. Scientific Frontline: Earth Science
Showing posts with label Earth Science. Show all posts
Showing posts with label Earth Science. Show all posts

Friday, September 29, 2023

Ancient plant wax reveals how global warming affects methane in Arctic lakes

A 2014 field photo from Wax Lips Lake on northwest Greenland with the Greenland Ice Sheet in the background and three of the study authors (Jamie McFarlin, Everett Lasher, Yarrow Axford).
Photo Credit: Alex P. Taylor

By studying fossils from ancient aquatic plants, Northwestern University and University of Wyoming (UW) researchers are gaining a better understanding of how methane produced in Arctic lakes might affect — and be affected by — climate change.

In a new study, the researchers examined the waxy coatings of leaves preserved as organic molecules within sediment from the early-to-middle Holocene, a period of intense warming that occurred due to slow changes in Earth’s orbit 11,700 to 4,200 years ago. These wax biomarkers — which were once a part of common aquatic brown mosses — were preserved in sediment buried beneath four lakes in Greenland.

Monitoring changes in methane levels

By studying these biomarkers, the researchers discovered that past warming during the middle Holocene caused lakes across a wide range of Greenland’s climates to generate methane. Because methane is a more potent greenhouse gas than carbon dioxide, any changes in methane production with warming are important to understand.

Wednesday, September 27, 2023

Tree rings reveal a new kind of earthquake threat to the Pacific Northwest

Price Lake, in the eastern Olympic Mountains, formed when the Saddle Mountain fault impounded a stream and flooded the forest. Lead author Bryan Black and his team of divers collected the samples using an underwater hydraulic chainsaw.
Photo Credit: Bryan Black

In February, a 7.8-magnitude earthquake shook the Turkey-Syria border, followed by one nearly as large nine hours later. Shallow faults less than 18 miles beneath the surface buckled and ruptured, causing violent focused quakes that leveled thousands of buildings and killed tens of thousands.

Similar shallow faults ruptured about 1,000 years ago in the Puget Lowlands in western Washington, according to new University of Arizona-led research. Tree rings helped pinpoint that the seismic event occurred in late A.D. 923 or early 924. Their findings mean that a repeat event has the potential to again shake the region that is now home to over 4 million people, including Seattle, Tacoma and Olympia. The results were published in the journal Science Advances.

The ancient quake was either the result of all the shallow faults in the region rupturing together to produce an estimated 7.8-magnitude earthquake or – like in Turkey and Syria – twin quakes that occurred back-to-back with estimated magnitudes of 7.5 and 7.3, researchers found. Shallow faults typically result in more violent and focused shaking than earthquakes generated from other geological configurations.

Tuesday, September 26, 2023

From Seafloor to Space: New Bacterial Proteins Shine Light on Climate and Astrobiology

Methane clathrate (white, ice-like material) under a rock from the seafloor of the northern Gulf of Mexico. Deposits such as these demonstrate that methane and other gases cross the seafloor and enter the ocean.
Photo Credit: NOAA

Gigatons of greenhouse gas are trapped under the seafloor, and that’s a good thing. Around the coasts of the continents, where slopes sink down into the sea, tiny cages of ice trap methane gas, preventing it from escaping and bubbling up into the atmosphere.

While rarely in the news, these ice cage formations, known as methane clathrates, have garnered attention because of their potential to affect climate change. During offshore drilling, methane ice can get stuck in pipes, causing them to freeze and burst. The 2010 Deepwater Horizon oil spill is thought to have been caused by a buildup of methane clathrates.

But until now, the biological process behind how methane gas remains stable under the sea has been almost completely unknown. In a breakthrough study, a cross-disciplinary team of Georgia Tech researchers discovered a previously unknown class of bacterial proteins that play a crucial role in the formation and stability of methane clathrates.

New insect genus discovered in one of the most biodiverse rain forest regions in the world

Capitojoppa amazonica is a large parasitoid wasp species that has only been discovered in the Allpahuyao-Mishana National Reserve in the Peruvian Amazon.
Photo Credit: Kari Kaunisto, Biodiversity Unit of the University of Turku.

