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

Tuesday, December 13, 2022

Changes in Earth’s orbit may have triggered ancient warming event

Victoria Fortiz (right), then a graduate student at Penn State, and Jean Self-Trail, a research geologist at the U.S. Geological Survey, work on a core sample from the Howards Tract site in Maryland
Photo Credit: Pennsylvania State University

Changes in Earth’s orbit that favored hotter conditions may have helped trigger a rapid global warming event 56 million years ago that is considered an analogue for modern climate change, according to an international team of scientists.

“The Paleocene-Eocene Thermal Maximum is the closest thing we have in the geologic record to anything like what we’re experiencing now and may experience in the future with climate change,” said Lee Kump, professor of geosciences at Penn State. “There has been a lot of interest in better resolving that history, and our work addresses important questions about what triggered the event and the rate of carbon emissions.”

The scientists analyzed core samples from a well-preserved record of the PETM near the Maryland coast using astrochronology, a technique for dating sediments against orbital patterns that occur over tens to hundreds of thousands of years, known as Milankovitch cycles.

They found the shape of Earth’s orbit, or eccentricity, and the wobble in its rotation, or precession, favored hotter conditions at the onset of the PETM and that these orbital configurations together may have played a role in triggering the event.

Monday, December 12, 2022

El Niño ‘flavors’ help unravel past variability, future response to climate change

Stream in Hilo.
Photo Credit: Pascal Debrunner

As with many natural phenomena, scientists look to the climate of the past to understand what may lie ahead as Earth warms. By assessing so-called ‘flavors’ of El Niño events in historical records and model simulations, researchers have a clearer picture of El Niño patterns over the past 12,000 years and are able to more accurately project future changes and impacts of this powerful force. The study, by scientists at the University of Hawaiʻi at Mānoa and University of Colorado Boulder, was published in Nature Communications.

The new set of climate model simulations developed and analyzed by Christina Karamperidou, lead author of the study and associate professor at UH Mānoa, and co-author Pedro DiNezio, associate professor at the University of Colorado Boulder, are the first to allow the study of changes in the frequency of El Niño flavors during the past 12,000 years.

This work offers new knowledge on how El Niño may respond to climate change and thus can help reduce these uncertainties in global climate models and offer more accurate predictions of El Niño impacts.

Fossil-Sorting Robots Will Help Researchers Study Oceans, Climate


Researchers have developed and demonstrated a robot capable of sorting, manipulating, and identifying microscopic marine fossils. The new technology automates a tedious process that plays a key role in advancing our understanding of the world’s oceans and climate – both today and in the prehistoric past.

“The beauty of this technology is that it is made using relatively inexpensive off-the-shelf components, and we are making both the designs and the artificial intelligence software open source,” says Edgar Lobaton, co-author of a paper on the work and an associate professor of electrical and computer engineering at North Carolina State University. “Our goal is to make this tool widely accessible, so that it can be used by as many researchers as possible to advance our understanding of oceans, biodiversity and climate.”

The technology, called Forabot, uses robotics and artificial intelligence to physically manipulate the remains of organisms called foraminifera, or forams, so that those remains can be isolated, imaged and identified.

Forams are protists, neither plant nor animal, and have been prevalent in our oceans for more than 100 million years. When forams die, they leave behind their tiny shells, mostly less than a millimeter wide. These shells give scientists insights into the characteristics of the oceans as they existed when the forams were alive. For example, different types of foram species thrive in different kinds of ocean environments, and chemical measurements can tell scientists about everything from the ocean’s chemistry to its temperature when the shell was being formed.

Thursday, December 8, 2022

Say Hello to the Toughest Material on Earth

Microscopy-generated images showing the path of a fracture and accompanying crystal structure deformation in the CrCoNi alloy at nanometer scale during stress testing at 20 kelvin (-424 F). The fracture is propagating from left to right.
Image Credit: Robert Ritchie/Berkeley Lab

Scientists have measured the highest toughness ever recorded, of any material, while investigating a metallic alloy made of chromium, cobalt, and nickel (CrCoNi). Not only is the metal extremely ductile – which, in materials science, means highly malleable – and impressively strong (meaning it resists permanent deformation), its strength and ductility improve as it gets colder. This runs counter to most other materials in existence.

The team, led by researchers from Lawrence Berkeley National Laboratory (Berkeley Lab) and Oak Ridge National Laboratory, published a study describing their record-breaking findings in Science. “When you design structural materials, you want them to be strong but also ductile and resistant to fracture,” said project co-lead Easo George, the Governor’s Chair for Advanced Alloy Theory and Development at ORNL and the University of Tennessee. “Typically, it’s a compromise between these properties. But this material is both, and instead of becoming brittle at low temperatures, it gets tougher.”

