Ocean Relief, Ocean Movements, and Marine Resources

Comprehensive vocabulary flashcards covering ocean floor divisions, oceanic relief features, wave characteristics, tidal patterns, ocean currents, marine resources, and coastal livelihood challenges.

Continental Shelf

The gently sloping submerged extension of a continent extending from the coastline to the shelf break, typically at a depth of about $200\text{ metres}$.

Continental Slope

The steep slope beginning at the shelf break that descends to the deep ocean floor and marks the true boundary between continental and oceanic crust.

Submarine Canyons

Deep, steep-sided valleys cutting into the continental slope, formed by underwater landslides or river action during periods of lower sea levels.

Continental Rise

A gently sloping feature located at the base of the continental slope, formed by sediments accumulated by turbidity currents.

Turbidity Currents

Underwater landslides of sediment-laden water that flow down the continental slope to deposit the sediments of the continental rise.

Abyssal Plains

Vast, extremely flat areas of the deep ocean floor found at depths between $3,000$ and $6,000\text{ metres}$, formed by fine sediment deposition over millions of years.

Mid-Oceanic Ridges

Long underwater mountain chains formed by volcanic activity along divergent plate boundaries where magma rises and cools.

Sea-Floor Spreading

The process occurring along mid-ocean ridges where magma rises from beneath the Earth's crust, cools, and forms new oceanic crust.

Ocean Trenches

Long, narrow, and extremely deep depressions located at convergent plate boundaries where one tectonic plate is forced beneath another.

Subduction

The tectonic process at convergent plate boundaries in which one plate is forced beneath another down into the Earth's mantle.

Mariana Trench

The deepest known part of the ocean, situated in the Pacific Ocean and reaching a depth of approximately $11,000\text{ metres}$.

Seamounts

Underwater volcanic mountains that rise from the ocean floor but do not reach the surface of the water.

Guyots

Flat-topped seamounts that were once volcanic islands eroded by wave action and later submerged due to crustal sinking.

Oceanic Plateaus

Large, elevated, and broad flat areas on the ocean floor formed by extensive volcanic eruptions, such as the Kerguelen Plateau.

Coral Reefs

Organic structures formed by coral polyps accumulating skeletons in warm, shallow tropical waters.

Fringing Reefs

A class of coral reefs that are attached directly to the coastline or shore.

Barrier Reefs

Coral reefs that are separated from the main shoreline or landmass by a lagoon.

Atolls

Ring-shaped coral reefs that surround a central body of water called a lagoon.

Waves

Rhythmic up-and-down movements of ocean water caused primarily by wind blowing across the water surface, transferring energy rather than large masses of water.

Crest

The highest elevated point of an ocean wave.

Trough

The lowest depression point between two successive ocean waves.

Wavelength

The horizontal distance between two successive crests or two successive troughs of a wave.

Wave Height

The vertical distance measured between the crest and the trough of a wave.

Wave Period

The time required for two successive wave crests to pass a stationary reference point.

Wave Frequency

The number of wave crests that pass a given point in each second.

Swell Waves

Long, regular ocean waves that travel great distances across the ocean from where they were originally generated.

Tsunamis

Massive ocean waves generated by underwater earthquakes, volcanic eruptions, or submarine landslides.

Storm Surges

Abnormal increases in sea level along coasts during storms, driven by intense winds and low atmospheric pressure.

Tides

The regular rise and fall of sea levels caused primarily by the gravitational pull of the Moon and, to a lesser extent, the Sun, along with centrifugal forces.

Spring Tides

Tides that produce the greatest tidal range, occurring during the full moon and new moon when the Sun, Moon, and Earth are aligned.

Neap Tides

Tides that produce the smallest tidal range, occurring during the first and third quarter phases of the Moon when the Sun and Moon form a right angle with the Earth.

Semi-Diurnal Tides

A tidal pattern featuring two high tides and two low tides of approximately equal height every day.

Diurnal Tides

A tidal pattern consisting of one high tide and one low tide per day.

Mixed Tides

A tidal pattern characterized by two high tides and two low tides each day that differ significantly in height.

Ocean Currents

Large, continuous streams of water flowing in definite directions through the ocean, involving the actual movement of water masses.

Coriolis Effect

The deflection of moving ocean currents and air masses caused by Earth's rotation, turning them to the right in the Northern Hemisphere and to the left in the Southern Hemisphere.

Surface Currents

Wind-driven ocean currents that circulate within the upper $400\text{ metres}$ of the ocean.

Deep Water Currents

Ocean currents driven by thermohaline circulation, where differences in temperature and salinity cause dense, cold water to sink in polar regions and flow toward the equator.

Marine Biological Resources

All living organisms obtained from the ocean, including fish, crustaceans, mollusks, marine mammals, seaweeds, and plankton.

Aquaculture

The cultivation and farming of fish, shellfish, seaweeds, and other aquatic organisms in controlled marine environments for food or commercial purposes.

Polymetallic Nodules

Small, round mineral deposits found on the deep ocean floor that contain valuable metals including manganese, nickel, copper, and cobalt.

Ocean Thermal Energy Conversion (OTEC)

A renewable marine energy technology that produces electricity by exploiting temperature differences between warm surface seawater and cold deep ocean water.

Coral Bleaching

The whitening and damage to coral structures caused by rising sea temperatures, which degrades coral reef ecosystems and fish breeding grounds.

Eutrophication

A process caused by agricultural runoff and industrial effluents enriched with nutrients that depletes dissolved oxygen levels in water, resulting in fish mortality.

Mangrove Plantation

A coastal afforestation practice that protects shorelines from erosion, storm surges, and cyclone damage.

Offshore

Located or happening in the sea away from the land or coastline.