University of Houston scientists solving meteorological mysteries on Mars
University of Houston – A groundbreaking achievement by scientists at the University of Houston is changing our understanding of climate and weather on Mars and providing critical insights into Earth’s atmospheric processes as well.
The study, led by Larry Guan, a graduate student in the Department of Physics at UH’s College of Natural Sciences and Mathematics, under the guidance of his advisors, Professor Liming Li from the Department of Physics and Professor Xun Jiang from the Department of Earth and Atmospheric Sciences and several world-renowned planetary scientists, generated the first-ever meridional profile of Mars’ radiant energy budget, or REB, which represents the balance or imbalance between absorbed solar energy and emitted thermal energy across the latitudes.
On a global scale, an energy surplus leads to global warming, while a deficit results in global cooling. Furthermore, the meridional profile of Mars’ REB fundamentally influences weather and climate patterns on the red planet.
The findings are in a new paper published in AGU Advances and will be featured in AGU’s prestigious science magazine EOS.
“The work in establishing Mars’ first meridional radiant energy budget profile is noteworthy,” Guan said. “Understanding Earth’s large-scale climate and atmospheric circulation relies heavily on REB profiles, so having one for Mars allows critical climatological comparisons and lays the groundwork for Martian meteorology.”
The profile, based on long-term observations from orbiting spacecraft, offers a detailed comparison of Mars’ REB to that of Earth, uncovering striking differences in the way each planet receives and radiates energy. While Earth exhibits an energy surplus in the tropics and a deficit in the polar regions, Mars displays the opposite configuration.
“On Earth, the tropical energy surplus drives warming and upward atmospheric motion, while the polar energy deficit causes cooling and downward atmospheric motion,” Jiang explained. “These atmospheric motions significantly influence weather and climate on our home planet. However, on Mars, we observe a polar energy surplus and a tropical energy deficit.”
That surplus, Guan says, is especially pronounced in Mars’ southern hemisphere during spring, playing a critical role in driving the planet’s atmospheric circulation and triggering global dust storms, the most prominent feature of Martian weather. These massive storms, which can envelop the entire planet, significantly alter the distribution of energy, providing a dynamic element that affects Mars’ weather patterns and climate.
“The interaction between dust storms and the REB, as well as with polar ice dynamics, brings to light the complex feedback processes that likely shape Martian weather patterns and long-term climate stability,” Guan said.
Earth’s global-scale energy imbalance has been recently discovered, which significantly contributes to global warming at a magnitude comparable to that caused by increasing greenhouse gases. Mars presents a distinct environment due to its thinner atmosphere and lack of anthropogenic effects. The research team is now examining potential long-term energy imbalances on Mars and their implications for the planet’s climate evolution.
“The REB difference between the two planets is truly fascinating, so continued monitoring will deepen our understanding of Mars’ climate dynamics,” Li said. “This research not only deepens our knowledge of the Red Planet but also provides critical insights into planetary atmospheric processes.”
Also contributing to this major achievement were UH graduate students Ellen Creecy and Xinyue Wang, renowned planetary scientists Germán Martínez, Ph.D. (Houston’s Lunar and Planetary Institute), Anthony Toigo, Ph.D. (Johns Hopkins University), Mark Richardson, Ph.D. (Aeolis Research), Prof. Agustín Sánchez-Lavega (Universidad del País, Vasco, Spain) and Prof. Yeon Joo Lee (Institute for Basic Science, South Korea).
Journal Reference:
Larry Guan, Liming Li, Ellen C. Creecy, Xun Jiang, Xinyue Wang, Germán Martínez, Anthony D. Toigo, Mark I. Richardson, Agustín Sánchez-Lavega, Yeon Joo Lee, ‘Distinct Energy Budgets of Mars and Earth’, AGU Advances 5 (6) e2024AV001389 (2024). DOI: 10.1029/2024AV001389
Article Source:
Press Release/Material by University of Houston
Virginia Tech study extends chart of life by nearly 1.5 billion years
Kelly Izlar | Virginia Tech – If all the world’s a stage and all the species merely players, then their exits and entrances can be found in the rock record.
