Question

Which of the following options can be linked to rise in CO\(_2\) concentration in the atmosphere?

• A. Rise in seawater pH and sea surface temperature
• B. Decrease in seawater pH and increase in bicarbonate ion concentration in seawater
• C. Warming of surface ocean water and decrease in carbonate ion concentration in seawater
• D. Decrease in seawater pH and decrease in bicarbonate ion concentration in seawater

Hint:

As atmospheric CO\(_2\) increases, the oceans absorb more CO\(_2\), leading to ocean acidification, a decrease in pH, and an increase in bicarbonate ions. This also results in reduced availability of carbonate ions, which affects marine life.

Answer 1

The Correct Option is B, C

Understanding the Effects of CO₂ on Seawater
As CO₂ concentration in the atmosphere rises, more CO₂ is absorbed by the oceans. This leads to the formation of carbonic acid, which dissociates into bicarbonate ions (HCO₃^-) and hydrogen ions (H⁺). The increased concentration of hydrogen ions causes the seawater pH to decrease (acidification).

Option (B): This is correct because the rise in CO₂ leads to a decrease in seawater pH due to increased acidity, and the concentration of bicarbonate ions increases as a result of CO₂ dissolving into the seawater.

Option (C): This is correct because the rise in CO₂ leads to warming of surface ocean water, which can further exacerbate ocean acidification. The increased CO₂ reduces the concentration of carbonate ions, which are essential for marine organisms to form calcium carbonate shells.

Option (A): This is incorrect because seawater pH actually decreases, not increases, with the rise in CO₂.

Option (D): This is incorrect because while seawater pH decreases, the concentration of bicarbonate ions actually increases, not decreases, with the absorption of CO₂ by the oceans.