The Allpahuayo-Mishana National Reserve in Peru has often been described as the most biodiverse rainforest in the world. For example, in recent decades, scientists have discovered several new bird species from the region. The researchers of the University of Turku in Finland have studied the insect biodiversity in Allpahuayo-Mishana for over twenty years. In their latest study, the scientist described a new wasp genus, Capitojoppa, to science.

In their newly published study in the journal ZooKeys. The researchers describe a new wasp genus Capitojoppa to science, categorizing it to the subfamily Ichneumoninae. 

“Wasps belonging to this subfamily are usually large and colorful, especially in the tropics, and as larvae feed internally on moth and butterfly caterpillars and pupae. We have studied the biodiversity of ichneumonines in the Allpahuyao-Mishana National Reserve with the samples collected by the researchers of the University of Turku in Finland. In our studies, we have discovered several species unknown to science which we will describe in the future. The current study kicks off this research,” says Doctoral Candidate Brandon Claridge from the Utah State University in the United States.

Study shows birds that have evolved greater complexity are less biodiverse

Songbirds have less complex skeletons and are species rich
Photo Credit: cocoparisienne

A new study of the evolution of birds shows that as their skeletons become more complex, they also decrease in diversity, with fewer species as they become more specialized in their niches. The findings, published in Nature Communications, show a correlation between skeleton complexity and bird diversity for the first time, and help biologists better understand why biodiversity varies across the birds.

Researchers at the Milner Centre for Evolution at the University of Bath looked at 983 species across all major groups of living birds and measured the complexity of their skeletons by comparing the bones in their fore limbs (wings) and hind limbs (legs).

They found that less complex birds - those with a smaller difference between their fore and hind limbs - had more species diversity than those with higher complexity and a larger difference between their limbs.

For example, birds such as pigeons, gulls and songbirds (passerines) have low skeletal complexity but a high diversity of species living in varied habitats across the world.

Bladderwrack at risk of destruction as ocean acidity rises

Bladderwrack is one of the most common macroalgae growing along Sweden’s coasts. It is widespread up to the Bothnian Sea. In Europe, it grows all the way down to Portugal’s Atlantic coast.
Photo Credit: Alexandra Kinnby

Climate change is increasing carbon dioxide levels in the sea, causing bladderwrack seaweed to grow more quickly and to increase in size along the coast. However, a scientific study by researchers from the University of Gothenburg shows that this growth is illusory as, in more acidic seas, the seaweed will be unable to withstand storms and powerful waves.

Ocean acidification is a consequence of the oceans absorbing a large proportion of the carbon dioxide that is being released into the atmosphere. The drop in pH changes the conditions for the plants and animals that live in our seas. The ocean has already become more acidic and the worst-case scenario from the IPCC predicts an even further drop in pH, from 8.1 today down to around 7.7 by the end of this century.

“That might not sound very much, but pH is a logarithmic scale so it’s a big difference. We are already seeing calcifying species such as shellfish finding it more difficult to survive today,” says Alexandra Kinnby, a marine biologist at the University of Gothenburg.

Extreme heat likely to cause next mass extinction

Photo Credit: Juli Kosolapova

A new study shows unprecedented heat is likely to lead to the next mass extinction since the dinosaurs died out, eliminating nearly all mammals in some 250 million years time.

The research, published in Nature Geoscience presents the first-ever supercomputer climate models of the distant future and demonstrates how climate extremes will dramatically intensify when the world’s continents eventually merge to form one hot, dry and largely uninhabitable supercontinent.

The findings project how these high temperatures are set to further increase, as the sun becomes brighter, emitting more energy and warming the Earth. 

Tectonic processes, occurring in the Earth’s crust and resulting in supercontinent formation would also lead to more frequent volcanic eruptions, which produce huge releases of carbon dioxide into the atmosphere, further warming the planet. 

Mammals, including humans, have survived historically thanks to their ability to adjust to weather extremes, especially through adaptations such as fur and hibernating in the cold, as well as short spells of warm weather hibernation. 

