## Lab 8.3 – Can wind direction data help us synthesize our observation from Activity 1 and 2?

Estimated time to complete: 45 minutes
Materials needed: None

In the previous two activities, we examined DO and seawater temperature and identified patterns of how they correlate with each other. By this point you probably have formulated some hypotheses as to what is happening to kill the crabs. In this activity we will add a third variable, northward wind direction speed. We will try to synthesize all of our observations to make a comprehensive hypothesis to explain why the crabs died.

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 zoom in and out of areas of the graph using the slider bar. Note that the wind data shows only that part of the wind parallel to shore. Positive values indicate wind blowing toward the north, negative values toward the south.

### Interpretation Questions

1. Do you see any correlation between wind direction and dissolved oxygen? If so, characterize the relationship.
2. Do you see any correlation between wind direction and temperature? If so, characterize the relationship.
3. Summarize what happened with all three variables over the course of the study interval in a general sort of way. When one variable changed, how did the other variables change? Were the changes predictable?
4. What mechanism can you think of that could cause the wind direction to influence both DO and T simultaneously?
5. What killed the crabs and what was the sequence of events that caused it to happen?

### Assessment Question

1. Can we use our understanding of this scenario to help predict when this crab-killing sequence of events might happen in the future in this area? What types of conditions would you need to look out for?

### Reflection Questions

1. How are different marine organisms affected by these events?
• Are some more vulnerable than others?
• Which populations are especially vulnerable to long term population decreases, and which recover more quickly?
2. In the wake of anoxic events, should humans enact regulations to help marine populations recover?

### Real World Application

People depend on seafood as part of their diets, especially in coastal communities. These events can have an economic impact on these communities.