The Mississippi River has been dramatically changed by agricultural practices, says new research in the journal Nature. In the past 50 years or so, carbon levels in the river have jumped 40 percent, while the actual amount of water flowing through the riverbed has increased 9 percent — the equivalent of five Connecticut Rivers. “Agricultural practices are causing a greater percentage of rainfall to make it to river water instead of being evaporated back into the atmosphere,” explains researcher Peter Raymond. The extra-mighty Mississippi then transports ever more nutrients and pollution into the Gulf of Mexico, where they contribute to an oxygen-starved dead zone. But hey, at least we’ve got lots of corn!

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