Freshwater acidification

Freshwater acidification occurs when acidic inputs enter a body of fresh water through the weathering of rocks, invasion of acidifying gas (e.g. carbon dioxide), or by the reduction of acid anions, like sulfate and nitrate within a lake. Freshwater acidification is primarily caused by sulfur oxides (SO_x) and nitrogen oxides (NO_x) entering the water from atmospheric depositions and soil leaching_. Carbonic acid and dissolved carbon dioxide can also enter freshwaters, in a similar manner associated with runoff, through carbon dioxide-rich soils. Runoff that contains these compounds may incorporate acidifying hydrogen ions and inorganic aluminum, which can be toxic to marine organisms. Acid rain is also a contributor to freshwater acidification. It is created when SO_x and NO_x react with water, oxygen, and other oxidants within the clouds.