From the point of view of geographers, this part of the World Ocean cannot be called a sea. Its boundaries are determined by ocean currents, and they, as you know, are fickle. Nevertheless, this area of the Atlantic Ocean is so unique in many properties that scientists have isolated it and call it the Sargasso Sea.
Let's clarify - where should you look for this sea on the map, and why is it so remarkable?
The Sargasso Sea is unlike any other sea on our planet. The fact is that the rest of the seas are limited by continents, while the Sargasso Sea is limited by strong Atlantic currents: in the north - the North Atlantic, in the south - the North Passat, in the west - the Gulf Stream, in the east - the Canary. Over the years, the Sargasso Sea has been shrouded in many secrets. They say that it has stagnant waters, and this whole motionless surface is completely covered with algae. In fact, the waters in the Sargasso Sea are in constant motion. They are pushed from different sides by different currents, so the Sargasso Sea rotates clockwise. And there are not so many algae in it.
The Sargasso Sea is considered one of the most interesting biological mysteries. It is located between the Leeward and Bermuda Islands. The area y of the sea is about 6-7 million km2, which depends on the position of the currents. It is also customary to call the Sargasso Sea a biological desert, but this statement is incorrect. In addition to areas that are densely covered with algae, there are also many areas with clear water. The Sargasso Sea is inhabited by incredible creatures, as if descended from the pages of a fantasy novel. For example, this is a sargassum sea clownfish, a fish from the clown family, it has fins that resemble hands that stick to algae.
In Spanish, sargazo is a small grape variety, hence the name of the sea. When Columbus's ships made their way through the waters of the sea, the sailors drew attention to the berries with which the branches of algae were hung, very reminiscent of wild grapes. Wild grapes in Portuguese sounds like "saglazo", from this word comes the name of the algae, and then the sea itself.
By the way, the "berries" of algae are not fruits - sargassos have no fruits at all, since they reproduce by spores. These are specific floats filled with air and keeping the plant afloat.
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The Sargasso Sea is located on a large area in the direction between the Florida Peninsula and the Canary Islands. Its area is over 6 million square kilometers (determined by the boundaries of the currents). It is here that the circulation of powerful oceanic currents is formed - the Gulf Stream (in the west), the North Atlantic (in the north), the Canary (in the east) and the North Passat (in the south). The circulation of currents is directed clockwise (anticyclonic). The sea has no shores, if you do not take into account the volcanic Bermuda islands located within its water area.
The sea is located over the deep-water part of the Atlantic Ocean - the North American Trench. Its maximum depth is almost 7000 m.
The circulation of currents formed an area with warm surface waters in the Sargasso Sea. Even in the winter months, the temperature of the upper layers of the water does not drop below +18 degrees C. Summer temperature reaches +28 degrees C. The water here is of increased salinity and its layers are well mixed by currents, so the water is warm up to a depth of 400 m (up to +17 degrees C). There is no such warm water in the depths of the ocean even in the tropics.
This phenomenon adversely affected the development of phytoalgae - the foundation of the ocean food pyramid. The scarce microvegetation was the reason for the small amount of zooplankton in the Sargasso Sea, and, as a consequence, the poor fauna. No more than 60 species of representatives of the aquatic fauna live here.
Sargasso Sea However, the animals that have adapted to life in the Sargasso Sea are very peculiar and, in their own way, unique. But more on that later. Here I will just note that the small number of microorganisms in the sea is the reason for the extraordinary transparency of its waters.
Despite some fluctuations in the boundaries of the sea, due to changes in the currents forming these boundaries, the sea area has remained practically constant for many centuries. Even when the great Columbus first crossed its waters in his ships, the borders of the Sargasso Sea were about the same as they are today.
The water here is amazingly clear - visibility reaches 60 meters, which is much higher than in the Red Sea, which is considered a kind of standard for the purity of waters due to the absence of flowing rivers.
