Oceanography

Which planet's moon is believed to have an ocean of liquid water beneath its icy surface?

Jupiter's moon Europa.

What evidence suggests that Saturn's moon Enceladus has a subsurface ocean?

Geysers of water vapor and ice containing salt and mineral grains.

Which moon of Jupiter has a spidery network of dark cracks suggesting an ocean beneath its surface?

Europa.

Which moon of Saturn is reported to have a liquid ocean beneath its icy surface?

Dione.

What is the significance of the hydrothermal activity found on Enceladus?

It resembles underwater hot springs on Earth, which may have been key to the development of life.

Which moon of Saturn hosts small seas of liquid hydrocarbons?

Titan.

Which ocean is the largest and deepest on Earth?

Pacific Ocean.

What percentage of Earth's water is contained in the oceans?

97.2%

Which ocean is named after a Titan in Greek mythology?

Atlantic Ocean.

What is the main characteristic that distinguishes a sea from an ocean?

A sea is smaller and shallower than an ocean.

What is the deepest part of the world's oceans?

The Challenger Deep region of the Mariana Trench.

Which ocean is mostly located in the Southern Hemisphere?

Indian Ocean.

Which ocean is defined by the Antarctic Convergence?

Southern Ocean.

What is the average depth of the world's oceans?

3682 meters (12,080 feet).

How do the oceans influence global climate and weather?

Through currents and heating/cooling mechanisms.

What period is known as Europe's Age of Discovery?

The 30-year period from 1492 to 1522.

Who was the first European to round the southern tip of Africa?

Bartholomeu Diaz (1486).

Which explorer established a new eastern trade route to Asia by sailing around Africa?

Vasco da Gama (1498).

Which explorer is credited with the first circumnavigation of the globe?

Ferdinand Magellan (completed by Juan Sebastian del Caño).

Which explorer first sighted the Pacific Ocean by crossing the Isthmus of Panama?

Vasco Núñez de Balboa.

What was the outcome of the English defeating the Spanish Armada in 1588?

The English became the dominant world power.

Which English navigator mapped many unknown islands and made three voyages?

Captain James Cook.

What disease did Captain Cook help prevent, and how?

Scurvy, by including sauerkraut (Vitamin C) in the diet.

What is oceanography?

The scientific study of all aspects of the marine environment.

What are the four main disciplines of oceanography?

Geological, Chemical, Physical, Biological.

Why is oceanography considered an interdisciplinary science?

Because it examines multiple scientific disciplines as they apply to the oceans.

What is a hypothesis?

A tentative, testable statement about observed phenomena.

What is a theory?

A well‑substantiated explanation incorporating facts, laws, and tested hypotheses.

What is peer review?

The process where experts evaluate scientific work for quality and accuracy.

What are observations?

Initial sensory detections that lead to data and hypotheses.

What is the Nebular Hypothesis?

The theory that the solar system formed from a cloud of gas and dust.

What is density stratification?

The separation of materials by density when Earth was molten.

What is the lithosphere?

Earth's cool, rigid outer layer (crust + upper mantle).

What is the asthenosphere?

A hot, plastic layer beneath the lithosphere that can flow.

What is isostatic adjustment?

Vertical movement of the crust due to buoyancy.

What is oceanic crust like?

Denser, thinner, basaltic.

What is continental crust like?

Less dense, thicker, granitic.

What is outgassing?

The release of gases from Earth's interior forming the second atmosphere.

What was the Great Oxidation Event?

The rise of atmospheric oxygen ~2.45 billion years ago.

What did Stanley Miller's experiment show?

Organic molecules can form from inorganic components under early Earth conditions.

What are autotrophs?

Organisms that make their own food.

What are heterotrophs?

Organisms that rely on external organic compounds for food.

What is photosynthesis?

A process that captures energy and releases oxygen.

What is respiration?

A process that uses oxygen and releases energy.

What is radiometric age dating?

Using radioactive decay to determine rock age.

How old is Earth?

4.6 billion years.

What is a half-life?

Time required for half of radioactive atoms to decay.

Who proposed continental drift?

Alfred Wegener.

What was Wegener's book called?

The Origins of Continents and Oceans.

What rock evidence supported continental drift?

Similar rock sequences on both sides of the Atlantic.

What mechanism did Wegener propose for continental movement?

Gravitational and tidal forces.

What glacial evidence supported continental drift?

Glacial activity in now‑tropical regions.

What did Wegener propose about leading continental edges?

They deformed into mountain ridges due to sea‑floor drag.

What fossil evidence supported continental drift?

Mesosaurus fossils in South America and Africa.

Why was Wegener's hypothesis rejected?

Flawed mechanism for continental movement.

What was the ancient supercontinent called?

Pangaea.

What climate evidence supported continental drift?

Tropical plant fossils in polar regions.

What did sonar reveal about the sea floor?

Mountain chains and deep trenches.

What process creates new sea floor?

Sea floor spreading.

Who developed sea floor spreading?

Harry Hess.

What is the mid‑ocean ridge?

A continuous underwater mountain range.

What destroys ocean floor at trenches?

Subduction.

What did Vine and Matthews explain?

Magnetic stripes from alternating polarity.

What strongly supports sea floor spreading?

Alternating magnetic polarity stripes.

What is the age of the oldest ocean floor?

180 million years.

What are the three types of plate boundaries?

Divergent, Convergent, Transform.

Where are divergent boundaries found?

Along oceanic ridges.

What happens at convergent boundaries?

One plate subducts beneath another.

What is a transform boundary?

Plates grinding past each other.

What causes hotspot volcanism?

Mantle plumes.

What evidence suggests mantle plumes exist?

Slow seismic wave movement through hot rock.

Why are hotspots significant?

They show volcanic activity away from plate boundaries.

What is the Wilson cycle?

The life cycle of ocean basins.

What is the final stage of the Wilson cycle?

The suturing stage.

What does bathymetry measure?

Ocean depth and seafloor topography.

Which satellite mapped the sea floor in the 1980s?

Geosat.

What produces seismic reflection profiles?

Explosions or air guns.

What is the unit of ocean depth?

Fathom.

What does an echo sounder do?

Measures depth using sound travel time.

What was the first multibeam echo sounder?

Seabeam.

What instrument creates strip maps of the sea floor?

Side‑scan sonar.

How do satellites map sea floor features?

By detecting gravitational effects on sea surface height.

What was the first systematic bathymetric survey?

HMS Challenger expedition (1872–1876).

What makes up the continental rise?

Turbidite deposits.

What distinguishes passive vs. active margins?

Proximity to plate boundaries.

Which margin has high tectonic activity?

Active margins.

What is the average continental shelf slope?

About 0.1°.

At what depth is the shelf break?

135 meters.

What characterizes transform active margins?

Offshore faults parallel to the transform boundary.

What are abyssal plains?

Flat deep‑ocean depositional surfaces.

Where are most abyssal plains found?

Atlantic and Indian Oceans.

What are seamounts?

Volcanic peaks rising >1 km above the sea floor.

What is a tablemount (guyot)?

A volcano with a flattened top.

What are abyssal hills?

Volcanic features <1000 m tall.

What is the deepest point on Earth?

Challenger Deep (11,022 m).

What is the mid‑ocean ridge made of?

Basaltic lavas.

What percent of Earth's surface is mid‑ocean ridge?

23%

What volcanic feature is common at mid‑ocean ridges?

Pillow basalts.

What are hydrothermal vents?

Sea floor hot springs formed by seawater interacting with magma.

What ecosystems live at hydrothermal vents?

Tubeworms, clams, and other chemosynthetic communities.