There’s room for improvement in a popular climate-smart agricultural practice

The promise for American agriculture is tantalizing: healthier soil, more carbon kept in the ground, less fertilizer runoff, and less need for chemicals. The reality of planting cover crops during the off-season – a much-touted and subsidized approach to climate change mitigation – is more complicated, according to new Stanford University-led research. The study, published Nov. 8 in Global Change Biology, reveals that cover cropping as currently done in a major U.S. crop-growing region reduces corn and soybean yields, and could lead to indirect environmental impacts from expanded cultivation to make up for the losses.

“Use of cover crops is rapidly spreading. We wanted to see how these new practices affect crop yields in the real world, outside of small-scale research plots,” said Jillian Deines, lead author of the study and a postdoctoral scholar in Stanford’s Center on Food Security and the Environment (FSE) at the time of the research.

“Agriculture is a very tricky business to get right, and things typically don’t work out as planned” added senior author David Lobell, the Gloria and Richard Kushel Director of FSE and professor in Earth System Science. “Our view is that constant monitoring, evaluation, and learning is a key part of making agriculture truly sustainable.”

Zero Gravity Helps Create Homogeneous Material Structure

The mathematical model of the UrFU scientists helps to simulate the solidification process of an alloy. Credit: unsplash.com / Dan Cristian Pădureț

In space, due to the absence of gravity, metal hardens more homogeneously than on Earth. This was discovered by physicists who calculated the solidification process of aluminum-nickel metal alloys. Alloys were not chosen by chance, as they are one of the most common and account for 20% of all metalworking in the world. The model was built based on experimental data: the results obtained for alloy samples in microgravity on board the International Space Station were compared with the results of samples processed in terrestrial conditions. The results of experiments and modeling are presented in the journal Acta Materialia.

All aluminum-based materials are produced from the liquid phase, which is the initial phase. The solidification process and the conditions present at the moment of solidification determine the microstructural state of the final part, the scientists explain. The model considers the effects of crystallization rate and supercooling on the formation of alloy structure and properties, and allows the correct prediction of the microstructure and the required mechanical and electrical properties of the alloy.

Waikīkī Beach studies reveal why shoreline is chronically eroding

Waikīkī Beach is at the center of Hawaiʻi’s tourism hub, with a valuation of $2.2 billion, according to a 2016 study. Two published studies from researchers at the University of Hawaiʻi at Mānoa’s Climate Resilience Collaborative (CRC) provide new understanding of how and why the iconic beach is chronically eroding—enabling coastal managers and policymakers to more effectively manage the coastline.

During a two-year study from 2018 to 2020 published in the journal Marine Geology that included weekly surveys, a research team led by CRC Geospatial Analyst Anna Mikkelsen, found that the beach is primarily dominated by longshore transport, meaning that sand is moved from one end of the beach to another. This is contrary to standard beach models that predict cross-shore transport where sand is moved from nearshore to an offshore section of the beach.

“Another surprising finding was that we did not find any clear seasonal signal,” said Mikkelsen. “Instead of seeing high volumes of sand in summer, and low volumes in winter, we saw consistently increasing beach volume the first 12 months of the study and then erosion of the beach the following 10 months.”

The researchers discovered that the primary environmental drivers controlling the amount of sand present and the width of the beach include wave energy from south swell and trade-wind generated waves, and the water level.

Tonga volcano had highest plume ever recorded, new study confirms

The Hunga Tonga–Hunga Haʻapai eruption as seen by Japan's Himawari-8 satellite on 15 January 2022. Top image: Eruption at 4:20 UTC (about 15 minutes into the eruption); Middle image: Eruption at 4:50 UTC (45 minutes into the eruption); Bottom image: Eruption at 5:40 UTC (1 hour 35 minutes into the eruption).
Resized Image using AI by SFLORG
Image credit: Simon Proud / STFC RAL Space / NCEO / JMA.

A new analysis led by Oxford University researchers has shown the devastating Hunga Tonga–Hunga Haʻapai eruption in January 2022 created the tallest volcanic plume ever recorded. The research has been published in the journal Science.

At 57km high (35 miles), the ash cloud generated by the eruption is also the first to have been observed in the mesosphere, a layer of the atmosphere more commonly associated with shooting stars. The previous record-holder, the 1991 eruption of Mount Pinatubo in the Philippines, caused a plume was recorded as 40km high, although accurate satellite images, such as those taken over Tonga, were not available at the time.

The Tonga eruption took place under the sea, around 65km from the country’s main island, causing tsunamis felt as far away as Russia, the United States, and Chile. The waves claimed six lives, including two people in Peru, 10,000km away.

‘It’s the first time we’ve ever recorded a volcanic plume reaching the mesosphere. Krakatau in the 1800s might have done as well, but we didn’t see that in enough detail to confirm,’ said Dr Simon Proud, a National Centre for Earth Observation senior scientist at the University of Oxford and the Science and Technology Facilities Council’s RAL Space facility.

How magnetism could help explain Earth’s formation

Artist's impression of massive impact with proto-Earth.
Image Credit NASA/JPL.

A peculiar property of the Earth’s magnetic field could help us to work out how our planet was created 4.5 billion years ago, according to a new scientific assessment.

There are several theories about how the Earth and the Moon were formed, most involving a giant impact. They vary from a model where the impacting object strikes the newly formed Earth a glancing blow and then escapes, through to one where the collision is so energetic that both the impactor and the Earth are vaporized.

Our theoretical understanding of the Earth’s magnetic field today can actually tell us something about the very formation of the Earth-Moon system.

Now scientists at the University of Leeds and the University of Chicago have analyzed the dynamics of electrically conducting fluids and concluded that the Earth must have been magnetized either before the impact or as a result of it.

They claim this could help to narrow down the theories of the Earth-Moon formation and inform future research into what really happened.

Ocean microbes get their diet through a surprising mix of sources, study finds

Long thought to rely solely on photosynthesis, the microbe Prochlorococcus may get as much as one-third of its carbon through a second strategy: consuming the dissolved remains of other dead microbes. Illustration Credit: Jose-Luis Olivares, MIT

One of the smallest and mightiest organisms on the planet is a plant-like bacterium known to marine biologists as Prochlorococcus. The green-tinted microbe measures less than a micron across, and its populations suffuse through the upper layers of the ocean, where a single teaspoon of seawater can hold millions of the tiny organisms.

Prochlorococcus grows through photosynthesis, using sunlight to convert the atmosphere’s carbon dioxide into organic carbon molecules. The microbe is responsible for 5 percent of the world’s photosynthesizing activity, and scientists have assumed that photosynthesis is the microbe’s go-to strategy for acquiring the carbon it needs to grow.

But a new MIT study in Nature Microbiology today has found that Prochlorococcus relies on another carbon-feeding strategy, more than previously thought.

Organisms that use a mix of strategies to provide carbon are known as mixotrophs. Most marine plankton are mixotrophs. And while Prochlorococcus is known to occasionally dabble in mixotrophy, scientists have assumed the microbe primarily lives a phototrophic lifestyle.

The new MIT study shows that in fact, Prochlorococcus may be more of a mixotroph than it lets on. The microbe may get as much as one-third of its carbon through a second strategy: consuming the dissolved remains of other dead microbes.

The importance of light for grassland plant diversity

Light experiment at the Global Change Experimental Facility (GCEF) of the UFZ research station in Bad Lauchstädt.
Photo Credit: Anu Eskelinen / University of Oulu

Plants need light to grow. However, due to excess nutrients and/or the absence of herbivores less light can reach lower vegetation layers in grasslands. Consequently, few fast-growing species dominate and plant diversity declines. So far, this relationship has been established indirectly through experiments, but never directly by means of experimentally adding light in the field. Now, an international team of researchers including scientists from the Helmholtz Centre for Environmental Research (UFZ), the Martin Luther University Halle-Wittenberg (MLU) and the German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, was able to experimentally prove the dominant role of light competition for the first time. The results have been published in Nature.

The team of researchers led by Prof. Dr. Anu Eskelinen from the University of Oulu (Finland) used the Global Change Experimental Facility (GCEF) at the UFZ research station in Bad Lauchstädt for their experiments. Scientists from UFZ, iDiv and various universities use the GCEF platform to study the influence of different climate models and land use intensities on plant community structure - specifically food webs and interactions between species.

Arctic Hydrothermal Vent Site Could Help in Search for Extraterrestrial Life

The view from over ice-floes in the Arctic Ocean, covering the Aurora hydrothermal Field, Gakkel Ridge from the R/V Polarstern.
Photo Credit Chris German, ©Woods Hole Oceanographic Institution

When scientists discovered a hydrothermal vent site in the Arctic Ocean’s Aurora hydrothermal system in 2014, they did not immediately realize just how exciting their discovery was.

“Although finding any vent in the Arctic Ocean was a first, we figured what we had found was one of the least interesting kinds of vent sites that there are,” said Chris German, senior scientist with the Woods Hole Oceanographic Institution’s Department of Geology and Geophysics. “We came home from the expedition thinking, ‘Okay, we found a site in the Arctic. That’s great, but if you take away the ice-cover, it is just another vent site’.”

However, after further analysis and a follow-on 2019 expedition to the remote site, German and other researchers now think this is a very significant finding. They believe that this vent—and others still to be located within the Arctic Ocean’s Gakkel Ridge rift-valley floor—could change our understanding of ultra-slow spreading mid-ocean ridges, substantially expand the estimates of valuable marine mineral deposits rich in copper and gold and serve as natural laboratories to help inform the search for extraterrestrial life.

“Our findings have implications for ultra-slow ridge cooling, global marine mineral distributions, and the diversity of geologic settings that can host abiotic organic synthesis–pertinent to the search for life beyond Earth,” according to the paper, “Volcanically hosted venting with indications of ultramafic influence at Aurora hydrothermal field on Gakkel Ridge,” published in Nature Communications.

Learning to Better Understand the Language of Algae

A view through the microscope onto the diverse microalgal community of a freshwater lake, including diatoms, green algae and dinoflagellates/chryosphytes.
Photo: Maria Stockenreiter /LMU München

Communication is everything - and that applies for algae, too. However, their chemical language and its significance in aquatic ecosystems remain largely unknown. A research duo from the Helmholtz Centre for Environmental research (UFZ) and the Plymouth Marine Laboratory (PML) have published a corresponding review in Biological Reviews. This summarizes the current state of knowledge and identifies new approaches for future research in the language of algae and their ecological relationships.

Can algae talk? "Well, although they don't have any mouth or ears, algae still communicate with their own kind and with other organisms in their surroundings. They do this with volatile organic substances they release into the water," says Dr. Patrick Fink, a water ecologist at the UFZ's Magdeburg site. These chemical signals are known as BVOCs (biogenic volatile organic compounds) and are the equivalent of odors in the air with which flowering plants communicate and attract their pollinators. When under attack by parasites, some plant species release odors that attract the parasites' natural enemies to them. "Algae also employ such interactions and protective mechanisms," says Fink. "After all, they are among the oldest organisms on Earth, and chemical communication is the most original form of exchanging information in evolutionary history. However, our knowledge in this area still remains very fragmentary."

Habitat mapping data can fill gaps in knowledge on biodiversity

Dry sand heaths are also among the biotopes found in Hamburg.
Photo Credit: Christiane Buchwald

Data gathered by habitat mapping programs can make important contributions to biodiversity research. They provide insight into changes of the local flora since the 1980s – a period that is covered by hardly any other sources of information. A team from the Martin Luther University Halle-Wittenberg and the Hamburg Authorities for the Environment, Climate, Energy and Agriculture has now shown how research can benefit from this historic habitat mapping data using habitat maps of the city and federal state of Hamburg as an example. Their results, which have been published in "Ecosphere", also show a clear decline of species-rich habitats due to urbanization over the last decades.

In Germany, habitat mapping programs (Biotopkartierungen) have been carried out in almost every federal state since the 1980s. Similar sources exist in many other European countries. "The mapping programs are carried out by the authorities to obtain an overview of natural and semi-natural habitats for landscape planning and nature conservation," says Lina Lüttgert from the Institute of Biology of MLU. These datasets contain comprehensive data on all habitats of the local flora and fauna. Often, they also include information on the plant species found in these areas. This makes the data interesting for research: "They can provide insight into the changes over the last decades. Also, we do not have any other systematic surveys on local diversity from that period," says Lüttgert.

