New fossil shows four-legged fishapod that returned to the water while Tiktaalik ventured onto land

Researchers discover a new fossil that is closely related to other animals that made the transition to land, but with features more suited for swimming and life in the water

Peer-Reviewed Publication

UNIVERSITY OF CHICAGO

 

IMAGE: ILLUSTRATION OF QIKIQTANIA WAKEI (CENTER) IN THE WATER WITH ITS LARGER COUSING, TIKTAALIK ROSEAE view more 

CREDIT: ALEX BOERSMA

A meme has been circulating online during the pandemic featuring Tiktaalik roseae, the iconic, four-legged “fishapod” that first made the transition from water to land 375 million years ago. Most variations show Tiktaalik poking its head out of the water and ready to crawl ashore, while an out of frame hand threatens it with a rolled-up newspaper or a stick. The joke is that those of us exhausted by the modern world wish we could go back in time, shoo it back into the water, and stop evolution in its tracks, sparing ourselves the present day of war, pestilence, and internet memes.

As it turns out, one of Tiktaalik’s close relatives did just that, opting to return to living in open water instead of venturing onto land. A new study from the laboratory of Neil Shubin, PhD, who co-discovered Tiktaalik in 2004, describes a fossil species that closely resembles Tiktaalik but has features that made it more suited to life in the water than its adventurous cousin. Qikiqtania wakei was small—just 30 inches long—compared to Tiktaalik, which could grow up to nine feet. The new fossil includes partial upper and lower jaws, portions of the neck, and scales. Mostly importantly, it also features a complete pectoral fin with a distinct humerus bone that lacks the ridges that would indicate where muscles and joints would be on a limb geared toward walking on land. Instead, Qikiqtania’s upper arm was smooth and curved, more suited for a life paddling underwater.  The uniqueness of the arm bones of Qikiqtania suggest that it returned to paddling the water after its ancestors began to use their appendages for walking.

“At first we thought it could be a juvenile Tiktaalik, because it was smaller and maybe some of those processes hadn’t developed yet,” Shubin said. “But the humerus is smooth and boomerang shaped, and it doesn’t have the elements that would support it pushing up on land. It’s remarkably different and suggests something new.”

The paper, “A New Elpistostegalian from the Late Devonian of the Canadian Arctic and the diversity of stem tetrapods,” was published July 20, 2022, in Nature.

A prehistoric pandemic project

Shubin, who is the Robert R. Bensley Distinguished Service Professor of Organismal Biology and Anatomy at the University of Chicago, found the fossil days before Tiktaalik was discovered, at a site about one mile east on southern Ellesmere Island in the territory of Nunavut in northern Arctic Canada. The name Qikiatania comes from the Inuktitut word Qikiqtaaluk or Qikiqtani, the traditional name for the region where the fossil site is located. The species designation wakei is in memory of the late David Wake, an eminent evolutionary biologist from the University of California at Berkeley.

Shubin and his field partner, Ted Daeschler, PhD, from the Academy of Natural Sciences of Drexel University, collected the specimens from a quarry after spotting a few promising looking rocks with distinctive, white scales on the surface. But they sat in storage, mostly unexamined, while the team focused on preparing Tiktaalik.

Fifteen years later, the discovery of Qikiqtania became another pandemic story. Postdoctoral researchers Justin Lemberg, PhD, and Tom Stewart, PhD, CT-scanned one of the larger rock specimens in March 2020 and realized that it contained a pectoral fin. Unfortunately, it was too deep inside the rock to get a high-resolution image, and they couldn’t do much more with it once the pandemic forced labs to close.

"We were trying to collect as much CT-data of the material as we could before the lockdown, and the very last piece we scanned was a large, unassuming block with only a few flecks of scales visible from the surface,” said Lemberg, who is now doing cultural resource management fieldwork in Southern California. “We could hardly believe it when the first, grainy images of a pectoral fin came into view. We knew we could collect a better scan of the block if we had the time, but that was March 13th, 2020, and the University shut down all non-essential operations the following week."

