What effect does water temperature have on thermohaline circulation?

Question

Specifically, the Atlantic side of the global THC.

Answer 1

As Cap 10 has mentioned, density is the driving factor but density is controlled by temperature and salinity - hence the name thermo (temperature) haline (salt). Salt water is at it's densest at it's freezing point (approx -2°C depending on salinity), freshwater is at it's densest at 4°C.

Not knowing how much you already know about THC (or MOC) it's probably better to give you a couple of links. I don't want to teach you to suck eggs but at the same time don't want to waffle on about things that are meaningless.

http://en.wikipedia.org/wiki/Thermohaline_circulation
http://www.sciencemag.org/cgi/reprint/298/5596/1179.pdf
http://www.agu.org/revgeophys/fine00/fine00.html

Answer 2

The thermochaline circulation is not really run by water temperature, it is driven by density. Water temperature does play a role in the fact water is densest at 4 degrees C.