Saturday, June 05, 2021

Fungus creates a fast track for carbon

Stanford scientists find epidemics of fungal infections in algae alter carbon cycling

STANFORD'S SCHOOL OF EARTH, ENERGY & ENVIRONMENTAL SCIENCES

IMAGE: FUNGUS CREATES AN UNDERAPPRECIATED EXPRESS LANE FOR CARBON, "SHUNTING " AS MUCH AS 20 PERCENT OF THE CARBON FIXED BY DIATOMS OUT OF THE MICROBIAL LOOP AND INTO THE FUNGAL PARASITE. view more
CREDIT: KLAWONN ET AL. 2021, PNAS

Tiny algae in Earth's oceans and lakes take in sunlight and carbon dioxide and turn them into sugars that sustain the rest of the aquatic food web, gobbling up about as much carbon as all the world's trees and plants combined.

New research shows a crucial piece has been missing from the conventional explanation for what happens between this first "fixing" of CO2 into phytoplankton and its eventual release to the atmosphere or descent to depths where it no longer contributes to global warming. The missing piece? Fungus.

"Basically, carbon moves up the food chain in aquatic environments differently than we commonly think it does," said Anne Dekas, an assistant professor of Earth system science at Stanford University. Dekas is the senior author of a paper published June 1 in Proceedings of the National Academy of Sciences that quantifies how much carbon goes into parasitic fungi that attack microalgae.

Underwater merry-go-round

Researchers until now have predicted that most carbon fixed into colonies of hard-shelled, single-celled algae known as diatoms then funnels directly into bacteria - or dissolves like tea in the surrounding water, where it's largely taken up by other bacteria. Conventional thinking assumes carbon escapes from this microbial loop mainly through larger organisms that graze on the bacteria or diatoms, or through the CO2 that returns to the atmosphere as the microbes breathe.

This journey is important in the context of climate change. "For carbon sequestration to occur, carbon from CO2 needs to go up the food chain into big enough pieces of biomass that it can sink down into the bottom of the ocean," Dekas said. "That's how it's really removed from the atmosphere. If it just cycles for long periods in the surface of the ocean, it can be released back to the air as CO2."

It turns out fungus creates an underappreciated express lane for carbon, "shunting" as much as 20 percent of the carbon fixed by diatoms out of the microbial loop and into the fungal parasite. "Instead of going through this merry-go-round, where the carbon could eventually go back to the atmosphere, you have a more direct route to the higher levels in the food web," Dekas said.

The findings also have implications for industrial and recreational settings that deal with harmful algal blooms. "In aquaculture, in order to keep the primary crop, like fish, healthy, fungicides might be added to the water," Dekas said. That will prevent fungal infection of the fish, but it may also eliminate a natural check on algal blooms that cost the industry some $8 billion per year. "Until we understand the dynamics between these organisms, we need to be pretty careful about the management policies we're using."

Microbial interactions

The authors based their estimates on experiments with populations of chytrid fungi called Rhizophydiales and their host, a type of freshwater algae or diatom named Asterionella formosa. Coauthors in Germany worked to isolate these microbes, as well as bacteria found in and around their cells, from water collected from Lake Stechlin, about 60 miles north of Berlin.

"Isolating one microorganism from nature and growing it in the laboratory is difficult, but isolating and maintaining two microorganisms as a pathosystem, in which one kills the other, is a true challenge," said lead author Isabell Klawonn, who worked on the research as a postdoctoral scholar in Dekas' lab at Stanford. "Only a few model systems are therefore available to research such parasitic interactions."

Scientists surmised as early as the 1940s that parasites played an important role in controlling the abundance of phytoplankton, and they observed epidemics of chytrid fungus infecting Asterionella blooms in lake water. Technological advances have made it possible to pick apart these invisible worlds in fine and measurable detail - and begin to see their influence in a much bigger picture.

"We're realizing as a community that it's not just the capabilities of an individual microorganism that's important for understanding what happens in the environment. It's how these microorganisms interact," Dekas said.

The authors measured and analyzed interactions within the Lake Stechlin pathosystem using genomic sequencing; a fluorescence microscopy technique that involves attaching fluorescent dye to RNA within microbial cells; and a highly specialized instrument at Stanford - one of only a few dozen in the world - called NanoSIMS, which creates nanoscale maps of the isotopes of elements that are present in materials in vanishingly small amounts. Dekas said, "To get these single-cell measurements to show how photosynthetic carbon is flowing between specific cells, from the diatom to the fungus to the associated bacteria, it's the only way to do it."

The exact amount of carbon diverted to fungus from the microbial merry-go-round may differ in other environments. But the discovery that it can be as high as 20 percent in even one setting is significant, Dekas said. "If you're changing this system by more than a few percent in any direction, it can have dramatic implications for biogeochemical cycling. It makes a big difference for our climate."

