Louisiana's wetlands face post-Katrina trouble
Atchafalaya Delta in Louisiana as seen by Landsat satellite
DB: This is Earth and Sky. In the aftermath of Hurricane Katrina, wetland areas of the Mississippi Delta are struggling.
JB: Louisiana’s wetlands – vast cypress swamps and marshes – form a natural buffer from storms. But the weight and compression of thousands of years of sediment dumped into the delta are causing wetlands to sink slowly.
DB: Scientists call this subsidence. We spoke with Mead Allison, a coastal geologist at Tulane University in New Orleans.
Mead Allison: … The elevation of these salt marshes, in particular, is only a matter of inches to a couple of feet above sea level. So, as you can imagine, if you have subsidence rates that are approaching an inch per year, it doesn’t take very long before these wetlands are literally drowned. And, the other mechanism that’s working naturally on top of that is wave attack, where the edges of the marshes are being nibbled away at by wave attack during storms, particularly during hurricanes like Katrina.
JB: Allison said post-Katrina surveys indicate that as much as 40% of marshland in some of most seriously effected areas was devastated by the hurricane. But, he added, scientists will have a better idea of the degree of wetland loss around April or May, when plant life in the marshes starts to grow again. We’ll have more about coastal restoration in Louisiana on a future show. Thanks today to NOAA, the National Oceanic and Atmospheric Administration. We’re Block and Byrd for Earth and Sky.
Our thanks to:
Mead Allison
Associate Professor
Department of Earth and Environmental Sciences
Tulane University
New Orleans
Additional Teacher Resources
Teachers Domain: Hurricane Katrina: Wetland Destruction
Humans have been altering the natural environment to suit their needs for thousands of years. We have constructed shelter where none existed, planted food crops where forests once flourished, and in one of the more striking examples, built an entire city in the middle of a swamp. New Orleans, Louisiana, is a testament to the human will and ingenuity required to overcome seemingly impossible odds – in a part of the world where a great deal of commerce stood to be gained. However, in August 2005, Hurricane Katrina tragically illustrated the potential consequences of defying the forces of nature.
U.S. Geological Survey: National Wetlands Research Center: Hurricanes Katrina and Rita
Studying hurricanes – from tracking the recovery process across decades past to predicting their future impact on habitats – is critical to the USGS National Wetlands Research Center research mission. Although headquartered in Lafayette, Louisiana, NWRCs hurricane researchers find themselves at work throughout the world. Presented here are some examples of NWRCs wide-ranging hurricane research efforts.
