What we’re still learning about how trees grow

Fundamental questions remain about what factors limit tree growth. A new study may hold answers.

Peer-Reviewed Publication

UNIVERSITY OF UTAH

 

IMAGE: A CONIFER FOREST IN NORTHERN CALIFORNIA. view more 

CREDIT: ANTOINE CABON

What will happen to the world’s forests in a warming world? Will increased atmospheric carbon dioxide help trees grow? Or will extremes in temperature and precipitation hold growth back? That all depends on whether tree growth is more limited by the amount of photosynthesis or by the environmental conditions that affect tree cell growth—a fundamental question in tree biology, and one for which the answer wasn’t well understood, until now.

A study led by University of Utah researchers, with an international team of collaborators, finds that tree growth does not seem to be generally limited by photosynthesis but rather by cell growth. This suggests that we need to rethink the way we forecast forest growth in a changing climate, and that forests in the future may not be able to absorb as much carbon from the atmosphere as we thought.

“A tree growing is like a horse and cart system moving forward down the road,” says William Anderegg, an associate professor in the U’s School of Biological Sciences and principal investigator of the study. “But we basically don’t know if photosynthesis is the horse most often or if it’s cell expansion and division. This has been a longstanding and difficult question in the field. And it matters immensely for understanding how trees will respond to climate change.”

The study is published in Science and is funded by the U.S. Department of Agriculture, the David and Lucille Packard Foundation, the National Science Foundation, the U.S. Department of Energy and the Arctic Challenge for Sustainability II.

CAPTION

Wood cores prepared for measuring ring width.

CREDIT

Antoine Cabon

Source vs. sink 

We learned the basics in elementary school—trees produce their own food through photosynthesis, taking sunlight, carbon dioxide and water and turning it into leaves and wood.

There’s more to the story, though. To convert carbon gained from photosynthesis into wood requires wood cells to expand and divide.

So trees get carbon from the atmosphere through photosynthesis. This is the trees’ carbon source. They then spend that carbon to build new wood cells—the tree’s carbon sink.

If the trees’ growth is source-limited, then it’s limited only by how much photosynthesis the tree can carry out and tree growth would be relatively easy to predict in a mathematical model. So rising carbon dioxide in the atmosphere should ease that limitation and let trees grow more, right?

But if instead the trees’ growth is sink-limited, then the tree can only grow as fast as its cells can divide. Lots of factors can directly affect both photosynthesis and cell growth rate, including temperature and the availability of water or nutrients. So if trees are sink-limited, simulating their growth has to include the sink response to these factors.

The researchers tested that question by comparing the trees’ source and sink rates at sites in North America, Europe, Japan and Australia. Measuring carbon sink rates was relatively easy—the researchers just collected samples from trees that contained records of growth. “Extracting wood cores from tree stems and measuring the width of each ring on these cores essentially lets us reconstruct past tree growth,” says Antoine Cabon, a postdoctoral scholar in the School of Biological Sciences and lead author of the study.

Measuring carbon sources is tougher, but doable. Source data was measured with 78 eddy covariance towers, 30 feet tall or more, that measure carbon dioxide concentrations and wind speeds in three dimensions at the top of forest canopies, Cabon says. “Based on these measurements and some other calculations,” he says, “we can estimate the total forest photosynthesis of a forest stand.”

Decoupled

The researchers analyzed the data they collected, looking for evidence that tree growth and photosynthesis were processes that are linked, or coupled. They didn’t find it. When photosynthesis increased or decreased, there was not a parallel increase or decrease in tree growth.

“Strong coupling between photosynthesis and tree growth would be expected in the case where tree growth is source limited,” Cabon says. “The fact that we mostly observe a decoupling is our principal argument to conclude that tree growth is not source-limited.”

Surprisingly, the decoupling was seen in environments across the globe. Cabon says they did expect to see some decoupling in some places, but “we did not expect to see such a widespread pattern.”

The strength of coupling or decoupling between two processes can lie on a spectrum, so the researchers were interested in what conditions led to stronger or weaker decoupling. Fruit-bearing and flowering trees, for example, exhibited different source-sink relationships than conifers. More diversity in a forest increased coupling. Dense, covered leaf canopies decreased it.

Finally, coupling between photosynthesis and growth increased in warm and wet conditions, with the opposite also true: that in cold and dry conditions, trees are more limited by cell growth.

Cabon says that this last finding suggests that the source vs. sink issue depends on the tree’s environment and climate. “This means that climate change may reshape the distribution of source and sink limitations of the world forests,” he says.

A new way to look forward

The key takeaway is that vegetation models, which use mathematical equations and plant characteristics to estimate future forest growth, may need to be updated. “Virtually all these models assume that tree growth is source limited,” Cabon says.