Violent supershear earthquakes are more common than previously thought

A section of the San Andreas Fault between Bakersfield and Santa Barbara, California. UCLA’s Lingsen Meng said the reason relatively few supershear earthquakes were reported previously is that researchers tended not to count those that occur underwater.
Photo Credit: Carol M. Highsmith/Library of Congress 

Powerful supershear earthquakes, once considered rare, are much more common than previously thought, according to a study led by UCLA geophysicists and published in Nature Geoscience.

The scientists analyzed all 6.7-or-greater magnitude strike-slip earthquakes worldwide since 2000 — there were 87 in all — and identified 12 of the supershear type, or about 14%. (Four of those earthquakes were previously unreported.)

That percentage is more than double what scientists expected; until now less than 6% of strike-slip earthquakes had been identified as supershear.

Strike-slip earthquakes occur when the edges of two tectonic plates rub sideways against each other. Supershear quakes are a subtype of that group that are caused when faults beneath the surface rupture faster than shear waves — the seismic waves that shake the ground back and forth — can move through rock. The effect corrals energy that is then released violently; the effect can be compared to a sonic boom.

As a result, supershear earthquakes tend to cause more shaking, and are potentially more destructive, than other earthquakes that have the same magnitude.

A better way to tell which species are vulnerable

Intertidal ecosystems containing species of mussels, barnacles, and algae were one of the systems with fluctuating populations analyzed by the team. They developed a new way to detect species that are vulnerable to perturbations, such as waves and storms that affect intertidal ecosystems.
Credits: Courtesy of the researchers | Massachusetts Institute of Technology

Wildfires, floods, pollution, and overfishing are among the many disruptions that can change the balance of ecosystems, sometimes endangering the future of entire species. But evaluating these ecosystems to determine which species are most at risk, in order to focus preservation actions and policies where they are most needed, is a challenging task.

Most such efforts assume that ecosystems are essentially in a state of equilibrium, and that external perturbations cause a temporary shift before things eventually return to that equilibrium state. But that assumption fails to account for the reality that ecosystems are often in flux, with the relative abundances of their different components shifting on timetables of their own. Now, a team of researchers at MIT and elsewhere have come up with a better, predictive way of evaluating these systems in order to rank the relative vulnerabilities of different species, and to detect species that are under threat but could otherwise go unnoticed.

Contrary to conventional ways of making such rankings today, they found, the species with the lowest population numbers or the steepest decline in numbers — criteria typically used today — are sometimes not the ones most at risk.

The findings are reported today in the journal Ecology Letters, in a paper by MIT associate professor of civil and environmental engineering Serguei Saavedra, recent doctoral student Lucas Medeiros PhD ’22, and three others.

Nestling birds recognize their local song ‘dialect’

The researchers discovered that the juvenile flycatchers clear response to their own song dialect helped them avoid learning songs from other species in the environment.
Photo credit: Tom Wallis

A recent study, published in Current Biology, led by researchers at Stockholm University and Uppsala University, has shown that juvenile songbirds react to hearing the songs they will eventually produce as adults, even when they are as young as 12 days old. Experiments conducted on nestling pied flycatchers across Europe demonstrate that they preferentially respond to songs from their own species and, remarkably, their own population.

Like human children learning language, juvenile songbirds learn their songs by listening to those produced by their parents and other adults. In both human language and songbird song, the learning process gives rise to small changes from one generation to the next, which leads to characteristic differences among populations, called dialects.

Tree rings offer insight into devastating radiation storms

A University of Queensland study has shed new light on a mysterious, unpredictable and potentially devastating kind of astrophysical event.

A team led by Dr Benjamin Pope from UQ’s School of Mathematics and Physics applied cutting edge statistics to data from millennia-old trees, to find out more about radiation ‘storms.

“These huge bursts of cosmic radiation, known as Miyake Events, have occurred approximately once every thousand years but what causes them is unclear,” Dr Pope said. “The leading theory is that they are huge solar flares.

“We need to know more, because if one of these happened today, it would destroy technology including satellites, internet cables, long-distance power lines and transformers.

