The study of algae in aquarium conditions. Consider some examples of algae

Multicellular green algae

Examples of multicellular green algae are ulotrix and spirogyra. . Kinds genus, aulotriks They live mainly in fresh, less often in marine and brackish water bodies, as well as in the soil. Algae attach themselves to underwater objects, forming bright green bushes up to 10 cm in size or more.

Unbranched ulotrix filaments, consisting of one row of cylindrical cells with thick cellulose membranes, are attached to the substrate by a colorless conical basal cell that acts as a rhizoid. Characteristic is the structure of the chromatophore, which has the form of a parietal plate, forming an open belt or ring (cylinder). All cells, except for the basal one, are able to divide, causing a continuous growth of the thallus.

Asexual reproduction is carried out in two ways: by breaking up the thread into short sections, each of which develops into a new thread, or by the formation of four flagellar zoospores in the cells. They emerge from the mother cell, shed flagella one by one, attach sideways to the substrate, are covered with a thin cellulose membrane and germinate into a new thread.

Reproduction of filamentous algae ulotrix: red arrows - asexual reproduction, blue arrows - sexual reproduction.

The sexual process is isogamous. After fertilization, the zygote first swims, then settles to the bottom, loses flagella, develops a dense membrane and a mucous stalk, which is attached to the substrate. This is a resting sporophyte. After a dormant period, the reduction division of the nucleus occurs and the zygote germinates with zoospores.

Thus, in life cycle ulothrix, there is an alternation of generations, or a change in sexual and asexual forms of development: a filamentous multicellular gametophyte (the generation that forms gametes) is replaced by a unicellular sporophyte - a generation that is represented by a kind of zygote on a stem and is able to form spores.

Spirogyra common in stagnant and slowly flowing waters, where it often forms large masses of "mud" of bright green color. It is a thin thread consisting of long cylindrical cells arranged in one row with a clearly visible cell wall. Outside, the threads are covered with a mucous membrane.

Spirogyra filamentous alga cell

A characteristic feature of spirogyra is a ribbon-like, spirally curved chromatophore located in the wall layer of the cytoplasm. In the center of the cell is the nucleus, enclosed in a cytoplasmic sac and suspended on cytoplasmic strands in a large vacuole.

Asexual reproduction is carried out by breaking the thread into short sections, while there is no sporulation. The sexual process is conjugation. In this case, two threads are usually located parallel to each other and grow together with the help of copulatory outgrowths or bridges. Their shells dissolve at the point of contact, and a through channel is formed, through which the compressed contents of the cell of one thread moves into the cell of another and merges with its protoplast. The zygote formed as a result of fertilization germinates after a dormant period. This is preceded by a reduction division of the nucleus: out of the four nuclei formed, three die off, and one remains the nucleus of a single seedling that emerges through a rupture in the outer layers of the zygote shell.

Spirogyra
(Spirogyra)

Spirogyra(Spirogyra Link.) - a green alga from the conjugate group (see Conjugatae), belongs to the Zygnemeae family. The body of Spirogyra is a non-branching thread, it consists of cylindrical cells. In the latter there is a chromatophore characteristic of Spirogyra (see): one or more spirally curled, green ribbons. Colorless bodies are placed in the chromatophores, around which starch grains, the so-called pyrenoids, are grouped. Very well visible in the microscope, the nucleus, suspended on protoplasmic filaments, is located in the middle of the cell. Spirogyra grows by intercalary (uniform) cell division. The sexual process of Spirogyra is copulation or conjugation: the cells of 2 adjacent filaments are interconnected by lateral outgrowths; the membranes separating these outgrowths are destroyed and, thus, a copulatory canal is obtained, through which the entire contents of one cell (male) passes into another (female) and merges with the contents of the latter; the cell in which the fusion has taken place (zygote) rounds off, separates from the filament and, dressing in a thick shell, turns into a zygospore. The zygospore overwinters and germinates into a young thread in spring. In the zygote, after the contents of the male and female cells merge, the chromatophore of the first cell dies and only the second remains, the nuclei first merge into one, which is then divided into 4 unequal in size (unequal division of the nucleus); of these, 2 smaller ones blur in the surrounding plasma, and 2 large ones, merging, form the nucleus of the zygote.

The described copulation between cells of different threads (dioecious) is called ladder. In the case when a channel is formed between two adjacent cells of the same thread, copulation (single-house) is called lateral. In most Spirogyra, during the sexual process, the copulatory canal is always developed (subgenus Euspirogyra) and male and female cells are the same, in some, these cells are unequal in size, and the copulatory canal is very weakly developed or completely absent, so that the cells merge with each other directly ( subgenus Sirogonium). Due to the size of Spirogyra cells, reaching up to 0.01 mm in some of its species, due to the clarity of their structure, this algae is one of the best studied and serves as a classic object in the study of the anatomy of the cell and nucleus.

Green algae spirogyra

Spirogyra is one of the most common green algae in fresh waters of all parts of the world, and is also found in brackish waters. Its threads are collected in large green clusters that float on the surface of the water or creep along the bottom and are very often found in the mud of stagnant and flowing waters, in ponds, swamps, ditches, rivers, streams, pools, etc.

Spirogyra under the microscope

In total, up to 70 species of Spirogyra are known, differing from each other in the shape and size of cells and zygospores, as well as the shape and number of chromatophore ribbons in them, and belonging, as mentioned above, to the 2nd departments - Euspirogyra (the most common: Sp. tenuissima Hass., longata Kg. with one ribbon, Sp. nitida Kg. with several ribbons, Sp. grassa Kg. with very thick cells, etc.) and Sirogonium (Sp. stictica Sm., etc.). For Russia, up to 40 types of Spirogyra are indicated

Ulotrix

Ulotrix(lat. Ulothrix) - a genus of green algae Chlorophyta .

Inhabits marine and fresh waters, forming green mud on underwater objects. Filamentous type of thallus differentiation. The chloroplast is parietal in the form of a girdle, closed or open, with several pyrenoids. The core is one, but it is not visible without painting.

