Featured Research

from universities, journals, and other organizations

Troubled islands: Hurricanes, oil spill and sea level rise

Date:
October 29, 2010
Source:
Geological Society of America
Summary:
The islands flanking the outlet of the Mississippi River are not only facing losses due to sea level rise and local subsidence, according to one study, but new unknown impacts from oil recovery operations, say researchers working on another project. Some islands could disappear entirely in coming decades, exposing huge swaths of marshland to the waves of the open sea.

The islands flanking the outlet of the Mississippi River are not only facing losses due to sea level rise and local subsidence, according to one study, but new unknown impacts from oil recovery operations, say researchers working on another project. Both will be presenting their work on Nov. 1 and 2 at the meeting of the Geological Society of American in Denver. Some islands could disappear entirely in coming decades, exposing huge swaths of marshland to the waves of the open sea.

On one side of the Mississippi River outlet, to the east of the river outlet, is the Chandeleur Islands-Biloxi Marsh system which is on it's last legs, say researchers studying the recent geological history of the area via peat layers beneath in the marshes. On the other side, to the west, is Grand Isle which is the focus of a study that helps document what conditions BP needs to restore oil-damaged beaches to return to some kind of normal state -- at a time when the island itself is undergoing massive and rapid changes due to hurricanes and repeated beach nourishment efforts.

Islands' Last Gasps

The Chandeleur Islands, are remote, tenuous strips of sand that have served as surf breaks for the steadily sinking Biloxi Marsh. The marshes used to be farmland and are still fishing grounds, though no one lives in the area today, say researchers who now say these islands' are on track for oblivion.

"Hurricanes have done a number on them," said Mary Ellison of the University of New Orleans. Ellison and her colleagues have been putting the present storm batterings and bleak future of the islands and marsh into perspective by studying the past via sediments beneath the marsh. Ellison is scheduled to present their work on Nov. 2.

The sediments show that a thousand years ago the disappearing marshes were part of the delta with the Mississippi river debouching in an eastern direction, loading the area with sediments. Then the river abandoned the east channel and drained further west. Waves from the Gulf took over and started chipping away at the delta, eventually winnowing out the finer grained silts and leaving the larger-grained sand. That piled up along long strips to create the Chandeleur Islands.

Today, the thousand-year trend is being accelerated by the lack of any sand from the Mississippi River to feed the islands. The islands are now cannibalizing themselves in order to maintain their shorelines. Unfortunately, unlike what was once supplied by the river, the supply of cannibalized sediment is finite The result is that the islands are on course to become little more than shoals in 50 years or so, Ellison explains.

"These islands are beyond the point of recovery," said Ellison. If the past is any measure of the future, the loss of the islands will allow more waves to attack the marsh directly, which will lead to more winnowing of fines and coarse material, and perhaps the creation of another long strip of islands closer to the mainland, she said.

"It's kind of at warp speed" compared to such changes at other barrier island systems along other coasts, said Ellison. And that's exactly why the Chandeleur Islands are so important to study for the sake of barrier islands everywhere.

Beaches in 3D

Far to the west, on the other side of the current Mississippi River outlet, a section of Grand Isle State Park has been divided into 59 cross sections 50 meters apart along a 3 kilometer stretch of beach in order to study how the beach is changing over time. Researchers from Tulane University and the University of Massachusetts at Dartmouth have been monitoring the beaches evolution since Feb. 2008, which has included the effects of two hurricanes, two beach nourishment projects and BP oil clean-up operations.

"There have been two beach nourishments since Gustav and Ike," said Tyler Brown of Tulane University. Brown is presenting a poster on the ongoing project Nov. 1 at the annual meeting of the Geological Society of America in Denver.

"The BP cleaning process is to scrape the top layer of sand off the beach and clean it," Brown said. With the oil spill coming on top of the most recent beach nourishment project completed in March 2010, that has resulted in some interesting changes and maybe even a net gain of sand for the beaches in some areas, he said.

"I was actually very surprised by the result of our data sets," Brown said. He hopes to have additional data from October measurements to present at the meeting that may help tease out the effect of oil spill clean up operations on the Grand Isle beach sand budget.


Story Source:

The above story is based on materials provided by Geological Society of America. Note: Materials may be edited for content and length.


Cite This Page:

Geological Society of America. "Troubled islands: Hurricanes, oil spill and sea level rise." ScienceDaily. ScienceDaily, 29 October 2010. <www.sciencedaily.com/releases/2010/10/101029132926.htm>.
Geological Society of America. (2010, October 29). Troubled islands: Hurricanes, oil spill and sea level rise. ScienceDaily. Retrieved April 20, 2014 from www.sciencedaily.com/releases/2010/10/101029132926.htm
Geological Society of America. "Troubled islands: Hurricanes, oil spill and sea level rise." ScienceDaily. www.sciencedaily.com/releases/2010/10/101029132926.htm (accessed April 20, 2014).

Share This



More Earth & Climate News

Sunday, April 20, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Drought Concerns May Hurt Lake Tourism

Drought Concerns May Hurt Lake Tourism

AP (Apr. 18, 2014) Operators of recreational businesses on western reservoirs worry that ongoing drought concerns will keep boaters and other visitors from flocking to the popular summer attractions. (April 18) Video provided by AP
Powered by NewsLook.com
Man Claims He Found Loch Ness Monster With... Apple Maps?

Man Claims He Found Loch Ness Monster With... Apple Maps?

Newsy (Apr. 18, 2014) Andy Dixon showed the Daily Mail a screenshot of what he believes to be the mythical beast swimming just below the lake's surface. Video provided by Newsy
Powered by NewsLook.com
First Ever 'Female Penis' Discovered In Animal Kingdom

First Ever 'Female Penis' Discovered In Animal Kingdom

Newsy (Apr. 18, 2014) Not only are these newly discovered bugs' sex organs reversed, but they also mate for up to 70 hours. Video provided by Newsy
Powered by NewsLook.com
Ark. Man Finds 6-Carat Diamond At State Park

Ark. Man Finds 6-Carat Diamond At State Park

Newsy (Apr. 18, 2014) An Arkansas man has found a nearly 6.2-carat diamond, which he dubbed "The Limitless Diamond," at the Crater of Diamonds State Park. Video provided by Newsy
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