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

Monday, February 10, 2025

Anomaly in the Deep Sea: Extraordinary Accumulation of Rare Atoms Could Improve Geological Dating Methods

Schematic depiction of production and incorporation of cosmogenic 10Be into ferromanganese crusts. A pronounced anomaly in 10Be concentration about 10 million years ago was discovered. This anomaly has great potential as time marker for the Late Miocene.
Image Credit: © HZDR / blrck.de

Beryllium-10, a rare radioactive isotope produced by cosmic rays in the atmosphere, provides valuable insights into the Earth's geological history. A research team from the Helmholtz-Zentrum Dresden-Rossendorf (HZDR), in collaboration with the TUD Dresden University of Technology and the Australian National University (ANU), has discovered an unexpected accumulation of this isotope in samples taken from the Pacific seabed. Such an anomaly may be attributed to shifts in ocean currents or astrophysical events that occurred approximately 10 million years ago. The findings hold the potential to serve as a global time marker, representing a promising advancement in the dating of geological archives spanning millions of years. The team presents its results in the scientific journal Nature Communications.

Radionuclides are types of atomic nuclei (isotopes) that decay into other elements over time. They are used to date archaeological and geological samples, with radiocarbon dating being one of the most well-known methods. In principle, radiocarbon dating is based on the fact that living organisms continuously absorb the radioactive isotope carbon-14 (14C) during their lifetime. Once an organism dies, the absorption ceases, and the 14C content starts to decrease through radioactive decay with a half-life of approximately 5,700 years. By comparing the ratio of unstable 14C to stable carbon-12 (12C), researchers can determine the date of the organism's death.

Tuesday, February 4, 2025

Cracks in Greenland Ice Sheet are growing, study finds

Crevasses at Store Glacier, a marine-terminating outlet glacier of the western Greenland Ice Sheet.
 Photo Credit: Tom Chudley (Durham University)

A new study published this week in Nature Geoscience reveals that in response to climate change, the Greenland Ice Sheet is developing significantly more surface crevasses in key regions – a change that may accelerate ice loss and contribute to rising sea levels.

The research was led by Thomas Chudley, a research assistant professor at Durham University and former research associate at The Ohio State University’s Byrd Polar and Climate Research Center. The study analyzed high-resolution 3D surface maps and found that crevasses – wedge-shaped fractures in ice – had significantly increased in size and depth at the ice sheet’s fast-flowing edges over the entire Greenland Ice Sheet between 2016 and 2021.

Scientists Discovered the Oldest Junipers in the Arctic

Dendrochronologists determined the age of the trees by cross-dating. The photo shows a sample of juniper.
Photo Credit: Rashit Khantemirov

A group of dendrochronologists from Italy, Denmark, Germany and Russia has discovered the longest-lived woody plant in the Arctic. It was the common juniper (Juniperus communis). The oldest juniper bush, which was found in the north of Finland, is 1647 years old. In the Polar Urals, the oldest juniper bush lived half as long, yet it is the longest-living organism in the Urals. Scientists told about the long-lived junipers in an article in the journal Ecology.

"Many species in the genus Juniperus are long-lived woody plants. But there was a lack of reliable data on the most common species, the common juniper. There are legends about junipers that are two thousand years old, but there was no reliable evidence. Counting the number of annual rings, rather than estimating the age by trunk thickness, shrub size and other indirect signs, can be considered reliable evidence," explains Rashit Khantemirov, co-author of the paper, a member of the Laboratory of Natural Science Methods in Humanities at Ural Federal University and the Laboratory of Dendrochronology and IER&J of the Ural Branch of the Russian Academy of Sciences.

Monday, February 3, 2025

Plant Power: A New Method to Model How Plants Move Water Globally

Golden hour looking out on the UConn Forest.
Photo Credit: Sean Flynn/UConn Photo

Earth systems models are an important tool for studying complex processes occurring around the planet, such as those in and between the atmosphere and biosphere, and they help researchers and policymakers better understand phenomena like climate change. Incorporating more data into these simulations can improve modeling accuracy; however, sometimes, this requires the arduous task of gathering millions of data points.

