As we head into finals season, read our last science news review piece of the semester to learn the biggest science headlines from this past week! This week sees records being broken, new studies on star deaths and innovative food technologies.
Oldest DNA provides insight into a 2 million-year-old ecosystem
Scientists recently discovered fragments of environmental DNA preserved in ice from 2 million years ago at the Kap København Formation in Greenland, breaking the previous record for oldest DNA by a million years. The team of researchers — led by University of Copenhagen Professor of Geogenetics Kurt Kjær — have been looking for DNA at Kap København since 2006. The newly discovered DNA provides a look into the ecosystem of Northern Greenland at the time. Findings published on Dec. 7 indicate that the temperature was much warmer than now, supporting forests of poplar, birch and thuja trees with animals like mastodons, geese and horseshoe crabs. In total, DNA fragments from 102 plants (24 of which are new) and 39 other species have been unearthed.
The sediments containing the DNA revealed that these layers originated from before the Earth flipped its magnetic field, meaning the DNA is at least 2 million years old, but it could potentially be older. Other evidence of the DNA’s age are differences between the ancient birch tree DNA and the modern species. Scientists hope to further study this period to get a better understanding of how climate change has and will affect the Arctic.
Scientists develop the new toughest material
Scientists at Lawrence National Berkeley Laboratory and Oak Ridge National Laboratory created a new material that has the highest toughness ever measured. The new material is a metallic alloy of chromium, cobalt and nickel (CrCoNi). Most alloys use one element as the majority of the material and add small amounts of other elements to reinforce the strength. However, CrCoNi is a high-entropy alloy, meaning there is an equal amount of each element in the material. These alloys tend to have high strength and ductility, which historically have been two competing properties. Another unique aspect of this material is that it gets stronger as it gets colder. One of the reasons for CrCoNi’s strength is its crystal structure. The unique combination of nanotwinning, where the lattice flips its structure due to defects, and the rearrangement of the lattice, with its hexagonal close packing, make it so difficult to break the material.
Messy death of star forms Southern Ring Nebula
Images of the Southern Ring Nebula, NGC 3132, were among the first images released by the James Webb Space Telescope (JWST). On Dec. 8, an international team of astronomers pieced together the messy death of many stars that occurred 2500 years ago to lead to this formation. The star was three times as massive as the Sun but was only 500 million years old, fairly young in star years. Scientists concluded two companion stars sped up the death of this star by causing departures from the main star’s spherical symmetry. When the star died, it ejected shrouds of gas in specific directions dictated by the companion stars’ locations. The core of the main star formed a white dwarf with half of the mass of the Sun and a volume the size of Earth. After using the JWST to analyze the nebulae, the researchers continue to study the implications of their finding on supernovae and gravitational wave systems.
Bacteriophages used as food decontaminant
Researchers at McMaster University developed a method to modify and crosslink bacteriophages to create a spray that can decontaminate food. Bacteriophages are a type of virus that infect and replicate in bacterial cells. They can be directed to attack harmful bacteria while leaving alone beneficial bacteria in food. By packaging this in a food-safe spray, the bacteriophages multiply on contact with harmful bacteria. The team tested the spray on a multidrug-resistant strain of E. coli in lettuce and meat, which led to a six-log reduction in the E. coli population. Bacteriophages have already been approved to be used in food products by the U.S. Food and Drug Administration. The team is also currently investigating medical applications of the bacteriophage technology to be used as a disinfectant.