CrCoNi is a subset of a class of metals called high entropy alloys (HEAs). All the alloys in use today contain a high proportion of one element with lower amounts of additional elements added, but HEAs are made of an equal mix of each constituent element. These balanced atomic recipes appear to bestow some of these materials with an extraordinarily high combination of strength and ductility when stressed, which together make up what is termed “toughness.” HEAs have been a hot area of research since they were first developed about 20 years ago, but the technology required to push the materials to their limits in extreme tests was not available until recently.

Researcher Aims to Uncover Plant Invasions in the Tropics

Invasive plants are invading all major ecosystems across Central America compromising the conservation of native species.
Photo Credit: Julissa Rojas-Sandoval

Invasive species of plants have a knack for settling in new settings and making big changes to an ecosystem, even leading to extinctions of native species.

Assistant Research Professor in UConn’s Institute of the Environment Julissa Rojas-Sandoval explains that invasive plants are non-native species that have been introduced into new areas generally as a result of human activities, and that they are actively spreading, causing harm to the environment, the economy, and human health. Invasive plants may have significant long-term implications for the conservation of native biodiversity, but to combat the problem, we need to know which plants are invasive, where they’re from, and how they got there.

Rojas-Sandoval leads an international collaboration including researchers from all Central American countries, working together to compile the most comprehensive databases of invasive plant species in Central America. The collaboration is called FINCA: Flora Introduced and Naturalized in Central America, and their first paper was published this week in Biological Invasions.

The collaboration arose to meet a need, says Rojas-Sandoval. “While we have a good understanding of the processes and mechanisms of plant invasions in temperate regions, there is a huge gap in our knowledge about biological invasions in the tropics, and this lack of information is limiting our ability to respond to invasive plants.”

Environmental DNA uncovers a 2-million-year-old ecosystem in Greenland

Reconstruction of the Kap København formation two-million years ago, in a time where the temperature was significantly warmer than northernmost Greenland today.
Illustration Credit: Beth Zaiken.

Around 2 million years ago, climate in Greenland resembled the forecast of a future under global warming: with trees such as poplars and birch and animals like hare, lemmings, mastodons and reindeer.

Paleoclimatic records show strong polar amplification with annual temperatures of 11–19 degrees Celsius above current values. The biological communities inhabiting the Arctic during this time remain poorly known because animal fossils are rare.

An international team, including a researcher from Lawrence Livermore National Laboratory (LLNL), report the oldest ancient environmental DNA (eDNA) record to date, describing the rich plant and animal assemblages of the Kap København Formation in north Greenland that existed 2 million years ago. The research appears on the cover of the Dec. 7 issue of the journal Nature.

Ancient DNA has been used to map a two-million-year-old ecosystem, which weathered extreme climate change. Researchers hope the results could help to predict the long-term environmental toll of today’s global warming.

Mekong Delta will continue to be at risk for severe flooding

Mekong River Delta
Photo Credit: Tsuyoshi Watanabe

Reef corals provide an accurate, high-resolution record of the influence of the El Niño Southern Oscillation on rainfall, flooding and droughts in the Mekong River Delta, Vietnam.

The Mekong River Delta is the agricultural heartland of Vietnam; it is affected by droughts and flooding, which have become more severe in recent years. If severe weather events can be more accurately predicted, risk assessments in the regions can be improved. This, in turn, will reduce the negative effects of floods and droughts in the region.

A team led by Tsuyoshi Watanabe at Hokkaido University has revealed the clearest picture yet of how the El Niño Southern Oscillation (ENSO) affected rainfall in the Mekong Delta over the last hundred years. Their findings were published in the journal Scientific Reports. They correlated water salinity data from reef coral samples with historical weather records and uncovered that the ENSO has caused seasons of heavy and light rainfall, resulting in patterns of both flooding and droughts, respectively.

The ENSO occurs in the central and Eastern tropical Pacific Ocean, in irregular cycles of two to seven years. It consists of the El Niño (warming of the ocean surface), La Niña (cooling of the ocean surface) and neutral (neither warming, nor cooling).

Wednesday, December 7, 2022

Scientists Discovered Late Antique Ice Age Was Not Global

Map of the study areas and examples of three anomalous anatomical structures.
Photo Credit: Monika Grabkowska

The international group of scientists, which includes Ural dendrochronologists, found that between 536 and 550 years the temperature decreased only in the Northern Hemisphere. Scientists obtained data on trees in Eurasia, the Western and Southern Hemispheres. The results were published in Science Bulletin. The work was supported by the Russian Science Foundation (project No. 21-14-00330).