In the summer of 2020 when campus facilities reopened, they contacted Mark Webster, PhD, Associate Professor of Geophysical Sciences, who had access to a saw that could trim pieces off the specimen so that a CT scanner could get closer and produce a better image. Stewart and Lemberg carefully marked the boundaries on the block and arranged an exchange outside their lab in Culver Hall. The resulting images revealed a nearly complete pectoral fin and upper limb, including the distinctive humerus bone.

“That’s what blew our minds,” Shubin said. “This was by no means a fascinating block at first, but we realized during the COVID lockdown when we couldn’t get in the lab that the original scan wasn’t good enough and we needed to trim the block. And when we did, look at what happened. It gave us something exciting to work on during the pandemic. It’s a fabulous story.”

Glimpses into vertebrate history

Qikiqtania is slightly older than Tiktaalik but not by much. The team’s analysis of where it sits on the tree of life places it, like Tiktaalik, adjacent to the earliest creatures known to have finger-like digits. But even though Qikiqtania’s distinct pectoral fin was more suited for swimming, it wasn’t entirely fish-like either. Its curved paddle shape was a distinct adaptation, different from the jointed, muscled legs or fan-shaped fins we see in tetrapods and fish today.

We tend to think animals evolved in a straight line that connects their prehistoric forms to some living creature today, but Qikiqtania shows that some animals stayed on a different path that ultimately didn’t work out. Maybe that’s a lesson for those wishing Tiktaalik had stayed in the water with it.

“Tiktaalik is often treated as a transitional animal because it’s easy to see the stepwise pattern of changes from life in the water to life on land. But we know that in evolution things aren’t always so simple,” said Stewart, who will be joining the faculty at Penn State University this summer. “We don’t often get glimpses into this part of vertebrate history. Now we’re starting to uncover that diversity and to get a sense of the ecology and unique adaptations of these animals. It’s more than simple transformation with just a limited number of species.”

The research was supported by the Brinson Foundation, the Academy of Natural Sciences of Drexel University, the University of Chicago Biological Sciences Division, the Polar Continental Shelf Program of Natural Resources Canada, the Nunavut Department of Culture and Heritage, the Hamlet of Grise Fiord and its Iviq Hunters and Trappers Association, and the National Science Foundation.

Qiqiktania video 1 [VIDEO] | EurekAlert! Science News Releases

Qiqiktania video 2 [VIDEO] | EurekAlert! Science News Releases

CAPTION

Tom Stewart, PhD, Assistant Professor of Biology at Penn State University, holds the fossil specimen of Qikiqtania wakei

CREDIT

Tom Stewart

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JOURNAL

Nature

DOI

10.1038/s41586-022-04990-w 

METHOD OF RESEARCH

Imaging analysis

SUBJECT OF RESEARCH

Animals

ARTICLE TITLE

A new elpistostegalian from the Late Devonian of the Canadian Arctic

ARTICLE PUBLICATION DATE

20-Jul-2022

Human eggs remain healthy for decades by putting ‘batteries on standby mode’

Researchers at the CRG have solved how oocytes remain dormant without losing their reproductive capacity. The findings are reported in the journal Nature.

Peer-Reviewed Publication

CENTER FOR GENOMIC REGULATION

 

IMAGE: LIVE CELL IMAGING OF HUMAN FOLLICLE, SHOWING GRANULOSA CELLS ON THE OUTER LAYER, WHICH SUPPORT THE OOCYTE, CONTAINED WITHIN. THE ACTIVITY OF REACTIVE OXYGEN SPECIES IS SHOWN IN RED. THE RESEARCHERS OBSERVED ROS ACTIVITY IN THE GRANULOSA CELLS BUT IT IS VIRTUALLY ABSENT IN THE OOCYTE. view more 

CREDIT: AIDA RODRIGUEZ/NATURE

Immature human egg cells skip a fundamental metabolic reaction thought to be essential for generating energy, according to the findings of a study by researchers at the Centre for Genomic Regulation (CRG) published today in the journal Nature.

By altering their metabolic activity, the cells avoid creating reactive oxygen species, harmful molecules that can accumulate, damage DNA and cause cell death. The findings explain how human egg cells remain dormant in ovaries for up to 50 years without losing their reproductive capacity.

