1.Multiple sources contribute; CO2 is primary but not sole
cause
2.Excess nutrients cause eutrophication and dead zones
3.Human CO2 emissions and ocean pH: Burning fossil fuels increases atmospheric CO2, which dissolves into seawater and forms carbonic acid, directly lowering ocean pH and threatening marine ecosystems that depend on stable water chemistry.
[!] STUDY GUIDE: Big Ideas
Use to answer form questions!
1.Atmospheric CO2 dissolves in seawater to form carbonic
acid.
This lowers ocean pH, making water more acidic.
2.Small pH changes have massive effects. A 0.1 pH
drop = 26% more acidic (logarithmic scale).
3.Marine shells dissolve when pH drops below tolerance
thresholds.
Organisms with calcium carbonate shells are most vulnerable.
[#] KEY TERMS
Define in YOUR words
pH scale
Measures acidity (0-14)
Logarithmic
Each step = 10× change
Acidification
Process of becoming more acidic
Carbonic acid
CO2 + H2O → H2CO3
[?] THE PHENOMENON
Write BEFORE Hook form
Why is the ocean becoming more acidic?
Pteropod ("sea butterfly") shells collected today are thinner and
more fragile than shells from 50 years ago—some are dissolving while
the animals are still alive!
Your initial thinking:
[>] AFTER HOOK FORM
Reflect, then continue+2 pts
I learned that...
Station 1 — CO2 & pH
When CO2 dissolves...
The pH changes because...
Key insight:
Station 2 — Shell Data
As pH decreases, shells...
This affects organisms by...
Key insight:
[/] DAY 1 EXIT TICKET
Complete before leaving+5 pts
Q1:
What gas is increasing in the atmosphere AND dissolving in oceans?
Q2:
From Cycle 3: Are carbon atoms created, destroyed, or conserved when
CO2 dissolves in water?
Confidence:
Ocean Acidification Investigation (continued)
Name:
[=]Day 2 start
Station 3 — Ecosystem Impacts
Organisms most affected are...
The food web is disrupted because...
One potential solution is...
Key insight:
[+] MAKING CONNECTIONS
Use for Exit Ticket!
How does atmospheric CO2 affect both heat trapping AND ocean
chemistry?
Where do the carbon atoms go when CO2 dissolves in seawater?
(Conservation of mass)
[/] DAY 2 EXIT TICKET
Final check before Science Circle+5 pts
Q1 (NEW):
Explain the chemical mechanism: CO2 + H2O → H2CO3. How does this
affect pH?
Q2 (SPIRAL):
How does atmospheric CO2 affect both heat trapping AND ocean
chemistry?
Q3 (INTEGRATION):
How do atmospheric and oceanic changes together affect pteropod
shells?
CHECKTEST YOUR THINKINGRate each: FALSE ← 1–2–3–4–5 → TRUE
1. The ocean's pH has stayed the same for millions of years until humans started burning fossil fuels.
F12345T
2. When CO2 dissolves in seawater, it forms carbonic acid (H2CO3) which lowers the pH.
F12345T
3. Ocean acidification only affects animals with shells — fish and other organisms are not harmed.
F12345T
4. A small change in pH (like 0.1) means only a small change in acidity.
F12345T
5. Reducing CO2 emissions would allow ocean pH to recover over time as the ocean releases excess dissolved CO2.
F12345T
Pick any TWO statements — especially any you rated 2, 3, or 4. Justify your rating with evidence:
Statement #___ — I rated it ___ because:
Statement #___ — I rated it ___ because:
[O] SCIENCE CIRCLE
~15 min | End of week+3 pts
[!] My "Aha!" Moment
[?] My Remaining Question
Discussion Protocol: Share ahas, listen actively,
record class discoveries.