Researchers, including UConn Department of Natural Resources and the Environment Assistant Professor James Knighton, Pablo Sanchez-Martinez from the University of Edinburgh, and Leander Anderegg from the University of California Santa Barbara, have developed a method to bypass the need for gathering data for over 55,000 tree species to better account for how plants influence the flow of water around the planet. Their findings are published in Nature Scientific Data.

Plants play essential roles in Earth’s processes, from capturing carbon and making oxygen available for other life forms like humans. Plants are also responsible for the movement of water, says Knighton, where an estimated 60% of all rain is returned to the atmosphere through transpiration. This huge global-scale movement of water through plants is complex and currently represented by Earth system models (ESMs) in a simplified way says Knighton, where all plants in a region may be considered as a single entity (i.e., a plant functional type),

Temperature, rainfall and tides speed glacier flow on a daily basis

The calving front of the Bowdoin Glacier/Kangerluarsuup Sermia.
Photo Credit: Shin Sugiyama

Even though ‘glacial’ is commonly used to describe extremely slow, steady movement, a new study has found that glaciers speed up and slow down on a daily – even hourly – basis in response to changes in air temperature, rainfall and the tides.

A research team including scientists from Japan’s Hokkaido University studied the movement of a glacier in Greenland over six summers and mapped those movements against local weather patterns and tides to explore how these affect the glacier’s flow. The results have been published in the journal The Cryosphere.

“Short-term speed variations are key to understanding the physical processes controlling glacial motion, but studies are sparse for Greenlandic tidewater glaciers, particularly near the calving front,” says Hokkaido University’s Shin Sugiyama, lead author of the study. “Studying glacier dynamics near the ocean boundary is crucial to understanding the current and future mass loss of the ice sheet.”

Thursday, January 30, 2025

Ancient Antarctic ice loss offers insights into future climate scenarios

Photo Credit: University of Cambridge / British Antarctic Survey.

Scientists from the University of Cambridge and British Antarctic Survey have used ice core records to draw new conclusions about how Antarctica was affected by increased global temperatures over 100,000 years ago. The new paper, published today in the journal Nature, shows that large parts of the West Antarctic Ice Sheet were lost, contributing to significant sea level rise. However, the data also suggests that the nearby Ronne Ice Shelf – which climate models project could be lost under future warming scenarios – survived this period of global heating.

Greenhouse gas emissions are warming the Earth at an unprecedented speed and scale. While anthropogenic warming has no direct historical parallel, warm episodes in Earth’s history can offer clues to the future.

A team of ice core scientists, led by Eric Wolff from Cambridge University, wanted to find out what happened to the West Antarctic Ice Sheet during the Last Interglacial, when the polar regions were about 3°C warmer than present and sea levels were significantly higher. This period of Earth’s history is considered comparable to conditions we might see within decades.

Sunday, January 12, 2025

New data on atmosphere from Earth to the edge of space

Clouds in Antarctica.
Our weather is influenced by many factors, at ground level (such as mountains and human activity), interactions in our atmosphere, and space (such as auroras and magnetic fields).
Photo Credit: © Kaoru Sato

A team led by researchers at the University of Tokyo have created a dataset of the whole atmosphere, enabling new research to be conducted on previously difficult-to-study regions. Using a new data-assimilation system called JAGUAR-DAS, which combines numerical modeling with observational data, the team created a nearly 20-yearlong set of data spanning multiple levels of the atmosphere from ground level up to the lower edges of space. Being able to study the interactions of these layers vertically and around the globe could improve climate modeling and seasonal weather forecasting. There is also potential for interdisciplinary research between atmospheric scientists and space scientists, to investigate the interplay between space and our atmosphere and how it affects us on Earth.

Complaining about the weather, and about weather forecasters when they get things wrong, is a popular pastime for many. But a meteorologist’s job is not easy. Our atmosphere is multilayered, interconnected and complex, and global climate change is making it even harder to forecast both long-term and sudden, extreme weather events.

Monday, January 6, 2025

Increased wildfire activity may be a feature of past periods of abrupt climate change, study finds


A new study investigating ancient methane trapped in Antarctic ice suggests that global increases in wildfire activity likely occurred during periods of abrupt climate change throughout the last Ice Age.