Strong winds very rarely blow over the sea - this is a quiet and calm area of the ocean among the whirlpool of currents. Prolonged and frequent calm during the time of sailing ships was a great inconvenience to mariners who waited for weeks on calmness among the endless smooth surface of the ocean. History also knows many cases of the death of ships in the local waters, because months of motionless waiting killed sailors with hunger and thirst.
But the main feature of the Sargasso Sea is that a huge community of floating marine organisms has been formed here, the likes of which are nowhere else. The basis of this unique community is brown seaweed - sargassum, which gave the sea its name.
Sargassos are represented here by three species, which differ slightly. These algae grow along the coasts of the West Indies and the American continent, where they are not floating, but take root in the bottom soil.
Frequent hurricanes in the Caribbean and the Gulf of Mexico pull out the Sargasso and carry them to the ocean by the winds, where they are picked up by the currents and gather in the vortex of the Sargasso Sea in huge quantities. The reserves of floating algae in the Sargasso Sea are estimated at about 10 million tons. However, this value, as you understand, is not constant. Nevertheless, floating accumulations of Sargasso form huge massifs with a density of up to 1-2 t / sq. Km, and the sea surface in places resembles a large olive-green meadow.
Sargassos have become a kind of floating home for many living organisms. Even the simplest phytoalgae settle on long (up to 2 m) yellow-brown leaves.
On the floating branches of the Sargasso, tubifex, moldy bryozoa, tiny crustaceans and crabs, shrimps, sea needles, horses and other aquatic animals settle. In huge accumulations of algae, jellyfish, siphonophores, anemones, bryozoans, flying fish, schooling fish and even larger inhabitants of the ocean find food. Corifenos (fish of the perch-like order, reaching a length of 2 m), numerous in these waters. These predators hunt mainly for flying fish, which escape from them with their unique ability to fly decent distances over the water.
Interestingly, almost all inhabitants of the Sargasso community have a body shape and color that perfectly hides them among the algae. The shape of the body, as a rule, resembles leaves and twigs, and the color of the body is yellow-brown with dark spots, perfectly masking animals in floating sargassos. Try to see the seahorse in the photo below among the sarkass branches!
Such is the sargassum sea clownfish - a fish of the anglerfish order. Its body looks like a twig of sargassum, and it lures prey with a special "fishing rod" - an outgrowth above the head. The movements of the tip of this "fishing rod" resemble a wriggling worm, which attracts potential prey.
I think that many people know the history of the discovery of the breeding site of the European eel.
For hundreds of years, humanity has been tormented by conjectures - where and how does this fish bring offspring? Just over a century ago, this centuries-old secret was discovered - eels breed in the Sargasso Sea! These fish spawn thousands of kilometers from European rivers and, giving life to a new generation, die in its waters. The translucent larvae hatched from the eggs, having gotten a little stronger, set off on a long journey to the shores of Europe on the "back" of the Gulf Stream. Once in the mouth of a river, the larvae settle here for several years, turn into adult eels and go where they were born.
Interestingly, eels helped scientists to discover at great depths of the ocean (and this is where these fish are on their way to their homeland), a current opposite to the direction of the Gulf Stream. It was named so - Antigulf Stream. It is this current that helps the eels to reach their spawning grounds.
Why did the common (European) eel choose such an exotic Sargasso Sea as its spawning place? There are various hypotheses about the causes of this eel migration. For one reason, eels are forced to go on such a long journey due to continental drift. The narrow body of water that divided Europe and America at the beginning of the Tertiary period as a result of the movement of Greenland, the continents of the North and South America, gradually expanded, eventually turning into the Atlantic Ocean. To assess the hypothesis, a small reference: the Tertiary period covers the period of time in the history of the Earth from the extinction of dinosaurs, about 65 million years ago, to the beginning of the last ice age - about 1.8 million years ago. According to this hypothesis, the spawning grounds of both European and American eels did not change, only the distance changed, gradually increasing,which European eels had to overcome to get to their usual spawning grounds. Are the habits of eels more stable than the position of continents on the surface of the Earth?
A more reliable hypothesis for the appearance of such a distant migration of European eels was proposed by the Soviet ichthyologist P. Yu. Schmidt. He suggested that the current long-distance migration of the eel is the result of a change in the hydrological regime in the post-glacial period (the current outlines of the continents have already been formed!). According to this hypothesis, cold waters prevailed in the North Atlantic Ocean. The warm current of the Gulf Stream ran in those days in a latitudinal direction: from the coast of America (approximately, from present-day Florida) it reached the Iberian Peninsula (approximately, the coast of Portugal). The reverse flow was also present: turning south off the coast of Africa and then returning the streams of water back to the shores of America. The zone of high water temperatures of 16-17 ° C at a depth of 400 m, suitable for spawning of eels, stretches in a latitudinal direction across the entire ocean.
In the eastern part of this latitudinal current, not far from the freshwater estuaries of the rivers, the common European eel spawned. In the western part, near the coast of America, the American eel spawned, the migration of which is relatively close to this day. Thus, the distance to spawning grounds for common and American eels was approximately the same. With the change and warming of the climate, the Gulf Stream began to unfold, deviating to the northeast, carrying the larvae and fry of the common eel to the shores of northern Europe. Eel fry - "glass eels", went deeper into the northern seas in search of freshwater areas in river estuaries. The area of deep waters with a temperature where eel spawns has narrowed to the size of the Sargasso Sea. Tracking the departure of the Gulf Stream to the northeast and the narrowing of the favorable spawning zone to the west,the migration of the eel changed, gradually increasing the maximum distance for the European eel.
In the story about eels, it can be noted that the American eel inhabiting North America, which spawns in another area of the Sargasso Sea, uses a separate branch of the current as a passing "transport", delivering it to American shores and rivers.
An interesting animal - the traveler crab is known for upsetting the crew of Columbus' ship as it moved across the sea. Seeing a crab sitting on a sargassum branch, the sailors decided that the land was somewhere nearby. You can imagine their disappointment when they realized that they were wrong.
Sea turtles also live here. In ancient times, there were a lot of turtles in the Sargasso Sea, and they even sometimes saved seafarers captured in the waters of the sea for a long time from hunger.
Today, unfortunately, the pollution of the seas and the uncontrolled capture of turtles, as well as the destruction of egg-laying, have led to a catastrophic decline in the number of these marine reptiles in many places on the planet. In the Sargasso Sea you can find such species of sea turtles as green, loggehead, bissa and ridley. Turtles feed on algae, invertebrates and even jellyfish.
Despite the great distance from the coast, sharks can also be found in the Sargasso Sea. Of course, here you will not see representatives of benthic and coastal species, however pelagic sharks are sometimes found here. Among such oceanic travelers, one can note the blue shark, mako, long-finned oceanic, silk, soup. It is quite possible that other species of cartilaginous predators, hitherto unknown to science, live in the gloomy depths of this sea. As in the entire World Ocean, the abyss here still keeps many secrets.
Since there are not so many people who want to splash among the scraps of algae in the Sargasso Sea, nothing is known about incidents of people with sharks in its waters.
In the Sargasso Sea there is the advantage of the algae of one species, Sargassum natans. Their peculiarity lies in the fact that they reproduce by means of fragmentation, that is, any piece can live independently, reproducing itself again and again.
The main food for organisms in the Sargasso Sea is precisely these algae, due to the fact that the water temperature here is very high, plankton cannot live in it.
The algae stems have cracks in which smaller algae, reminiscent of hanging corals, and tubules form. In some places, algae stalks are covered with spots, these are bryozoa, living organisms such as moss, found from the tropics to the poles. Elsewhere in the ocean, bryozoa emerge from fertilized eggs, but in the Sargasso Sea, they are already formed from the parent organism. They have special cilia with which they capture microorganisms and feed on them. However, if bryozoa ingest a lot of food that is heavier than their weight, they drown and die in the icy water. Miniature shrimps and crabs also live in the Sargasso Sea. If the algae to which they are attached sinks to the bottom, they move to another alga.
