What environmental change can significantly affect marine life due to increased CO2 levels?

Ocean acidification is the correct answer as it directly results from increased levels of carbon dioxide (CO2) in the atmosphere. When CO2 is absorbed by seawater, it reacts with water to form carbonic acid, which subsequently dissociates into bicarbonate and hydrogen ions. This process leads to a decrease in the pH of the ocean, making it more acidic.

The impact of ocean acidification on marine life is profound, particularly for organisms that rely on calcium carbonate to form their shells and skeletons, such as corals, mollusks, and some plankton species. The increased acidity reduces the availability of carbonate ions, which these organisms need to build and maintain their structures. This can lead to weaker shells and skeletons, making these organisms more vulnerable to predation and environmental stressors.

Additionally, ocean acidification can disrupt the sensory systems of fish and other marine animals, affecting their behavior and predation dynamics. As a result, entire marine ecosystems can be altered due to the cascading effects of reduced species populations and biodiversity.

While ocean warming, pollution, and overfishing also have significant effects on marine environments, they are not primarily driven by increased CO2 levels in the same direct manner as ocean acidification is. Each of