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Stanford coauthors include Alma E. Parada and Nestor Arandia-Gorostidi, postdoctoral research fellows in the Department of Earth System Science at the School of Earth, Energy & Environmental Sciences (Stanford Earth). Additional coauthors are affiliated with Leibniz-Institute of Freshwater Ecology and Inland Fisheries, the Swedish Museum of Natural History and Potsdam University. Klawonn is now affiliated with Leibniz Institute for Baltic Sea Research.

The research was supported by the German Academic Exchange Service, the Simons Foundation and the German Research Foundation.

Why scientists want to solve an underground mystery about where microbes live

BU researchers develop first-of-its-kind model to predict which species of soil organisms live in different environments, with huge implications for agriculture, climate change, and public health

BOSTON UNIVERSITY

Research News

Though it might seem inanimate, the soil under our feet is very much alive. It's filled with countless microorganisms actively breaking down organic matter, like fallen leaves and plants, and performing a host of other functions that maintain the natural balance of carbon and nutrients stored in the ground beneath us.

"Soil is mostly microorganisms, both alive and dead," says Jennifer Bhatnagar, soil microbiologist and Boston University College of Arts & Sciences assistant professor of biology. It's typical to see several hundred different types of fungi and bacteria in a single pinch of soil off the ground, she says, making it one of the most diverse ecosystems that exist.

Because there's still so much unknown about soil organisms, until now scientists have not attempted to predict where certain species or groups of soil microbes live around the world. But having that knowledge about these organisms-- too small to see with the naked eye--is key to better understanding the soil microbiome, which is made up of the communities of different microbes that live together.

A team of BU biologists, including Bhatnagar, took on that challenge--and their research reveals, for the first time, that it is possible to accurately predict the abundance of different species of soil microbes in different parts of the world. The team recently published their findings in a new paper in Nature Ecology & Evolution.

"If we know where organisms are on earth, and we know how they change through space and time due to different environmental forces, and something about what different species are doing, then we can much better predict how the function of these communities will change in terms of carbon and nutrient cycling," Bhatnagar says. That kind of knowledge would have huge implications for agriculture, climate change, and public health.

"The health of the soils is so tied to the soil microbes," says Michael Dietze, senior author on the study and a BU College of Arts & Sciences professor of earth and environment. Dietze, Bhatnagar, and researchers from their labs joined forces to work on this project, which involved analyzing hundreds of soil samples collected by National Ecological Observatory Network (NEON) research sites. Bhatnagar and her lab members brought to the team their soil expertise, while Dietze and his lab offered their unique ability to develop precise ecological forecasts and near-term environmental predictions.

The team learned that microbe predictability increases as spatial area increases, so the bigger the piece of land their model makes forecasts about, the more likely the predictions about what types of microbes live there will be accurate.

Dietze says the ability to accurately predict which microbes would likely be found in a given soil sample also increased as the researchers looked at organism groupings higher up on the phylogenetic scale, a system that classifies organisms based on evolutionary relatedness. On the smallest end of the scale, a "species" represents the finest level of classification; on the other end, a "phylum" makes up the largest and most diverse groupings of organisms. They were surprised to find that they were better able to predict the presence of a whole phylum, as opposed to individual species.

After receiving the genomic data of the soil samples from NEON, the research team's forecasting models take into account environmental factors specific to the place where the soil came from--what plants live there, the soil acidity (pH), temperature, climate, and many others. They found their model was best able to predict the presence of microorganisms based on their symbiotic relationship with local plant species. Mycorrhizal fungi, for example, is a very common soil microbe that about 90 percent of plant families associate with, including pines and oak trees in New England.

In contrast, the team found it was more difficult to predict large groups of organisms based on their relationship with soil acidity. Despite knowing soil acidity levels, and what types of bacteria would typically like to live in that environment, their model couldn't accurately predict the amount of bacteria that were actually present in the soil sample, Bhatnagar says. "That means there is something else beyond the relationship with [acidity], beyond the relationship with any other environmental factor that we typically measure in our ecosystems," she says.

Now, Dietze and Bhatnagar's team are expanding their forecasts beyond predicting microbes based on only their location, to also include specific times of the year.

"Building a framework for forecasting the soil microbiome at sites across the US will improve our understanding of seasonal and interannual change," says Zoey Werbin, a PhD student working in Bhatnagar's lab and an author on the paper. "This could help us anticipate how climate change could affect microbial processes like decomposition or nitrogen cycling."

With her dissertation project, Werbin hopes to answer fundamental questions about how and why the soil microbiome varies over time and space.

"The more we learn, the more we realize how important soil microbes are for agriculture, public health, and climate change. It's really exciting to investigate how microscopic organisms can have such large-scale effects," Werbin says. "We know certain factors, like temperature and moisture, affect microbial communities. But we don't know how important those factors are compared to natural variability, or interactions between microbes. My PhD project will help identify the driving forces of the soil microbiome, as well as the biggest sources of uncertainty."

