Researchers make breakthrough in understanding species abundance

When it comes to predicting the abundance of a species, body size appears to be a fundamental and repeatable predictor, with smaller organisms occurring in greater numbers than larger ones. The caveat, known as Bermann's Rule, is that in polar regions larger bodied organisms predominate. Other factors that influence species abundance include light availability, food availability, competition and predation.

New findings by a team of researchers in biological sciences at the U of A have now added a genetic component to our understanding of species abundance.

Genome size, the total amount of DNA contained within one copy of a single complete genome, can also be a strong predictor of species abundance. The paper examined diatoms, which are unicellular algae that play an important role in freshwater and marine food webs. They create long-chain fatty acids, like fish oil and other lipids, that serve as energy. The energy molecules that diatoms produce go up the food web from zooplankton to aquatic insects to fish to humans.

Diatoms also play a critical role in photosynthesis, the process by which carbon dioxide is converted to oxygen. It's estimated that 20-25 percent of Earth's oxygen comes from diatoms -- more than rainforests and land plants.

The key finding was that temperature and genome size, not body size, had the greatest influence on the maximum population growth rate of the diatoms. Yet body size still mattered in colder latitudes, conserving Bermann's Rule.

The paper, "Diatom abundance in the polar oceans is predicted by genome size," was published in PLoS Biology by a trio of authors from the Department of Biological Sciences: Wade Roberts, a postdoctoral researcher in the Alverson Lab; Adam Siepielski, an associate professor; and Andrew Alverson, professor and director of the Alverson Lab.

Roberts noted that the genome size of a diatom is critical to cell function and its ability to adapt to a changing environment.

"In phytoplankton, cell size is highly correlated to genome size," Roberts explained. "We've known that for a while. But we weren't sure if cell size was driving genome size or vice versa. We were able to directly test this through a path analysis to determine the directionality. We found that an increase in genome size led to increased cell size. So, we confirmed that size of the genome is driving cell size."

The genome size of diatoms can vary by 50-fold between species, but most of the difference in genetic material is made up of repeated DNA. DNA codes for the proteins that are the building blocks of life, but it's unclear how this repetitive DNA is utilized by the cell. It's estimated that only about 2 percent of the human genome codes for genes.

Overall, the paper's results advance understanding of species abundance by showing that a single emergent trait fundamental to all life, the size of the genome, can predict species abundance at a global scale.

"Larger organisms are more abundant in polar regions," Roberts said. "That's true of mammals and other multi-cellular organisms. But we didn't know if that was true of phytoplankton. Now we can make predictions about community composition based off temperature. This will help us predict whether larger diatoms will be able to persist in warming waters."

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Enormous ice loss from Greenland glacier

Ground-based measuring devices and aircraft radar operated in the far northeast of Greenland show how much ice the 79° N-Glacier is losing. According to measurements conducted by the Alfred Wegener Institute, the thickness of the glacier has decreased by more than 160 metres since 1998. Warm ocean water flowing under the glacier tongue is melting the ice from below. High air temperatures cause lakes to form on the surface, whose water flows through huge channels in the ice into the ocean. One channel reached a height of 500 metres, while the ice above was only 190 metres thick, as a research team has now reported in the scientific journal The Cryosphere.

A rustic camp in northeast Greenland was one of the bases for deploying autonomous measuring devices with modern radar technology by helicopter in a part of the 79° N-Glacier that is difficult to access.

Measurement flights with the polar aircraft of the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI) and satellite data were also incorporated into a scientific study that has now been published in the scientific journal The Cryosphere. This study examines how global warming affects the stability of a floating ice tongue.

This is of great importance for the remaining ice shelves in Greenland as well as those in Antarctica, as instability of the ice shelf usually results in an acceleration of the ice flow, which would lead to a greater sea level rise.

"Since 2016, we have been using autonomous instruments to carry out radar measurements on the 79° N-Glacier, from which we can determine melt and thinning rates," says AWI glaciologist Dr Ole Zeising, the first author of the publication.

