Patterns of Circulation in the Ocean

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Ocean Current Noun

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[oh-shun kur-ent]

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Ocean Current

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A continuous, directed movement of seawater that flows like a river within the ocean, occurring at all depths.

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Example: This world map shows how large streams of ocean water, called currents, move around the globe, with red arrows for warm water and blue for cold.

Front

Surface Current Noun

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[sur-fis kur-ent]

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Surface Current

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A wind-driven current moving water horizontally in the upper few hundred meters of the ocean's surface layer.

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Example: This map shows the Gulf Stream, a major surface current in the Atlantic Ocean, as a red arrow moving warm water from the Gulf of Mexico towards Europe.

Front

Deep Current Noun

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[deep kur-ent]

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Deep Current

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A slow, density-driven current that moves large volumes of water in the deep ocean basins below the surface.

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Example: In polar seas, cold and salty water becomes dense, sinks, and flows along the ocean floor, creating a deep current.

Front

Coriolis Effect Noun

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[kor-ee-oh-lis uh-fekt]

Back

Coriolis Effect

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The apparent deflection of moving fluids, such as water and air, from a straight path due to Earth's rotation.

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Example: Because the Earth rotates, moving objects curve right in the Northern Hemisphere and left in the Southern Hemisphere, as shown by the arrows.

Front

Gyre Noun

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[jire]

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Gyre

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A large, circular system of rotating ocean currents that is formed by global winds and the Coriolis effect.

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Example: This map shows the five major ocean gyres, which are large, rotating systems of ocean currents driven by global winds.

Front

Gulf Stream Noun

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[guhlf streem]

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Gulf Stream

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A powerful, warm, and swift Atlantic ocean current that originates in the Gulf of Mexico and flows northward.

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Example: This map shows the Gulf Stream, a powerful warm ocean current, starting in the Gulf of Mexico (red) and flowing across the Atlantic Ocean.

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Density Noun

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[den-si-tee]

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Density

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The mass of a substance per unit volume; in seawater, it is primarily affected by temperature and salinity.

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Example: This triangle shows the formula for density (D), which is mass (M) divided by volume (V), a key mathematical relationship in science.

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Salinity Noun

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[suh-lin-i-tee]

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Salinity

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The measure of the total concentration of all dissolved salts present in a body of water, such as the ocean.

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Example: This world map uses color to show that ocean salinity (saltiness) is not the same everywhere, with some areas being much saltier than others.

Front

Thermohaline Circulation Noun

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[thur-mo-hay-leen sur-kyuh-lay-shun]

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Thermohaline Circulation

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Large-scale, deep-ocean water movement driven by global density gradients created by surface heat and freshwater fluxes.

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Example: This diagram shows how ocean water moves around the globe. Warm surface water cools and sinks, becoming a cold, salty deep current that flows back.

Front

AMOC (Atlantic Meridional Overturning Circulation) Noun

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[ay-mok]

Back

AMOC (Atlantic Meridional Overturning Circulation)

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The North Atlantic branch of the global thermohaline circulation, which transports significant amounts of heat from the tropics poleward.

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Example: This diagram shows the AMOC, a large ocean current. Warm surface water (red) flows north, cools, sinks, and returns south as cold deep water (blue).