Featured Research

from universities, journals, and other organizations

Marshes Dying for Lack of Fresh Water at Maurepas Swamp, Louisiana, US

Date:
March 6, 2010
Source:
Southeastern Louisiana University
Summary:
Without a diversion from the Mississippi River or the introduction of other sources of fresh water in the near future, the Maurepas Swamp in southeast Louisiana will continue on a clear path toward becoming marsh and open water, a new study confirms.

Gary P. Shaffer, Southeastern professor of biological sciences, notes that the Maurepas Swamp complex, the second largest coastal forest in Louisiana, has been radically reduced over the years due to excessive logging, development, changing water levels, nutrient deprivation and saltwater intrusion.
Credit: Image courtesy of Southeastern Louisiana University

Without a diversion from the Mississippi River or the introduction of other sources of fresh water in the near future, the Maurepas Swamp in southeast Louisiana will continue on a clear path toward becoming marsh and open water, a new study by Southeastern Louisiana University biologists and other scientists confirms.

Writing in the Journal of Coastal Research, Gary P. Shaffer, Southeastern professor of biological sciences, notes that the Maurepas Swamp complex, the second largest coastal forest in Louisiana, has been radically reduced over the years due to excessive logging, development, changing water levels, nutrient deprivation and saltwater intrusion. The paper was co-authored with several other scientists from Southeastern and LSU.

"Much of the remaining swamp is in a severe state of deterioration," Shaffer said.

He explained that the establishment of levees over the last century along the Mississippi River to eliminate natural flooding removed a once reliable source of fresh water, sediments and nutrients that swamps require for healthy growth.

"This has enabled salt water from the Gulf of Mexico to make further inland intrusions," he said. "Combined with rising sea levels and the construction of massive canals, such as the Mississippi River Gulf Outlet (MRGO), the intensity and frequency of saltwater intrusions has only grown worse. Consequently, most of the Maurepas Swamp appears to be in transition to marsh and open water."

The scientists' findings are based on comparisons of selected groupings of sites in the southern wetlands of Lake Maurepas. The sites had three different levels of water quality: including stagnant and nearly permanently flooded areas, sites with severe saltwater intrusion, and sites that receive some freshwater runoff. Salinity levels appeared to be the major factor causing sites to rapidly deteriorate, with the most degraded areas located near Lake Pontchartrain or along the margin of Lake Maurepas.

"The Maurepas Swamp is in a steady state of rapid decline, and that's evident by the loss of much of the baldcypress and water tupelo forests that were a mainstay of the swamp," Shaffer said. "Over the past seven years, nearly 20 percent of the original 1,860 trees in our study plots have died."

A Mississippi River diversion -- under study for several years now by the Environmental Protection Agency and scientists at Southeastern and LSU -- would decrease the salinity, increase the levels of nutrients, and provide much needed sediment necessary to rebuild the subsiding swamp, Shaffer explained.

"It is likely that the influences of freshening would be felt in wetlands as distant as Lake Pontchartrain," he said. "Even the smallest proposed diversion would replace all of the water in Lake Maurepas twice each year and it can only exit to Lake Pontchartrain through Pass Manchac and North Pass."

Mississippi River reintroductions have been considered at Violet, Bonnet Carre, La Branch and two in the Maurepas Swamp, Shaffer said

The study also evaluated the region following the 2005 hurricanes, with the scientists concluding that the extensive lateral root systems of baldcypress and water tupelo can hold an entire ecosystem together, while also serving as valuable natural storm buffers.

"If we want to reverse the decline of coastal Louisiana swamps, we have to find and use sources of fresh water that currently are being wasted, including water from the Mississippi River, as well as treated sewage effluent," he said. "The proper freshening of the region should enable restoration of the swamps in the Lake Pontchartrain Basin."

Co-authors of the study included Thais E. Perkins, William B. Wood and Jason Zoller of Southeastern; Susan S. Hoeppner of the LSU Department of Oceanography and Coastal Science; and Demetra Kandalepas of the LSU Department of Biological Sciences. Shaffer also credited the efforts of numerous undergraduate and graduate students who performed much of the field work.


Story Source:

The above story is based on materials provided by Southeastern Louisiana University. Note: Materials may be edited for content and length.


Cite This Page:

Southeastern Louisiana University. "Marshes Dying for Lack of Fresh Water at Maurepas Swamp, Louisiana, US." ScienceDaily. ScienceDaily, 6 March 2010. <www.sciencedaily.com/releases/2010/03/100306152418.htm>.
Southeastern Louisiana University. (2010, March 6). Marshes Dying for Lack of Fresh Water at Maurepas Swamp, Louisiana, US. ScienceDaily. Retrieved July 23, 2014 from www.sciencedaily.com/releases/2010/03/100306152418.htm
Southeastern Louisiana University. "Marshes Dying for Lack of Fresh Water at Maurepas Swamp, Louisiana, US." ScienceDaily. www.sciencedaily.com/releases/2010/03/100306152418.htm (accessed July 23, 2014).

Share This




More Earth & Climate News

Wednesday, July 23, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

New Orleans Plans to Recycle Cigarette Butts

New Orleans Plans to Recycle Cigarette Butts

AP (July 21, 2014) New Orleans is the first U.S. city to participate in a large-scale recycling effort for cigarette butts. The city is rolling out dozens of containers for smokers to use when they discard their butts. (July 21) Video provided by AP
Powered by NewsLook.com
Shark Sightings a Big Catch for Cape Tourism

Shark Sightings a Big Catch for Cape Tourism

AP (July 21, 2014) A rise in shark sightings along the shores of Chatham, Massachusetts is driving a surge of eager vacationers to the beach town looking to catch a glimpse of a great white. (July 21) Video provided by AP
Powered by NewsLook.com
Spectacular Lightning Storm Hits London

Spectacular Lightning Storm Hits London

AFP (July 19, 2014) A spectaCular lightning storm struck the UK overnight Friday. Images of lightning strikes over the Shard and Tower Bridge in central London. Duration: 00:23 Video provided by AFP
Powered by NewsLook.com
A Centuries' Old British Tradition Is Far from a Swan Song

A Centuries' Old British Tradition Is Far from a Swan Song

AFP (July 19, 2014) As if it weren't enough that the Queen is the Sovereign of the UK and 15 other Commonwealth realms, she is also the owner of all Britain's unmarked swans. Duration: 02:18 Video provided by AFP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins