Question

1. what is the primary component of seawater by volume?

a) dissolved gases
b) organic matter
c) water
d) nutrients

1. which ions make up approximately 85% of the dissolved salts in seawater?

a) calcium and potassium
b) carbonate and bicarbonate
c) magnesium and sulfate
d) sodium and chloride

1. what is ocean acidification primarily caused by?

a) overfishing
b) increased levels of atmospheric carbon dioxide
c) rising sea temperatures
d) heavy metal pollution

1. which marine organisms are particularly vulnerable to ocean acidification?

a) fish
b) marine mammals
c) sea turtles
d) shellfish

1. what happens to carbonate ion availability as seawater becomes more acidic?

a) it decreases
b) it remains the same
c) it increases
d) it fluctuates

Explanation:

1. Seawater is mainly water. Dissolved gases, organic matter and nutrients are in much smaller amounts.
2. Sodium and chloride ions make up about 85% of the dissolved salts in seawater, forming sodium - chloride which is common salt.
3. Ocean acidification is mainly caused by increased atmospheric carbon dioxide as it dissolves in seawater and forms carbonic acid.
4. Shellfish are vulnerable to ocean acidification because they need carbonate ions to build their shells, and acidification reduces carbonate ion availability.
5. As seawater becomes more acidic, the carbonate ion availability decreases due to chemical reactions that convert carbonate ions to bicarbonate ions.

Answer:

1. c) Water
2. d) Sodium and chloride
3. b) Increased levels of atmospheric carbon dioxide
4. d) Shellfish
5. a) It decreases