Ocean Acidification Lab
Title: The effects of composition of water on the absorption of Carbon Dioxide.
Topic Introduction: The Ocean provides us with many uses and ways to help us
live, breathe, obtain food... you name it. But what we haven't yet realized is
how little we are giving it back for its service to us. In this case, it is more like
how much more we are giving it than it can handle. We already know that the
ocean absorbs 25% of the ocean's CO2 levels, but what we are barely figuring
out is that we are giving it more carbon dioxide making this more harmful to all
of marine life. Over the last 250 years, the amount of CO2 has increased by
30% make the water more acidic than it has ever been. When Carbon Dioxide
mixes with water, an acid is created known as H2CO3, or in other words;
Carbonic Acid. With the high amounts of CO2 building up in the water, this
affects shellfish in making their shells because they use an element in the
water known as calcium, that is being mixed with CO3 making calcium
Carbonate. This element lessens the ability for these creatures to make their
shells making them an easy prey for other predators.
Experimental Question: What happens to water when it absorbs high amounts
of Carbon Dioxide?
Bubbles Protocol
Hypothesis: If air is blown into the seawater, then the sea water would turn
acidic due to the levels of carbon dioxide.
Pre-Lab Questions:
1. What gas are you blowing into the water?
The gas being blown into the water is Carbon Dioxide.
2. What happens to the gas when you blow it into the water?
The gas is being the absorbed by the water
3. How are you measuring change in the water during this lab?
The change of the water is being measured by the measured by it's change in
color. There's a pH indicator liquid that is added to the water.
4. What does measuring the pH of the water tell us?
This tells us the acidity level of the water.
5. After studying the reactions above, how do you think carbonic acid will affect
the pH of saltwater?
The Carbon Acid will cause the salt water's pH to become acidic.
Hypothesis: Bubbles Protocol
If carbon dioxide bubbles are added to the sea water, then the pH level of the
water will become more acidic due to the pH scale.
Protocol:
Preparation
1. Assign a role to each group member
2. Familiarize yourself with the Universal Indicator Color Chart
Control Trial:
1. MATERIALS: Add 100 mL saltwater to a 500 ml beaker.
2. MATERIALS: Using your transfer pipet, add 4 drops of universal indicator.
(Save your pipet for your next experiment!)
3. MATERIALS: Place a white sheet of paper under the beaker and record the
initial color using the table on the data sheet.
4. MATERIALS: Stretch the piece of parafilm or saran wrap to completely cover
the top of the beaker – then insert the straw by poking a hole through the
parafilm.
5. RECORDER: Get the data sheet and prepare to record the color of the
solution every 30 seconds, using the colors listed on the Universal Indicator
Color Chart.
6. TIMER: Get timer ready to record for TWO MINUTES - Begin timing AT THE
SAME TIME as breather begins blowing.
BREATHER: Begin blowing through the straw into the water at exactly the
same time as the
timer begins timing. Breathe at a steady rate, exhaling only through straw. (Be
careful to not
inhale or suck on the straw!)
7. TIMER: Call out 30 second intervals.
RECORDER: As the timer calls out each 30 second interval, record the color at
that time using the same color descriptions as the Universal Indicator Color
Chart.
BREATHER: Exhale/blow at steady breathing rate for two full minutes.
8. RECORDER: Using the table on your data sheet and the Universal Indicator
Color Chart,
convert your color data to numbers, plot your data on the graph provided, and
draw a line
connecting the points to create a line graph.
9. GROUP: Decide on how you want to experiment by changing the variables.
You will choose
Protocol A, Protocol B, or Protocol C
Data Table
Graph
:
Data Analysis:
1. As you blew through the straw, what were you adding to the water and how
did that change the pH?
Carbon Dioxide was being added to the water. The pH of the water was affected
as it started to become more acidic.
2. What did the universal indicator tell us about the water?
The universal indicator told us the pH of the water.
3. What does this tell us about the effects of carbonic acid in ocean water?
This tells us that when the carbonic acid is placed in the ocean water it slowly
turns more acidic.
4. Based on the results of your experimental protocol, which factor affects the
pH of the water most, temperature or salt?