Monday, September 25, 2023

Potentially hazardous La Niña weather more common, lasting longer

Wildfire in California.
Photo Credit: Ross Stone

The climate event La Niña that can cause devastating weather, impacting communities and industries from agriculture to tourism, is happening more frequently and lasting longer, according to new public impact research from the University of Hawaiʻi at Mānoa.

Atmospheric scientist Bin Wang from the School of Ocean and Earth Science and Technology (SOEST) found that five out of six La Niña events since 1998 have lasted more than one year, including an unprecedented triple-year event. The study was published in Nature Climate Change.

“The clustering of multiyear La Niña events is phenomenal given that only 10 such events have occurred since 1920,” said Wang, emeritus professor of atmospheric sciences in SOEST.

El Niño and La Niña, the warm and cool phases of a recurring climate pattern across the tropical Pacific, affect weather and ocean conditions, which can impact the public by influencing the marine environment and fishing industry in Hawaiʻi and throughout the Pacific Ocean. Long-lasting La Niñas could also cause persistent climate extremes.

Determining why so many multiyear La Niña events have emerged recently and whether they will become more common has sparked worldwide discussion among climate scientists, yet answers remain elusive.

Heat extremes in the soil are underestimated

Climate change intensifies extreme heat in the soil.
Photo Credit: André Künzelmann (UFZ)

For a long time, little attention was paid to soil temperatures. In contrast to air temperatures near the surface, hardly any reliable data was available because of the considerably more complex measurement. A research team leaded by the Helmholtz Centre for Environmental Research (UFZ) with participation of Leipzig University has now found not only that soil and air temperatures can differ but also that climate change has a much greater impact on the intensity and frequency of heat extremes in the soil than in the air. According to a study recently published in Nature Climate Change, this is particularly the case in Central Europe.

For the study, the research team coordinated by UFZ remote sensing scientist Dr Almudena García-García collected data from a wide range of sources: data from meteorological measuring stations, remote sensing satellites, the ERA5-Land data reanalysis set, and simulations of Earth system models. The researchers fed these data into the TX7d index, which is defined as the average of the daily maximum temperature in the hottest week of the year. It reflects the intensity of heat extremes (i.e. how high extreme temperatures can be). The researchers thus calculated the index for the 10-cm-thick upper soil layer and for the near-surface air at a height of up to 2 m for the years 1996 to 2021. At two thirds of the 118 meteorological measuring stations evaluated, the trend in heat extremes is stronger in the soil than in the air. “This means that heat extremes develop much faster in the soil than in the air”, García-García, lead author of the study. Based on the data available, this is especially true in Germany, Italy, and southern France. In terms of figures, according to station data, the intensity of heat extremes in Central Europe is increasing 0.7°C/decade faster in the soil than in the air.

Thursday, June 15, 2023

UD study evaluates how climate shocks impact the planted and harvested areas for crops

Dongyang Wei (left), a doctoral candidate in the Department of Geography and Spatial Sciences, and Kyle Davis, assistant professor in the Department of Geography and Spatial Sciences and the Department of Plant and Soil Sciences, as well as a resident faculty member with UD’s Data Science Institute, led a new study that focused on crop production shocks and how they are affected by variations in planted and harvested areas.
Photo Credit: Evan Krape

As the world faces more climate variability and extremes in the face of global warming, sudden environmental changes add an extra layer of stress to food production in the United States and around the world. It is critical, then, to figure out how the areas in which crops are planted and harvested respond to these stressors, which can bring on ‘shocks’ in production — or, put differently, sudden and statistically significant crop declines. 

These production shocks are a big concern in terms of food stability and many crops in the United States — such as corn, cotton, soybeans and wheat — are all experiencing more frequent production reductions as a result of these shocks.

A new study published in the scientific journal Nature Sustainability led by the University of Delaware’s Dongyang Wei looked at these production shocks and, specifically, how they are affected by variations in planted and harvested areas. 

Tropical butterflies’ wings could help them withstand climate change

Photo Credit: Courtesy of University of Cambridge

Tropical butterflies with bigger, longer and narrower wings are better able to stay cool when temperatures get too hot.