"We estimated the spatial scale of the events of the 536-540s using tree rings. We used "abnormal" rings as markers. One advantage of the approach is that the width of the annual rings responds to temperature changes mainly only in the polar regions and highlands, but abnormal rings form during extreme cold spells in trees in many regions of the Earth. Therefore, the work included data on 23 different points, including the Southern Hemisphere, that is much more than when using the width of the rings," says Rashit Khantemirov, co-author of the work, Leading Researcher of the Laboratory of Dendrochronology of the Institute of Plant and Animal Ecology, Ural Branch of the Russian Academy of Sciences, and Head Specialist of the Laboratory of Natural Science Methods in Humanities at Ural Federal University.

Harvesting Light to Grow Food and Clean Energy Together

Solar panels emit a red light over tomato plants growing in a research field at UC Davis in 2022. The work further tests the findings of a UC Davis study showing plants in agrivoltaic systems respond best to the red spectrum of light while blue light is better used for energy production.
Photo Credit: Andre Daccache/UC Davis

People are increasingly trying to grow both food and clean energy on the same land to help meet the challenges of climate change, drought and a growing global population that just topped 8 billion. This effort includes agrivoltaics, in which crops are grown under the shade of solar panels, ideally with less water.

Now scientists from the University of California, Davis, are investigating how to better harvest the sun — and its optimal light spectrum — to make agrivoltaic systems more efficient in arid agricultural regions like California.

Their study, published in Earth’s Future, a journal of the American Geophysical Union, found that the red part of the light spectrum is more efficient for growing plants, while the blue part of the spectrum is better used for solar production.

Tuesday, December 6, 2022

Researchers propose new structures to harvest untapped source of freshwater

“Eventually, we will need to find a way to increase the supply of fresh water as conservation and recycled water from existing sources, albeit essential, will not be sufficient to meet human needs. We think our newly proposed method can do that at large scales,” said Illinois professor Praveen Kumar. The illustration shows Kumar and his co-authors’ proposed approach for capturing moisture above ocean surfaces and transporting it to land for condensation. 
Illustration Credit: Courtesy Praveen Kumar and Nature Scientific Reports

Researchers said that an almost limitless supply of fresh water exists in the form of water vapor above Earth’s oceans, yet remains untapped. A new study from the University of Illinois Urbana-Champaign is the first to suggest an investment in new infrastructure capable of harvesting oceanic water vapor as a solution to limited supplies of fresh water in various locations around the world.

The study, led by civil and environmental engineering professor and Prairie Research Institute executive director Praveen Kumar, evaluated 14 water-stressed locations across the globe for the feasibility of a hypothetical structure capable of capturing water vapor from above the ocean and condensing it into fresh water – and do so in a manner that will remain feasible in the face of continued climate change.

Kumar, graduate student Afeefa Rahman and atmospheric sciences professor Francina Dominguez published their findings in the journal Nature Scientific Reports.

Forest Resilience Linked with Higher Mortality Risk in Western U.S.

A new study assesses decades of U.S. forest health data, revealing a twist in Western U.S. forest fate amid climate change — higher ecosystem resilience is linked with higher mortality risk
Photo Credit: Sarah Ardin

A forest’s resilience, or ability to absorb environmental disturbances, has long been thought to be a boost for its odds of survival against the looming threat of climate change.

But a new study suggests that for some Western U.S. forests, it’s quite the opposite.

In the journal Global Change Biology, researchers have published one of the first large-scale studies of U.S. forest land exploring the link between forest resilience and mortality.

The study is based on more than three decades of satellite image data used for assessing forest resilience, and more than two decades of ground observations of forest tree death across the continental United States.

The results show that while high ecosystem resilience correlates with low mortality in eastern forests, it is linked to high mortality in western regions.

“It’s a surprising finding. … It was widely assumed that greater forest resilience indicates lower mortality risk, but this relationship hadn’t been rigorously evaluated at such a large scale until now,” said Xiaonan Tai, assistant professor of biology at New Jersey Institute of Technology and the corresponding author.

Monday, December 5, 2022

Post-lockdown auto emissions can’t hide in the grass

Polluting clouds of exhaust fumes rise in the air.
Photo Credit: Gerd Altmann

University of California scientists have a new way to demonstrate which neighborhoods returned to pre-pandemic levels of air pollution after COVID restrictions ended.

