I think it is the wave energy.
Wave energy also known as the ocean energy is the energy harnessed from the ocean or sea waves. It is a source of power that comes from the endless march of the waves as they roll into the shore then back out. Using wave energy is advantageous as they are environmental friendly as there are no harmful byproducts, and also the energy from waves can be taken directly into electricity-producing machinery and used to power generators.
Because the sun evaporates the water out of the clothes
The lower the frequency the lower the pitch sound.
The density of seawater plays a vital role in causing ocean currents and circulating heat because of the fact that dense water sinks below less dense. long story short, seawater is the problem because its denser than pure water.