Satellites Spot Mighty Mississippi – In The Atlantic

September 15, 2005
Satellites Spot Mighty Mississippi – In The Atlantic 1

Scientists using satellite imagery found that at least 23 percent of the water released from the mouth of the Mississippi River from July through September 2004 traveled quite a distance - into the Gulf of Mexico, around the Florida Keys, and into the Atlantic Ocean.

Image: Phytoplankton appear as brilliant streaks of blue and green over the South Atlantic Ocean in this image from the Moderate-resolution Imaging Spectroradiometer (MODIS) aboard NASA’s Terra satellite on January 4, 2005. Credit: NASA GSFC

The researchers combined data from the Moderate Resolution Imaging Spectroradiometer (MODIS) aboard NASA's Terra and Aqua satellites with information collected from ships to study the water discharge, appearing as a dark plume that stretched from the Mississippi Delta, around Florida and up to the Georgia coast. MODIS detects the color of the ocean due to changes in the amount of tiny ocean plants floating on the ocean's surface known as phytoplankton, or algae and other decaying materials.

"This is the first time we have been able to estimate the amount or volume of freshwater discharged and carried over such remote distances. By combining the very detailed data from MODIS with observations from ships, we got a three-dimensional view of the Mississippi plume," said Chuanmin Hu, of the College of Marine Science, University of South Florida, St. Petersburg, Fla., and lead author of the study. By using MODIS data with information on sea surface currents and sea salt levels (salinity), the scientists estimated that about 20 billion tons of Mississippi River water reached the Florida Straits and Gulf Stream off the Georgia coast. This is about four times the volume of Lake Okeechobee, the largest lake in Florida.

Satellites Spot Mighty Mississippi – In The Atlantic

Image right: This image from MODIS aboard NASA’s Terra satellite shows the murky brown water of the Mississippi River mixing with the dark blue water of the Gulf of Mexico two days after a rainstorm. Credit: NASA NASA/University of Wisconsin-Madison

The research also shows that such plumes created by the Mississippi River can travel over large distances, more than 1240 miles (2000 kilometers).

Beyond studying the causes of such events, researchers are using satellite information with observations from ships and "ocean surface drifters" - instruments resembling balloons that travel the ocean surface, to get a better idea of how these plumes affect marine life.

"Mississippi River water may have some impact on marine life in remote delicate ecosystems like the Florida Keys. But we are still not clear about the potential impacts of pollutants and pesticides," said Hu. "Not all effects will be bad; in fact, some light dark water events might actually protect bottom ocean dwellers, like coral, by providing them with shade."

The study is published in the July 2005 issue of Geophysical Research Letters under support of NASA, NOAA, and ONR as a contribution to the SouthEast Atlantic Coastal Ocean Observing System (SEACOOS). Coauthors include oceanographers James Nelson from the Skidaway Institute of Oceanography, Elizabeth Johns from NOAA’s Atlantic Oceanographic and Meteorological Laboratory, and Zhiqiang Chen, Robert Weisberg, and Frank Muller-Karger from the University of South Florida.

by Mike Bettwy, Goddard Space Flight Center

Explore further: Stinking mats of seaweed piling up on Caribbean beaches

Related Stories

Stinking mats of seaweed piling up on Caribbean beaches

August 10, 2015

The picture-perfect beaches and turquoise waters that people expect on their visits to the Caribbean are increasingly being fouled by mats of decaying seaweed that attract biting sand fleas and smell like rotten eggs.

2015 Gulf of Mexico dead zone 'above average'

August 5, 2015

Scientists have found this year's Gulf of Mexico dead zone—an area of low to no oxygen that can kill fish and marine life—is, at 6,474 square miles, above average in size and larger than forecast by NOAA in June. The ...

Predicting the shape of river deltas

July 22, 2015

The Mississippi River delta is a rich ecosystem of barrier islands, estuaries, and wetlands that's home to a diverse mix of wildlife—as well as more than 2 million people. Over the past few decades, the shape of the delta ...

Recommended for you

Long-sought chiral anomaly detected in crystalline material

September 3, 2015

A study by Princeton researchers presents evidence for a long-sought phenomenon—first theorized in the 1960s and predicted to be found in crystals in 1983—called the "chiral anomaly" in a metallic compound of sodium and ...

Making nanowires from protein and DNA

September 3, 2015

The ability to custom design biological materials such as protein and DNA opens up technological possibilities that were unimaginable just a few decades ago. For example, synthetic structures made of DNA could one day be ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.