Middle – MS-LS2-4 - Disruptions to any physical or biological component of an ecosystem can lead to shifts in all its populations.
- 2 Eggs
- 2 Clear glass jars
- 250 ml Tap water (1 cup)
- 50 ml Vinegar (1/5 cup)
- Scotch tape
Not all carbon dioxide emissions are contained in the Earth's atmosphere- some are absorbed by large bodies of water, including our oceans. As carbon dioxide dissolves into an ocean, the water’s pH level becomes more acidic. Oceans have become about 30% more acidic over the past 200 years. This is alarming because it is the most significant change in ocean chemistry ever noted.
Even though the ocean is immensely large, the large amount of carbon dioxide dissolving into it can have a direct impact on which marine species can survive and flourish there.One effect of a more acidic ocean is the loss of calcium carbonate (CaCO3). Certain marine species rely on calcium carbonate to build a shell or exoskeleton.
In this experiment we will use chicken eggs to represent the marine species that rely on calcium carbonate, because eggs are comprised of 94-97% calcium carbonate.
scotch tape on both jars and label one “Neutral”
and the other “Acidic”. These jars will be used to represent an acidic
oceanic environment (environment with a high pH balance) and a non-acidic
oceanic environment (environment with a neutral pH balance) for the eggs (which
represent a marine species relying on calcium carbonate).
100 ml of tap water and 50 ml of vinegar and add both to the jar labeled “Acidic”.
150 ml tap water and add to jar labeled “Neutral”.
place one egg into each of the jars so that the egg is completely submerged in
the liquid. Over a period of 72-hours, the shell of the egg in the acidic jar
will have dissolved and only the membrane will remain. The egg in the pH
neutral jar will have remained the same.
the 72-hour period students should make observations about the condition of
both the eggs. Students can use the chart found at the bottom of this lesson to
note observations of not only the appearance of the eggs, but also any
observations about the liquids contained in the jars.
to the students that acetic acid in vinegar dissolves the calcium carbonate
(CaCO3). When the acid in the vinegar reacts with the eggshell,
carbon dioxide is released in the form of bubbles. The chemical equation for
this process is H2O+CO2= H2CO3
the possible impacts on marine life.
Questions of Interest:
How does ocean acidification affect marine life relying on a shell or exoskeleton?
Does ocean acidification affect all marine life the same way?
How could the effects of ocean acidification be lessened or minimized?
What is the connection between ocean acidification connect and deforestation?
Does the idea of ocean acidification raise any other questions about how human activity might be affecting our planet?
Why is it important for us to study ocean acidification?
View the video clip: https://youtu.be/Wo-bHt1bOsw
Read “The Seattle (WA) Times” News Article: SEACHANGE-Oysters Dying As Coast Is Hit Hard: http://apps.seattletimes.com/reports/sea-change/2013/sep/11/oysters-hit-hard/
Read: “Garfield students share what they’ve learned about ocean acidification”. http://blogs.seattletimes.com/seachange/
View PowerPoint Presentation entitled “Ocean Acidification” in news article section, “Students at The Northwest School study ocean acidification”. http://blogs.seattletimes.com/seachange/
What is a “Food Chain”?
What does a “Marine Life Food Chain” look like?
If marine life affected by ocean acidification were to die, how would the “Marine Life Food Chain” be impacted?
If the “Marine Life Food Chain” is negatively impacted, how might that affect our food choices and economy?
Follow this link to download student worksheet.