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by Yekaterina BLINOVA, Cand. Sc. (Biol.), Leading Research Scientist, All-Russia Research Institute of Sea Fishing and Oceanography
Seaweeds (algae) are the oldest photosynthetic organisms of the earth known to have created its oxygen atmosphere. The land plants come from them. The role of this wonderful family of the plant kingdom is immense indeed. First and foremost, the algae are the primary "producers" of organic matter from inorganic one, the cornerstone of our planet's ecological pyramid. Although their biomass in the World Ocean is something like 1.7 bln tons, their annual produce amounts to as much as 550.2 bln.
Marine life, especially in the off-shore zones subject to anthropogenic effects, owes its existence to algae in the long run. They bring down water pollution, they give food and shelter to many invertebrates and fish - to fry in the first place, and they serve as a substrate (attachment base) for sea animals and fish roe.
Algae are quite diverse in color, size, structure and form: they may be filamentous, laminar and ramified (branched). Some have small stems and what looks like leaflets; and those growing on solid ground are supplied with anchoring organs like rhizoids, soles and suckers.
Physiologically, sea plants are precious. Their layers accumulate, selectively, mineral elements at concentrations dozens and even thousands of times as high as the ambient water. Large algae, the macrophytes, absorb light and nutrients by their entire surface.
Our country is washed by thirteen seas, mostly in the temperate zone. The total biomass of seaweeds tops 10 mln tons, and their yearly produce is severalfold as high. Our seas are inhabited by 850 - 900 macrophyte species (around 170 species of green algae, about 250 red and 450 brown algae species) as well as a variety of sea grasses (Monocotyledoneae) .
The offshore macrophytobentos is formed for the most part by brown - laminar and focus (Fucaceae) - algae, which are the largest. They build the upper, dominating tier of sea vegetation, its layers being the substrate for sun algae, the epiphytes. The lower rungs are occupied by smaller plants. Thus multitier structures arise, the home for invertebrates and fish. In fact, here we are dealing with complex and highly productive colonies of diverse living organisms.
And yet the species-specific makeup of algae and their biomass are undergoing significant changes due to water pollution: large perennial forms are on the way out to give place to annual and seasonal varieties. Russian algologists-specialists involved with seaweeds - are keeping a tab on these trends. Our institute and other research centers here in Russia are studying the algal taxonomy, the vertical and horizontal distribution of algae depending on the geographical position of particular seas and ecological conditions. We are monitoring the vital activity of separate communities. Special attention is given to the biology of plants most useful to man. We are checking on their reserves, and working out commercial regulations for each particular plant and each particular region.
Simultaneously, we are carrying out a good deal of work in determining the chemical composition of seaweeds and in developing alternative production technologies for obtaining various substances from them - those having no analogs-or else their natural and artificial substitutes. Yet another line of our activity is to develop cultivation methods for particular sea products on plantations or in special receptacles under controlled conditions. Incidentally, the former variant (marine plantations) is most advantageous economically and holds the best promise. Gaining wide use now are our methods of growing sea kale, the Laminaria japonica (Sea of Japan), and L.saccharina (Barents and White Seas). Even though artificial cultivation has its specifics in each particular region, the general principles are the same.
First we choose places safe against storms, 10 - 50 m deep, with soft ground and good water circulation. The framework of a sea plantation is built of 50 - 100 m-long ropes drawn taut with the aid of anchors and buoys. In the meantime breeder layers are prepared. They are dried a little to secure the simultaneous and rapid output of spores. The breeder plants are placed into vessels of non-toxic material, which are then filled with water. Capron ropes previously allowed to soak in sea water for a time are immersed into the suspension for the spores to attach. Thereupon these substrates are tied to the ropes at 50 cm intervals. The seedlings have to be tended - thinned out, for one. The plants thus removed could be set out on other plantations. This method of cultivation is in a biennial cycle, and the crop is from 40 to 70 tons per hectare.
Seaweeds have a wide range of applications. Many are consumed as health foods. In our country, this is sea kale (laminaria) in the first place. Doctors say that bread, if 3 to 9 percent of kale is added to it, can be recommended to everybody. Sea kale can also be added to marshmallows, fudge, drops, marmalade and nonalcoholic beverages (1 - 9 percent). This sea food helps increase the amount of blood erythrocytes and hemoglobin. Laminaria weeds are much needed to the organism after surgeries and radiation therapy, in thyroid gland dysfunctions, and during atherosclerotic forms of hypertension. Sea foods are also the givers of organic acids and such microelements as calcium, magnesium, cobalt, copper, potassium, iodine, among others. They supply us with C and B vitamins, carotene, and so on.
