It’s possible that I shall make an ass of myself. But in that case one can always get out of it with a little dialectic. I have, of course, so worded my proposition as to be right either way (K.Marx, Letter to F.Engels on the Indian Mutiny)
New research has revealed a potentially important role ginger supplements can play in controlling inflammation for people living with autoimmune diseases.
The research published in JCI Insight focused on studying the impact of ginger supplementation on a type of white blood cell called the neutrophil. The study was especially interested in neutrophil extracellular trap (NET) formation, also known as NETosis, and what it may mean for controlling inflammation.
The study found ginger consumption by healthy individuals makes their neutrophils more resistant to NETosis. This is important because NETs are microscopic spider web-like structures that propel inflammation and clotting, which contribute to many autoimmune diseases, including lupus, antiphospholipid syndrome and rheumatoid arthritis.
"There are a lot of diseases where neutrophils are abnormally overactive. We found that ginger can help to restrain NETosis, and this is important because it is a natural supplement that may be helpful to treat inflammation and symptoms for people with several different autoimmune diseases," said senior co-author Kristen Demoruelle, MD, Ph.D., associate professor of medicine at the University of Colorado School of Medicine on the University of Colorado Anschutz Medical Campus.
In a clinical trial, the researchers found that daily intake of a ginger supplement for seven days (20 mg of gingerols/day) by healthy volunteers boosted a chemical inside the neutrophil called cAMP. These high levels of cAMP then inhibited NETosis in response to various disease-relevant stimuli.
"Our research, for the first time, provides evidence for the biological mechanism that underlies ginger's apparent anti-inflammatory properties in people," said senior co-author Jason Knight, MD, Ph.D., associate professor in the Division of Rheumatology at the University of Michigan.
The researchers say that many people with inflammatory conditions are likely to ask their health care providers whether natural supplements could be helpful for them or they already take supplements, like ginger, to help manage symptoms. Unfortunately, the precise impact on disease is often unknown.
The researchers hope that providing more evidence about ginger's benefits, including the direct mechanism by which ginger impacts neutrophils, will encourage health care providers and patients to more strategically discuss whether taking ginger supplements as part of their treatment plan could be beneficial.
"There are not a lot of natural supplements, or prescription medications for that matter, that are known to fight overactive neutrophils. We, therefore, think ginger may have a real ability to complement treatment programs that are already underway. The goal is to be more strategic and personalized in terms of helping to relieve people's symptoms," Knight adds.
As a next step, the researchers hope to undertake clinical trials of ginger in patients with autoimmune and inflammatory diseases where neutrophils are overactive, such as lupus, rheumatoid arthritis, antiphospholipid syndrome and even COVID-19.
More information: Ginger intake suppresses neutrophil extracellular trap formation in autoimmune mice and healthy humans, JCI Insight (2023).
Sex life discovery raises IVF hope for endangered purple cauliflower soft coral
by Meryl Larkin, David Harasti, Kirsten Benkendorff, Stephen D. A. Smith and Tom R Davis, The Conversation
The life cycle of the purple cauliflower coral Dendronephthya australis begins with an egg being fertilised by sperm, proceeds to embryo cell division within 2-4 hours, to fully grown larvae by day 5, to metamorphosis to polyp from 8 days of age. Credit: Meryl Larkin
Vital coastal habitat was destroyed in the devastating floods that hit New South Wales in 2021 and 2022.
The purple cauliflower soft coral Dendronephthya australis, now listed as an endangered species, was almost completely wiped out in the Port Stephens estuary and along the coast. That's a tragedy because this coral shelters young snapper and the endangered White's seahorse.
Unfortunately, a lack of knowledge hampered recovery efforts—until now.
In our new research we discovered how the coral reproduces. We used IVF (in-vitro fertilization) to create baby coral in the lab. And we successfully transplanted the coral into the wild. This offers new hope for the survival of the species.
Variety is the spice of life
Corals have a complicated sex life. There's more than one way to "do it". And gender varies too.
