Module 11 (Ocean Currents)

What drives ocean currents?

A combination of factors: temperature, gravity, prevailing winds, the Coriolis effect, salinity, and the location of continents.

Define gyre.

A large-scale pattern of water circulation that moves clockwise in the Northern Hemisphere and counterclockwise in the Southern Hemisphere.

What is upwelling?

The upward movement of ocean water toward the surface as a result of diverging currents, bringing nutrients from the ocean floor.

What does thermohaline circulation drive?

The mixing of surface water and deep water, primarily driven by cold salty ocean water sinking near the poles.

What is the El Nino-Southern Oscillation (ENSO)?

A reversal of wind and water currents in the South Pacific, occurring every 3-7 years.

What are normal conditions for ocean currents in the eastern and western Pacific?

East to west wind direction with cold water in the western Pacific and warm water in the eastern Pacific.

What changes occur during El Nino conditions?

Wind direction shifts to west to east, with low precipitation in the western Pacific and warm water in both the eastern and western Pacific.

What are the effects of upwelling?

It supports high productivity in upwelling zones, which then supports large fish populations.

What is the Coriolis effect?

The apparent deflection of moving objects, such as wind and ocean currents, caused by the rotation of the Earth.

What are surface currents?

Ocean currents that flow horizontally near the surface of the ocean, primarily driven by wind.

Define thermocline.

A layer in the ocean where temperature changes rapidly with depth, separating the warmer surface water from the colder deep water.

What is a deep ocean current?

A current that flows beneath the surface of the ocean, driven by differences in water density caused by temperature and salinity.

What is the role of ocean currents in climate?

Ocean currents regulate climate by redistributing heat around the planet, influencing weather patterns and temperatures.

What is upwelling's effect on marine ecosystems?

It enhances nutrient availability, leading to higher productivity and biodiversity in marine ecosystems.

What are the consequences of El Nino events?

They can lead to extreme weather patterns globally, including droughts, floods, and shifts in marine biodiversity.

What is the role of wind in ocean currents?

Wind helps to generate surface currents by transferring energy to the water's surface.

How do ocean currents affect marine life?

Ocean currents affect the distribution of nutrients and temperature, influencing where marine life thrives.

What factors influence the density of ocean water?

The density is influenced by temperature and salinity; colder and saltier water is denser.

What is the Gulf Stream?

A major Atlantic Ocean current that originates in the Gulf of Mexico and flows northeast towards Europe, influencing climates.

What is thermohaline circulation?

A global ocean circulation pattern driven by differences in water temperature and salinity.

What phenomenon occurs due to the Coriolis effect?

The deflection of ocean currents and wind patterns to the right in the Northern Hemisphere and to the left in the Southern Hemisphere.

What is coastal upwelling?

Localized upwelling that occurs off the coasts due to wind patterns that push surface waters away from shore.

What is the primary cause of the El Niño phenomenon?

The warming of the central and eastern tropical Pacific Ocean, disrupting normal wind and current patterns.

What are subtropical gyres?

Large systems of circulating ocean currents found in subtropical regions, typically characterized by warm, stable waters.

How do ocean currents impact weather patterns?

They influence temperature and moisture content in the atmosphere, affecting regional and global weather patterns.