Deadly Spill
Analyze categorical data to see the most immediate effects of the Deepwater Horizon oil spill on wildlife.
Background:
The Gulf of Mexico is recognized as one of the most economically and ecologically important ecosystems in all of North America. Home to countless corals, whales, fish, dolphins, sea turtles, and bird species, it provides many resources to the surrounding US states and Mexico.
On April 20, 2010 an explosion rocked BP’s Deepwater Horizon oil drilling platform and large amounts of crude oil began spilling into the Gulf of Mexico. With this, the wildlife in the area became immediately threatened. Relying on waterproofing of their feathers to keep them warm and buoyant, birds found themselves trying to preen oil coated feathers, ingesting the pollutant and struggling to maintain body temperature. Sea turtles and dolphins were immersed in oil, directly inhaling the oil or ingesting food covered in it. Turtle eggs also suffered from oil washed up on beaches, decreasing hatching rates or creating polluted environments where females couldn’t return to lay their eggs.
Researchers from across the country and around the world hurried to monitor the wildlife in the Gulf of Mexico. They patrolled the waters and the beaches, recording data for each individual animal encountered. In the first year following the oil spill, the researchers found and recorded data from more than 10,000 individual birds, sea turtles, and dolphins. They recorded if animals were found alive or dead, and if there was visible oil on their bodies. With these data, scientists were able to get a better picture of the extent of the damage to wildlife in the gulf. How many birds, turtles, and marine mammals were affected?
In this activity, explore different categorical data on the wildlife counted during the first year after the spill. Investigate the effects that the oil spill had on wildlife in different locations using real data from researchers there at the scene.
Dataset
This dataset was sourced from the Deepwater Horizon Response Consolidated Fish and Wildlife Collection Report. The report covers bird counts from the date of the oil spill (April 20, 2010) through April 14th, 2011 and marine mammals and sea turtles through April 12th, 2011 located in the impacted area. While these counts can inform us about the impact of the Deepwater Horizon oil spill, not all deaths are due to the oil spill, and not all deaths due to the oil spill are included in these data.
Each animal was given a specific numerical tag once surveyed, so that it would not be counted twice. Each row in the dataset corresponds to an individual animal recovered alive or dead.
You can see the original Deepwater Horizon Response Consolidated Fish and Wildlife Collection Report with summary data here. Data listed as “pending” in the original report were not included in this dataset.
Variables
Animal Type - This categorical variable describes the type of wildlife encountered. Values include bird, turtle, and mammal (which includes whales and dolphins).
Oil Status - This categorical variable describes if oil was found on the animal. Values include oiled, and no visible oil.
Collection Status - This categorical variable indicates if the animal was found alive or dead. Values include alive and dead.
Location - This categorical variable indicates the location in which the animal was found. If animals were found in the Gulf of Mexico, they are listed as Off-Shore. Values include Alabama, Florida, Louisiana, Mississippi, Texas, Unrecorded, and Off-Shore.
Activity
PART 1 - Explore the Dataset
Click on the Table tab to view the data table. Exactly how many individual animals are included in this dataset?
Click on the Graph tab to make a graph. Click the pie chart icon on the right control panel:
Now show Location as your x-variable. Use the camera icon to screenshot and paste your graph (pie chart) below:
3. What do you notice about this data (referencing the graph from #2)? Which location were the most animals recovered from?
4. Make a new pie chart showing the number of individuals of each Animal Type sampled. Copy and paste your graph (pie chart) below:
5. What might explain the difference in numbers between the three animal types included in this dataset (referencing the graph from #4)?
6. Were most of the animals found alive or dead? Make a new pie chart showing the number of individuals of each Collection Status sampled as evidence for your answer.
7. Why do you think the researchers found more animals dead than alive? (reference the graph from #5)?
PART 2 - Going Deeper (Exploring 2 Variables)
All of these graphs will be made with rectangles. Be sure to choose the appropriate icon:
8. Make a graph of Oil Status as the x-variable and Collection Status as the z-variable. Use the Appearance menu to make a stacked bar graph and Stack as proportion to make the y-axis show percentage. Copy and paste your graph (stacked bar chart) below
9. How is Oil Status related to Collection Status? Looking at this graph, it could be said that being oiled seems to increase the chances of the animal being alive. Does this seem like a likely explanation in reality ? What might be another explanation for this pattern in the data?
10. What does it look like to take the same data but present it differently? Keep oil status as the x-variable and collection status as the z-variable. Now deselect Stack as a proportion so that it reads number on the y-axis. Screenshot your graph below.
11. Even though this is the exact same data as you presented in the graph in #8, it tells a slightly different story when presented this way. What might be a reason THIS graph would be more helpful in telling a story, over the graph from #8.
12. Make a graph of Location as the x-variable and Oil Status as the z-variable. Be sure to turn off the Stak as proportion option in the Appearance menu. Use the Copy and paste your graph (stacked bar chart) below.
13. Which location appears to have been the most affected by the oil spill?
14. Florida has a greater amount of gulf shoreline than any other state along the Gulf of Mexico. Why do you think that more Florida wildlife was not collected in this dataset?