Read/listen to the full story at Science Friday.
In the Gulf of Mexico is an ecological dead zone, caused by algal blooms at the mouth of the Mississippi River. Warmer ocean temperatures provide the perfect conditions for algae to grow out of control, suffocating seagrass beds and killing fish, dolphins, and manatees. Fueling this toxic algae’s growth is nitrogen. The Mississippi River empties into the gulf, and drainage water from farms along it carries fertilizer ingredients—straight into the marine ecosystem.
While farmers have tried using practices to reduce fertilizer runoff, like cover crops, no-till farming and conservation buffers, for decades, the problem has only gotten worse. According to a new paper published in the journal Transactions of the American Society of Agricultural and Biological Engineers, a creative new approach involves denitrifying bioreactors—a system that allows bacteria to help convert nitrate in the water to harmless dinitrogen gas.
“It’s a complicated name, but it’s really a very simple idea,” says Laura Christianson, assistant professor of crop sciences at the University of Illinois at Urbana Champaign, and lead author on the study. She talks with SciFri producer Katie Feather about how a simple system involving woodchips in a trench can help keep nitrogen out of drainage water from farms across the midwest. Katie also speaks to Shirley Johnson, a farm-owner from Peoria, Illinois, about why she adopted the bioreactor technology, and what farmers can do to help their downstream neighbors.