Ocean Characteristics Flashcards
What are the five oceans in order of size?
Pacific Ocean, Atlantic Ocean, Indian Ocean, Southern Ocean, Arctic Ocean
What is the Tethys and its significance for the present distribution of the oceans?
The Tethys was an equatorial east-west ocean between the northern and southern continents that gradually closed, leaving only the Mediterranean Sea today.
How is the Southern Ocean geographically demarcated?
The Southern Ocean is defined as the waters between the polar front and Antarctica, with a geographic boundary given by the 10 °C July surface temperature isotherm.
What is the difference between pelagic and benthic zones?
Pelagic zones refer to the water column, while benthic zones include the seafloor.
What is a continental shelf and where are the largest shelves typically found?
A continental shelf is a submerged continental landmass that extends from the mainland. The largest continental shelves are typically found off the coast of Siberia, in South Asia/North Australia, and off the Atlantic coast of Argentina.
How does the Coriolis effect influence ocean currents?
The Coriolis effect deflects ocean currents to the right (clockwise) in the Northern Hemisphere and to the left (counterclockwise) in the Southern Hemisphere.
Explain the concept of the Ekman spiral.
The Ekman spiral describes the deflection of water layers by the wind, with the uppermost layer deflected 45 degrees from the wind direction and deeper layers deflected even further, resulting in a net displacement of 90 degrees from the wind direction.
What is thermohaline circulation (THC)?
THC is a global system of vertical and horizontal ocean currents driven by temperature and salinity differences, playing an important role in global heat and salt transport.
Name two regions with significant upwelling.
Coasts of West Africa and South America
What is the importance of upwelling?
Upwelling brings nutrient-rich deep water to the surface, leading to increased primary production.
How do temperature and salinity affect the density of seawater?
An increase in temperature leads to lower density, while an increase in salinity leads to higher density.
Fill in the blank: An _______ is a deep, flat region of the seafloor.
abyssal plain
What does advection refer to?
The transport of material or properties by the movement of a fluid or gas.
What is equatorial upwelling?
Upwelling caused by divergence in surface currents in equatorial regions.
Define brackish water.
Water with a salinity between that of seawater and freshwater (typically between 0.5 and 30 PSU).
What is the Coriolis effect?
The deflection of objects (such as ocean currents) due to the Earth’s rotation.
What is the diffusive boundary layer (DBL)?
A thin layer of water around a cell or surface that restricts the diffusion of substances.
Describe the Ekman spiral.
A spiral change in the direction of ocean currents with increasing depth, caused by the wind and the Coriolis effect.
What does eurytherm mean?
Organisms that can survive in a wide temperature range.
What is a halocline?
A layer of water in which the salt content changes significantly with depth.
What does HNLC stand for?
High Nutrient Low Chlorophyll
What are homeothermic organisms?
Organisms that can maintain a constant body temperature (e.g., mammals).
What is convergence in oceanography?
The meeting of water masses that causes water to sink.
What is a continental slope?
The steep transition between the continental shelf and the deep sea.
Define marginal sea.
A body of water that is more or less enclosed by land masses and is connected to the oceans.
What is an ocean front?
A boundary between two different water masses, characterized by temperature, salinity or density differences.
Fill in the blank: The _______ zone refers to the water column.
pelagic
What does poikilotherm mean?
Organisms whose body temperature adapts to the ambient temperature (e.g., fish).
What is the polar front?
The zone around the 60th parallel where two air masses meet and form a strong temperature gradient.
What is a pycnocline?
A layer of water in which the density changes greatly with depth.
What does SST stand for?
Sea Surface Temperature
Define stenothermal organisms.
Organisms that can only survive in a very narrow temperature range.
What is a subduction zone?
A region where one tectonic plate subducts beneath another, often forming deep-sea trenches.
What is a Sverdrup?
A unit for the volume transport of water, corresponding to 10^6 cubic meters per second.
What is thermal stratification?
Stratification of water layers due to temperature differences.
What is a thermocline?
A layer of water in which the temperature varies considerably with depth.
What does thermohaline circulation (THC) refer to?
A global system of ocean currents driven by differences in temperature and salinity.
What is upwelling?
Rising of deeper, usually nutrient-rich water to the surface.