The study, just published in the journal Nature, reveals increased wildfire activity as a potential feature of these periods of abrupt climate change, which also saw significant shifts in tropical rainfall patterns and temperature fluctuations around the world.

“This study showed that the planet experienced these short, sudden episodes of burning, and they happened at the same time as these other big climate shifts,” said Edward Brook, a paleoclimatologist at Oregon State University and a co-author of the study. “This is something new in our data on past climate.”

The findings have implications for understanding modern abrupt climate change, said the study’s lead author, Ben Riddell-Young, who conducted the research as part of his doctoral studies in OSU’s College of Earth, Ocean, and Atmospheric Sciences.

“This research shows that we may not be properly considering how wildfire activity might change as the climate warms and rainfall patterns shift,” said Riddell-Young, who is now a postdoctoral scholar at the Cooperative Institute for Research in Environmental Sciences at the University of Colorado, Boulder.

Monday, April 1, 2024

Atmospheric Scientists Link Arctic Sea Loss Ice to Strong El Niño Events


El Niño, a climate pattern where warm waters in the eastern Pacific fuel hotter weather, is finally beginning to wane after bringing a long stretch of record heat and heavy precipitation across the world since last summer. 

A new study, published in Science Advances by researchers at the University at Albany and Nanjing University of Information Science and Technology in China, has found that these events, which typically occur once every few years, might become even stronger due to melting Arctic sea ice.

Using a combination of climate model simulations and observational data, the researchers found that the current interaction of Arctic sea ice with the atmosphere reduces the strength of El Niño events by up to 17 percent, compared to when the interaction is removed.

The amount of sea ice that survives the Arctic summer has declined 12.2 percent per decade since the late 1970s and projections show the region could experience its first ice-free summer by 2040. 

“Climate models are already projecting a strengthened El Niño in the upcoming decades due to global warming. Arctic sea ice is also projected to decline rapidly in the upcoming decades, said Aiguo Dai, a Distinguished Professor in the Department of Atmospheric and Environmental Sciences and study co-author. 

Friday, March 29, 2024

‘Back to the Future’ to Forecast the Fate of a Dead Florida Coral Reef

Alex Modys, Ph.D., diving at the coral death assemblage in Pompano Ridge and digging up a subfossil coral, Orbicella annularis.
Photo Credit: Anton Olenik, Ph.D., Florida Atlantic University

Rising temperatures and disease outbreaks are decimating coral reefs throughout the tropics. Evidence suggests that higher latitude marine environments may provide crucial refuges for many at-risk, temperature-sensitive coral species. However, how coral populations expand into new areas and sustain themselves over time is constrained by the limited scope of modern observations. 

What can thousands of years of history tell us about what lies ahead for coral reef communities? A lot. In a new study, Florida Atlantic University researchers and collaborators provide geological insights into coral range expansions by reconstructing the composition of a Late Holocene-aged subfossil coral death assemblage in an unusual location in Southeast Florida and comparing it to modern reefs throughout the region. 

Located off one of the most densely populated and urbanized coastlines in the continental United States, the Late Holocene coral death assemblage known as “Pompano Ridge,” records a northward range expansion of tropical coral communities that occurred during a period of regional climate warming more than 2,000 years ago.

Could this happen again in the face of climate change? Going “back to the future,” this study offers a unique glimpse into what was once a vibrant coral reef assemblage and explores if history can repeat itself.

Largest ice shelf in Antarctica lurches forward once or twice each day

A side view of the Ross Ice Shelf, the largest ice shelf in Antarctica. Washington University in St. Louis seismologist Doug Wiens discovered that unexpected movements of the Ross Ice Shelf are triggered by the sudden slipping of parts of the Willans Ice Stream.
Photo Credit: Lin Padgham
(CC BY 2.0.)

In Antarctica, heavy glaciers are always on the move. Conveyor belts of ice known as ice streams are the corridors of faster flow that carry most of the vast glaciers’ ice and sediment debris out toward the ocean.

One such ice stream jostles the entire Ross Ice Shelf out of place at least once daily, according to new research from Washington University in St. Louis.

This finding is significant because of the scale of the Ross Ice Shelf: It is the largest ice shelf in Antarctica, about the same size as the country of France.

