Oceans - Life in Water (Ch 03)

A set of practice flashcards covering key concepts from the Oceans – Life in Water notes (Ch 03).

What percentage of Earth's surface is covered by the oceans?

About 70.8%.

Which is the largest ocean basin and what is its approximate area and average depth?

The Pacific Ocean; about 180 million square kilometers in area with an average depth of about 4,000 meters.

Which is the second largest ocean basin and what is its approximate area and average depth?

The Atlantic Ocean; about 106 million square kilometers in area with an average depth of about 3,900 meters.

Which ocean covers just under 75 million km2 and has an average depth around 3,741 meters?

The Indian Ocean.

Which ocean surrounds Antarctica and is sometimes called the Antarctic Ocean, with area over 21 million km2?

The Southern Ocean (Antarctic Ocean).

Which is the smallest ocean, roughly 14 million square kilometers in area?

The Arctic Ocean.

What are the underwater features consisting of mountains and trenches that study the deep ocean floor?

Undersea mountains and trenches.

How deep is the Marianas Trench?

Over 10,000 meters (about 6 miles) deep.

What is the Littoral Zone?

The intertidal zone, a shallow shoreline area.

What is the Neritic Zone and its typical depth near the coast?

Extends from the coast to the margin of the continental shelf; about 200 meters deep.

What is the Benthic Zone?

Habitat on the bottom of the ocean.

What does the Oceanic Zone 'Beyond the continental shelf' refer to?

The part of the ocean beyond the continental shelf.

What happens to water temperature and density when solar energy warms the water?

Warm water becomes less dense and floats on top of cooler water; kinetic energy increases.

Define the thermocline and its typical rate of temperature change with depth.

A depth zone where temperature changes rapidly with depth, typically about 1°C per meter, creating thermal stratification.

How does evaporation and atmospheric transport affect salinity among oceans?

Evaporation from one ocean and transport of water via clouds returns water to others, making the Atlantic saltier and the Indian and Pacific less saline.

What drives Thermo-Haline circulation?

The movement of water driven by differences in temperature and salinity, including sinking of cooled, saline water.

What are gyres in the ocean?

Wind-driven surface current systems that form large circular patterns.

Name the five major subtropical gyres.

North Pacific Subtropical Gyre; South Pacific Subtropical Gyre; North Atlantic Subtropical Gyre; South Atlantic Subtropical Gyre; Indian Ocean Subtropical Gyre.

How does wind influence ocean currents in relation to the Coriolis effect in the Northern and Southern Hemispheres?

Currents deflect to the right of the wind in the Northern Hemisphere and to the left in the Southern Hemisphere due to the Coriolis effect.

Does the Coriolis force apply at the Equator?

No; the Coriolis force is zero at the Equator.

What factors contribute to high productivity in reefs and kelp beds?

Sufficient light for photosynthesis, currents delivering oxygen and nutrients and removing waste, and flushing action.

Where are kelp forests typically found and how tall can they grow?

Beyond the intertidal zone in temperate latitudes; may reach over 40 meters tall; found where the bottom is solid.

What are Fringing Reefs?

Reefs that grow directly from the shore of continents.

What are Barrier Reefs?

Extensive linear reef complexes that parallel a shore, separated by a lagoon.

What are Atolls?

Roughly circular oceanic reef systems built around a submerged island, surrounding a large central lagoon.