Objective: Learn about the connection between deep circulation in the ocean and the surface circulation and how both influence long-term climate change
Climate change over the course of millennia,
centuries, even decades, is influenced the flow of deep water in the ocean.
Remember during a previous expedition we
called the flow of deep water, thermohaline circulation.
The name itself, provides a clue to the
driving force behind this circulation,
thermo => temperature
haline => salinity
temperature + salinity = density
So thermohaline circulation is driven by the
density of the water, or better said, the Earth's gravitational field. In other words, either cold or salty water has
a high density and therefore sinks to the bottom of the sea. So thermohaline circulation is largely driven by the
sinking of water, especially very cold water from the polar regions, but as we will see,
sometimes this water rises, such as in the Pacific, thereby creating an endless cycle or
conveyor belt of circulation.