For example, he says, current vegetation models predict that forests will thrive with higher atmospheric carbon dioxide. “The fact that tree growth is often sink limited means that for many forests this may not actually happen.”

That has additional implications: forests currently absorb and store about a quarter of our current carbon dioxide emissions. If forest growth slows down, so do forests’ ability to take in carbon, and their ability to slow climate change.

After publication, find the full study here.

Other authors of the study include Steven A. Kannenberg, University of Utah; Altaf Arain and Shawn McKenzie, McMaster University; Flurin Babst, Soumaya Belmecheri and David J. Moore, University of Arizona; Dennis Baldocchi, University of California, Berkeley; Nicolas Delpierre, Université Paris-Saclay; Rossella Guerrieri, University of Bologna; Justin T. Maxwell, Indiana University Bloomington; Frederick C. Meinzer and David Woodruff, USDA Forest Service, Pacific Northwest Research Station; Christoforos Pappas, Université du Québec à Montréal; Adrian V. Rocha, University of Notre Dame; Paul Szejner, National Autonomous University of Mexico; Masahito Ueyama, Osaka Prefecture University; Danielle Ulrich, Montana State University; Caroline Vincke, Universit. Catholique de Louvain; Steven L. Voelker, Michigan Technological University and Jingshu Wei, Polish Academy of Sciences.

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JOURNAL

Science

DOI

10.1126/science.abm4875 

METHOD OF RESEARCH

Meta-analysis

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

Cross-biome synthesis of source versus sink limits to tree growth

ARTICLE PUBLICATION DATE

13-May-2022

Forests’ ability to sequester carbon depends on more than just photosynthesis; may become more limited

Peer-Reviewed Publication

AMERICAN ASSOCIATION FOR THE ADVANCEMENT OF SCIENCE (AAAS)

Photosynthesis and tree growth respond differently to different climate cues, according to a new study, suggesting that current forest carbon sequestration models may be overestimating forests’ ability to store atmospheric carbon. The findings illustrate the importance of considering processes other than photosynthesis for estimating how much carbon trees can sequester. Through photosynthesis, forests capture and sequester atmospheric carbon as woody biomass and soil carbon. Currently, this process offsets roughly 25% of annual anthropogenic carbon emissions. With elevated atmospheric carbon dioxide (CO2) boosting photosynthesis through a phenomenon known as carbon fertilization, using forests to sequester carbon is often viewed as an attractive natural solution to mitigating climate change. It's been assumed that photosynthesis and plant growth are generally limited by the amount of atmospheric carbon – more carbon, more growth, more storage. However, a growing body of research has indicated that this might not be the case, suggesting that forest carbon storage is sensitive to other factors, including temperature, water, and nutrient availability. This means forest carbon sequestration represents a source of major uncertainty for projections of global forests’ carbon storage potential. To better understand forest carbon uptake and its relationship to woody growth, Antoine Cabon and colleagues used estimates of the amount of carbon taken up by plants during photosynthesis from 78 forests worldwide and compared them to tree-ring growth data from the Tree-Ring Data Bank. Cabon et al. found a strong decoupling between photosynthesis (productivity) and plant growth, with substantial variation based on tree species, ecosystem traits, and climate conditions, indicating that the relationship between the two isn’t as linear as has been assumed. The findings highlight limits to tree growth, particularly in cold and dry areas, which may continue to constrain the carbon storage potential of forests under ongoing climate change. “The results reported by Cabon et al. have implications for using natural ecosystems to sequester carbon and for the success of natural climate solutions, such as planting trees, in combating climate change,” write Julia Green and Trevor Keenan in a related Perspective.

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JOURNAL

Science

DOI

10.1126/science.abm4875 

ARTICLE TITLE

Cross-biome synthesis of source versus sink limits to tree growth

ARTICLE PUBLICATION DATE

13-May-2022

Study sheds light on what influences water supplied by snowmelt

University of Nevada, Reno leads study looking at over 500 locations in the U.S.

Peer-Reviewed Publication

UNIVERSITY OF NEVADA, RENO

 

IMAGE: SNOW AND GLACIAL MELT FROM THE WIND RIVER MOUNTAINS IN WYOMING FEEDS THE WIND RIVER VIA DINWOODY CREEK. view more 

CREDIT: BEATRICE GORDON, UNIVERSITY OF NEVADA, RENO

RENO, Nev. – Water often falls from the sky and is stored in mountains across the U.S. as snow before it melts and flows down to urban and rural communities. Knowing what factors influence when and how much of that snowmelt ultimately makes it to streams, rivers and reservoirs is crucial for water managers trying to make the most of limited water resources. A new study led by researchers at University of Nevada, Reno and the Desert Research Institute (DRI) published in Environmental Research Letters identifies three major factors that influence snowmelt-driven water supplies and identifies regions where mountain water supplies respond differently to climate change. The study used data from 537 watersheds across the U.S.

Relying on 30-plus years of previous research compiled over more than two years, the research found that three factors – how much of the total winter snowfall is available at the end of the winter, how fast snow melts, and when snow melts – can be used to better predict how climate change will impact critical snowmelt-driven water supplies. And, the research team found major differences in how much each of these factors influence different watersheds throughout the country.

“Particularly in the Western U.S, snow is really the backbone of our water supply systems,” said Beatrice Gordon, the lead author and a doctoral student in the University of Nevada, Reno Graduate Program of Hydrologic Sciences and the Department of Natural Resources & Environmental Science. “But what’s challenging is that mountain water supplies respond differently to changes in snow depending on where you are in the U.S. Given that challenge, our goal was to provide other scientists and water managers with a simple, but powerful framework that can be used to improve predictions about the timing and amount of streamflow as climate change accelerates.”

Taking inventory

The first step in constructing this framework was to take inventory of what was known, and perhaps more importantly, what was not known, about how snow shapes streamflow. To do this, the researchers from University of Nevada, Reno and DRI teamed up with researchers at the University of Utah, Boise State University and Universidad de Concepción in Chile to review over three decades of previous research. This review included over 150 studies about snow and streamflow from around the world. Based on this synthesis, they found that the amount of streamflow, and to a lesser extent when spring streamflow occurs, varies in response to changes in snow across the U.S.

“It seems like we should have very accurate systems to forecast mountain water supplies, but the dirty secret is that there is a lot of uncertainty caused by climate change and changes in snowpack,” said researcher and co-author Adrian Harpold, associate professor at the University of Nevada, Reno and head of the University’s Nevada Mountain Ecohydrology Lab. As part of the University’s Experiment Station, which is a unit of the College of Agriculture, Biotechnology & Natural Resources, the lab conducts field and remote sensing observations, as well as modeling, to help answer some of the most pressing questions related to mountain ecohydrology in the face of changing environmental conditions.

The lack of certainty around when and how much water will come from winter snowpacks is a serious issue for water managers tasked with meeting the needs of a growing population and increased demands for food. Particularly in the Western U.S., which is characterized by wetter winters and drier summers, the majority of surface water originates as snowfall in the mountains, with more than two-thirds of reservoir inflows coming from snow. For context, roughly 40 million people, and much of the most agriculturally productive land in the Western U.S., rely at least partially on snowmelt-derived streamflow stored in two of these reservoirs.

“In the best of times, water managers throughout Western North America have a challenging job of ensuring a reliable water supply to agricultural, urban and recreational users,” said co-author Paul Brooks, a professor at the University of Utah. “They’ve done such a good job that many residents rarely give a second thought to their own water use. Increasingly, these managers are stuck between a rock and a hard place, as climate change and population growth are increasing water demand, while the amount and timing of water availability become more variable.”

A framework to navigate uncharted waters

The researchers’ review highlighted the grand challenge of managing mountain water supplies given all the uncertainty and variability in regional responses to climate change. Drawing upon their literature review and decades of experience from senior researchers, the authors developed a simple framework, centered around three factors, designed to help water managers better navigate the challenges posed by a more complex and uncertain future.

• Snow season water vapor fluxes. Despite the complicated name, the function of this mechanism is straightforward. It controls how much snow is available at the end of winter. Throughout the winter, water stored in snowpacks is “lost” to the atmosphere via evaporation (when water turns into a gas) and via sublimation (when snow turns into a gas). As winters get warmer, these losses are likely to increase, which the research illustrates can reduce the amount of snow available to be released as streamflow.
• Intensity of liquid water inputs. This mechanism concerns how fast water from snowmelt and/or rain reaches the ground. The rate at which precipitation reaches the ground surface impacts where water ultimately goes. Warmer winters mean more intense winter rainfall, which the research shows can lead to more streamflow.
• Synchrony between water and energy inputs. This mechanism deals with when water from snowmelt and/or rain is available in relation to when we need it most. Unlike rain, snow stays on the ground after it falls, acting as a large temporary (and free) reservoir for cities and farms. Snowpacks have historically released water into streams in the late spring and early summer, when demand for water is higher. Less snow means less storage, which the research shows will increase the gap between when water is supplied and when it is most needed.

Using publicly available data from the 537 sites across the U.S., the researchers then used this framework to determine where each of these factors are most and least important. The relative importance of these mechanisms for mountain water supplies, which the authors summarize as “how much, how fast, and when,” vary geographically, based on the study’s results.