Corals can reproduce asexually, meaning they create genetic copies of themselves. This process often entails shedding polyps that can attach to reefs to form new colonies.
Using this process is a common approach for coral restoration. It's a bit like propagating plants. Cuttings or fragments are removed from adult colonies, briefly maintained in the lab, and then new corals are transplanted into the wild. This isn't a simple process for soft corals, though we have been exploring ways to make this work for Dendronephthya australis. Understanding the sex life of purple cauliflower soft coral offers hope for the species.
Many corals are hermaphrodites, which means they have both male and female reproductive organs. Others form colonies that are entirely male or female. And some mix or swap sexes.
Spawning is the release of eggs and sperm. Again, corals can use various techniques. Broadcast spawning is where eggs and sperm are released into the water column. Brooding is where eggs are fertilized within colonies and later released as larvae.
But until sexual reproduction of an individual species is observed, their sex life remains a private matter.
A chance discovery in the lab
We were growing coral in the lab, raising asexual clones from fragments, when we noticed something unusual.
There were small orange dots inside some of the corals. These were much larger than the grains of dry orange "coral food" we fed them. So they had to be something else.
Unfertilised eggs (orange dots) were observed in Dendronephthya australis fragments for the first time. Credit: Meryl Larkin
We soon realized the orange dots were unfertilised eggs. Half of the fragments in our care contained eggs. As sperm is much smaller, we had to sacrifice small portions of the remaining coral fragments for closer inspection of their contents (under a microscope). In doing this, we discovered the other half were sperm-bearing.
As fate would have it, we had collected fragments from two donor colonies—one female and one male. By chance, we discovered Dendronephthya australis is "gonochoric" (meaning colonies are either male or female).
We watched the corals carefully over the following weeks and made more discoveries. Females spawned (released their eggs) around the "neap tide" (when the moon appears half full) during the summer months.
Maybe the coral evolved to spawn when tidal currents are slowest, to maximize the chance of fertilization.
Coral IVF for making babies
We used IVF techniques to fertilize harvested eggs. Cell division occurred within hours. Mobile larvae grew over the following week.
Researchers achieved larval settlement, witnessing the change to the single polyp stage of the soft coral. Credit: David Harasti
From eight days of age, the larvae started to transform into polyps; we were the first people to witness these tiny cauliflower coral babies (as single polyps).
Within just a few weeks, we had produced 280 babies from just a few coral fragments.
Understanding how the purple cauliflower coral reproduces is important for several reasons:maintaining genetic diversity: if the sex ratio becomes unbalanced, the effective population size will be lower than the total number of remaining individuals achieving fertilization: broadcast spawning in corals is density-dependent. That means if more colonies are lost, the chance of natural sexual reproduction decreases restoring gender balance: any attempt to grow more coral from fragments will need to ensure both male and female colonies are represented scaling up production: sexual reproduction provides an opportunity to raise more baby corals while maintaining genetic diversity in the population.
Ongoing restoration work
Since this discovery, we have successfully repeated these IVF techniques. We transplanted hundreds of coral babies and released thousands of larvae back into Port Stephens.
Four-month-old juvenile coral transplanted in Port Stephens. Credit: Meryl Larkin
Early results suggest some IVF babies survived at least the first 18 months and performed better than the asexual fragments.
We plan to implement the IVF program annually. We're optimistic that we can boost the population of this endangered coral in ways never thought possible.
Historians race to find Great Lakes shipwrecks before quagga mussels destroy the sites
by Todd Richmond
This Aug. 17, 2021 photo shows Quagga mussels cover the engine of a Bell P-39 Airacobra military plane in Lake Huron, Mich., as maritime archaeologist Carrie Sowden, rear, documents the site. Archaeologists are scrambling to locate Great Lakes shipwrecks and downed planes before quagga mussels destroy them. Credit: Wayne Lusardi via AP
The Great Lakes' frigid fresh water used to keep shipwrecks so well preserved that divers could see dishes in the cupboards. Downed planes that spent decades underwater were left so pristine they could practically fly again when archaeologists finally discovered them.
