APR 04, 2018 9:14 AM PDT

Is the Mississippi slipping out from under us?

A new study published in Marine Geology poses the question: is the Mississippi slipping out from under us? The study, which comes from San Diego State University scientist Jillian Maloney and her colleagues, suggests that the seafloor under the Mississippi River Delta running to the Gulf of Mexico may be under threat of erosion. This erosion was otherwise previously undocumented because it is not as visible as eroding superficial lands. Now, though, the scientists have provided a wide-ranging map that shows just how much unseen erosion has taken place under this great river on its journey to the sea.

"Imagine this as an underwater extension of land loss that we see at the surface. This is a big deal because it can affect so many processes that occur from the coast to the open ocean including marine organisms' lifecycles and underwater landslides," said lead author Maloney.

Indeed, the team explains, land loss has huge impacts on entire ecosystems because the physical and geological changes impact biological life. When sediments build up in a riverbed to form wetlands, for example, whole new worlds are created for species to inhabit. But when those wetlands are eroded because the sediments are literally swept out from under the earth, not only does that habitat disappear with all the life that depended on it, but hurricanes and tidal floods hit harder without that physical barrier, pollution is absorbed into the waterway instead of filtered and broken down, and even human-made infrastructure is affected.

The authors note that this effect is happening with the Mississippi River Delta in large part because of all the dams that block the flow of sediments. In addition, levees that are used for the intent of flood protection also contribute to land loss. Because both dams and levees essentially break up the river, sediment flow is halted - previous studies have estimated that roughly 210 million tons of sediment are impeded from their natural flow.

An aerial view of the Mississippi River Delta. Photo: mississippiriverdelta.org

In order generate their map, Maloney’s team analyzed data from various sources, including old nautical charts, previous NOAA maps, and the oil and gas industry, among others. "From this comprehensive study, we've determined that the Mississippi River Delta has entered a stage of decline. The outlets of the Mississippi River also known as the Bird's Foot Delta have been prograding, or spreading, naturally for hundreds of years, but that has now stopped. The underwater portions of the delta are now retreating like the land loss occurring in our landscape," said study co-author Sam Bentley.

The scientists doubt that the Mississippi River Delta is the only large river system experiencing this extensive erosion due to loss of sediment flow. "Given the similarities between the Mississippi River Delta and river systems worldwide, we expect other major delta systems are entering decline. This has implications for delta ecosystems and biological, geological and chemical processes worldwide," Bentley said. The Mekong River Delta, the world’s third largest delta, is also facing erosion due to human activities, and scientists are rightfully concerned over what may be the future of these important ecosystems that support so much life.

Sources: Science Daily, Marine Geology, Nature

About the Author
  • Kathryn is a curious world-traveller interested in the intersection between nature, culture, history, and people. She has worked for environmental education non-profits and is a Spanish/English interpreter.
You May Also Like
JAN 05, 2021
Microbiology
Finding ways to Culture Bacteria From Extreme Environments
JAN 05, 2021
Finding ways to Culture Bacteria From Extreme Environments
In order to study bacteria, it has to be grown in the lab. That’s no problem for many common strains of bacteria t ...
JAN 18, 2021
Earth & The Environment
Another record we didn't want: 2020 was the hottest year yet
JAN 18, 2021
Another record we didn't want: 2020 was the hottest year yet
It will likely come as no surprise that 2020 held another record that we wish it didn’t: hottest year on record. W ...
JAN 30, 2021
Earth & The Environment
Invasive species reduce water resources in Ethiopia
JAN 30, 2021
Invasive species reduce water resources in Ethiopia
An invasive evergreen tree, known as Prosopis juliflora, is quite the thirsty species. Prosopis has taken over large swa ...
MAR 02, 2021
Earth & The Environment
Why apocalyptic discourse doesn't work when talking about climate change
MAR 02, 2021
Why apocalyptic discourse doesn't work when talking about climate change
NASA has predicted 15 inches of sea level rise by 2100. By that same year, the IPCC predicts atmospheric CO2 concentrati ...
APR 25, 2021
Microbiology
Plant-Eating Microbes Expand the Tree of Life
APR 25, 2021
Plant-Eating Microbes Expand the Tree of Life
After microbes called archaea were discovered in the 1970s, a branch was added to the tree of life after some debate, wh ...
MAY 01, 2021
Space & Astronomy
Satellite Images Show Accelerating Retreat of World's Glaciers
MAY 01, 2021
Satellite Images Show Accelerating Retreat of World's Glaciers
In a new study, an international team of researchers have found that almost all of the world’s glaciers are in ret ...
Loading Comments...