Asidifikasyon

Asidifikasyon is the process by which a system becomes more acidic, reflected by a lower pH and a higher concentration of hydrogen ions. It can occur when acids are added, basic substances are removed, or when carbon dioxide dissolves in water to form carbonic acid.

In aquatic systems, a major form is ocean acidification, driven by the uptake of atmospheric CO2. The reaction CO2 + H2O ⇌ H2CO3 ⇌ H+ + HCO3− shifts toward more H+, reducing carbonate ion (CO3^2−) availability that many marine organisms rely on to build calcium carbonate shells and skeletons. The result is slower calcification and altered biogeochemical cycles.

In soils and freshwaters, acidification can arise from acid rain, emissions of sulfur and nitrogen oxides, and the use of acidifying fertilizers. Lower pH changes nutrient availability and can increase solubility of toxic metals such as aluminum, affecting plant growth and aquatic life. Buffering capacity, natural buffering minerals, and soil type determine the extent of acidification and recovery potential. Mitigation includes reducing emissions of acidifying gases, applying lime or other bases to raise pH, and practices that maintain buffering capacity.

Measurement and monitoring rely on pH as the primary indicator, along with indicators of acidity such as titratable acidity and alkalinity, and in water bodies, parameters of the carbonate system, including dissolved inorganic carbon and partial pressure of CO2. Understanding asidifikasyon is essential for managing ecosystems, agriculture, and climate-related impacts.