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SLAS Discovery's June issue on synthetic biology available now

SLAS (SOCIETY FOR LABORATORY AUTOMATION AND SCREENING)

Research News

Oak Brook, IL - The June edition of SLAS Discovery features the cover article, "A Perspective on Synthetic Biology in Drug Discovery and Development--Current Impact and Future Opportunities" by Florian David, Ph.D. (Chalmers University of Technology, Gothenburg, Sweden), Andrew M. Davis, Ph.D. (AstraZeneca, Cambridge, England, UK). Michael Gossing, Ph.D., Martin A. Hayes, Ph.D., and Elvira Romero, Ph.D., and Louis H. Scott, Ph.D. (AstraZeneca, Gothenburg, Sweden), and Mark J. Wigglesworth, Ph.D. (AstraZeneca, London, England, UK).

In January 2021, a survey of immunologists, infectious-disease researchers and virologists found that 90% of respondents believe SARS-CoV-2 will become endemic, continuing to circulate in pockets of the global population for years to come. Even as vaccines are becoming more widely available, there are people who either do not respond to the treatment or are not suitable for vaccination. There is a critical need to develop small molecule inhibitors for this pathogen. The cover article highlights the work of the Drug Discovery Unit at the University of Dundee (Dundee, Scotland, UK) reporting on the development of a high-throughput biochemical assay to assess the impact of small molecules on the methyltransferase activity of SARS-CoV-2 nonstructural protein 14 (nsp14). This enzyme is responsible for the N7-methylation of the cap at the 5' end of viral RNA and is critical in helping coronaviruses evade host defenses. The label-free MS-based assay developed was used to screen a library of 1771 FDA-approved drugs. The chemical hits that were identified may serve as starting points for drug discovery programs aimed at delivering therapeutics for the SARS-CoV-2 virus.

The June issue of SLAS Discovery includes nine articles of original research.

These include:

Development and Validation of High-Content Analysis for Screening HDAC6-Selective Inhibitors
In Vitro Pharmacokinetic/Pharmacodynamic Modeling of HIV Latency Reversal by Novel HDAC Inhibitors Using an Automated Platform
Identification and Kinetic Characterization of Serum- and Glucocorticoid-Regulated Kinase Inhibitors Using a Fluorescence Polarization-Based Assay
Reducing False Positives through the Application of Fluorescence Lifetime Technology: A Comparative Study Using TYK2 Kinase as a Model System
Biochemical and Cellular Profile of NIK Inhibitors with Long Residence Times
A Novel High-Throughput FLIPR Tetra-Based Method for Capturing Highly Confluent Kinetic Data for Structure-Kinetic Relationship Guided Early Drug Discovery
A Multipronged Screening Approach Targeting Inhibition of ETV6 PNT Domain Polymerization
Unbiased High-Throughput Drug Combination Pilot Screening Identifies Synergistic Drug Combinations Effective against Patient-Derived and Drug-Resistant Melanoma Cell Lines
Regenerable Biosensors for Small-Molecule Kinetic Characterization Using SPR

Beyond synthetic biology, synthetic ecology boosts health by engineering the environment

BU scientists are investigating how environmental molecules can be used to engineer 'designer' microbiomes for combating disease, pollution, and more

BOSTON UNIVERSITY

Research News

IMAGE: IN A NEW NATURE COMMUNICATIONS STUDY, RESEARCHERS FROM BU'S MICROBIOME INITIATIVE DISCOVERED THAT PROVIDING MICROBIAL COMMUNITIES WITH A BROADER VARIETY OF FOOD SOURCES DIDN'T INCREASE THE VARIETY OF MICROBIAL SPECIES... view more
CREDIT: IMAGE COURTESY OF ALAN PACHECO AND DANIEL SEGRÈ.

There's a lot of interest right now in how different microbiomes--like the one made up of all the bacteria in our guts--could be harnessed to boost human health and cure disease. But Daniel Segrè has set his sights on a much more ambitious vision for how the microbiome could be manipulated for good: "To help sustain our planet, not just our own health."

Segrè, director of the Boston University Microbiome Initiative, says he and other scientists in his field of synthetic and systems biology are studying microbiomes--microscopic communities of bacteria, fungi, or a combination of those that exert influence over each other and the surrounding environment. They want to know how microbiomes might be directed to carry out important tasks like absorbing more atmospheric carbon, protecting coral reefs from ocean acidification, improving the fertility and yield of agricultural lands, and supporting the growth of forests and other plants despite changing environmental conditions.

"Microbes affect us as humans through their own metabolic processes, they affect our planet through what they consume and secrete, they help create the oxygen we breathe," says Segrè, a BU College of Arts & Sciences professor of biology and bioinformatics, and a College of Engineering professor of biomedical engineering. "A long time ago microbes are what made multicellular life possible."

But, unlike many other synthetic biologists who are working to enhance or genetically engineer microbes directly, Segrè is more interested in how to direct the behavior of a microbiome by tweaking the environmental conditions it lives within--an approach he says could be better described as "synthetic ecology."