Many living organisms in the Sargasso Sea survive only due to their disguise. So, sea needles look like algae processes, shrimp have white spots on their shells that resemble bryozoa. The sea clown has a color like that of algae, therefore it is almost invisible among them. With a height of 18 cm, he can attack the body with a height of 20 cm. In case of danger, he scares off the enemy by swallowing water and taking the shape of a ball.
The Sargasso Sea has warm water, which is why American and European eels come to spawn there. In addition, there are no large predators in this place, so many species of fish also come here to lay eggs. The mystery of this place is that the eel returns to the algae of the Sargasso Sea to die in them.
For many centuries, the Sargasso Sea has been awe-inspiring among sailors. There are many legends about how ships got entangled in its algae and died, and the whirlpool born by the currents carried sailors to the bottom of the sea. Mysterious calm, mysterious fogs, thick algae haunt the human imagination. The earliest stories date back to the 5th century. BC e, therefore, already at that time sailors sailed in those places of the Atlantic.
However, sailing ships of the past centuries really got stuck in the Sargasso Sea. But not because of algae, but because of the eternal calm. Sometimes I had to stand for an infinitely long time. Often the ships ran out of food and drinking water. The horses transported by the ships, mad with thirst, threw themselves overboard and drowned. Therefore, the Sargasso Sea in past centuries was also called the Horse.
Many abandoned ships have been found in the Sargasso Sea, and because of this, it enjoys the notorious fame of a ship graveyard. Thanks to some novelists, the central regions of the Sargasso Sea gained fame as a fantastic kingdom, where once sunken ships packed with treasures are piled on top of each other, many of which have lain there for hundreds of years, and the inhabitants of this amazing kingdom, brought here by inexorable sea currents, are indifferent to treasures, useless to them.
The existence of the Sargasso Sea has been known for a very long time, but the first most striking characteristic was given to it by Christopher Columbus. In 1492 he sailed on the ship "Santa Maria" in search of a shortcut to India. The path was not easy. People were looking forward to the appearance of the earth. But what at first the sailors took for the mainland turned out to be an accumulation of aquatic plants, which, like snake bodies, twisted around the ships, hindering their progress further west. With great difficulty, Columbus managed to cross the "water meadow". The travelers realized that they were in the kingdom of special algae, which keep air bubbles afloat, similar to clusters of small grapes. Sargaco is Portuguese for grape cluster. According to hydrobiologists, their total weight ranges from 4 to 11 million tons. So at first the algae, and then the sea, was named Sargasso.
Looking at the map, it can be seen in the vast expanses of the Atlantic Ocean, closer to the mainland of North America between 20 ° and 40 ° north latitude and 30 ° and 70 ° west longitude. The Sargasso Sea is shaped like a giant ellipse. This slowly rotating body of water lies between the Bermuda and Leeward Islands. In nature, this is a one-of-a-kind miracle of nature, the shores of which are large ocean currents: in the west and north - the Gulf Stream, originating in the Gulf of Mexico (more precisely, part of it - the North Atlantic Current), in the east - the Canary, in the south - the Passat. If the Gulf Stream is displaced by several tens of kilometers, the boundaries of the sea will also shift. We can say that the Sargasso Sea is an inveterate traveler, and its area is constantly changing.
This space of water saturated with floating algae is a huge area of calm, around which the movement is circular in a clockwise direction. In the sea itself, the currents are weak, and therefore algae accumulate here in large quantities. In addition, this area is also characterized by weak winds of variable directions, so that, having lost speed, a sailing ship may well get stuck here for many days and stand motionless under the mercilessly scorching sun.