Now, an invasive mussel is destroying shipwrecks deep in the depths of the lakes, forcing archaeologists and amateur historians into a race against time to find as many sites as they can before the region touching eight U.S. states and the Canadian province of Ontario loses any physical trace of its centuries-long maritime history.
"What you need to understand is every shipwreck is covered with quagga mussels in the lower Great Lakes," Wisconsin state maritime archaeologist Tamara Thomsen said. "Everything. If you drain the lakes, you'll get a bowl of quagga mussels."
Quagga mussels, finger-sized mollusks with voracious appetites, have become the dominant invasive species in the lower Great Lakes over the past 30 years, according to biologists.
The creatures have covered virtually every shipwreck and downed plane in all of the lakes except Lake Superior, archaeologists say. The mussels burrow into wooden vessels, building upon themselves in layers so thick they will eventually crush walls and decks. They also produce acid that can corrode steel and iron ships. No one has found a viable way to stop them.
Wayne Lusardi, Michigan's state maritime archaeologist, is pushing to raise more pieces of a World War II plane flown by a Tuskegee airman that crashed in Lake Huron in 1944.
"Divers started discovering (planes) in the 1960s and 1970s," he said. "Some were so preserved they could fly again. (Now) when they're removed the planes look like Swiss cheese. (Quaggas are) literally burning holes in them."
Quagga mussels, native to Russia and Ukraine, were discovered in the Great Lakes in 1989, around the same time as their infamous cousin species, zebra mussels. Scientists believe the creatures arrived via ballast dumps from transoceanic freighters making their way to Great Lakes ports.
Unlike zebra mussels, quaggas are hungrier, hardier and more tolerant of colder temperatures. They devour plankton and other suspended nutrients, eliminating the base level of food chains. They consume so many nutrients at such high rates they can render portions of the murky Great Lakes as clear as tropical seas. And while zebra mussels prefer hard surfaces, quaggas can attach to soft surfaces at greater depths, enabling them to colonize even the lakes' sandy bottoms.
After 30 years of colonization, quaggas have displaced zebra mussels as the dominant mussel in the Great Lakes. Zebras made up more than 98% of mussels in Lake Michigan in 2000, according to the University of California, Riverside's Center for Invasive Species Research. Five years later, quaggas represented 97.7%.
For wooden and metal ships, the quaggas' success has translated into overwhelming destruction.
The mussels can burrow into sunken wooden ships, stacking upon themselves until details such as name plates and carvings are completely obscured. Divers who try to brush them off inevitably peel away some wood. Quaggas also can create clouds of carbon dioxide, as well as feces that corrode iron and steel, accelerating metal shipwrecks' decay.
Quaggas have yet to establish a foothold in Lake Superior. Biologists believe the water there contains less calcium, which quaggas need to make their shells, said Dr. Harvey Bootsma, a professor at the University of Wisconsin-Milwaukee's School of Freshwater Sciences.
This Aug. 15, 2021 photo, videographer Nicholas Lusardi investigates the wing of a downed P-39 Airacobra in Lake Huron, Mich. The plane that crashed during a training mission in April 1944, killing Lt. Frank Moody, a Tuskegee airman. Archaeologists are racing to document Great Lakes shipwrecks and downed planes before quagga mussels disintegrate them. Credit: Wayne Lusardi via AP
That means the remains of the Edmund Fitzgerald, a freighter that went down in that lake during a storm in 1975 and was immortalized in the Gordon Lightfoot song, "The Ballad of the Edmund Fitzgerald," are safe, at least for now.
Lusardi, Michigan's state maritime archaeologist, ticked off a long list of shipwreck sites in the lower Great Lakes consumed by quaggas.
