Question

How do salinity and temperature differences influence the movement of seawater?

These differences increase the clarity of seawater.

These differences initiate the downward and upward movement of water masses.

These differences cause significant evaporation rates across the ocean.

These differences lead to the homogenization of oceanic water layers.

Answer 1

These differences initiate the downward and upward movement of water masses.

Explanation: Temperature and salinity determine seawater density (cold and/or salty water is denser and tends to sink; warm and/or fresh water is less dense and tends to rise). Those density-driven vertical movements are the basis of thermohaline circulation (deep-water formation, sinking, and compensating upwelling). The other options are incorrect: clarity is controlled by suspended particles and light, not directly by T/S differences; evaporation is driven mainly by temperature, humidity and wind (not by T/S gradients); and T/S differences produce stratification, not homogenization, of ocean layers.