Lesson 17: Marine Systems Flashcards
How does ocean surface salinity and water temperature vary? (Highest vs. lowest)
Salinity varies, especially at the surface:
- higher in mid-latitude oceans and restricted areas of the ocean
- lower near equator and near the mouths of major rivers
Temperature of surface seawater varies with latitude
- near freezing close to the poles
- high near equator and restricted areas
What are the ocean bathymertry features? (4)
- Continental shelf
- Continental Slope
- Continental Rise
- Abyssal plain
Characterize continental shelf. (3)
Edge of a continent that lies under the ocean
- continental crust
Extends from the shoreline of a continent to the shelf break.
Broad gently sloping planes covered by relatively shallow water; allows sunlight to penetrate
Characterize continental slope.
Ocean floor from the shelf break to the continental rise/oceanic trench
Typical depth: 200 meters
Relatively steep grade 3 - 6 degrees
Characterize continental rise.
Underlain by oceanic crust
A wedge of sediments that extends from the lower part of the continental slope to the deep-sea floor.
Slopes between 0.5 and 1 degree
- Slope angle decreases gradually
Characterize abyssal plain.
Deepest, flattest part of the ocean.
- not uniformly flat
Found where continental rise ends
Slope is less than 1:1,000
No sunlight
What are happy coral conditions? (5)
- Sunlight (shallow water)
- Clear water
- Warm water
- Clean water
- Salt water
What is coral bleaching?
When corals are stressed by changes in conditions they expel the symbiotic algae living in their tissues, causing them to turn completely white.
What are the different reef types? (4)
- Fringing Reef
- Barrier Reefs
- Atolls
- Platform/Patch Reefs
Characterize fringing reefs.
Grow seaward directly from the shore
Attached to landmasses
Most common type of reef
What is an example of a fringing reef?
Greater Caribbean region:
- Cuba
- The Bahamas
Characterize barrier reefs.(2)
Linear reefs that are parallel to the shore and separated from the shore by a lagoon
Complex, consisting of many reefs.
What is an example of a barrier reef?
The Great Barrier Reef Queensland Australia
Mesoamerican Reef (MAR)
Characterize atolls. (2)
What occurs when a fringing reef continues to grow upward from a volcanic island that has sunk entirely below sea level.
- no exposed central landmass
Outer margin is the site of the most vigorous coral growth
A lagoon is protected inside the atoll
What is an example of an Atoll?
Ebon Atoll, Marshall Islands
Characterize platform/patch reefs.
Grow in isolated patches in warm, shallow water on the continental shelf.
More abundant during past geologic periods of warmer climates
Seem to be randomly distributed
How are seafloor sediments classified?
by their origin
What are the different sediment classification types? (5)
- Terrigenous - from land
- Volcanogenous - ejected from volcanoes
- Biogenous - from life in oceans
- Hydrogenous - precipitated from water
- Cosmogenous - extraterrestrial
How are Terrigenous Sediments transported? (5)
- Streams
- Wind (Aeolian)
- Glaciers
- Submarine Canyons/Turbidites
- Sea level changes
How are submarine canyons characterized?
Major incisions into continental shelf, continental slope and rise acting as super-highways transporting sediment, organic carbon, and other nutrients from land to the deep ocean floor.
Highly dynamic zones
Usually have v-shaped profiles
How are submarine fans characterized?
Accumulations of sediment deposited at the termini of land-to-deep-sea sediment-routing systems
Are the largest detrital (sediment) accumulations on Earth
Receive sediment through submarine canyon-channel streams
Exhibit radial-/cone-/fan-like morphologies
How are turbidites characterized?
The product of sediment gravity flows (turbidity currents)
- turbulence is the dominant mechanisms for grain support in a sediment gravity flow
High-velocity erosive events
- carve submarine canyons
What is the most-likely source of the red clay in the ocean?
Aeolian dust brought in from the continents by the wind.
The source of IRD is ___.
Glaciers (ice-sheets)