Freshwater and Saltwater Systems: The Oceans

Vocabulary flashcards covering ocean water composition, ocean basin geology, waves, tides, currents, and their effects on climate based on Topic 4 of the lecture notes.

Controlled variable

The variable(s) you keep the same in an experiment.

Manipulated variable

The variable that you change in an experiment.

Responding variable

What happened as a result of the experiment.

Ocean water composition

A mixture containing $96.5\%$ water and $3.5\%$ salts.

Mineral percentages in salt water

Contains chloride ($55\%$), sodium ($30.6\%$), sulphate ($7.7\%$), magnesium ($3.7\%$), calcium ($1.2\%$), potassium ($1.1\%$), and others ($0.7\%$).

Salt origin

Most started in rocks on land, where rivers and groundwater dissolve soluble elements as they flow over them.

Volcanic salt sources

Molten lava and gases on the seafloor add chlorine and sulphur, while land eruptions circulate gases in the atmosphere that enter the ocean via rain or surface dissolution.

Ocean basins

Geological features beneath sea level consisting of mountain ranges, steep valleys, and vast plains shaped by tectonic plate movements.

Ocean trenches

The deepest part of the ocean floor, created when tectonic plates converge or come together.

Ocean ridges

Underwater mountain ranges formed when tectonic plates pull apart or diverge from each other.

Continental shelf

The submerged part of the continent that extends from the coast to the edge of the ocean basin.

Continental slope

A feature that plunges at a steep angle from the edge of the continental shelf to the sea floor.

Abyssal plains

Wide, open, and remarkably flat features of the deep sea floor located between high mountain ranges and deep trenches.

Mid-Atlantic Ridge

A large mountain range in the Atlantic ocean caused by the pulling apart of tectonic plates.

Waves

Water movements whose height depends on wind speed, duration, and distance, though they can also be caused by earthquakes, volcanic eruptions, or landslides.

Beaches

Deposits of sediment that run along the shoreline, often formed where the slope is gentle and waters are calm.

Seawalls and breakwaters

Concrete and steel barriers designed to slow down the speed and force of ocean waves to reduce erosion.

Tides

The daily rise and fall of the Earth’s water along the shore caused mainly by the pull of the Moon’s gravity.

Spring tides

The largest tidal movements occurring when Earth, Moon, and Sun are in a line, resulting in extra high and extra low tides.

Neap tides

The smallest tidal movements occurring when the Sun and Moon are at right angles, resulting in little difference between high and low tides.

Tidal range

The difference in level between a high tide and a low tide.

Ocean current

A massive river within the ocean that flows in one direction and connects one place with another.

Surface currents

Currents driven by winds that mostly flow in the top $100-200\,\text{m}$ of water.

Coriolis Deflection

The bending of moving wind and water currents caused by the rotation of the Earth from west to east.

Warm currents

Currents that begin near the equator where the Sun’s heat is most intense.

Gulf Stream

A warm water current starting in the Caribbean Sea that flows north along North America and northeast across the Atlantic, making Britain's climate milder.

Labrador Current

A cold current that flows from Baffin Island towards Newfoundland.

Heat capacity

A property of water where it takes a long time to heat up or cool down, leading to more temperate climates by the ocean.

El Nino

A warmer than normal Pacific Ocean weather pattern resulting in warm, dry winters in the east.

La Nina

A cooler than normal Pacific Ocean weather pattern resulting in cool, wet conditions in the west.