Among those algae most closely related to land plants, diverse body types are found — ranging from single-celled algae to more complex cell filaments. From this group of relatives, an international group of researchers led by the Universities of Göttingen and Nebraska-Lincoln has now generated the first genome data of such complex specimens, on four filamentous “star algae” of the genus Zygnema. Their results were published in Nature Genetics.

The researchers worked with four algal strains in total, two from a culture collection in the USA and two that have been kept safe in the Algal Culture Collection at Göttingen University (SAG). The research involved more than 50 scientists from nine countries who combined a range of cutting-edge sequencing techniques to elucidate the entire DNA sequence of these algae. The advanced methods enabled them to generate complete genomes for these organisms at the level of whole chromosomes — something that had never been done before on this group of algae. Comparing the genes on the genomes with those of other plants and algae led to the discovery of specific overabundances of signalling genes and environmental response factors. Dr Iker Irisarri, Leibniz Institute for the Analysis of Biodiversity Change, explains: “Many of these genes underpin molecular functions that were important for the emergence of the first multicellular terrestrial plants. It is fascinating that the genetic building blocks, whose origins predate land plants by millions of years, duplicated and diversified in the ancestors of plants and algae and, in doing so, enabled the evolution of more specialized molecular machinery.”

Professor Jan de Vries, University of Göttingen, says: “Not only do we present a valuable, high-quality resource for the entire plant scientific community, who can now explore these genome data, our analyses uncovered intricate connections between environmental responses. This sheds light on one of land plants’ most important features: their ability to adjust their growth and development so that it aligns with the environment in which they dwell — a process known as developmental plasticity.”

Physics Experiment 1-A (PE1-A) is the first in a series of non-nuclear experiments that will compare computer simulations with high-resolution seismic, tracer gas, acoustic and electromagnetic data gleaned from underground explosions and atmospheric experiments, said Lawrence Livermore National Laboratory researcher Stephen Myers at the Seismological Society of America (SSA)’s 2024 Annual Meeting.

The 18 October explosion — the equivalent of 16.3 tons of TNT — took place in Aqueduct Mesa “P Tunnel” at the Nevada National Security Site (NNSS). Seismic, acoustic and electromagnetic waves from the shock were recorded by instruments near the explosion and with regional seismic networks, while gas tracers and chemical byproducts released into the resulting cavity and boreholes also were sampled by a dense instrument array. Seismic signals were recorded at least 250 kilometers away from the explosion.

“All of this is to help further our goal of monitoring nuclear explosions better and understanding the source physics of how those explosions generate seismic waves,” Myers said.

Physics Experiment 1 (PE1) is the latest research program at NNSS, where atmospheric nuclear tests took place between 1951 and 1962, and underground testing occurred between 1961 and 1992. More recently, programs like the Source Physics Experiment looked at a range of non-nuclear chemical explosions in different rock environments, collecting data to learn more about explosion physics.

The seven new experiments planned as part of PE1 include more underground chemical explosions under different emplacement conditions, as well as atmospheric experiments that attempt to track underground and atmospheric transport of gases produced in these types of explosions. The program will also use a large electromagnetic coil, about four meters wide, to generate pulses of electromagnetic energy inside the tunnel that can be measured at the ground surface, to determine how much of the electromagnetic signal from an underground nuclear test would be affected by traveling through the earth.

“There’s no one experiment that can generate all the signals that are produced by a nuclear shot, so we’re doing this series of seven to try to piece together all of those signals,” Myers explained, “so that we can validate our full physics codes that we use to simulate what all of those signals would be like from a nuclear explosion.”

Significant improvements in high-performance computing have allowed researchers like Myers to create increasingly realistic and complex explosion simulations, but “then the question is, ‘are they correct?’ And the only way we can be confident about that is to compare them to these high-resolution data sets from the experiments,” he said.

The new experiments are more heavily instrumented than older NNSS experiments, he noted, which helps to validate the computer code simulations.

Atmospheric simulations, for example, must account for complex variables such as temperature changes and air turbulence under different topographic conditions. With the experiments, Myers said, “we’re trying to get an idea if tracers came out of the ground after a nuclear test, exactly what some of these very local conditions, topography and other aspects, would affect the transport of those radionuclides and other telltale gases that could be released by an underground test.”

Myers said the seismic and acoustic data from PE1 will be released to a public seismic database after two years. “We want this to be a resource for the community as a whole.”

Dr Margaret M. Brennan, Research Assistant, Department of Public Health and Primary Care, School of Medicine, Trinity College and first author, said:

“We hope this work can highlight the significant differences in vitamin D levels among different ethnic groups at northern latitudes and contribute to efforts to address the long-standing population health issue of vitamin D deficiency.”

The authors analysed data from half a million participants from the United Kingdom (UK,) and for each person, they calculated the individualized estimate of ambient ultraviolet-B (UVB) level, which is the wavelength of sunlight that induces vitamin D synthesis in the skin.

A comprehensive analysis of key determinants of vitamin D and their interactions revealed novel insights. The first key insight is that ambient UVB emerges as a critical predictor of vitamin D status, even in a place like the UK, which receives relatively little sunlight. The second is that age, sex, body mass index (BMI), cholesterol level, and vitamin D supplementation significantly influence how individuals respond to UVB. For example, as BMI and age increase, the amount of vitamin D produced in response to UVB decreases.