"The more traditional synthetic biology approach would be to manipulate the genomes of the microbes," Segrè says. "But we're trying to manipulate microbial ecosystems using environmental molecules."

"We know that microbial interactions with the environment are important," says Alan Pacheco, who earned his PhD in bioinformatics working in Segrè's lab. Some of those interactions benefit several microbial species, some only benefit one species in a community, and some can be harmful to certain species, he says. "But there's still so much we don't know about why these interactions happen the way that they do."

In a new study recently published in Nature Communications, Segrè, Pacheco, and their collaborator Melisa Osborne, a research scientist in Segrè's lab, explored how the presence of 32 different environmental molecules or nutrients, alone or in combination with others, would influence the growth rate of microbial communities and the mix of diverse species making up a given microbiome.

"In the back of our minds we had this idea of diet, framed by studies that have looked at differences in the gut microbiome based on Western vs hunter-gatherer diets," says Pacheco, who is now a postdoctoral fellow at ETH Zürich. Hunter-gatherer diets, opportunistic and comprising a wide range of plant-based food sources, are considered much more diverse than the Western diet, which is why the hunter-gatherer diet is thought to cultivate a healthier gut.

But the experimental results surprised the team. They expected they would see growth and diversity of microbiomes increase as the "bugs" had more access to a variety of foods--a range of carbons, including sugars, amino acids, and complex polymers--but that's not what their carefully controlled experiments revealed. Instead, they observed that competition for food between different species of microbes hampered diversification within the microbial community.

"Our results demonstrate that environmental complexity alone is not sufficient for maintaining community diversity, and provide practical guidance for designing and controlling microbial ecosystems," the authors write.

So, what are the mechanisms that control a microbiome's diversity? "It's going to take some time to figure out the cause of all these interactions," Segrè says.

Although increasing the variety of food sources didn't increase the variety of microbial species within their experiments, more food did fuel more microbial growth. "We found yield depends on the total number of carbon sources, but not on the variety of those sources," Segrè says. "It's like people at a picnic--if enough people come to a picnic, no matter what the spread of different foods, eventually everything will be eaten up. In many of our experiments, the microbial communities used up every last bit of carbon source to the fullest extent."

Pacheco adds that if somebody can consume something, somebody else can outcompete them for it. "Our experiments showed that the crucial modulator in microbial diversity is how much these different organisms compete with one another for resources," he says. "The more organisms compete, the less diverse that community is going to be."

The team plans to do more research into additional environmental factors, investigating how nutrient access and variety changes microbial communities over time, and how the medium that the microbial community lives in affects their consumption and secretion of molecules. They are also exploring how metabolic processes amongst different microbial species could interact and interplay with each other, and how the ability of some organisms to sequentially or simultaneously consume multiple resources affects the microbiome overall.

Further unlocking and eventually harnessing all these environmental "dials and knobs" could open doors to using microbiomes to influence human metabolisms and health or disease states in people and in natural ecosystems.

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Funders: Howard Hughes Medical Institute, National Academies of Sciences, Engineering, and Medicine, Ford Foundation, US Department of Energy, National Institutes of Health, National Science Foundation, Human Frontiers Science Program, Boston University Interdisciplinary Biomedical Research Office

Genomics-informed decisions can help save species from extinction

LUND UNIVERSITY

Research News

"Many species are threatened by extinction, both locally and globally. For example, we have lost about ten vertebrate species in Sweden in the last century. However, all these species occur elsewhere in Europe, which means that they could be reintroduced into Sweden. Our computer simulations show how we could theoretically maximize the success of such reestablishments", says Bengt Hansson, biologist at Lund University.

In a new study published in Science, the researchers investigated which individuals might be most suited for translocation to new populations. To date, conservation geneticists have opted to select the most genetically variable individuals. However, the authors argue that is important to consider what type of genetic variation is being move around. Using computer simulations, they showed that harmful mutations present in the genome of translocated individuals can cause problems in future generations. This so called "mutation load" could jeopardize the viability of the new population in the long run and eventually led to extinction.

According to Hansson and van Oosterhout, geneticist at University of East Anglia, Norwich, who led the study, the best choice is to exclude individuals with many harmful mutations, whilst at the same time, selecting individuals from multiple different source populations.

"Active translocation of animals between localities is sometimes the last option available to conservation biologists. By carefully selecting individuals based on their low mutation load, we can minimize the loss of fitness that is normally associated with inbreeding in small populations", says Bengt Hansson.

Huge advances have been made in DNA sequencing technologies, and the whole genomes of individuals can now be sequenced for relatively little costs. This opens up new possibilities to improve the conservation management of threatened species.

"For many species of mammals and birds, we now know which mutations are harmful. Similar mutations are also found in humans, so we understand what they do, and hence, we know what to look out for when analyzing the sequence data of those species. The advantage of using DNA sequencing is that we can see these mutations in the genome, even if an individual carries just a single copy of the mutant gene. This means we can select against those bad mutations even before they cause a problem. Our computer model shows that at least theoretically, this ensures the best probability for population survival. This could help conservation managers in picking the optimal individuals of a threatened species for translocation into a new habitat", says van Oosterhout.

