September 18- shrinking Styrofoam cups
After a five-day break due to the ice stations, only a few CTD casts were done, but we are now back in full force. This afternoon’s (even though it is pitch black outside) cast had special cargo onboard- Styrofoam cups. Two hundred cups were decorated by Watershed School (Fairbanks, Alaska) students and staff, and another 20 were decorated by expedition members. There is an ongoing tradition among oceanographic expedition members to decorate and submerge Styrofoam cups into deep oceanic water. The outcome is amazing because the cups shrink.
Styrofoam cups are made of beads from a type of plastic called polystyrene, and the beads are puffed up with air. During descents into the ocean, the accumulated weight of water increases and pressure builds up – about 14.7 pounds per square inch for every 33 feet (10 m) of depth. As pressure mounts, it squeezes the air out of Styrofoam objects, Capt. Mark Wetzler, commanding officer of the National Oceanographic and Atmospheric Administration (NOAA) research ship Okeanos Explorer, wrote in a mission log in 2017. (www.livescience.com)
But, one of the really neat things is that even though the pressure is the same, the cup’s air bubbles aren’t the same size. It is a mystery as to how the cups will turn out. They all have their own unique shapes. When the cups come out of the water, it’s like unwrapping little gifts to see how each one came out.
We borrowed PhD student Channing Bolt’s NEMO mesh laundry bag and loaded it with Styrofoam cups loosely stuffed with paper towels. The paper towels help the cups keep their shape and prevent them from stacking on and sticking to each other. It took three different casts to get all of the cups done. We chose three of our deepest mid-cruise casts. The cast has to be deep enough for the cups to shrink, but not too deep because the cups will implode and fall apart. Our casts were all around 3,000 meters. Today, the cups traveled down to 2,640 meters. This was a special cast because, like a lot of the scheduling this cruise, the cast was changed to an earlier time. I had to run to my cabin, grab the bag, go to the lab, and thank goodness Chemical Oceanographer Matt Alkire was there, otherwise the cups wouldn’t have made it on to the rosette. On several casts, Matt took off a few Niskin bottles and tied down the mesh bag. Thank you, Matt, for saving the day!
Breakfast: porridge, meat and cheese
Lunch: borsch soup, fried cod, and baked cauliflower/broccoli
Tea Time: crab salad
Dinner: baked turkey and spaghetti