Oceans

What are the four major features of the ocean basins

Abyssal Plains, Abyssal Hills and Seamounts, Oceanic Ridge and Rises, and Oceanic Trenches

What are the four main classifications of marine sediments by origin?

Lithogenous, biogenous, hydrogenous, and cosmogenous

What is the term for the vertical ocean structure characterized by a sharp change in temperature?

Thermocline

Name the five oceans listed in the source material

Pacific, Atlantic, Indian, Southern and Arctic

What is the average depth of the Pacific Ocean?

4282 meters

What is the average depth of the Atlantic Ocean?

3926 meters

What is the average depth of the Indian Ocean?

3963 meters

Which of the five major oceans is the shallowest, with an average depth of 1205 meters?

The Arctic Ocean

According to the hypsographic curve data, what percentage of the Earth’s surface is covered by ocean?

70.8%

What is the mean depth of the world’s oceans?

3,688 meters

What is the mean elevation of land on Earth?

840 meters

What are the four main components of a continental margin, starting from the coast?

Continental shelf, shelf break, continental slope, and continental rise

The shallow, submerged edge of a continent is known as the….

Continetal shelf

What is the approximate average width of the continental shelf?

Around 65 km

What is the typical maximum depth of the continental shelf?

Approximately 130 meters

What geological process strongly influences the features of continental margins?

Plate tectonics, particularly the proximity to divergence or convergence zones

What is the term for the mountainous chain at a spreading centre in the ocean?

Mid-ocean ridge

How long is the global mid-ocean ridge and rise system?

Approximately 65,000 km

The mid-ocean ridge system can be displaced by geological features known as ___?

Transform faults (or fracture zones)

What are Abyssal Plains?

Flat, featureless areas of the deep ocean floor covered in sediment

Abyssal plains cover what percentage of the Earth’s total surface?

Greater than 30%

At what depth range are abyssal plains typically found?

Between 3700 and 5500 meters

Where are abyssal plains generally located within an ocean basin?

Between the continental margin and the mid-ocean ridge system

Sediments derived from pre-existing rock, like those from the Yukon Delta, are classified as what type?

Lithogenous sediments

Sediments derived from the remains of marine organisms, such as diatoms and coccolithophores, are classified as ___.

Biogenous sediments

What are two main chemical compositions of biogenous oozes?

Siliceous (from organisms like diatoms and radiolarians) and calcareous (from organisms like coccolithophores and pteropods).

What is the term for sediments that are precipitated directly from seawater, such as manganese nodules?

Hydrogenous sediments

Sediments derived from extraterrestrial sources, such as tektite-like glass, are known as?

Cosmogenous sediments

What is the Carbonate Compensation Depth (CCD)?

The depth in the ocean below which the rate of dissolution of calcium carbonate is greater than its rate of accumulation

Above the CCD, ___ oozes are more common, while below it, ____ oozes predominate

Calcareous; siliceous

What is the term for sediments deposited on the continental shelf, close to land?

Neritic sediments

What is the term for fine-grained sediments deposited in the deep-ocean basin, far from land?

Pelagic sediments

The ocean can be described as a three-layered structure. What is the uppermost layer called?

The mixed (or Surface) layer

What is the depth range of the mixed (surface) layer in the ocean?

From the surface down to about 200 meters

Which layer of the ocean is characterized as being warm and well-mixed, or isothermal, for most of the year?

The mixed (surface) layer

What is the name of the ocean layer found between approximately 200 and 1000 meters?

The Intermediate layer

The sharp temperature change, or thermocline, is located within which of the three main ocean layers?

The Intermediate layer

What is the deepest of the three ocean layers, found below 1000 meters?

The bottom layer

How is the bottom layer of the ocean generally characterized in terms of temperature and mixing?

It is a uniformly cold layer with lower levels of mixing

What drives surface currents in the ocean?

Winds, cooling, and differences in precipitation versus evaporation

A sharp change in salinity with depth in the ocean is called a ___

Halocine

A sharp change in density with depth in the ocean is called a?

Pycnocline

Within which vertical structure zone do the halocline and pycnocline typically occur?

Within the intermediate layer (and associated intermediate currents).

Deep ocean currents below the pycnocline are also known by what name?

Thermohaline Circulation

What causes the formation of a seasonal thermocline?

Summer heating of the surface waters

How does latitude affect the seasonal thermocline?

The development and intensity of the seasonal thermocline vary with latitude due to differences in solar heating

What are the two primary factors that determine vertical zonation in the ocean?

The depth of the pycnocline and the depth of light penetration

How does the depth of light penetration affect vertical zonation?

It determines the zones where photosynthesis (O₂ production) can occur versus zones dominated by respiration (CO₂ production).

What is the approximate relationship between wind speed and the speed of the surface current it generates?

The current speed (U) is typically less than or equal to 3% of the wind speed (W)

What does the formula U ≤ 3% W describe in oceanography?

It describes the relationship between surface current speed (U) and wind speed (W).

What is the ultimate source of energy driving atmosphere-ocean interactions?

Solar radiation is the ultimate energy source

In which layer of the atmosphere, within 10 km of the surface, does most weather occur?

Most weather occurs in the troposphere

Compared to cold air, warm air is less __ and hold more water

Dense

The Earth maintains an energy balance between incoming short-wave solar radiation and outgoing long-wave ___ radiation

Infrared

What is the primary cause of seasonal differences in solar energy flux on Earth?

The obliquity (axial tilt) of the Earth relative to the sun

Why do equatorial regions receive more concentrated solar energy than polar regions?

