Humans tend to make messes, and when it comes to the excess nitrogen we contribute to waterways, aquatic plants get stuck cleaning up. Nutrients such as nitrogen in wastewater and agricultural runoff often escape into rivers, where they can overstimulate the growth of plankton, resulting in excessive algal blooms and oxygen-depleted conditions as they decompose. Submerged riverine plants can partially mitigate this effect by taking up nitrogen-containing compounds from the water.
