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

Wednesday, April 26, 2023

Prolonged droughts likely spelled the end for Indus megacities

A section through the Dharamjali stalagmite that the authors studied. 
Photo Credit: Alena Giesche

The beginning of this arid period — starting at around 4,200 years ago and lasting for over two centuries — coincides with the reorganization of the metropolis-building Indus Civilization, which spanned present-day Pakistan and India.

The research identified three protracted droughts — each lasting between 25 and 90 years — during this arid period. “We find clear evidence that this interval was not a short-term crisis but a progressive transformation of the environmental conditions in which Indus people lived,” said study co-author Prof Cameron Petrie, from Cambridge’s Department of Archaeology.

The researchers charted historic rainfall by examining growth layers in a stalagmite collected from a cave near Pithoragarh, India. By measuring a range of environmental tracers — including oxygen, carbon and calcium isotopes — they obtained a reconstruction showing relative rainfall at seasonal resolution. They also used high-precision Uranium-series dating to get a handle on the age and duration of the droughts.

“Multiple lines of evidence allow us to piece together the nature of these droughts from different angles — and confirm they are in agreement,” said lead author of the research Alena Giesche, who conducted the research as part of her PhD in Cambridge’s Department of Earth Sciences.

Tuesday, April 25, 2023

Mysterious underwater acoustic world of British ponds revealed in new study

Old Sneed Park
Photo Credit: Dr Jack Greenhalgh

The previously hidden and diverse underwater acoustic world in British ponds has been revealed by a team of researchers at the University of Bristol.

Ponds are magnets for life and a lot of that life is very noisy. Water beetles, bugs, fish, frogs, and even aquatic plants all produce sound creating a diverse underwater orchestra that scientists are only just starting to understand.

Acoustic monitoring has been shown to effectively survey birds and monkeys in rainforests, and marine mammals in the oceans. However, freshwater environments have remained largely unexplored despite their diverse soundscapes.

“Ponds are packed full of bizarre and mysterious sounds made by scratching aquatic insects, booming fish, and popping plants. It’s like an underwater disco!” explained lead author Dr Jack Greenhalgh from Bristol’s School of Biological Sciences.

To better understand these mysterious soundscapes, the team collected 840 hours of underwater sound recordings from five ponds in the southwest of England using an underwater microphone (a hydrophone).

Monday, April 24, 2023

Mudskippers Could Be Key to Understanding Evolution of Blinking

Indian mudskipper P. septemradiatus
Photo Credit: Courtesy of Georgia Institute of Technology

Blinking is crucial for the eye. It’s how animals clean their eyes, protect them, and even communicate. But how and why did blinking originate? Researchers at the Georgia Institute of Technology, Seton Hill University, and Pennsylvania State University studied the mudskipper, an amphibious fish that spends most of its day on land, to better understand why blinking is a fundamental behavior for life on land.

Although mudskippers are distantly related to tetrapods, the group that includes humans and other four-limbed vertebrates, researchers believed studying the fish could unlock how blinking evolved as these animals began to move on land. 

The research team, which included several undergraduates, published their findings in the paper, “The Origin of Blinking in Both Mudskippers and Tetrapods Is Linked to Life on Land,” in Proceedings of the National Academies of Science.

“By comparing the anatomy and behavior of mudskippers to the fossil record of early tetrapods, we argue that blinking emerged in both groups as an adaptation to life on land,” said Tom Stewart, an assistant professor at Penn State and an author of the paper. “These results help us understand our own biology and raise a whole set of new questions about the variety of blinking behaviors we see in living species.”

Algae in Swedish lakes provide insights to how complex life on Earth developed

Lönsboda, Sweden
Photo Credit: Johanna Nilsson

By studying green algae in Swedish lakes, a research team, led by Lund University in Sweden, has succeeded in identifying which environmental conditions promote multicellularity. The results give us new clues to the amazing paths of evolution.

The evolution of multicellular life has played a pivotal role in shaping biological diversity. However, we have up until now known surprisingly little about the natural environmental conditions that favor the formation of multicellular groups.

The cooperation between cells within multicellular organisms has enabled eyes, wings and leaves to evolve. The predominant explanation for why multicellularity evolves is that being in a group enables species to better cope with environmental challenges – where being in a large group can, for instance, protect cells against being eaten.

"Our results challenge this idea, showing that multicellular groups form, not because they are inherently beneficial, but rather as a by-product of single-celled strategies to reduce environmental stress. In particular, cells produce a range of substances to protect themselves from the environment and these substances appear to prevent daughter cells from dispersing away from their mother cell", says Charlie Cornwallis, biology researcher at Lund University.

