Circulation, oceanic abyssal

The cadmium/calcium ratio is a proxy for the nutrient (phosphate) content of sea water that reflects abyssal circulation patterns. Carbon isotope ratios also reflect deep-ocean circulation and the strength of organic matter fluxes to the seafloor. 

In this section we briefly review what controls the density of seawater and the vertical density stratification of the ocean. Surface currents, abyssal circulation, and thermocline circulation are considered individually. 

Although the general circulation patterns are fairly well known, it is difficult to quantify the rates of the various flows. Abyssal circulation is generally quite slow and variable on short time scales. The calculation of the rate of formation of abyssal water is also fraught with uncertainty. Probably the most promising means of assigning the time dimension to oceanic processes is through the study of the distribution of radioactive chemical tracers. Difficulties associated with the interpretation of radioactive tracer distributions lie both in the models used, nonconservative interactions, and the difference between the time scale of the physical transport phenomenon and the mean life of the tracer. 

Arons A. B. and. Stommel H. (1967) On the abyssal circulation of the world ocean 111. An advection-lateral mixing model of the distribution of a tracer property in an ocean basin. Deep-Sea Res. 14, 441-457. 

The abyssal circulation model of Stommel (1958) (Fig. 9-11) predicted that the deep waters flow most intensely along the western boundaries in all oceans and gradually mix into the interior during this flow. 

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