## Lab 2.2 – Station profiles, how to read a standard oceanography graph

Fundamental concept: Variability in the data, finding trends
Estimated time to complete: 30 minutes
Materials needed (none)

### Is there structure to the water in the ocean?

Although ocean water looks much the same wherever you go, once you start to measure properties such as salinity and temperature you would see that there are considerable differences. A standard type of graph used to examine some of these differences is called a station profile. Typically these are graphs showing a data type such as temperature, salinity, or something else plotted against the depth of the water. Oceanographers make these graphs because many of the properties of seawater change with depth.

Figure 2.2.1

1. Can you speculate on why it is useful to make a station profile graph with this orientation?
2. Identify the maximum and minimum temperature values in this station profile graph from the Pioneer array, off the mid-Atlantic U.S. coast.
3. How does the temperature of the water change as you go deeper in the water?
4. The depth where the temperature changes the most rapidly is called the thermocline. At what depth is the thermocline in this profile?
5. North Atlantic fin whales migrate through the area of the Pioneer array. These whales breathe air at the surface and dive to feed on krill, squid and other prey. If a fin whale dove from the surface to 100 meters deep at the time and location that this profile was collected, how much change in temperature would it experience?

Now let’s also look at a temperature profile graph from the Irminger Sea array in the deep North Atlantic basin.

Figure 2.2.2

1. Identify the maximum and minimum temperature values in this station profile graph from the Irminger Sea (Figure 2.2.2). How does the temperature of the water change as you go deeper in the water?
2. Now compare the Pioneer and Irminger temperature profiles. How similar or different are these two station profiles?
3. Click the buttons in Figure 2.2.2 to match the depth and temperature scales. Did your answer to the previous question change when you did this?
4. Why do you think these two temperature profiles are so different? Look back at the location of these two arrays.

### Question for reflection

1. When comparing two or more data sets why is it important to compare the scales? Use an example from this station profile activity to support your answer.