Thursday, April 20, 2023

A message to meteorite hunters: Put down your magnets!

Black Beauty, or NWA 7034, is thought to have formed at a time when the Red Planet harbored a magnetic field, much like the Earth does today. If the rock bears any trace of Mars’ ancient field, this could give scientists valuable clues to the planet’s past climate and composition.
Photo Credit: C Agee, Institute of Meteoritics, UNM; NASA

Each year, thousands of space rocks pierce through the Earth’s atmosphere and hit the ground as meteorites. These fragments of comets and asteroids can land anywhere but are most often spotted in open terrain, such as the deserts of Africa and the Antarctic blue ice, where a meteorite’s blackened exterior can stand out.

Still, these extraterrestrial remnants can resemble Earth rocks, and to tell the difference meteorite hunters often expose their “finds” to hand magnets, which can attract more strongly to metal-rich meteorites than to terrestrial rocks. Meteorite hunters, dealers, collectors, and curators often rely on hand magnets to verify a meteorite’s identity.

But a new MIT study finds that the same magnets used to identify a meteorite usually erase its magnetic memory. They show that exposure to a magnet can reorient a rock’s microscopic grains, undoing their original orientation and any trace of its magnetic origins.

The researchers make their case with Northwest Africa (NWA) 7034, a meteorite known in collectors’ circles as “Black Beauty” for its obsidian exterior. Multiple shards of the meteorite were first discovered in the deserts of northwest Africa, and scientists determined that the rock contained crystals that formed on Mars more than 4.4 billion years ago.

How bee-friendly is the forest?

A honeybee (Apis mellifera) collects honeydew on a fir tree. The study shows that the beech-dominated Steigerwald provides insufficient food resources for honeybees.
Photo Credit: Ingo Arndt

What role do forests play as a feeding habitat for honeybees? A team led by Würzburg biologist Dr. Benjamin Rutschmann investigated this question. For this purpose, the researchers used observation hives inside the Steigerwald.

Bees are generally associated with flowering meadows rather than with dense forests. Woodland, however, is considered the original habitat of the western honeybee (Apis mellifera), as it offers nesting sites in the form of tree cavities. Researchers at the Julius-Maximilians-Universität Würzburg (JMU) have now investigated the extent to which contemporary deciduous forests are suitable as foraging habitats for the busy insects.

For this purpose, Benjamin Rutschmann and Patrick Kohl installed twelve normally-sized honeybee colonies in observation hives across the Steigerwald – the respective proportion of forest in the surroundings varied for each bee colony. The two scientists conduct research at JMU in the Chair of Animal Ecology and Tropical Biology (Zoology III), which is headed by Professor Ingolf Steffan-Dewenter. The latter was also involved in the study, which has now appeared in the Journal of Applied Ecology.

Wednesday, April 19, 2023

Massive Caribbean sea urchin die-off caused by parasite

In a study led by Cornell microbiology professor Ian Hewson, scientists have discovered that a parasite is behind a severe die-off of long-spined sea urchins across the Caribbean Sea, which has had devastating consequences for coral reefs and surrounding marine ecosystems.
Video Credit: Noël Heaney/Cornell University 

Scientists have discovered that a parasite is behind a severe die-off of long-spined sea urchins across the Caribbean Sea, which has had devastating consequences for coral reefs and surrounding marine ecosystems.

The long-spined sea urchins (Diadema antillarum) serve as vital herbivores that graze on algae, which if left unchecked will outcompete corals for resources and space and blanket them, block light and kill them. By feeding on algae, the sea urchins are essential to maintaining coral health and balance in the marine ecosystem.

Diadema mortalities were first reported in St. Thomas in the U.S. Virgin Islands in late January 2022. By late March, the condition was found across the Lesser Antilles, Jamaica and the Mexican Caribbean. And by June of last year, it had been detected in most of the Greater Antilles, Florida and Curacao.

Prior to an experiment designed to verify the source of infections, a healthy sea urchin was swabbed to ensure it had never been exposed to the ciliate parasite.

Scientists have been trying to identify the cause of the mysterious illness, which has led to declines of between 85% and 95% compared to pre-mortality numbers in affected areas. When sea urchins die, they lose their spines and detach from their anchors.

