Kangaroo fecal microbes could reduce methane from cows

Peer-Reviewed Publication

WASHINGTON STATE UNIVERSITY

RICHLAND, Wash. – Baby kangaroo feces might help provide an unlikely solution to the environmental problem of cow-produced methane. A microbial culture developed from the kangaroo feces inhibited methane production in a cow stomach simulator in a Washington State University study.

After researchers added the baby kangaroo culture and a known methane inhibitor to the simulated stomach, it produced acetic acid instead of methane. Unlike methane, which cattle discard as flatulence, acetic acid has benefits for cows as it aids muscle growth. The researchers published their work in the journal Biocatalysis and Agricultural Biotechnology.

“Methane emissions from cows are a major contributor to greenhouse gases, and at the same time, people like to eat red meat,” said Birgitte Ahring, corresponding author on the paper and a professor in with the Bioproducts, Sciences and Engineering Laboratory at the WSU Tri-Cities campus. “We have to find a way to mitigate this problem.”

Reducing the burps and farts of methane emissions from cattle is no laughing matter. Methane is the second largest greenhouse gas contributor and is about 30 times more potent at heating up the atmosphere than carbon dioxide. More than half of the methane released to the atmosphere is thought to come from the agricultural sector, and ruminant animals, such as cattle and goats, are the most significant contributors. Furthermore, the process of producing methane requires as much as 10% of the animal’s energy.

Researchers have tried changing cows’ diets as well as giving them chemical inhibitors to stop methane production, but the methane-producing bacteria soon become resistant to the chemicals. They also have tried to develop vaccines, but a cow’s microbiome depends on where it’s eating, and there are far too many varieties of the methane-producing bacteria worldwide. The interventions can also negatively affect the animals’ biological processes.

The WSU researchers study fermentation and anaerobic processes and had previously designed an artificial rumen, the largest stomach compartment found in ruminant animals, to simulate cow digestion. With many enzymes that are able to break down natural materials, rumens have “amazing abilities,” said Ahring, who is also a professor in the Gene and Linda Voiland School of Chemical Engineering and Bioengineering and in Biological System Engineering.  

Looking to investigate how to outcompete the methane-producing bacteria in their reactor, Ahring learned that kangaroos have acetic acid-producing, instead of methane-producing, bacteria in their foregut. Her students tracked down some kangaroos, took samples and learned that the specialized acetic acid-producing process only occurred in baby kangaroos – not in adults. Unable to separate out specific bacteria that might be producing the acetic acid, the researchers used a stable mixed culture developed from the feces of the baby kangaroo.

After initially reducing the methane-producing bacteria in their reactor with a specialized chemical, the acetic acid bacteria were able to replace the methane-producing microbes for several months with a similar growth rate as the methane-producing microbes.

While the researchers have tested their system in the simulated rumen, they hope to try it on real cows sometime in the future.

“It is a very good culture. I have no doubt it is promising,” Ahring said. “It could be really interesting to see if that culture could run for an extended period of time, so we would only have to inhibit the methane production from time to time. Then, it could actually be a practice.”

The work was supported by WSU’s College of Agricultural, Human, and Natural Resource Sciences’ Appendix A program.

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JOURNAL

Biocatalysis and Agricultural Biotechnology

DOI

10.1016/j.bcab.2022.102526 

ARTICLE TITLE

Reducing methane production from rumen cultures by bioaugmentation with homoacetogenic bacteria

Let’s talk to a moth about sex: Polish chemists have 'made a deal' with a butterfly threatening pine forests

Peer-Reviewed Publication

INSTITUTE OF PHYSICAL CHEMISTRY OF THE POLISH ACADEMY OF SCIENCES

 

IMAGE: A DENDROLIMUS PINI, L. IS A HUNGRY BEAST HIDING IN FORESTS. THE ENLIGHTENED PROF. RAFAŁ SZMIGIELSKI FOUND A WAY TO FACE IT. THE PHOTO WAS TAKEN IN THE BOOKSTORE WRZENIE ŚWIATA. PHOTO: GRZEGORZ KRZYZEWSKI view more 

CREDIT: SOURCE IPC PAS, GRZEGORZ KRZYZEWSKI

Beyond the seven mountains and forests, a hungry beast was stealing away. Does this sound like a fairy tale? In reality, such a beast does exist. It is the caterpillar of the nocturnal pine-tree lappet moth (Dendrolimus pini, L.), which feeds on pine needles and wreaks havoc in the forests on a massive scale. However, words of love between these night butterflies may be the key to preventing outbreaks of their terrifying hunger. Monitoring the population of D. pini and its control has been possible thanks to the recent discovery of a team of scientists from the Institute of Physical Chemistry of the Polish Academy of Sciences (IPC PAS) led by Prof. Rafał Szmigielski. They have deciphered the chemical hieroglyphs of the moth's language by which females attract males, finding a way to deal with the voracious beast and save the pine forests. Let's take a closer look at their discovery.

