Water. Oceans. Currents

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Water in the oceans:

Water in the oceans Lecture No. 14.

Water on Earth:

Water on Earth Water is vital (жизненно необходимый) for life. All living organisms consist of 2/3 (two thirds) of water. Flora and fauna depend on (зависят от) water. Surface water: 97,5% salt water, 2,5% fresh water. Water covers 71% of the Earth’s surface. Water dissolves ( растворяет) substances (вещества) and transports them between land and sea.

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Weather, temperature and climate depend on water. Water shapes ( придает форму) the planet.

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An ocean is a continuous expanse of seawater. A sea is a landlocked water basin. Seawater consists of 97% of water and 3% of mineral salts, like sodium chloride (table salt).


Oceans There are 5 oceans: The Pacific ocean ( Тихий) The Atlantic ocean (Атлантический) The Indian ocean (Индийский) The Southern Ocean (Южный) The Arctic ocean (Северный Ледовитый)

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The Southern ocean is beyond 50-55 degrees southern latitude.

Ocean currents:

Ocean currents An ocean current is a continuous, directed movement of ocean water generated by Waves (волны) W ind Coriolis effect T emperature Salinity (соленость, минерализация) Tides ( приливы и отливы)

World currents:

World currents

Types of ocean currents:

Types of ocean currents There are two types of ocean currents: Deep ocean currents ( глубинные течения) Surface currents (поверхностные течения) Constant ( постоянный) Seasonal ( сезонный) Ocean currents are measured in Sverdrup (Sv) 1Sv = 1,000,000 m 3 per second.

Surface currents:

Surface currents Made by winds: the Ekman spiral effect makes the water flow at the same angle as the dominant wind Develop spirals

Ekman spiral effect. 1:Wind 2:force from above 3:Effective direction of the current 4: Coriolis effect:

Ekman spiral effect. 1 :Wind 2 :force from above 3 :Effective direction of the current 4 : Coriolis effect 1 2 3 4

Deep ocean currents:

Deep ocean currents Made by density ( плотность) : Cold or salty water is more dense and sinks, and temperature, gravity ( сила тяжести) Studied by Argo, underwater robots

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Deep ocean currents make the conveyor belt. One circuit can take 1000 years to complete.

Upwelling and downwelling:

Upwelling and downwelling Coriolis force causes water to move to the right in the North and to the left in the South. Upwelling brings cold water with rich marine food to the surface. Downwelling causes floods.


Examples Ocean currents determine the climate of the Earth . the most famous example is the Gulf Stream , which makes northwest Europe temperate . Another example is the California Current which makes the Hawaiian Islands , cooler than other places in the tropical latitudes.

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