NaimExplain

How does sediment accumulation affect the bathymetry of a spreading center? Where are the affects more pronounced? Answer: Sediment accumulation will smooth out the bathymetric features and it is more pronounced with greater distance from the spreading center because there has been a longer amount of time for sediments to accumulate.

What is occurring at hydrothermal events in terms of water exchange? Answer: Cold ocean water is seeping through fissures in the crust. When the water comes close to the magma chamber, it is warmed, then rises and boils out of the fissures near the center of the rift zone

What is the continental rise? Where is it found? Answer: It is formed by the accumulation of sediments at the base of the continental slope and only occurs as passive margins

What are the characteristics of a passive margin? Give an example. Answer: There is little earthquake activity. Faces a divergent plate boundary. Has a broad continental shelf. The Atlantic Ocean

What are the characteristics of an active Margin? Give an example Answer: There is earthquake and volcanic activity. Faces a convergent boundary. Narrow continental shelf. Pacific

Why does the continental shelf in the Gulf of Mexico have numerous pits or pockmarks? Answer: The Mississippi river and other rivers have deposited large amounts of sediment on the shelf. The weight of the sediments causes salt domes to rise and spread out, the dissolve and collapse. causing the pits

What is important about the pockmarks and pits of the Gulf of Mexicos continental shelf? Answer: They cause oil and gas deposits to rise towards the surface and be more accessible.

How are submarine canyons aligned with the continental shelf and how are they formed Answer: They are aligned at right angles with the shelf and they are formed by turbidity currents

What physical property of water can sound be used to measure? Answer: Temperature

What is the photic zone? How deep is it in coastal waters versus the open ocean? Answer: The photic zone is the upper layer of the ocean that is well-lit and where most primary production occurs. It is approximately 40 m deep in coastal waters and 100m deep in the open ocean

What wavelength (color) of light penetrates deepest in the ocean? Which is attenuated most rapidly in the surface? Answer: Blue light penetrates deepest, red light is absorbed at the shallowest depths

What is the speed of sound in the surface ocean? Why does the speed decrease with increasing depth to a certain point? Answer: 1500 meters per second. The speed decreases with depth as the temperature of the water decreases. (NOTE: at a certain point, increasing pressure causes the sound speed to increase again)

What are three things that can happen to light as it enters water? Answer: It can be refracted, absorbed, or scattered

Compare the speed and distance that sound travels in the ocean versus air Answer: Sound travels faster and farther in the ocean than in air

Why is light refracted when it enters water from air? Answer: There is a change in density, the water is more dense than the air and the light travels more slowly and is refracted

San Franciso and Norfolk are both cities on the coast. Why does Norfolk have much greater temperature fluctuations through the seasons? Answer: The prevailing winds are to the East and so the air the flows over Norfolk is influenced by land temperatures while the air the flows over San Francisco is moderated in temperature by flowing over the ocean which experiences fewer temperature fluctuations over the seasons in comparison to land

In what regions of the Earth do SURFACE ocean temperatures fluctuate the most over the year? Answer: temperate regions

Why are the SURFACE ocean waters in the tropics less salty than in temperate regions? Answer: Precipitation greatly exceed evaporation and this leads to fresher surface waters

What is the pycnocline? The thermocline? The halocline? Answer: Pycnocline-the zone where density increases rapidly with depth. Thermocline--zone where temperature changes (usually decreases) rapidly with depth. Halocline--zone where salinity changes (usually increases) rapidly with depth

How do seasonal changes in sea ice cover provide a global thermal buffer? Answer: As ice changes state from solid to liquid, large amounts of heat are required to undergo the latent heat of fusion during which there is no temperature change. The Earth can absorb large amounts of heat and experience no change in temperature because the heat is 'used' to convert ice to liquid water (the reverse process buffers against large drops in temperature as the Earth loses heat)