 

The voracious caterpillars of the pine-tree lappet Dendrolimus pini can destroy tens of thousands of hectares of coniferous forests. Despite the lack of ecological solutions to effectively combat this insect, we will not be saying goodbye to our pine trees. Scientists from the Institute of Physical Chemistry of the Polish Academy of Sciences (IPC PAS) have found a way towards effective protection against the lappet moth. They have deciphered the chemical 'love words' by which female Dendrolimus pini moths attract their males. A new pheromone blend based, among others, on newly discovered biocomponents of the sex pheromone of the voracious insect developed by scientists from the IPC PAS may serve as an effective tool for monitoring and, in the long term, also for controlling the abundance of pine-tree lappet moth in our forests.

 

The pine-tree lappet moth Dendrolimus pini, a moth with a stocky body and grey-brown coloration, is one of Poland's most giant nocturnal butterflies. After overwintering in the mulch, the caterpillars of this butterfly climb into the crowns of pine trees, where they busily devour the needles. As up to several hundred perpetually hungry caterpillars can feed on a single tree, a rapid increase in the Dendrolimus pini population can lead to the extermination of large forest areas. Without ecological and efficient tools for controlling the moth’s population, the data on their population growth is crucial. However, synthetic pheromone traps used by foresters to attract Dendrolimus pini males were found to be insufficient. In the project carried out by scientists from the IPC PAS in collaboration with the Institute of Forestry Research (IBL), a novel and far more effective sex pheromone lure for the pine-tree moth has been developed.

 

The research into the pine-tree lappet moth's chemical love language proved more difficult than scientists had anticipated for entirely surprising reasons. The study began by the identifying the pheromones' components secreted by young Dendrolimus pini females. To develop a preparation to attract the voracious males, all the chemical compounds that are components of the sexual pheromone were put under the microscope. Interestingly, in addition to the previously known chemical compounds, the secreted 'pheromone perfume' was found to contain other components, including - compounds derived from Scot’s pine needles and other organic compounds hitherto undiscovered, either significantly influencing the behavior of the caterpillars. The captured substances were chromatographically separated into single components and subjected to a detailed chemical analysis using tandem mass spectrometry. The comparison of the molecular structures of the identified Dendrolimus pini sex pheromone components with the composition of a commercially available product strengthened the researchers' conviction that one of the most important reasons for the pine-tree lappet moths' poor response to the synthetic pheromone was its oversimplified chemical composition and the lack of key bioactive components.

 

"We aimed to identify all the substances in the pheromones secreted by the Dendrolimus pini moth and to create a unique formulation to divert the lappet moth's attention from the conifers, including the Scot’s pine trees. And all this to save the forests from Dendrolimus pini hunger," says Prof. Rafał Szmigielski.

 

Based on the results of detailed analyses, chemists from the IPC PAS designed new formulations of the pheromone mixtures, which were subjected to numerous tests in a laboratory framework using modern bioanalytical techniques, such as wind tunnel, olfactometry, and electroanthenography, and then in the field measurements. Dendrolimus pini moths were placed in wind tunnels exposed to specific chemicals and self-built terraria to test behavior in the natural environment. Hundreds of experiments were carried out with female and male butterflies in this way, exposing them to various compounds. The scientists looked at (Z5)-dodecanal, abbreviated as (Z5)-12:Ald, which occurs naturally in pine needles and attracts caterpillars, and (Z5)-decen-1-yl acetate, known as (Z5)-10:OAc, which in turn discourages them. Studies have shown the critical role of these two compounds on barnacle behaviour.

 

"The mixture of chemical compounds we have identified and patented can - naturally with appropriate conventionality - be treated as certain words of non-trivial structure, spoken in the chemical language of the moth. The main accent here is on two 'sounds,' one of which people pronounce differently from the other. For this chemical ''I love you'' to sound convincing, additional words are needed to increase the carrying capacity of the main message, such as plant-derived compounds,” – explains Prof. Rafał Szmigielski.

 

Previous attempts attracted a maximum of a few dozen pine barnacle males per trap over several weeks to pheromone traps. Meanwhile, chemical calling using a mixture of substances developed by a group from the IPC PAS increased this number to as high as 160 males per trap in just 3-4 days. Foresters unanimously considered such an increase in insect interest to be a huge success, bringing us closer to saving the pine forests from the appetite of these voracious insects.