Order ulotrix (Ulotrichales)

The thallus of the ulotrix is ​​built according to the type of a single-row unbranched thread. It is composed of cells similar to each other in structure and function (Table 30, 2). Potentially, all cells are capable of dividing and participating in the growth of a plant, just as all cells can form spores and gametes. Only the cell at the base of the thread differs from the rest: with its help, the thallus is attached to the substrate (in attached forms). Ulothrix cells have considerable autonomy. This property is associated with the ability to regenerate and vegetative reproduction - individual cells or sections of filaments easily break away from the filaments and proceed to independent growth.

The order includes more than 16 genera. Despite the fact that all their representatives are built as a simple single-row thread, important differences can be found in their organization, on the basis of which the whole order is divided into three groups. In algae of the first group, the thread is a series of cells loosely located in a thick mucous membrane. For example, algae genus geminella geminella. It is interesting that all ulotrix with a similar structure are planktonic organisms.

The second group includes those filamentous algae that vegetate as single cells or as short chains of 2-4 cells very loosely connected to each other. Threads are formed rarely and on a short time. An example of such a structure is genus Stichococcus(Stichococcus, Fig. 216, 2). The algae included in this group lead a terrestrial lifestyle.

The central group of the order is the third group, which includes algae, built like a typical multicellular filament, in which the cells are tightly connected to each other without the help of a mucous sheath. The algae belonging to this group are overwhelmingly attached organisms, at least when young. Their threads are more permanent formations, they no longer break up so easily, and one can distinguish between the basal and apical parts in them. This includes several genera, including the central genus of the order - ulotrix(Ulothrix).

Ulothrix species (at present, more than 25 of them are known) live mainly in fresh water bodies, and only a very few enter brackish and marine waters. These algae can also settle on wet surfaces periodically wetted by splashes of surf or waterfalls.

One of the most widespread and well-studied species - ulothrix girdled(Ulothrix zonata).

The thallus of ulotrix consists of unbranched filaments of indeterminate length, which are attached to the substrate by a basal cell at the beginning of growth. Filament cells are cylindrical or slightly barrel-shaped, often short. Cell walls are usually thin, but often they thicken and may become stratified. Ulothrix cells, like cells of all algae of this order, contain a single parietal chloroplast with one or more pyrenoids and one nucleus located along the longitudinal axis of the cell. The chloroplast has the shape of a girdle that encircles the entire protoplast or only part of it.

Vegetative reproduction ulotrix is ​​carried out by fragmentation: the threads break up into short segments and each segment develops into a new thread. However, in this way, ulotrix does not reproduce as often as other algae of the order, which have a loose filament structure.

For asexual reproduction, zoospores are used, which are formed in all cells of the filaments, except for the basal one. The development of zoospores, as well as gametes, begins at the top of the thread and gradually captures the underlying cells.

Zoospores are ovoid cells with four flagella at the anterior end. They contain a stigma, several contractile vacuoles, and a parietal chloroplast. Ulothrix girdled has two types of zoospores - macrozoospores and microzoospores. Large macrozoospores have a broadly ovoid shape, often with a pointed posterior end, and a stigma located at the anterior end (. Microzoospores are smaller in size, have a rounded posterior end, and the stigma is located in the middle of the spore. The nature of microzoospores remains not yet entirely clear. Apparently, they represent is a transitional type between macrozoospores and gametes.

Quite often, zoospores do not leave the sporangium, but secrete a thin shell and turn into aplanospores. The latter are released as a result of the destruction of the thread, but sometimes they can begin to germinate while in the sporangium.

During sexual reproduction, gametes are formed in threads in exactly the same way as zoospores. As a rule, they develop in the same threads as zoospores, or in similar ones. Most often, the transition to sexual reproduction is associated with the end of active growth and the onset of adverse conditions. Unlike zoospores, gametes have two flagella. The sexual process is isogamous. Fusion occurs between gametes of the same or different filaments. The zygote remains mobile for a short time, then settles, loses flagella, dresses with a thick membrane and turns into a unicellular sporophyte. It falls into a period of rest, during which the accumulation of reserve substances occurs. The shape of the sporophyte is varied, usually it is spherical with a smooth shell, in some marine species becomes ovoid and sits on a mucous leg.

BROWN ALGAE,

brown algae(Phaeophyta), a type of spore plants, including 240 genera (1500 species), of which 3 are freshwater, the rest are marine. Thallus from olive green to dark brown due to the presence of a special brown pigment in the chromatophores fucoxanthin (C40H56O6), which masks other pigments (chlorophyll a, chlorophyll c, xanthophyll and beta-carotene). Brown algae are diverse in shape and size (from microscopic branched filaments to 40-meter plants). In higher brown algae (for example, kelp algae), tissue differentiation and the appearance of conductive elements are observed. Brown algae are characterized by multicellular hairs with a basal growth zone, which are absent in other algae. Cell membranes contain cellulose and specific substances - algin and fucoidin. Usually there is one nucleus in each cell. Chromatophores are mostly small, discoid. Some species of brown algae have pyrenoids that bear little resemblance to the pyrenoids of other algae. In the cell around the nucleus, colorless vesicles accumulate with fucosan, which has many of the properties of tannin. As reserve products, mannitol (polyhydric alcohol) and laminarin (polysaccharide), less often oil, accumulate in the tissues of brown algae. Brown algae reproduce sexually and asexually, rarely vegetatively. Typically, brown algae have a sporophyte and a gametophyte; in the higher ones (laminaria, desmarestia, etc.) they strictly alternate; in cyclospores, gametophytes develop on sporophytes; in primitives (ectocarp, chordaria, cutleria, etc.), the gametophyte or sporophyte may drop out of the development cycle or appear every few generations. Reproductive organs - single-celled or multi-celled sporangia. The multilocular sporangium, which more often functions as a gametangium, develops as a single cell or series of cells dividing by septa into chambers containing one gamete or spore inside. Meiosis usually occurs in unilocular sporangia; in dictyotes, in tetrasporangia. The sexual process is isogamy, heterogamy or oogamy. Pear-shaped spores and gametes, usually with an eye, have two flagella on the side, one directed forward, the other backward. brown algae are divided into 3 classes: Aplanosporophyceae (only dictyotes), Phaeosporophyceae (heterogenerate and isogenerate, with the exception of dictyotes) and Cyclosporophyceae (cyclosporophyceae). brown algae are common in all seas, especially in cold ones, where they form large thickets. They are used to obtain alginic acids and their salts - alginates, as well as feed flour and a powder used in medicine containing iodine and other trace elements. Some brown algae are used for food.

