Which way will the supply curve shift if there is a decrease in supply?

What is the general rule about surface currents? cold water flows along the ocean floor towards the equator. the east coasts of continents have cold surface currents, and the west coasts of continents have warm surface currents. seasonal and constant offshore winds create significant upwelling along the west coasts of south and north america and africa. the west coasts of continents have cold surface currents, and the east coasts of continents have warm surface currents.