Navigation Links
'Just right' plant growth may make river deltas resilient

BLOOMINGTON, Ind. -- Research by Indiana University geologists suggests that an intermediate amount of vegetation -- not too little and not too much -- is most effective at stabilizing freshwater river deltas.

The study, "Optimum vegetation height and density for inorganic sedimentation in deltaic marshes," was published online Aug. 24 by Nature Geoscience. The findings may help guide restoration of river deltas, such as those near the mouth of the Mississippi River, which are under threat as sea levels rise.

Authors are William Nardin, a postdoctoral fellow in the Department of Geological Sciences in the IU Bloomington College of Arts and Sciences; and Douglas A. Edmonds, who holds the Robert R. Shrock Professorship in Sedimentary Geology and is an assistant professor of geological sciences.

Vegetation on marsh surfaces in river deltas can slow the flow of water and cause more sediment to be deposited, helping prevent sea-level rise from drowning sensitive marshlands. But the study finds that, if the vegetation is too tall or dense, it diverts water into the river channel, resulting in less sediment being deposited on the marsh.

"In river deltas the effect of vegetation on sedimentation seems to follow the Goldilocks principle," Edmonds said. "You want the amount of vegetation that is just right -- not too much, but also not too little."

The world's river deltas are rich and productive and are home to about 10 percent of the world's population. But they are threatened by an array of forces, including population growth, pollution, development and erosion, as well as sea-level rise associated with climate change.

Edmonds wrote in a 2012 Nature Geoscience article that river deltas can be restored, but it will take a better understanding of the processes involved in their formation and destruction. The current study suggests vegetation could play a role in designing effective river delta restoration.

In tidal saltwater marshes, research has shown that vegetation enhances sedimentation. But scientists know less about how vegetation affects sedimentation in freshwater marshes that are common in river deltas. Nardin and Edmonds used sophisticated computer modeling to study how marsh vegetation influences the transport and deposition of sediment in river deltas. They conducted 75 simulations involving varying scenarios of vegetation height and density and rates of water flow.

They found that vegetation of intermediate height and density results in the greatest deposition of sand and mud. However, if the plants are too tall or densely packed, sediment tends to remain in the river channel, bypassing marshes and being carried directly to the sea.

The researchers also analyzed remote-sensing data collected from Wax Lake Delta in Louisiana. The analysis showed the delta exhibits a hydrodynamic response to the presence of vegetation that corresponds with what the researchers found with their model.

The rate at which sediment is delivered to marshes in river deltas is strongly influenced by storms and flooding, as well as the construction of engineered diversions. The research suggests the resilience of river deltas will depend on the timing of floods and storms relative to the seasonal growth of vegetation. And of course, scientists can't control or even predict when floods will occur.

"That unpredictability adds an interesting twist to the problem," Edmonds said. "The time that the flood wave arrives does not always coincide with the timing of vegetation growth and decay. Those two have to line up just right for vegetation to really enhance deposition of sand and mud."

Contact: Steve Hinnefeld
Indiana University

Related biology news :

1. Not just for the birds: Man-made noise has ripple effects on plants, too
2. Crime and punishment: The neurobiological roots of modern justice
3. Light weights are just as good for building muscle, getting stronger, researchers find
4. Just a few cell clones can make heart muscle
5. Just a question of time?
6. Prenatal whole genome sequencing: Just because we can, should we?
7. One click away: Finding data on Floridas endangered species just got easier
8. Science stars head to Dartmouth for the E.E. Just Symposium
9. Everyone in the pool! Water workouts just as good as on land
10. Recyclable electronics: Just add hot water
11. In-sync brain waves hold memory of objects just seen
Post Your Comments:
Related Image:
'Just right' plant growth may make river deltas resilient
(Date:4/5/2017)... , April 4, 2017 KEY FINDINGS ... to expand at a CAGR of 25.76% during the ... is the primary factor for the growth of the ... MARKET INSIGHTS The global stem ... technology, application, and geography. The stem cell market of ...
(Date:3/30/2017)... NEW YORK , March 30, 2017 ... by type (physiological and behavioral), by technology (fingerprint, AFIS, ... recognition, voice recognition, and others), by end use industry ... travel and immigration, financial and banking, and others), and ... Europe , Asia Pacific ...
(Date:3/24/2017)... Research and Markets has announced the addition of the ... Industry Forecast to 2025" report to their offering. ... The Global Biometric Vehicle Access ... 15.1% over the next decade to reach approximately $1,580 million by ... and forecasts for all the given segments on global as well ...
Breaking Biology News(10 mins):
(Date:10/11/2017)... ... October 11, 2017 , ... At ... Purple announced Dr. Suneel I. Sheikh, the co-founder, CEO and chief research scientist ... has been selected for membership in ARCS Alumni Hall of Fame . ...
(Date:10/11/2017)... ... October 11, 2017 , ... ... today it will be hosting a Webinar titled, “Pathology is going digital. Is ... , on digital pathology adoption best practices and how Proscia improves lab economics ...
(Date:10/11/2017)... ... October 11, 2017 , ... ... and pregnancy rates in frozen and fresh in vitro fertilization (IVF) ... maternal age to IVF success. , After comparing the results from the fresh ...
(Date:10/10/2017)... ... October 10, 2017 , ... For the second time in ... STEM Mentoring Award. Representatives of the FirstHand program travelled to Washington, D.C. Tuesday, ... , US2020’s mission is to change the trajectory of STEM education in America ...
Breaking Biology Technology: