Rapid fluctuations in oxygen levels coincided with Earth’s first mass extinction

Nevin Kozik during fieldwork to investigate how rapid changes in marine oxygen levels may have played a significant role in driving Earth’s first mass extinction.
Photo Credit: Courtesy of Nevin Kozik

Rapid changes in marine oxygen levels may have played a significant role in driving Earth’s first mass extinction, according to a new study led by Florida State University researchers.

About 443 million years ago, life on Earth was undergoing the Late Ordovician mass extinction, or LOME, which eliminated about 85% of marine species. Scientists have long studied this mass extinction and continue to investigate its possible causes, such as reduced habitat loss in a rapidly cooling world or persistent low-oxygen conditions in the oceans.

By measuring isotopes of the element thallium — which shows special sensitivity to changes in oxygen in the ancient marine environment — the research team found that previously documented patterns of this mass extinction coincided with an initial rapid decrease in marine oxygen levels followed by a rapid increase in oxygen. Their work is published online in the journal Science Advances.

“Paleontologists have noted that there were several groups of organisms, such as graptolites and brachiopods, that started to decline very early in this mass extinction interval, but we didn’t really have any good evidence of an environmental or climate signature to tie that early decline of these groups to a particular mechanism,” said co-author Seth Young, an associate professor in the Department of Earth, Ocean and Atmospheric Science. “This paper can directly link that early phase of extinction to changes in oxygen. We see a marked change in thallium isotopes at the same time these organisms start their steady decline into the main phase of the mass extinction event.”

Turning Wastewater into Fertilizer Is Feasible and Could Help to Make Agriculture More Sustainable

Photo Credit: Franck Barske

The wastewater draining from massive pools of sewage sludge has the potential to play a role in more sustainable agriculture, according to environmental engineering researchers at Drexel University. A new study, looking at a process of removing ammonia from wastewater and converting it into fertilizer, suggests that it’s not only technically viable, but also could help to reduce the environmental and energy footprint of fertilizer production — and might even provide a revenue stream for utilities and water treatment facilities.

A Sustainable Nitrogen Source

The production of nitrogen for fertilizer is an energy-intensive process and accounts for nearly 2% of global carbon dioxide emissions. In the last several years researchers have explored alternatives to the Haber-Bosch nitrogen production process, which has been the standard for more than a century. One promising possibility, recently raised by some water utility providers, is gleaning nitrogen from the waste ammonia pulled from water during treatment.

“Recovering nitrogen from wastewater would be a desirable alternative to the Haber-Bosch process because it creates a ‘circular nitrogen economy,’” said Patrick Gurian, PhD, a professor in Drexel's College of Engineering who helped lead the research, which was recently published in the journal Science of the Total Environment. “This means we are reusing existing nitrogen rather than expending energy and generating greenhouse gas to harvest nitrogen from the atmosphere, which is a more sustainable practice for agriculture and could become a source of revenue for utilities.”

Toxins force construction of ‘roads to nowhere’

This image shows the effects of the toxin VopF, depicted in green in the cell on the left, on actin filaments, depicted in magenta in both cells.
Image Credit: Elena Kudryashova

Toxins released by a type of bacteria that cause diarrheal disease hijack cell processes and force important proteins to assemble into “roads to nowhere,” redirecting the proteins away from other jobs that are key to proper cell function, a new study has found.

The affected proteins are known as actins, which are highly abundant and have multiple roles that include helping every cell unite its contents, maintain its shape, divide and migrate. Actins assemble into thread-like filaments to do certain work inside cells.

Researchers found that two toxins produced by the Vibrio genus of bacteria cause actins to start joining together into these filaments – which could be thought of as cellular highways on which cargo is delivered – at the wrong location inside cells, and headed in the wrong direction.

New carbon nanotube-based foam promises superior protection against concussions

Postdoctoral research associate Komal Chawla studies the architected vertically aligned carbon nanotube foam in the lab.
Photo Credit: Joel Hallberg

Developed by University of Wisconsin–Madison engineers, a lightweight, ultra-shock-absorbing foam could vastly improve helmets designed to protect people from strong blows.

The new material exhibits 18 times higher specific energy absorption than the foam currently used in U.S. military combat helmet liners, as well as having much greater strength and stiffness, which could allow it to provide improved impact protection.

Physical forces from an impact can inflict trauma in the brain, causing a concussion. But helmet materials that are better at absorbing and dissipating this kinetic energy before it reaches the brain could help mitigate, or even prevent, concussions and other traumatic brain injuries.

The researchers’ industry partner, helmet manufacturer Team Wendy, is experimenting with the new material in a helmet liner prototype to investigate its performance in real-world scenarios.

“This new material holds tremendous potential for energy absorption and thus impact mitigation, which in turn should significantly lower the likelihood of brain injury,” says Ramathasan Thevamaran, a UW–Madison professor of engineering physics who led the research.

The team detailed its advance in a paper recently published online in the journal Extreme Mechanics Letters.

Are Covid-19 “comas” signs of a protective hibernation state?

Caption:When the painted turtle hibernates it essentially sedates its brain to survive in its low-oxygen environment. Authors of a new paper in PNAS hypothesize that the same dynamic may be occurring in severe Covid-19 patients who underwent sedation and ventilation.
Photo Credit: Wayne

Many Covid-19 patients who have been treated for weeks or months with mechanical ventilation have been slow to regain consciousness even after being taken off sedation. A new article in the Proceedings of the National Academy of Sciences offers the hypothesis that this peculiar response could be the effect of a hibernation-like state invoked by the brain to protect cells from injury when oxygen is scarce.

A very similar kind of state, characterized by the same signature change of brain rhythms, is not only observed in cardiac arrest patients treated by chilling their body temperature, a method called “hypothermia,” but also by the painted turtle, which has evolved a form of self-sedation to contend with long periods of oxygen deprivation, or “anoxia,” when it overwinters underwater.

“We propose that hypoxia combined with certain therapeutic maneuvers may initiate an as-yet-unrecognized protective down-regulated state (PDS) in humans that results in prolonged recovery of consciousness in severe Covid-19 patients following cessation of mechanical ventilation and in post-cardiac arrest patients treated with hypothermia,” wrote authors Nicholas D. Schiff and Emery N. Brown. “In severe Covid-19 patients we postulate that the specific combination of intermittent hypoxia, severe metabolic stress and GABA-mediated sedation may provide a trigger for the PDS.”

Brain-Powered Wheelchair Shows Real-World Promise

Source/Credit: The University of Texas at Austin

In one of the first studies of its kind, several people with motor disabilities were able to operate a wheelchair that translates their thoughts into movement.

The study by researchers at The University of Texas at Austin and published today in the journal iScience is an important step forward for brain-machine interfaces — computer systems that turn mind activity into action. The concept of a thought-powered wheelchair has been studied for years, but most projects have used non-disabled subjects or stimuli that leads the device to more or less control the person rather than the other way around.

In this case, three individuals with tetraplegia, the inability to move their arms and legs due to spinal injuries, operated the wheelchair in a cluttered, natural environment to varying degrees of success. The interface recorded their brain activity, and a machine-learning algorithm translated it into commands that drove the wheelchair.

The researchers said this is a sign of future commercial viability for mind-powered wheelchairs that can assist people with limited motor function.

Researchers may have found a new biomarker for covid-19

Patients with acute COVID-19 infection have increased levels of the cytokine IL-26 in their blood.
Photo Credit: Louis Reed

Researchers at Karolinska Institutet have shown that patients with acute COVID-19 infection have increased levels of the cytokine IL-26 in their blood. Moreover, high IL-26 levels correlate with an exaggerated inflammatory response that signifies severe cases of the disease. The findings, which are presented in Frontiers in Immunology, indicate that IL-26 is a potential biomarker for severe COVID-19.

Vaccines for SARS-CoV-2 have proved effective at reducing the number of cases of severe COVID-19. However, the emergence of new viral variants, limited distribution of the vaccine and declining immunity are problems that drive scientists to find more efficacious treatments for the disease.

