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.
Rene Abadie | Newswise Science News
Rutgers-led innovation could spur faster, cheaper, nano-based manufacturing
14.02.2018 | Rutgers University
New study from the University of Halle: How climate change alters plant growth
12.01.2018 | Martin-Luther-Universität Halle-Wittenberg
A newly developed laser technology has enabled physicists in the Laboratory for Attosecond Physics (jointly run by LMU Munich and the Max Planck Institute of Quantum Optics) to generate attosecond bursts of high-energy photons of unprecedented intensity. This has made it possible to observe the interaction of multiple photons in a single such pulse with electrons in the inner orbital shell of an atom.
In order to observe the ultrafast electron motion in the inner shells of atoms with short light pulses, the pulses must not only be ultrashort, but very...
A group of researchers led by Andrea Cavalleri at the Max Planck Institute for Structure and Dynamics of Matter (MPSD) in Hamburg has demonstrated a new method enabling precise measurements of the interatomic forces that hold crystalline solids together. The paper Probing the Interatomic Potential of Solids by Strong-Field Nonlinear Phononics, published online in Nature, explains how a terahertz-frequency laser pulse can drive very large deformations of the crystal.
By measuring the highly unusual atomic trajectories under extreme electromagnetic transients, the MPSD group could reconstruct how rigid the atomic bonds are...
Quantum computers may one day solve algorithmic problems which even the biggest supercomputers today can’t manage. But how do you test a quantum computer to...
For the first time, a team of researchers at the Max-Planck Institute (MPI) for Polymer Research in Mainz, Germany, has succeeded in making an integrated circuit (IC) from just a monolayer of a semiconducting polymer via a bottom-up, self-assembly approach.
In the self-assembly process, the semiconducting polymer arranges itself into an ordered monolayer in a transistor. The transistors are binary switches used...
Breakthrough provides a new concept of the design of molecular motors, sensors and electricity generators at nanoscale
Researchers from the Institute of Organic Chemistry and Biochemistry of the CAS (IOCB Prague), Institute of Physics of the CAS (IP CAS) and Palacký University...
15.02.2018 | Event News
13.02.2018 | Event News
12.02.2018 | Event News
23.02.2018 | Physics and Astronomy
23.02.2018 | Health and Medicine
23.02.2018 | Physics and Astronomy