 

Identifying new components of the sex pheromone emitted by the female moth Dendrolimus pini and their correlation with the specific behavior of this tiny insect is a step forward toward the effective protection of pine forests. The scientists' research into creating the synthetic pheromone lures is also more than just monitoring the moth's behavior. It is, first and foremost, the interdisciplinary work, a love of nature, and the fascinating the micro-world.

 

This work received financing from the National Centre for Research and Development (contract PBS2/A9/25/2013).

SCIENTIFIC PAPERS:

Rudziński KJ, Staszek D, Asztemborska M, Sukovata L, Raczko J, Cieślak M, Kolk A, Szmigielski R.

Newly Discovered Components of Dendrolimus pini Sex Pheromone.

Insects. 2022; 13(11):1063

https://doi.org/10.3390/insects13111063

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JOURNAL

Insects

DOI

10.3390/insects13111063 

Rats trade initial rewards for long-term learning opportunities

When deciding on responses to a new stimulus, slower initial response times can maximize long-term reward through learning

Peer-Reviewed Publication

ELIFE

Scientists have provided evidence for the cognitive control of learning in rats, showing they can estimate the long-term value of learning and adapt their decision-making strategy to take advantage of learning opportunities.

The findings suggest that, by taking longer over a decision, rats may sacrifice immediate rewards to increase their learning outcomes and achieve greater rewards over the entire course of a task. The results are published today in eLife.

An established principle of behavioural neuroscience is the speed-accuracy trade-off, which is seen across many species, from rodents to primates. The principle describes the relationship between an individual’s willingness to respond slowly and make fewer errors compared to their willingness to respond quickly and risk making more errors. 

“Many studies in this area have focused on the speed-accuracy trade-off, without taking learning outcomes into account,” says lead author Javier Masís, who at the time was a PhD student at the Department of Molecular and Cellular Biology, and the Center for Brain Science, Harvard University, US, and is now a Presidential Postdoctoral Research Fellow at the Princeton Neuroscience Institute at Princeton University, US. “We aimed to investigate the difficult intertemporal choice problem that exists when you have the possibility to improve your behaviour through learning.”

For their study, Masís and colleagues sought to first establish whether rats were able to solve the speed-accuracy trade-off. The team set up an experiment where rats, upon seeing one of two visual objects that could vary in their size and rotation, decided whether the visual object was the one that corresponded to a left response, or a right response, and licked the corresponding touch-sensitive port once they had decided.   If the rats licked the correct port, they were rewarded with water, and if they licked the wrong port, they were given a timeout. 

The team investigated the relationship between error rate (ER) and reaction time (RT) during these trials, using the Drift-Diffusion Model (DDM) – a standard decision-making model in psychology and neuroscience in which the decision maker accumulates evidence through time until the level of evidence for one alternative reaches a threshold. The subject’s threshold level controls the speed-accuracy trade-off. Using a low-threshold yields fast, but error-prone responses, whereas a high-threshold yields slow, but accurate responses. For every difficulty level, however, there is a best threshold to set that optimally balances speed and accuracy, allowing the decision maker to maximise their instantaneous reward rate (iRR). Across difficulties, this behaviour can be summarised through a relationship between ER and RT called the optimal performance curve (OPC). After learning the task fully, over half of the trained rats reached the OPC, demonstrating that well-trained rats solve the speed-accuracy trade-off.

At the start of training, though, all rats gave up over 20% of their iRR, whereas towards the end, most rats near optimally maximised iRR. This prompted the question: if rats maximise instantaneous rewards by the end of learning, what governs their strategy at the beginning of learning?

To answer this, the team adapted the DDM as a recurrent neural network (RNN) that could learn over time and developed the Learning Drift-Diffusion Model (LDDM), enabling them to investigate how long-term perceptual learning across many trials is influenced by the choice of decision time in individual trials. The model was designed with simplicity in mind, to highlight key qualitative trade-offs between learning speed and decision strategy. The analyses from this model suggested that rats adopt a ‘non-greedy’ strategy that trades initial rewards to prioritise learning and therefore maximise total reward over the course of the task. They also demonstrated that longer initial reaction times lead to faster learning and higher reward, both in an experimental and simulated environment.

The authors call for further studies to consolidate these findings. The current study is limited by the use of the DDM to estimate improved learning. The DDM, and therefore LDDM, is a simple model that is a powerful theoretical tool for understanding specific types of simple choice behaviour that can be studied in the lab, but it is not capable of quantitatively describing more naturalistic decision-making behaviour. Furthermore, the study focuses on one visual perceptual task; the authors therefore encourage further work with other learnable  tasks across difficulties, sensory modalities and organisms.