Fossilized skeletons and shells clearly show how evolution and extinction unfolded over the past half a billion years, but a new Virginia Tech analysis extends the chart of life to nearly 2 billion years ago.
The chart shows the relative ups and downs in species counts, telling scientists about the origin, diversification, and extinction of ancient life.
With this new study, the chart of life now includes life forms from the Proterozoic Eon, 2,500 million to 539 million years ago. Proterozoic life was generally smaller and squishier – like sea sponges that didn’t develop mineral skeletons – and left fewer traces to fossilize in the first place.
Virginia Tech geobiologist Shuhai Xiao and collaborators published in the journal Science a high-resolution analysis of the global diversity of Proterozoic life based on a global compilation of fossil data.
Xiao and his team looked specifically at records of ancient marine eukaryotes – organisms whose cells contain a nucleus. Early eukaryotes later evolved into the multicellular organisms credited for ushering in a whole new era for life on Earth, including animals, plants, and fungi.
“This is the most comprehensive and up-to-date analysis of this period to date,” said Xiao who recently was inducted into the National Academy of Sciences. “And more importantly, we’ve used a graphic correlation program that allowed us to achieve greater temporal resolution.”
The choreography of species offers critical insights into the parallel paths of the evolution of life and Earth.
Observed patterns and insights suggested by the analysis:
- The first eukaryotes arose no later than 1.8 billion years ago and gradually evolved to a stable level of diversity from about 1,450 million to 720 million years ago, a period aptly known as the “boring billion,” when species turnover rates were remarkably low.
- Eukaryotic species in the “boring billion” may have evolved slower and lasted longer than those came later.
- Then cataclysm: Snowball Earth, a spiral of plunging temperatures, sealed the planet in ice at least twice between 720 million and 635 million years ago. When the ice eventually thawed, evolutionary activity picked up, and things weren’t so boring anymore.
“The ice ages were a major factor that reset the evolutionary path in terms of diversity and dynamics,” Xiao said. “We see rapid turnover of eukaryotic species immediately after glaciation. That’s a major finding.”
The patterns, Xiao said, raise a lot of interesting questions, including:
- Why was eukaryotic evolution sluggish during the “boring billion”?
- What factors contributed to the increased pace of evolution after snowball ice ages?
- Was it environmental, such as climate changes and increases in atmospheric oxygen level?
- Was it an evolutionary arms race between different organisms that could drive creatures to evolve quickly?
Future scientists can use the quantified pattern to answer these questions and better understand the complex interplay of life on Earth and the Earth itself.
Study collaborators include:
- Qing Tang, first author, former graduate student and postdoctoral researcher, now at Nanjing University, as well as former graduate students Drew Muscente, now at Princeton Consultants, and Natalia Bykova, now at the University of Missouri, who worked in Xiao’s lab in the past decade
- Researchers from the University of Hong Kong; University of California, Santa Barbara; Princeton Consultants; University of Missouri; Russian Academy of Sciences; University of California, Riverside; Chinese Academy of Sciences; and Northwest University (China)
Journal Reference:
Qing Tang et al. ‘Quantifying the global biodiversity of Proterozoic eukaryotes’, Science 386, 6728, eadm9137 (2024). DOI: 10.1126/science.adm9137
Article Source:
Press Release/Material by Virginia Tech
La Brea Tar Pits researchers identify a mysterious fossil seed to reveal new chapters in LA’s climate history
Natural History Museum of Los Angeles County – La Brea Tar Pits scientists have identified a previously unknown juniper species to the La Brea Tar Pits as Juniperus scopulorum, commonly known as the Rocky Mountain juniper.
The successful identification, along with the first-ever radiocarbon dating of these fossil plants in Southern California, expands our ability to track past environmental changes and highlights the vulnerability of junipers and the environments they shape in the face of modern climate change.