Brown algae: 1 - kelp; 2 - dictyota; 3 - ectocarpus; 4 - lessonia; 5 - neocystis; 6 - alaria; 7 - cystoseira; 8 - elachist bushes on the stem of another algae; 9 - fucus; 10 - dictyosiphon; 11 - Sargassum (all except 3 and 8 are greatly reduced; 3 - view under a microscope, enlarged approximately 40 times).

In multicellular representatives of green algae, the body ( thallus) has the form of filaments or flat leaf-shaped formations.

In flowing waters, you can often see bright green clusters of silky threads attached to underwater rocks and snags. This is a multicellular filamentous green alga ulotrix. Its threads consist of a number of short cells. In the cytoplasm of each of them are located core and chromatophore in the form of an open ring. The cells divide and the thread grows.

Also, filamentous multicellular green algae are widespread in ponds and lakes. spirogyra . Together with other filamentous algae, spirogyra forms large accumulations of mud. Silky, slimy to the touch, the thinnest threads of mud are separate plants of spirogyra. The filament of spirogyra consists of many cells arranged in one row.

The structure of spirogyra can be seen under a microscope. Spirogyra cells are large. The cytoplasm in them is located along the membrane. The middle of each cell is occupied by vacuoles with cell sap. In the cytoplasm is a chromatophore in the form of a green spiral ribbon. In the center of the cell is a rounded nucleus, as if suspended on threads extending from the cytoplasm. Therefore, it seems that the nucleus has a stellate shape.

Spirogyra feeds in the same way as Chlamydomonas. In the chromatophores of spirogyra, organic matter, starch, is formed from carbon dioxide and water.

Many multicellular algae, like Chlamydomonas, reproduce asexually and sexually.

Reproduction of the filamentous alga ulotrix: red arrows - asexual reproduction, blue arrows - sexual reproduction

It is more convenient to observe the reproduction of algae in another filamentous multicellular algae, which is called ulotrix. On pitfalls and snags in flowing waters, you can often see bright green tufts of silky threads. This is ulotrix. Ulothrix reproduces asexually and sexually, just like many other algae.

During asexual reproduction, the contents of some cells of this filamentous algae are compressed into lumps. Lumps slip into the water through the holes formed in the cell membrane. They develop four flagella, allowing small cells - zoospores - to swim freely in the water. They are called zoospores because these cells are motile.

Spirogyra filamentous alga cell

Zoospores of ulotrix in structure and shape resemble unicellular chlamydomonas; soon zoospores settle on some underwater object. After that, each cell begins to divide and gradually turns into a multicellular filamentous algae.

In water, small mobile cells formed in different filaments of algae merge in pairs and turn into one cell with a thick shell, called a spore.

After a dormant period, the spore begins to divide. Several cells are formed, each of which develops into an adult algae. In asexual reproduction, algal cells divide to form zoospores. Each zoospore then develops into an adult algae.

Multicellular green algae also live in the waters of the seas and oceans. An example of such algae is ulva, or sea ​​salad, about 30 cm long and only two cells thick.

The most complex structure in this group of plants is charophytes living in freshwater reservoirs. These numerous green algae appearance resemble horsetails. Chara alga nitella, or flexible glitter are often grown in aquariums.

The value of green algae in nature is great. Forming organic substances in its body, green algae absorb carbon dioxide from the water and, like all green plants, release oxygen, which is breathed by living organisms that live in the water. In addition, green algae, especially unicellular and multicellular filamentous algae, serve as food for fish and other animals.

brown algae

Brown algae are multicellular, mainly marine, plants with a yellowish-brown color of the thalli.

Their length ranges from microscopic to gigantic (several tens of meters). Thallus of these algae can be filamentous, spherical, lamellar, bushy. Sometimes they contain air bubbles that keep the plant upright in the water. Brown algae attach themselves to the ground rhizoids or disc-like overgrown base of the thallus.

In our Far Eastern seas and the seas of the Arctic Ocean, large brown algae kelp, or seaweed, grows. V coastal strip The Black Sea is often found brown algae cystoseira.

red algae

red algae, or crimson, - mostly multicellular sea ​​plants. Only a few species of crimson are found in fresh water. Crimson sizes usually range from a few centimeters to a meter in length (but there are also microscopic forms).

In form, red algae are very diverse and bizarre: filamentous, cylindrical, lamellar and coral-like, dissected and branched to varying degrees. They usually attach themselves to rocks, boulders, man-made structures, and sometimes other algae.

Due to the fact that red pigments are able to capture even a very small amount of light, purples can grow at considerable depths. They can be found even at a depth of 100-200 m.

Phyllophora, porphyry, etc. are widespread in the seas of our country.

In the treatment of algae, brown marine varieties, for example, kelp, ascophilium, amfeltia, fucus, containing the largest number alginic acid. Many doctors insist on the benefits of algae in the treatment of cancer and diseases of the endocrine glands. Algae have also been used in cosmetology.

What is seaweed and how are they useful to humans

Algae are a group of predominantly aquatic unicellular or colonial photosynthetic organisms. Unlike higher plants, algae do not have stems, leaves, or roots; they form a protoplast. They contain a wide range of useful substances.

The benefits of algae are known firsthand to adherents of alternative medicine. In particular, crushed or micronized algae are used in thalassotherapy: energy-rich substances penetrate the skin from the gruel, revitalizing metabolic processes and counteracting cellulite. In addition, the benefits of algae for humans is that they are rich in antioxidants: P-carotene, vitamins C and E, the superoxide dismutase enzyme, microelements and are a source of essential fatty acids.

