Paleontologists identify two new species of sabertooth cat

 Sabertooth cats make up a diverse group of long-toothed predators that roamed Africa around 6-7 million years ago, around the time that hominins -- the group that includes modern humans -- began to evolve. By examining one of the largest global Pliocene collections of fossils in Langebaanweg, north of Cape Town in South Africa, researchers present two new sabertooth species and the first family tree of the region's ancient sabertooths on July 20 in the journal iScience. Their results suggestthat the distribution of sabertooths throughout ancient Africa might have been different than previously assumed, and the study provides important information about Africa's paleoenvironment.

"The known material of sabertooths from Langebaanweg was relatively poor, and the importance of these sabertoothed cats has not been properly recognized," says senior author Alberto Valenciano, a paleontologist at Complutense University. "Our phylogenetic analysis is the first one to take Langebaanweg species into consideration."

The study described a total of four species. Two of these species, Dinofelis werdelini and Lokotunjailurus chimsamyae, were previously unknown. Dinofelis sabertooths are globally distributed, and their fossils have been found in Africa, China, Europe, and North America. The researchers were expecting to identify a new Dinofelis species from Langebaanweg based on prior research. However, Lokotunjailurus has only ever been identified in Kenya and Chad before this analysis. This suggests that they may have been distributed all throughout Africa between 5-7 million years ago.

Valenciano was a postdoctoral fellow at the Iziko Museums of South Africa, which houses all the sabertooth fossils that were analyzed in this study. A team of colleagues from China, South Africa, and Spain put the final project together. To construct a family tree, the researchers classified the physical traits of each sabertooth species -- such as presence or absence of teeth, jaw and skull shape, and tooth structure -- and coded this information into a matrix that could determine how closely related each sabertooth was to its evolutionary cousins.

The resulting population composition of Langebaanweg sabertooths (Machairodontini, Metailurini, and Feline) reflects the increasing global temperatures and environmental changes of the Pliocene epoch. For instance, the presence of Machairodontini cats, which are larger in size and more adapted to running at high speeds, suggests that there were open grassland environments at Langebaanweg. However, the presence of the Metailurini cats suggests that there were also more covered environments, such as forests. While the fact that researchers found both Metailurine and Machairodonti species suggests that Langebaanweg contained a mixture of forest and grassland 5.2 million years ago, the high proportion of Machairodonti species compared with other fossil localities from Eurasia and Africa confirm that southern Africa was transitioning toward more open grasslands during this period.

"The continuous aridification throughout the Mio-Pliocene, with the spread of open environments, could be an important trigger on the bipedalism of hominids," the authors write. "The sabertooth guild in Langebaanweg and its environmental and paleobiogeographic implications provide background for future discussion on hominid origination and evolution."

Interestingly, the researchers also note that the composition of sabertooths in Langebaanweg closely mirrors that of Yuanmou, China. Yuanmou's Longchuansmilus sabertooths might even have a close evolutionary relationship with Africa's Lokotunjailurus species.

"This suggests that the ancient environment of the two regions was similar or that there was a potential migration route between the Langebaanweg and Yuanmou," says first author Qigao Jiangzuo, a paleontologist at Peking University.

More fossil evidence could help paleontologists understand exactly how these two sites are related. "The two new sabertooths are only an example of the numerous unpublished fossils from Langebaanweg housed at Iziko in the Cenozoic Collections," says Romala Govender, a curator and paleontologist at the Iziko Museums in South Africa. "This brings to the fore the need for new and detailed studies of Langebaanweg fauna."

Using our oceans to fight climate change

 The ocean isn't just impacted by climate change -- it may also be part of the solution to reversing it.

Direct ocean carbon capture (DOC) is an emerging form of negative emissions technology that has advantages over its on-land counterpart, direct air capture, because of its ability to avoid land use. DOC can also conveniently be paired with offshore wind and offshore carbon dioxide storage.