In fact, tropical species’ ability to keep cool at higher air temperatures mean they are more able to “thermoregulate” and keep a balanced body temperature compared to their evolutionary cousins in milder climates.  

Scientists say that the strategies of butterflies from Central America to stay cool mean they could actually be better equipped to deal with global warming than previously thought.

The team behind the latest study argue that conservation researchers should be careful not to assume creatures in hotter parts of the world will suffer most under rising temperatures – rather, some butterflies in temperate regions, such as Western and central Europe, could be at greater risk.

Equipped with hand-held nets, ecologists took the temperature of over 6,800 butterflies in Panama, Austria, the Czech Republic and the UK using a tiny thermometer-like probe. They compared the butterfly’s temperature to that of the surrounding air or the vegetation it was perched on.

Wednesday, June 14, 2023

Photosynthesis, Key to Life on Earth, Starts with a Single Photon

A cutting-edge experiment has revealed the quantum dynamics of one of nature’s most crucial processes
Illustration Credit: Jenny Nuss/Berkeley Lab

Using a complex cast of metal-studded pigments, proteins, enzymes, and co-enzymes, photosynthetic organisms can convert the energy in light into the chemical energy for life. And now, thanks to a study published today in Nature, we know that this organic chemical reaction is sensitive to the smallest quantity of light possible – a single photon.

The discovery solidifies our current understanding of photosynthesis and will help answer questions about how life works on the smallest of scales, where quantum physics and biology meet.

“A huge amount of work, theoretically and experimentally, has been done around the world trying to understand what happens after a photon is absorbed. But we realized that nobody was talking about the first step. That was still a question that needed to be answered in detail,” said co-lead author Graham Fleming, a senior faculty scientist in the Biosciences Area at Lawrence Berkeley National Laboratory (Berkeley Lab) and professor of chemistry at UC Berkeley.

In their study, Fleming, co-lead author Birgitta Whaley, a senior faculty scientist in the Energy Sciences Area at Berkeley Lab, and their research groups showed that a single photon can indeed initiate the first step of photosynthesis in photosynthetic purple bacteria. Because all photosynthetic organisms use similar processes and share an evolutionary ancestor, the team is confident that photosynthesis in plants and algae works the same way. “Nature invented a very clever trick,” Fleming said.

Plate tectonics not required for the emergence of life

Plate tectonics involves the horizontal movement and interaction of large plates on Earth’s surface. New research indicates that mobile plate tectonics—thought to be necessary for the creation of a habitable planet—was not occurring on Earth 3.9 billion years ago.
Illustration Credit: Michael Osadciw / University of Rochester

The finding contradicts previous assumptions about the role of mobile plate tectonics in the development of life on Earth.

Scientists have taken a journey back in time to unlock the mysteries of Earth’s early history, using tiny mineral crystals called zircons to study plate tectonics billions of years ago. The research sheds light on the conditions that existed in early Earth, revealing a complex interplay between Earth’s crust, core, and the emergence of life.

Plate tectonics allows heat from Earth’s interior to escape to the surface, forming continents and other geological features necessary for life to emerge. Accordingly, “there has been the assumption that plate tectonics is necessary for life,” says John Tarduno, who teaches in the Department of Earth and Environmental Sciences at the University of Rochester. But new research casts doubt on that assumption.

New Clues About Origin of Complex Life Trace Roots to Common Ancestor

According to this latest study, all complex life forms (a.k.a. eukaryotes) trace their roots back to a common ancestor among a group of microbes called the Asgard archaea.
Illustration Credit: The University of Texas at Austin.

Thor, the legendary Norse god from the mythological city of Asgard, is not alone. According to groundbreaking research published in the journal Nature, we humans — along with eagles, starfish, daisies and every complex organism on Earth — are, in a sense, Asgardians.