His list included the Daniel J. Morrel, a freighter that sank during a storm on Lake Huron in 1966, killing all but one of the 29 crew members, and the Cedarville, a freighter that sank in the Straits of Mackinac in 1965, killing eight crew members. He also listed the Carl D. Bradley, another freighter that went down during a storm in northern Lake Michigan in 1958, killing 33 sailors.
The plane Lusardi is trying to recover is a Bell P-39 that went down in Lake Huron during a training exercise in 1944, killing Frank H. Moody, a Tuskegee airman. The Tuskegee Airmen were a group of Black military pilots who received training at Tuskegee Army Air Field in Alabama during World War II.
Brendon Baillod, a Great Lakes historian based in Madison, has spent the last five years searching for the Trinidad, a grain schooner that went down in Lake Michigan in 1881. He and fellow historian Bob Jaeck finally found the wreck in July off Algoma, Wisconsin.
The first photos of the site, taken by a robot vehicle, showed the ship was in unusually good shape, with intact rigging and dishes still in cabins. But the site was "fully carpeted" with quagga mussels, Baillod said.
"It has been completely colonized," he said. "Twenty years ago, even 15 years ago, that site would have been clean. Now you can't even recognize the bell. You can't see the nameboard. If you brush those mussels off, it tears the wood off with it."
Quagga management options could include treating them with toxic chemicals; covering them with tarps that restrict water flow and starve them of oxygen and food; introducing predator species; or suffocating them by adding carbon dioxide to the water.
So far nothing looks promising on a large scale, UW-Milwaukee's Bootsma said.
"The only way they will disappear from a lake as large as Lake Michigan is through some disease, or possibly an introduced predator," he said.
That leaves archaeologists and historians like Baillod scrambling to locate as many wrecks as possible to map and document before they disintegrate under the quaggas' assaults.
At stake are the physical remnants of a maritime industry that helped settle the Great Lakes region and establish port cities such as Milwaukee, Detroit, Chicago and Toledo, Ohio.
"When we lose those tangible, preserved time capsules of our history, we lose our tangible connection to the past," Baillod said. "Once they're gone, it's all just a memory. It's all just stuff in books."
Artist’s concept of the Parker Solar Probe spacecraft approaching the sun. Launching in 2018, Parker Solar Probe will provide new data on solar activity and make critical contributions to our ability to forecast major space-weather events that impact life on Earth. Credit: NASA
NASA's Parker Solar Probe has racked up an impressive list of superlatives in its first five years of operations: It's the closest spacecraft to the sun, the fastest human-made object and the first mission to ever "touch the sun."
Now, Parker has one more feather to add to its sun-kissed cap: It's the first spacecraft ever to fly through a powerful solar explosion near the sun.
As detailed in a new study published Sept. 5 in The Astrophysical Journal—exactly one year after the event occurred—Parker Solar Probe passed through a coronal mass ejection (CME).
These fierce eruptions can expel magnetic fields and sometimes billions of tons of plasma at speeds ranging from 60 to 1,900 miles (100 to 3,000 kilometers) per second. When directed toward Earth, these ejections can bend and mold our planet's magnetic field, generating spectacular auroral shows and, if strong enough, potentially devastate satellite electronics and electrical grids on the ground.
Cruising on the far side of the sun just 5.7 million miles (9.2 million kilometers) from the solar surface—22.9 million miles (36.8 million kilometers) closer than Mercury ever gets to the sun—Parker Solar Probe first detected the CME remotely before skirting along its flank. The spacecraft later passed into the structure, crossing the wake of its leading edge (or shock wave), and then finally exited through the other side.
A composite of images collected by Parker Solar Probe’s Wide-field Imager for Solar Probe (WISPR) instrument captures the moment the spacecraft passed through a coronal mass ejection (CME) on Sept. 5, 2022. The event becomes visible at 0:14 seconds. The sun, depicted on the left, comes closest on Sept. 6, when Parker reached its 13th perihelion. The sound in the background is magnetic field data converted into audio. Credit: NASA/Johns Hopkins APL/Naval Research Laboratory/Brendan Gallagher/Guillermo Stenborg/Emmanuel Masongsong/Lizet Casillas/Robert Alexander/David Malaspina
In all, the sun-grazing spacecraft spent nearly two days observing the CME, providing physicists an unparalleled view into these stellar events and an opportunity to study them early in their evolution.