Algae are an excellent food additives in stock fur, and poultry farming. The animals and fowl gain in weight and in health. Cows give better yields of milk with higher content of fat and vitamin A; the egg-layers boost their productivity, while fur animals have fewer cases of mortality and improve their fur quality.
All seaweeds, even those no good for food, can be utilized as a fertilizer that contains essential macro- and microelements, growth stimulants and organic substances; this fertilizer improves the soil structure, hygroscopicity and mellowness. Algal byproducts can likewise be used as animal feed additives.
Russian scientists have also developed methods of extracting such valuable substances from sea products as alginates, agar, agaroid or carragheena. Since all these substances are good as gelatins, they are used in the food industry as emulsifying agents, stabilizers and stiffeners.
Thus, alginates-the salts of alginic acid obtained from brown algae - are added to ice creams, sauces, mayonnaise, margarine, jellies, jams, cheese, fish or meat in aspic, powder fruit juices; and to frozen fish so as to improve its quality and prolong its shelf life. These substances have found many uses in medicine as hemostatics, in the manufacture of resolvable surgical threads, of dental casts, ointments and pill coatings. Alginate-based preparations are very effective as a remedy for the prevention and treatment of intoxication caused by radionuclides, by heavy metals and for gastrointestinal diseases.
Perfumers, too, make use of these substances as thickening agents in creams, gels, toothpastes and shampoos; they are a component of detergents nice in hard and marine water. These substances have found broad uses in the textile industry (manufacture of waterproof fabrics, dyes), in paper production, and in the production of film for photography, cinematography and so forth.
High-quality (microbiological) agar has no substitutes as a solid nutrient medium in microbiology, virology, immunology, and in the making of vaccines, pills, salves, and pastes; it is essential in electrophoresis and for other purposes. Agaroid, the food agar, and carragheenan are important ingredients of marmalades, marshallows, ice creams, dishes in aspic, creams, mousses and preservatives added to beverages.
From sea grass (Zosterd) we get zosterine, a polysaccharide, which is used as preventive remedy and for medication in case of intoxication by radionuclides, by heavy metals and for the treatment of gastrointestinal disorders. The concentration of this valuable component in sea grass is as high as 10 to 25 percent, and its salts that form viscous solutions are used in the food industry as stabilizers. Besides, the sea grass is considered to be one of the best, ecologically pure and noninflammable materials that go into the stuffing and padding of soft furniture.
And now let's make a tour of the Russian seas and have a look how their gifts are distributed. Let's begin with the Far North, the Barents and White Seas, whose cold waters abound in brown algae (Phaeophyta) . The commercial laminariae are these: L.saccharina and L.digitata; Alaria esculenta the Fuci-Fucus serratus, F. vesiculosus and F.distichus and Ascophyllum nodosum . In the White Sea these weeds are picked mostly near the isles of Zhizhgin and Zhuzhmui, off the Solovetskie Islands, and off the Onega shores. The laminaria reserve there totals 450,000 - 550,000 tons, and of the fucus weeds-as much as 250,000 - 300,000. This region has been divided into 83 sectors, of which only a third part is open for commercial exploitation. That is to say, in each particular sector seaweeds can be harvested every third year. Harvesting regulations are rather stiff with respect to the amount of weeds taken out.
Sea kale is mown from boats or else by scuba divers. Other techniques are employed now and then too. The fucus weeds are cut off the seashore at ebb-tide; the weed carried ashore by waves is considered good, too.
The White Sea also has a small reserve of red algae (Rhodophyta) , namely Ahnfeltia plicata (3,000 - 4,000 tons) much needed in the national economy. But this weed can be harvested only when tidal waves carry it ashore, for otherwise its stock may be depleted.
Sea algae are frozen or dried for better storage. Since these weeds are highly hygroscopic, they should be kept safe against moisture, be it rain,
dew or fog. The White Sea "weed catches" are processed at Archangel: Laminariae are made into alginates and mannitol * Fuci - into alginates and feed middlings while Ahnfeltia is turned into agar.
Time was when this region had an abundance of Zostera . But early in the 1960s as good as all these seaweeds perished from some fungoid disease. The disappearance of Zostera had dramatic consequences for the ecology of the White Sea, for its flora and fauna. The point is that this weed was the main filter of fluvial suspension, and so now rocky bottoms have come to be covered with silt every here and there. Fortunately subwater meadows are making a recovery little by little.
As to the Barents Sea, its chief reserve of Laminariae is concentrated in ice- free waters off the Murmansk coast - in the bays of Bolshaya Volokovaya, Zubovskaya, Teriberskaya, Ivanovka and Drozdovka; off the islands of Kildin, Maly and Bolshoy Oleny (200,000 - 250,000 tons) and in the Lumbov Bay (300,000 tons). The reserve of fucus weeds is somewhat lower, down to 150,000 - 200,000 tons.
