How does the speed of sound change as it moves from the surface of the ocean to 1000 meters below to surface?
a.)the speed increases because the water is less dense at warmer temperatures. b.)the speed decreases because the water is denser at warmer temperatures.
c.)the speed increases because at cooler temperatures the water has more mechanical energy.
d.) the speed decreases because at cooler temperatures the water has less mechanical energy.

Answer;

D.) The speed decreases because at cooler temperatures the water has less mechanical energy.

Explanation; Sound travels about 1500 meters per second in seawater. The speed of sound in sea water varies depending on factors such as water depth, place to place, morning to evening, etc.The change in the speed sound is associated to the variables in the ocean such as temperature, salinity and the pressure. The temperature of ocean water decreases with depth, so as the depth increases the water gets cooler. And since the speed of sound in water increases with increase in water temperature, then an increase in depth would mean a decrease in the speed of the sound.