Which usually had greater salinity deep or surface currents?

Deep ocean currents typically have greater salinity compared to surface currents. This is primarily due to factors such as evaporation in warmer regions and the formation of sea ice, which increases the concentration of salts in the water. Additionally, deep currents are often sourced from colder, saltier water masses that have sunk and are less affected by precipitation and runoff that can dilute surface salinity.