Analyzing the genomes of hundreds of different microbes called archaea, researchers at The University of Texas at Austin and other institutions have discovered that eukaryotes — complex life forms with nuclei in their cells, including all the world’s plants, animals, insects and fungi — trace their roots to a common Asgard archaean ancestor. That means eukaryotes are, in the parlance of evolutionary biologists, a “well-nested clade” within Asgard archaea, similar to how birds are one of several groups within a larger group called dinosaurs, sharing a common ancestor. The team has found that all eukaryotes share a common ancestor among the Asgards.

No fossils of eukaryotes have been found from farther back than about 2 billion years ago, suggesting that before that, only various types of microbes existed.

“So, what events led microbes to evolve into eukaryotes?” said Brett Baker, UT Austin associate professor of integrative biology and marine science. “That’s a big question. Having this common ancestor is a big step in understanding that.”

Tuesday, June 13, 2023

Pass the salt: This space rock holds clues as to how Earth got its water

Asteroid Itokawa as seen by the Hayabusa spacecraft. The peanut-shaped S-type asteroid measures approximately 1,100 feet in diameter and completes one rotation every 12 hours.
Photo Credit: JAXA

The discovery of tiny salt grains in an asteroid sample brought to Earth by the Japanese Hayabusa spacecraft provides strong evidence that liquid water may be more common in the solar system's largest asteroid population than previously thought.

Sodium chloride, better known as table salt, isn't exactly the type of mineral that captures the imagination of scientists. However, a smattering of tiny salt crystals discovered in a sample from an asteroid has researchers at the University of Arizona Lunar and Planetary Laboratory excited, because these crystals can only have formed in the presence of liquid water.

Even more intriguing, according to the research team, is the fact that the sample comes from an S-type asteroid, a category known to mostly lack hydrated, or water-bearing, minerals. The discovery strongly suggests that a large number of asteroids hurtling through the solar system may not be as dry as previously thought. The finding, published in Nature Astronomy, gives renewed push to the hypothesis that most, if not all, water on Earth may have arrived by way of asteroids during the planet's tumultuous infancy.

Zega and lead study author Shaofan Che, a postdoctoral fellow at the Lunar and Planetary Laboratory, performed a detailed analysis of samples collected from asteroid Itokawa in 2005 by the Japanese Hayabusa mission and brought to Earth in 2010. 

Vaccine against deadly chytrid fungus primes frog microbiome for future exposure

A new study led by researchers at Penn State found that a new vaccine against the deadly chytrid fungus in frogs can shift the composition of the microbiome, making frogs more resilient to future exposure to the fungus.
Photo Credit: Paul Bonnar

A human's or animal’s microbiome — the collection of often beneficial microorganisms, including bacteria and fungi, that live on or within a host organism — can play an important role in the host’s overall immune response, but it is unclear how vaccines against harmful pathogens impact the microbiome. A new study led by researchers at Penn State found that a new vaccine against the deadly chytrid fungus in frogs can shift the composition of the microbiome, making frogs more resilient to future exposure to the fungus. The study, published June 12 in a special issue of the journal Philosophical Transactions of the Royal Society B, suggests that the microbiome response could be an important, overlooked part of vaccine efficacy.

“The microorganisms that make up an animal’s microbiome can often help defend against pathogens, for example by producing beneficial metabolites or by competing against the pathogens for space or nutrients,” said Gui Becker, associate professor of biology at Penn State and leader of the research team. “But what happens to your microbiome when you get a vaccine, like a COVID vaccine, flu shot, or a live-attenuated vaccine like the yellow fever vaccine? In this study, we used frogs as a model system to start exploring this question.”

Frogs and other amphibians are threatened by the chytrid fungus, which has led to extinctions of some species and severe population declines in hundreds of others across several continents. In susceptible species, the fungus causes a sometimes-lethal skin disease.

Summit study fathoms troubled waters of ocean turbulence

Simulations performed on Oak Ridge National Laboratory’s Summit supercomputer generated one of the most detailed portraits to date of how turbulence disperses heat through ocean water under realistic conditions.
Image Credit: Miles Couchman

Simulations performed on the Summit supercomputer at the Department of Energy’s Oak Ridge National Laboratory revealed new insights into the role of turbulence in mixing fluids and could open new possibilities for projecting climate change and studying fluid dynamics.