"This is the closest to the sun we've ever observed a CME," said Nour Raouafi, the Parker Solar Probe project scientist at the Johns Hopkins Applied Physics Laboratory (APL) in Laurel, Maryland, which built the spacecraft within NASA's timeline and budget, and currently manages and operates the mission. "We've never seen an event of this magnitude at this distance."
The CME on Sept. 5, 2022, was an extreme one. As Parker passed behind the shock wave, its Solar Wind Electrons, Alphas and Protons (SWEAP) instrument suite clocked particles accelerating up to 840 miles (1,350 kilometers) per second. Had it been directed toward Earth, Raouafi suspects it would have been close in magnitude to the Carrington Event—a solar storm in 1859 that is held as the most powerful on record to hit Earth.
"The potential damage of this class of event, large and very fast CMEs, can be colossal," Raouafi said.
Physicists have surmised that such an event today, if detected too late, could disable communications systems and spawn continent-wide blackouts.
Despite the eruption's power, Parker seemed unfazed. Its heat shield, radiators and thermal protection system ensured the Probe's temperatures never changed, said Jim Kinnison, the Parker Solar mission systems engineer at APL. Its autonomy system even triggered mitigation plans so the avionics suite worked without interruption. In fact, the only effect the CME had on the spacecraft was a slight torque—a tiny turn for which it quickly compensated.
"We knew from the beginning that Parker Solar Probe would fly through CMEs. That was part of the science objectives when the mission was established, so we designed the spacecraft from the start with an eye to surviving and, better yet, performing the science mission while in a CME," Kinnison said. "All in all, Parker proved itself to be robust and pretty tough, and all the hard work done in the design phase paid off."
Physicists have been interested in deciphering the forces that drive these stellar explosions and accelerate particles to such incredible clips. The only way to do that was to fly through one at the sun.
The science team determined the timeline of events and Parker's location during the CME by comparing measurements collected within the CME with those gathered outside it, including imagery taken by the Sun Earth Connection Coronal and Heliospheric Investigation (SECCHI) instrument on NASA's STEREO spacecraft. They built a simple model of the event, but given that nobody has ever taken measurements this early in a CME's development, some pieces were difficult to reconcile.
"You try simplified models to explain certain aspects of the event, but when you are this close to the sun, none of these models can explain everything," said Orlando Romeo, a space physicist at the University of California, Berkeley, and the lead author of the new study.
The team had determined three major intervals during the event, but piecing them together, Romeo said, was particularly confusing. Two sections they had seen before in CMEs when they arrived at Earth: the shock wave near the event's front followed by CME plasma, and another portion with magnetic and plasma characteristics typical of the sun's solar wind. But the third section—a low-density-region with slow-moving particles during the event—was new and odd.
"We're still not exactly sure what is happening there or how to connect it to the other two sections," Romeo said.
Advanced models that include more of the spacecraft's measurements will likely help, but passing through another CME would do even better. With the sun near the peak of its activity cycle, CMEs should happen more frequently. With a bit of luck, the team hopes, Parker Solar Probe will fly through several more ejections as it winds ever closer to the sun.
More information: O. M. Romeo et al, Near-Sun In Situ and Remote-sensing Observations of a Coronal Mass Ejection and its Effect on the Heliospheric Current Sheet, The Astrophysical Journal (2023). DOI: 10.3847/1538-4357/ace62e
A look through time with the James Webb Space Telescope. The big galaxy in the foreground is named LEDA 2046648, and is seen just over a billion years back in time, while most of the others lie even farther away, and hence are seen even further back in time. Credit: ESA/Webb, NASA & CSA, A. Martel
With the launch of the James Webb Space Telescope, astronomers are now able to peer so far back in time that we are approaching the epoch where we think that the first galaxies were created. Throughout most of the history of the universe, galaxies seemingly tend to follow a tight relation between how many stars they have formed, and how many heavy elements they have formed.