Streamflow in the Great Basin, for example, is particularly sensitive to changes in all three of the mechanisms, making water management predictions an acute challenge in this region. However, nearby, on the other side of Donner Pass in the Sierra Nevada mountains, the research shows that how fast water reaches the ground surface and when water is available will be more important than how much snow is lost to the atmosphere via evaporation and sublimation.

More work to do

The framework is only the first step toward answering big questions about the fate of water supplies for the team. Harpold and Gordon, along with Gabrielle Boisrame and Rosemary Carroll of DRI, are on a USDA-sponsored project, “SNOWPACs,” led by the University of Nevada, Reno, in a collaboration with other universities. 

“This study came out of a need to characterize variable changes in streamflow that are occurring in the Intermountain West and challenging reservoir management that are critical to agricultural water supplies,” Harpold said.

Complementing the USDA project, Brooks has been collaborating with the Salt Lake City Department of Public Utilities, Salt River Project, Weber Basin Water Conservancy District and other managers throughout the Western U.S. to identify and plan for changes in water supply in a warming climate.

The team is focusing its next efforts on understanding how these streamflow changes impact agriculturally dominated basins, including the Walker River Basin, which supplies water for agriculture in Nevada.

“As someone who grew up in agriculture in the Western U.S., I know how much snow matters to our farming and ranching communities,” Gordon said. “And I’m excited to see how the work coming out of SNOWPACs provides critical information to decision-makers who are currently grappling with these changes in our mountain water supplies.”

Support for the research recently published in Environmental Research Letters was provided the USDA NIFA (Project # NEVW-2017-08812) and the Lincoln Institute's Babbitt Dissertation Fellowship Program.

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JOURNAL

Environmental Research Letters

DOI

10.1088/1748-9326/ac64b4 

METHOD OF RESEARCH

Data/statistical analysis

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

Why does snowmelt-driven streamflow response to warming vary? A data-driven review and predictive framework

Hunga volcano eruption provides an explosion of data

Peer-Reviewed Publication

UNIVERSITY OF ALASKA FAIRBANKS

The massive Jan. 15, 2022, eruption of the Hunga submarine volcano in the South Pacific Ocean created a variety of atmospheric wave types, including booms heard 6,200 miles away in Alaska. It also created an atmospheric pulse that caused an unusual tsunami-like disturbance that arrived at Pacific shores sooner than the actual tsunami.

Those are among the many observations reported by a team of 76 scientists from 17 nations that researched the eruption’s atmospheric waves, the largest known from a volcano since the 1883 Krakatau eruption. The team’s work, compiled in an unusually short amount of time due to significant scientific interest in the eruption, was published today in the journal Science.

David Fee, director of the Wilson Alaska Technical Center at the University of Alaska Fairbanks Geophysical Institute, is a leading author of the research paper and among four of the center's researchers involved in the work.

The Hunga eruption, near the island of Tonga, has provided unprecedented insight into the behavior of some atmospheric waves. A dense network of barometers, infrasound sensors and seismometers in Alaska — operated by the Geophysical Institute’s Wilson Alaska Technical Center, Alaska Volcano Observatory and Alaska Earthquake Center — contributed to the data.

“Our hope is that we will be better able to monitor volcanic eruptions and tsunamis by understanding the atmospheric waves from this eruption,” said Fee, who is also the coordinating scientist at the Geophysical Institute’s portion of the Alaska Volcano Observatory.

“The atmospheric waves were recorded globally across a wide frequency band, and by studying this remarkable dataset we will better understand acoustic and atmospheric wave generation, propagation and recording,” he said. “This has implications for monitoring nuclear explosions, volcanoes, earthquakes and a variety of other phenomena.”

The researchers found particularly interesting the behavior of the eruption’s Lamb wave, a type named for its 1917 discoverer, English mathematician Horace Lamb.

The largest atmospheric explosions, such as from volcanic eruptions and nuclear tests, create Lamb waves. They can last from minutes to several hours.

A Lamb wave is a type of guided wave, those that travel parallel along a material’s surface and also extend upward. With the Hunga eruption, the wave traveled along Earth’s surface and circled the planet in one direction four times and in the opposite direction three times — the same as observed in the 1883 Krakatau eruption.

“Lamb waves are rare. We have very few high-quality observations of them,” Fee said. “By understanding the Lamb wave, we can better understand the source and eruption. It is linked to the tsunami and volcanic plume generation and is also likely related to the higher-frequency infrasound and acoustic waves from the eruption.”

The Lamb wave consisted of at least two pulses near Hunga, with the first having a seven- to 10-minute pressure increase followed by a second and larger compression and subsequent long pressure decrease.