“Our results provide a new view of the speed-accuracy trade-off by showing that perceptual decision-making behaviour is strongly shaped by the stringent requirement to learn quickly,” claims senior author Andrew Saxe, previously a postdoctoral research associate at the Department of Experimental Psychology, University of Oxford, UK, and now Sir Henry Dale Fellow and Associate Professor at the Gatsby Computational Unit and Sainsbury Wellcome Center, University College London, UK. 

“A key principle that our study propounds”, explains Javier Masís, “is that natural agents take into account the fact that they can improve through learning, and that they can and do shape the rate of that improvement through their choices. Not only is the world we live in non-stationary; we are also non-stationary, and we take that into account as we move around the world making choices.”  “You don’t learn the piano by futzing around the keys occasionally,” adds Saxe. “You decide to practise, and you practise at the expense of other more immediately rewarding activities because you know you’ll improve and it’ll probably be worth it in the end.”

##

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About eLife

eLife transforms research communication to create a future where a diverse, global community of scientists and researchers produces open and trusted results for the benefit of all. Independent, not-for-profit and supported by funders, we improve the way science is practised and shared. From the research we publish, to the tools we build, to the people we work with, we’ve earned a reputation for quality, integrity and the flexibility to bring about real change. eLife receives financial support and strategic guidance from the Howard Hughes Medical Institute, Knut and Alice Wallenberg Foundation, the Max Planck Society and Wellcome. Learn more at https://elifesciences.org/about.

To read the latest Neuroscience research published in eLife, visit https://elifesciences.org/subjects/neuroscience.

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JOURNAL

eLife

DOI

10.7554/eLife.64978 

ARTICLE TITLE

Strategically managing learning during perceptual decision making

ARTICLE PUBLICATION DATE

14-Feb-2023

Upsurge in rocket launches could impact the ozone layer

University of Canterbury (UC) researchers have summarised the threats that future rocket launches would pose to Earth’s protective ozone layer, in a new review article published in the Journal of the Royal Society of New Zealand.

Peer-Reviewed Publication

TAYLOR & FRANCIS GROUP

University of Canterbury (UC) researchers have summarised the threats that future rocket launches would pose to Earth’s protective ozone layer, in a new review article published in the Journal of the Royal Society of New Zealand.

The ozone layer, which protects life on Earth from harmful ultraviolet (UV) rays from the sun, was severely damaged in the 1980s and 1990s due to chlorofluorocarbons (CFCs) — chemicals used in aerosols and refrigeration. Thanks to coordinated global action and legislation, the ozone layer is now on track to heal this century.

Rocket launches emit both gases and particulates that damage the ozone layer. Reactive chlorine, black carbon, and nitrogen oxides (among other species) are all emitted by contemporary rockets. New fuels like methane are yet to be measured.

“The current impact of rocket launches on the ozone layer is estimated to be small but has the potential to grow as companies and nations scale up their space programmes,” Associate Professor in Environmental Physics Dr Laura Revell says.

“Ozone recovery has been a global success story. We want to ensure that future rocket launches continue that sustainable recovery.”

Global annual launches grew from 90 to 190 in the past 5 years, largely in the Northern Hemisphere. The space industry is projected to grow more rapidly: financial estimates indicate the global space industry could grow to US$3.7 trillion by 2040.

“Rockets are a perfect example of a ‘charismatic technology’ – where the promise of what the technology can enable drives deep emotional investment – extending far beyond what the technology also affects,” Rutherford Discovery Fellow and planetary scientist UC senior lecturer Dr Michele Bannister says.

Rocket fuel emissions are currently unregulated, both in Aotearoa New Zealand and internationally.

UC Master’s student Tyler Brown, who was involved in the research, says Aotearoa New Zealand is uniquely positioned to both lead and participate in this field. “New Zealand’s role as a major player in the global launch industry means we can help steer the conversation. We stand to benefit enormously from additional growth in our domestic space industry, and with that comes the opportunity to ensure that global activities are sustainable for the planet as a whole.”

The review lays out detailed plans of action for companies and for the ozone research community, with a call for coordinated global action to protect the upper atmosphere environment. Actions that companies can take include measuring the emissions of launch vehicles on the test stand and in-situ during flight, making that data available to researchers, and putting effects on ozone into industry best-practise rocket design and development.

“The international ozone research community has a strong history of measuring atmospheric ozone and developing models to understand how human activities could impact this critical layer of our atmosphere. By working with launch providers, we are well-placed to figure out what impacts we might see”, says Dr Revell.