And now let's travel to this country's south. The waters off the northeastern coast of the Black Sea are inhabited by Cystoseira , a brown alga much in use for medicinal baths and in balneology in general. It produces alginates and biologically active substances, too. The Bay of Taman is rich in Zostera .
But the largest treasure store of marine flora is found in our Far Eastern Seas, abundant in a great variety of Laminariae , too. They occur in as many as seventeen genera; many are of commercial interest, such as several species of Laminaria, Alaria, Arthrothamnus, Kjell-maniella , among others. These sea-
* Mannitol - an alcohol whose molecule has six atoms; it belongs to the class of aliphatic, or acyclic, compounds in which carbon atoms form "open" linear or branched chains. - Ed.
weeds are profuse in the vicinity of the Commanders Islands (Commodores), and their reserve is estimated at 5,000,000 tons. As much as 200,000 tons is carried ashore yearly on the Bering Island between the capes Tolsty and Vaxel. The profuse growth of Laminaria , of Alaria flstulosa in particular, cause stagnation in coastal waters, it reduces the feed for mammalians and inhibits reproduction of fish. The natural balance was upset back in the 18th century as Steller's sea cow that fed on Alaria was wiped out.
In the Sea of Okhotsk, especially in the Yakshin Bay (Bolshoi Shantar Island) the width of an underwater forest along the shoreline ranges from 500 to 1,200 meters. Abundant seaweeds are found off the continental coast: about 1,000,000 tons of Laminariae , 7.5 mln tons of Cystoseira crassipes , and 0.8 mln tons of Fucus . Their thickets are the haunt for the spawning herring schools inhabiting the Sea of Okhotsk. Sea kale with fish roe on it is much in demand in Japan, and this is a good export item for us.
Around the Kurile Islands, stretching for 1,200 km from northeast to southwest and having a shoreline of 2,300 km, grow 233 algal species with a huge total biomass of 8 to 9 mln tons for Laminariae alone. The main commercial species are the Laminariae japonica, dentigera , and yezoensis; Arthrothamni kurilensis and bifidus ; as well Ahnfeltia tobuchiensis .
Off the Pacific shore of the Iturup Island the seaweed forests extend for 1,000 - 1,3000 meters seawards. Here the Arthrothamnus kuriliensis and Laminariae dentigera hold pride of place. A solid algal belt, 1 km wide on the average, along the Urup Island, staggers imagination. These are the lush fields of Alaria fistulosa (650,000 tons) that grows at a depth of 6 to 35 meters, and of Arthrothamnus kuriliensis (450,000 tons) and of other Laminariae with their mass totalling 1.2 to 1.7 mln tons.
A good commercial reserve of Laminaria japonica (around 230,000 tons), mostly used for food, is found in the Sea of Japan, off the Pacific seaboard and the southwestern shores of Sakhalin. This seaweed has a life cycle of two years, and it is not permitted to mow plants younger than that.
Much high in demand is another sea gift, the Ahnfeltia tobuchiensis , a red agar-containing alga that floats unattached. It is abundant in some of the bays and in the Starka Strait of the Peter-the-Great Bay (Sea of Japan), in the Bussa Lagoon (Sakhalin) and, most of all, in the Izmena Bay (Kuriles). Here this seaweed, growing 1 to 7 meters deep, builds a stratum 10 to 20 cm thick (and at least 50 cm in the middle), with a total area of 2.3 - 2.6 thousand hectares and a biomass of 80 - 125 thousand tons. Annually, not more than 10 percent of the total mass of this perennial alga can be harvested so as not to encroach heavily on the available reserve. Weeds thrown ashore by storm should be picked in the first place. If need be, nearby accumulations of this plant can be harvested; and only then will it be allowed to pick from the stratum proper.
Our Far Eastern seas boast of meadows under Zostera aziatica and marina , and Phyllospadix that grow on from the ebb-and-fiow zone to a depth of 10 m. These plants have 70 - 100 cm-long leaves, and one can harvest up to 8 kg per 1 sq. meter, but only in the summertime, for this weed grows to an optimal mass by June. The harvesting is done at a low ebb ashore and in shallow waters with the use of scythes and sickles, or by using scuba-diving outfit in deeper waters. Plants washed ashore by storm are quite fit, especially perennials if late in summer and early in autumn.
Clearly, the flora of the Russian seas is a horn of plenty. What we need is to learn to use this natural wealth sparingly, in moderation, so as to keep and multiply it for generations to come.
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