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A shark mystery millions of years in the making

YALE UNIVERSITY

Research News

The biggest shark attack in history did not involve humans.

A new study by Earth scientists from Yale and the College of the Atlantic has turned up a massive die-off of sharks roughly 19 million years ago. It came at a period in history when there were more than 10 times more sharks patrolling the world's oceans than there are today.

For now, researchers don't know the cause of the shark die-off.

"We happened upon this extinction almost by accident," said Elizabeth Sibert, a Hutchinson postdoctoral associate in Yale's Department of Earth and Planetary Sciences and the Yale Institute for Biospheric Studies. She is lead author of the new study, which appears in the journal Science.

"I study microfossil fish teeth and shark scales in deep-sea sediments, and we decided to generate an 85-million-year-long record of fish and shark abundance, just to get a sense of what the normal variability of that population looked like in the long term," Sibert said. "What we found, though, was this sudden drop-off in shark abundance around 19 million years ago, and we knew we had to investigate further."

How big was the drop-off? Sibert said more than 70% of the world's sharks died off -- with an even higher death toll for sharks in the open ocean, rather than coastal waters. It was twice the level of extinction that sharks experienced during the Cretaceous-Paleogene mass extinction event 66 million years ago that wiped out three-quarters of the plant and animal species on Earth.

Adding to the mystery is the fact that there is no known climate calamity or ecosystem disruption that occurred at the time of the steep drop in shark populations. "This interval isn't known for any major changes in Earth's history," said Sibert, "yet it completely transformed the nature of what it means to be a predator living in the open ocean."

Co-author Leah Rubin, an incoming doctoral student at the State University of New York College of Environmental Science and Forestry, was a student at the College of the Atlantic at the time of the research.

"The current state of declining shark populations is certainly cause for concern and this paper helps put these declines in the context of shark populations through the last 40 million years," Rubin said. "This context is a vital first step in understanding what repercussions may follow dramatic declines in these top marine predators in modern times."

The researchers noted that past discoveries of extinction events have led to waves of new research to learn the origins of the die-off and whether it signaled a larger, previously unknown, perturbance in global ecosystems.

For example, further research might confirm whether the shark-off caused remaining shark populations to change their habitat preferences to avoid the open ocean, Sibert and Rubin said. Additional research might also help to explain why shark populations did not rebound after the die-off 19 million years ago.

"This work could tip-off a race to understand this time period and its implications for not only the rise of modern ecosystems, but the causes of major collapses in shark diversity," said Pincelli Hull, an assistant professor of Earth and planetary science at Yale, who was not part of the study. "It represents a major change in ocean ecosystems at a time that was previously thought to be unremarkable."

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Stone Age raves to the beat of elk tooth rattles?

UNIVERSITY OF HELSINKI

VIDEO: HYPOTHETICAL RECONSTRUCTION OF TOOTH ORNAMENTS FOUND IN THE LATE MESOLITHIC GRAVES OF YUZHNIY OLENIY OSTROV: 94 EURASIAN ELK TEETH SEWN ON AN APRON HIT AND BOUNCE OFF THE SUBSTRATUM AND... view more

CREDIT: JULIA SHPINITSKAYA

"Ornaments composed of elk teeth suspended from or sown on to clothing emit a loud rattling noise when moving," says auditory archaeologist and Academy of Finland Research Fellow Riitta Rainio from the University of Helsinki. "Wearing such rattlers while dancing makes it easier to immerse yourself in the soundscape, eventually letting the sound and rhythm take control of your movements. It is as if the dancer is led in the dance by someone."

Rainio is well versed in the topic, as she danced, for research purposes, for six consecutive hours, wearing elk tooth ornaments produced according to the Stone Age model. Rainio and artist Juha Valkeapää held a performance to find out what kind of wear marks are formed in the teeth when they bang against each other and move in all directions. The sound of a tooth rattler can be clear and bright or loud and pounding, depending on the number and quality of the teeth, as well as the intensity of movement.

Microanalysis demonstrates that tooth wear marks are the result of dancing

The teeth worn out by dancing were analysed for any microscopic marks before and after the dancing. These marks were then compared to the findings made in the Yuzhniy Oleniy Ostrov graves by Evgeny Girya, an archaeologist specialised in micro-marks at the Russian Academy of Sciences. Girya documented and analysed the wear marks in the elk teeth found in four graves chosen for the experiment. Comparing the chips, hollows, cuts and smoothened surfaces of the teeth, he observed a clear resemblance between teeth worn out by dancing and the Stone Age teeth. However, the marks in the Stone Age teeth were deeper and more extensive. According to Girya, the results show that the marks are the result of similar activity.

"As the Stone Age teeth were worn for years or even decades, it's no surprise that their marks are so distinctive," Girya says.