Vehicle emissions are the biggest source of carbon dioxide in Southern California’s air. As people drove their cars far less in 2020 compared to 2019 due to the pandemic, there was a major drop in CO2 on regional highways. A new study published in AGU Advances using a mobile laboratory shows the CO2 drop was roughly 60%.

By analyzing grass samples from across the state, the same study also showed in fine detail that some parts of California were back to high levels of emissions by 2021, while others — generally in more affluent areas — were not.

“Community scientists sent us hundreds of wild grass samples. We analyzed them for radiocarbon content, which is a proxy for fossil fuel emissions,” said Francesca Hopkins, UC Riverside assistant professor of climate change and study co-author.

Wednesday, November 30, 2022

Tropical wildlife follow the same daily patterns worldwide

An elephant faces a camera trap in one of millions of photos analyzed for a new study led by a Rice University visiting student. The study found striking similarities in how rainforest animals across the world spend their days.
Resized Image using AI by SFLORG
Photo Credit: Courtesy of Lydia Beaudrot/Conservation International

How do animals in the wild use their time? A researcher at Rice University is part of a new study that shows what motivates the daily ramble of tropical populations.

The study by an international team that includes Rice bioscientist Lydia Beaudrot and is led by Andrea Vallejo-Vargas, a graduate student at the Norwegian University of Life Sciences and currently a visiting scholar at Rice, found that communities of mammals across the wet tropics divide their days in similar ways, all generally geared toward finding their next meal. (Or avoiding being the next meal.)

Using millions of images from camera trap networks in 16 protected forests around the world, they examined the relationship of mammal activities to body sizes and feeding routines to find common characteristics among diverse populations.

Their open-access study in Nature Communications confirms that despite their diversity, similar patterns dominate the days of wildlife in Africa, Asia and the Americas.

The study showed that the activity of herbivores and insectivores was largely influenced by temperature in the environment (in study-speak, “thermoregulatory constraints”). For instance, large African herbivores are seven times more likely to be nocturnal than smaller herbivores.

Tuesday, November 29, 2022

Major fires an increasing risk as the air gets thirstier, research shows

Researchers examined global climate and fire records for the world’s forests over the last 20 years, linking fire activity and a measure of the atmosphere’s thirst.
Photo Credit: Mike Newbry

Greater atmospheric demand for water means a dramatic increase in the risk of major fires in global forests unless we take urgent and effective climate action, new research finds.

Published in Nature Communications, researchers have examined global climate and fire records in all of the world’s forests over the last 20 years.

The researchers found that in all kinds of forests, there is a strong link between fire activity and vapor pressure deficit (VPD), which is a measure of the atmosphere’s thirst.

VPD is calculated from temperature and humidity. It describes the difference between how much moisture there is in the air, and how much moisture the air can hold when it’s saturated (which is when dew forms.) The greater this difference, or deficit, the greater the air’s drying power on fuels.

Importantly, warmer air can hold more water, which means that VPD increases – and fuels will dry out more often – with rising temperatures due to climate change.

Strongest Arctic cyclone on record led to surprising loss of sea ice

A ship-based view of the Arctic Ocean in October 2015, when the ocean’s surface is beginning to freeze. In January, when the massive 2022 cyclone occurred, large sections of the Arctic Ocean would be covered in a layer of sea ice.
Photo Credit: Ed Blanchard-Wrigglesworth/University of Washington

A warming climate is causing a decline in sea ice in the Arctic Ocean, where loss of sea ice has important ecological, economic and climate impacts. On top of this long-term shift due to climate change are weather events that affect the sea ice from week to week.

The strongest Arctic cyclone ever observed poleward of 70 degrees north latitude struck in January 2022 northeast of Greenland. A new analysis led by the University of Washington shows that while weather forecasts accurately predicted the storm, ice models seriously underestimated its impact on the region’s sea ice.

The study, published in October in the Journal of Geophysical Research–Atmospheres, suggests that existing models underestimate the impact of big waves on ice floes in the Arctic Ocean.

“The loss of sea ice in six days was the biggest change we could find in the historical observations since 1979, and the area of ice lost was 30% greater than the previous record,” said lead author Ed Blanchard-Wrigglesworth, a research assistant professor of atmospheric sciences at the UW. “The ice models did predict some loss, but only about half of what we saw in the real world.”