In total, there are more than 30 thousand species of seaweed - brown, green, red, blue-green and others. Seaweed treatment is based on the fact that they contain a large amount of iodine, sea gum, vegetable mucus, chlorophyll, alginic acids, sodium, potassium, ammonium salts, and vitamins. In cosmetics, mainly extracts of brown algae are used - fucus, kelp, cystoseira. Speaking about the benefits of algae for humans, we must not forget that the extracts obtained from certain types of algae differ in their composition and therefore have a directed effect.

Vitamins in marine and freshwater algae

Especially high is the content in freshwater and seaweed of such vitamins as A, B1; B2, C, E and D. Algae also contain a lot of fucoxanthin, iodine and sulfoamino acids. The importance of algae in human life lies in the fact that they are able to stimulate and regenerate skin cells, have a softening and light bactericidal effect. In others, moisturizing and moisture-retaining properties are clearly manifested due to the higher content of polysaccharides, organic acids, and mineral salts. Still others - due to the active effect of organic iodine, fucosterol, mineral salts and vitamins, they are effective against cellulite, acne, are favorable for oily skin care, as they provide regulation of fat metabolism and improve blood circulation.

In modern cosmetic practice, seaweed extracts are used in almost all types of skin and hair care products.

The main groups and features of algae, their classification

Speaking about the role of algae in human life, one cannot but recall the modern theory of the origin of life, which states that bacteria were at the origins of all life on Earth. Later, some of them evolved, which gave life to microorganisms containing chlorophyll. This is how the first algae appeared. Being capable of utilizing solar energy and releasing oxygen molecules, they were able to take part in the formation of a shell of atmospheric oxygen surrounding our planet. Thus, those forms of life on Earth that are familiar to modern man became possible.

The classification of algae in the general table of development is difficult. Plant organisms, called "seaweeds", are a highly arbitrary community of closely related organisms. Based on a number of features, this community is usually divided into several groups. There are 11 main types of algae, and the difference between brown algae and green algae is more significant than the difference between green algae and higher plants, such as grasses.

At the same time, all groups of algae have chlorophyll, a green pigment that is responsible for photosynthesis. Since only one of the groups of algae, the green ones, has the same composition and ratio of pigments as those of higher plants, it is believed that they are the ancestors of forests.

In addition to green, algae are blue-green, blue, red, brown. But regardless of color, all the huge number of species known to us, first of all, is divided into two large groups - unicellular and multicellular. Photos of the main types of algae are presented below on this page.

What are the main types of algae

The main groups of algae include microscopic unicellular and large multicellular.

Microscopic unicellular algae represented by a single cell that is able to provide all the functions of the body. As you can see in the photo, these algae are in the range of several tens of microns (l micron is a thousandth of a millimeter). Most of them are adapted to a floating lifestyle. In addition, many species have one or more flagella, which make them very mobile.

The second main type of algae is large multicellular- consist of a large number of cells that form the so-called thallus, or thallus - what we perceive as an individual algae. The thallus consists of three parts:

• fixing apparatus - rhizoid, with the help of which the alga clings to the substrate;
• stalk (legs), varying in length and diameter;
• plate, dissected into fibers in the form of strands or straps.

The size of the thallus is very different, depending on the type of algae. For example, the thallus of Ulva, or sea lettuce (Ulva lactuca), does not exceed a few centimeters. The peculiarity of these algae is that their extremely thin plate can continue to develop and grow even after separation from the substrate. Individual specimens of laminaria reach a length of several meters. It is their thallus, clearly divided into three parts, that well illustrates the structure of macroalgae.

The shape of the thallus is also very diverse. Marine calcareous deposits are known, consisting of algae of the genus Lithothamnium calcareum, which in life looks like a small pink coral.

The role and importance of freshwater algae in human life

What are the types of algae other than seaweed? The sea is not the only habitat for algae colonies. Fresh water ponds, small and big rivers is also their habitat. Algae live wherever there is enough light for photosynthesis.

So, even at great depths, near the bottom, seaweeds called benthic algae live. These are macroalgae that need a solid support for fixing and development.

Numerous microscopic diatoms live here, which are either located on the bottom or live on the thallus of large benthic algae. A huge amount of marine microscopic algae forms a significant part of the phytoplankton that drifts with the flow. Seaweed can be found even in water bodies with high salinity. Small algae, multiplying, can color the water, as happens in the Red Sea due to the microscopic alga Thishodesmium, which contains a red pigment.

Freshwater algae are usually represented by fibrous forms and develop on the bottom of reservoirs, on rocks or on the surface of aquatic plants. Freshwater phytoplankton is widely known. These are microscopic unicellular algae that live in literally all layers of fresh water.

Freshwater algae have quite unexpectedly succeeded in settling other areas, such as residential buildings. The main thing for any algae habitat is humidity and light. Algae appear on the walls of houses, they are found even in hot springs with temperatures up to +85 °C.

Some single-celled algae - mainly zooxanthelles (Zooxanthelles) - settle inside animal cells, staying in a stable relationship (symbiosis). Even the corals that make up coral reefs cannot exist without symbiosis with algae, which, thanks to their ability to photosynthesis, supply them with nutrients needed for growth.

Laminaria is a brown seaweed

What are algae, and in what industries have they found their application? Currently, about 30,000 varieties of algae are known to science. In cosmetology, brown algae have found their application - kelp (seaweed), amfeltia and fucus; red algae lithotamnia; blue-green algae - spirulina, chrocus, nastuk; blue algae- spiral algae and green algae ulva (sea lettuce).

Laminaria is a brown algae, which was one of the first to be used in cosmetic products. Despite the fact that there are several types of kelp, outwardly very different from each other, they all live only in cold, well-mixed water. The most famous is the sugary kelp (Laminaria Saccharina), which lives off the European coast and owes its name to the sweet taste of the mucus covering it. It grows in bushes, the size of which is directly dependent on the degree of protection of the habitat. It reaches 2-4 meters in length, its stem is cylindrical, turning into a corrugated long plate.

