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WONDERS OF NATURE
El Niño and the Humboldt Current. Nature miracle
Two currents in the Pacific Ocean are of particular interest. One of them, discovered and described by the great scientist whose name it bears, is unusual in the abundance of life that accompanies its stream. For more than one million years, this current has been carrying its cold waters from the "roaring forties" and "furious fifties" latitudes of the southern hemisphere to the equator, maintaining the route and speed of movement (15 miles per day) with the accuracy of a courier train. Another, with a sonorous Spanish name, you will not find on every map, and it does not appear every year. But if it appeared, newspapers and the scientific press of the whole world will write about it, and the consequences of its appearance will come back to haunt the rampant elements on all shores of the Great Ocean, and even farther ... This amazing current affects the climate of our entire planet. It is still not entirely clear why it is formed, and it is impossible to predict exactly when this will happen and what misfortunes it will entail. But the main reasons for the emergence of a strange current periodically appearing in the Pacific Ocean with the beautiful name El Niño are, in general, clear. And you need to look for them many thousands of kilometers from the equatorial belt of warm waters, where this phenomenon is recorded from time to time.
Far to the south, near the coast of Antarctica, there is the route of the most powerful circulation of ocean waters - the current of the West Winds. Rounding the icy continent, it crosses the three largest oceans of the Earth, while closing a huge ring 30 kilometers long. The width of the Antarctic Circumpolar Current, as it is also called, reaches 000 kilometers? and speed - more than two kilometers per hour. The amount of water it moves is estimated at 1300 million cubic meters per second. This is ten times more than the Gulf Stream carries at the outlet of the Gulf of Mexico! Without much difficulty, the course of the West Winds goes around the southern coasts of Africa, Australia and New Zealand, but near South America the mighty ocean current falls into a relatively narrow passage for it, formed by Tierra del Fuego and the Antarctic Peninsula. The Drake Strait located between them, although the widest in the world - 370 kilometers, of course, cannot accommodate the huge mass of water brought by the circular current. And then part of the cold waters of the current of the West Winds rushes to the north, to the equator, along the Pacific coast of South America. Sailors call this branch of the ocean river the Humboldt Current (or Peruvian). The Humboldt Current reaches Cape Blanco in Peru, where it meets the warm Equatorial Countercurrent. Both of these streams turn here to the west, forming the northern boundary of the South Equatorial Current.
In the zone of the meeting of cold and warm currents, a sharp temperature drop occurs: the waters of the Humboldt Current, cooler (plus 17 degrees), move under the waters that came from the equator and are heated to 24 degrees. The boundary between these water masses can be easily determined by the many eddies and whirlpools on the surface of the ocean. In addition, the characteristic "gurgling" is clearly audible - the sound of colliding streams, reminiscent of the sound of the surf. On its way from the Drake Passage to the equator, the Humboldt Current does not approach the coast of South America closer than XNUMX miles. There are few living organisms in its cold waters. But closer to the shore, the water literally teems with various forms of life: small crustaceans, jellyfish, algae, fish. Oceanologists did not immediately manage to understand the reasons for this difference. It turned out that the ocean off the South American coast is very deep. Already in the three-mile coastal zone, depths often reach a kilometer or more. The main winds here usually blow to the north and northwest, parallel to the coast, and drive surface water towards the equator. To replace it, bottom water rises from the depths, rich in phosphates - the main food of microorganisms and small algae (phytoplankton). The zones of the rise of cold deep waters are clearly identified by the muddy green patches of phytoplankton, which are rapidly developing in these places. From the plane, these swamp-colored water "islands" are clearly visible - they clearly stand out against the background of the bright blue waters of the Humboldt Current. The strip of the Pacific Ocean adjacent to the shores of South America is probably the region of the World Ocean richest in fish and other marine organisms. Moreover, on the way from Tierra del Fuego to Cape Cabo Blanco, the composition of marine life changes, and quite dramatically. This is due to an increase in the temperature of the surface waters of the Humboldt Current from 14 degrees near the Drake Passage to 17 degrees near the equator. Accordingly, in the south, the abundance of phytoplankton attracts many baleen whales, sperm whales, squids and cold-water fish (notothenia, icefish, etc.). And in the north, where the water is warmer, sardine, tuna, and especially anchovy are found in abundance. This small but tasty fish is incredibly prolific. It is estimated that the annual increase in the mass of anchovy in the ocean is equal to a quarter of the total world fish catch in a year. It is no coincidence that Peru is one of the three largest fishing powers in the world (along with Russia and Japan). Anchovies in coastal waters are enough not only for