“Humans are born with all the supply of egg cells they have in life. As humans are also the longest-lived terrestrial mammal, egg cells have to maintain pristine conditions while avoiding decades of wear-and-tear. We show this problem is solved by skipping a fundamental metabolic reaction that is also the main source of damage for the cell. As a long-term maintenance strategy, its like putting batteries on standby mode. This represents a brand new paradigm never before seen in animal cells,” says Dr. Aida Rodriguez, postdoctoral researcher at the CRG and first author of the study.

Human eggs are first formed in the ovaries during foetal development, undergoing different stages of maturation. During the early stages of this process, immature egg cells known as oocytes are put into cellular arrest, remaining dormant for up to 50 years in the ovaries. Like all other eukaryotic cells, oocytes have mitochondria – the batteries of the cell – which they use to generate energy for their needs during this period of dormancy.

Using a combination of live imaging, proteomic and biochemistry techniques, the authors of the study found that mitochondria in both human and Xenopus oocytes use alternative metabolic pathways to generate energy never before seen in other animal cell types.

A complex protein and enzyme known as complex I is the usual ‘gatekeeper’ that initiates the reactions required to generate energy in mitochondria. This protein is fundamental, working in the cells that constitute living organisms ranging from yeast to blue whales. However, the researchers found that complex I is virtually absent in oocytes. The only other type of cell known to survive with depleted complex I levels are all the cells that make up the parasitic plant mistletoe.

According to the authors of the study, the research explains why some women with mitochondrial conditions linked to complex I, such as Leber’s Hereditary Optic Neuropathy, do not experience reduced fertility compared to women with conditions affecting other mitochondrial respiratory complexes.

The findings could also lead to new strategies that help preserve the ovarian reserves of patients undergoing cancer treatment. “Complex I inhibitors have previously been proposed as a cancer treatment. If these inhibitors show promise in future studies, they could potentially target cancerous cells while sparing oocytes,” explains Dr. Elvan Böke, senior author of the study and Group Leader in the Cell & Developmental Biology programme at the CRG.

Oocytes are vastly different to other types of cells because they have to balance longevity with function. The researchers plan to continue this line of research and uncover the energy source oocytes use during their long dormancy in the absence of complex I, with one of the aims being to understand the effect of nutrition on female fertility.

“One in four cases of female infertility are unexplained – pointing to a huge gap of knowledge in our understanding of female reproduction. Our ambition is to discover the strategies (such as the lack of complex I ) oocytes employ to stay healthy for many years in order to find out why these strategies eventually fail with advanced age” concludes Dr. Böke.

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JOURNAL

Nature

DOI

10.1038/s41586-022-04979-5 

METHOD OF RESEARCH

Experimental study

SUBJECT OF RESEARCH

Human tissue samples

ARTICLE TITLE

Oocytes maintain ROS-free mitochondrial metabolism by suppressing complex I

ARTICLE PUBLICATION DATE

20-Jul-2022

Making a memory positive or negative

Salk researchers pinpoint a neurotransmitter that helps assign positive or negative emotions to a memory

Peer-Reviewed Publication

SALK INSTITUTE

 

IMAGE: EXPRESSION OF VARIOUS GENES AND PROTEINS (WHITE, RED, AND GREEN) IN NEURONS AMONGST MOUSE BRAIN CELLS (BLUE). view more 

CREDIT: SALK INSTITUTE

LA JOLLA—(July 20, 2022) Researchers at the Salk Institute and colleagues have discovered the molecule in the brain responsible for associating good or bad feelings with a memory. Their discovery, published in Nature on July 20, 2022, paves the way for a better understanding of why some people are more likely to retain negative emotions than positive ones—as can occur with anxiety, depression or post-traumatic stress disorder (PTSD).

“We’ve basically gotten a handle on the fundamental biological process of how you can remember if something is good or bad,” says senior author Kay Tye, a professor in Salk’s Systems Neurobiology Laboratory and a Howard Hughes Medical Institute Investigator. “This is something that’s core to our experience of life, and the notion that it can boil down to a single molecule is incredibly exciting.”