But for the first time we now see signs that this relation between the amount of stars and elements does not hold for the earliest galaxies. The reason is likely that these galaxies simply are in the process of being created, and have not yet had the time to create the heavy elements.
The universe is teeming with galaxies—immense collections of stars and gas—and as we peer deep into the cosmos, we see them near and far. Because the light has spent more time reaching us, the farther away a galaxy is, we are essentially looking back through time, allowing us to construct a visual narrative of their evolution throughout the history of the universe.
Observations have shown us that galaxies through the last 12 billion years—that is, 5/6 of the age of the universe—have been living their life in a form of equilibrium: There appears to be a fundamental, tight relation between on one hand how many stars they have formed, and on the other hand how many heavy elements they have formed. In this context, "heavy elements," means everything heavier than hydrogen and helium.
This relation makes sense, because the universe consisted originally only of these two lightest elements. All heavier elements, such as carbon, oxygen, and iron, was created later by the stars.
Imaging and spectroscopic data of CEERS-z7382. a, False-color JWST/NIRCam red-green-blue image centered on the example galaxy (blue: F150W, 1.5 μm; green: F277W, 2.8 μm; red: F444W, 4.4 μm). The image scale and corresponding physical size at z = 7.8328 is marked. b, Full NIRSpec prism spectrum covering 0.7 μm to 5.2 μm (cyan) and associated 1σ error spectrum (gray). c, Detail of the spectral region covering the nebular emission lines from the [O III] λλ4960, 5008 doublet and Hβ. The local best-fit line and continuum model is shown by the black curve. Credit: Nature Astronomy (2023). DOI: 10.1038/s41550-023-02078-7
James Webb peers deeper
The very first galaxies should therefore be "unpolluted" by heavy elements. But until recently we haven't been able to look so far back in time. In addition to being far away, the reason is that the longer light travels through space, the redder it becomes. For the most distant galaxies you have to look all the way into the infrared part of the spectrum, and only with the launch of James Webb did we have a telescope big and sensitive enough to see so far.
And the space telescope did not disappoint: Several has James Webb broken its own record for the most distant galaxy, and now it finally seems that we are reaching the epoch where some of the very first galaxies were created.
In a new study, published Sept. 21 in the journal Nature Astronomy, a team of astronomers from the Danish research center Cosmic Dawn Center at the Niels Bohr Institute and DTU Space in Copenhagen, has discovered what seems indeed to be some of the very first galaxies which are still in the process of being formed.
"Until recently it has been near-impossible to study how the first galaxies are formed in the early universe, since we simply haven't had the adequate instrumentation. This has now changed completely with the launch of James Webb," says Kasper Elm Heintz, leader of the study and assistant professor at the Cosmic Dawn Center.
This plot shows the observed galaxies in an "element-stellar mass diagram": The farther to the right a galaxy is, the more massive it is, and the farther up, the more heavy elements it contains. The gray icons represent galaxies in the present-day universe, while the red the new observations of early galaxies. These clearly have much less heavy elements than later galaxies, but agree roughly with theoretical predictions, indicated by the blue band. Credit: Kasper Elm Heintz, Peter Laursen. Credit: Nature Astronomy (2023). DOI: 10.1038/s41550-023-02078-7
Fundamental relation breaks down
The relationship between the total stellar mass of the galaxy and the amount of heavy elements is a bit more complex than that. How fast the galaxy produces new stars also has something to say. But if you correct for that, you get a beautiful, linear relationship: The more massive the galaxy, the more heavy elements.
But this relation is now being challenged by the latest observations.
"When we analyzed the light from 16 of these first galaxies, we saw that they had significantly less heavy elements, compared to what you'd expect from their stellar masses and the amount of new stars they produced," says Kasper Elm Heintz.
In fact the galaxies turned out to have, on average, four times less amounts of heavy elements that in the later universe. These results are in stark contrast to the current model where galaxies evolve in a form of equilibrium throughout most of the history of the universe.
Predicted by theories
The result is not entirely surprising though. Theoretical models of galaxy formation, based on detailed computer programs, do predict something similar. But now we've seen it.
The explanation, as proposed by the authors in the article, is simply that we are witnessing galaxies in the process of being created. Gravity has gathered the first clumps of gas, which have begun to form stars.
If the galaxies then lived their lives undisturbed, the stars would quickly enrich them with heavy elements. But in between the galaxies at that time were large amounts of fresh, unpolluted gas, streaming down to the galaxies faster than the stars can keep up.
"The result gives us the first insight into the earliest stages of galaxy formation which appear to be more intimately connected with the gas in between the galaxies than we thought.
"This is one of the first James Webb observations on this topic, so we're still waiting to see what the larger, more comprehensive observations that are currently being carried out can tell us.
"There is no doubt that we will shortly have a much clearer understanding of how galaxies and the first structures began their formation during the first billion years after the Big Bang," Kasper Elm Heintz concludes.
More information: Kasper E. Heintz et al, Dilution of chemical enrichment in galaxies 600 Myr after the Big Bang, Nature Astronomy (2023). DOI: 10.1038/s41550-023-02078-7
Research led by Jesse Reimink, assistant professor of geosciences at Penn State, suggests that the Earth's crust continued a slow process of reworking for billions of years, rather than rapidly slowing its growth some 3 billion years ago. The work contradicts existing theories that suggest the rapid formation of tectonic plates earlier in Earth's history, Reimink said. Credit: Pennsylvania State University
The Earth's crust continued a slow process of reworking for billions of years, rather than rapidly slowing its growth some 3 billion years ago, according to a Penn State-led research team. The new finding contradicts existing theories that suggest the rapid formation of tectonic plates earlier in Earth's history, researchers said.
The work may help answer a fundamental question about our planet and could hold clues as to the formation of other planets, according to lead author Jesse Reimink, assistant professor of geosciences.
"The dominating theory points to an inflection point some 3 billion years ago, implying we had a stagnant lid planet with no tectonic activity before a sudden shift to tectonic plates," Reimink said. "We've shown that's not the case."
To chart the formulation of the Earth's crust—or the crustal growth curve—researchers turned to more than 600,000 samples comprising the Earth's rock records database. Researchers across the globe—including at Penn State—have analyzed each rock sample in the record to determine geochemical contents and age. Researchers chose the rock records over mineral samples, which informed the theory of a more sudden formation, because they said the rock record is more sensitive and less prone to bias on those time scales.
Knowing that the reliability of the mineral record decreases through time, researchers recreated the crustal growth curve using the rock records. To do that, they developed a unique method for determining how igneous rocks dating to millions of years ago were reworked and reformed over time: experimentally demonstrating how the same rock could change in different ways over time.
Rocks can be reformed a number of ways, such as weathering into sediments or being remelted in the mantle, so researchers used this experimental data to inform novel mathematical tools capable of analyzing the rock records and working out the differences in sample changes.
"We calculated how much reworking has happened by looking at the composition of igneous rocks in a new way that teases out the proportion of sediments," Reimink said.
They used these calculations to calibrate the reworking documented in the rock records. Then, researchers calculated Earth's crustal growth curve using the new understanding of how the rocks were reformed. They compared the newly calculated curve to the rate of growth gleaned from mineral records by other experts.
Reimink and his team's work indicates the Earth's crust follows the path of the mantle—the layer on which the crust sits—suggesting a correlation between the two. It's not the first time geoscientists have suggested a more gradual crustal growth, Reimink said; however, it's the first time the rock record has been used to back it up.
