Convection is one of the major processes that cause ocean currents. The water warmed at the Equator flows north (or south in the southern hemisphere) as a warm western boundary current. In the North Atlantic, this is the Gulf Stream. All these currents bring a warm climate to their surroundings. In fact, the British Isles are a lot warmer than would be expected from their latitude because of the Gulf Stream. On the other hand, the east coast of Canada, at the same latitude, has a much colder climate due to the cold Labrador Current coming from the Pole. The eastern boundary currents of the great ocean gyres bring cold water from the Poles back to the Equator. They give their surroundings a cooler climate. For example, the California current makess most of the US west coast pretty cool and foggy. You can't even get into the water without a wetsuit! Upwellings are usually found along these eastern boundary currents: the Peru, California, Canary, and Benguela currents all have them.