Associate Professor of Archaeology Kristiina Mannermaa from the University of Helsinki is excited by the research findings.

"Elk tooth rattlers are fascinating, since they transport modern people to a soundscape that is thousands of years old and to its emotional rhythms that guide the body. You can close your eyes, listen to the sound of the rattlers and drift on the soundwaves to a lakeside campfire in the world of Stone Age hunter-gatherers."

A total of 177 graves of women, men and children have been found in the Yuzhniy Oleniy Ostrov burial site, of which more than half contain several elk tooth ornaments, some of them composed of as many as over 300 individual teeth.

CAPTION

Adult male from grave 76a in Yuzhniy Oleniy Ostrov drawn as if he were alive during a dance session: 140 elk teeth on the chest, waist, pelvis, and thighs rattle rhythmically and loudly.

CREDIT

Artist Tom Bjorklund

Five million years of climate change preserved in one place

An 80-meter-thick sedimentary succession at Charyn Canyon, Kazakhstan, recorded interactions between land, atmosphere and ocean

MAX PLANCK INSTITUTE FOR CHEMISTRY

Research News

IMAGE: CHARLOTTE PRUD'HOMME IS ABSEILING TO COLLECT SOIL SAMPLES. THE 80-METER-THICK SEDIMENTARY SEQUENCE IN CHARYN CANYON, KAZAKHSTAN, DOCUMENTS CLIMATE CHANGE OVER THE PAST 5 MILLION YEARS. view more
CREDIT: CHARLOTTE PRUD'HOMME, MPI FOR CHEMISTRY

Paleo researcher Charlotte Prud'homme, who until recently worked at the Max Planck Institute for Chemistry and is now a researcher at the Université Lausanne, explains: "The 80-meter-thick sedimentary sequence we found at Charyn Canyon in southeast Kazakhstan provides us with a virtually continuous record of five million years of climate change. This is a very rare occurrence on land!" The alternating dust and soil layers provide the first reliable evidence, in one place, of long-term interactions between major climate systems on the Eurasian continent. "Over the past five million years, the land surfaces of Eurasia appear to have more actively contributed to the land-atmosphere-ocean water-cycle than previously acknowledged. The sediments preserved at Charyn Canyon acted as a litmus test for the influx of freshwater into the Arctic Ocean, stimulating the transport of moist air masses from the North Atlantic back onto land via westerly air flows," corresponding author Prud'homme says. The results of the research have now been published in the scientific journal Communications Earth and Environment.

The researchers focused their investigation on the Pliocene and Pleistocene periods. The Pliocene, five to 2.6 million years ago, represents the best analogue for the climatic conditions of the Anthropocene: this geologic time period was the last time concentration of carbon dioxide in the atmosphere was comparable to today, around 400 parts per million (ppm). "That's why our insights from the Charyn Canyon sediments are so essential for understanding future climate," Prud'homme says.

Until now, little has been known about the role Central Asia plays in global climate evolution past and present. Earth's climate evolution over the past five million years has been understood mainly from the perspective of marine mechanisms. In contrast, the significance of climate feedbacks that originated on land - rather than in the oceans, lakes or ice cores - has remained largely unexplored. The international research team has filled this gap with their field research in Charyn Canyon.

Interactions between mid- and high-latitude climatic systems

The geographical location of the study site in the middle of Central Asia was of key importance to the team: "We needed to find a place that was inland and as far away from the ocean as possible," Kathryn Fitzsimmons, Group Leader of the Terrestrial Paleoclimate Reconstruction Research Group at the Max Planck Institute for Chemistry, explains. "We could hardly find a more continental situation than at Charyn Canyon in southeastern Kazakhstan." The semi-arid climate of the canyon, and its landscape, was shaped by the interaction between the mid-latitude westerlies and the high-latitude polar fronts, and by sediment transported from the nearby Tien Shan mountains. Charyn Canyon is ideal, according to Kathryn Fitzsimmons, for studying long-term land-climate feedback mechanisms.

The researchers examined the 80-meter-thick sedimentary succession and sampled by abseil to ensure continuous coverage of the record. By measuring the relative concentrations of isotopes within soil carbonates, they reconstructed the changing availability of moisture in the soil through time. A combination of paleomagnetic analyses and absolute uranium-lead dating of soil carbonates established the age and accumulation rates of the sediment record. The soil samples revealed a region characterized by ever-increasing aridity over the last five million years. In the early Pliocene, the soil was significantly wetter than in subsequent epochs or than today's climate. This process of aridification was not linear, however; it was interrupted by short-term climate fluctuations which provide insights into the interaction between the mid-latitude westerly winds and the Siberian high-pressure system.

