Beavers May be Saving Estuaries from Nitrogen by Building Ponds

Beavers are doing more to help the environment than you might have thought. Scientists have found these furry mammals are helping prevent harmful levels of nitrogen from reaching vulnerable estuaries in the Northeastern United States by creating ponds.

Nitrogen has been increasing in Northeast waters for years. The use of nitrogen fertilizers has risen, and urbanization has brought in influences such as septic systems. This nitrogen is released into small streams and ponds and eventually travels to estuaries, which is where rivers meet the sea.

So what's the big deal? High levels of nitrogen in these areas stimulate algal blooms. As these organisms die and decompose, oxygen is consumed from bottom waters, creating low oxygen levels that can generate fish kills. Most people are aware of dead zones in the Gulf of Mexico, and this same issue is now affecting the estuaries by the coastline of the Northeast United States.

"What motivated us initially to study this process was that we were aware of the fact that beaver ponds were increasing across the Northeast," said Arthur Gold, one of the researchers, in a news release. "We observed in our other studies on nitrogen movement that when a beaver pond was upstream, it would confound our results."

The researchers realized that the ponds created by beavers were creating the ideal conditions for nitrogen removal. In order to see how effective these ponds were, the scientists took sample cores of soil and added nitrogen to them. These samples were large enough to incorporate the factors that generate chemical and biological processes that take place in the much larger pond.

The researchers found that bacteria in the soil transformed nitrogen into nitrate and then into nitrogen gas, removing it from the system. In fact, this process can remove about 5 to 45 percent of the nitrogen in the water.

"I think what was impressive to us was that the rates were so high," said Gold. "They were high enough and beavers and becoming common enough, so that when we started to scale up we realized that the ponds can make a notable difference in the amount of nitrate that flows from our streams to our estuaries."

The findings are published in the Journal of Environmental Quality.

Related Stories

Severe Droughts and Flooding in California May Double by 2100

Beavers' Decay-Resistant Tooth Enamel May Save Humans' Teeth

For more great science stories and general news, please visit our sister site, Headlines and Global News (HNGN).