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16. An Ocean of Layers




The Briny Deep

1. Introduction
2.  Salt in Seawater?
3. Ions of Salt
4. Source of the Salt?
5. Salinity Variability
6.Salinity & Precipitation
7. Salinity Summary
8. Calculating Salinity
9. Ocean Temperature
10. Solar Radiation
11. Properties
12. Light Penetration
13. Temperature
14. Thermocline
15. Density
16. Layering

The result of influence of temperature and salinity on sea water density is that the ocean is layered with warm, low density water at the surface (often called the mixed layer) and cold, high density water at depth (deep water). 

Waters of intermediate temperature and salinity are found in the region of the thermocline and halocline.

Below you can see the distribution of water temperature through the top 1500 meters of the ocean, which shows the great variation in temperature in the thermocline (notice how tightly compressed the lines of equal temperature are between 200 and 800 meters).

Used with Permission of Matthias Tomczak ©Copyright 1997


Think of this layering as that observed in oil and vinegar salad dressing when the two liquids separate into a layer of low density oil at the top and higher density vinegar below, only that the ocean has many layers each with a slightly different density.

The ocean contains many layers composed of different water masses, each formed by a slightly different mechanism.  In a general way, we can (at least for now) group these layers into three broad categories, the (surface) mixed layer, the thermocline layer, and the deep waters. We will subdivide the intermediate and deep layers when we discuss the global ocean conveyor belt in the coming weeks.


©Copyright 1999
March 13, 1999

Send to Don Reed

Department of Geology
San Jose State University

Pointer Icon On to a recent study of ocean temperature