How can nitrogen deposition from air pollution cause eutrophication in lakes and coastal waters?

Nitrogen deposition from air pollution contributes to eutrophication by introducing excess nutrients into aquatic ecosystems, which disrupts the natural balance of these environments.12

When nitrogen oxides ($N{O}_x$) are emitted into the atmosphere—primarily through the burning of fossil fuels—they can be deposited into lakes, estuaries, and coastal marine systems through both wet and dry deposition. This atmospheric input acts as a form of nutrient loading, similar to agricultural or sewage runoff.12

The process leads to eutrophication through the following steps:
* Over-enrichment: The influx of nitrogen promotes the rapid, excessive growth of algae and other aquatic plants.12
* Oxygen Depletion: As these organisms die, they are decomposed by microbes, a process that consumes large amounts of dissolved oxygen.12
* Hypoxia: This leads to hypoxia, or extremely low oxygen levels, which can create "dead zones" where most aquatic life, such as fish and mollusks, cannot survive.32

Addressing this form of pollution is an ethical imperative, as it protects the health of global water resources and the diverse life forms that depend on them.2