From what the data showed us, the temperature affected the pH of the water
the most.
Conclusion:
My hypothesis was had supported data from the graph and data table
shown. I stated that the more carbon dioxide put into the water/ beaker, the
more acidic it would become. This proved my hypothesis to be correct and
showed that the more carbon dioxide put into ocean water, the higher levels in
pH value will rise due to our universal indicator. But even though this
experimental trial was put to a small test, these changes are actually being
made all around the globe. The only defect we have is not being able to realize
how quickly these changes are affecting us all. Hopefully, we should all be able
to see just how these changes we are making on the environment are affecting
us all today.
-------------------------------------------------------------------------------Shell Protocol
Hypothesis: If shells are put into vinegar instead of sea water, then their shells
will start to dissolve much faster. The acidity level of vinegar is much stronger
than sea water and adds more carbon dioxide to the shell, making them unable
to produce their shells faster than they are deteriorating.
Protocol:
1. MATERIALS: Remove your two untreated shells from their bags.
2. MATERIALS: With a sharpie, label one shell “E’ for experimental and one
shell “C” for control.
3. RECORDER: Using your data table record your group’s initial observations
of the control and experimental shell characteristics.
4. MATERIALS: Find the mass of each of the shells.
5. RECORDER: Record the starting masses of both shells on your data table.
6. MEASURING: Pour 150 ml of vinegar into a 500 ml beaker and 150 ml of
salt water into a second 500ml beaker.
7. TIMER: Set the timer for 30 min.
8. MATERIALS: At the same time: Add the untreated, control shell “C” shell to
salt water and the untreated, experimental shell “E” to the beaker of vinegar
and start the timer.
9. RECORDER: In your data table, observe and record your group’s
observations of what is happening to the shell while exposed to the vinegar over
time. (at 0 minutes and 15 minutes)
10. ***EVERYONE: Between observations of your shell in acid (vinegar), spend
time observing and recording observations of shell characteristics for the
pretreated (“Low Exposure” and “High Exposure”) shells.
11.MATERIALS: After 30min use the tweezers to remove the shell from the
vinegar and place on a paper towel. Dry the shell with a paper towel as best as
you can.
12.MEASURING: Find the mass of both the control and the experimental
shells.
13.RECORDER: Record the final masses and observations of the experimental
and control shells after treatment.
14.EVERYONE: Decide how to test the strength of the shell. Options are:
a. Test the shell strength by dropping the shell from a height of 5 feet from the
ground and then record the damage or breakage on your data table
b. Break the shell with textbooks to see how easily the shells break
Data Table
Graph
Data Analysis:
1. When you immersed the shells in vinegar how did you know that a reaction
was happening?
I knew there was a chemical reaction occurring when bubbles started to
emerge from the shell. I knew this effect was caused due to the reaction of
carbon dioxide.
2. How did observing the shells in vinegar relate to how animals are affected by
a lower pH of ocean water?
In the lab, the vinegar represented ocean acidity and the shell represented
them all in the entire ocean. We can see how this affects life in the ocean from
a global point of view.
3. How would shelled organisms be affected by a lower pH of ocean water?
The shells would dissolve at a increasing rate, making it harder for them to
regenerate.
4. What are the primary functions of shell for these animals?
The shell provides protection to the animal against predators, and serves as a
home.
5. Does it cost the animal energy to rebuild or repair their shell?
Recreating a new shell requires suing more molecules and energy to do so.
Conclusion:
The data shown above supported my hypothesis to be true. I had
hypothesized that If the shells were put into vinegar instead of sea water, then
their shells will start to dissolve much faster due to the acidity level of vinegar
being much stronger than sea water and adds more carbon dioxide to the shell,
making it unable to produce their shell faster than they are deteriorating.
When the shell was placed in regular sea water, its final mass had no change,
as to when the other shell was placed in vinegar; it started losing mass because
of the chemical reaction with the carbon dioxide causing the shell to dissolve
rapidly. This clearly shows from a global perspective how much these animals
are being affected and just how much of a difference this could cause to throw
the ecosystem out of balance.