“Rockets have exciting potential to enable industrial-level access to near-Earth space, and exploration throughout the Solar System. Creating sustainable global rocket launches is going to take coordination across aerospace companies, scientists, and governments: it is achievable, but we need to start now,” says Dr Bannister. “This is our chance to get ahead of the game.”

 

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JOURNAL

Journal of the Royal Society of New Zealand

DOI

10.1080/03036758.2022.2152467 

METHOD OF RESEARCH

Literature review

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

Envisioning a sustainable future for space launches: a review of current research and policy

Mysterious brain activity in mice watching a movie could help tackle Alzheimer's, improve AI

Tracking the memory-making neuron’s activity in mice as they watch a classic film reveals novel ways to diagnose learning and memory disorders and improve AI

Peer-Reviewed Publication

UNIVERSITY OF CALIFORNIA - LOS ANGELES HEALTH SCIENCES

LOS ANGELES – Even the legendary filmmaker Orson Welles couldn’t have imagined such a plot twist.  

By showing Welles’s movie “Touch of Evil” to mice, Chinmay Purandare, PhD, and Prof. Mayank Mehta of UCLA have uncovered surprising and important new insights about how neurons form memories. The discovery points to new ways to diagnose Alzheimer’s and other learning and memory impairments, while also improving artificial intelligence. 

Mice were shown a short clip from the 1958 film noir classic “Touch of Evil” as scientists monitored their brain activity. This was a rather nondescript black-and-white, silent movie clip showing humans walking about. Textbook knowledge and conventional wisdom says that mice should not show interest in such a movie and nor should neurons in a part of their brain called the hippocampus, which is known to be crucial for learning and memory. When scientists looked inside this part of the mouse brain, they found that it only acts as “the GPS system of the brain” (as described in the 2014 Nobel Prize in Physiology or Medicine), which is unrelated to general learning, e.g. a conversation. This was a major obstacle in research on diagnosis of memory and on mechanisms of abstractions or AI.

However, the researchers made a blockbuster finding: There were surprising, but highly systematic bursts of activity in the hippocampus in response to this movie. Scientists could even reconstruct specific movie segments using these mysterious bursts from only a fraction of hippocampal neurons.  

The plot thickens even more. Even neurons in other parts of the brain (the primary visual cortex or the thalamus) that are commonly thought to encode simple features like vertical or horizontal lines responded far more robustly to the specific scenes of the movie than the textbook stimuli. In fact, every part of the brain that they investigated, from the simple visual to the GPS circuits, lit up robustly in response to specific movie scenes.

Mehta said the findings represent a “major paradigm shift” in how scientists can study mice’s ability to recall a specific experience or event – or what’s known as episodic memory. Mehta said this could help scientists address a missing component in research for memory diseases like Alzheimer’s.

“Although dozens of drugs have cured Alzheimer’s in mice, none have worked in humans,” Mehta said. “One reason is that the standard test of episodic learning and memory is spatial navigation in mice. However, Alzheimer’s patients have profound deficits in non-spatial memory too – e.g., a conversation or an event they witnessed, which is unrelated to GPS navigation.”

The authors say that focusing Alzheimer’s and other memory drugs in mice using only a spatial memory test doesn’t address whether the treatments improved the mice’s ability to remember most events or experiences that make up episodic memory. 

“It is a major challenge to create such events for mice that would closely mimic events familiar to humans. Hence, we turned to movies,” said Dr. Purandare, the study’s lead author. “By all textbook accounts, human movies should not generate any interpretable pattern in the mouse hippocampus.”

However, in the studies published in Nature in 2021 and 2022, these UCLA researchers found that neurons in the mice hippocampus responded to simple visual stimuli when mice explored virtual reality and this induced robust neuroplasticity. Therefore, they theorized it was possible to test episodic memory in mice by showing them a movie and monitoring activity in their hippocampus.

In this new study, nearly half of neurons in the rodent hippocampus encoded specific, small segments of the movie, signifying a remarkable response to the events on screen. The mundanity of the silent, black-and-white clip made the findings even more compelling, Mehta said. In fact, mice were also free to ignore the movie if they wanted to.

“If the hippocampus lights up with this mundane movie clip, without any memory demand, then we can safely conclude that it is not due to other things like expectation of reward or excitement,” Mehta said. “We were blown away by the massive responses despite the lack of these emotional components.”

Mehta said preliminary data indicated that making the scene richer by adding interesting elements for mice, like images of other animals, sounds, etc. could produce a stronger hippocampal response, creating an emotional response and vibrant episodic memories.