There are many examples of this. So, in 1894 the schooner "Norwood" left the USA for Europe. A hurricane brought it into the Sargasso Sea. During the storm, the entire team was killed, and only a young henchman, Coca Tom-son, survived. He said that he saw there an old galleon, an eighteen-horse brig, and even a whole steamer. On a boat with a sail, Thomson got out of the "captivity". Eighteen years later, a similar story happened to the Italian three-masted sailing ship Herat. Its captain Vertolotto told about their misfortune: seven months of hopeless drifting in a vicious circle. “Herat” was also “delivered” to the Sargasso Sea by the strongest storm. The sailors saw only the frozen surface, completely covered with a carpet of seaweed. Branching tree trunks and wrecks of sunken ships, on which seabirds nested, protruded from this thicket, they said. The calm was complete, but the ship drifted slowly, constantly returning to its starting point. When food and water had almost dried up on board the Herat, a fresh breeze suddenly rose at night and the sailboat was carried out into clear waters.
The fact that there is a huge accumulation of algae in the middle of the ocean is phenomenal in its own way, but understandable. True, at first, scientists believed that algae were brought here by the current from the nearest shores, but it turned out that they are one of a kind and grow only here. The idea that algae on the surface of the sea were so thick that they could interfere with the movement of the ship was also completely wrong. The surface of the Sargasso Sea rather resembles the surface of a pond in autumn, when here and there you can see a floating leaf or a broken branch. But this oasis of still water carries all kinds of garbage that falls into the sea from land and from passing ships. And everything that gets into it lingers there for a long time. Here you can sometimes see wooden fragments of old ships, but the statement thatthat here the skeletons of all the ships that have crashed in the Atlantic over the past two or three centuries have gathered in a huge pile is absolutely false. As mentioned above, the reason that one cannot get out of the Sargasso Sea lies in the immobility of the waters.
The second phenomenon of the Sargasso Sea is its level. It is 1 - 2 meters higher than the surrounding ocean. This is due to the fact that oceanic waters are forced into the sea from all sides by currents, and its own waters first sink to a depth, and only then their outflow into the surrounding ocean goes. That is, the currents act as a kind of watersheds or dams, not allowing the surface waters of the Sargasso Sea to mix with the colder waters of the North Atlantic. In addition, the Sargasso Sea does not have cold currents coming out of it. This has two important consequences: its waters are warmer than those around them. Moreover, these warm waters penetrate to a considerable depth, deeper than it usually happens in the ocean. At a depth of 800-1000 m, the water temperature is + 10 ° С, while in other areas of the ocean at the same depth, the temperature is only + 5 ° С.
And secondly, the waters of the Sargasso Sea have very low productivity. The fact that a huge mass of algae is concentrated in this sea does not yet testify in favor of the biological wealth of its waters. They are low in nutrients, so there is no abundant plankton. The deep blue waters of this sea are typical oceanic desert. It is distinguished by weak currents, low precipitation, strong evaporations, slight winds, warm and very salty water, poor in oxygen and, as a consequence of all of the above, weak mixing of its various layers. All this creates a warm biological desert, almost devoid of plankton, which serves as the main food for fish.
Based on this, some experts “blame” the Sargasso Sea for all the troubles that occur in the Bermuda triangle. Australian oceanologist Richard Sylvester agrees with this. He says that this "conditional sea" got its own name only because millions of tons of algae have accumulated in it in the center of a huge whirlpool, which slowly rotates thanks to warm currents. It is this whirlpool that generates smaller eddies, which with the force of a terrifying "centrifuge" can pull into the abyss not only small ships, but also ocean tankers with a displacement of 20 thousand tons. According to Sylvester, these eddies give rise to mini-cyclones in the air, and they, in turn, suck in and send to the bottom aircraft flying nearby at low altitude. In support of his hypothesis, the oceanologist cites, for example,an entry in the logbook of June 1494, made by Christopher Columbus: "An unusual crater sucked three ships … in the absence of any storm or disturbance at sea."
Impressive, but most scientists and statistics disagree with him. According to the marine information service of the London insurance company "Lloyd", in the oceans every year, for various reasons, up to 200 large ships are killed - and least of all in the Bermuda Triangle. But the Sargasso Sea, even without the secrets of the Bermuda Triangle, is a unique natural phenomenon.