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GammaFork t1_is4j6lc wrote

Reply to comment by his_rotundity_ in Does the salinity of ocean water increase as depth increases? by rhinotomus

Though oddly the densest, deepest class of global water, Antarctic Bottom Water, is actually fresher than the overlying Circumpolar Deep Water or North Atlantic Deep Water!

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CroStormShadow t1_is76unb wrote

What makes that possible?

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brunswick t1_isaflbs wrote

The density of seawater is affected by both temperature and salinity. The exact relationship is pretty complicated, but fresher water can be denser than more saline water if it's considerably colder. That's why physical oceanography has a concept of spiciness. Warm and salty water is 'spicy' while cold and fresher water is 'minty.' Because density is affected by both salinity and temperature, minty and spicy water can potentially have exactly the same density.

Here are a couple of figures I pulled from Talley's Descriptive Physical Oceanography textbook. Here's a map showing the temperature and the salinity of the circumpolar deep water around Antarctica. If you compare it to the Antarctic bottom water, you can see that the Antarctic bottom water is a little fresher than the CDW, but it's considerably colder.

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