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What property of water increases when salinity increases?
A Temperature
B Density
C Oxygen
D Pressure
B Density
Cold ocean water is usually ______.
A. Less dense than warm water
B. More dense than warm water
C. Always freshwater
B. More dense than warm water
What causes most surface ocean currents?
A. Wind
B. Earthquakes
C. Tides only
A. Wind
What is salinity?
A. The movement of ocean water
B. The temperature of water
C. The amount of salt in water
D. The depth of the ocean
C. The amount of salt in water
What happens to dense ocean water?
A. It rises
B. It evaporates
C. It sinks
C. It sinks
Upwelling brings what to the ocean surface?
A. Deep, nutrient-rich water
B. Warm water with little oxygen
C. Freshwater from rivers
D. Oil and pollution
A. Deep, nutrient-rich water
Which combination creates the MOST dense seawater?
A. Warm and less salty
B. Warm and salty
C. Cold and salty
C. Cold and salty
How does temperature affect ocean water density?
A. Warmer water becomes more dense
B. Colder water becomes more dense
C. Temperature does not affect density
B. Colder water becomes more dense
Why do deep ocean currents form?
A. Due to differences in density
B. Only because of wind
C. Due to moon phases only
A. Due to differences in density
Which situation would MOST likely cause upwelling?
A. Warm water staying at the surface
B. Wind pushing surface water away
C. Freshwater entering the ocean
D. Ice melting into the ocean
B. Wind pushing surface water away
Which statement best explains thermohaline circulation?
A. Wind controls all ocean movement
B. Ocean currents are caused only by tides
C. Density differences caused by temperature and salinity move water globally
C. Density differences caused by temperature and salinity move water globally
Why are areas with upwelling often rich in sea life?
A. Nutrients rise to the surface
B. There is less oxygen
C. Fish prefer salty water only
A. Nutrients rise to the surface
Which change would MOST likely increase water density?
A.Increasing temperature
B. Decreasing salinity
C. Cooling the water and adding salt
D. Heating the water and adding freshwater
C. Cooling the water and adding salt
A scientist measures two water samples:
Sample A is warm and salty.
Sample B is cold and less salty.
Which sample is MOST likely denser?
Sample A is warm and salty.
If upwelling stopped occurring near a coastline, what would MOST likely happen?
A. Fish populations would increase
B. Nutrient levels near the surface would decrease
C. Salinity would completely disappear
B. Nutrient levels near the surface would decrease
A region of the ocean becomes warmer due to climate change. How would this MOST likely affect density and sinking currents?
A. Density decreases and less sinking occurs
B. Density increases and more sinking occurs
C. Salinity automatically increases
A. Density decreases and less sinking occurs
Why do cold, salty waters near the poles help drive global ocean circulation?
A. Polar water does not move
B. They are pushed by hurricanes
C. They are less dense and rise
D. They become dense enough to sink and move deep currents
D. They become dense enough to sink and move deep currents
Which scenario BEST explains how density differences create ocean currents?
A. Warm water sinks while cold water rises
B. Dense water sinks and less dense water rises
C. Salty water always stays on the surface
D. Surface currents never interact with deep currents
B. Dense water sinks and less dense water rises
A coastal area experiences strong winds that move warm surface water away from shore. What is MOST likely to happen next?
A. Deep, cold, nutrient-rich water rises
B. The ocean becomes less salty immediately
C. Warm water sinks deeper into the ocean
A. Deep, cold, nutrient-rich water rises
Scientists discover that melting glaciers are adding large amounts of freshwater into the North Atlantic Ocean. How could this MOST affect global ocean currents?
A. The freshwater would increase salinity and speed up deep currents
B. The freshwater would decrease density, slowing the sinking of cold water and affecting global circulation
B. The freshwater would decrease density, slowing the sinking of cold water and affecting global circulation
Explain how temperature and salinity work together to affect ocean water density.
Cold water is denser than warm water, and salty water is denser than less salty water. When water is both cold and salty, it becomes very dense and sinks, helping drive deep ocean currents.
Describe how upwelling helps ocean ecosystems.
Upwelling brings cold, nutrient-rich water from deep in the ocean to the surface. These nutrients support plankton growth, which provides food for fish and many other marine organisms.
Why is thermohaline circulation important to Earth’s climate?
Thermohaline circulation moves heat around the planet through deep ocean currents. This helps regulate global temperatures and climate patterns in different regions.
Predict what might happen if ocean salinity decreased in a major area of deep water formation.
Lower salinity would make the water less dense, so less water would sink. This could slow down deep ocean currents and disrupt global ocean circulation patterns.
A scientist notices that surface waters near a coastline are unusually cold and full of fish. What ocean process is MOST likely happening, and why?
Upwelling is likely occurring because cold, nutrient-rich deep water is rising to the surface. The nutrients support plankton growth, attracting many fish to the area.