Wide famous name"sea kale" is historically associated with the palmately dissected kelp (Laminaria digitata), living in places protected from the surf at the uppermost boundary of the sublittoral zone - the sea shelf zone. Otherwise, kelp is called the "witch's tail." The thallus of this alga, reaching a length of 3 meters, is an excellent good example general plan of the structure of macroalgae. Rhizoids (trailers), palmate, branched, with which the alga is attached to stones, are very clearly visible; stem - long, cylindrical, flexible and smooth; the plate is flat, solid in the lower section, and then dissected into straps. This type of algae is especially rich in iodine, since kelp is always under water.

The use of algae of this species has been established on an industrial scale. In addition to its nutritional purpose, it has valuable pharmacological properties. This type of kelp is especially known for its stimulating and tonic effect: it improves overall metabolism, is a source of trace elements and is widely included in weight loss products and anti-cellulite programs.

Numerous studies have shown that sea kale (and other algae) is different in that none of its constituent components is harmful to patients, including those with malignant processes.

Fucus (fucus) is the second most important for cosmetics algae from the class of brown (Phaeophycophyta). Grows on rocks coastal zone and collect it by hand. The beneficial properties of these algae are due to the fact that they are extremely rich in iodine, vitamins, amino acids, plant hormones and trace elements. You can find it on the beaches of the English Channel and along the entire Atlantic coast. For cosmetic purposes, two varieties of fucus are commonly used:

Fucus vesiculosus

and Fucus serrafus.

The presence of a large amount of alginic acid determines the natural gelling and thickening ability of extracts, both kelp and fucus. Both algae are rich in organic and inorganic substances, which determine their high biological activity. Extracts of kelp and, to a greater extent, fucus vesiculosus (Fucus vesiculosus) contain a complex of substances that stimulate the work of β-receptors and block α-receptors of fat cells, providing an effective anti-cellulite effect.

What is it - red, blue and green algae (with photo)

Red algae is a division of algae that lives in sea water.

lithotamnia (Lithothamnium), like all red algae, they are found on the underwater rocks of the North Sea, the English Channel and the Atlantic. It was colorfully described in 1963 by the famous submariner Jacques Cousteau. At a depth of a hundred meters, he discovered a red beach - a platform of calcareous purple - lithotamnia. This seaweed is similar to big chunks pink marble with uneven surface. Living in the sea, she absorbs and accumulates lime. The calcium content in it is up to 33% and magnesium up to 3%, and besides, it has an iron concentration 18,500 times greater than sea ​​water. Lithotamnia is mined mainly in Britain and Japan. It is included in the composition of cosmetic products, given the ability to restore the balance of minerals in the body, but it is also popular as a dietary supplement.

In face and especially body care products developed in recent years, the use of a mixture of fucus, kelp and lithotamnia algae is common. Rich in inorganic compounds, lithotamnia perfectly complements the action of brown algae, providing a comprehensive effect on the skin and hair.

Blue algae are spiral algae found in some lakes in California and Mexico. Due to the high content of protein, vitamin B12 and P-carotene, they improve skin elasticity and have a wonderful firming effect.

See how blue algae look in the photo - they differ from other algae in a rich blue-turquoise color.

Green algae are a group of lower plants. Ulva (Ulva lactuca)- sea lettuce - is a green algae that grows on the rocks. You can collect it only at low tide. Sea lettuce is a real pantry of B vitamins and iron, they help strengthen body tissues and improve blood circulation in capillary vessels.

Spirulina is a blue-green seaweed, its use for treatment. Spirulina from more than 30,000 species of algae contains the richest set of vitamins, microelements, amino acids, enzymes. It is rich in chlorophyll, gamma-linoleic acid, polyunsaturated fatty acids and other potentially valuable nutrients such as sulfolipids, glycolipids, phycocyanin, superoxide dismutase, RNase, DNase.

Spirulina differs from other algae in that it contains up to 70% of the most perfect protein in its composition, no other representatives of the flora and fauna on Earth contain such an amount.

Spirulina is the richest source of natural P-carotene, a vital antioxidant, and other carotenoids. Carotenoids are used by several organs in our body, including the adrenal glands, the reproductive system, the pancreas and spleen, the skin, and the retina of the eyes.

Only spirulina and mother's milk are complete sources of gamma-linoleic acid (GLA), which plays an indispensable role in ensuring the normal functioning of the body, all other sources are extracted oils. GLA helps prevent heart attacks and strokes, helps to remove excess fluid, improves function nervous system and regulates cell reproduction, has anti-inflammatory properties, maintains healthy joints, and helps treat arthritis. GLA is also recognized important element nutrition, to prevent skin diseases such as psoriasis. Spirulina contains the most perfect protein and all essential amino acids. Spirulina protein does not require heat treatment for consumption, while other protein-containing products must be cooked or baked (cereals, meat, fish, eggs), as a result of which some forms of protein partially, and some completely lose their useful qualities.

Spirulina does not contain rigid cellulose in its cell walls, unlike other algae, but consists of mucosol saccharides. This allows its protein to be easily digested and assimilated in the body. Protein digestion is 85-95%.

Algae are the most ancient plants on Earth, living in water, on soil, on the bark of trees, and also forming a symbiotic organism - lichen.

They are the initial link in the food chain, representing food for animals, from protozoa to mammals. In addition, algae in the process of photosynthesis release oxygen into the water, which makes it possible for animals to breathe in water both in the seas and oceans, and in small ponds and puddles.

In the thickets of algae, many invertebrates and juvenile fish and amphibians find shelter and habitat.

For the normal state of biocenoses of water bodies, everything must be in balance - both plant resources and the number of animals. To maintain this balance, it is necessary that the reservoirs be environmentally friendly - they would not dump sewage, chemical waste, scrap metal, rotting wood and non-decaying synthetic materials, as this leads to a sharp decrease in the amount of oxygen, an increase in acidity, an increase in the number of putrefactive and pathogenic bacteria. This inevitably leads to the death of plants and animals, human diseases and the appearance of dead and contaminated seas, lakes, and ponds on Earth.

