“As beaver populations rebound across North America, the ponds they create are proving to be an important factor in removing rapidly growing levels of nitrogen from waterways and estuaries, according to a new study. By creating ponds that slow down the movement of water, the beavers enable nitrogen — which comes from agricultural runoff, septic systems, and other human sources — to seep into soil, where much of it is broken down by bacteria.

“[R]esearchers at the University of Rhode Island said that beaver ponds can remove up to 45 percent of nitrogen in the water. One scientist said that when researchers began to consider the widespread presence of beaver ponds, “we realized that the ponds can make a notable difference in the amount of nitrate that flows from our streams to our estuaries.” Nitrogen pollution is a major problem worldwide, causing toxic algal blooms in rivers, estuaries, and oceans.”

Quoted from the Yale Environment 360 original, here.