fishermen, but also for seabirds. Millions of gulls, cormorants and other birds nest on islands off the coasts of Peru and Chile. Since rains in these areas (near the Atacama Desert) are extremely rare, the birds build their nests in accumulations of their own droppings, the layer of which in bird colonies sometimes reaches a meter or more. By the way, dry bird droppings ("guano") is considered a very valuable fertilizer, and for many years Peru exported this product to Europe and the United States. But let's get back to the mysterious course of El Niño, which was discussed at the beginning of our story. Once every 7-10 years, disrupting the usual cycle of Pacific waters, a warm ocean current unexpectedly approaches the western coast of South America. This usually happens on New Year's Eve, when Catholics, predominantly among Hispanics, celebrate the Nativity of the Christ Child. Therefore, the current was given this name (El Niño - Spanish for "baby"). About what causes it, scientists are still arguing. One thing is clear: from time to time, the southeast trade winds, constantly blowing in the region of the fifth degree of southern latitude and forcing the warm waters of the Trade Wind to move west, for some reason stop blowing or lose a significant part of their strength. And then the giant masses of water from the west of the Pacific Ocean are sent to the shores of South America, forming, as it were, the "Southern Trade Wind Current in reverse." Indeed, due to the constant work of two powerful currents in the equatorial zone, the level of the western part of the ocean is 20 centimeters higher than in the east. And, if the ocean "piston" that pushed the water to the west is "turned off", it naturally tends to flow to where the ocean level is lower. And although the motives for the strange behavior of the trade winds are still being debated, one thing is clear - this is precisely the reason for the appearance of El Niño. Having reached the coasts of Peru and Ecuador, El Niño squeezes between the land and the Humboldt current, diverting it into the open ocean and driving it into the depths. The entire meteorological situation in the coastal zone is changing radically. And with climate change, the conditions for the existence of living organisms are also changing - first on the South American continent, and then in Southeast Asia. The following year, weather anomalies reach the northern regions, all the way to Europe. And each of us felt these "echoes of vagaries" of El Niño. For example, in the winter of 1982, it appeared again. Under his influence, the water temperature near the Galapagos Islands reached 30 degrees (5 degrees above normal). Sea lions swam away from the archipelago, leaving their rookeries, sea birds left their nests. The usually dry coastal regions of Ecuador and Peru have experienced heavy rains that have caused catastrophic flooding. Millions of seabirds that inhabited the "guan islands" died, caught in heavy rains in their nests, which turned into mud traps. Cormorants were especially affected, of which no more than ten percent survived. Off the coast of Peru, fish catches have fallen sharply. Anchovies followed the cold waters far into the ocean, and fishing boats, suitable only for coastal navigation, could not fish far from the coast. The entire economy of the country suffered enormous damage, which was further exacerbated by losses due to flooding. The absence of the trade winds caused an increase in atmospheric pressure over Indonesia and Northern Australia. Here, instead of the expected rainy season, there was still a drought, sowing of rice became impossible, and forest fires broke out in the jungle, covering large areas in Kalimantan, Sumatra and Malacca. The sharp warming of the waters in the east of the ocean has changed the usual picture of the alternation of low and high pressure zones over its water area. Powerful cyclones have caused unprecedented storms off the coast of Alaska and California. The list of weather anomalies and natural disasters associated with them could be continued for a long time. But even without that it is clear that nothing good can be expected from the "baby". The reappearance of El Niño in December 1996 confirmed this, causing new troubles in the Pacific region. This time, the effect of changing the pattern of winds and currents was even stronger than during his previous appearances. Huge damage was again suffered by the forests of Indonesia and Malaysia. The fires also destroyed part of the plantations, and the smoke that covered the sky sometimes prevented the townspeople from breathing normally. It rained for the first time in fifteen years in the Atacama Desert, and mud avalanches descended from the slopes of the Andes, destroying entire villages. A year later, a thaw rainy winter and unusual summer cold marked the weather in Europe and North America. The last echoes of El Niño made themselves known to the Europeans, including us, in the spring and summer of 1999. Many residents of Central Russia probably remember hot April, snowy May and scorching thirty-degree heat June-July that year. Most of us most likely won't have to swim in the Pacific Ocean. But even when looking at a map with red and blue arrows of sea currents, it is sometimes worth thinking about how small our world is, how inextricably linked on our small planet are seemingly distant places, phenomena and processes, and how in the most unexpected way natural anomalies arising thousands of kilometers away, similar to the El Niño current, respond to our fate. Author: B.Wagner
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