"In addition, we used aircraft radar data from 1998, 2018 and 2021 showing changes in ice thickness. We were able to measure that the 79° N-Glacier has changed significantly in recent decades under the influence of global warming."

The study shows how the combination of a warm ocean inflow and a warming atmosphere affects the floating ice tongue of the 79° N-Glacier in northeast Greenland.

Only recently, an AWI oceanography team published a modelling study on this subject.

The unique data set of observations now presented shows that extremely high melt rates occur over a large area near the transition to the ice sheet.

In addition, large channels form on the underside of the ice from the land side, probably because the water from huge lakes drains through the glacier ice.

Both processes have led to a strong thinning of the glacier in recent decades.

Due to extreme melt rates, the ice of the floating glacier tongue has become 32 % thinner since 1998, especially from the grounding line where the ice comes into contact with the ocean.

In addition, a 500-metre-high channel has formed on the underside of the ice, which spreads towards the inland.

The researchers attribute these changes to warm ocean currents in the cavity below the floating tongue and to the runoff of surface meltwater as a result of atmospheric warming.

A surprising finding was that melt rates have decreased since 2018.

A possible cause for this is a colder ocean inflow. "The fact that this system reacts on such short time scales is astonishing for systems that are actually inert such as glaciers," says Prof Dr Angelika Humbert, who is also involved in the study.

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A new perspective on the temperature inside tropical forests

New worldwide maps of temperatures inside tropical forests show that global warming affect different way in different parts of the forests. Undergrowth level temperature of the tropical forests can be even 4 degrees less than average temperature of the area.

Tropical forests host up to half of the planet's biodiversity but up to now, ecological studies over tropical forests often relied on large scale datasets depicting open-air temperatures -- that is, the temperature outside the forests, which can be several degrees different from the temperatures inside the forest.

This limitation imposed a large barrier in our understanding on how species will respond to climate change.

The research coordinated at the University of Helsinki and the Finnish Meteorological Institute by associate professor Eduardo Maeda, has now achieved a major step to overcome this limitation.

The results have been published in the scientific journal Nature communication.

Hotspots of microclimate refugia

Temperature is a fundamental factor defining the survival, growth, and reproduction rate of species living inside tropical forests.

New study provides maps of temperature inside forests that can be used by ecologists to massively improve the reliability of species distribution models.

"The maps will help to predict with higher confidence how species will respond to climate change, such as to where species are more likely to migrate," says Maeda.

Furthermore, we are able to identify hotspots of microclimate refugia (i.e., areas that can maintain stable and cool microclimates). These areas are likely to be more and more important in a warming future -- with highly detailed maps provided by this study, we can now indicate to policy makers where these areas are, so they can be more efficiently preserved.

Building on an extensive international collaboration effort, the researchers compiled data from hundreds of temperature sensors installed inside tropical forests across the world.

The study also used satellite data that provided information on different characteristics of the forests, such as the height of the trees and the leaf density.

All this information were combined in a machine learning algorithm that was able to estimate temperatures inside tropical forests throughout the entire planet.

The result of this study demonstrates an amazing variability in the temperatures experienced inside forests, which were not visible from other available datasets.

For example, the differences between temperatures inside and outside forests are larger in regions with a distinct dry season (e.g., in southern Amazon forest). Areas with lower rainfall are usually associated with higher temperatures, but this study demonstrate that the deep roots of tropical trees can still access water reserves, thus maintaining their 'airconditioning' function in the ecosystem.

"We already knew that temperatures inside forest differ substantially from those outside forests. Our study shows that those differences are evident not only in terms of magnitude (ie., the absolute difference between temperature inside and outside forest) but also in terms of spatial and temporal heterogeneity," says Maeda.