Structure

Algae are lower spore plants containing chlorophyll in their cells and living mainly in water. In morphological terms, for algae, the most significant feature is the absence of a body divided into stems, leaves, and roots. Their body is designated as a thallus (or thallus). They reproduce vegetatively or with the help of spores, that is, they belong to spore plants. Physiologically, algae differ sharply from other groups of lower plants in the presence of chlorophyll, thanks to which they are able to assimilate carbon dioxide, i.e., feed photoautotrophically. Unlike algae, bacteria that are green in color contain a pigment that is close to chlorophyll, but not identical to it.

Algae, even the simplest of them - blue-green, are the first organisms that, in the process of evolution, acquired the ability to carry out photosynthesis using water as a source (donor) of hydrogen and the release of free oxygen, i.e. process in higher plants. The second feature of the nutrition of algae and other photosynthetic plants is the ability to assimilate nitrogen, sulfur, phosphorus, potassium and other mineral elements in the form of mineral salt ions and use them for the synthesis of such important components of a living cell as amino acids, proteins, nucleic acids, macroergic compounds, substances secondary exchange. Among the algae, there are species that are strict photosynthetics (from blue-green - anabens, some strains of nostocs; from green - some types of chlorococcus, chlamydomonos).

Many algae, under certain conditions, can easily switch from the photoautotrophic mode of nutrition to the assimilation of various organic compounds, i.e., carry out hetero- or photoheterotrophic (combination of heterotrophic and photoautotrophic) types of nutrition.

The basic structural unit of the body of algae is the cell. Siphon algae constitute a unique group: their thallus is not divided into cells, but there are unicellular stages in the development cycle.

Multicellular forms arose after the cell had undergone a long and hard way development as an independent organism. The transition from a unicellular to a multicellular state was accompanied by a loss of individuality and related changes in the structure and functions of the cell. With the emergence of multicellularity, differentiation and specialization of cells in the thallus are associated, which should be considered as the first step towards the formation of tissues and organs.

Brief description of individual representatives of algae

There is a huge variety of shapes (spherical, pear-shaped, ovoid, fusiform, spiral, cylindrical, etc.) and sizes (from a few micrometers in blue-green to several centimeters in Chara) algal cells.

reproduction

Reproduction is distinguished:

• vegetative [show] .

  Vegetative- division of individuals in two. Sometimes the division is preceded by the death of individual cells (in blue-green ones), sometimes special formations serve for vegetative propagation: buds on the thalli of sphacelaria from brown algae; unicellular or multicellular nodules in charophytes; akinetes (sometimes called spores) are cells that can survive adverse conditions in filamentous blue-greens. Vegetative reproduction is a form of asexual reproduction.

• asexual [show] .

  asexual reproduction is accompanied by the division of the protoplast of the cell into parts and the release of fission products from the membrane of the mother cell. Asexual reproduction occurs through spores or zoospores (spores with flagella). They are formed in cells that do not differ in shape from other cells, or in special cells - sporangia, which may have a different shape and size than vegetative ones. The main difference between sporangia and other cells is that they arise as outgrowths of ordinary cells and perform only the function of forming spores.

  Dispute types:

  1. aplanospores - spores that are dressed in a shell inside the mother cell;
  2. autospores - aplanospores, which in the mother cell acquire a similar shape.

  According to their number in sporangia, tetraspores (many red and dictyota from brown), biospores (coralline from red) and monospores (some red) are distinguished.

  Spores and zoospores usually enter the water through a hole in the sporangium wall as a whole group, surrounded by a mucous membrane, which soon blurs.

• sexual [show] .

  sexual reproduction It consists in the fusion of two cells (gametes), as a result of which a zygote is formed, which grows into a new individual or gives zoospores.

  Types of sexual reproduction:

  1. connection of the contents of two vegetative cells (hologamy - the fusion of two individuals in Volvox; conjugation - the fusion of the contents of two non-flagellated vegetative cells in green algae conjugates);
  2. the formation of specialized germ cells-gametes inside the cells (male gametes have flagella, female - not always). The receptacles of gametes are called gametangia.

  Depending on the relative size of gametes, there are:

  • isogamy - gametes of the same size and shape;
  • heterogamy (anisogamy) - the female gamete is larger than the male, but similar to it;
  • oogamy - the female gamete (ovum) is devoid of flagella, motionless, much larger than the male, which is called a spermatozoon or antherozoid; gametangia containing an egg are called oogonia, the male gamete is spermatangia or antheridia;
  • autogamy - a special type of sexual process (in some diatoms), which consists in the fact that the cell nucleus is previously divided into 4 nuclei with meiosis, two of them are destroyed, and the remaining two merge, again forming a diploid nucleus. Autogamy is not accompanied by an increase in the number of individuals, but only by their rejuvenation.

  As a result of the fusion of gametes, a zygote is formed, the flagella fall off, a shell appears (if the flagella persist for some time, the zygote is called planozygote). In the zygote, two nuclei merge - it is diploid. In the future, the zygotes of various algae behave differently: some become covered with a thick shell and fall into a dormant period lasting up to several months; others germinate without a dormant period. In some cases, new thalli grow from the zygote, in others, zoospores form from the zygote.

  There are algae in which the organs of asexual and sexual reproduction develop on different individuals; then plants that form spores are called sporophytes, and plants that produce gametes are called gametophytes. In other algae, spores and gametes are produced on the same plants.

Distribution in nature

According to the conditions of existence, algae can be divided into two groups: living in water and living outside water.

Aquatic organisms are divided into planktonic (they are suspended in water and have a number of adaptations to these living conditions), benthic (located at the bottom of water bodies), periphyton (underwater rocks, higher aquatic plants, underwater objects), neuston (float in a semi-submerged state on the water surface at the water-air interface). Algae living outside the water are divided into aerophyton (terrestrial fouling) and soil.

In addition to the above groups, hot spring algae are distinguished (their typical inhabitants are blue-green, there are few specific thermophilic forms - mastigocladus, formidium); snow and ice algae (the phenomenon of "red snow" causes snow chlamydomonas; 80 species of "ice" diatoms); algae of salt water bodies (dunaliella salt from volvox, chloroglea sarcinoid from blue-green); algae in a limestone substrate (drilling and tuff-forming algae - giella, rivularia).