“We found that the whole shelf suddenly moves about 6 to 8 centimeters (or 3 inches) once or twice a day, triggered by a slip on an ice stream that flows into the ice shelf,” said Doug Wiens, the Robert S. Brookings Distinguished Professor of earth, environmental and planetary science​s in Arts & Sciences. “These sudden movements could potentially play a role in triggering icequakes and fractures in the ice shelf.”

The Ross Ice Shelf is a floating lip of ice that extends out over the ocean from inland glaciers.

Thursday, March 28, 2024

Key Ocean Current Contains a Warning on Climate

Scientists extracted a 5.3 million-year record of the Antarctic Circumpolar Current by drilling sediment cores in the Earth’s most remote waters. Here, the drill ship JOIDES Resolution makes its way through the far southeast Pacific.
Photo Credit: Gisela Winckler

It carries more than 100 times as much water as all the world’s rivers combined. It reaches from the ocean’s surface to its bottom, and measures as much as 2,000 kilometers across. It connects the Indian, Atlantic and Pacific oceans, and plays a key role in regulating global climate. Continuously swirling around the southernmost continent, the Antarctic Circumpolar Current is by far the world’s most powerful and consequential mover of water. In recent decades it has been speeding up, but scientists have been unsure whether that is connected to human-induced global warming, and whether the current might offset or amplify some of warming’s effects.

In a new study, an international research team used sediment cores from the planet’s roughest and most remote waters to chart the ACC’s relationship to climate over the last 5.3 million years. Their key discovery: During past natural climate swings, the current has moved in tandem with Earth’s temperature, slowing down during cold times and gaining speed in warm ones―speedups that abetted major losses of Antarctica’s ice. This suggests that today’s speedup will continue as human-induced warming proceeds. That could hasten the wasting of Antarctica’s ice, increase sea levels, and possibly affect the ocean’s ability to absorb carbon from the atmosphere.

“This is the mightiest and fastest current on the planet. It is arguably the most important current of the Earth climate system,” said study coauthor Gisela Winckler, a geochemist at Columbia University’s Lamont-Doherty Earth Observatory who co-led the sediment sampling expedition. The study “implies that the retreat or collapse of Antarctic ice is mechanistically linked to enhanced ACC flow, a scenario we are observing today under global warming,” she said.

Wednesday, March 20, 2024

Natural recycling at the origin of life

Volcanic freshwater lakes, similar to those found in Iceland today, offered a favorable niche on an early earth. The low-salt, alkaline conditions enabled early RNA replication.
Photo Credit: © Dieter Braun

How was complex life able to develop on the inhospitable early Earth? At the beginning there must have been ribonucleic acid (RNA) to carry the first genetic information. To build up complexity in their sequences, these biomolecules need to release water. On the early Earth, which was largely covered in seawater, that was not so easy to do. In a paper recently published in the Journal of the American Chemical Society (JACS), researchers from the team of LMU professor Dieter Braun have shown that in RNA’s struggle with the surrounding water, its natural recycling capabilities and the right ambient conditions could have been decisive.

“The building blocks of RNA release a water molecule for every bond they form in a growing RNA chain,” explains Braun, spokesperson for the Collaborative Research Centre (CRC) Molecular Evolution in Prebiotic Environments and coordinator at the ORIGINS Excellence Cluster. “When, conversely, water is added to an RNA molecule, the RNA building blocks are fed back into the prebiotic pool.” This turnover of water works particularly well under low saline conditions with high pH levels. “Our experiments indicate that life could emerge from a very small set of molecules, under conditions such as those prevailing on volcanic islands on the early Earth,” says Adriana Serrão, lead author of the study.

Oxford researchers uncover remarkable archive of ancient human brains

Fragments of brain from an individual buried in a Victorian workhouse cemetery (Bristol, UK), some 200 years ago. No other soft tissue survived amongst the bones, which were dredged from the heavily waterlogged grave.
Photo Credit: Alexandra L. Morton-Hayward.

A new study conducted by researchers at the University of Oxford has challenged previously held views that brain preservation in the archaeological record is extremely rare. The team carried out the largest study to date of the global archaeological literature about preserved human brains to compile an archive that exceeds 20-fold the number of brains previously compiled. The findings have been published today in the Proceedings of the Royal Society B.

