Study: Farming Changes Mississippi River

A study by Yale and Louisiana State universities suggests farming has changed the hydrology and chemistry of the Mississippi River.

The research suggests agricultural activities have injected more carbon dioxide into the river, raising river discharge during the past 50 years.

The scientists tracked changes in the discharge of water and the concentration of bicarbonate, which forms when carbon dioxide in soil water dissolves rock minerals.

Bicarbonate in rivers, the scientists said, plays an important, long-term role in absorbing atmospheric carbon dioxide, a greenhouse gas. Oceans then absorb the carbon dioxide, but become more acidic in the process, making it more difficult for organisms to form hard shells — a necessary function in coral reefs, for example.

Researchers concluded that liming and farming practices, such as changes in tile drainage, tillage practices and crop type, are most likely responsible for the majority of the increase in water and carbon in the Mississippi River — North America’s largest river.

Yale Associate Professor Pete Raymond, who led the study, along with LSU Professor R. Eugene Turner and graduate student Whitney Broussard report their findings in the journal Nature.