For a human or animal to learn whether to avoid, or seek out, a particular experience again in the future, their brain must associate a positive or negative feeling, or “valence” with that stimulus. The brain’s ability to link these feelings with a memory is called “valence assignment.”

In 2016, Tye discovered that a group of neurons in the brain’s basolateral amygdala (BLA) helps assign valence when mice are learning. One set of BLA neurons was activated with positive valence, as the animals learned to associate a tone with a sweet taste. A separate set of BLA neurons was activated with negative valence, as the animals learned to associate a different tone with a bitter taste.

“We found these two pathways—analogous to railroad tracks—that were leading to positive and negative valence, but we still didn’t know what signal was acting as the switch operator to direct which track should be used at any given time,” says Tye, holder of the Wylie Vale Chair.

In the new study, the researchers homed in on the importance of the signaling molecule neurotensin to these BLA neurons. They already knew that neurotensin is a neuropeptide produced by the cells associated with valence processing, but so are a few other neurotransmitters. So, they used CRISPR gene editing approaches to selectively remove the gene for neurotensin from the cells—the first time that CRISPR has been used to isolate specific neurotransmitter function.

Without neurotensin signaling in the BLA, mice could no longer assign positive valence and didn’t learn to associate the first tone with a positive stimulus. Interestingly, the absence of neurotensin did not block negative valence. The animals instead became even better at negative valence, having a stronger association between the second tone and a negative stimulus.

The findings suggest that the brain’s default state is to have a bias toward fear—the neurons associated with negative valence are activated until neurotensin is released, switching on the neurons associated with positive valence. From an evolutionary perspective, Tye says, this makes sense because it helps people avoid potentially dangerous situations—and it probably resonates with people who tend to find the worst in a situation.

CAPTION

From left: Kay Tye and Hao Li

CREDIT

Salk Institute

In further experiments, Tye and her team showed that high levels of neurotensin promoted reward learning and dampened negative valence, further supporting the idea that neurotensin is responsible for positive valence.

“We can actually manipulate this switch to turn on positive or negative learning,” says co-first author Hao Li, a postdoctoral fellow in the Tye Lab. “Ultimately, we’d like to try to identify novel therapeutic targets for this pathway.”

The researchers still have questions about whether levels of neurotensin can be modulated in people’s brains to treat anxiety or PTSD. They are also planning future studies to probe what other brain pathways and molecules are responsible for triggering the release of neurotensin.

Other authors of the paper were Matilde Borio, Mackenzie Lemieux, Austin Coley, Avraham Libster, Aneesh Bal, Caroline Jia, Jasmin Revanna, Kanha Batra, Kyle Fischer, Laurel Keyes, Nancy Padilla-Coreano and Romy Wichmann of Salk; Praneeth Namburi, Jacob Olson, Anna Beyeler, Gwendolyn Calhoon, Natsuko Hitora-Imamura, Ada Felix-Ortiz, Verónica de la Fuente, Vanessa Barth, Hunter King, Ehsan Izadmehr, Cody Siciliano and Ila Fiete of MIT; Xin Jin, Sourav Choudhury, Xi Shi and Feng Zhang of the Broad Institute of MIT and Harvard; Huan Wang and Yulong Li of Peking University; and Kenneth McCullough and Kerry Ressler of Harvard Medical School.

The work was supported by the JPB Foundation, PIIF, PNDRF, JFDP, Alfred P. Sloan Foundation, New York Stem Cell Foundation, Klingenstein Foundation, McKnight Foundation, Clayton Foundation, National Institutes of Health (R01-MH102441, RF1-AG047661, DP2-DK102256, DP1-AT009925, F32 MH115446-01 and K99 DA055111), the Brain and Behavior Research Foundation, MEXT (15K21744, 17H06043), the Uehara Memorial Foundation, Singleton, Leventhal and Whitaker fellowships, a fellowship from the Swiss National Science Foundation and a Fulbright scholarship.

About the Salk Institute for Biological Studies:

Every cure has a starting point. The Salk Institute embodies Jonas Salk’s mission to dare to make dreams into reality. Its internationally renowned and award-winning scientists explore the very foundations of life, seeking new understandings in neuroscience, genetics, immunology, plant biology and more. The Institute is an independent nonprofit organization and architectural landmark: small by choice, intimate by nature and fearless in the face of any challenge. Be it cancer or Alzheimer’s, aging or diabetes, Salk is where cures begin. Learn more at: salk.edu.

VIDEO Making a memory positive or ne [VIDEO] | EurekAlert! Science News Releases

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JOURNAL

Nature

DOI

10.1038/s41586-022-04964-y 

ARTICLE TITLE

Neurotensin orchestrates valence assignment in the amygdala

ARTICLE PUBLICATION DATE

20-Jul-2022

Burning woody biomass in power plants could reduce carbon

Peer-Reviewed Publication

UNIVERSITY OF GEORGIA

According to a new study by researchers in the University of Georgia’s Warnell School of Forestry and Natural Resources, replacing coal in Georgia’s power plants with woody biomass could not only meet Georgia’s power needs, but reduce carbon emissions.

The research calculated both economic and environmental factors to provide a comprehensive picture of the impact of replacing coal with timber for a 50-year period.

As one of the largest consumers of coal in the Southeast, Georgia burns over 7 million tons each year. This accounts for nearly two-thirds of all carbon emissions from Georgia’s power sector. Replacing coal with another fuel source could reduce those emissions by 43%, according to Farhad Hossain Masum, a Ph.D. graduate and first author of the study.

Masum’s research started in 2017 when he began looking for a suitable feedstock to replace coal in power plants. Early on, the research showed that woody biomass, like wood chips and the residue from logging, could be more economical and better for the environment than other renewable fuel sources.

“Torrefied pulpwood and logging residue can be used in coal-fired power plants without making major upgrades to the plant. This makes it a great alternative to coal, especially in forest-rich southern states,” said Puneet Dwivedi, an associate professor at Warnell School, Masum’s advisor and co-author of the study.

The torrefaction of wood is like roasting coffee. Wood is heated in a controlled environment, usually around 400 degrees Fahrenheit. The heat removes moisture and chemically alters the wood. This process reduces the biomass of the wood by around 25%, turns it into a charcoal-like substance, and gives it a similar energy density to coal.

“Based on previous research, we knew this could work, but we weren’t sure of the best way to add torrefied wood as a fuel source. We looked at a few different models to see what would happen if we implemented these programs across Georgia,” said Masum.

First, they quantified the impact of making no changes and continuing to burn coal. Second, they studied using pulpwood as a fuel source; a portion of trees usually with trunks ranging from 5 to 9 inches in diameter. Third, they measured the impact of using both pulpwood and logging residues to replace coal.

They found the third scenario, using both pulpwood and logging residues, would be the most carbon-efficient way to generate electricity for Georgia. This method could reduce 43% of carbon emissions from coal-fired power plants without major upgrades to the facilities.

However, it would require an additional 100,000 acres of forestland to be harvested each year. In the scenario, these trees would be harvested from six southern states.

This is still more efficient than using only pulpwood, according to the researchers. If only pulpwood was used to manufacture the torrefied wood chips, an additional 340,000 acres of forestland would need to be harvested annually to replace Georgia’s coal.

“Our results indicate that Georgia and Alabama could supply most of the additional wood required for biopower generation,” said Masum.

Even though more trees would need to be cut to replace coal, the research showed that this would benefit the environment by keeping carbon out of the atmosphere. Coal releases significantly more non-renewable carbon than torrefied wood when burned. In general, this carbon can be considered extra carbon that was not in the environment but sequestered underground.

On the other hand, trees soak up carbon from the atmosphere as they grow. While some of this carbon may be re-released, it results in a net reduction of carbon from the atmosphere. This reduction was the highest when both pulpwood and logging residues replaced coal for electricity generation.

Integrating logging residues into the energy supply chain would also allow foresters to make better use of every part of the tree. Currently, most logging residue in the southeast is left in the field and burned.