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Arctic cold snap transforms into a blessing

A recent cold spell plunged the nation of Korea into a deep freeze, resulting in the closure of 247 national parks, the cancellation of 14 domestic flights, and the scrapping of 107 cruise ship voyages. While the cold snap brought relief by significantly reducing the prevalence of particulate matter obscuring our surroundings, a recent study indicates that, besides diminishing particulate matter, it is significantly contributing to the heightened uptake of carbon dioxide by the East Sea.

According to research conducted by a team of researchers including Professor Kitack Lee from the Division of Environmental Science & Engineering at Pohang University of Science and Technology (POSTECH), and Professor Tongsup Lee and So-Yun Kim from the Department of Oceanography at Pusan National University, the cold atmosphere in the Arctic is influencing the absorption of carbon dioxide by the East Sea.

The research findings were published in Geophysical Research Letters, an international journal by the American Geophysical Union (AGU).

The research team investigated the correlation between the East Sea's surface-deep circulation and its carbon dioxide absorption capacity, drawing insights from observations in 1992, 1999, 2007, and 2019.

During the initial period (1992-1999), the ocean absorbed 20 million tons of carbon dioxide annually.

In the subsequent period (1999-2007), this amount decreased to under 10 million tons per year.

However, in the final period (2007-2019), the carbon dioxide uptake surged to 30 million tons per year.

The team observed that the internal circulation along the East Coast within the East Sea was influenced by the Arctic cold wave.

Cold air from the Arctic infiltrates the East Sea, causing the surface water, laden with carbon dioxide, to become denser.

This process induces vertical ventilation as the water descends into the middle and deep ocean layers.

Consequently, the intensified descent of cold air from the Arctic strengthens the internal circulation, leading to a heightened uptake of carbon dioxide in the East Sea.

Professor Kitack Lee who led the research remarked, " The oceans represent an immense reservoir of carbon dioxide and offer a secure and sustainable avenue for mitigating atmospheric carbon dioxide levels." He further stated, "It is crucial to anticipate the global ocean's capacity for carbon removal as we navigate future climate changes and identify suitable methods to leverage this potential."

In a related development, the team's earlier research uncovered the mechanism through which the ocean absorbs carbon dioxide.

Approximately half of the carbon dioxide generated by human activities remains in the atmosphere with the other half entering marine and terrestrial ecosystems.

With a carbon content 400,000 times greater than that of the atmosphere, the oceans present vast and promising potential for storing carbon dioxide.

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Temperature variability reduces nesting success

Many songbirds are nesting earlier in spring because of warmer temperatures brought about by climate change. But the shift brings another danger that is especially deadly for nestlings: greater exposure to temperature variability in the form of cold snaps and heat waves. Such extremes result in more nest failures. These findings come from a Cornell Lab of Ornithology study just published in the journal Nature Communications.

"When we talk about temperature changes, the focus is mostly on averages," said co-lead author Conor Taff, a researcher in Cornell University's Ecology and Evolutionary Biology Department. "But all creatures, including humans, interact with weather conditions right in the moment, not with long-term averages. Even a one or two-day period when it's really cold or really hot can be incredibly challenging even if the average temperature hasn't changed. Changing temperature averages and temperature variability are two different components of climate change."

To understand how temperature variability might affect nesting success, the researchers analyzed 300,000 breeding bird records submitted to the Cornell Lab's NestWatch project between 1995 and 2020. They pinpointed the coldest three-day day period and the hottest three-day period for each one of the nests and then looked at whether those values predicted lower nesting success. Success was measured by how many nestlings survived to fledge.

"We found that 16 of the 24 species we studied had reduced reproductive success when a cold snap occurred during the incubation or nestling stages," Taff said. "Eleven of 24 had reduced success when a heat wave occurred during the breeding season. Aerial insectivores were the most sensitive to temperature extremes, especially cold."

