Ocean Acidification Lab Part II: Shells Protocol
Central Question:
How does a decrease in the pH of seawater affect the calcium carbonate shells of animals?
Overview of Experiment:
Shelled organisms that create calcium carbonate skeletons are threatened by the drop in ocean pH (rise in ocean acidity) related to increased atmospheric carbon dioxide levels. Increasing acidity/lowered pH in ocean water not only causes the shells to dissolve, but it reduces the availability of carbonate ions – which animals use to build their shells and skeletons.
Ca 2+ + CO3 2- -> CaCO3
Calcium + Carbonate -> Calcium Carbonate
You will observe the effect of an acidic environment on mussel shells through observations and measurements.
Student Pre- lab Questions:
1. How do organisms make their shells? What are shells made of?
Some shell builders, such as crabs, shrimp and lobsters, unexpectedly build more shell when exposed to ocean acidification. When carbon dioxide (CO2) is absorbed by seawater, chemical reactions occur that reduce seawater pH, carbonate ion concentration, and saturation states of biologically important calcium carbonate minerals. These chemical reactions are termed "ocean acidification" or "OA" for short. Calcium carbonate minerals are the building blocks for the skeletons and shells of many marine organisms.
2. What do you expect to happen to the shell in an acidic solution such as vinegar?
I expect it to deteriorate, also known as disintegrating.
3. What are sources of carbon dioxide and which of these sources are most likely to affect ocean pH?
Car fuels burning is one source that causes this and because of it, the carbon dioxide is pulled into the ocean changing the acidity in the ocean waters.
How does a decrease in the pH of seawater affect the calcium carbonate shells of animals?
Overview of Experiment:
Shelled organisms that create calcium carbonate skeletons are threatened by the drop in ocean pH (rise in ocean acidity) related to increased atmospheric carbon dioxide levels. Increasing acidity/lowered pH in ocean water not only causes the shells to dissolve, but it reduces the availability of carbonate ions – which animals use to build their shells and skeletons.
Ca 2+ + CO3 2- -> CaCO3
Calcium + Carbonate -> Calcium Carbonate
You will observe the effect of an acidic environment on mussel shells through observations and measurements.
Student Pre- lab Questions:
1. How do organisms make their shells? What are shells made of?
Some shell builders, such as crabs, shrimp and lobsters, unexpectedly build more shell when exposed to ocean acidification. When carbon dioxide (CO2) is absorbed by seawater, chemical reactions occur that reduce seawater pH, carbonate ion concentration, and saturation states of biologically important calcium carbonate minerals. These chemical reactions are termed "ocean acidification" or "OA" for short. Calcium carbonate minerals are the building blocks for the skeletons and shells of many marine organisms.
2. What do you expect to happen to the shell in an acidic solution such as vinegar?
I expect it to deteriorate, also known as disintegrating.
3. What are sources of carbon dioxide and which of these sources are most likely to affect ocean pH?
Car fuels burning is one source that causes this and because of it, the carbon dioxide is pulled into the ocean changing the acidity in the ocean waters.
Hypothesis:
If we put the shells in a acidic environment, then the shells will weaken and nearly disintegrate.
Material Checklist
___ (4) shells (2 untreated and 2 pre-treated in vinegar) ___ (1) tweezer
___ 150 mL vinegar ___ (3) paper towels
___ 150 mL salt water ___ (1) sharpie
___ (1) beaker ___ (1) timer
If we put the shells in a acidic environment, then the shells will weaken and nearly disintegrate.
Material Checklist
___ (4) shells (2 untreated and 2 pre-treated in vinegar) ___ (1) tweezer
___ 150 mL vinegar ___ (3) paper towels
___ 150 mL salt water ___ (1) sharpie
___ (1) beaker ___ (1) timer
Analysis/Discussion of Data
1. When you immersed the shells in vinegar how did you know that a reaction was
happening?
When we put the shells in our acidic substances we noticed that C was bubbling like crazy and that gave us a sign that a reaction was happening.
2. How did observing the shells in vinegar relate to how animals are affected by a lower pH of ocean water?
Just as the shells were bubbly and disintegrating, the animal's tissues and sins dissolve in the acid just as if you were to pour bleach on your hand, it burns and irritates, same as the marine animals.
3. How would shelled organisms be affected by a lower pH of ocean water?
Young fish and immature stages of aquatic insects are extremely sensitive to pH levels below 5 and may die at these low pH values. High pH levels (9-14) can harm fish by denaturing cellular membranes. Low pH levels accelerate the release of metals from rocks or sediments in the stream. These metals can affect a fish’s metabolism and the fish’s ability to take water in through the gills, and can kill fish fry.
4. What are the primary functions of shell for these animals?
It is to protect, defend, and hide in. Protect and defend from predators and hide in case the shells won't have much effect.
5. Does it cost the animal energy to rebuild or repair their shell?
Yes because it can take days fr the animals to repair their shells and they don't have long arms or hands to assist them, they have to use other difficult ways to do it and it takes a lot of work for them.
1. When you immersed the shells in vinegar how did you know that a reaction was
happening?
When we put the shells in our acidic substances we noticed that C was bubbling like crazy and that gave us a sign that a reaction was happening.
2. How did observing the shells in vinegar relate to how animals are affected by a lower pH of ocean water?
Just as the shells were bubbly and disintegrating, the animal's tissues and sins dissolve in the acid just as if you were to pour bleach on your hand, it burns and irritates, same as the marine animals.
3. How would shelled organisms be affected by a lower pH of ocean water?
Young fish and immature stages of aquatic insects are extremely sensitive to pH levels below 5 and may die at these low pH values. High pH levels (9-14) can harm fish by denaturing cellular membranes. Low pH levels accelerate the release of metals from rocks or sediments in the stream. These metals can affect a fish’s metabolism and the fish’s ability to take water in through the gills, and can kill fish fry.
4. What are the primary functions of shell for these animals?
It is to protect, defend, and hide in. Protect and defend from predators and hide in case the shells won't have much effect.
5. Does it cost the animal energy to rebuild or repair their shell?
Yes because it can take days fr the animals to repair their shells and they don't have long arms or hands to assist them, they have to use other difficult ways to do it and it takes a lot of work for them.
