8 The Oceans Free Online FlashCards

What is the continental shelf?

The continental shelf is the shallow, submerged edge of a continent.

How do plate motions reshape ocean basins?

Seafloor spreading at mid-ocean ridges creates new crust, while subduction recycles old crust at convergent boundaries.

What is the average salinity of ocean water?

Average ocean salinity is about 35 parts per thousand, or roughly 3.5 percent by mass.

Which seawater tends to sink: cold, salty water or warm, less-salty water?

Cold, salty water is generally denser than warm, less-salty water, so it tends to sink.

What drives and steers surface currents?

Surface currents are driven mainly by winds; Earth’s rotation deflects moving water, and continents steer currents.

What is fetch, and how does it affect wind-driven waves?

Fetch is the distance wind blows across open water; wave size depends partly on fetch, wind speed, and how long the wind blows.

What alignment produces a spring tide?

A spring tide has a larger tidal range because the Sun, Moon, and Earth are approximately aligned, reinforcing their tidal effects.

How does the ocean’s heat storage influence climate?

By storing and redistributing substantial heat from warmer toward cooler regions, the ocean moderates climate, especially near coasts.

What is an ocean trench?

An ocean trench is a deep, narrow seafloor depression commonly associated with subduction.

How do evaporation and freshwater inputs affect salinity?

Evaporation tends to raise salinity; rainfall, river inflow, and melting ice tend to lower it.

Which way do major ocean gyres generally rotate in each hemisphere?

Major gyres generally rotate clockwise in the Northern Hemisphere and counterclockwise in the Southern Hemisphere.

What does upwelling bring toward the ocean surface?

Upwelling brings colder, often nutrient-rich water toward the ocean surface.