Gizmorama - August 6, 2018
An alternative plastic has been developed as a replacement for polyethylene; and they can be eaten away by microbes in the soil. So long, plastic bottles!
Learn about this and more interesting stories from the scientific community in today's issue.
Until Next Time,
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*-- Soil microbes eat alternative plastic, study shows --*
New research shows an alternative plastic called PBAT -- short for poly(butylene adipate-co-terephthalate) -- can be broken down by microbes in the soil.
Researchers hope the material can serve as a replacement for polyethylene mulch films. Large amounts of PE films are spread cross agricultural fields to boost crop yields by elevating soil temperature and keeping moisture in the ground.
Disposing of the plastic sheeting is difficult and, inevitably, large amounts of the plastic end up accumulating in the soil. Polyethylene contamination can disrupt water transportation and ultimately degrade soil health.
Researchers at ETH Zurich wanted to find out if a polymer alternative like PBAT would be more eco-friendly. The polymer had been deemed biodegradable for composting, but not for use in agriculture.
For their experiment, scientists synthesized PBAT with a precise amount of carbon-13 isotope. This allowed researchers to track the breakdown of carbon along various biodegradation pathways.
In soil samples, scientists were able to track the conversion of the polymer's carbon into boimass and energy production, as well as the byproduct CO2.
"The beauty of our study is that we used stable isotopes to precisely track PBAT-derived carbon along different biodegradation pathways of the polymer in the soil," ETH researcher Michael Zumstein said in a news release.
Zumstein and his colleagues -- who detailed their work this week in the journal Science Advances -- claim their study is the first to show a plastic is truly biodegradable in the soil.
"By definition biodegradation demands that microbes metabolically use all carbon in the polymer chains for energy production and biomass formation -- as we now demonstrated for PBAT," said Hans-Peter Kohler, environmental microbiologist at Eawag. "Many plastic materials simply crumble into tiny fragments that persist in the environment as microplastics -- even if this plastic is invisible to the naked eye."
Researchers say they're still a long way from curbing the pollution caused by the the global plastics industry, but that plastic biodegradability is a step in the right direction.
*-- Paleontologists find better way to bake synthetic fossils --*
Scientists have found a better way to accelerate the fossilization process in the lab. The new methodology promises to produce more realistic synthetic fossils, useful for comparisons with the real thing.
Usually, the process of fossilization takes thousands, if not millions, of years. But scientists have developed a new and improved way to replicate the heat, pressure and chemical reactions that result from millennia spent underground.
To speed up geologic time in the lab, Evan Saitta, a paleontologist with the Field Museum and the University of Bristol, and his research partner Tom Kaye, from the Foundation for Scientific Advancement, took bits of modern bird, lizard and plant samples and packed them into tiny clay tablets with a hydraulic press.
The duo then placed the tablets in a sealed metal tube inside an oven, subjecting them to 410 degrees Fahrenheit and 3,500 psi pressure. After 24 hours, they retrieved the tablets and analyzed the plant and animal remains.
"We were absolutely thrilled," Saitta said in a news release, speaking of the results. "We kept arguing over who would get to split open the tablets to reveal the specimens. They looked like real fossils -- there were dark films of skin and scales, the bones became browned. Even by eye, they looked right."
Previous attempts to replicate the fossilization process have mostly relied on small, sealed chambers that not only trap in the organic molecules of interest, but the decaying byproducts of less stable molecules. The presence of these particles, which would never survive the real fossilization process, interfere with the ability of scientists to compare synthetic and natural fossil for scientific purposes.
Kaye helped Saitta develop a process that would allow volatile degradation products to escape. They duo realized the missing element was sediment. By embedding the material in clay, they were able to offer an escape route for the interfering particles.
"The sediment acts as a filter allowing unstable molecules to escape from the sample, revealing browned, flattened bones surrounded by dark, organic films where soft tissues once were," Saiita said in a University of Bristol news release.
Researchers believe their technology -- detailed this week in the journal Paleontology -- will allow scientists to test their hypothesis about the survivability of and effects of decay on different types of plant and animal material.
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