The wave also reached into Earth’s ionosphere, rising at 700 mph to an altitude of about 280 miles, according to data from ground-based stations.

A major difference with the Hunga explosion’s Lamb wave compared to the 1883 wave is the amount of data gathered due to more than a century of advancement in technology and a proliferation of sensors around the globe, according to the paper. 

Scientists noted other findings about atmospheric waves associated with the eruption, including “remarkable” long-range infrasound — sounds too low in frequency to be heard by humans. Infrasound arrived after the Lamb wave and was followed by audible sounds in some regions. 

Audible sounds, the paper notes, traveled about 6,200 miles to Alaska, where they were heard around the state as repeated booms about nine hours after the eruption. 

“I heard the sounds but at the time definitely did not think it was from a volcanic eruption in the South Pacific,” Fee said.

The Alaska reports are the farthest documented accounts of audible sound from its source. That is due in part, the paper notes, to global population increases and advances in societal connectivity.

“We will be studying these signals for years to learn how the atmospheric waves were generated and how they propagated so well across Earth,” Fee said.

Other Geophysical Institute scientists involved in the research include graduate student Liam Toney, acoustic wave analysis, figure and animation production; postdoctoral researcher Alex Witsil, acoustic wave analysis and equivalent explosive yield analysis; and seismo-acoustic researcher Kenneth A. Macpherson, sensor response and data quality. All are with the Wilson Alaska Technical Center.

The Alaska Volcano Observatory, National Science Foundation and U.S. Defense Threat Reduction Agency funded the UAF portion of the research.

Robin S. Matoza of the University of California, Santa Barbara, is the paper’s lead author.

ADDITIONAL CONTACT: David Fee, 907-474-7564, dfee1@alaska.edu.

NOTE TO EDITORS: Photographs are available at the Geophysical Institute website. The research paper is available here.

 

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JOURNAL

Science

DOI

10.1126/science.abo7063 

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

Atmospheric waves and global seismoacoustic observations of the January 2022 Hunga eruption, Tonga

ARTICLE PUBLICATION DATE

12-May-2022

*Free* A close-up of the 2022 volcanic eruption that sent waves around the world

Peer-Reviewed Publication

AMERICAN ASSOCIATION FOR THE ADVANCEMENT OF SCIENCE (AAAS)

Observations from two studies of the January 2022 volcanic eruption of Hunga volcano, Tonga, show a complex main event that was as energetic as the 1883 Krakatau eruption, one of the deadliest and most destructive volcanic events in recorded history. The observations also uncover that the tsunami generated by this eruption was partially driven by an unexpected atmospheric wave. This set of observations will be helpful for disentangling the event and understanding the propagation of waves through the atmosphere and ocean. On 15 January, 2022, a massive volcanic eruption occurred on a small, uninhabited island in the South Pacific, Hunga Tonga-Hunga Ha‘apai. The Hunga Tonga eruption was one of the most powerful recorded, with audible sound detected over 10,000 kilometers from the source. In one study, Robin Matoza et al. present infrasound and seismic recordings, along with other geophysical observations, that characterize this event. An atmospheric Lamb wave, characteristic of energetic atmospheric events, circled the planet four times and was similar to the 1883 Krakatau eruption. The eruption also generated long range infrasounds and ionospheric interations, along with global tsunamis. In a second study focused on the tsunamis, first waves from which arrived more than 2 hours earlier than expected for conventional tsunamis, Tatsuya Kubota and colleagues investigated the generation and propagation mechanisms of the tsunami “forerunner.” Typically, tsunamis generated by volcanic eruptions are created by water displacement from deformation and atmospheric pressure waves that travel at about the same velocity as the tsunami. Kubota et al. found that for the Hunga Tonga eruption, a different sort of atmospheric pressure wave – a Lamb wave – also contributed to tsunami propagations. This interaction resulted in tsunami waves arriving much earlier than expected. Future tsunami models should incorporate this phenomenon, the authors say.

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JOURNAL

Science

DOI

10.1126/science.abo7063 

ARTICLE TITLE

Atmospheric waves and global seismoacoustic observations of the January 2022 Hunga eruption, Tonga

ARTICLE PUBLICATION DATE

12-May-2022

Eruption’s echoes

Massive eruption of Tongan volcano provides an explosion of data on atmospheric waves

Peer-Reviewed Publication

UNIVERSITY OF CALIFORNIA - SANTA BARBARA

The Hunga volcano ushered in 2022 with a bang, devastating the island nation of Tonga and sending aid agencies, and Earth scientists, into a flurry of activity. It had been nearly 140 years since an eruption of this scale shook the Earth.