“The effect on global infrastructure would be unimaginable.”

Enter the humble tree ring.

First author UQ undergraduate math student Qingyuan Zhang developed software to analyze every available piece of data on tree rings.

More yield, fewer species: How human nutrient intakes alter grasslands

Credit: Pete Linforth

High nutrient inputs in grassland lead to more plant species being lost than new ones can establish over longer periods of time. In addition, fewer new species settle than under natural nutrient availability. A worldwide experiment led by the German Centre for Integrative Biodiversity Research (iDiv), the Helmholtz Centre for Environmental Research (UFZ) and the Martin Luther University Halle-Wittenberg (MLU) has now been able to show why additional nutrient inputs reduce plant diversity in grasslands. The study published in "Ecology Letters", also sheds light on another issue: The increase in biomass with nutrient inputs is due to a few plant species that can use higher nutrient inputs to their advantage and remain successfully at a site over long periods of time.

One of the reasons for the global threat to biodiversity is that we humans introduce more nutrients into our environment than would naturally be present there, for example, when fertilizing agricultural land. In addition, precipitation re-distributes excess nutrients to other areas, and nutrients can also enter our soil through air pollution.

Natural grasslands are a habitat for many different plant species including grasses, herbs, wildflowers and orchids, many of which can be threatened by human activities and impacts. Plants need three things to grow: carbon dioxide (CO2) from the air, water and nutrients from the soil. The latter are usually scarce in semi-natural European meadows. Although this limits the growth of individual plants, it Favours the possibility of many different species growing side by side. Excessive amounts of nutrients, however, create the image that is ubiquitous in our landscape today: lush green meadows but without the colorful flowers of former times.

Using Carbon-Carbon Clumping to Detect the Signature of Biotic Hydrocarbons

The mystery of the origin of hydrocarbons found in extraterrestrial environment may finally be resolved, thanks to a technique developed by researchers at Tokyo Tech based on a 13C-13C abundance analysis. By measuring the abundance of clumped 13C-13C isotope in the hydrocarbons, it can be inferred if a hydrocarbon was produced via biological processes. This could open doors to distinguishing such hydrocarbons from abiotic ones, aiding our search for extra-terrestrial life.

An important signature of life is the existence of organic molecules that have originated from biological processes. The most common organic molecule found in all life forms are hydrocarbons. However, they need not be of biotic origin, i.e., produced from thermal decomposition of sedimentary organic matter or microbes. So, while hydrocarbons have been found in several places outside Earth, they are not necessarily indicative of extra-terrestrial life. These hydrocarbons could well have formed from abiotic, or non-biological processes. Therefore, finding out whether a hydrocarbon is of biotic or abiotic origin is key to inferring the existence of life. Unfortunately, this has proved to be a tremendously challenging task so far.

Deeper understanding of the icy depths

Frazil ice formed below the ocean surface drives the generation of cold dense water.
Photo credit: Masato Ito

Scientists have uncovered new details of how ice forming below the ocean surface in Antarctica provides cold dense water that sinks to the seabed in an important aspect of global water circulation.

The results, published in the journal Science Advances, come from a team at the Hokkaido University’s Institute of Low Temperature Science, its Arctic Research Center, and the Faculty of Fisheries science, working with scientists at Japan’s National Institute of Polar Research and Aerospace Exploration Agency.

The seas around Antarctica, where a large amount of sea ice is formed, are central to global ocean water circulation, linking the Atlantic, Pacific, and Indian oceans. When sea ice is formed, it rejects salt, therefore leaving dense, cold water that sinks to the seabed. This water, called Antarctic Bottom Water (AABW), is the coldest and densest water mass in the global circulation, flooding across most of the deep seafloor known as the global abyss. Since the global ocean circulation influences the global climate, it is important to understand the mechanism of AABW formation and how the formation will be impacted by global warming.

Converting Carbon Dioxide to Minerals Underground

Mineralizing carbon dioxide underground is a potential carbon storage method.
Credit: Illustration by Cortland Johnson | Pacific Northwest National Laboratory

A new high-profile scientific review article in Nature Reviews Chemistry discusses how carbon dioxide (CO2) converts from a gas to a solid in ultrathin films of water on underground rock surfaces. These solid minerals, known as carbonates, are both stable and common.