The study, published in the Journal of Turbulence, used Summit to model the dynamics of a roughly 10-meter section of ocean. That study generated one of the most detailed simulations to date of how turbulence disperses heat through seawater under realistic conditions. The lessons learned can apply to other substances, such as pollution spreading through water or air.

“We’ve never been able to do this type of analysis before, partly because we couldn’t get samples at the necessary size,” said Miles Couchman, co-author and a postdoc at the University of Cambridge. “We needed a machine-like Summit that could allow us to observe these details across the vast range of relevant scales.”

Monday, June 12, 2023

CRISPR/Cas9-Based Gene Drive Could Suppress Agricultural Pests

NC State researchers used a florescent protein to mark the genetic changes to spotted-wing Drosophila.
Photo Credit: Courtesy of the researchers / North Carolina State University

Researchers have developed a “homing gene drive system” based on CRISPR/Cas9 that could be used to suppress populations of Drosophila suzukii vinegar flies – so-called “spotted-wing Drosophila” that devastate soft-skinned fruit in North America, Europe and parts of South America – according to new research from North Carolina State University.

The NC State researchers developed dual CRISPR gene drive systems that targeted a specific D. suzukii gene called doublesex, which is important for sexual development in the flies. CRISPR stands for “clustered regularly interspaced short palindromic repeats” and Cas9 is an enzyme that performs like molecular scissors to cut DNA. CRISPR systems are derived from bacterial immune systems that recognize and destroy viruses and other invaders, and are being developed as solutions to problems in human, plant and animal health, among other uses.

Targeting the doublesex gene resulted in female sterility in numerous experiments as females were unable to lay eggs, says Max Scott, an NC State entomologist who is the corresponding author of a paper in Proceedings of the National Academy of Sciences that describes the research.

“This is the first so-called homing gene drive in an agricultural pest that potentially could be used for suppression,” Scott said.

Which came first: the reptile or the egg?

Photo Credit: PIRO

The earliest reptiles, birds and mammals may have been born live young, researchers from Nanjing University and University of Bristol have revealed.

Until now, the hard-shelled egg was thought to be the key to the success of the amniotes - a group of vertebrates that undergo embryonic or fetal development within an amnion, a protective membrane inside the egg.

However, a fresh study of 51 fossil species and 29 living species which could be categorized as oviparous (laying hard or soft-shelled eggs) or viviparous (giving birth to live young) suggests otherwise.

The findings, published today in Nature Ecology & Evolution, show that all the great evolutionary branches of Amniota, namely Mammalia, Lepidosauria (lizards and relatives), and Archosauria (dinosaurs, crocodilians, birds) reveal viviparity and extended embryo retention in their ancestors.

Extended embryo retention (EER) is when the young are retained by the mother for a varying amount of time, likely depending on when conditions are best for survival.

Climate Change: Rising Rainfall, not Temperatures, Threaten Giraffe Survival

Masai giraffes in Tanzania have lower survival during seasons of heavier rainfall, which is predicted to increase under climate change.
Photo Credit: Mariola Grobelska

Giraffes in the East African savannahs are adapting surprisingly well to the rising temperatures caused by climate change. However, they are threatened by increasingly heavy rainfall, as researchers from the University of Zurich and Pennsylvania State University show.

Climate change is expected to cause widespread declines in wildlife populations worldwide. Yet, little was previously known about the combined climate and human effects on the survival rates not only of giraffes, but of any large African herbivore species. Now researchers from the University of Zurich and Pennsylvania State University have concluded a decade-long study – the largest to date – of a giraffe population in the Tarangire region of Tanzania. The study area spanned more than a thousand square kilometers, including areas inside and outside protected areas. Contrary to expectations, higher temperatures were found to positively affect adult giraffe survival, while rainier wet seasons negatively impacted adult and calf survival.

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Heat extremes in the soil are underestimated

Climate change intensifies extreme heat in the soil. Photo Credit: André Künzelmann (UFZ) For a long time, little attention was paid to soil...

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