UC Santa Barbara’s Robin Matoza led a team of 76 scientists, from 17 nations, to characterize the eruption’s atmospheric waves, the strongest recorded from a volcano since the 1883 Krakatau eruption. The team’s work, compiled in an unusually short amount of time, details the size of the waves originating from the eruption, which the authors found were on par with those from Krakatau. The data also provides exceptional resolution of the evolving wavefield compared to what was available from the historic event.

The paper, published in the journal Science, is the first comprehensive account of the eruption’s atmospheric waves.

Early evidence suggests that an eruption Jan. 14 sunk the volcano’s main vent below sea level, priming the massive explosion the following day. The Jan. 15 eruption generated a variety of different atmospheric waves, including booms heard 6,200 miles away in Alaska. It also created a pulse that caused the unusual occurrence of a tsunami-like disturbance an hour before the actual seismically driven tsunami began.

“This atmospheric waves event was unprecedented in the modern geophysical record,” said lead author Matoza, an associate professor at UC Santa Barbara’s Department of Earth Science.

The Hunga volcanic eruption has provided unprecedented insight into the behavior of a variety of atmospheric wave types. “The atmospheric waves were recorded globally across a wide frequency band,” said co-author David Fee at the University of Alaska Fairbanks Geophysical Institute. “And by studying this remarkable dataset we will better understand acoustic and atmospheric wave generation, propagation and recording.

“This has implications for monitoring nuclear explosions, volcanoes, earthquakes and a variety of other phenomena,” Fee continued. “Our hope is that we will be better able to monitor volcanic eruptions and tsunamis by understanding the atmospheric waves from this eruption.”

The researchers were most interested in the behavior of an atmospheric wave known as a Lamb wave, which is the dominant pressure wave produced by the eruption. These are longitudinal pressure waves, much like sound waves, but of particularly low frequency. Such  low frequency, in fact, that the effects of gravity must be taken into account. Lamb waves are associated with the largest atmospheric explosions, such as large eruptions and nuclear detonations, though the wave characteristics differ between these two sources. They can last from minutes to several hours.

After the eruption, the waves traveled along Earth’s surface and circled the planet in one direction four times and in the opposite direction three times, the authors recorded. This was the same as scientists observed in the 1883 Krakatau eruption. The Lamb wave also reached into Earth’s ionosphere, rising at 700 mph to an altitude of about 280 miles.

“Lamb waves are rare. We have very few high-quality observations of them,” Fee said. “By understanding the Lamb wave, we can better understand the source and eruption. It is linked to the tsunami and volcanic plume generation and is also likely related to the higher-frequency infrasound and acoustic waves from the eruption.”

The Lamb wave consisted of at least two pulses near the volcano. The first had a seven- to 10-minute pressure increase followed by a second and larger compression and subsequent long pressure decrease.

A major difference between the accounts of Hunga’s Lamb waves versus Krakatau’s is the amount and quality of data scientists were able to gather. “We have more than a century of advances in instrumentation technology and global sensor density,” Matoza said. “So the 2022 Hunga event provided an unparalleled global dataset for an explosion event of this size.”

Scientists noted other findings about atmospheric waves associated with the eruption, including remarkable long-range infrasound — sounds too low in frequency to be heard by humans. Infrasound arrived after the Lamb wave and was followed by audible sounds in some regions.

Audible sounds reached Alaska, about 6,200 miles from the volcano, where they were heard around the state as repeated booms. “I heard the sounds,” Fee recalled, “but at the time definitely did not think it was from a volcanic eruption in the South Pacific.”

The scientists believe the sounds heard in Alaska couldn’t have originated in Hunga. While there’s still much to learn, it’s clear that standard sound models cannot explain how audible sounds propagated over such extreme distances. “We interpreted that they were generated somewhere along the path by nonlinear effects,” Matoza explained.

“There is a long list of possible follow-up studies examining the many different aspects of these signals in more detail,” he said. “As a community, we will be working further on this event for years.”

(This release was co-authored by Rod Boyce at University of Alaska Fairbanks’

Geophysical Institute)

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JOURNAL

Science

DOI

10.1126/science.abo7063 

ARTICLE TITLE

Atmospheric waves and global seismoacoustic observations of the January 2022 Hunga eruption, Tonga

ARTICLE PUBLICATION DATE

12-May-2022

Major study to examine beavers’ Arctic impact

Anglia Ruskin University receives £553K of funding to lead important research project in Canada

Grant and Award Announcement

ANGLIA RUSKIN UNIVERSITY

 

IMAGE: NORTH AMERICAN BEAVER (CASTOR CANADENSIS) - PHOTO BY DR HELEN WHEELER view more 

CREDIT: PHOTO BY DR HELEN WHEELER OF ANGLIA RUSKIN UNIVERSITY

Anglia Ruskin University (ARU) in Cambridge, England, has received funding of over half a million pounds to lead a major new study to investigate the impact of beavers as they spread northwards into the Arctic.

