The Mississippi River is more than just a river, more than just a way to move goods from one port to another. The river is a living, breathing thing.

Flowing from Lake Itasca in Minnesota through the Midwest and ending its destination at the Gulf of Mexico, one of North America’s most beautiful and powerful resources — the Mississippi River — runs right beside our beloved city.

Numerous events from Fourth of July fireworks, the BluzCruz Canoe and Kayak race, and endurance races like Over the River Run and Bricks and Spokes are held throughout the year just to highlight the aesthetics of the river.

Those events only touch the surface of nature’s masterpiece and a whole new world lies underwater.

As you travel farther south down the river from its origin, the structure changes, impacting the species living in the area.

The upper part of the river is impounded by a series of pools and dams, beginning at St. Louis, while the lower part is freer flowing.

About 100 different species of marine life are found only in the lower region of the Mississippi River.

If the upper portion and the tributaries flowing into the river were included it would be about 250 species, said Dr. Jack Killgore, a research fishery biologist at the U.S. Army Corps of Engineers Engineering Research and Development Center.

Killgore compared the number of species found in the Mississippi to the 500 different types found in the Amazon, which he said is the largest and most diverse system in the world.

“You have different species that inhabit different parts of the river,” said Dr. Jan Hoover, a zoologist studying fish in the coastal and hydraulic laboratory at ERDC.

It’s also the epicenter of archaic fish diversity.

“To me, the most interesting part about (the river) is that it harbors interesting populations of archaic fish. I don’t know about any other place in the world where you have these prehistoric-type fish, who in most cases are thriving,” Hoover said.

The paddlefish is one of the primitive species living in the river. The freshwater eel, which spawns in the Sargossa Sea in the Atlantic Ocean, makes its way up the Gulf of Mexico into the Mississippi River. However, only the female eels swim upstream.

Movements and reproduction of fish are tied into the rise of the river and three factors can affect reproduction.

Other than the actual rise of the Mississippi, changes in daylight and water temperature influence how and where a fish can spawn.

“Change in daylight, which tells them the days are getting warmer and longer,” Hoover said. “Fish don’t spawn in the same temperature, and as water warms, certain fish tend to move to where their young can roam. Some fish spawn as the river is rising, other fish spawn when the water is already high and others spawn when the water is going down.”

One of the most fascinating species of the lower Mississippi is the pallid sturgeon, which became federally endangered in 1990.

The Endangered Species Act of 1972 required any federal agency to comply with certain standards to ensure the survival of those species.

“A lot of species like pallid sturgeon were listed before a lot of information was known about their life history, ecology or abundance. Once we started looking for the species and actually targeting them in our collections we found out there were many more sturgeon in the river, they were healthy and self-sustaining.”

Sturgeons naturally live at the bottom of the Mississippi River. They have long fins and when encountered with high flows of water, they use their fins to submerge themselves beneath the currents.

Pallid sturgeon found in the lower part of the river look different than those found in the Missouri River. Hoover said some suggest that the lower Mississippi River pallid sturgeons have crossed populated with shovelnose sturgeon, which is contentious.

Habitat destruction, the reduced input in the river, and the change in sediments have been linked to the endangerment of pallid sturgeon.

“Toxins have been implicated, and inter-gender sturgeon have been reported, which is never a good sign for a species,” Hoover said.

Aside from environmental aspects damaging their habitats, sturgeons have been captured and harvested for caviar.

“Caviar is in great demand still, and there’s only a few species that produce the black eggs,” Killgore said. “When the Endangered Species Act kicked in and we started paying attention to these sturgeon, we could start rehabilitating and restoring aquatic habitats to try and increase their numbers even further.”

Currently, work is being done to stop an invasive group of fish from entering the Great Lakes in the upper part of the country. Asian carp – mostly the silver and big head, but also grass and black carp – are the principle invasive fish. They were brought over from Asia to eat algae and phytoplankton.

Scientists thought the carp would solve problems associated with algae, but they escaped into the Mississippi River and began reproducing exponentially.

“They went from a few hundred, to 10,000 to 100,000 to now there’s millions of them in the Mississippi,” Killgore said.

Barriers are being built across the only permanent canal connecting the Great Lakes to the Mississippi to prevent their unwelcomed presence. Scientists fear the presence of Asian carp in the Great Lakes to be catastrophic.

“We’re doing electrical testing on these fish. If those barriers go down then they’re into Lake Michigan, and once you’re into Lake Michigan, you got access to all the Great Lakes,” Kilgore said.

Killgore and Hoover experiment with the smaller carp because it’s a more efficient form of testing. It takes more electricity to stop a smaller carp, and if results show they can stop a small one, then they can also stop larger carps as well.

Although there was a problem with legacy pesticides in the Mississippi River, with all the movement of water and sediments the river has encountered, it has become a clean environment.

“There are no fish advisories in the Mississippi River proper. The fish that you catch there are clean of pesticides and heavy metals,” Killgore said. “In the tributaries now there are problems with legacy pesticides and when you get into the fields it’s still a problem.”