13 Aug 2012

CCE LTER Cruise: Day 14, Shrunken Cups

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Written by Dana Lebental, Teacher at Sea

August 10- Day 14

Chemistry Lesson of the Day: 

Boyle’s Law states that if you increase the pressure

you will decrease the volume.


I’m a chemistry teacher, what can I say. I wanted to see Boyle’s Law in action. My idea was that if I take three different types/sizes of cup and lower them into the ocean, where the pressure is greater than on land, the the cups should shrink (less volume).

August 10, 2012, 2:00 am, I started Day 14 at sea. This was a big day, I finally received permission to attach my Styrofoam cups and heads to the CTD (Conductivity, Temperature and Depth Instrument) a device that we were going to lower 2,000 meters (6,600 feet or 5 laps around the running track) below the surface of the water.


Styrofoam Cups

Preparing for Deployment

Before I left, Centennial High School students, Compton High School students and Cabrillo Marine Aquarium Jr. Docents all decorated these cups for me.

Three Schools

Three Different Cups

To prepare these cups for deployment I carefully placed a piece of tape over the tops, so none of the cups would get eaten or stuck in another cup. Then I carefully placed them into mesh laundry bags to attach to the CTD.

Styrofoam Cups Being Lowered over Ship

Styrofoam Cups Being Lowered over Ship

After the CTD was in the water, I quickly ran inside to watch the monitor. I was anxious to have the CTD back on the deck of the ship. I’ve never deployed cups before, I didn’t know if this would work. And if it worked, how small would the cups be when they came back?

CTD Reader

Shows the depth and speed of the CTD

From inside we are able to monitor the speed the CTD goes down and the amount of wire out on the winch.

Senor Readings

Sensors on the CTD measure Dissolved Oxygen, Salinity, Temperature and few other things.

Once we hit 2,000 m it was time to send the CTD back to surface. The majority of the cast we went down at 60 meters per minute (MPM), which took us over 30 minutes to go down and now I had to wait another 30 minute until it reached the surface.

This is what we saw…


shrunken cups

When deploying the CTD, there was a hugh spike at around 1500 m on the fluorometer, a machine that sends out a light to see how much life (plankton or animals) are in the water, this spike could have represented a giant squid that attacked our cups due to the brightly colored designs in the bags.

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