Due to latitudinal differences in the sun’s angle, causing the energy to be spread over a smaller area at the equator

What is the term for heat transfer in a fluid where warmer, less dense material rises and cooler, denser material sinks

Convection

What is the angular velocity (Ω) of the Earth’s rotation?

The angular velocity in 360° in 24 hours, or 15° per hour

How does the linear velocity of Earth’s surface change from the equator to the poles?

It is fastest at the equator (approx. 1674 km/hr) and slowest at the poles (approx. 0 km/hr)

What is the name for the apparent force that deflects moving objects on a rotating sphere?

The Coriolis effect

In which direction does the Coriolis effect deflect moving fluids in the Northern Hemisphere?

To the right of their direction of motion

In which direction does the Coriolis effect deflect moving fluids in the Southern Hemisphere

To the left of their direction of motion

The Coriolis effect divides the single large atmospheric convection current in each hemisphere into how many distinct cells?

Three cells in each hemisphere

What are the names of the three atmospheric circulation cells in each hemisphere, starting from the equator?

Hadley Cell, Ferrel Cell, and Polar Cell

The calm, low-pressure area near the equator where the Hadley cells converge and air rises is known as the ____.

Doldrums

The calm, high-pressure areas at approximately 30°S latitude, where air sinks, are called the ___.

Horse Latitudes

The zone where trade winds from the Northern and Southern Hemispheres converge is known as the ____?

Intertropical Convergence Zone (ITCZ)

How are winds and ocean currents conventionally named?

Winds are named for the direction they come FROM, while currents are named for the direction they flow TO.

The theoretical model of wind-driven water movement where each successive layer of water moves at an angle to the one above it is known as the ___.

Ekman Spiral

What is Ekman Transport?

It is the net motion of the upper water column, which is theoretically 90° to the right of the wind direction in the Northern Hemisphere (and 90° left to the SH).

Large, circular surface current systems that distribute heat from the equator to the poles are known as oceanic ____.

Gyres

List the four primary currents that constitute the North Atlantic Gyre

The Gulf Stream, North Atlantic Current, Canary Current, and North Equatorial Current

In a geostrophic gyre, what two opposing forces create a dynamic balance, resulting in a ‘hill’ of water in the gyre’s centre?

The Coriolis effect (pushing water inward) and the pressure gradient force from gravity (pushing water outward and down)

The downward water movement under the central '“hill” of a geostrophic gyre is an example of what process?

Downwelling

How many major geostrophic gyres are there in the world’s oceans?

There are 5 major geostrophic gyres

Is the Antarctic Circumpolar Current (West Wind Drift) considered a geostrophic gyre?

No, it is not

Western Boundary Current

A fast, narrow, and deep ocean current flowing along the western side of an ocean basin, like the Gulf Stream

Eastern Boundary Current

A slow, broad, and shallow ocean current flowing along the eastern side of an ocean basin like the Canary Current

Compare the flow volume (in Sverdrups) of the Gulf Stream to the Canary Current

Gulf Stream has a much larger flow (approx. 55 Sv) compared to the Canary Current (approx. 16 Sv)

Currents that flow predominantly east or west, connecting the boundary currents of a gyre, are called ___ currents.

Transverse

The West Wind Drift, or Antarctic Circumpolar Current, is classified as what specific type of current?

An east transverse current

In the open ocean, wind patterns that cause surface water to diverge, such as under cyclonic winds, result in what process?

Upwelling

In the open ocean, wind patterns that cause surface water to converge, such as at the ITCZ, result in what process?

Downwelling

In the Northern Hemisphere, winds blowing parallel to a coastline that induce offshore Ekman transport cause what phenomenon?

Coastal upwelling

In the Northern Hemisphere, winds blowing parallel to a coastline that induce onshore Ekman transport cause what phenomenon?

Coastal downwelling

What is the name for the large-scale ocean circulation driven by density differences from temperature and salinity?

Thermohaline circulation

Thermohaline circulation below the pycnocline accounts for approximately what percentage of all water movement in the ocean?

Approximately 90%

The global system of deep-ocean circulation, where dense water sinks at the poles and slowly upwells elsewhere, is often called the ____.

Ocean Conveyor Belt

What is the approximate timescale for a parcel of water to complete a full cycle of the global thermohaline circulation?

Approximately 1000 years

The water mass found in contact with the seafloor is classified as ___ waters.

Bottom waters

The water mass found between approximately 200 m and the main thermocline is classified as ____ waters.

Central waters

The water mass found below central waters but generally above 1500 m is classified as ____ waters.

Intermediate waters

What is the Atlantic Meridional Overturning Circulation (AMOC)?

It is a major component of the thermohaline circulation in the Atlantic Ocean, characterized by the northward flow of warm water and southward flow of cold, deep water.

A Sverdrup (sv) is a unit of volume transport equivalent to ____ cubic meters per second

10^6

In the context of atmospheric science, why is humid air less dense than dry air at the same temperature and pressure?

Because the molecular weight of water (H₂O) is less than the average molecular weight of nitrogen (N₂) and oxygen (O₂).

What are the two primary sources of the ions that make up the ocean’s salt content?

The Earth’s crust and mantle are the two primary sources

The ocean is composed of approximately 96% ____ and 4% ____.

water; salt

Historically, how was ocean salinity determined?

It was originally based on a titration of chloride in solution, which is easy to measure.

How is a typical ocean salinity of 35 parts per thousand expressed in grams per litre (g/L) and practical salinity units (psu)?

It is expressed as 35 g/L or 35.00 psu

What is the ‘Principle of Constant Properties’ in oceanography?

It states that although the total salinity may vary, the relative proportions of the major dissolved ions in seawater remain constant.