Published in the journal New Phytologist, the study unlocks a key finding to understanding the megafaunal extinction at the Tar Pits and better understanding our own climate future.
The mammoths and saber-toothed cats that shape our imagination of Ice Age Los Angeles browsed, grazed, and hunted in juniper woodlands. More than just a source of food for giant herbivores, junipers were keystone trees and shrubs in the region, in turn shaping the landscape for at least 47,000 years before completely vanishing from the region in the same extinction event that erased most of the megafauna.
Researchers have long known that there are two different species of juniper found at the Tar Pits – the large-seeded J. californica (California juniper), and the small-seeded, mystery juniper. With distinct tolerances for temperature and drought, fossil junipers play a crucial role in understanding the changing climate of the last Ice Age, and how junipers can survive our climate future, but the identity of the mystery seed remained uncertain until now.
“We set out to identify this mystery juniper, and in the process, we found a number of exciting things,” says Dr. Jessie George, postdoctoral researcher at La Brea Tar Pits, and lead author on the study. “Number one, we identified this juniper as Rocky Mountain juniper, and it is one of the most extreme examples of a plant going extinct locally. It’s not present anywhere in California today.”
As part of the study, George and the other Tar Pits researchers radiocarbon dated the two species of juniper, which led to the second exciting finding: “In the process of radiocarbon dating these juniper species, we found this really interesting pattern of reciprocal presence either California juniper only or Rocky Mountain juniper only.”
Because each plant survives in specific conditions, its presence acts as a proxy for climate. George and her colleagues found that this dance between the two junipers coincided with long periods of drought and warm, dry weather that would otherwise be hidden in the fossil record.
“California juniper is a much more drought tolerant species. It withstands moisture deficit way better than Rocky Mountain juniper,” says George. “Through these back-and-forth occurrences of the two species from the Tar Pits, we have this really fascinating record of aridity and drought that was previously undetected.”
The small size of the unknown juniper seed – about as big as Lincoln’s forehead on a penny – made it a difficult subject, especially since DNA has yet to be extracted from Tar Pits fossils. Instead, George compared the structure of seeds and branchlets to other juniper species – the only way to uncover its identity. It required careful comparison using advanced microscopy, image analysis, and species distribution modeling (SDM) until the team reached a definitive answer.
While climate definitely played an important role in their local extinction, the team thinks that the abrupt disappearance of Ice Age megafauna and fires started by humans may have also contributed, much like in the case of those iconic giant mammals. In a hotter, drier climate, even plants well-adapted to drought couldn’t survive the extra stress of human fires.
This is especially true for plants that are not adapted to wildfire – unlike many other conifer species, juniper has little tolerance for surviving or re-growing following fires. The finding highlights the threat junipers continue to face from human-caused climate change and could inform conservation efforts going forward.
“We’re seeing events of really dramatic decline of these trees in the southwest today because of warming temperatures and increased wildfire caused by modern climate change. So a direct record of how this might have occurred in the past, what factors were at play, and where those boundaries occurred is incredibly important,” says George. “It gives us a better framework to understand a baseline of climate and environment to contextualize changes in other plant life and the fauna that we see during these periods of significant change in the past. As our ability to precisely date fossils improves, better and more detailed information is revealed from ancient life at La Brea.”
Journal Reference:
Jessie George, Monica Dimson, Regan E. Dunn, Emily L. Lindsey, Aisling B. Farrell, Brenda Paola Aguilar, Glen M. MacDonald, ‘Identification of fossil juniper seeds from Rancho La Brea (California, USA): drought and extirpation in the Late Pleistocene’, New Phytologist (2024). DOI: 10.1111/nph.20324
Article Source:
Press Release/Material by Natural History Museum of Los Angeles County, USA
Genes linked to deadly parasites’ spread beyond Africa identified
University of Edinburgh – The findings reveal that climate change and measures to control populations of tsetse flies, which carry the disease, may drive molecular changes in the organisms that cause sleeping sickness – which can be fatal if left untreated.