Katherine Hornbostel, an assistant professor of mechanical engineering and materials science at the University of Pittsburgh Swanson School of Engineering, is well-versed in the field of carbon capture technologies. She has been actively collaborating with Assistant Professor Tagbo Niepa from Pitt's Department of Chemical and Petroleum Engineering to develop innovative ocean carbon capture solutions.

The team published two sister papers, "Demonstration of direct ocean carbon capture using encapsulated solvents" and "Demonstration of direct ocean carbon capture using hollow fiber membrane contactors," in the Chemical Engineering Journal. These two papers demonstrate experimentally and computationally how two types of membrane contactors -- encapsulated solvents and hollow fiber membrane contactors -- can remove carbon dioxide from the ocean.

"Membrane contactors are just what they sound like," Hornbostel said. "They're membranes that bring two fluids into contact with each other. In this case, we're bringing together ocean water on one side and a solvent on the other."

The team tested two types of membrane contactors: hollow fiber and encapsulated solvents. The biggest difference between the two technologies is their shape. While hollow fiber membrane contactors look like straws, encapsulated solvents look like caviar. Otherwise, they work exactly the same.

"The idea with both is to get a really high surface area of contact between seawater and solvent," Hornbostel explained. "The more surface area you have, the better the carbon dioxide removal rate."

Swinging the Seawater

Carbon dioxide will want to travel across the membrane towards the solvent, made from a sodium solution that reacts with carbon dioxide. When seawater comes into contact with the solvent, the carbon dioxide will react and separate from the seawater. The solution then has to be re-circulated to make the process more cost effective -- something the team is still working to improve.

"Theoretically, we could significantly lower the price if we could swing the pH of the seawater side," Hornbostel said. "Carbon dioxide is not typically available in seawater at its baseline level of pH, so you have to swing the pH lower in the seawater to make it more acidic and then more carbon dioxide bubbles off."

Hornbostel's team is currently pursuing methods for swinging seawater pH with membrane surface treatments and investigating coupling direct ocean capture with desalination to lower system costs.

Risk of fatal heart attack may double in heat wave and high fine particulate pollution days

 The combination of soaring heat and smothering fine particulate pollution may double the risk of heart attack death, according to a new study of more than 202,000 heart attack deaths in China. The study published today in the American Heart Association's flagship journal Circulation.

"Extreme temperature events are becoming more frequent, longer and more intense, and their adverse health effects have drawn growing concern. Another environmental issue worldwide is the presence of fine particulate matter in the air, which may interact synergistically with extreme temperatures to adversely affect cardiovascular health," said senior author Yuewei Liu, M.D., Ph.D., an associate professor of epidemiology in the School of Public Health at Sun Yat-sen University in Guangzhou, China. "However, it remains unknown if and how co-exposure to extreme temperatures and fine particulate pollution might interact to trigger a greater risk of death from heart attack, which is an acute response potentially brought on by an acute scenario and a great public health challenge due to its substantial disease burden worldwide."

To examine the impact of extreme temperatures with and without high levels of fine particulate pollution, the researchers analyzed 202,678 heart attack deaths between 2015-2020 that occurred in Jiangsu province, a region with four distinct seasons and a wide range of temperatures and fine particulate pollution levels. The deaths were among older adults with an average age of 77.6 years; 52% were older than age 80; and 52% were male. Particulate exposure on the day of each death and one day before death were included in the analysis.

Extreme temperatures were gauged according to the daily heat index (also referred to as apparent temperature) for an area, which captures the combined effect of both heat and humidity. Both the length and extremeness of heat waves and cold snaps were evaluated. Heart attack deaths, or case days, during these periods were compared with control days on the same day of the week in the same month -- meaning that if a death occurred on a Wednesday, all other Wednesdays in the same month would be considered control days. Particulate levels were considered high on any day with an average level of fine particulate matter above 37.5 micrograms per cubic meter.

"Our findings provide evidence that reducing exposure to both extreme temperatures and fine particulate pollution may be useful to prevent premature deaths from heart attack, especially for women and older adults," Liu said.

Compared with control days, the risk of a fatal heart attack was observed at the following levels:

• 18% higher during 2-day heat waves with heat indexes at or above the 90th percentile (ranging from 82.6 to 97.9 degrees Fahrenheit), increasing with temperature and duration, and was 74% higher during 4-day heat waves with heat indexes at or above the 97.5th percentile (ranging from 94.8 to 109.4 degrees Fahrenheit). For context, 6,417 (3.2%) of the 202,678 observed deaths from heart attack happened during heat waves with heat indexes at or above the 95th percentile (ranging from 91.2 to 104.7 degrees Fahrenheit) for three or more days.
• 4% higher during 2-day cold snaps with temperatures at or below the 10th percentile (ranging from 33.3 to 40.5 degrees Fahrenheit), increasing with lower temperatures and duration, and was 12% higher during 3-day cold snaps with temperatures at or below the 2.5th percentile (ranging from 27.0 to 37.2 degrees Fahrenheit). For context, 6,331 (3.1%) of the 202,678 observed deaths from heart attack happened during cold spells with temperatures at or below the 5th percentile (ranging from 30.0 to 38.5 degrees Fahrenheit) for 3 or more days.
• Twice as high during 4-day heat waves that had fine particulate pollution above 37.5 micrograms per cubic meter. Days with high levels of fine particulate pollution during cold snaps did not have an equivalent increase in the risk of heart attack death.
• Generally higher among women than men during heat waves.
• Higher among people ages 80 and older than in younger adults during heat waves, cold snaps or days with high levels of fine particulate pollution.
• The mean age of all individuals who died from a heart attack in Jiangsu from 2015-2020, including during non-extreme temperature events, was 77.6 years old; 52.1% of these individuals were over 80 years old.

The researchers estimated that up to 2.8% of heart attack deaths may be attributed to the combination of extreme temperatures and high levels of fine particulate pollution (> 37.5 micrograms per cubic meter), according to WHO targets.

"Strategies for individuals to avoid negative health effects from extreme temperatures include following weather forecasts, staying inside when temperatures are extreme, using fans and air conditioners during hot weather, dressing appropriately for the weather, proper hydration and installing window blinds to reduce indoor temperatures," said Liu. "Using an air purifier in the house, wearing a mask outdoors, staying clear of busy highways when walking and choosing less-strenuous outdoor activities may also help to reduce exposure to air pollution on days with high levels of fine particulate pollution. To improve public health, it is important to take fine particulate pollution into consideration when providing extreme temperature warnings to the public."

In a 2020 scientific statement and a 2020 policy statement, the American Heart Association details the latest science about air pollution exposure and the individual, industrial and policy measures to reduce the negative impact of poor air quality on cardiovascular health. Reducing exposure to air pollution and reversing the negative impact of poor air quality on cardiovascular health, including heart disease and stroke, is essential to reducing health inequities in Black and Hispanic communities, those that have been historically marginalized and under-resourced, and communities that have the highest levels of exposure to air pollution.

The investigators recommended additional research about the possible interactive effects of extreme weather events and fine particulate pollution on heart attack deaths in areas with different temperature and pollution ranges to confirm their findings. The study did not include adjustments for any adaptive behaviors taken by individuals, such as using air conditioning and staying indoors, when temperatures are extreme or pollution levels are high, which could cause misclassification of individuals' exposure to weather and alter their risk patterns. These results also may not be generalizable to other regions in China or other countries due to potential variations of adaption capacity and temperature distribution.

Background:

• Fine particulates are less than 2.5 microns in size and may be inhaled deep into the lungs, where they can irritate the lungs and blood vessels around the heart. Most are associated with fuel combustion, such as particles from car exhaust, factory emissions or wildfires.
• Previous research has confirmed that exposure to particulate matter including fine particulates is linked to heart disease, stroke and other health issues.
• For context, the World Health Organization's target for average annual exposure to fine particulate pollution level is no more than 5 micrograms per cubic meter and no more than 15 micrograms per cubic meter for more than 3-4 days per year.
• In this study, heat waves were defined as periods at or above the 90th, 92.5th, 95th and 97.5th percentiles of daily heat indexes (ranging from 82.6 to 109.4 degrees Fahrenheit across Jiangsu province, China) for at least 2, 3 or 4 consecutive days.
• Cold spells were defined as periods at or below the 10th, 7.5th, 5th, 2.5th percentiles of daily heat indexes (ranging from 27 to 40.5 degrees Fahrenheit) for at least 2, 3 or 4 consecutive days.
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What can central Utah's earthquake 'swarms' reveal about the West's seismicity?

 Most of the earthquakes rumbling under the West's Great Basin come in surges, clustered together in time and place. Scientists call these seismic groups "swarms," which are a distinct category from the numerous aftershocks following a big shake, such as the 5.7 magnitude Magna quake of 2020 on the Wasatch Fault.

Rather than getting spread out evenly over time, many of these small, often imperceptible quakes strike a region in a short period of time, say a few days or weeks.

Central Utah has been the stage for dozens of earthquake swarms that have been recorded over the past 40 years by an ever-expanding network of seismic arrays managed by the University of Utah.

Now U seismologists are analyzing decades of seismic data in hopes of discerning the significance of these swarms in a geologically complex region known as a geothermal hotspot and for recent -- geologically speaking -- volcanism.

"In central Utah, seismic swarms are much more common than any other type of sequence. We looked into all types of sequences, but 80% of the sequences are swarms. That's remarkable," said Gesa Petersen, a post-doctoral research fellow. "We also saw that these are very heterogeneous. So one location in central Utah can have a very, very different behavior than other locations just 30, 40, 50 kilometers away."

With U. geology professor Kristine Pankow, Petersen publish the latest findings July 13 in the journal Geochemistry, Geophysics, Geosystems. Funding came from the state of Utah and the $220 million Department of Energy grant supporting the U's geothermal research station known as Utah FORGE.

A geothermal hot spot

Located outside Milford, FORGE is within the research area that spans Beaver, Iron, Sevier and Paiute counties. The research area is home to three geothermal power-generating plants and includes the towns of Circleville, Beaver and Richfield.The researchers suspect the earthquakes are triggered by hot water, powered by geothermal activity, coursing through fissures in Earth's crust.

During the past 40 years, the U of U Seismograph Stations detected earthquake sequences featuring earthquakes of magnitude 1.5 or greater. But in further examining the data, Peterson and Pankow were able to identify hundreds of additional smaller earthquakes, as small as magnitude 0.5 recorded in 50 distinct sequences.

They concluded 40 qualified as swarms. Much can be learned from these smaller quakes, but they are hard to study, according to Pankow, who is the Seismograph Stations associate director.

(BRT) and Cove Fort (CVT) Transverse Zones (P. D. Rowley, 1998), thin black lines indicate Quaternary faults. MP: Markagunt Plateau Volcanic Field. The larger map (c) shows seismicity in the study area since 1981, ML ? 2.5 (UUSS).

"We're all worried about the Wasatch Front, but the other thing to know is we have earthquakes all over Utah," said Pankow. "We recorded a certain level, but in some of these places there's probably earthquakes happening all the time that we just don't see. That's something that's really important to get an understanding of."

Thousands of earthquakes

All told the research analyzed 2,300 earthquakes, most of which were between magnitude 1 and 3. The largest was a magnitude 5.1 that hit east of Richfield in 1989. That one was not part of a swarm, but rather was a mainshock followed by numerous aftershocks. The full catalog for the study area contains 20,000 events between 1981 and 2023, according to Petersen.

"However, we cannot exactly say how many of them are part of a sequence because we limit the study for sequences that have at least 20 earthquakes within 10 days. We do not look into smaller sequences because we need some minimum to look at statistical parameters and to compare characteristic patterns of the sequences," she said. "However, in the 1980s and 1990s, the seismic network of Utah was not as dense as today. There were significantly less stations. Therefore we can only study larger sequences with larger magnitudes from these times. There were likely many more swarms or seismic sequences."