The North American beaver (Castor canadensis) has been expanding its range in recent decades and this important research aims to understand the effects that beavers are having on the Arctic landscape, on other animals, and on local Indigenous communities.

The UK part of the three-year project is being led by Principal Investigator Dr Helen Wheeler and will build on research currently being carried out by ARU in the Gwich'in Settlement Region in Canada’s Northwest Territories, examining how beavers are changing local ecosystems.

The new study, which begins this month, will focus on an area even further north, in Canada’s Inuvialuit Settlement Region.  ARU has received £553,491 from UK Research and Innovation (UKRI) and will be working alongside Wilfrid Laurier University of Canada and the Inuvialuit Fisheries Joint Management Committee. ARU’s Canadian partners are being funded by Polar Knowledge Canada and Fonds de recherche du Québec, and Professor Philip Marsh of Wilfrid Laurier University is the Principal Investigator for the Canadian partners.

A key question for the Inuvialuit Settlement Region, and beyond, is the extent, scope and interlinkages between ecological and sociological changes that take place as beaver numbers increase. The impact of beavers can cascade down ecological systems, causing major transformations known as regime shifts.

Through dam building, beavers are capable of changing landscapes by creating ponds and diverting rivers, leading to a reduction in fish populations that are relied upon by local communities.

As beaver numbers increase north of the treeline and into the Arctic, ponds created by beavers are also causing permafrost to melt, which can lead to the release of the greenhouse gases methane and carbon dioxide.

In collaboration with the Inuvialuit Fisheries Joint Management Committee, this new project will examine precisely how the presence of beavers affects stream and lake characteristics, fish populations, and local communities.

Dr Helen Wheeler, Senior Lecturer in Zoology at Anglia Ruskin University (ARU), said: “We are delighted to receive this funding from UK Research and Innovation as this project will allow us to work closely with the Inuvialuit Fisheries Joint Management Committee and members of the Inuvialuit community to address an important environmental change that is causing a great deal of concern in the area.

“Thanks to the scale of the project and the funding we have received, we will be able to investigate the complex effects of rapid environmental change in a truly interdisciplinary way, bringing together experts in wildlife change, hydrology, biogeochemistry, ecosystem and fish ecology, and human wellbeing, and I’m really looking forward to carrying out fieldwork in the region this summer.

“What is especially pleasing is that this project is working closely with Inuvialuit partners and community members, and together we will be creating tools and infrastructure that will exist way beyond the life of the project. This will allow locally led monitoring and research to continue in the region long term, providing the Inuvialuit with the scientific data on the changes created by beavers that is necessary to help inform their ongoing stewardship of the land.”

Ends

As drug overdose deaths climb, experts assess strategies to stem the tide

Innovators from across the nation gather to evaluate stigma, health equity as barriers to substance use disorder care

Meeting Announcement

UNIVERSITY OF ROCHESTER MEDICAL CENTER

Stemming the tide of the opioid crisis in rural communities requires taking action to overcome the stigma and health inequity that have increased barriers to recovery from substance use disorder (SUD). It also takes a diverse group of people with profound knowledge of the issues and dedication to finding solutions.

The University of Rochester Recovery Center of Excellence is bringing many of these champions together. People with lived experience of SUD, artists, authors, providers, researchers, policymakers, and advocates who share a focus on health equity related to SUD will gather to share perspectives and strategies at the Eastman School of Music in Rochester, NY, May 18–20.

“For many years, our country has looked at substance use disorder as a disease of the weak-minded; something that happens to other people with a history of ‘bad behavior’ that had this coming to them. We isolate those ‘bad’ people, lest their behavior is catchy. That is stigma,” said Michele Lawrence, M.B.A., M.P.H, assistant professor of Psychiatry and Public Health Sciences at the University of Rochester Medical Center and co-principal investigator of the UR Recovery Center of Excellence. “The only way we can improve the treatment of substance use disorder is to recognize and understand how stigma and inequity act as obstacles to change.”

The Taking Action: National Rural Substance Use Disorder Health Equity and Stigma Summit will feature keynote speakers from across the country, including: Uché Blackstock, M.D., whose organization Advancing Health Equity is working to dismantle racism in health care; Beth Macy, author of the best-selling book Dopesick (now a Hulu series); Sam Quinones, author of the award-winning book Dreamland and The Least of Us; Leonard Buschel, director of the REEL Recovery Film Festival; Tony Hoffman, former BMX Elite Pro and Olympic coach; and Peter Gaumond and Robert Kent of the White House Office of National Drug Control Policy.

