Nutrient Loading: Too Much of a Good Thing

October 12, 2015

CBL Professor Dr. Walter Boynton is directing an expansive study on the movement and impact of nutrients in the Chesapeake Bay and tributary rivers.

Excessive nutrient loading occurs when large amounts of nitrogen and phosphorus from the land and atmosphere enter tidal waters — often as a result of human activities such as farming, wastewater treatment plant discharges, and stormwater run-off.  A certain amount of nutrients is necessary to support aquatic life, but “too much of a good thing,” as Boynton says, is harmful to water quality, habitats, and general ecosystem health.  Nutrients encourage the growth of harmful algae that block the sunlight that underwater grasses need to grow and use up the oxygen in the water that most organisms need to survive.

Since the 1980s, researchers have measured the Bay’s climate, river flows, and other water quality variables.  Boynton’s team will pull together information like this, from decades of research, and use computer modeling to learn more about how nutrient loading affects the Bay ecosystem. 

The project will determine how different weather conditions have affected the impact of nutrient loading on the Bay through the years — for instance, whether the Bay suffers more from nutrient loading in years with heavy rainfall or years with droughts.  They will also examine how nutrient enrichment affects food webs.

“We are trying to pull all the processes together and see what it tells us,” said Boynton, who hopes this project will help determine the healthiest level of nutrients for the Bay.  Boynton’s work will inform policies and has applications for the worldwide problem of nutrient loading in coastal ecosystems.