae cells contain from one to many plastids. Most often, chloroplasts are small, disc-shaped, parietal. Their shape can be stellate, ribbon-like or lamellar; The shape of chloroplasts can change as the cell ages. The chloroplast shell consists of four membranes; where the chloroplast is located next to the nucleus, the outer membrane of the chloroplast endoplasmic reticulum merges into the outer membrane of the nucleus. The periplastid space is well developed. The lamellae are trithylakoid; there is a surrounding lamella; chloroplast DNA is assembled into a ring.

Only 8 species belonging to the genera are found in fresh waters Heribaudiella, Ectocarpus, Sphacelaria, Pseudobodanella, Lithoderma, Pleurocladia And Porterinema. Maybe, H. fluviatilis- a common component of river flora, but due to ignorance of this group it often goes unnoticed in samples.

The role of brown algae in nature is extremely great. This is one of the main sources of organic matter in the coastal zone, especially in the seas of temperate and subpolar latitudes; their thickets serve as a feeding, sheltering and breeding place for many animals.

Brown algae is used as food, livestock feed, fertilizer, and for the production of alginates and mannitol. Annual fee Laminaria and related algae reaches 2 million tons of wet weight; more than a million tons are produced by its mariculture in China.

Alginates are non-toxic compounds with colloidal properties, so they are widely used in the food and pharmaceutical industries. Alginic acid and its salts are capable of 200-300-fold absorption of water, forming gels that are characterized by high acid resistance. In the food industry they are used as emulsifiers, stabilizers, gelling and moisture-retaining components. For example, dry powder sodium alginate is used in the production of powdered and briquetted soluble products (coffee, tea, milk powder, jelly, etc.) for their rapid dissolution. Aqueous solutions of alginates are used for freezing meat and fish products. Around the world, about 30% of the alginates produced go to the food industry.

In the textile and pulp and paper industries, alginates are used to thicken paints and enhance the strength of their bond to the base. Impregnation of fabrics with some salts of alginic acid makes them waterproof, acid-resistant and increases mechanical strength. A number of salts of alginic acids are used to produce artificial silk. During World War II, a large amount of camouflage fabric and nets for residential and industrial buildings was produced from alginic acid and its salts in the USA and England. Alginates are used in metallurgy as a component of molding earth, in radio electronics - as a binding agent in the manufacture of high-quality ferrites, as well as in mining, chemical and other industries.

In the pharmaceutical industry, alginates are used to coat tablets, pills, as component bases for various ointments and pastes, and as gel carriers for drugs. In medicine, calcium alginate is used as a hemostatic agent and as a sorbent that promotes the removal of radionuclides (including strontium).

In North America, alginates are collected Macrocystis And Nereocystis, on the European coast species are used Laminaria And Ascophyllum. By the end of the twentieth century, the annual production of alginates in the world reached 21,500 tons: 12,800 tons in Europe, 6,700 in North America, 1,900 in Japan and Korea, 100 in Latin America. In Russia in 1990, only 32 tons of food-grade sodium alginate were produced.

Fucoidans are effective anticoagulants, even more active than heparin. Their use for the production of antitumor drugs and antiviral compounds is considered promising. Even in very low concentrations they can inhibit the attachment of viruses to the surface of cells. Fucoidans are capable of forming extremely strong and viscous mucilages, which is used in the production of stable emulsions and suspensions.

Mannitol is used as a sugar substitute for diabetics. In addition, it can be used as a plasma substitute for blood conservation.

The cells of many brown algae accumulate iodine. Its content can reach 0.03% -0.3% of the fresh mass of algae, while its content in sea water reaches only 0.000005% (0.05 mg per liter of water). Until the 40s. XX century brown algae were used to extract iodine.

