Now that you know how to run a CTD and how it works, what about the data it collects? This figure is more or less what I see on my screen while the CTD is in the water.
There are four x-axes: fluorometer (remember, that records the microscopic plants), salinity, temperature, and oxygen. Having all four on one graph means that I can keep track of lots of different variables at once.
What do you notice about this graph? I notice that below 40m, temperature and oxygen vary inversely - when one gets bigger, the other gets smaller. I also notice that at around 140m, it gets warmer very suddenly. I can also see that the maximum fluorescence is at 15m, so I bet the biologists will want a sample of the water there.
This graph only shows the top 200m, but the CTD actually went down to 600 m at this location. It's in a place called Hughes Bay on the western side of the Antarctic Peninsula. And there's something special about this cast, something that makes it different from all the other casts. Can you guess what it is?