Interaction between the Siberian high and rain-bringing westerlies

The research at Charyn Canyon enabled the scientists to investigate the long-term interaction of the Siberian high with the rain-bringing westerlies. Kathryn Fitzsimmons says: "We're confident that the changes in soil moisture we found at our site can also be used as a proxy for Siberian river activity further north." The hydroclimate at Charyn Canyon reflects that of the steppe to the north, from where a number of large Siberian rivers, such as the Irtysh and Ob, flow, she says. These are similarly influenced by the dynamics of the Siberian high and westerly air masses. One particular phase where this link is important stands out: a sustained period of wet conditions at Charyn Canyon just prior to the first major global glaciation around 3.3 million years ago. It is likely that these wet conditions extended to the Siberian rivers to the north, whose outflow of fresh water to the Arctic ocean may have breached a tipping point for widespread increased sea ice formation.

The information from this most complete terrestrial climate archive for the past five million years provides a very valuable basis for future climate models. Charlotte Prud'homme literally says, "We have opened a door."

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Information for editors:

Researchers from the following institutions were involved in the field research at Charyn Canyon:

Max Planck Institute for Chemistry, Mainz
Instituto de Geociências e Ciências Exatas, Universidade Estadual Paulista, Rio Claro, Brazil.
Université de Paris, Institut de Physique du Globe de Paris, Paris, France.
Université Aix-Marseille, CNRS, IRD, INRAE, Coll France, CEREGE, Aix-en-Provence, France.
Institute of Geological Sciences K. Satpaeva, Almaty, Kazakhstan
Institute of Geosciences, Goethe University, Frankfurt, Germany
Frankfurt Element and Isotope Research Center (FIERCE), Goethe University, Frankfurt, Germany

Plant competition during climate change

UNIVERSITY OF FREIBURG

Research News

How plants cope with stress factors has already been broadly researched. Yet what happens when a plant is confronted with two stressors simultaneously? A research team working with Simon Haberstroh and Prof. Dr. Christiane Werner of the Chair of Ecosystem Physiology at the Institute of Forest Sciences and Natural Resources (UNR) of the University of Freiburg is investigating this. Together with colleagues from the Forest Research Center of the School of Agriculture of the University of Lisbon in Portugal and the Institute of Meteorology and Climate Research at the Karlsruhe Institute of Technology - KIT, they have published their findings in the specialist journal "New Phytologist."

The researchers set up a field study in the Park Tapada Real in the small Portuguese town of Vila Viçosa. The focus was on how cork oak (Quercus suber) handles two stressors: the first being extreme drought; and the other, the invasive plant species gum rockrose (Cistus ladanifer). The study has great relevance because both stress factors are currently clearly on the increase. At the same time, there was a gap in research on the issue. Researchers have up to now rarely looked at how different, interacting stress factors influence ecosystems.

The researchers were in part surprised by their findings. "The factors interacted more dynamically than we expected," says Haberstroh, who did the investigative work for his doctoral thesis. During wet years, the interacting stressors didn't cause any significant changes in the cork oak, while in dry conditions, the factors either amplified or buffered each other. One surprising result was also that cork oak, despite the double burden, was able to recover better than had been expected after extreme drought. The researchers observed that happens above all when the invasive gum rockrose shrubs were seriously compromised by the drought as well. The team will continue its work in Portugal to gather more data and look at long-term trends.

"These new research findings contribute to better understanding and more expedient care of ecosystems," Haberstroh explains. "Using them we can, for example, develop rules for particularly dry years, which is a central issue in times of climate change," he says.

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Original publication

Haberstroh, S., Caldeira, M. C., Lobo-do-Vale, R., Martins, Joana I., Moemken, J., Pinto, J. G., Werner, C. (2021): Non-linear plant-plant interactions modulate impact of extreme drought and recovery on a Mediterranean ecosystem. In: New Phytologist. DOI: 10.1111/nph.17522

Ten-fold increase in carbon offset cost predicted

UNIVERSITY COLLEGE LONDON

Research News

IMAGE: NOTE: "NATIONALLY DETERMINED CONTRIBUTION (NDC) ADJUSTMENT " REFERS TO THE SCENARIO WHERE GOVERNMENTS TAKE RESPONSIBILITY FOR REDUCING EMISSIONS IN THEIR PARIS COMMITMENTS, SO ONLY HIGHER COST ABATEMENT OPTIONS ARE AVAILABLE TO... view more
CREDIT: TROVE RESEARCH

The cost of offsetting corporate carbon emissions needs to increase ten-fold to drive meaningful climate action, says a landmark report by Trove Research and UCL.

Current prices of carbon offsets are unsustainably low and need to increase significantly to encourage greater investment in new projects that remove carbon from the atmosphere.

If prices stay low companies could be accused of greenwashing their emissions, as real emissions reduction and carbon removals are more costly than today's prices.

Prices of carbon credits used by companies to offset their emissions are currently low, due to an excess of supply built up over several years, together with issues over whether payments for credits really result in additional reductions in carbon emissions.

According to the research, titles Future Demand, Supply and Prices for Voluntary Carbon Credits - Keeping the Balance, without this surplus, prices would be around $15/tCO2e higher, compared to $3-5t/CO2e today.

