Oceanography Flashcards
What ocean is on the west side of the US
The pacific
What ocean is on the east side of the US
The Atlantic
What ocean is on the east side of Africa
The Indian
What ocean is on the northern tip?
The arctic
What ocean is from the coast of Antarctica south?
The southern ocean
What is the largest ocean by surface area and depth?
The pacific
Rank the oceans from largest to smallest
Pacific, Atlantic, Indian, southern, arctic
What is a continental margin?
The transition from land to deep sea floor. Basically from crust to crust.
What is an active continental margin? Give an example in the US
A margin where a tectonic plate boundary also lies. Has more geographical activity.
Ex: the west coast is also the plate boundary between the pacific and North America.
What are the characteristics of an active continental margin?
More narrow shelves, steeper slopes, and little to no rise.
What is a passive continental margin? Give an example in the US.
A margin where no tectonic plate boundary occurs, has less geographical activity.
Ex: the East coast of the US
What are the characteristics of a passive continental margin?
Wider shelves, gentle slopes, and a developed rise from long periods of stability.
What is a continental shelf? Is it considered continental or oceanic crust? What is the average extension of a shelf from the coast?
The top part of the continental margin that is shallow and flooded. It is continental crust. Average extension is 80 km.
What part of the continental margin is the most biologically rich?
The continental shelf.
Is the continental shelf smooth or rough? Why?
Smooth, from repeated wave action, being submerged and then I submerged, and other erosion.
What is the shelf break?
The part of the continental margin where the shelf ends and the slope begins and the angle of the sea floor gets steeper.
What is the continental slope? What is it’s average depth?
Area of advance steepness of the continental margin. Usually 3000-5000m deep.
What part of the continental margin do sub marine canyons form? Why?
The continental slope, they form from sediments from land and shelf falling.
Name the parts of the continental margin starting with the most shallow.
Continental shelf, shelf break, continently slope, continental rise, abyssal plain.
What is the continental rise?
The part at the bottom of the slope where continental crust meets oceanic crust.
Why is it difficult to tell where the slope ends and the rise begins?
Because the rise can be covered by layers of accumulated sediment.
What is the abyssal plain?
The deep ocean floor.
What is the flattest region on earth?
The abyssal ocean plains.
What is the benthic zone? What are the organisms called that live there?
The bottom of the ocean and all organisms that live there called benthos.
What is the pelagic zone?
The water column where all swimming and floating organisms live.
What are the two provinces of the pelagic zone? What are they?
The neitic and the oceanic. Neritic is all water from low tide to the shelf break, oceanic is all other open ocean regions.
How many depth zones is the oceanic province are there? List them by name and depth.
Five
1: epipelagic: 0-200
2: mesopelagic 200-1000m
3: bathypelagic 1000-4000m
4: abyssopelagic 4000-6000m
5: hadopelagic 6000 plus
What depth zone of the oceanic province can light reach?
The epipelagic zone receives full sunlight, mesopelagic gets some light but not enough for photosynthesis.
What depth zone is 75% of the ocean at?
The bathypelagic
What depth zone is the water in the deep trenches?
The hadopelagic/hadalpelagic
How many zones is the benthic zone split into? Name them.
1: littoral
2: sublittoral
3: bathyal
4: abyssal
5: hadal
What zone of the benthic zone is only sometimes submerged?
The littoral zone. Also called the spray zone.
What is bathymetry?
The process of measuring the oceans depth.
What is sounding? What are its drawbacks?
A process of measuring used early on that consisted of letting out a lead line until it touched the bottom. It’s only limited to one point at a single moment and it is only useful in shallow waters, very time consuming.
What is a unit of depth called? What is it in feet?
Fathom. 6 feet.
what is sonar?
Sound navigation and ranging.
What is an echo sounder?
The device used in sonar that sends out a pulse then listens for the returning echo. The timing of the returned echo is used to measure depth.
What is the equation for an echo sounder?
D=1/2 VT (depth=1/2 (x) pulse velocity in water (x) time