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

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.”

Scientists provide first detailed estimates of how much sediment is supplied to coral islands from the reef system

The island of Dhigelabadhoo in the Maldives is the main field site of the ARISE program
Credit: University of Plymouth

Scientists have produced the first detailed estimates of how much sediment is transported onto the shores of coral reef islands, and how that might enable them to withstand the future threats posed by climate change.

Coral reef islands are low-lying accumulations of sand and gravel-sized sediment deposited on coral reef surfaces.

The sediments are derived from the broken down remains of corals and other organisms that grow on the surrounding reef. Therefore, the rate of supply of sediment from reefs is a critical control on island formation and future change.

The international team of researchers used data available for 28 reef islands in the Indian and Pacific Oceans, widely acknowledged to be among the world’s most vulnerable environments to rising seas.

By identifying the amount of sediment present within reef islands, and comparing this against the known age of the islands, they were able to determine the average amount of sediment delivered to the islands from surrounding coral reefs over their histories.

Tuesday, February 27, 2024

Glacier melting destroys important climate data archive

Corbassière glacier at Grand Combin in the canton of Valais
Photo Credit: Peter Meyer-Herzog

As part of the Ice Memory initiative, PSI researchers, with colleagues from the University of Fribourg and Ca’ Foscari University of Venice as well as the Institute of Polar Sciences of the Italian National Research Council (CNR), analyzed ice cores drilled in 2018 and 2020 from the Corbassière glacier at Grand Combin in the canton of Valais. A comparison of the two sets of ice cores published in Nature Geoscience shows: Global warming has made at least this glacier unusable as a climate archive.

Reliable information about the past climate and air pollution can no longer be obtained from the Corbassière glacier in the Grand Combin massif, because alpine glacier melting is progressing more rapidly than previously assumed. This sobering conclusion was reached by researchers led by Margit Schwikowski, head of the Laboratory for Environmental Chemistry at PSI, and Carla Huber, PhD student and first author of the study, when they compared the signatures of particulate matter locked in the annual layers of the ice. Glaciers are invaluable for climate research. The climatic conditions and atmospheric compositions of past ages are preserved in their ice. Therefore, they can serve, in much the same way as tree rings and ocean sediments, as a so-called climate archive for research.

Normally, the amount of particle-bound trace substances in ice fluctuates with the seasons. SubstPeter Meyer-Herzogances such as ammonium, nitrate, and sulfate come from the air and are deposited on the glacier through snowfall: The concentrations are high in summer and low in winter, because lower amounts of polluted air can rise from the valley when the air is cold. The 2018 ice core, which was drilled from depths of up to 14 meters during a preliminary study and contains deposits dating back to 2011, shows these fluctuations as expected. But the core from 2020, from a depth of up to 18 metres – drilled under the leadership of PSI researcher Theo Jenk – shows those fluctuations only for the upper three or four annual layers. Deeper in the ice – that is, farther in the past – the curve indicating the concentration of trace substances becomes noticeably flatter, and the total amount is lower. Schwikowski’s team reports on this in the current issue of the journal Nature Geoscience.

Vital Seagrasses in Gulf of Mexico Are Retreating Amid Rapid Sea Level Rise

Marine Science professor Ken Dunton (left) and doctoral student Kyle Capistrant-Fossa (right) in the Gulf of Mexico.
Photo Credit: Courtesy of University of Texas at Austin

The Gulf of Mexico is experiencing sea level rise two to three times as fast as the global average due to a combination of warmer waters and wind circulation patterns. Now, a newly released long-term study from marine scientists at The University of Texas at Austin has found rising sea levels can be linked to a loss of valuable seagrass habitats in Texas.

The paper appears in Communications Earth & Environment.

Seagrasses are recognized globally as a foundation species that play a key role in supporting fisheries and mitigating climate change, efficiently storing substantial amounts of carbon. Meadows occur in shallow waters, and the species are dependent on light for photosynthesis and growth. The researchers are the first to find that sea level rise is yet another human impact that is responsible for the worldwide decline in seagrasses.

Ken Dunton, a professor in UT’s Marine Science Institute, and Kyle Capistrant-Fossa, a doctoral student, made the discovery while examining a 30-year database of observations that Dunton had collected at his study site in the Laguna Madre next to Padre Island. Capistrant-Fossa found that the slow loss of vegetation at the site during the past decade was also coincident with an unprecedented rise in sea level. They also found that seagrasses were disappearing from their historical deeper water ranges throughout the Upper Laguna Madre. But they noted that these losses could be compensated by plant expansion into areas that were once too shallow.