Not so sweet after all: are candy-striped spiders a threat to ecosystems across North America?

candy-striped spider Enoplognatha ovata
Photo Credit: Syrio (CC BY-SA 4.0)

For years, pollinator declines have been a pressing issue for ecosystem health and food security in the face of climate change and human impacts on the environment. Even in their sleep, pollinating insects cannot catch a break – for fear they’ll be taken down by a small, but mighty predator: the candy-striped spider. Research published in Ecology took a closer look into this spider’s behavior and found that the result of their stealth attacks could have substantial impacts on ecosystems.

Most likely accidentally introduced to both the East and West Coasts a little over a century ago, the candy-striped spider is a very common spider in North America. The spider's striking color varieties have attracted much research into their genetics, but before now very little was known about their behavior.

A once-stable glacier in Greenland is now rapidly disappearing


The K.J.V. Steenstrup Glacier during the summer melt season in 2016.
Photo Credit: NASA/John Sonntag.

As climate change causes ocean temperatures to rise, one of Greenland’s previously most stable glaciers is now retreating at an unprecedented rate, according to a new study. 

Led by researchers at The Ohio State University, a team found that between 2018 and 2021, Steenstrup Glacier in Greenland has retreated about 5 miles, thinned about 20%, doubled in the amount of ice it discharges into the ocean, and quadrupled in velocity. According to the study, such a rapid change is so extraordinary among Greenland ice formations that it now places Steenstrup in the top 10% of glaciers that contribute to the entire region’s total ice discharge.

The study was published today in Nature Communications

The Steenstrup Glacier is part of The Greenland Ice Sheet, a body of ice that covers nearly 80% of the world’s largest island, which is also the single largest contributor to global sea rise from the cryosphere, the portion of Earth’s ecosystem that includes all of its frozen water. While the region plays a crucial part in balancing the global climate system, the area is steadily shrinking as it sheds hundreds of billions of tons of ice each year because of global warming.

Tuesday, April 18, 2023

Scientists Study Whether Flows in the Earth's Core Can Affect Global Processes

Scientists are trying to answer the question of how changes in the Earth's rotational speed affect tectonic activity.
Photo Credit: NASA

Scientists from Moscow State University, together with colleagues from the Ural Federal University, the University of Helsinki and the University of Oxford, have studied the response of viscous incompressible fluid flow in a spherical layer of the Earth to random external forcing. The results help scientists understand how random changes in the planet's rotation speed affect the tectonic activity that leads to earthquakes, volcanic eruptions and tsunamis. The research has been published in the Philosophical Transactions of the Royal Society, the world's oldest scientific journal. 

"In our research we considered flows of a viscous incompressible fluid induced either by rotation of the inner sphere only or by co-rotation of the spheres. The magnitude of the rotation speed of the inner sphere was subjected to the influence of noise - random deviations in time of the angular rotation speed from the average values. Mean flow generation was found to occur under the action of additive noise. Calculations have shown that the response to noise depends on how the flow was created - by rotation of the inner sphere only or by rotation of both spheres," explains Maria Gritsevich, Senior Researcher at the Ural Federal University and Assistant Professor at the University of Helsinki.

Monday, April 17, 2023

New approach estimates long-term coastal cliff loss

Jane Willenbring sampling shore platform bedrock in Del Mar with a hammer and chisel.
Photo Credit: Travis Clow

A new method for estimating cliff loss over thousands of years in Del Mar, California, may help reveal some of the long-term drivers of coastal cliff loss in the state.

In parts of California’s iconic mountainous coasts, breathtaking beauty is punctuated by brusque signs warning spectators to stay back from unstable cliffs. The dangers of coastal erosion are an all-too-familiar reality for the modern residents of these communities. Now, with a new tool, researchers are bringing historical perspective to the hotly debated topic of how to manage these disappearing coastlines.

Using a model that incorporates measurements of the amount of time coastal cliffs and their remnant deposits were exposed at the Earth’s surface, Stanford researchers found that the rate of cliff erosion in the past 100 years is similar to that of the past 2,000 years. The proof-of-concept, published in the Journal of Geophysical Research: Earth Surface April 17, opens the possibility of using this new approach to understand the long-term history of coastal cliff erosion, or retreat, in other parts of the state. The work was conducted in Del Mar, California, a beach town in San Diego County with infrastructure atop its coastal bluffs.

Female butterflies breed despite male shortage

Monarch Butterfly
Photo Credit: Erin Minuskin

Female monarch butterflies have no trouble finding a mate – even when a parasite kills most of the males, new research shows.

Some females carry a parasite called Spiroplasma that kills all their male offspring, meaning highly infected populations have very few males.

