## Lab 8.2 – How do DO levels correlate to seawater temperatures?

Estimated time to complete: 45 minutes
Materials needed: None

In this activity we will add a new data set collected over the same time at the same place, seawater temperature. We will look for patterns in how these two data sets may correlate with each other.

Use the graph to answer the following questions. When you hover over a data point, a box will pop up with more information. You can turn zoom and out of areas of the graph using the slider bar.

### Interpretation Questions

1. How many periods of prolonged low temperatures (more than a few hours) do you see in this data?
2. Compare the two interactive graphs. What do you notice about the trends in temperature and DO?
3. Does DO change at the same pace (rapid or slow) as the seawater temperature?
4. What do you know about the relationship between temperature and dissolved oxygen?
5. Does the pattern shown in the graphs fit the relationship you described in the previous question? Explain.

### Application Questions

1. In a general way, where in the ocean do you expect colder water to occur, and where in the ocean do you expect warmer water?
2. The following figure shows us seawater temperature along a transect across the shelf by Endurance Glider #384, near our study area. The colors represent different temperatures. The seawater temperature data we are examining was collected in approximately 25m of water. According to this profile, what is the expected approximate temperature of seawater off the Oregon coast at 25m?

1. According to the figure above, at what approximate depths would we usually find water at the temperature range we see in our minimum temperatures for our 25m study site?
2. Formulate a hypothesis as to why the seawater is changing temperature and dissolved oxygen content in the pattern observed here. What other sorts of data might be needed to test your hypothesis?