“Another major surprise, the visual areas did not care if the movie was played in a sequence, or in a scrambled order. But the hippocampal neurons did something very different – they did not respond at all to the scrambled movie,” Mehta said. “This shows that the hippocampal neurons are extracting episodic information from the incoming visual information that is agnostic to the episode.”

Mehta said the findings are also crucial for improving AI. “The hippocampus is at the apex of a deep neural network, with the eyes at the front end, followed by the thalamus, primary visual cortices and ending up in the hippocampus.” But, given the prevailing belief that the mouse hippocampus is “the GPS system,” experiments could either study the visual cortex or the hippocampus, but not both at the same time.

“Our findings open up the possibility to study all these brain areas simultaneously and determine how the brain creates an episode from a series of images falling on the retina,” Dr. Purandare said. “Selective and episodic activation of the mouse hippocampus using a human movie opens up the possibility of directly testing human episodic memory disorders and therapies using mouse neurons, a major step forward.”

The study appears in the journal eLife. It was supported by funding from the National Institute of Mental Health and research at the Allen Institute. The authors declared no competing interest.   

Dr. Purandare is now a postdoctoral scholar at UCSF. Mehta is a professor in the departments of Physics, Neurology, Electrical and Computer Engineering, and the director of Center for Physics of Life at UCLA.  

For more information about their research using immersive virtual reality for mice, visit https://www.physics.ucla.edu/~mayank/  

---

JOURNAL

eLife

SUBJECT OF RESEARCH

Animals

ARTICLE TITLE

Mega-scale movie-fields in the mouse visuo-hippocampal network

  

New technique maps large-scale impacts of fire-induced permafrost thaw in Alaska

Researchers combine active airborne lidar sensors, passive spaceborne optical sensors and machine learning

Peer-Reviewed Publication

FLORIDA ATLANTIC UNIVERSITY

 

IMAGE: THE PICTURE SHOWS THE RECOVERY OF VEGETATION FOR THE 2001 FIRE AND 2010 FIRE OVER TANANA FLATS LOWLAND PERMAFROST IN INTERIOR ALASKA WHERE THE STUDY WAS CONDUCTED. view more 

CREDIT: FLORIDA ATLANTIC UNIVERSITY

About 40 percent of interior Alaska is underlain by ice-rich permafrost – permanently frozen grounds made up of soil, gravel and sand – bound together by ice. Certain conditions, such as climate warming, have intensified tundra wildfires which have profound implications for permafrost thaw.

Surface vegetation plays a dominant role in protecting permafrost from summer warmth, so any alteration of vegetation structure, particularly following severe wildfires, can cause dramatic top–down thaw.

Severe wildfires remove the vegetation and surface soil organic matter, and the loss of this insulation increases the ground heat flux and promotes permafrost thaw. This thaw triggers ground sinking and thermokarst (ground-surface collapse from permafrost thaw) development and leads to surface water inundation, vegetation shifts, changes in soil carbon balance and carbon emissions, all impacting climate warming.

The permafrost–fire–climate system has been a hotspot in research for decades. The large-scale effects of these wildfires on land cover change, post-fire resilience, and subsequent thaw settlement remain unknown. Thaw settlement is difficult to measure as there are often no absolute reference frames to compare to the subtle, but widespread topographic change in permafrost landscapes.

Researchers from Florida Atlantic University, in collaboration with the United States Army Corps of Engineers Cold Regions Research & Engineering Laboratory, and Alaska Ecoscience, systematically analyzed the effects of six large fires that have occurred since 2000 on the Tanana Flats lowland in interior Alaska on land cover change, vegetation dynamics, and terrain subsidence, or sinking.

For the first time, they have developed a machine learning-based ensemble approach to quantify fire-induced thaw settlement across the entire Tanana Flats, which encompasses more than 3 million acres (approximately 1,250 km2). Researchers linked airborne repeat lidar data to time-series Landsat products (satellite images) to delineate thaw settlement patterns across the six fire scars. This novel approach helped to explain about 65 percent of the variance in lidar-detected elevation change.  

Study findings, published in Environmental Research Letters, showed that in total, the six fires resulted in a loss of nearly 99,000 acres (approximately 400 km2) of evergreen forest from 2000 to 2014 among nearly 155,000 acres (approximately 590 km2) of fire-influenced forests with varying degrees of burn severity. The fires provided favorable conditions for shrub-fen (low-growing shrubs) development, resulting in a comparable post-fire coverage of shrubland and evergreen forest and increasing encroachment of shrubland to areas with sparse vegetation.

Importantly, the researchers did not observe the regrowth of forests after 13 years of the oldest fire in 2001, based on Landsat observations.