Soft tissue preservation in the geological record is relatively rare, and, except where deliberate intervention halts the process of decay (for instance, during embalming or freezing), the survival of entire organs is particularly unusual. The spontaneous preservation of the brain in the absence of any other soft tissues - that is, the brain’s survival amongst otherwise skeletonized remains - has historically been regarded as a ‘one-of-a kind’ phenomenon. This new research reveals, however, that nervous tissues actually persist in much greater abundances than traditionally thought, assisted by conditions that prevent decay.

Monday, March 11, 2024

Unprecedented heatwaves revealed by marine lab’s historic data

Photo Credit: Courtesy of University of Auckland

A unique record at the University of Auckland's Leigh marine lab shows dramatic change in the Hauraki Gulf.

A thermometer dipped in a bucket of sea water on New Year’s Day in 1967 began a unique record which shows the dramatic intensification of warming in the Hauraki Gulf.

Sea-surface readings at the Leigh Marine Laboratory north of Auckland since that time indicate the “unprecedented nature of recent marine heatwaves,” according to Dr Nick Shears of the University of Auckland, Waipapa Taumata Rau.

The number of marine heatwave days and their cumulative intensity has increased sharply since 2012, Shears and his co-authors write in a paper published in the New Zealand Journal of Marine and Freshwater Research.

In past decades, some years had no heatwaves, but that hasn’t happened since 2012. Sponges `melting,’ becoming detached from rocks and dying, along with seaweed and kelp die-offs, are among temperature effects.

Especially warm autumns and winters have likely facilitated an increase in subtropical and tropical species such as the long-spined sea urchin Centrostephanus rodgersii, a voracious herbivore which can lay waste to deep reef environments.

Tuesday, March 5, 2024

Researchers provide unprecedented view into aerosol formation in Earth’s lower atmosphere

Researchers identified evidence of Criegee intermediate oligomerization in the Amazon rainforest.
 Image Credit: Argonne National Laboratory
Eighty-five percent of the Earth’s air resides in the lowest layer of its atmosphere, or troposphere. Yet, major gaps remain in our understanding of the atmospheric chemistry that drives changes in the troposphere’s composition.

One especially important gap in knowledge is the formation and prevalence of secondary organic aerosols (SOAs), which impact the planet’s radiation balance, air quality and human health. But that gap is closing — due to the groundbreaking discoveries of an international team of researchers led by the U.S. Department of Energy’s (DOE) Argonne National Laboratory, Sandia National Laboratories and NASA’s Jet Propulsion Laboratory (JPL).

The scientists detail their findings in a new paper published in Nature Geosciences

The team focused on a class of compounds known as Criegee intermediates (CIs). Researchers suspect that CIs play a critical role in the formation of SOAs when they combine via a process called oligomerization. But no one had ever directly identified the chemical signatures of this process in the field — until now.

Can ‘Super Volcanoes’ Cool the Earth in a Major Way? A New Study Suggests No.

Quizapu Volcano, Chile
Photo Credit: Kevin Krajick / Earth Institute

Some 74,000 years ago, the Toba volcano in Indonesia exploded with a force 1,000 times more powerful than the 1980 eruption of Mount St. Helens. The mystery is what happened after that.

When it comes to the most powerful volcanoes, researchers have long speculated how post-eruption global cooling—sometimes called volcanic winter—could potentially pose a threat to humanity after a so-called super eruption. Previous studies have agreed that some planet-wide cooling would occur, but they have diverged on how much. Estimates have ranged from 3.6 to 14 degrees F (2 to 8 degrees C).

In a new study published in the Journal of Climate, a team from NASA’s Goddard Institute for Space Studies, an affiliate of the Columbia Climate School, used advanced computer modeling to simulate super eruptions like the Toba event. They found that post-eruption cooling would probably not exceed 2.7 degrees F (1.5 C) for even the most powerful blasts.

“The relatively modest temperature changes we found most compatible with the evidence could explain why no single super eruption has produced firm evidence of global-scale catastrophe for humans or ecosystems,” said lead author Zachary McGraw, a postdoctoral researcher at Goddard and Columbia.

