oceans unit test

Major Oceans

Atlantic, Indian, Pacific, Arctic, Southern.

Percent of Earth Covered with Water

70-75%.

Dead Zone

An area in the ocean where there is no oxygen and little to no marine life.

Causes of the Dead Zone

Nutrient pollution leading to hypoxia (low oxygen levels).

Factors Causing Ocean Layering

Temperature and salinity; warmer water is less dense than colder water, and saltier water is more dense than fresh water.

Things Affecting Ocean Currents

Temperature, salinity, wind, uneven heating, Coriolis effect, and basin shape.

Effect of Wind on Ocean Currents

Wind affects surface currents.

Effect of Density on Ocean Currents

Density affects deep-sea currents.

What Does Salinity Measure?

How salty and dense a body of water is.

Ways to Naturally Increase Salinity

Evaporation, freezing of seawater, and less freshwater input.

Ways to Naturally Decrease Salinity

Rainfall, melting ice, and river runoff.

Salinity and Density Relationship

Higher salinity and lower temperature increase water density, causing it to sink.

Ocean Temperature Layers

Surface layer (warmest), thermocline (rapid temperature drop), deep layer (coldest).

Gyre

A large circular ocean current caused by wind and Earth's rotation.

Upwelling

When deep, cold, nutrient-rich water rises to the surface.

Causes of Gyres

Wind patterns and the Coriolis effect, which is Earth's rotation.

Causes of Upwelling

Wind pushing surface water away, allowing deep water to rise.

Average Salinity of Sea Water

3.5% salt.

Waves

Movements of energy through water, usually caused by wind.

Wind Factors Influencing Waves

Wind speed, wind duration, and fetch.

Energy Movement Through Waves

Water moves in circular motions, transferring energy forward without moving much itself.

Wave Period

Time between two wave crests passing a point.

Wave Frequency

Number of waves passing a point per second.

Wave Length

Distance between two wave crests.

Wave Height

Vertical distance from crest to trough.

Shallow Water Waves

Waves in water shallower than half their wavelength.

Deep Water Waves

Waves in deep water without ocean floor influence.

Why Do Waves Break?

Waves break when they reach shallow water, slowing down at the bottom and causing the top to collapse.

Tides

The rise and fall of ocean water levels due to the gravity of the Moon and Sun.

Causes of Tides

The gravitational pull of the Moon and the Sun on the Earth.

Types of Tides

Spring tides (strongest, during alignment of Sun, Moon, Earth); Neap tides (weakest, when at right angles); Diurnal tides (one high, one low tide); Semidiurnal tides (two high, two low tides); Mixed tides (varying tide levels).

Light in the Ocean

Light gets darker and decreases as you descend into the ocean.

Pressure Changes in Ocean Depth

Pressure increases as you descend into the ocean.

Ocean Layers

Epipelagic (sunlight zone), Mesopelagic (twilight zone), Bathypelagic (midnight zone), Abyssopelagic (abyssal zone), Hadalpelagic (trenches).