Wednesday, March 4, 2009

Station 22

Life on a ship can be lots fun, but we also work very hard. By now you’re probably wondering what we do all day. Most of the time, we do CTD casts. CTD stands for conductivity (a measure of how salty the water is), temperature, and depth. We put the instrument package, which contains the CTD, LADCPs, and few other things, into the water on a very strong wire. Here’s a picture of the CTD on the package:

It’s the odd-looking thing in the middle of the pictures with all of the wires attached to it. You can see one of the LADCPs on the left.

Later, I’ll try to get a video of the deployment (when we put the package in the water) and recovery (when we take it out of the water). For now, I’m going to show you the data from a recent CTD station, number 22.

Normally we can’t distribute data from a cruise until two years after collection. Since we did the work, we get to publish our interpretations of the data first! However, the chief scientist of the cruise, Dr. Arnold Gordon, is letting you have the data early as long as you promise not to publish before he does.

Here’s a graph of the temperature data:

There’s a lot we can learn from this graph! First, look at the axes. What are the units? How big is the range? Look carefully at the y-axis and the direction in which numbers increase. Is this how we usually make graphs?

Once you know how the graph is structured, you can start working with the data. What happens to the temperature as you go deeper in the water? Does it increase? Decrease? How quickly does the temperature change with depth? Why does the temperature change in this pattern?

Remember, this is the temperature during one cast. Would we get different results if we tried it again? What about a cast nearby – would the results look the same? There are a lot of questions you can ask about these data. Let me know what questions you want to answer, and I’ll try to supply the data that you need.


  1. Hi Ms. T!
    It's the 6th grade science club! We have had a crazy week! We had a snow day on Monday and now we're preparing for final exams! How are you at sea? Irving wants to know if you are sea sick. Daniella would like to know if you're eating a lot of fish. Bryan, Nachary, and Andrea are curious about their styrafoam cups (could you take pictures of them when you tie them and put them under?) Shaina would like to if you've seen any sharks!
    Today in science club we were experimenting with air pressure and made our own barometers - although we are too smart and it went really fast. We are talking about density in science class right now - what can you tell us about the density of ocean water? Is it tied to salinity at all?
    anywho - hope you are well and not getting sunburned!
    -Science club!

  2. ooh ps,
    Ms. Brooks and her students will be online during class tomorrow. The blog looks great!