Question

location ph 1 ph 2 mean ph color co₂ levels willapa bay 4.94 4.84 yellow south slough 6.5 6.55 green sitka tribe 8.18 8.28 blue ketchikan, alaska 8.27 8.29 blue point conception 8.3 8.34 blue la push, oregon 8.4 8.46 blue 1. draw a bar graph using the data you collected. make sure the graph has labels and titles for both axes! color each bar yellow, blue, or green to reflect the level of co₂ detected using btb. the grid is 20 x 20. 2. identify the area/s that have the lowest ph levels. 3. based on what you have learned about ocean ph, identify the area/s you tested that have ph values within the ideal range for urchins. 4. identify the area/s that have the highest co₂ levels.

Explanation:

Sub - question 2

Step 1: Calculate the mean pH for each location

• For Willapa Bay: The two pH values are 4.94 and 4.84. The mean pH is calculated as $\frac{4.94 + 4.84}{2}=\frac{9.78}{2} = 4.89$.
• For South Slough: The two pH values are 6.5 and 6.55. The mean pH is $\frac{6.5+6.55}{2}=\frac{13.05}{2}=6.525$.
• For Sitka Tribe: The two pH values are 8.18 and 8.28. The mean pH is $\frac{8.18 + 8.28}{2}=\frac{16.46}{2}=8.23$.
• For Ketchikan, Alaska: The two pH values are 8.27 and 8.29. The mean pH is $\frac{8.27+8.29}{2}=\frac{16.56}{2}=8.28$.
• For Point Conception: The two pH values are 8.3 and 8.34. The mean pH is $\frac{8.3 + 8.34}{2}=\frac{16.64}{2}=8.32$.
• For La Push, Oregon: The two pH values are 8.4 and 8.46. The mean pH is $\frac{8.4+8.46}{2}=\frac{16.86}{2}=8.43$.

Step 2: Compare the mean pH values

We compare the mean pH values: 4.89 (Willapa Bay), 6.525 (South Slough), 8.23 (Sitka Tribe), 8.28 (Ketchikan, Alaska), 8.32 (Point Conception), 8.43 (La Push, Oregon). The lowest value is 4.89 which corresponds to Willapa Bay.

Step 1: Recall the relationship between pH and $CO_2$ in water

In water, a lower pH is associated with higher levels of dissolved $CO_2$ (because $CO_2$ dissolves in water to form carbonic acid, $H_2CO_3$, which lowers the pH).

Step 2: Identify the location with the lowest pH

From sub - question 2, we know that Willapa Bay has the lowest pH. Since lower pH means higher $CO_2$ levels (due to the formation of carbonic acid from dissolved $CO_2$), the area with the highest $CO_2$ levels is the one with the lowest pH.

Answer:

Willapa Bay

Sub - question 4