The energy crisis that has engulfed last years many countries of the world, has led to the need to search for new non-traditional energy sources. So, in the USA, the possibility of growing algae is being studied for this purpose. Macrocystis pyrifera with subsequent processing into methane. It is estimated that from an area of ​​400 square kilometers occupied by this algae, 620 million cubic meters of methane can be obtained.

In recent years, brown algae have attracted attention due to their ability to release organic bromides (bromoform, dibromochloromethane and dibromomethane) into the atmosphere. The annual release of organic bromides by algae reaches 10,000 tons, which is comparable to the formation of these substances by industry. There is an opinion about the connection between the release of organic bromides and the destruction of ozone in the Arctic atmosphere.

Phylogeny

Fossil finds that may be related to brown algae date back to the Late Ordovician (about 450 million years) and are known as Winnipegia And Tallocystis from the Middle Silurian (425 Ma). But these findings cannot be accurately attributed only to brown algae, since they are also similar to some modern green and red algae. Fossil finds that can definitely be associated with modern brown algae date back to the Miocene (5-25 million years). This Zonarites And Limnophycus, reminiscent of modern Dictyota etc. Molecular methods determine the age of brown algae as 155-200 million years.

Browns are a monophyletic group, but the relationships within it are not fully understood. To date, data on the analysis of nucleotide sequences of a number of genes, due to their small number, do not yet reflect the complete picture in the phylogeny of brown algae. Traditionally, the most primitive brown algae included ectocarpus, but gene sequence analysis rbc L, psa A, psa B and their combinations shows that they are not. In the trees obtained in these studies, Ectocarpus are located at the top, and representatives of the order are located at the base Ishigeales, which separated early from the general tree of brown algae.

There is no doubt that brown algae are classified as ochrophytes. Within this department, for a number of features, they have long been considered the closest to golden algae. This view is currently disputed. In terms of ultrastructural, biochemical features and comparison of nucleotide sequences of the 16S rRNA gene, brown algae are closest to tribophyceae. Since the description of the new class Schizocladiophyceae, a number of studies have shown that it is the sister group to brown algae.

Variety and classification

The class contains about 265 genera and 1500-2000 species. The type of organization of the thallus, the presence or absence of a pyrenoid, the method of growth, the type of sexual reproduction (isogamy, heterogamy, oogamy) and life cycle are used to distinguish the orders of brown algae. In recent years, in connection with the use of data on comparison of nucleotide sequences of a number of genes, the system of brown algae has been actively revised. IN different systems 7 or more orders are distinguished, with different understandings of the volume of the orders Ectocarpales and Fucales. In 1999, F.Rousseau and B.Reviers proposed a broad concept of the order Ectocarpales s.l., which included the orders Chordariales, Dictyosiphonales, Punctariales, Scytosiphonales. At the same time, Ralfsiales and 2004 Ischigeales were excluded from it (this order was described for the genus Ischige, previously classified as a member of the Chordariaceae family). In one order Fucales s.l. it was proposed to combine the orders Fucales and Durvillaeales. In 1998, a new order of brown algae, Scytothamnales, was described based on the characteristics of plastids (centrally located stellate cells with a pyrenoid) and SSU rDNA data. This new order includes three types: Scytothamnus, Splachnidium(derived from dictyosiphonaceae) and Stereocladon(derived from Chordariaceae).

Ecological group and living conditions

The department of brown algae (Phaeophyta) has about 1,500 species.

Brown algae live almost only in the seas(only a few species are found in fresh water bodies). Habitat depth is relatively shallow, for most species - 5-15 m, but some species are distributed to a depth of 40-100 m and even 200 m. Brown algae are included in ecological group of benthic(bottom) organisms.

The structure of brown algae

The precursors of brown algae chloroplasts are bacteria close to Heliobacterium chlorum. The main photosynthetic pigment is chlorophyll a, auxiliary pigments are carotenoids, including brown fucoxanthin and yellow xanthophylls. Auxiliary pigments of brown algae expand the spectrum of light they absorb in the blue-green region.

