Garvity forces salt and wind
During certain seasons gravity forces frome the moon and earth's rotation create strong currents. the moon pushes water away from the surface. this surface water is replaced with water that rises from deep down in the ocean. Waterat the bottom of the ocean has a lot of nutrients. When these currents rise from the ocean bottom to the surface the process is called upwelling. The main benefit of upwelling is that fish and other marine life can easily be found on the surface.