Name___________________
Period________________
Ocean Acidification Practice:
Carbon dioxide, which is naturally in the atmosphere, dissolves into seawater. Water
and carbon dioxide combine to form carbonic acid (H2CO3), a weak acid that breaks
(or “dissociates”) into hydrogen ions (H+) and bicarbonate ions (HCO3-).
Because of human-driven increased levels of carbon dioxide in the atmosphere, there
is more CO2 dissolving into the ocean. The ocean’s average pH is now around 8.1,
which is basic (or alkaline), but as the ocean continues to absorb more CO 2, the pH
decreases and the ocean becomes more acidic.
Instructions
Acid breath experiment
1)fill around ¼ of the container with clear water
2)add a drop of the bromothymol indicator
3) observe the color of the solution
4) take a straw and blow through the solution
5)what gas is expelled by our breath? _________________
5)what happened on the solution? _________________
6) discard the solution on the sink
7) repeat the process but add salt to the solution before blowing?
What changes did you observe?
___________________________________________
The change was slower or faster?_____________
8) what does this represent on the CO2 pollution on the atmosphere?
9) what effect do you think CO2 has on the oceans?
10) discard the solution on the sink
11) repeat the process but using warm water for the solution before blowing?
What changes did you observe?
___________________________________________
The change was slower or faster?_____________
Explanation:
Corals and fish can be affected by slight changes in the temperature of
the water and the next experiment also shows the effect of temperature
increase on CO2 absorption, creating a positive feedback, a knock-on
effect.
Eggshell experiment
Corals and shellfish can be affected by ocean acidification, making it
harder to create their shells, which will affect other fish up through the
food web.
Instructions:
1) Take a sample of eggshell (this will be an imitation of seashells)
2) Rinse it with the vinegar solution (low acidic ocean)
3) Observe what happens
Is it firmer or more brittle?_________________________
4) Place it on the vinegar solution (high acidic ocean)
5) Observe that happens
What happened after you placed the eggshell?
What difference made from just rinsing it?
What happened after you stirred the solution with the eggshell?
What do you think happens to seashells on the ocean as it becomes more acidic?