Spare substance - soluble carbohydrate similar to starch kelp.

The thallus (thallus) is only multicellular. Large, sometimes multi-meter thalli of brown algae are kept afloat thanks to air bubbles located in the thallus. Many representatives of brown algae show tissue differentiation. Inside the thallus they pass vascular bundles, reminiscent of the phloem of higher plants. The appearance of the vascular system is associated with the need to transport nutrients through the multi-meter thallus - from the upper, photosynthetic, parts of the plant to the lower ones, where conditions for photosynthesis are worse.

Rice. The structure of brown algae

Reproduction

In brown algae, the forms of sexual reproduction are isogamy, heterogamy and oogamy. There is an alternation of generations, usually heteromorphic. Asexual reproduction - zoospores and pieces of thallus (vegetative reproduction).

The meaning of brown algae

Brown algae form entire “underwater forests” at relatively shallow depths, surrounding with a continuous wall the coasts of all seas and oceans of both hemispheres. These "underwater forests" provide food, shelter and breeding grounds for a huge number of sea ​​creatures, including for many commercial fish. After the algae die, they form detritus, which is food for planktonic organisms.

Brown algae are widespread, but the largest species are found in the seas of temperate and northern latitudes.

Rice. 1. Brown algae: a) macrocystis (Macrocystus); c) sargassum; c) fucus (Fucus); d) kelp (Laminaria)

Typical representatives of the department

Brown algae is widespread in the Far Eastern seas kelp (seaweed), The length of the thallus is 5-6 m. Sea kale is used as food by the peoples of Southeast Asia.

On the Pacific Coast South America giant brown algae found macrocystis. Its huge thallus reaches a length of 50-60 m. Interestingly, it grows in just one season.

In the littoral zone (the part of the bottom exposed at low tide) of the northern seas, extensive thickets are formed by fucus(thallus length up to 2 m).

The South Atlantic (Sargasso Sea) is characterized by huge accumulations of brown algae Sargassum."Sargasso" means "grape" in Spanish, and indeed the groups air bubbles The thallus of these algae that keep them afloat resemble bunches of grapes. The Sargassum species found in the Sargasso Sea are the only brown algae that float on the surface of the water rather than being attached to the bottom.

Economic importance

Brown algae cells are covered on top of a cellulose shell with a layer of a special carbohydrate - pectin, consisting of alginic acid or its salts (alginates). When mixed with water (in a ratio of 1:300), alginates form a viscous solution.

Alginates are used extremely widely:

  • in the food industry (when producing marmalades, juices, marshmallows, etc.);
  • in perfumery (production of creams, pastes, gels, etc.);
  • in medicine and the pharmaceutical industry (in the manufacture of ointments, pastes, soluble surgical threads);
  • in the chemical industry (in the production of varnishes, paints, adhesives that do not lose their qualities when freezing and thawing; plastics, plasticizers, synthetic fibers);
  • in book printing (to improve print quality);
  • alginates make natural fabrics non-fading and waterproof; they are used to improve the quality of molding soil in foundry, for the manufacture of electrodes (improving the quality of welds) and in many other sectors of the national economy.

Hexahydric alcohol is obtained from brown algae mannitol, used as a blood substitute, as a medicine in the treatment of diabetes, as well as in the light and chemical industries (in the production of paper, varnishes, paints, explosives and for leather dressing).

Brown algae kelp (sea kale) is consumed for food.

Brown algae is used and how medicine: as a mild laxative, in the treatment of vascular diseases, and also as a source of iodine and trace elements for diseases of the thyroid gland. Iodine was first obtained from brown algae, and in the past they were the main raw material for its production. Currently, the scale of this production has sharply decreased due to the emergence of more cost-effective sources of iodine.

Brown algae can be used as gold deposit indicators, since they are able to accumulate it in the cells of the thallus.

Brown algae is also used in agriculture - as fertilizers And for livestock feed.