"Our crustal growth curve matches the mantle record of growth, so it seems like those two signals are overlapping in a way that they did not when using the mineral record to create the crustal growth curve," Reimink said.
Reimink cautioned that the research improves on what researchers understand, but it's not the be-all and the end-all for crustal growth research. There are simply too few data points to speak to the vast time and space of the Earth's crust. However, Reimink said, further analyzing the existing data points may help inform investigations of other planets. Venus, for example, has no tectonic plates and could be a modern day example of early Earth.
"When did Earth and Venus become different?" Reimink asked. "And why did they become different? This crustal growth rate plays into that a lot. It tells the how, what and why of how planets evolved on different trajectories."
More information: J.R. Reimink et al, A whole-lithosphere view of continental growth, Geochemical Perspectives Letters (2023). DOI: 10.7185/geochemlet.2324
Artificial intelligence (AI) can help plant scientists collect and analyze unprecedented volumes of data, which would not be possible using conventional methods. Researchers at the University of Zurich (UZH) have now used big data, machine learning and field observations in the university's experimental garden to show how plants respond to changes in the environment.
Climate change is making it increasingly important to know how plants can survive and thrive in a changing environment. Conventional experiments in the lab have shown that plants accumulate pigments in response to environmental factors. To date, such measurements were made by taking samples, which required a part of the plant to be removed and thus damaged.
"This labor-intensive method isn't viable when thousands or millions of samples are needed. Moreover, taking repeated samples damages the plants, which in turn affects observations of how plants respond to environmental factors. There hasn't been a suitable method for the long-term observation of individual plants within an ecosystem," says Reiko Akiyama, first author of the study.
With the support of UZH's University Research Priority Program (URPP) "Evolution in Action," a team of researchers has now developed a method that enables scientists to observe plants in nature with great precision. PlantServation is a method that incorporates robust image-acquisition hardware and deep learning-based software to analyze field images, and it works in any kind of weather. The research has been published in Nature Communications.
Millions of images support evolutionary hypothesis of robustness
Using PlantServation, the researchers collected (top-view) images of Arabidopsis plants on the experimental plots of UZH's Irchel Campus across three field seasons (lasting five months from fall to spring) and then analyzed the more than four million images using machine learning.
The data recorded the species-specific accumulation of a plant pigment called "anthocyanin" as a response to seasonal and annual fluctuations in temperature, light intensity and precipitation.
PlantServation also enabled the scientists to experimentally replicate what happens after the natural speciation of a hybrid polyploid species. These species develop from a duplication of the entire genome of their ancestors, a common type of species diversification in plants. Many wild and cultivated plants such as wheat and coffee originated in this way.
In the current study, the anthocyanin content of the hybrid polyploid species A. kamchatica resembled that of its two ancestors: from fall to winter its anthocyanin content was similar to that of the ancestor species originating from a warm region, and from winter to spring it resembled the other species from a colder region.
"The results of the study thus confirm that these hybrid polyploids combine the environmental responses of their progenitors, which supports a long-standing hypothesis about the evolution of polyploids," says Rie Shimizu-Inatsugi, one of the study's two corresponding authors.
PlantServation was developed in the experimental garden at UZH's Irchel Campus.
"It was crucial for us to be able to use the garden on Irchel Campus to develop PlantServation's hardware and software, but its application goes even further: when combined with solar power, its hardware can be used even in remote sites," says Kentaro Shimizu, corresponding author and co-director of the URPP Evolution in Action.
"With its economical and robust hardware and open-source software, PlantServation paves the way for many more future biodiversity studies that use AI to investigate plants other than Arabidopsis—from crops such as wheat to wild plants that play a key role for the environment."
More information: Reiko Akiyama et al, Seasonal pigment fluctuation in diploid and polyploid Arabidopsis revealed by machine learning-based phenotyping method PlantServation, Nature Communications (2023). DOI: 10.1038/s41467-023-41260-3
