You will learn from this article what importance currents have for the Earth’s climate.
What is the significance of ocean currents?
Ocean currents are the movement of water directed horizontally relative to the surface of the ocean.
In general, the ocean can be compared to a large heat engine, which uses solar energy instead of fuel. She sets it in motion. The machine creates uninterrupted water exchange between the deep and surface layers of the ocean, which provide all living things in it with dissolved oxygen and have a beneficial effect on the life of marine life.
Ocean currents play an important role in the redistribution of solar heat on our planet. Everything is very simple: cold currents lower the ambient air temperature, and warm currents, on the contrary, increase it. Thus, the currents of the World Ocean have a huge influence on the coastal climate of continental zones. Just like air masses, they transfer cold and heat, changing climatic temperatures.
In addition, ocean currents influence the redistribution of precipitation on land. Those territories that are washed by warm waters are always characterized by a humid climate, and those that are washed by cold waters are characterized by a dry climate without rain, where fogs act as natural humidifiers.
Under the influence of currents and waves, ocean water is constantly mixed. As a result, cold water gradually sinks to the bottom, and warm water slowly rises to the surface. When warm and cold water mixes in deep depressions, it becomes saturated with gases and various substances. Then ocean currents distribute it throughout the water surface and affect the processes of atmospheric circulation, coastal erosion, the enrichment of oxygen in water, the movement of ice and the movement of plankton, the distribution of marine animals and fish.
Speaking about the fauna of the ocean, the importance of ocean currents in their distribution also plays an important role. They carry plankton with their waters, and large marine animals migrate behind them. It is worth noting that when a warm current meets a cold one, ascending currents of water are created, which lift rich and nutritious salts from the depths. In such places, plankton develops and reproduces at tremendous speed. Such places are fishing grounds rich in marine animals and fish.
Ocean currents also play an important role in navigation: sailing ships and shipping companies use them to reduce the time of sea travel and to reduce fuel consumption and delivery.
It happens that a cold current turns into a warm one. This leads to an increase in the average ambient temperature by several degrees and torrential tropical downpours. They have a detrimental effect on fish: small ones die, and large ones go to other places.
We hope that from this article you learned how important ocean currents are.
Variety of currents. Currents in the seas and oceans are as important a type of water movement as waves.
Current is the movement of water in a horizontal direction.
Currents carry huge masses of water over long distances. Their length can reach several thousand kilometers, width - tens and even hundreds of kilometers, thickness - several kilometers.
One of the largest currents is the Gulf Stream (Fig. 129). It carries more water than all the rivers on our planet combined.
Rice. 129. Main sea currents
How are warm and cold surface currents indicated on a map? Find the largest warm and cold currents in the picture.
Rice. 130. Diversity of ocean currents
Ocean currents vary in temperature, depth, and duration of existence (Fig. 130).
A current whose temperature is higher than the temperature of the surrounding water is called warm. Cold - the temperature of which is lower than the temperature of the surrounding water. If we compare the temperature of the water of the currents themselves, then the water of a cold current in the tropics can be warmer than the water of a warm current in high latitudes.
Causes of currents. The main reason for the appearance of surface currents is wind. Touching the water surface, it carries water with it. Under the influence of stable westerly winds, the most powerful Western Wind current in the World Ocean arises, forming a ring around Antarctica.
The direction of currents is also influenced by the position of the continents and the outlines of their coasts. The land becomes an obstacle, forcing the current to turn and head along the coasts.
In the depths of the seas and oceans, currents are formed due to differences in the density of water. More dense waters move towards less dense ones, creating powerful water flows at depth. Information about underwater currents is important for fishing and submarine movement.
The meaning of currents. Ocean currents influence the climate and nature of the Earth. They redistribute heat and cold between latitudes. Warm currents bring heat from tropical latitudes to temperate and arctic latitudes. Cold currents return cold water to the equator. At the same time, currents strongly influence the climate of the coastal areas of the continents.
Think about how warm and cold ocean currents affect the nature of coasts.
Thanks to currents in the oceans and seas, not only heat is redistributed, but also dissolved nutrients and gases. Living organisms receive more opportunities for development. With the help of currents, plants and animals move and colonize new territories. Currents can help or hinder navigation, so mariners and fishermen must be aware of their direction and speed.
Questions and tasks
- What is current?
- Which current can be considered warm? which one is cold?
- Name the main reasons for the formation of currents.
- What is the significance of currents for the climate of the Earth and the plants and animals of the ocean?
The direction of currents is influenced by the force of the Earth's rotation: in the Northern Hemisphere, currents move to the right, in the Southern Hemisphere, to the left.
A current is called warm if its temperature is warmer than the temperature of the surrounding waters; otherwise, the current is called cold.
Density currents are caused by pressure differences, which are caused by the uneven distribution of seawater density. Density currents are formed in the deep layers of seas and oceans. A striking example of density currents is the warm Gulf Stream.
Wind currents are formed under the influence of winds, as a result of the frictional forces of water and air, turbulent viscosity, pressure gradient, deflecting force of the Earth's rotation and some other factors. Wind currents are always surface currents: northern and southern trade winds, the current of the western winds, the inter-trade winds of the Pacific and Atlantic.