“We need to understand more about underlying immunological mechanisms in order to find better treatments. There is also a need for improved diagnostics in COVID 19-patients,” says Eduardo Cardenas, postdoc researcher at the Institute of Environmental Medicine, Karolinska Institutet, and principal author of the new pilot study.

How does radiation travel through dense plasma?

A NASA image of plasma bursting from the sun. Plasma—a hot soup of atoms with free moving electrons and ions—is the most abundant form of matter in the universe, found throughout our solar system in the sun and other planetary bodies. A new study from University of Rochester researchers provides experimental data about how radiation travels through dense plasmas, which will help scientists to better understand planetary science and fusion energy.
Credit: NASA

First-of-its-kind experimental evidence defies conventional theories about how plasmas emit or absorb radiation.

Most people are familiar with solids, liquids, and gases as three states of matter. However, a fourth state of matter, called plasmas, is the most abundant form of matter in the universe, found throughout our solar system in the sun and other planetary bodies. Because dense plasma—a hot soup of atoms with free-moving electrons and ions—typically only forms under extreme pressure and temperatures, scientists are still working to comprehend the fundamentals of this state of matter. Understanding how atoms react under extreme pressure conditions—a field known as high-energy-density physics (HEDP)—gives scientists valuable insights into the fields of planetary science, astrophysics, and fusion energy.

One important question in the field of HEDP is how plasmas emit or absorb radiation. Current models depicting radiation transport in dense plasmas are heavily based on theory rather than experimental evidence.

“This work reveals fundamental steps for rewriting current textbook descriptions of how radiation generation and transport occurs in dense plasmas.”

Tick-borne pathogens increasingly widespread in Central Canada

Image Credit: 13smok

Tick-borne pathogens, known for causing illnesses such as Lyme disease, are on the rise in Central Canada – presenting new risks in areas where they were never previously detected.

The findings from researchers at McGill University and the University of Ottawa demonstrate the need for more comprehensive testing and tracking to detect the spread and potential risk of tick-borne pathogens to human and wildlife populations throughout Canada.

“Most people know that diseases can be transmitted to humans through the bite of infected ticks. Ticks can carry and spread several disease agents, called pathogens, that can make people and animals sick,” explains Kirsten Crandall, a PhD candidate under the joint supervision of McGill University Professor Virginie Millien and University of Ottawa Professor Jeremy Kerr.

“While the bacteria that causes Lyme disease is the most common tick-borne pathogen in Canada, other tick-borne pathogens are moving in,” she adds.

To investigate the presence and prevalence of several emerging tick-borne pathogens, Crandall and her team analyzed small mammals and ticks collected in Ontario and Quebec. The researchers found that five emerging pathogens were present across their study sites in Central Canada, including the pathogens causing Lyme disease and babesiosis, a malaria-like parasitic disease.

‘Lost’ pigeon found after more than a century

Video Credit: Jason Gregg, American Bird Conservancy

A September expedition to Papua New Guinea confirmed via video the existence of the black-naped pheasant pigeon, a critically endangered species that has not been reported for 140 years.

“For much of the trip, it seemed like we had no chance of finding this bird,” said Jordan Boersma, co-leader of the expedition and a postdoctoral researcher at the Cornell Lab of Ornithology. “We were just two days away from the end of our time on Fergusson Island in Papua New Guinea when one of our remote cameras recorded the bird walking around and fanning its tail.”

The group captured the first-ever video and still photos of the bird, a large ground-dwelling species with a rust-colored back, a black head and body, and a bobbing pheasant-like tail. It may only exist far inland on Fergusson Island in hot, extremely rugged geothermal terrain laced with twisty rivers and dense with biting insects and leeches.

“After a month of searching, seeing those first photos of the pheasant pigeon felt like finding a unicorn,” said John C. Mittermeier, director of the Search for Lost Birds project at American Bird Conservancy and a core member of the expedition team. “It’s the kind of moment you dream about your entire life as a conservationist and birdwatcher.”