The vast majority of birds feed insects to their young, regardless of their final diet, and cold snaps reduce insect availability. If these episodes occur when nestlings are most vulnerable, they can trigger a mass die-off. During a cold snap, adult birds may move away to find survivable conditions which leaves eggs and nestlings exposed to cold and lack of food.

"It's the nestlings that really get hit hard because they can't regulate their own body temperature yet," said co-author Ryan Shipley, a Cornell University Ph.D. student at the time of the research. "Nestlings also grow at an exponential rate during the first week or two of life and if insect activity drops because of a cold snap, the young birds likely won't survive."

Taff and Shipley also examined 100 years of weather data to see if there have been changes in the timing of cold snaps and heat waves during the March through August breeding season in the United States and Canada. Although they found no clear pattern in the timing of temperature extremes, they do note that it's getting warmer everywhere.

"Even if nestlings somehow manage to survive a cold snap or heat wave, there may still be long-term consequences affecting the overall health of the birds," notes Shipley. "We're only looking at a brief snapshot during early life and cannot measure long-term health in an unbanded wild population."

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'Biodiversity time machine' provides insights into a century of loss

Scientists have run the first proof of concept of their DNA 'time machine' to shed light on a century of environmental change in a freshwater lake -- including warming temperatures and pollution, leading to the potentially irreversible loss of biodiversity.

Their approach, which uses AI applied to DNA-based biodiversity, climate variables and pollution, could help regulators to protect the planet's existing biodiversity levels, or even improve them.

Researchers from the University of Birmingham, in collaboration with Goethe University in Frankfurt, used sediment from the bottom of a lake in Denmark to reconstruct a 100-year-old library of biodiversity, chemical pollution, and climate change levels. This lake has a history of well-documented shifts in water quality, making it a perfect natural experiment for testing the biodiversity time machine.

Publishing their findings today (7 Nov) in eLife, the experts reveal that the sediment holds a continuous record of biological and environmental signals that have changed over time -- from (semi)pristine environments at the start of the industrial revolution to the present.

The team used environmental DNA -- genetic material left behind by plants, animals, and bacteria -- to build a picture of the entire freshwater community. Assisted by AI, they analysed the information, in conjunction with climate and pollution data, to identify what could explain the historic loss of species that lived in the lake.

Principal investigator Luisa Orsini, Professor of Evolutionary Systems Biology and Environmental Omics at the University of Birmingham and Fellow of the Alan Turing Institute, explained: "We took a sediment core from the bottom of the lake and used biological data within that sediment like a time machine -- looking back in time to build a detailed picture of biodiversity over the last century at yearly resolution. By analysing biological data with climate change data and pollution levels we can identify the factors having the biggest impact on biodiversity.

"Protecting every species without impacting human production is unrealistic, but using AI we can prioritise the conservation of species that deliver ecosystem services. At the same time, we can identify the top pollutants, guiding regulation of chemical compounds with the most adverse effect. These actions can help us not only to preserve the biodiversity we have today, but potentially to improve biodiversity recovery. Biodiversity sustains many ecosystem services that we all benefit from. Protecting biodiversity mean protecting these services."

The researchers found that pollutants such as insecticides and fungicides, alongside increases in minimum temperature (a 1.2-1.5-degree increase) caused the most damage to biodiversity levels.

However, the DNA present in the sediment also showed that over the last 20 years the lake had begun to recover. Water quality improved as agricultural land use declined in the area surrounding the lake. Yet, whereas the overall biodiversity increased, the communities were not the same as in the (semi)pristine phase. This is concerning as different species can deliver different ecosystem services, and therefore their inability to return to a particular site can prevent the reinstatement of specific services.

Niamh Eastwood, lead author and PhD student at the University of Birmingham said: "The biodiversity loss caused by this pollution and the warming water temperature is potentially irreversible. The species found in the lake 100 years ago that have been lost will not all be able to return. It is not possible to restore the lake to its original pristine state, even though the lake is recovering. This research shows that if we fail to protect biodiversity, much of it could be lost forever."