“Our study has shown that linking airborne repeat lidar with Landsat products is an encouraging tool for large-scale quantification of fire-induced thaw settlement,” said Caiyun Zhang, Ph.D., senior author and a professor in the Department of Geosciences within FAU’s Charles E. Schmidt College of Science. “Because airborne lidar measurements are increasingly being made across northern permafrost regions, our method is a valuable means of projecting elevation change across entire fire scars within uniform permafrost-affected landscapes by using data-driven machine learning techniques.”

The Tanana Flats, which comprises more than 6 million acres (approximately 2,500 km2), is representative of the lowland landscape south of Fairbanks in interior Alaska. It consists of a complex mosaic of ice-rich permafrost and permafrost free ecosystems and is a hotbed for thermokarst. Much of the land is part of a military training area managed by the U.S. Department of Defense.

For the study, researchers assessed three commonly used machine learning algorithms including artificial neural network, support vector machine, and random forest for fire-induced thaw settlement modeling.

“Machine learning has been extensively applied for modeling in geosciences,” said Zhang. “The idea is that each algorithm has its pros and cons, and an ensemble analysis of comparative models can produce a more robust estimation than the application of a single model.”

Current and future projected increases in mean annual air temperature, the length of the summer growing season, and the severity and extent of wildfire are expected to lead to an increasingly dominant role of wildfire in permafrost ecosystems.

“Mapping thaw settlement as a result of wildfires is critical since it is associated with subsequent thermokarst development, snow accumulation, hydrology, vegetation shifts, and commensurate changes in the land-atmospheric exchange of water, energy, and greenhouse gases,” said Zhang. “The combination of active airborne lidar sensors with passive spaceborne optical sensors will enable scientists to measure widespread and large areas affected by wildfires in cold regions, especially with climate warming and increased fire events.”

This research was funded by the U.S. Army Corps of Engineers, Engineer Research and Development Center Applied Research Program Office for Installations and Operational Environment and Basic Research Program (PE 0601102/AB2), the U.S. Department of Defense’s Strategic Environmental Research and Development Program (projects RC2110 and RC18-1170), and the U.S. Department of Energy, Office of Science, Environmental System Science program (0000260300). 

Study co-authors are Thomas A. Douglas, Ph.D., a research chemist and senior scientist, U.S. Army Cold Regions Research & Engineering; David Brodylo, a Ph.D. student in FAU’s Department of Geosciences; and M. Torre Jorgenson, Alaska Ecoscience.  

- FAU -

About Florida Atlantic University:
Florida Atlantic University, established in 1961, officially opened its doors in 1964 as the fifth public university in Florida. Today, the University serves more than 30,000 undergraduate and graduate students across six campuses located along the southeast Florida coast. In recent years, the University has doubled its research expenditures and outpaced its peers in student achievement rates. Through the coexistence of access and excellence, FAU embodies an innovative model where traditional achievement gaps vanish. FAU is designated a Hispanic-serving institution, ranked as a top public university by U.S. News & World Report and a High Research Activity institution by the Carnegie Foundation for the Advancement of Teaching. For more information, visit www.fau.edu.

  

Image shows the mapped thaw settlement caused by the fires (a) and estimated uncertainty caused by different models (b).

  

Image shows the burn severity across six fire scars (a), and vegetation change before (c) and after (b) the fires.

CREDIT

Florida Atlantic University

JOURNAL

Environmental Research Letters

DOI

10.1088/1748-9326/acabd6 

METHOD OF RESEARCH

Computational simulation/modeling

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

Linking repeat lidar with Landsat products for large scale quantification of fire-induced permafrost thaw settlement in interior Alaska

Number of fires in Brazilian Amazon in August-September 2022 was highest since 2010

A Brazilian study identified more than 74,000 active fires in the period. Half of the Amazon is typically vulnerable to fire in period analyzed. Human action was the main cause of the recent destruction.

Peer-Reviewed Publication

FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO

 

IMAGE: HALF OF THE AMAZON IS TYPICALLY VULNERABLE TO FIRE IN THE TWO-MONTH PERIOD ANALYZED. HUMAN ACTION WAS THE MAIN CAUSE OF THE RECENT DESTRUCTION view more 

CREDIT: GABRIEL DE OLIVEIRA/UNIVERSITY OF SOUTH ALABAMA

The number of active fires recorded in the Brazilian Amazon in August-September 2022 was the highest since 2010, according to an article published in the journal Nature Ecology & Evolution. Besides the record number of fires (74,398), the researchers found they were due not to extreme drought, as in 2010, but to recent deforestation by humans.