Professor Lina Zgaga, Associate Professor of Epidemiology, Department of Public Health and Primary Care, School of Medicine, Trinity College and the principal investigator, said:

“We believe our findings have significant implications for the development of tailored recommendations for vitamin D supplementation. Our study underscores the need to move away from a one-size-fits-all approach towards personalized strategies for optimizing vitamin D status.”

Rasha Shraim, PhD candidate, Department of Public Health and Primary Care, School of Medicine, Trinity College, and co-principal investigator on this study said:

“Our study also highlights the effect that natural environmental factors, like sunlight, can have on our health. We hope that our approach encourages future researchers and public health bodies to integrate these factors into their health and disease work.”

The authors hope that their manuscript will contribute to the ongoing discourse on vitamin D supplementation guidelines.

Each year, roughly 2.47 billion gallons of lubricating oil are consumed in the United States alone for engines and industrial machinery, according to DOE, with about half eventually finding its way into the environment.

While environmentally acceptable lubricants are available, they are not optimized with additives that can greatly improve performance while posing minimal environmental impact if accidentally released. To create nontoxic, biodegradable and high-performing lubricant additives for water power turbines, researchers turned to ionic liquids, or ILs: organic liquid salts that mix well with oil, reduce friction between bearings and gears, and are stable in a range of temperatures.

A team of materials and environmental scientists at ORNL worked together to design, synthesize and test top-candidate ILs of ammonium phosphate and phosphonium phosphate that provide a good mix of properties.

When added to base oils, the ILs demonstrated 50% less friction and a tenfold decrease in equipment wear compared to a commercially available gear oil, while meeting federal standards for environmental toxicity and biodegradability, as described in ACS Sustainable Chemistry & Engineering

The project builds on more than 20 years of IL research at ORNL, including the development of lubricant additives designed to reduce engine wear and boost fuel economy in vehicles.

“Our previous work showed us that you could dramatically increase the performance of lubricants with the addition of just 1% or even a half-percent of ILs,” said ORNL’s Jun Qu, who leads the project and the Surface Engineering and Tribology group at ORNL.

This time around, scientists sought to create a nontoxic additive for use in turbines installed in aquatic environments, generating electricity using waves, tides, ocean and river currents. Although ILs are generally considered less toxic than conventional lubricant ingredients, their impact on the environment has not been closely studied.

“On the environmental side, there are three main factors we care about with these lubricants,” said Teresa Mathews, lead for the Biodiversity and Ecosystem Health group at ORNL. “They have to be highly performing, we don’t want them to be toxic to any aquatic organisms, and if there’s a spill, we don’t want the lubricants to be compounds that last in the environment. We want them to degrade very rapidly.”

Pursuing a cleaner formula

The team first sought to eliminate potential toxic elements such as fluorine and chlorine and metals such as zinc and iron from the candidate ILs. They also focused on creating ILs made up of shorter hydrocarbon chains — chains containing fewer than six carbon atoms — which are generally considered to be less toxic.

“We found a four-carbon chain to be the sweet spot,” Qu said. Going shorter than four carbons resulted in an IL that didn’t mix well with oil and was less thermally stable, he added.

Friction testing was accomplished with metal pieces simulating turbine gears and bearings coated with a lubricant containing the IL. Resulting surface wear of the pieces was characterized using electron microscopy at the Center for Nanophase Materials Sciences, a DOE Office of Science user facility at ORNL.

These particular ILs are fairly straightforward to produce and can be easily scaled up for commercialization, said Huimin Luo, a chemist in ORNL’s Manufacturing Science Division who led the chemical synthesis work.

To determine the additives’ environmental impact, ORNL ecotoxicologist Louise Stevenson conducted toxicity and biodegradability tests in ORNL’s Environmental Toxicology Laboratory, where assessments are routinely conducted for DOE, the Department of Defense and other agencies. Following Environmental Protection Agency protocols, the toxicity tests used Ceriodaphnia, tiny planktonic crustaceans commonly known as water fleas that sit at the bottom of the food chain, have a short life cycle and rapid reproduction rate, and are highly sensitive to environmental conditions.

Tiny plankton provide big insights

The organisms “are like canaries in a coal mine for aquatic toxicity because they are filter feeders and interact with a lot of water,” Stevenson said. “In a seven-day test, we’ll get three to four rounds of reproduction with daily hatching, so we can look for both lethal effects and sublethal effects such as reproductive and growth impacts that have an effect on population survival.”

While the environmentally acceptable lubricant base oils had no effect on the crustaceans, the commercial lubricant additives and two early IL compounds were found to be extremely toxic to the organisms, resulting in 100% mortality within one to three days after exposure. The team’s ultimate designs for short-chain ammonium phosphate and phosphonium phosphate IL additives resulted in 90-100% survival rates after seven days.

The final, top-performing IL-enhanced lubricants were also found to be highly biodegradable compared to standard lubricant additives. Testing involved exposing the compounds to aquatic microbes and then measuring the rate of carbon dioxide production as the microbes broke down the materials.

High-performing, environmentally friendly lubricants designed specifically for marine energy turbines are important for other reasons, including equipment durability. Lubricant technology currently in use for marine turbines was borrowed from wind turbines, which are serviced every six to 18 months, Qu said. But tidal turbines installed in the ocean or rivers are typically designed for service every six years and operate under much harsher conditions.

The project is expected to next focus on further development of IL lubricant additives specifically for use in tidal turbines operating in the ocean and exposed to potential seawater contamination and pressure and temperature extremes.