Departments of algae

Separation of algae into systematic groups- departments - basically coincides with the nature of their color, associated, of course, with structural features. The most widespread division of algae into 10 departments:

1. blue-green [show] .

   blue green algae bluish-green, sometimes almost black-green or olive-green. Pigments: chlorophyll a, carotenoids, blue phycocyanin, a small amount of red phycoerythrin. Forms are predominantly multicellular, colonial or filamentous, there are unicellular. The shells consist of murein, pectin, sometimes cellulose, and are mucilaginous. The characteristic structure of cells: there is no differentiated nucleus, chloroplasts, vacuoles, photosynthetic membranes, pigments and nucleoproteins are located in the cytoplasm - the main component nuclei of other plants. Many blue-green algae have a network of gas vacuoles in the cytoplasm, and a significant number of filamentous algae form so-called heterocysts - cells with a specific structure.

   Reproduction in unicellular occurs by cell division, in colonial and filamentous - by the disintegration of colonies and filaments, there is a sexual process. In many blue-greens, spores are formed to endure adverse conditions and for reproduction.

2. pyrophytic [show] .

   pyrophytic algae- unicellular, an essential feature is the dorsal-abdominal (dorsoventral) structure of their cells (the dorsal, ventral and lateral sides, anterior and posterior ends are clearly expressed). The presence of grooves is characteristic, there may be two (longitudinal and transverse) or one (longitudinal). There are two flagella of different lengths, a pharynx (looking like a bag, a pipe, an inner pocket or a triangular reservoir), bodies that strongly refract light - trichocysts (located in the peripheral layer of the cytoplasm, on the inner surface of the pharynx or inside the protoplast). They are usually painted in olive, brown or brown, often yellow, golden, red, less often blue, blue. Pigments: chlorophylls a and c, xanthophylls, peridinins. There are colorless forms. Nutrition is autotrophic, rarely heterotrophic. Reproduction is mainly vegetative, rarely asexual (zoo- and autospores). The sexual process is unknown.

   They are widely distributed in the water bodies of our planet (fresh, brackish waters, in the seas).

3. golden [show] .

   golden algae- predominantly microscopic, unicellular, colonial and multicellular forms. Painted in golden yellow. Pigments: chlorophylls a and c, carotenoids, especially fucoxanthin. They live mainly in clean fresh waters, characteristic of the acidic waters of sphagnum bogs. Some species live in the seas. Usually develop in early spring, late autumn and in winter.

   The structure of the cell is the same: in the protoplast there is one or two parietal trough-shaped chloroplasts with a pyrenoid, the nucleus is small, in some species there are one or two pulsating vacuoles on the front of the cell. Shell: in the simplest representatives - a delicate periplast; in most golden ones, the periplast is dense, the cell has a constant shape; in highly organized representatives - a real cellulose, usually double-circuit shell. In many species, the cells are covered with a shell with spines and needles.

   They reproduce by simple cell division or the breakdown of the thallus into parts. Asexual reproduction is observed with the help of zoospores, less often autospores. The sexual process is known in the form of a typical isogamy, autogamy.

4. diatoms [show] .

   diatoms- microscopic unicellular, colonial or filamentous algae of brownish-yellow color. Pigments: chlorophylls a and c, carotene, fucoxanthin and other xanthophylls. The shape of the cells is varied. The shell is represented by a shell of silica, lined from the inside with a pectin layer. In the flint shell there are pores - areoles. Depending on the configuration of the cells and the structure of the valves, diatoms are distinguished with radial and bilateral symmetry.

   Many diatoms have a longitudinal gap in the valves (the so-called seam). At its ends and in the middle there are thickenings of the shell, which are called nodules. Thanks to the seam and knots, the cell moves. Algae that do not have a seam do not move.

   Protoplasm is located in the cells in a thin layer. The cell contains a nucleus, a vacuole with cell sap. Chloroplasts have different shape, there may be one or more.

   Diatoms reproduce by division. They also have a sexual process, usually associated with the formation of auxospores, that is, "growing spores", which grow strongly and then germinate into cells that differ significantly in size from the original ones. Auxospores are characteristic only of diatoms. Diatoms can form resting spores.

   They live everywhere: in water bodies (fresh and salty), in swamps, on stones and rocks, in soils and on their surface, on snow and ice.

5. yellow-green [show] .

   yellow green algae- unicellular, colonial, multicellular and non-cellular forms. Most are immobile, but there are mobile forms.

   This section has recently been isolated from green algae. Yellow-green algae are distinguished by the fact that the two flagella of their zoospores are not the same in location and structure: one is longer, directed forward, has processes on the axis, the second is smooth, short, directed backward. The cell membrane contains a lot of pectin substances, does not react to cellulose.

   The cell structure of yellow-green algae is the same. In the protoplast, there are several chloroplasts that have a disc-shaped, trough-shaped, lamellar, less often ribbon-like, stellate shape. The main pigments are chlorophylls a, e, carotenes and xanthophylls. In mobile forms, a red eye is located at the anterior end of the chloroplast. The core is one. Few species have a pyrenoid and one or two pulsating vacuoles in the anterior part of the cell.

   Vegetative reproduction occurs by cell division, the collapse of colonies or filaments, asexual reproduction - by zoo- and autospores. The sexual process is known for a small number of genera: iso-, oogamy.

   Distributed in plankton, benthos of fresh water bodies, in the seas, soil, in places with high humidity.

6. brown [show] .

   brown algae- in most cases, these are marine forms. They are multicellular, attached to the substrate. Their sizes vary from a few millimeters to several meters, there are species that reach 60 m.

   In appearance, these are branched bushes, plates, cords, ribbons, some seem to have a stem and leaves. The cell has one nucleus, chloroplasts are brown, granular, often there are many of them. Pigments: chlorophylls a and c, carotenes, many fucoxanthins.

   In multi-row thalli, specialization of cells with the formation of tissues is observed. In the simplest case, a cortex (intensely stained cells containing chloroplasts) and a core (colorless large cells of the same shape) are distinguished. In more complexly organized ones (kelp and fucus), there is also a surface layer of dividing cells capable of producing reproductive organs and called the meristoderm, and an intermediate layer between the core and the cortex. The core serves to transport the products of photosynthesis and performs a mechanical function.

