Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Fingerprinting erosion

03.09.2015

Solving the mystery of erosion in the south Tobacco Creek watershed

You may have noticed that after a heavy rainstorm, creeks and rivers often turn the color of chocolate milk. That cloudy brown color is caused by sediments--weathered rock material ranging in size from tiny granules of mud to stones. As it courses along, water sweeps up sediments in the well-known process of erosion. Eventually, the sediments find a home, sometimes in a place where it isn't wanted. And, it's not just mud and sand that gets carried to water sources. Contaminants often catch a ride to waterways by clinging to sediments.


Soil experts David Lobb and Dr. Sheng Li check sediment collection traps. The sediment is collected annually to track the origin and pattern of soil migration.

Photo credit Landice Yestrau

Soil scientist David Lobb investigates the origin of these nomadic sediments. His work is in the Tobacco Creek Watershed, a collection of streams that flow into the Red River and ultimately dump into Lake Winnipeg, Canada. Lake Winnipeg is the final resting place of three major rivers, making it the second largest watershed in Canada. It feels the effects of activity taking place upstream.

"We are all being challenged to look at the watershed as a whole, not just at the water that flows out a watershed," says Lobb.

Watershed health and water quality issues are a growing concern. A variety of human activities can negatively impact watersheds.

Fertilizers used to bolster crop yields, sewage pollution from treatment facilities, and refuse from livestock can leach an excess of nutrients. The nutrients, especially phosphorus, enter large bodies of water like Lake Winnipeg. Algae feeds on this influx of phosphorus and goes into a frenzy of growth, which can lead to the choking out other species and throwing off the function of the entire ecosystem. Sediments are often blamed for carrying this nutrient runoff from topsoil sources like farm fields and livestock production areas.

In the context of these issues, Lobb and his team were keen to examine the sediments traveling downstream toward Lake Winnipeg. In order to better understand where sediments are coming from, Lobb and his colleagues from the University of Manitoba and the University of Northern British Columbia use a technique called color fingerprinting. The color of a particular sediment is key to identifying the specific origin of the erosion. "It's not as particular as fingerprinting in a crime scene investigation," says Lobb, "but we have the tools to get a sophisticated identification of the sources of sediments."

At first glance, the color fingerprinting technique is fairly intuitive. It's also cheap and quick. "In the most simple case, black sediment is from surface sources and light sediment is from subsurface," says Lobb, "That's an oversimplification of a very precise process backed up by statistical models."

The distinction between surface and subsurface sediment sources is important. Subsurface sediment, or subsoil, is usually pulled by the water from the sides or bottoms of streams. Surface sediment, or topsoil, is more than likely coming from farm fields, riparian areas, or forest floors.

South Tobacco Creek revealed some facts that complicate the picture of erosion, and the human role in the process of sedimentation.

"We found that nature is more often to blame for a lot of the sediments we see in our streams," says Lobb, "Humans may not have as much of an effect on the amount of sediment flowing out of a watershed as we've been taught," says Lobb, "but we do have a profound effect on hydrology, and that can contribute to the erosion and sediment produced downstream."

Most of the sediment found in the South Tobacco Creek is from subsurface sources. It's coming from the stream banks and the huge rock walls that borders the creek as it cuts through a 600-foot escarpment. "Most people assumed sedimentation is caused by erosion in farm fields," says Lobb. "But one of the biggest culprits is the natural channel erosion that is constantly taking place."

The color coding technique makes it simple to find the geographic origin of sediment. "What to do with these answers is not as simple," say Lobb, "but precise color fingerprinting allows technology to open up to new directions. We are now looking at managing runoff from farm fields as being as important as managing erosion and sediment losses from farm fields. And, we are looking at managing runoff and erosion from the farm field scale to the watershed scale."

One of the complications is scale. Watersheds are dynamic. The health of one section of stream or river affects another section. To address issues at the watershed level requires looking at the area as a whole. In the case of Lake Winnipeg, the watershed spans an area 40 times the size of the lake itself.

"The public is demanding actions and impacts on a watershed scale," says Lobb. "Therefore, practices and processes have to reflect that larger regional scale."

###

Read the results of the study in the Journal of Environmental Quality.

Susan Fisk | EurekAlert!

Further reports about: Agronomy Canada downstream fingerprinting nutrients phosphorus sedimentation

More articles from Agricultural and Forestry Science:

nachricht New 3-D model predicts best planting practices for farmers
26.06.2017 | Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign

nachricht Fighting a destructive crop disease with mathematics
21.06.2017 | University of Cambridge

All articles from Agricultural and Forestry Science >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Can we see monkeys from space? Emerging technologies to map biodiversity

An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.

Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...

Im Focus: Climate satellite: Tracking methane with robust laser technology

Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.

Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...

Im Focus: How protons move through a fuel cell

Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.

As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...

Im Focus: A unique data centre for cosmological simulations

Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.

With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...

Im Focus: Scientists develop molecular thermometer for contactless measurement using infrared light

Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine

Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Plants are networkers

19.06.2017 | Event News

Digital Survival Training for Executives

13.06.2017 | Event News

Global Learning Council Summit 2017

13.06.2017 | Event News

 
Latest News

Supersensitive through quantum entanglement

28.06.2017 | Physics and Astronomy

X-ray photoelectron spectroscopy under real ambient pressure conditions

28.06.2017 | Physics and Astronomy

Mice provide insight into genetics of autism spectrum disorders

28.06.2017 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>