Dr Jiarui Zhou, co-lead author and Assistant Professor in Environmental Bioinformatics at the University of Birmingham, said: "Learning from the past, our holistic models can help us to predict the likely loss of biodiversity under a 'business as usual' and other pollution scenarios. We have demonstrated the value of AI-based approaches for understanding historic drivers of biodiversity loss. As new data becomes available, more sophisticated AI models can be used to further improve our predictions of the causes of biodiversity loss."

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New recipes for origin of life may point way to distant, inhabited planets

Life on a faraway planet -- if it's out there -- might not look anything like life on Earth. But there are only so many chemical ingredients in the universe's pantry, and only so many ways to mix them. A team led by scientists at the University of Wisconsin-Madison has exploited those limitations to write a cookbook of hundreds of chemical recipes with the potential to give rise to life.

Their ingredient list could focus the search for life elsewhere in the universe by pointing out the most likely conditions -- planetary versions of mixing techniques, oven temperatures and baking times -- for the recipes to come together.

The process of progressing from basic chemical ingredients to the complex cycles of cell metabolism and reproduction that define life, the researchers say, requires not only a simple beginning but also repetition.

"The origin of life really is a something-from-nothing process," says Betül Kaçar, a NASA-supported astrobiologist and UW-Madison professor of bacteriology. "But that something can't happen just once. Life comes down to chemistry and conditions that can generate a self-reproducing pattern of reactions."

Chemical reactions that produce molecules that encourage the same reaction to happen again and again are called autocatalytic reactions. In a new study published Sept. 18 in the Journal of the American Chemical Society, Zhen Peng, a postdoctoral researcher in the Kaçar laboratory, and collaborators compiled 270 combinations of molecules -- involving atoms from all groups and series across the periodic table -- with the potential for sustained autocatalysis.

"It was thought that these sorts of reactions are very rare," says Kaçar. "We are showing that it's actually far from rare. You just need to look in the right place."

The researchers focused their search on what are called comproportionation reactions. In these reactions, two compounds that include the same element with different numbers of electrons, or reactive states, combine to create a new compound in which the element is in the middle of the starting reactive states.

To be autocatalytic, the outcome of the reaction also needs to provide starting materials for the reaction to occur again, so the output becomes a new input says Zach Adam, a co-author of the study and a UW-Madison geoscientist studying the origins of life on Earth. Comproportionation reactions result in multiple copies of some of the molecules involved, providing materials for the next steps in autocatalysis.

"If those conditions are right, you can start with relatively few of those outputs," Adam says. "Every time you take a turn of the cycle you spit out at least one extra output which speeds up the reaction and makes it happen even faster."

Autocatalysis is like a growing population of rabbits. Pairs of rabbits come together, produce litters of new rabbits, and then the new rabbits grow up to pair off themselves and make even more rabbits. It doesn't take many rabbits to soon have many more rabbits.

Looking for floppy ears and fuzzy tails out in the universe, however, probably isn't a winning strategy. Instead, Kaçar hopes chemists will pull ideas from the new study's recipe list and test them out in pots and pans simulating extraterrestrial kitchens.

"We will never definitively know what exactly happened on this planet to generate life. We don't have a time machine," Kaçar says. "But, in a test tube, we can create multiple planetary conditions to understand how the dynamics to sustain life can evolve in the first place."

Kaçar leads a NASA-supported consortium called MUSE, for Metal Utilization & Selection Across Eons. Her lab will focus on reactions including the elements molybdenum and iron, and she is excited to see what others cook up from the most exotic and unusual parts of the new recipe book.

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2023 Global Heat Wave: July brought the hottest three weeks observed so far

The first three weeks of July 2023 have been the hottest global three-week period so far. In the summer months of 2023, twice as many people in Germany were exposed to daily temperatures of 35 degrees and higher than the average from 1980 to 1999. This is obvious from a study published recently by Karlsruhe Institute of Technology (KIT). Researchers from KIT's Center for Disaster Management and Risk Reduction Technology (CEDIM) report that the European population's exposure to heat was highest in Italy.