The study greatly expanded on another recent study that focused exclusively on a swarm of hundreds of small quakes around Milford in the spring of 2021. That area had not experienced much earthquake activity during the entire 40-year window of seismograph data. Meanwhile, earthquakes have been happening as frequently as every few months in the nearby Mineral Mountains to the west during this same time period, Petersen said.

"So it's a very heterogeneous system there," she said. "You have a bunch of earthquakes in the same place and you can start learning about the structures that are activated in the place. If you have like only a single earthquake, you can't learn that much then."

The Mineral Mountains swarms were first detected a few years ago when new seismometers were installed for the FORGE geothermal research project.

"Before that we didn't have the resolution, but now we can see there are events always coming, and it's rapid," Petersen said. "Within a couple of hours, you suddenly have 30, 40, 50 events and then it's pausing again. You have this repeatedly, you have lots of activity. You can't really feel it. It's too small for that, but we can see it on the seismometers."

Climate scientist finds new way to measure the Earth's ability to offset carbon emissions

 A Chapman University scientist and his colleagues have determined how the Earth responds as it heats up due to climate change.

The scientists say a warming world calls for a new approach in detecting how much carbon dioxide comes out of ecosystems when the temperature changes -- which tells us how well plants and soil can alleviate damage by removing carbon pollution from the atmosphere. The study is the first to find the temperature-carbon dioxide release relationship at the landscape level.

Their findings are published in the academic peer-reviewed journal Nature Ecology & Evolution.

Plants that currently take up a quarter to a third of humanity's carbon emissions might not be able to maintain the rate of carbon dioxide removal, says Joshua Fisher, a climate scientist and associate professor of environmental science and policy at Chapman University's Schmid College of Science and Technology.

"A big unknown in the future of the Earth is how ecosystems will respond to increasing temperature," says Fisher. "Our findings give us insight into the fate of the planet, and how we can measure those changes at large scales."

Recent developments, including those by Fisher, have led to the use of satellites to monitor global photosynthetic activity and measure the concentrations of gas in plants and ground soil; but, similar tools have been unable to track respiration, or the "breathing" out of carbon dioxide, across biomes and continents. Respiration continues to be indirectly estimated as the difference between photosynthesis and the overall change in carbon dioxide, and "the spot measurements are not representative of the larger landscape," Fisher says.

So, he and other scientists took to the trees -- well, monitoring stations among the trees. New carbon dioxide measurements were taken by a network of dozens of monitoring stations on towers across North America. The results gave great insight into future measurements over larger swaths of land.

When they compared landscape measurements from the tower stations to the spot measurements done on the ground, they found the ground measurements show an overly sensitive relationship between carbon dioxide and temperature that does not exist when looking at the larger landscape. "Ground measurements said there's a lot of CO2 emission for small changes in temperature; but the landscape measurements said there's not a lot of CO2 emission for small changes in temperature," Fisher says.

The team later used the findings to update mathematical models used to predict the relationships, and found that when they were improved with the findings, they performed better.

"This is a very clever study that harnessed a myriad of measurements, models, and understanding of how they synergize together," says Fisher. "Our results continue to march us forward in deeper understanding of the Earth and what it may mean if we continue to change its climate."

The study was funded by the NASA Terrestrial Ecology Interdisciplinary Science and Carbon Monitoring System, the Carnegie Institution for Science's endowment, Singapore's Ministry of Education, the RUBISCO SFA, which is sponsored by the Regional and Global Model Analysis Program in the Climate and Environmental Sciences Division of the Office of Biological and Environmental Research in the U.S. Department of Energy Office of Science, and NASA.

Other members of the research team include lead author Wu Sun and Anna Michalak of Carnegie Institution for Science; Xiangzhong Luo, Yao Zhang, and Trevor Keenan of University of California Berkeley and Lawrence Berkeley National Laboratory; Yuanyuan Fang of the Bay Area Air Quality Management District; and Yoichi P. Shiga of the Universities Space Research Association.