How does acid rain affect lakes and streams?

Acid rain significantly degrades the health of lakes and streams, particularly in regions with low buffering capacity where the environment cannot neutralize incoming acidity.12

The primary impacts include:

• Loss of Biodiversity: Increased acidity directly harms aquatic organisms such as fish, crayfish, and clams, leading to a sharp decline in species diversity.1
• Aluminum Toxicity: Acidification mobilizes aluminum from surrounding soils into the water. In its dissolved form, this metal is toxic to aquatic life and can damage fish gills, impairing their ability to breathe.12
• Bioaccumulation of Toxins: High acidity accelerates the conversion of mercury into methyl mercury, a potent neurological toxin. This substance accumulates in the food chain, reaching dangerous levels in top predators and often necessitating government health advisories regarding fish consumption.1
• Episodic Acidification: During snowmelt, accumulated acids can be released in a concentrated "pulse" of acidic water, which can be lethal to sensitive organisms.1