“The idea of publishing our findings came up when we analyzed data provided free of charge by the Queimadas program,” said Guilherme Mataveli, first author of the article. Queimadas in Portuguese means burnings, and he was referring to the forest fire monitoring service run by the National Space Research Institute (INPE). Mataveli is currently a postdoctoral researcher in INPE’s Earth Observation and Geoinformatics Division and has a scholarship from FAPESP. 

The number of fires typically rises every year in August and September, when the weather favors fire in about half of the Amazon. “But the surge in the number of fires in 2010 was due to an extreme drought event that occurred in a large part of the region, whereas nothing similar occurred in 2022, so other factors must have been to blame,” Mataveli said.

Mataveli’s main research interest is the influence of land use and land cover on emissions of fine particulate matter from fire in the Amazon and Cerrado biomes using modeling and remote sensing.

The researchers also analyzed the locations of the fires detected using data provided free of charge by another INPE platform, TerraBrasilis. Their analysis showed that 62% occurred in recently deforested areas; that the number of fires in recently deforested areas in August-September 2022 rose 71% compared with the same period of 2021; and that the total deforested area increased by 64% according to the deforestation alerts issued by INPE’s real-time detection system (DETER).

“Alarming results also emerged from our analysis of the type of land on which these fires occurred, classified into public land, smallholdings, and medium to large private properties,” Mataveli said. More than a third (35%) of the fires detected in August-September 2022 occurred in public areas such as conservation units and Indigenous reservations, and the number of fires in these areas rose 69% year over year. 

“The Amazon has become more vulnerable to grilagem [land grabbing via falsification of title deeds] in recent years, and this sharp increase is one of the results of this process,” he said.

A key source of information for this land use and land cover analysis was TerraBrasilis, much of whose data comes from the Rural Environmental Register (CAR), designed to ensure compliance with the Forest Code. All landowners and land users are required to register with the CAR. The process is essentially self-declaratory, with the landowner entering environmental information about the property. Registration with the CAR is not required for conservation units, Indigenous reservations and other types of public land.

Climate goals

The advance of fire, deforestation, degradation, illegal mining and land grabbing in the Amazon runs counter to the goals established internationally by Brazil as part of its commitment to combat global warming, such as stopping all illegal deforestation by 2028 and achieving a 50% reduction in greenhouse gas emissions by 2030 compared to 2005 levels.

Besides the negative effect on biodiversity and maintenance of the ecosystem services essential to human life, such as climate regulation, the Brazilian economy is endangered by uncontrolled deforestation and associated activities. Markets for its exports of commodities, such as the European Union, are in the process of approving new regulatory standards that will prevent the purchase of goods produced in deforested or degraded areas.

“The article highlights a systemic problem that must be seriously addressed by society. A reversal of this trend requires punishment of those who break the law, implementation of efficient public policies, communication with society, and a search for alternative solutions based on cutting-edge science and capable of promoting sustainable development in the region. Identifying and prosecuting the people who are illicitly destroying the world’s largest tropical forest is one of the challenging tasks on the environmental agenda to be faced by the incoming federal government,” said Luiz Aragão, last author of the article. 

The other authors are Luciana Vanni Gatti and Nathália Carvalho, both researchers at INPE; Liana Oighenstein Anderson at the National Centre for Monitoring and Early Warnings of Natural Disasters (CEMADEN); Gabriel de Oliveira at the University of South Alabama (USA); Celso H. L. Silva-Junior at the University of California Los Angeles (UCLA) and California Institute of Technology (Caltech) in the United States, and the Federal University of Maranhão in Brazil; and Scott C. Stark at Michigan State University (MSU).

Aragão, Anderson and Gatti are also supported in their research by funding from FAPESP.

About São Paulo Research Foundation (FAPESP)

The São Paulo Research Foundation (FAPESP) is a public institution with the mission of supporting scientific research in all fields of knowledge by awarding scholarships, fellowships and grants to investigators linked with higher education and research institutions in the State of São Paulo, Brazil. FAPESP is aware that the very best research can only be done by working with the best researchers internationally. Therefore, it has established partnerships with funding agencies, higher education, private companies, and research organizations in other countries known for the quality of their research and has been encouraging scientists funded by its grants to further develop their international collaboration. You can learn more about FAPESP at www.fapesp.br/en and visit FAPESP news agency at www.agencia.fapesp.br/en to keep updated with the latest scientific breakthroughs FAPESP helps achieve through its many programs, awards and research centers. You may also subscribe to FAPESP news agency at http://agencia.fapesp.br/subscribe.

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JOURNAL

Nature Ecology & Evolution

DOI

10.1038/s41559-022-01945-2 

ARTICLE TITLE

Record-breaking fires in the Brazilian Amazon associated with uncontrolled deforestation