Significant glacial retreat in West Antarctica began in 1940s

Thwaites Glacier from above.
Photo Credit: Ted Scambos.

A new study, involving researchers from British Antarctic Survey, has found that significant thinning and retreat of the vast Thwaites Glacier began in the 1940s.

Accelerating ice loss has been observed since the 1970s, but its unclear when this significant melting initiated – until now. These results coincide with previous work that found the Pine Island Glacier also began its retreat at this time. Climate models indicate that anthropogenic warming has increasingly driven West Antarctic ice loss since that time, and has prevented these glaciers from recovering.

James Smith, a marine geologist at British Antarctic Survey said:

“Our previous work in 2016 provided the first direct evidence that neighbouring Pine Island Glacier started to retreat in the 1940s. However, that was just one glacier draining into the huge Amundsen Sea Embayment. Now that we know Thwaites glacier also started to retreat around the same time is really significant. It demonstrates that glaciers in this area were responding synchronously to an external climatic driver.”

“A significant implication of our findings is that once an ice sheet retreat is set in motion it can continue for decades, even if what started it gets no worse. It is possible that the changes we see today on Thwaites and Pine Island glaciers – and potentially across the entire Amundsen Sea Embayment – were essentially set in motion in the 1940s.”

‘Janitors’ of the Sea: Overharvested Sea Cucumbers Play Crucial Role in Protecting Coral

Photo Credit: Cody Clements

Corals are foundational for ocean life. Known as the rainforests of the sea, they create habitats for 25% of all marine organisms, despite only covering less than 1% of the ocean’s area. 

Coral patches the width and height of basketball arenas, used to be common throughout the world’s oceans. But due to numerous human-generated stresses and coral disease, which is known to be associated with ocean sediments, most of the world’s coral is gone.

“It’s like if all the pine trees in Georgia disappeared over a period of 30 to 40 years,” said Mark Hay, Regents’ Chair and the Harry and Anna Teasley Chair in Environmental Biology in the School of Biological Sciences at the Georgia Institute of Technology. “Just imagine how that affects biodiversity and ecosystems of the ocean.”

In first-of-its-kind research, Hay, along with research scientist Cody Clements, discovered a crucial missing element that plays a profound role in keeping coral healthy — an animal of overlooked importance known as a sea cucumber.

Study Offers Improved Look at Earth’s Ionosphere

Radio signal plasma wave from a parallel magnetic field. This animation shows the Faraday rotation phenomena in black. The grid at the end of the propagation path is the antenna, and the black line shows how the plane of polarization of the radio signal projects onto it.
Image Credit: E. Jensen/PSI.

New measuring techniques will enable improved measurements of the Earth’s ionosphere, a key to studying and reducing the impact of space weather.

Radio signals have been used to study the density of plasma since the 1920s. Transmitting radio sources include ground-based ionosondes (special radar for the examination of the ionosphere), astronomical phenomena such as pulsars and more recently spacecraft signals used for transmitting data. For example, Global Positioning Satellites (GPS) radio signals are used to measure the density of Earth’s ionosphere. However, the response of the radio signal to the ionospheric plasma is more complicated than simply varying as a function of density. The Earth’s magnetic field affects its electromagnetic wave fluctuations as well. For example, Faraday rotation is a well-known phenomenon, as shown in the image above. But, as a technique for measuring magnetic field, Faraday rotation is limited to just the portion that is oriented in the correct direction. Our discovery complements Faraday rotation enabling a complete measurement of magnetic field strength.

Friday, February 23, 2024

Side effects of wide scale forestation could reduce carbon removal benefits by up to a third

Combining forestation with other climate mitigation strategies is vital for more effective long-term climate action
Photo Credit: Andrew Coelho

The side effects of large-scale forestation initiatives could reduce the CO2 removal benefits by up to a third, a pioneering study has found.

The research, led by scientists at the University of Sheffield and published today (Thursday 22 February 2024) in the journal Science, provides a new insight into the broader impacts of forestation on the Earth's climate, indicating that its positive impact is potentially smaller than previously thought. 

Carbon removal strategies, such as forestation, alongside greenhouse gas emissions reduction efforts, have been recognized by the IPCC as essential measures to mitigate the risk of dangerous future climate change. 

