Essentials of Oceanography 13th Edition
Practice Test with Explanations
2026/2027Complete Exam-Style Questions
with Correct Answers & Detailed Rationales
1.
Which statement best explains why ocean water has a higher
density than freshwater under comparable temperature and
pressure conditions?
A. Ocean water contains dissolved salts that increase its mass
per unit volume
B. Ocean water contains less dissolved oxygen than freshwater
C. Ocean water has a greater proportion of hydrogen atoms
D. Ocean water absorbs more solar radiation than freshwater
Answer: A. Ocean water contains dissolved salts that increase
its mass per unit volume
Dissolved salts add mass to seawater without increasing its
volume proportionally, thereby increasing its density.
Temperature and pressure also affect seawater density, but
salinity is a major distinguishing factor between seawater and
freshwater.
,2.
What primarily drives the formation of surface ocean currents?
A. Earthquakes along mid-ocean ridges
B. Wind stress acting on the ocean surface
C. Tidal forces acting independently of the atmosphere
D. Heat released by hydrothermal vents
Answer: B. Wind stress acting on the ocean surface
Surface currents are driven primarily by persistent winds
transferring momentum to the ocean. The resulting circulation
is modified by the Coriolis effect, continental boundaries, and
differences in water density.
3.
Why does the Coriolis effect cause moving water to be
deflected to the right in the Northern Hemisphere?
A. Earth rotates from east to west
B. Gravity is weaker near the equator
C. Earth's rotation causes different latitudes to have different
eastward velocities
D. Ocean water moves toward regions of lower atmospheric
pressure
Answer: C. Earth's rotation causes different latitudes to have
different eastward velocities
,Because Earth rotates, objects moving across its surface retain
momentum associated with their original latitude. This
produces an apparent deflection to the right of motion in the
Northern Hemisphere and to the left in the Southern
Hemisphere.
4.
Which oceanographic process most directly produces
thermohaline circulation?
A. Variations in water density caused primarily by temperature
and salinity differences
B. Daily changes in wind direction over coastal regions
C. Gravitational attraction between the Moon and Earth's crust
D. Wave refraction around headlands
Answer: A. Variations in water density caused primarily by
temperature and salinity differences
Thermohaline circulation is associated with density differences
controlled mainly by temperature and salinity. Cold, salty water
can become sufficiently dense to sink, contributing to deep-
ocean circulation.
5.
Which property of seawater generally decreases as
temperature increases, assuming salinity and pressure remain
constant?
, A. Volume
B. Density
C. Thermal energy
D. Molecular motion
Answer: B. Density
Seawater generally becomes less dense as it warms because
thermal expansion increases its volume. The relationship is
fundamental to ocean stratification and circulation.
6.
Which feature is characteristic of a passive continental margin?
A. A deep-ocean trench immediately adjacent to the coastline
B. Frequent large earthquakes along the continental edge
C. A broad continental shelf and relatively low tectonic activity
D. A volcanic island arc parallel to the coast
Answer: C. A broad continental shelf and relatively low
tectonic activity
Passive margins generally occur where continental crust
transitions into oceanic crust without an active plate boundary.
They commonly have broad continental shelves, gentle slopes,
and relatively limited tectonic activity.
7.
Practice Test with Explanations
2026/2027Complete Exam-Style Questions
with Correct Answers & Detailed Rationales
1.
Which statement best explains why ocean water has a higher
density than freshwater under comparable temperature and
pressure conditions?
A. Ocean water contains dissolved salts that increase its mass
per unit volume
B. Ocean water contains less dissolved oxygen than freshwater
C. Ocean water has a greater proportion of hydrogen atoms
D. Ocean water absorbs more solar radiation than freshwater
Answer: A. Ocean water contains dissolved salts that increase
its mass per unit volume
Dissolved salts add mass to seawater without increasing its
volume proportionally, thereby increasing its density.
Temperature and pressure also affect seawater density, but
salinity is a major distinguishing factor between seawater and
freshwater.
,2.
What primarily drives the formation of surface ocean currents?
A. Earthquakes along mid-ocean ridges
B. Wind stress acting on the ocean surface
C. Tidal forces acting independently of the atmosphere
D. Heat released by hydrothermal vents
Answer: B. Wind stress acting on the ocean surface
Surface currents are driven primarily by persistent winds
transferring momentum to the ocean. The resulting circulation
is modified by the Coriolis effect, continental boundaries, and
differences in water density.
3.
Why does the Coriolis effect cause moving water to be
deflected to the right in the Northern Hemisphere?
A. Earth rotates from east to west
B. Gravity is weaker near the equator
C. Earth's rotation causes different latitudes to have different
eastward velocities
D. Ocean water moves toward regions of lower atmospheric
pressure
Answer: C. Earth's rotation causes different latitudes to have
different eastward velocities
,Because Earth rotates, objects moving across its surface retain
momentum associated with their original latitude. This
produces an apparent deflection to the right of motion in the
Northern Hemisphere and to the left in the Southern
Hemisphere.
4.
Which oceanographic process most directly produces
thermohaline circulation?
A. Variations in water density caused primarily by temperature
and salinity differences
B. Daily changes in wind direction over coastal regions
C. Gravitational attraction between the Moon and Earth's crust
D. Wave refraction around headlands
Answer: A. Variations in water density caused primarily by
temperature and salinity differences
Thermohaline circulation is associated with density differences
controlled mainly by temperature and salinity. Cold, salty water
can become sufficiently dense to sink, contributing to deep-
ocean circulation.
5.
Which property of seawater generally decreases as
temperature increases, assuming salinity and pressure remain
constant?
, A. Volume
B. Density
C. Thermal energy
D. Molecular motion
Answer: B. Density
Seawater generally becomes less dense as it warms because
thermal expansion increases its volume. The relationship is
fundamental to ocean stratification and circulation.
6.
Which feature is characteristic of a passive continental margin?
A. A deep-ocean trench immediately adjacent to the coastline
B. Frequent large earthquakes along the continental edge
C. A broad continental shelf and relatively low tectonic activity
D. A volcanic island arc parallel to the coast
Answer: C. A broad continental shelf and relatively low
tectonic activity
Passive margins generally occur where continental crust
transitions into oceanic crust without an active plate boundary.
They commonly have broad continental shelves, gentle slopes,
and relatively limited tectonic activity.
7.