The research shows, however, that the surplus will not last forever, with demand for carbon credits expected to increase five to ten-fold over the next decade as more companies adopt Net Zero climate commitments.

This growth in demand should see carbon credit prices rise to $20-50/tCO2e by 2030, as more investment is required in projects that take carbon out of the atmosphere in the long-term. These prices are needed, for example, to incentivise landowners to forgo income from agriculture and instead preserve forests and plant trees.

With a further increase in demand expected by 2040 and 2050, carbon credit prices would rise in excess of $50/tCO2e.

If governments successfully reduce emissions through domestic policies, fewer carbon credits will be available to businesses through the voluntary market. This would increase carbon credit prices further, potentially reaching $100/tCO2e.

If carbon credit prices remain significantly below these forecast levels, companies could be open to criticisms of greenwashing, claiming credit for emission reductions that would have been undertaken anyway.

The analysis also shows that the contribution of the voluntary market to reducing world emissions needs to be seen in perspective. Even at prices of $100/tCO2e the technologies assessed in this study (reducing deforestation, forest restoration, CCS, BECCs and renewables in least developed countries) could deliver around 2bn tCO2e per year of emission reductions on average between now and 2050.

This is about 4% of world greenhouse gas emissions, and 10% of the gap between global "business as usual" emissions in 2030 and pledges in the Paris Agreement by 2030, showing that the market for offsets will be modest compared to economy-wide emissions reductions needed to reach the Paris targets and net zero by 2050.

However, over the next decade the voluntary market will provide a valuable financing mechanism to support the protection of existing forests and restoring degraded habitats, providing immediate climate and biodiversity benefits while other technologies that can remove carbon from the atmosphere are scaled up.

Guy Turner, CEO of Trove Research and lead author of the study said "It is encouraging to see so many companies setting Net Zero and Carbon Neutral climate targets. What this new analysis shows is that these companies need to plan for substantially higher carbon credit prices and make informed trade-offs between reducing emissions internally and buying credits from outside the company's value chain."

Co-author of the study Professor Mark Maslin (UCL Geography) said: "Customers, clients, investors and employees all want companies to become more sustainable and achieve net zero carbon as soon as possible. Even with ambitious carbon reduction plans there are some company emissions that are currently unavoidable and this is where carbon offsetting is essential. But everyone wants a carbon credit system that is reliable and really does remove carbon from the atmosphere - what this groundbreaking report shows is that this will cost significantly more than companies are paying now."

Co-author of the study Professor Simon Lewis (UCL Geography) said: "The current market in carbon credits is the wild-west, where too often anything goes. A clean-up and independent regulation is required, which will increase the price of carbon credits. This is because in reality it is costly to remove carbon dioxide from the atmosphere. Overall it will be cheaper in the long-run to invest in moving to zero emissions rather than relying on offsets. But for those emissions that remain, the true price of removing carbon from the atmosphere must be paid, as the alternative is greenwash."

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Future Demand, Supply and Prices for Voluntary Carbon Credits - Keeping the Balance will be published and available to download on the Trove Research website.

Notes to Editors

For more information or to speak to the researchers involved, please contact:

Jane Bolger, UCL Media Relations: T: +44 (0) 7990 675 947, E: j.bolger@ucl.ac.uk

Guy Turner, CEO Trove Research T: +44 7801 140696 E: guy.turner@trove-research.com

Copies of Future Demand, Supply and Prices for Voluntary Carbon Credits - Keeping the Balance are available to download here: https://wetransfer.com/downloads/adb46524d19d29c4ca3b69e8534f029020210603121350/d05a959b1f2ef7aec0ae8c491415a3c820210603121416/6d5324

About Trove Research

Trove Research is an independent research and data company focused on solving the climate change challenge through objective and rigorous analysis. We work across the range of climate policy areas, including carbon markets and the broader energy transition. We develop analytical tools and insights for use by companies, governments, NGOs and other research organisations to gain deeper understanding of complex sustainability decisions.

For more information see: http://www.trove-research.com; http://www.trove-intelligence.com

About UCL - London's Global University

UCL is a diverse community with the freedom to challenge and think differently.

Our community of more than 41,500 students from 150 countries and over 12,500 staff pursues academic excellence, breaks boundaries and makes a positive impact on real world problems.

We are consistently ranked among the top 10 universities in the world and are one of only a handful of institutions rated as having the strongest academic reputation and the broadest research impact.

We have a progressive and integrated approach to our teaching and research - championing innovation, creativity and cross-disciplinary working. We teach our students how to think, not what to think, and see them as partners, collaborators and contributors.

For almost 200 years, we are proud to have opened higher education to students from a wide range of backgrounds and to change the way we create and share knowledge.

We were the first in England to welcome women to university education and that courageous attitude and disruptive spirit is still alive today. We are UCL.

Find out how UCL is helping lead the global fight against COVID-19 http://www.ucl.ac.uk/covid-19-research

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