“As global temperatures increase, so does the urgency to find ways to store carbon,” said Pacific Northwest National Laboratory (PNNL) Lab Fellow and coauthor Kevin Rosso. “By taking a critical look at our current understanding of carbon mineralization processes, we can find the essential-to-solve gaps for the next decade of work.”

Mineralization underground represents one way to keep CO2 locked away, unable to escape back into the air. But researchers first need to know how it happens before they can predict and control carbonate formation in realistic systems.

“Mitigating human emissions requires fundamental understanding how to store carbon,” said PNNL chemist Quin Miller, co-lead author of the scientific review featured on the journal cover. “There is a pressing need to integrate simulations, theory, and experiments to explore mineral carbonation problems.”

Ecological imbalance: How plant diversity in Germany has changed in the past century

The cornflower is one of the "losers", its population has declined sharply over the past 100 years.
Photo Credit: André Künzelmann / UFZ

Germany's plant world has seen a greater number of losers than winners over the past one hundred years. While the frequencies and abundances of many species have shrunk, they have significantly increased in others. This has resulted in a very uneven distribution of gains and losses. It indicates an overall, large-scale loss of biodiversity, as a team lead by the Martin Luther University Halle-Wittenberg (MLU) and the German Centre for Integrative Biodiversity Research (iDiv) reports in the journal Nature.

It’s a weird paradox: While global biodiversity is lost at an alarming rate, at the local level, many studies are finding no significant decreases in animal and plant species numbers. "However, this doesn’t mean that the developments are not worrying," warns Professor Helge Bruelheide, an ecologist at MLU. After all, it also depends on which species we are talking about. For example, if survival artists that are specially adapted to peatlands or dry grasslands are displaced by common plants, the number of species often remains, in total, the same. However, diversity is still being lost because the once very distinct vegetation of different habitats is now becoming more and more similar.

To find out how strong this trend is in Germany, the team led by MLU looked at a multitude of local studies. Numerous experts provided data from more than 7,700 plots whose plant populations had been surveyed several times between 1927 and 2020. These studies, some of which have not been published before, cover a wide range of habitats and provide information on nearly 1,800 plant species. This includes about half of all the vascular plant species that grow in Germany. "Such time series can provide very valuable information," explains Dr Ute Jandt from MLU. This is because very precise botanical censuses can be conducted in plots that are often only ten or twenty square meters in size. ": It is highly unlikely that plants disappear or reappear unnoticed in such plots," Jandt adds.

Methane-Eating ‘Borgs’ Have Been Assimilating Earth’s Microbes

A digital illustration inspired by methane-eating archaea and the Borgs that assimilate them
Credit: Jenny Nuss/Berkeley Lab

In Star Trek, the Borg are a ruthless, hive-minded collective that assimilate other beings with the intent of taking over the galaxy. Here on nonfictional planet Earth, Borgs are DNA packages that could help humans fight climate change.

Last year, a team led by Jill Banfield discovered DNA structures within a methane-consuming microbe called Methanoperedens that appear to supercharge the organism’s metabolic rate. They named the genetic elements “Borgs” because the DNA within them contains genes assimilated from many organisms. In a study published today as the cover item in the journal Nature, the researchers describe the curious collection of genes within Borgs and begin to investigate the role these DNA packages play in environmental processes, such as carbon cycling.

First contact

Methanoperedens are a type of archaea (unicellular organisms that resemble bacteria but represent a distinct branch of life) that break down methane (CH4) in soils, groundwater, and the atmosphere to support cellular metabolism. Methanoperedens and other methane-consuming microbes live in diverse ecosystems around the world but are believed to be less common than microbes that use photosynthesis, oxygen, or fermentation for energy. Yet they play an outsized role in Earth system processes by removing methane – the most potent greenhouse gas – from the atmosphere. Methane traps 30 times more heat than carbon dioxide and is estimated to account for about 30 percent of human-driven global warming. The gas is emitted naturally through geological processes and by methane-generating archaea; however, industrial processes are releasing stored methane back into the atmosphere in worrying quantities.