7. red [show] .

   Red algae (crimson)- an extensive group among bottom seaweeds. They are very rarely found in fresh water bodies (batrachospermum species), in terrestrial fouling (porphyridium). They are painted in various shades of red, some have a yellowish, olive or bluish-green color.

   Pigments: chlorophylls a and d (the latter is found only in red algae), carotenes, xanthophylls, R-phycoerythrin, R-phycocyanin. Almost all red algae are multicellular, in the form of filaments, branched filaments, bushes, some have stem-like and leaf-like organs. There are no such large sizes like brown ones. All are attached to the substrate. Cells are covered with a membrane consisting of two layers: inner - cellulose and outer - pectin. In the most simply organized cells, the cells are mononuclear, in the highly organized, they are multinuclear. There is one or more chloroplasts. A feature of red algae is the presence of special glandular cells in some representatives. The cells that make up the thallus are connected by pores.

   Vegetative reproduction is rare. In the asexual process, zoospores are completely absent. The sexual process is oogamy.

   Bagryanki have a peculiar structure of oogonium (karpogon) and complex processes of zygote development. There are no mobile stages in the development cycle. The zygote, before giving rise to the sporophyte, undergoes a complex development, as a result of which spores (carpospores) are formed, giving rise to the sporophyte.

8. euglenoids [show] .

   Euglena algae- microscopic organisms. The shape of the cells is mainly elliptical, fusiform. Chloroplasts are stellate, ribbon-like, large-lamellar.

   Pigments: chlorophylls a, b, carotene, xanthophylls. Some euglenoids have a red pigment, astaxanthin, which regulates the amount of light that reaches the chloroplasts. In conditions of intense illumination, the pigment accumulates in the peripheral part of the cell and obscures the chloroplasts. The cell is then colored red. There is no cellulose membrane, its role is played by a compacted layer of the cytoplasm; some have a shell that is not tightly bound to the protoplast. At the front end of the body there is a depression (pharynx), from the bottom of which one or two flagella extend. Euglenoids move by changing the shape of the body and with the help of a flagellum, simultaneously turning around the longitudinal axis. In living euglenoids, in the front of the cell there is a red spot - a stigma, which acts as a light-sensitive organ. Reproduce by longitudinal division. The presence of a sexual process has not been established. They live mainly in small fresh water bodies, some in brackish ones.

9. green [show] .

   green algae- this is the most numerous department (up to 20,000 species). Purely different in green their thalli.

   Pigments: chlorophylls a and b, carotenes and many xanthophylls. In some species and at some stages of development, the green color may be masked by the red pigment hematochrome. Unicellular, colonial and multicellular forms. Sizes: from the smallest single cells with a diameter of 1-2 microns to macroscopic plants measured in tens of centimeters in length. In green algae, all the main types of asexual and sexual reproduction and all the main types of change in developmental forms are found.

10. characeae [show] .

    Chara algae- a peculiar group of algae, in appearance resembling higher plants. Widespread in freshwater ponds and lakes, especially in hard lime water; found in sea bays and in brackish continental waters. They form thickets. The height of their thalli is usually 20-30 cm, but can reach 1 or even 2 m. They look like bushy filiform or stem-like green shoots of an articulated-whorled structure: on the main shoots, conventionally called stems, whorls of lateral shoots are located at some distance from each other - conditionally leaves - also a segmented structure. The locations of the whorls are called nodes, and the sections of the stem between them are called internodes. Cells of nodes and internodes are different: an internode is a giant elongated cell that is not capable of dividing; the node consists of several small mononuclear cells assembled in a disk, differentiating in the process of division and forming lateral branches and a whorl.

    Chloroplasts are numerous, have the form of small discoid bodies (reminiscent of chlorophyll grains).

    Pigments: chlorophylls a and b, carotenes, xanthophylls (similar to green algae). The structure of the organs of sexual reproduction, which are formed on top of most segments - leaves, is peculiar. Female organs - oogonia - and male - antheridia - are multicellular, usually develop on one plant (they are rarely dioecious).

The role of algae in nature, their economic importance

Algae is one of ancient organisms that inhabit our planet. In past geological eras, as at the present time, algae inhabited the oceans, rivers, lakes and other bodies of water. Enriching the atmosphere with oxygen, they brought to life diverse world animals and contributed to the development of aerobic bacteria; they were the ancestors of plants that populated the land, and created powerful strata of rocks.

Algae, like higher plants on land, are a source of organic matter, oxygen producers in water bodies. As a result of the activity of algae (mainly diatoms, blue-green and green), rocks are formed (diatomites, siliceous deposits, some limestones). Some algae (drilling blue-green), destroying rocks, are involved in the formation of primary soils.

In combination with other organisms (bacteria, fungi), algae take part in the process of self-purification of water.

However, developing in large numbers, algae (blue-green, some green, diatoms, pyrophytes) can lead to "water bloom", during which a significant number of organisms settle to the bottom, decay processes intensify, the amount of oxygen sharply decreases and the concentration of carbon dioxide increases. This leads to summer kill of fish. "Blossoming" negatively affects the water supply (filters become clogged, water acquires an unpleasant taste and smell).

In agriculture, algae are used as organic fertilizers (nitrogen-fixing blue-green algae, seaweed, as well as the mass of blue-green algae, which is collected during the "bloom" of reservoirs). Algae determine the formation of humus, improve soil aeration, and affect its structure.

Algae are raw materials for obtaining valuable organic substances: alcohols, ammonia, varnishes, organic acids, etc. (sapropels); iodine, bromine (brown algae); glue (kelp); agar-agar (red algae, phyllophora), carotene, biologically active substances. Used in the microbiological industry, space research. For the production of paper and cardboard, cladophora and rhizoclonia are used, which develop in large numbers in the reservoirs of Western Siberia. Seaweeds are used in the food industry, as well as directly in food (seaweed, sea lettuce, nostocs).

In sanitary hydrobiology, algae are used as indicators showing the degree of water pollution with organic substances. Algae is used to purify industrial waters.