What is the primary environmental impact of excess nitrogen in water bodies?

The primary environmental impact of excess nitrogen in water bodies is that it encourages the proliferation of harmful algal blooms. When nitrogen is available in large quantities due to runoff from agricultural practices, wastewater discharge, or other sources, it can lead to rapid growth of algae. This phenomenon, known as eutrophication, can create dense algal blooms that not only cover the surface of the water but also can produce toxins harmful to aquatic life and human health.

These blooms can deplete oxygen in the water when they die off and decay, leading to hypoxic or anoxic conditions that can kill fish and other aquatic organisms. The negative effects on water quality can extend to various aspects of the ecosystem, diminishing the overall health and balance of aquatic environments. Hence, the understanding of nitrogen’s role in promoting harmful algal blooms is crucial for effective aquatic weed management and protecting water body health.