“At a time when fatalities from the overdose crisis have reached record numbers, this summit brings together people who have the tools to bring about change,” said Gloria J. Baciewicz, M.D., professor in the Department of Psychiatry at URMC and co-principal investigator of the UR Recovery Center of Excellence. “These discussions are particularly important as we face the ‘fourth wave’ of the opioid epidemic, which is being driven by the use of deadly synthetic opioids, stimulants, and the use of multiple substances in combination.”

The reality of the treatment landscape in many rural communities – limited resources, few providers, and a lack of anonymity – coupled with stigma and health inequities creates substantial roadblocks for those seeking SUD/opioid use disorder care. According to Lawrence, “This conference is the start of a conversation about how we, as a society, work our way out of this. It starts with connection to each other and listening to each other’s stories so we can see the humanity and similarities in people who may look different than us. It starts with facing up to the stigma we all carry and realizing that all of us have flaws, but we are better together than alone.”

Under a grant from the Health Resources and Services Administration (HRSA) totaling $12.3 million, the University of Rochester Recovery Center of Excellence has been disseminating best practices to reduce morbidity and mortality related to SUD, with particular focus on synthetic opioids, to rural Appalachian communities that have been hit hard by the opioid crisis.

Since being established in fall 2019, the center has disseminated 12 best practices that have been adapted for implementation in rural communities. Recent initiatives include suicide prevention training, resources to reduce overdose from combined substances, and training on treatment of SUD in primary care. Another of the center’s projects is a campaign to reduce stigma through art and community conversations.

The center is also implementing a model in rural Appalachian New York called the Ecosystem of Recovery, which creates broader access to and community-wide support for best practices in opioid use disorder treatment. One of three Rural Centers of Excellence on Substance Use Disorders funded by HRSA, UR Recovery Center of Excellence provides organizations in rural communities with program assistance as they work through planning and implementation challenges.

Registration to this hybrid summit is free of cost and is open to the public. In-person attendance is limited. Continuing education credits will be offered.

 

This HRSA RCORP RCOE program is supported by the Health Resources & Services Administration (HRSA) of the US Department of Health & Human Services (HHS) as part of an award totaling $12.3M with 0% financed with non-governmental sources.

The contents are those of the author(s) and do not necessarily represent the official views of, nor an endorsement by HRSA, HHS or the US Government.

Vegetables that thwart pollutants

Celery, carrots, parsnips and parsley can take on toxins from cigarette smoke and air pollution

UNIVERSITY OF DELAWARE
ARTICLE HIGHLIGHT | 12-MAY-2022

image: Jae Kyeom Kim, assistant professor of behavioral health and nutrition at the University of Delaware, discusses analyses of vegetable diet interventions with a graduate research assistant. view more
Credit: University of Delaware/ Ashley Barnas

A University of Delaware researcher has discovered a way to mitigate the effect of air pollutants in our bodies by increasing daily intake of vegetables such as celery, carrots, parsnips, and parsley.

In a new article published in The Journal of Nutritional Biochemistry, Jae Kyeom Kim, assistant professor of behavioral health and nutrition, investigates how these vegetables from the apiaceous family protect the body from accumulation of acrolein, an irritant to the lungs and skin with a strong unpleasant odor, abundantly found in cigarette smoke and automobile exhaust.

Through a series of tests, Kim and his team analyzed how apiaceous vegetables, which are high in phytonutrients, mitigated acrolein-induced toxicities. The results portrayed how oxidative stress, triggered by acrolein, can be reduced and its impacts mitigated.

“Kim’s research discovered that apiaceous vegetables supported detoxification through an increase in antioxidant enzyme activity,” Trabulsi said. “The results suggest that apiaceous vegetables may provide protection against acrolein-induced damages and inflammation because in the liver, the vegetables enhance conversion of acrolein into a water-soluble acid for bodily excretion.”

The next step was to determine a reasonable dosage amount for humans. Looking forward, Kim plans to integrate human intervention trials.

“When we calculated this, we determined the actual daily calorie amount of apiaceous vegetables for humans is roughly 1 and 1/3 cups per day,” Kim said. “It doesn’t require a high intake to see a difference, and this is an achievable amount in daily life.”

Kim and his team stress the importance of implementing behavioral changes in diet as a solution to combat the buildup of toxicants derived from air pollution.

“Research has identified that it is the totality of nutrients in fruits and vegetables that support beneficial health outcomes, rather than a single nutrient,” Trabulsi said. “Focusing on a healthy whole food diet is more impactful than relying on individual supplements.”