Global Conveyor Belt 2007: Hamster Wheel Or Hemicuda?

Some new waves, pun intended, are being generated this week concerning the meridional overturning circulation (MOC). You are already familiar with the MOC as the ocean conveyor belt. To refresh your memory, the MOC is a thermohaline current, so named because currents are forced by differences in temperature and salinity both influencing the density of water, i.e. a density-driven current. So to explain the MOC, we will follow a single water mass and we'll call him Timmy. We'll start with Timmy in the equatorial Atlantic. Here, Timmy is warm and salty, like a pirate. The Gulf Stream is a big bully and forces Timmy away from his pleasant tropical vacation towards the Arctic. Here, Timmy obviously becomes colder which also makes him dense and not just in the head. Timmy's new found weight issues cause him to sink to the dark, deep seafloor. Just as Timmy gets comfortable the next water mass behind Timmy, Bobby, pushes Timmy out of the way...