By simulating global forest expansion with advanced computer modelling techniques, academics from the University of Sheffield, in collaboration with the Universities of Leeds and Cambridge, and NCAR and WWF, found that while forestation increases absorption of carbon dioxide from the atmosphere, other complex Earth System responses could together partially offset these benefits by up to a third.

Dr James Weber, from the University of Sheffield’s School of Biosciences and lead author of the study, said: “The public are bombarded with messages about climate change, and the suggestion that you can plant trees to offset your carbon emissions is widespread. Many businesses now offer to plant a tree with a purchase, and some countries plan to expand, conserve, and restore forests. 

Thursday, February 22, 2024

RIT researchers highlight the changing connectivity of the Amazon rainforest to global climate

The Amazon rainforest is one of the largest ecosystems in the world, and its climate is changing due to warming and deforestation. Researchers from Rochester Institute of Technology studied the region’s connectivity to the global climate crisis.
Photo Credit: Arın Turkay

The Amazon rainforest is one of the largest ecosystems in the world, and its climate is changing due to warming and deforestation. Researchers from Rochester Institute of Technology studied the region’s connectivity to the global climate crisis.

The Amazon rainforest is a unique region where climatologists have studied the effects of warming and deforestation for decades. With the global climate crisis becoming more evident, a new study is linking the Amazon to climate change around the rest of the world.

Scholars at Rochester Institute of Technology have looked at the issue from a mathematical perspective and have reinforced the idea that the Amazon’s climate is very much connected to the global climate system and that the connectivity is reconfiguring.

Mathematical modeling Ph.D. student Adam Giammarese ’21 BS/MS (applied mathematics) and Assistant Professor Nishant Malik recently had their findings published as a featured article in Chaos: An Interdisciplinary Journal of Nonlinear Science. Giammarese began the work as part of RIT’s Research Experience for Undergraduates (REU) program, along with co-author Jacob Brown.

The team used both old and new approaches to climate network analysis for their research, analyzing decades of temperature data.

Wednesday, February 21, 2024

Cloud model could help with climate research

Clouds have a number of important functions. They act as reflectors whereby water droplets in the cloud reflect radiation back to the Earth, which contributes to the greenhouse effect.
Photo Credit: Rodion Kutsaiev

When clouds meet clear skies, cloud droplets evaporate as they mix with dry air. A new study involving researchers from the University of Gothenburg has succeeded in capturing what happens in a model. Ultimately, this could lead to more accurate climate modeling in the future.

The clouds in the sky have a significant impact on our climate. Not only do they produce precipitation and provide shade from the sun, they also act as large reflectors that prevent the radiation of heat from the Earth – commonly known as the greenhouse effect.

“Although clouds have been studied for a long time, they are one of the biggest sources of uncertainty in climate models,” explains Bernhard Mehlig, Professor of Complex Systems at the University of Gothenburg. “This is because there are so many factors that determine how the clouds affect radiation. And the turbulence in the atmosphere means that everything is in constant motion. This makes things even more complicated.”

Monday, February 19, 2024

Methane Mystery

Maggie Capooci stands at the St. Jones Reserve where the team conducted its research.
Photo Credits: Evan Krape and Andrew Hill

Tidal salt marshes are fairly common across the Mid-Atlantic. These coastal ecosystems provide habitat for plants, birds and fish. Existing at the intersection of land and sea, tidal salt marshes act as armor against hurricanes and shoreline erosion.

Tidal salt marshes are also a powerful tool to combat climate change, said Rodrigo Vargas, an ecosystem ecology and environmental change professor in the Department of Plant and Soil Sciences at the University of Delaware. These ecosystems absorb the greenhouse gas carbon dioxide from the atmosphere, and their soils act as a carbon vault. 

“These ecosystems are threatened across the world. They are disappearing because of different problems, such as land use change and sea level rise,” Vargas said. “But they store a lot of carbon. So, there is a big concern about what will happen to salt marshes now under climate change and what is going to happen with the carbon stored in these ecosystems.” 

If tidal salt marshes shrink or disappear because of climate change or how human activities have transformed natural landscapes, could all the carbon they have stored go back into the atmosphere and further contribute to the warming of the Earth? Vargas said this is an important question that scientists are working on.