But the new study – by the universities of Exeter, Rwanda and Edinburgh, and the Dian Fossey Gorilla Fund – found females mated about 1.5 times on average, regardless of how many males were around.

The male proportion dropped below 10% in some cases, but it appears the remaining hard-working males managed to breed with most of the available females.

10-20% of females remained unmated, only slightly higher than the expected average in a population with plenty of males (5-10%).

Saturday, April 15, 2023

2022 Tongan volcanic explosion was largest natural explosion in over a century

On January 14, 2022, at approximately 4:20am local time UTC a huge eruption occurred at the Hunga Tonga-Hunga Ha’apai underwater volcano, located about 65km (40 miles) north of Tonga’s capital, Nuku’alofa, which is part of a vast arc of volcanoes and ocean trenches known as the Pacific “Ring of Fire”. 
Image Credit: © 2022 European Space Agency - ESA, produced from ESA remote sensing data, image processed by ESA. Radiometrically enhanced by the University of Miami Center for Southeastern Tropical Advanced Remote Sensing (CSTARS)

The 2022 eruption of a submarine volcano in Tonga was more powerful than the largest U.S. nuclear explosion, according to a new study led by scientists at the University of Miami Rosenstiel School of Marine, Atmospheric, and Earth Science and the Khaled bin Sultan Living Oceans Foundation.  

The 15-megaton volcanic explosion from Hunga Tonga-Hunga Ha'apai, one of the largest natural explosions in more than a century, generated a mega-tsunami with waves up to 45-meters high (148 feet) along the coast of Tonga’s Tofua Island and waves up to 17 meters (56 feet) on Tongatapu, the country’s most populated island.

Wednesday, April 12, 2023

Scientists develop new way to measure wind

Photo Credit: Zbynek Burival

Using data from two NOAA satellites, University of Arizona researchers developed an algorithm for measuring wind via water vapor.

Wind speed and direction provide clues for forecasting weather patterns. In fact, wind influences cloud formation by bringing water vapor together. Atmospheric scientists have now found a novel way of measuring wind – by developing an algorithm that uses data from water vapor movements. This could help predict extreme events like hurricanes and storms.

A study published by University of Arizona researchers in the journal Geophysical Research Letters provides, for the first time, data on the vertical distribution of horizontal winds over the tropics and midlatitudes. The researchers got the water vapor movement data by using two operational satellites of the National Oceanic and Atmospheric Administration, or NOAA, the federal agency for weather forecasting.

Wind brings everything else in the atmosphere together, including clouds, aerosols, water vapor, precipitation and radiation, said Xubin Zeng, co-author of the study and the director of the Climate Dynamics and Hydrometeorology Collaborative at UArizona. But it has remained somewhat elusive.

How did Earth get its water?

Stock photo

For decades, what researchers knew about planet formation was based primarily on our own Solar System. However, the explosion of exoplanet research over the past decade informed a new approach to modeling the Earth’s embryonic state.

Our planet’s water could have originated from interactions between the hydrogen-rich atmospheres and magma oceans of the planetary embryos that comprised Earth’s formative years, according to new work from Carnegie Science’s Anat Shahar and UCLA’s Edward Young and Hilke Schlichting. Their findings, which could explain the origins of Earth’s signature features, are published in Nature.

For decades, what researchers knew about planet formation was based primarily on our own Solar System. Although there are some active debates about the formation of gas giants like Jupiter and Saturn, it is widely agreed upon that Earth and the other rocky planets accreted from the disk of dust and gas that surrounded our Sun in its youth.

As increasingly larger objects crashed into each other, the baby planetesimals that eventually formed Earth grew both larger and hotter, melting into a vast magma ocean due to the heat of collisions and radioactive elements. Over time, as the planet cooled, the densest material sank inward, separating Earth into three distinct layers—the metallic core, and the rocky, silicate mantle and crust.

ORNL, NOAA launch new supercomputer for climate science research

Photo Credit: Genevieve Martin/ORNL

Oak Ridge National Laboratory, in partnership with the National Oceanic and Atmospheric Administration, is launching a new supercomputer dedicated to climate science research. The new system is the fifth supercomputer to be installed and run by the National Climate-Computing Research Center at ORNL.

