On every cruise, it’s tradition to send decorated Styrofoam cups down on one of the instruments to shrink them.  Styrofoam is mostly air, so when cups made of Styrofoam are sent to the depths, as the pressure increases with depth, the air inside the cups is compressed, and the cups shrink accordingly.  Once they shrink, they stay that way, as Styrofoam isn’t particularly flexible – it doesn’t expand again when it comes to the surface.  This year, we received a set of beautifully decorated cups from Theresa McCaffrey’s Advanced Art Classes at Tualatin High School.  Ruth Musgraves, who developed and runs our Creep into the DEEPEND summer camps (http://whaletimes.org/?p=2186) has a daughter in one of these art classes, and they heard about the shrinking cups through her.  They send out a box of cups, and the artwork is quite amazing, as you can see in the photos below.   The best part is that they made some cups for us as well.

I’m really thrilled about that, because I’m pretty much still at the stick figure level when it comes to my artistic endeavors.

 

There is a pretty careful protocol that we must follow to package the cups, so that the cups shrink without collapsing inside of each other as they shrink at different rates.  If two cups shrink together, one inside of the other, they’re almost impossible to get apart without breaking one.  They must be loaded in mesh bags with open ends facing each other, with each row separated by tie wraps so they don’t float together and collapse together. 

We can load 14 cups per bag, and two bags per CTD rosette.   The CTD rosette is deployed to collect water samples at various depths, monitoring conductivity (C – as a measurement of salinity) and temperature (T) as a function of depth (D).  We have to be careful that the bags do not interfere with any of the sensors or closing mechanisms on the bottles, so we never load more than two  bags per deployment.

We had just finished shrinking all the cups, and the CTD was down, cupless this time, when a squall came through, and 10 foot swells came along with it.  The CTD had to be brought to the surface immediately, and it was quite a dangerous recovery trying to keep the CTD from swinging like a pendulum with safety lines.  As you can see, the cups are just attached by tie wraps, and in those seas, the bag might have snapped off or cups damaged when the protective frame around the rosette was pulled next to the ship to prevent swinging.   We lucked out on that one!