GED Science TestEarth and Space ScienceMedium
A research vessel is collecting data on ocean currents in the North Atlantic. They observe a deep, cold current flowing southward from the Arctic region, carrying high salinity water. This current eventually sinks and travels along the ocean floor. What is the primary driving force behind this specific type of ocean circulation?
- ACoriolis effect
- BDensity differences
- CTidal forces
- DPrevailing winds
Show answer & explanationAnswer & explanation
Correct answer: B. Density differences
The described current is part of the thermohaline circulation, which is driven by differences in water density caused by variations in temperature (thermo) and salinity (haline). Cold, salty water is denser and sinks.
Why the other options are wrong
- A. The Coriolis effect deflects currents but is not the primary driving force for deep, density-driven circulation.
- C. Tidal forces cause short-period changes in sea level but do not drive large-scale, long-term deep ocean currents.
- D. Prevailing winds primarily drive surface currents, not deep ocean circulation.
Thermohaline Circulation
A global-scale system of ocean currents driven by differences in water density, which are controlled by temperature (thermo) and salinity (haline). It plays a crucial role in redistributing heat around the Earth.
- Driven by temperature and salinity differences.
- Cold, salty water is denser and sinks.
- Acts like a global conveyor belt for heat and nutrients.
Memory trick: Ocean's 'Density Dance' Drives Deep Currents