# 10 Calculate the amount of carbon released from coastal erosion

** **

Step 1

From the ImageJ tools select the Segmented Lines tool. Right click (on a PC) or Command click (on a Mac) to select the Segmented Lines option.

Step 2

Zoom into an area that has been heavily eroded. Use the segmented line tool to click along the coastline that was still there in 1985. Without moving the mouse, double click to end the line. To delete a line, click on the image to make it disappear. The nodes, or vertexes, can be moved by clicking and dragging.

Step 3

From the ImageJ menu select Analyze → Measure.

Step 4

In the Results window, the length of the segmented line will be in meters.
In this example, the length of the section along the coast that has been lost to erosion is about 4100 meters. Convert the meters to kilometers.

- Roll-over for Hint 1:
- Divide the results by 1000 to convert meters to kilometers.

**Answer:**

4.1 Kilometers

**Step 5**

From fieldwork conducted in this area, scientists have determined that the amount of carbon input from the North Cape Halkett coastline is 605 Mg/km/yr, as mentioned above. A Mg, or megagram, is a metric ton.

Multiply the length (in km) x 605 to find the amount of carbon released in one year (in Mg/yr).

In this example, 4.1km x 605 Mg/km/yr = 2,480.5 Mg/yr** **

**Making Sense of the Number**

How much carbon has been released, a little or a lot? How many railroad cars would it take to hold that amount of carbon?

One railroad train car carries approximately 105 tons of coal. There is more than one way to figure out how many railroad cars it would take to haul the carbon released from this area of Cape Halkett.

One way is to use Google to convert tons to metric tons: 105 tons is equal to 95.25 metric tons. So, one train car carries about 95.25 metric tons of coal. To figure out how many total cars are needed, divide 2541Mg / 95.25 Mg per railroad car = 26.6 railroad cars. Twenty six railroad cars full of coal weigh as much as the carbon released.