The parasites – known as African trypanosomes – are normally transmitted by tsetse flies in sub-Saharan Africa. However, they have evolved to enable them to cause infection without tsetse flies, researchers say.
New strains that directly infect animals have been detected in Asia, South America and southern Europe. There is a risk that the same could happen in forms that affect people, the team says.
Until now, the molecular changes that give rise to these new, more virulent forms of the parasites were unknown.
A team led by scientists at the University of Edinburgh has revealed that changes to key genes have simplified the organism’s life cycle, enabling it to spread beyond its normal geographical range.
Researchers analysed the genetic make-up of more than 80 samples of trypanosomes collected from people, tsetse flies, cows and other animals. The information was used to construct a family tree of different parasite strains.
The team then used a gene-editing tool – called CRISPR-Cas9 – to test whether different molecular changes are involved in the parasite’s evolution to spread without tsetse flies. This revealed multiple mutations in genes that play an important role in their life cycle.
Knowing which genes and specific mutations are involved could be key in identifying and combatting emerging virulent strains of the parasites, the team says.
Professor Keith Matthews, of the University of Edinburgh’s School of Biological Sciences, who co-led the study, said: “Trypanosomes have found ways to expand their geographic range by excluding the tsetse fly from their life cycle. The molecular changes they exhibit can allow us to detect the emergence of these virulent parasites that threaten both cattle and, potentially, humans.”
The study, published in the journal Nature Communications, was supported by the Wellcome Trust, Medical Research Council, Bill & Melinda Gates Foundation and the Flemish Government. It also involved researchers from the University of York, KU Leuven, Institute of Tropical Medicine, Antwerp, and the French Agency for Food, Environmental and Occupational Health & Safety.
Dr Guy Oldrieve, also of the University of Edinburgh’s School of Biological Sciences, the other study co-author, said: “We plan to continue this research and develop a portable diagnostic tool to facilitate detection of future outbreaks in real-time.”
Journal Reference:
Oldrieve, G.R., Venter, F., Cayla, M., Matthews, K.R. et al. ‘Mechanisms of life cycle simplification in African trypanosomes’, Nature Communications 15, 10485 (2024). DOI: 10.1038/s41467-024-54555-w
Article Source:
Press Release/Material by University of Edinburgh
Pine-oak forests and frequent fires have been a predominant feature of Albany Pine Bush, New York, for the last 11,000 years
PLOS ONE – Two radiocarbon-dated pollen and charcoal records from cores collected at Stump Pond and a wetland in suburban Albany County, New York, provide new insights into the environmental history of a unique inland pine barrens that is currently surrounded and threatened by urban development: the Albany Pine Bush (APB).
The Stump Pond core shows that the pond formed roughly 13,000 years ago with the recession of glacial Lake Albany.
From ca. 13,000 to 11,000 years ago spruce (Picea) and other boreal forest taxa were more common in the region than they are today, but both cores show that pine-oak (Pinus-Quercus) assemblages similar to those of today’s APB have been predominant components of the local forests for the last ca. 11,000 years.
Abundant charcoal in both cores demonstrates that fire activity was a frequent occurrence in the APB throughout its history, particularly for the last ca. 6400 years. Water tables rose in response to increasingly humid hydroclimates, leading to the establishment of the wetland site ca.
6400 years ago and a greater abundance of ferns and mosses there during the last millennium. More recently, expanding urbanization and its associated impacts demonstrate that human activity has become the primary driver of change in the APB ecosystem.
Journal Reference:
Tremblay M, Stager JC, St-Jacques J-M, Murphy S, Peros M, Carl BS, ‘A 13,000-year history of vegetation and fire in a rare inland pine barrens: The Albany Pine Bush (Albany County, New York, USA)’, PLoS ONE 19(12): e0314101 (2024). DOI: 10.1371/journal.pone.0314101
Article Source:
Press Release/Material by PLOS
Featured image credit: Gerd Altmann | Pixabay