The NCRC was established in 2009 as part of a strategic partnership between NOAA and the U.S. Department of Energy and is responsible for the procurement, installation, testing and operation of several supercomputers dedicated to climate modeling and simulations. The goal of the partnership is to increase NOAA’s climate modeling capabilities to further critical climate research. To that end, the NCRC has installed a series of increasingly powerful computers since 2010, each of them formally named Gaea. The latest system, also referred to as C5, is an HPE Cray machine with over 10 petaflops — or 10 million billion calculations per second — of peak theoretical performance — almost double the power of the two previous systems combined.

Severe droughts devastate eucalyptus trees that pre-date Ice Age

Researchers documenting the loss of red stringybark trees in the Clare Valley, SA.
Photo Credit: Courtesy of University of South Australia

South Australian scientists have documented the catastrophic decline of a stand of red stringybark in the Clare Valley, a tree species that has survived in the region for 40,000 years but is now at risk of extinction due to climate change.

Two severe droughts driven by climate change since 2000 are blamed for “staggering losses” of an isolated population of the South Australian species Eucalyptus macrorhyncha  in the Spring Gully Conservation Park.

Multiple surveys led by University of South Australia environmental biologists Associate Professor Gunnar Keppel and Udo Sarnow have recorded tree and biomass losses of more than 40 per cent, during the Millennium Drought from 2000-2009 and the Big Dry from 2017-2019.

More than 400 trees were monitored over 15 years, within two years of their dieback first being reported in 2007.

Tuesday, April 11, 2023

USF geoscientist discovers new phosphorus material after New Port Richey lightning strike

Matthew Pasek
Courtesy of University of South Florida

After lightning struck a tree in a New Port Richey neighborhood, a University of South Florida professor discovered the strike led to the formation of a new phosphorus material. It was found in a rock – the first time in solid form on Earth – and could represent a member of a new mineral group. 

“We have never seen this material occur naturally on Earth – minerals similar to it can be found in meteorites and space, but we've never seen this exact material anywhere,” said geoscientist Matthew Pasek. 

In a recent study published in Communications Earth & Environment, Pasek examines how high-energy events, such as lightning, can cause unique chemical reactions, and in this instance, result in a new material – one that is transitional between space minerals and minerals found on Earth. 

“When lightning strikes a tree, the ground typically explodes out and the surrounding grass dies, forming a scar and sending electric discharge through nearby rock, soil and sand, forming fulgurites, also known as ‘fossilized lightning’,” Pasek said. 

Thursday, March 30, 2023

Was plate tectonics occurring when life first formed on Earth?

Plate tectonics melts and mixes rocks to create magmas with specific chemical makeups. Rochester geologists are using that chemical evidence to unlock information about plate tectonic activity on Earth more than 4 billion years ago.
Photo Credit: Tetiana Grypachevska

Zircon crystals and magmas reveal new information about plate tectonic activity on Earth billions of years ago.

Earth is a dynamic and constantly changing planet. From the formation of mountains and oceans to the eruption of volcanoes, the surface of our planet is in a constant state of flux. At the heart of these changes lies the powerful force of plate tectonics—the movements of Earth’s crustal plates. This fundamental process has shaped the current topography of our planet and continues to play a role in its future.

But what was plate tectonic activity like during early Earth? And was the process even occurring during the time when life is thought to have formed?

“The dynamic tectonic nature of the modern Earth is one of the reasons why life exists today,” says Wriju Chowdhury, a postdoctoral research associate in the lab of Dustin Trail, an associate professor of earth and environmental sciences at the University of Rochester. “Exploring the geodynamics and the lithological diversity of the early Earth could lead to revelations of how life first began on our planet.”

Wednesday, March 29, 2023

Deep ocean currents around Antarctica headed for collapse

Direct measurements taken from the deep ocean have established that warming is already underway.
Photo Credit: Pixabay

Antarctic circulation could slow by more than 40 per cent over the next three decades, with significant implications for oceans and the climate.

The deep ocean circulation that forms around Antarctica could be headed for collapse, say scientists.

Such a decline would stagnate the bottom of the oceans and affect climate and marine ecosystems for centuries to come.

The results are detailed in a new study coordinated by Scientia Professor Matthew England, Deputy Director of the ARC Centre for Excellence in Antarctic Science (ACEAS) at UNSW Sydney. The work, published today in Nature, includes lead author Dr Qian Li – formerly from UNSW and now at the Massachusetts Institute of Technology (MIT) – as well as co-authors from the Australian National University (ANU) and CSIRO.

Cold water that sinks near Antarctica drives the deepest flow of the overturning circulation – a network of currents that spans the world’s oceans. The overturning carries heat, carbon, oxygen and nutrients around the globe. This influences climate, sea level and the productivity of marine ecosystems. 

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