1) They are caused by low salinity in the water.
2) Deep water currents are caused when nutrient rich water goes away from the water surface. The deep current water currents are important because they return the nutrient rich water back to the surface.
3) Waters that sink to the bottom of the ocean are cold, salty, and dense. Warm water on the other hand is not dense, so it floats to the surface.
4) Water that rises to the surface is warm and has a low level of salinity. It is also less dense than cold water.
5) They are caused by low salinity in the water.
Hope this helps :)