1) The Gulf Stream is a warm sea current in the Atlantic Ocean. In a broad sense, the Gulf Stream is a system of warm currents in the North Atlantic Ocean from Florida to the Scandinavian Peninsula, Spitsbergen, the Barents Sea and the Arctic Ocean.
Thanks to the Gulf Stream, the countries of Europe adjacent to the Atlantic Ocean have a milder climate than other regions at the same latitude: masses of warm water heat the air above them, which is carried by westerly winds to Europe. Deviations of air temperature from the average latitude values in January reach 15-20 °C in Norway, and more than 11 °C in Murmansk.
2) The Peruvian Current is a cold surface current in the Pacific Ocean. It moves from south to north between 4° and 45° south latitude along the western coasts of Peru and Chile.
3) The Canary Current is a cold and, subsequently, moderately warm sea current in the northeastern part of the Atlantic Ocean. Directed from north to south along the Iberian Peninsula and North-West Africa as a branch of the North Atlantic Current.
4) The Labrador Current is a cold sea current in the Atlantic Ocean, flowing between the coast of Canada and Greenland and rushing south from the Baffin Sea to the Newfoundland Bank. There it meets the Gulf Stream.
5) The North Atlantic Current is a powerful warm ocean current that is the northeastern continuation of the Gulf Stream. Starts at the Great Bank of Newfoundland. West of Ireland the current divides into two parts. One branch (the Canary Current) goes south and the other goes north along the coast of northwestern Europe. The current is believed to have a significant influence on the climate in Europe.
6) The Cold California Current emerges from the North Pacific Current, moves along the coast of California from northwest to southeast, and merges in the south with the North Trade Wind Current.
7) Kuroshio, sometimes the Japan Current, is a warm current off the southern and eastern coasts of Japan in the Pacific Ocean.
8) The Kuril Current or Oyashio is a cold current in the northwest Pacific Ocean, which originates in the waters of the Arctic Ocean. In the south, near the Japanese Islands, it merges with Kuroshio. It flows along Kamchatka, the Kuril Islands and the Japanese islands.
9) The North Pacific Current is a warm ocean current in the North Pacific Ocean. It is formed as a result of the merger of the Kuril Current and the Kuroshio Current. Moving from the Japanese islands to the shores of North America.
10) The Brazil Current is a warm current of the Atlantic Ocean off the eastern coast of South America, directed to the southwest.
P.S. To understand where the different currents are, study a set of maps. It will also be useful to read this article
What is the significance of ocean currents?
Answers:
Ocean currents can transport marine fish. Ocean currents are designed to filter sea water. Redistribute heat on the planet, forming climate and precipitation.
An important regularity of currents in the open ocean is that their direction does not coincide with the direction of the wind. It deviates to the right in the Northern Hemisphere and to the left in the Southern Hemisphere from the wind direction by an angle of up to 45°. Observations show that in real conditions the deviation at all latitudes is slightly less than 45°. Each underlying layer continues to deviate to the right (left) from the direction of movement of the overlying layer. At the same time, the flow speed decreases. Numerous measurements have shown that the currents end at depths not exceeding 300 meters. The significance of ocean currents lies primarily in the redistribution of solar heat on Earth: warm currents contribute to an increase in temperature, and cold currents lower it. Currents have a huge impact on the distribution of precipitation on land. Territories washed by warm waters always have a humid climate, and cold ones always have a dry climate; in the latter case, there is no rain, only fogs have a moisturizing value. Living organisms are also transported with currents. This primarily applies to plankton, followed by large animals. When warm currents meet cold ones, upward currents of water are formed. They raise deep water rich in nutritious salts. This water favors the development of plankton, fish and marine animals. Such places are important fishing grounds. The study of sea currents is carried out both in the coastal zones of the seas and oceans, and in the open sea by special sea expeditions
1. Make a classification of water movements in the ocean based on the reason for their occurrence. Fill out the diagram
2. How does a tsunami differ from storm wind waves?
Tsunamis are waves that arise as a result of seaquakes, and wind waves are the result of wind activity. A tsunami is a forward movement of water, and wind waves are oscillatory.
3. What is the significance of ocean currents?
Ocean currents influence the climate of the territory. Cold currents bring cooling and dryness, and warm currents bring warming and precipitation. Currents also transport organic substances, contributing to their distribution throughout the oceans.
4. Using the ocean map in the atlas, plot on the contour map:
a) places of the highest tides - green
b) warm currents Gulf Stream, North Atlantic, Kuroshio, South Trade Wind, North Trade Wind, Brazilian and Guiana - in red
c) cold currents Peruvian, Labrador, Canary, Western Winds, Benguela - in blue
Label the currents with the initial letters of their names
5. Imagine that an accident occurred on an oil tanker near the equator off the eastern coast of South America. The accident resulted in an oil spill. In what areas of the ocean can traces of this accident be found? To answer, use the ocean map in the atlas.
Traces of this accident can be found in any part of the ocean, because currents will carry the oil. For example, the Northern Trade Wind Current will transport oil to the Gulf Stream, then in turn to the North Atlantic, then to the Canary or Norwegian. The southern trade wind current will carry oil into the Brazil Current, then into the Westerly Winds and then across the South Pacific, Atlantic and Indian Oceans.
