Which two gases are primarily responsible for ocean acidification?

Ocean acidification is primarily driven by the absorption of carbon dioxide (CO2) from the atmosphere into the ocean. When CO2 dissolves in seawater, it reacts to form carbonic acid (H2CO3). This process leads to increased concentrations of hydrogen ions, which reduces the pH of the ocean, making it more acidic.

The presence of carbonic acid is crucial because it is the compound that affects the chemical balance of the ocean's water. As the ocean absorbs more CO2, it results in more carbonic acid, which dissociates to release hydrogen ions, further lowering the pH.

Understanding this relationship highlights why carbon dioxide and carbonic acid are the key contributors to ocean acidification, setting them apart from other gases. While oxygen and nitrogen are abundant in the atmosphere, they do not contribute to acidification. Similarly, methane, sulfur dioxide, hydrogen sulfide, and ammonia are not primary contributors to this particular process, as they involve different chemical actions that do not lead to significant decreases in ocean pH.