ABSTRACT
If the thermohaline slows, it will reduce the rate of mixing of the ocean waters. This will tend to isolate the surface ocean (where the phytoplankton resides) from the deep ocean (where most of the nutrients are found). It will mean a reduction in oxygen supply to the deep oceans, which would eventually become anoxic (depleted of oxygen). The result of this stratification process would not only be to kill off many deep ocean aerobic marine species but also to promote anaerobic organisms, such as sulphate reducers, that produce hydrogen sulfide as a waste product. This, in turn, would deplete soluble iron, which is an important nutrient source for phytoplankton and could serve to reduce biological activity and primary production.
