Currents and Marine Life. Currents are powerful physical forces in the seas. They move water and heat around the globe, and help determine the chemical make-up of the water column. Currents also are a major factor in ocean ecosystems. Two types of current motion, upwelling and downwelling, strongly influence the distribution and abundance of marine life. Upwelling Currents play a huge role in marine productivity, through a process called upwelling. Sea life is concentrated in the sunlit waters near the surface, but most organic matter is far below, in deep waters and on the sea floor. When currents upwell, or flow up to the surface from beneath, they sweep vital nutrients back to where they're needed most.