Monday, November 28, 2022

Study finds that big rains bring big algae blooms… eventually

Center for Limnology system engineer Mark Gahler, right, co-author of a new study on the relationship between big storms and algae blooms, and colleague Jonathon Thom collect Lake Mendota data from instruments aboard David Buoy.
Photo Credit: Paul Schramm / University of Wisconsin–Madison

In the lake-rich regions of the world, algae blooms are a growing problem. Not only are the floating green scums a nuisance for anyone hoping to enjoy the water, they can turn toxic and threaten public health.

The main driver behind these blooms is phosphorus, an element used widely in agriculture to fertilize crops, that can run from the land and into lakes — especially during heavy rains. A new study from the University of Wisconsin–Madison shows how soon after a storm phosphorous “loading” sparks algae explosions, but also describes the many other factors that weigh on when and whether the lake reaches a tipping point.

“The fact that you just had a big storm doesn’t mean now you’re going to get a big [algae] bloom. The blooms are much more complicated.” says Steve Carpenter, lead author of a report published in the Proceedings of the National Academy of the Sciences.

Squirrel sperm and feet tell a different climate change story

Cape ground squirrels are ecosystem engineers
Photo Credit: Gary Simons

Perhaps it’s time to replace the canary in a coal mine metaphor with a squirrel in the ground. Because two University of Manitoba studies found that climate change is altering ground squirrels’ sperm and feet, and this warns of big consequences potentially coming to endangered ecosystems.

These subtle squirrel changes concern UM researchers Jane Waterman and Miya Warrington, who tuned into them only recently and published their latest findings in the latest Journal of Mammalogy.

It began last year when they found that some male Richardson’s ground squirrels, a species found throughout the Canadian prairies, emerged from hibernation during a particularly warm winter with non-motile sperm. This non-lethal effect of climate change fortunately did not result in fewer young that year, although other negative consequences of males “shooting blanks” may emerge in other species or situations.

Intrigued by this finding, they then looked at what non-lethal affects climate change was having on African ground squirrels in the grasslands of South Africa.

Mussel survey reveals alarming degradation of River Thames ecosystem since the 1960s

Photo Credit: Gil Ndjouwou

The detailed study measured the change in size and number of all species of mussel in a stretch of the River Thames near Reading between 1964 and 2020.

The results were striking: not only had native populations severely declined, but the mussels that remained were much smaller for their age – reflecting slower growth.

Mussels are important in freshwater ecosystems because they filter the water and remove algae. As filter feeders they’re exposed to everything in the water, and this makes them a valuable indicator of ecosystem health. Mussel shells also provide places for other aquatic species to live.

“Mussels are a great indicator of the health of the river ecosystem. Such a massive decline in mussel biomass in the river is also likely to have a knock-on effect for other species, reducing the overall biodiversity,” said Isobel Ollard, a PhD student in the University of Cambridge’s Department of Zoology and first author of the report.

She added: “The depressed river mussel used to be quite widespread in the Thames, but this survey didn’t find a single one - which also raises concerns for the survival of this species.”

Thursday, November 24, 2022

Overgrazing is threatening global drylands

Sheep on Green Grass Field
Photo Credit: Gökçe Gök

The positive effects of grazing by livestock and wild herbivores can turn negative as temperatures become warmer.

Grazing is a trillion-dollar industry, and is particularly important in drylands, which cover about 40 percent of Earth's land surface and support half of the world’s livestock. Livestock are critical for food, shelter and a source of capital, but changing climates threaten livestock production and the livelihoods of billions of people worldwide.

An international team of scientists has published a study in the journal Science today with the first global estimates of how grazing will affect ecosystem services across the world’s drylands. The research, led by the Dryland Ecology and Global Change group in Spain with collaborators from UNSW Sydney, shows that grazing by livestock and wild herbivores in drylands can have positive effects on ecosystem services, but these effects can turn negative as Earth’s temperature becomes warmer.

Old World flycatchers’ family tree mapped

European robin in snow. A new study of Old World flycatcher family, to which these birds belong. The study comprises 92 per cent of the more than 300 species in this family. 
Photo Credit: Tomas Carlberg

The European robin’s closest relatives are found in tropical Africa. The European robin is therefore not closely related to the Japanese robin, despite their close similarity in appearance. This is confirmed by a new study of the Old World flycatcher family, to which these birds belong. The study comprises 92 per cent of the more than 300 species in this family.

“The fact that the European and Japanese robins are so similar-looking despite not being closely related is one of many examples of so-called convergent evolution in this group of birds. Similarities in appearance can evolve in distant relatives, e.g., as a result of similarities in lifestyle,” says Per Alström from Uppsala University, who is one of the researchers behind the study published in Molecular Phylogenetics and Evolution.

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