One of the advantages of deep CTD casts - an ability to make souvenir styrofoam cups. We design normal size white cups, tie it to the rosette going down to a significant depth and they get compressed by pressure. Here's an example of the cups I designed the other day, when we did a 1500 m cast as a SOCCOM float calibration.
I drew different activities we do on board - launching radiosondes, doing oceanographic stations with a rosette and plankton nets we drag after a slow moving ship to collect plankton and microplastics samples.
We one had only a few cups this time, I am hoping to stock up in Hobart and design more souvenirs during the upcoming legs of the ACE.