To qualify as a super eruption, a volcano must release more than 240 cubic miles (1,000 cubic kilometers) of magma. These eruptions are extremely powerful, and rare. The most recent super eruption occurred more than 22,000 years ago in New Zealand. The best-known example may be the eruption that blasted Yellowstone Crater in Wyoming about 2 million years ago.

How Does a River Breathe?

Scientists at Pacific Northwest National Laboratory have been studying processes that affect how rivers and streams breathe, particularly in the Columbia River Basin, to help prepare for future changes related to water quality and climate change. 
Photo Credit: Andrea Starr | Pacific Northwest National Laboratory

Take a deep breath.

Pay attention to how air moves from your nose to your throat before filling your lungs with oxygen.

As you exhale your breath, a mix of oxygen and carbon dioxide leaves your nose and mouth.

Did you know that streams and rivers “breathe” in a similar way?

The United States is home to more than 250,000 of these flowing bodies of water that connect to coastal zones and oceans. They vary in size, from small streams to large rivers, but all take in oxygen and give off carbon dioxide and other greenhouse gases like methane. 

Over recent years, a team of scientists led by Pacific Northwest National Laboratory (PNNL) has been immersed in crucial research around the processes and interactions that contribute to greenhouse gas dynamics. Their work focuses on whole networks of streams and rivers, as well as the land surrounding these systems.       

Their work also includes factors that can disturb how streams and rivers breathe. Some of these disturbances happen beyond streams, like wildfires, but still impact how streams breathe by changing how material enters streams. Understanding these impacts is key to addressing challenges related to water quality, global carbon cycling, and climate change.

Monday, March 4, 2024

Producing Hydrogen from Rocks Gains Steam as Scientists Advance New Methods

Researchers are studying chemical catalysts that can produce hydrogen gas from iron-rich rocks.
Photo Credit: Toti Larson / UT Austin.

In a project that could be a game changer for the energy transition, researchers at The University of Texas at Austin are exploring a suite of natural catalysts to help produce hydrogen gas from iron-rich rocks without emitting carbon dioxide.

If the scientists are successful, the project could jump-start a brand-new type of hydrogen industry: geologic hydrogen.

“We’re producing hydrogen from rocks,” said Toti Larson, a research associate professor at the UT Jackson School of Geosciences Bureau of Economic Geology and the lead researcher on the project. “It’s a type of non-fossil fuel production of hydrogen from iron-rich rocks that has never been attempted at an industrial scale.”

The research team recently received a $1.7 million grant from the Department of Energy and is collaborating with scientists at the University of Wyoming’s School of Energy Resources to explore the feasibility of this process on different rock types across the United States.

Wednesday, February 28, 2024

80 mph speed record for glacier fracture helps reveal the physics of ice sheet collapse

In this illustration, seawater flows deep below the surface into an actively opening ice shelf rift in Antarctica. New research shows that such rifts can open very quickly, and that the seawater rushing in helps control the speed of ice shelf breakage.
Illustration Credit: Rob Soto

There’s enough water frozen in Greenland and Antarctic glaciers that if they melted, global seas would rise by many feet. What will happen to these glaciers over the coming decades is the biggest unknown in the future of rising seas, partly because glacier fracture physics is not yet fully understood.

A critical question is how warmer oceans might cause glaciers to break apart more quickly. University of Washington researchers have demonstrated the fastest-known large-scale breakage along an Antarctic ice shelf. The study, recently published in AGU Advances, shows that a 6.5-mile (10.5 kilometer) crack formed in 2012 on Pine Island Glacier — a retreating ice shelf that holds back the larger West Antarctic ice sheet — in about 5 and a half minutes. That means the rift opened at about 115 feet (35 meters) per second, or about 80 miles per hour.

“This is to our knowledge the fastest rift-opening event that’s ever been observed,” said lead author Stephanie Olinger, who did the work as part of her doctoral research at the UW and Harvard University and is now a postdoctoral researcher at Stanford University. “This shows that under certain circumstances, an ice shelf can shatter. It tells us we need to look out for this type of behavior in the future, and it informs how we might go about describing these fractures in large-scale ice sheet models.”

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