“The use of wood-based electricity will not only reduce the carbon footprint of the state, but it will potentially create local jobs, boost forest health, increase the income of rural households, and ensure the flow of forest-based ecosystem services,” said Dwivedi.

“However, a need exists to evaluate the economic and welfare impacts of any initiative to replace coal-based power generation in Georgia to tackle issues operating at the interface of energy access and climate change.”

Co-authors include Weiwei Wang of the Nanjing University of Information Science and Technology in Nanjing, China, and Greg Colson in the Department of Agricultural and Applied Economics at the University of Georgia. The research was supported by a McIntire-Stennis grant from the United States Department of Agriculture.

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JOURNAL

Journal of Environmental Management

DOI

10.1016/j.jenvman.2022.115060 

ARTICLE TITLE

Replacing coal in Georgia's power plants with woody biomass to increase carbon benefit: A mixed integer linear programming model

A history of rye: How early farmers made plants genetically less flexible

Peer-Reviewed Publication

MARTIN-LUTHER-UNIVERSITÄT HALLE-WITTENBERG

 

IMAGE: DOMESTICATED RYE GROWN IN HALLE (SAALE), GERMANY view more 

CREDIT: UNI HALLE / STEVEN DREISSIG

Over the course of many thousands of years, humans turned rye into a cultivated plant. In doing so, they have considerably limited its genetic flexibility. Today, wild rye not only has a more diverse genetic make-up, it is able to recombine this more freely than its domesticated cousins. A research team led by Martin Luther University Halle-Wittenberg (MLU) and the Leibniz Institute of Plant Genetics and Crop Plant Research (IPK) has demonstrated this in a new study published in the scientific journal "Molecular Biology and Evolution". The results also explain why cultivated rye is less resistant than wild species to developments such as climate change.

In their study, the team investigated various properties and the genetic material of 916 wild and domesticated rye plants from different regions in Europe and Asia. They were particularly interested in the so-called recombining regions of rye. In essence, this describes how often the genetic material within a plant mixes along a chromosome during cell division. "The process of recombination plays an important role in a species’ evolution because it enables two beneficial gene variants to combine," explains Dr Steven Dreissig from MLU. At the same time, useful variants can also be separated from ones that are less beneficial. The larger the recombination landscape, the more plants are able to flexibly recombine their genetic material.

For early farmers, however, this process was disadvantageous: agriculture relies on uniform plants with more or less there the same properties and the same genetic material. In the case of rye, says Dreissig, the situation is aggravated by the fact that the plants depend on cross-pollination; unlike barley or wheat, they are unable to self-pollinate. "Rye pollen can travel up to several kilometres. This allows populations that are separated spatially to remain in contact and exchange genetic material," says Dreissig.

People started growing cereals, such as barley or wheat, around 12,000 years ago. Most of the varieties established today originated in the Fertile Crescent region of the Middle East. "Rye is assumed to have first spread to Europe as a weed and could only be domesticated there much later because there were no disturbing wild varieties," says Dr Martin Mascher from IPK, who is also a member of the German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig.

Their new analyses have allowed the researchers to reconstruct the distribution of rye and recreate a kinship network from Asia to Central Europe. The wider the distance between the individual locations, the greater the differences in the recombination landscape of the plants. "We actually found major differences between domesticated and wild rye, especially in the non-recombining regions. In cultivated rye, the recombining regions are significantly smaller than in the weed-like plants, such as those still found today in Turkey," says Dreissig. This is advantageous for cultivated plants because it makes plants with desirable properties, for example firm ears and large grains, more uniform and controllable. Wild rye, on the other hand, benefits from this genetic flexibility, which allows it to react better to disturbance factors, such as a changing climate.

The team also identified a gene region that appears to play a major role in the flexibility of the genetic material. In doing so, they also found a gene that was already known to influence recombining regions in yeast.

 

The study was funded by the Deutsche Forschungsgemeinschaft (German Research Foundation, DFG) and the Federal Ministry of Education and Research (BMBF).

 

Study: Schreiber M. et al. Recombination Landscape Divergence Between Populations is Marked by Larger Low-Recombining Regions in Domesticated Rye. Molecular Biology and Evolution (2022). doi: 10.1093/molbev/msac131

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JOURNAL

Molecular Biology and Evolution

DOI

10.1093/molbev/msac131 

METHOD OF RESEARCH

Observational study

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

Recombination Landscape Divergence Between Populations is Marked by Larger Low-Recombining Regions in Domesticated Rye

Human activities increase likelihood of more extreme heatwaves, researchers find

Peer-Reviewed Publication

INSTITUTE OF ATMOSPHERIC PHYSICS, CHINESE ACADEMY OF SCIENCES

 

IMAGE: SHADING REPRESENTS SURFACE AIR TEMPERATURE ANOMALIES, AND THE GREEN VECTOR DENOTES JETSTREAM (A NARROW BAND OF VERY STRONG WESTERLY AIR CURRENTS NEAR THE ALTITUDE OF THE TROPOPAUSE). TWO BLUE VECTORS INDICATE THAT THE HEATWAVE IS RELATED TO ANOMALOUS CIRCULATIONS IN THE NORTH PACIFIC AND THE ARCTIC. view more 

CREDIT: JIAYU ZHENG

July 19 was the hottest day ever recorded in the United Kingdom, with temperatures surpassing 40 degrees Celsius (about 104 degrees Fahrenheit). The heatwave serves as an early preview of what climate forecasters theorized will be typical summer weather in the U.K. in 2050. The heat continues across Europe today, as well as in the United States, where more than a third of the country is under heat warnings.

The temperatures harken back to just over a year ago when nearly 1,500 people died during a late June heatwave that more than doubled average temperatures in the United States and Canada.

Will temperatures continue to rise, leading to more frequent extreme heat events?

Yes, according to the latest analysis of the atmospheric circulation patterns and human-caused emissions that led to the 2021 heatwave in North America. The findings, published on July 22 in Advances in Atmospheric Sciences, may also explain the U.K.'s current heatwave.

The research team found that greenhouse gases are the primary reason for increased temperatures in the past and will likely continue to be the main contributing factor, with simulations showing that extreme heatwave events will increase by more than 30% in the coming years. Almost two-thirds of that increased probability is the result of greenhouse gases, according to their results.

“An extraordinary and unprecedented heatwave swept western North America in late June of 2021, resulting in hundreds of deaths and a massive die-off of sea creatures off the coast as well as horrific wildfires,” said co-corresponding author Chunzai Wang, a researcher in the Southern Marine Science and Engineering Guangdong Laboratory and head of the State Key Laboratory of Tropical Oceanography at the South China Sea Institute of Oceanology, Chinese Academy of Sciences (CAS).

“In this paper, we studied the physical processes of internal variability, such as atmospheric circulation patterns, and external forcing, such as anthropogenic greenhouse gases.”

Atmospheric circulation patterns describe how air flows and influences surface air temperatures around the planet, both of which can change based on natural warming from the Sun and atmospheric internal variability, as well as Earth’s rotation. These configurations are responsible for daily weather, as well as the long-term patterns comprising climate. . Using observational data and climate models, the researchers identified that three atmospheric circulation patterns co-occurred during the 2021 heatwave: the North Pacific pattern, the Arctic-Pacific Canada pattern and the North America pattern.

“The North Pacific pattern and the Arctic-Pacific Canada pattern co-occurred with the development and mature phases of the heatwave, whereas the North America pattern coincided with the decaying and eastward movements of the heatwave,” Wang said. “This suggests the heatwave originated from the North Pacific and the Arctic, while the North America pattern ushered the heatwave out.”

But atmospheric circulation patterns can co-occur — and have before — without triggering an extreme heatwave, so how much was the 2021 event influenced by human activities? Wang and the team used the internationally curated, tested and assessed models from the World Climate Research Programme, specifically the Detection Attribution Model Comparison models of the Coupled Model Intercomparison Project Phase 6 (CMIP6).

“From the CMIP6 models, we found that it is likely that global warming associated with greenhouse gases influences these three atmospheric circulation pattern variabilities, which, in turn, led to a more extreme heatwave event,” Wang said. “If appropriate measures are not taken, the occurrence probability of extreme heatwaves will increase and further impact the ecological balance, as well as sustainable social and economic development.”

Other contributors include co-corresponding author Jiayu Zheng and two students from the University of CAS: Wei Lin and Yuqing Wang.

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JOURNAL

Advances in Atmospheric Sciences

DOI

10.1007/s00376-022-2078-2 

ARTICLE TITLE

Unprecedented Heatwave in Western North America during Late June of 2021: Roles of Atmospheric Circulation and Global Warming

ARTICLE PUBLICATION DATE

22-Jul-2022

Preterm birth is more likely with exposure to phthalates

Rutgers contributes to a National Institutes of Health study of pregnant women confirming link with chemicals that could put pregnancy at risk

Peer-Reviewed Publication

RUTGERS UNIVERSITY

A Rutgers researcher was part of a National Institutes of Health study that found pregnant women who were exposed to chemical compounds known as phthalates during pregnancy had an increased risk of preterm birth.

Phthalates are industrial chemicals used in personal-care products, such as cosmetics, as well as solvents, detergents and in food packaging.

After examining data from 6,045 pregnant women in the U.S., researchers found that women with higher concentrations of several phthalate metabolites in their urine were more likely to deliver their babies preterm—or delivering three or more weeks before a mother’s due date. The study was published in the journal JAMA Pediatrics.

“Preterm birth is one of the most poorly understood, intractable challenges in maternal-child health,” said author Emily Barrett, an associate professor at the Rutgers School of Public Health and a member of the Environmental and Occupational Health Sciences Institute.

“This study provides compelling evidence that everyday chemicals in our environment are part of the problem,” Barrett said. Conducting the largest study in the United States to date on this topic, researchers pooled data from 16 studies conducted throughout the U.S. that had individual participant data on prenatal urinary phthalate metabolites (which represent exposure to phthalates) as well as the timing of delivery of the study participants. Pregnant women participating in in the study delivered babies between 1983 and 2018. Nine percent, or 539, of the women delivered preterm births. Phthalate metabolites were detected in more than 96 percent of urine samples.

The researchers developed statistical models to examine whether exposure to phthalates were associated with preterm birth. Higher concentrations of most phthalate metabolites examined were associated with slightly higher odds of preterm birth. Exposure to four of the 11 phthalates in pregnancy was associated with a significantly greater probability of having a preterm birth. The most consistent findings were for exposure to a phthalate that is used commonly in personal-care products such as nail polish and cosmetics.

The researchers also used computational models to simulate hypothetical interventions that could reduce phthalate exposure. They estimated that reducing the phthalate exposure by even 50 percent could reduce preterm birth by 12 percent. The potential interventions could be behavioral, such as selecting personal-care products that don’t contain phthalates (if listed on label); voluntary actions from companies to eliminate phthalates from their products; or regulatory in nature.

“Our data demonstrate that if we could reduce our exposures to phthalates, we could make considerable progress towards reducing our unacceptably high rates of preterm birth,” said Barrett.

Eating fresh, home-cooked food as often as possible, avoiding processed food that comes in plastic and selecting fragrance-free products or those labeled as “phthalate free,” are some examples of ways pregnant people can reduce their exposure to the chemicals.

The researchers are conducting additional studies to better understand the mechanisms by which exposure to phthalates can impact pregnancy and determine if there are effective ways for mothers to reduce their exposure.

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JOURNAL

JAMA Pediatrics

DOI

10.1001/jamapediatrics.2022.2252 

METHOD OF RESEARCH

Data/statistical analysis

SUBJECT OF RESEARCH

People

ARTICLE TITLE

Associations Between Prenatal Urinary Biomarkers of Phthalate Exposure and Preterm Birth

ARTICLE PUBLICATION DATE

11-Jul-2022

Our Synthetic Environment - Libcom.org

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by M Bookchin · Cited by 270 — The link between environment and illness is becoming difficult to ignore. This is not to say that every degenerative disease is environmentally induced. But it ...

101 pages