Faces of Rhodes
Dr. Rosanna Cappellato
Assistant Professor of Biology
Noted author Mark Twain helped cement its place in fiction. Its flooded banks this spring brought national news media personalities to stand in its historic waters. Yet despite the Mississippi River’s presence as the western boundary of Memphis, many locals know little about it.
For Rhodes students looking to learn more about the river, a course being taught this fall by Dr. Rosanna Cappellato, assistant professor of Biology, is a good place to start. Eleven students are enrolled in the Mississippi River-themed senior seminar. “Most of them have lived here for at least three years and yet they know very little about the river,” says Cappellato.
Memphis native Blaire O’Neal ’12 agrees. “I never really thought about the river, then I found out Rhodes offered a whole course on it, so I thought that would be a good opportunity to sort of catch up.” O’Neal is studying different forms of pollution that affect the Mississippi such as industrial metals, fertilizers and pesticides.
“I mostly studied Atrazine,” says O’Neal, “which is the most-used pesticide in the United States right now, and it’s considered by many to be a kind of 21st century DDT.” Atrazine is a particularly potent pollutant and, even at very low concentrations, is able to prevent many aquatic species, such as alligators, from reproducing. “It works by changing sex ratios, and we end up with more females than males.”
The course kicked off with a field trip to Memphis’ Mud Island River Park, which contains a scale model of the Lower Mississippi River flowing from the Ohio River to the Gulf of Mexico. “If you want to learn more about the river they have this scale model there and that’s a good place to start,” says Cappellato. The model even features Rhodes as a landmark.
As part of the course’s literature, students read a historical narrative piece by John McPhee titled “The Control of Nature.” The author vividly reflects on the struggle by the U.S. Army Corps of Engineers (USACE) to keep the Mississippi River from changing course. Near the Gulf of Mexico and the Mississippi River Delta, a series of river locks named “Old River Controls” is keeping the Mississippi on its path through Baton Rouge and New Orleans. Cappellato notes that without these controls, the river would gradually shift until most of the water bypassed these cities to travel down what is now the Atchafalaya River to the west.
Flooding is also a concern along the Mississippi, particularly considering the near-record high water level earlier this year, and all the farmland still underwater today. To prevent flooding and to make the river more useful for transport, USACE has installed dams, levees, dikes and canals.
On the one hand, controls have increased the usefulness of the river for transportation – the gradient of the upper Mississippi would make transportation up and down the river very difficult without river locks to raise and lower vessels as they travel.
However, the levees not only prevent rich sediments from depositing in the floodplain and increase the river velocity, but for these reasons may also contribute to a significant loss of wetlands in Louisiana. It has been estimated that land area has decreased about 25 percent since 1932. The loss of wetland has “in recent years demonstrated a growing vulnerability of the Louisiana coast to hurricanes. In fact, the impact of [hurricane] Katrina on the gulf coast was much more severe because of the degradation of this ecosystem,” explains Cappellato.