Tidal salt marsh soils are great at storing carbon because they're often flooded and have salty water. These conditions lower oxygen levels and make it difficult for most microorganisms to consume the carbon in the soil. However, some microorganisms called methyl-methanogens can eat some of the carbon in the soil and produce methane under these conditions. That’s a far more powerful greenhouse gas with the ability to heat up the Earth more intensely than carbon dioxide. In some marshes, the amount of methane produced and emitted can offset the amount of carbon captured by the ecosystem in the growing season. 

Spy-satellite images offer insights into historical ecosystem changes

A large forest clear-cut from the 1960s in the vicinity of a one-hectare forest research plot in the Southern Black Forest Region. Although much of the area is forested today, historical harvests have changed the forest structure and composition.
Left: Historical spy-satellite image. Right: Current Google Earth Image.
Image Credit: Courtesy of University of Freiburg

A large number of historical spy-satellite photographs from the Cold War Era were declassified decades ago. This valuable remote sensing data has been utilized by scientists across a wide range of disciplines from archaeology to civil engineering. However, its use in ecology and conservation remains limited. A new study led by Dr. Catalina Munteanu from the Faculty of Environment and Natural Resources at the University of Freiburg, Germany, aims to advance the application of declassified satellite data in the fields of ecology and conservation. Leveraging recent progress in image processing and analysis, these globally available black-and-white images can offer better insights into the historical changes of ecosystems, species populations or changes in human influences on the environment dating back to the 1960s, the researchers suggest.

Thursday, February 15, 2024

The ties that bind

The soils in many iconic Australian landscapes, like the outback and deserts, are colored red by an abundant mineral known as goethite. This mineral tends to lock away trace metals over time, according to research from Washington University in St. Louis
Photo Credit: Nathan March

Trace metals are nutrient elements, like zinc, that animals and plants need in small amounts to function properly. Animals generally get trace metals in their diets or through environmental exposures, while plants take their trace minerals up from soil. If we get too little, we may experience a deficiency, but the opposite can also be true: too much of a trace metal can be toxic.

Scientists believe that up to 50% of the trace metals in soils and urban environments may be bound to the surfaces of mineral grains — rendering the trace metals essentially unavailable for consumption or exposure. Researchers at Washington University in St. Louis wondered what holds them in place.

“When minerals bind trace metals, we often assume that they act like a sponge,” said Jeffrey G. Catalano, a professor of earth, environmental and planetary sciences and the director of environmental studies in Arts & Sciences. “But sometimes, they bind trace metals and won’t let them go. That is great when they are contaminants, but bad when they are serving as micronutrients.”

In a study published in the journal Environmental Science & Technology, Catalano and Greg Ledingham, a PhD candidate in his laboratory, discovered that a common mineral called goethite — an iron-rich mineral that is abundant in soils that cover the Earth — tends to incorporate trace metals into its structure over time, binding the metals in such a way that it locks them out of circulation.

Tuesday, February 13, 2024

Satellites unveil the size and nature of the world’s coral reefs

A satellite photo from the Allen Coral Atlas showing shallow coral reefs off Fiji
Image Credit: Courtesy of Allen Coral Atlas

University of Queensland-led research has shown there is more coral reef area across the globe than previously thought, with detailed satellite mapping helping to conserve these vital ecosystems.

Dr Mitchell Lyons from UQ’s School of the Environment, working as part of the Allen Coral Atlas project, said scientists have now identified 348,000 square kilometers of shallow coral reefs, up to 20-30 meters deep.

“This revises up our previous estimate of shallow reefs in the world’s oceans,” Dr Lyons said.

“Importantly, the high-resolution, up-to-date mapping satellite technology also allows us to see what these habitats are made from.

“We’ve found 80,000 square kilometers of reef have a hard bottom, where coral tends to grow, as opposed to soft bottom like sand, rubble or seagrass.

Monday, February 12, 2024

Riverine fish numbers increase amidst environmental challenges

Surprising trends in the abundance and species richness of riverine fish across the globe have been unveiled in a new study.
Photo Credit: Brandon

A new study, conducted by scientists at the University of Sheffield, has found a significant increase in the number and diversity of riverine fish species across the planet over the past 30 years

Contrary to conventional expectations, increases in fish species that live in rivers are concentrated in the most degraded areas

Although researchers found positive trends in riverine fish communities, a surge in the prevalence of non-native species poses a threat to the delicate balance of native fish

Surprising trends in the abundance and species richness of riverine fish across the globe have been unveiled in a new study. 

Until now, it was a common scientific belief that increases in species richness and abundance in freshwater ecosystems were as a result of the recent improvement of water quality in historically industrialized regions.

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