Under pressure

Deep CTD cast on 6.19.2013.

Station Aloha is approximately 4800 meters deep.  During the research cruise we took 2 CTD casts from the surface waters down to the very bottom.  The deep ocean water is cold and salty making it very dense.  At the surface the water is a balmy 25 degrees Celsius (77 degrees Fahrenheit) while at depth it is near freezing temperatures!  The deep waters also have high oxygen because the deep ocean water comes from the cold, oxygen-rich deep waters from the poles.  The water is transported by large ocean currents that connect all oceans.  This is called thermohaline circulation.  The movement of water is driven by density differences and is sometimes described as the "great ocean conveyer belt".  

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Our decorated styrofoam cups after being sent down with the CTD. They were squished to about a quarter of their original size under the pressure of being 3 miles under the sea!