In the summer of the year 2023, several hot spells of variable length and intensity occurred partly simultaneously in different regions of the northern hemisphere. In their "Untersuchung der globalen Hitzewelle im Jahr 2023" (investigation of the global heat wave in 2023), researchers of the Forensic Disaster Analysis (FDA) Task Force Group of KIT's CEDIM analyzed the record temperatures reached and the population's exposure to heat.

Ocean Surface Temperatures in June 2023 Were as High as Never Before since records began

In some regions, previous all-time record temperatures were exceeded by far, in other areas new daily or monthly records were recorded. In June 2023, global mean ocean surface temperatures were as high as never before. As regards the Earth's surface, including landmass, June 2023 has been the warmest June since 1850. On a global scale, the first three weeks of July 2023 were the hottest three-week period ever. The daily record, a global surface temperature of 17.08 degrees Celsius was reached on July 6, closely followed by July 5 and 7 with 17.07 degrees Celsius each. In July 2023, extreme temperatures and new country records -- official confirmation by the World Meteorological Organization (WMO) is still pending -were reached in the Mediterranean countries, including North Africa and the Middle East. Record-breaking temperatures were also reported by the USA, Canada, and China.

"For a big temperature anomaly to develop over a longer term, a long-lasting and unusually large-scale flow pattern is required," says Dr. Andreas Schäfer from the FDA Task Force Group of CEDIM. Pressure distribution in the middle troposphere at about 5.5 kilometers altitude plays an important role, as it influences upper airflow and the associated air mass transport. "In July 2023, extraordinarily persistent high-pressure areas prevailed in the regions affected by the high temperatures. Here, descending air masses contributed significantly to warming and the local development of the heat wave," Schäfer says.

The researchers also studied the population's exposure to heat. In Germany, about seven million people were exposed to daily maximum temperatures higher than 25 degrees Celsius. These were about 40 percent more than the average number of the years 1980 to 1999. The number of persons exposed to daily temperatures of 35 degrees Celsius and higher even doubled to about 206,000. Compared to previous decades, heat exposure during the summer months was also much higher in Italy, Greece, Spain, the USA, China, and India.

Italy Reached Heat Records of More than 40 Degrees Celsius

In Europe, Italy suffered from the biggest heat by far. Here, new record heats of more than 40 degrees Celsius were measured. While only 4000 people per day had been exposed to such high temperatures from 1980 to 1999, this number increased to more than 127,000 in 2023. To counteract the negative impacts of heat exposure on human health, state institutions adopted action plans and implemented various adaptation strategies, including the installation of public wells and water dispenser systems. In Germany, such systems can mostly be found in conurbations. (or)

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Roots are capable of measuring heat on their own

Plant roots have their own thermometer to measure the temperature of the soil around them and they adjust their growth accordingly. Through extensive experiments, a team led by Martin Luther University Halle-Wittenberg (MLU), was able to demonstrate that roots have their own temperature sensing and response system. In a new study in The EMBO Journal, the scientists also provide a new explanation for how roots themselves detect and react to higher temperatures. The results could help develop new approaches for plant breeding.

The researchers used climate chambers to investigate how the plant model organism thale cress and the two crops cabbage and tomatoes react to rising ambient temperatures. They increased the ambient temperature from 20 to 28°C (68 to 82.4 degrees Fahrenheit). "Until now, it was assumed that the plant shoot controlled the process for the entire plant and acted as a long-distance transmitter that signalled to the root that it should alter its growth," says Professor Marcel Quint from the Institute of Agricultural and Nutritional Sciences at MLU. His team has now been able to disprove this through extensive experiments in cooperation with researchers from the Leibniz Institute of Plant Biochemistry (IPB), ETH Zurich and the Max Planck Institute for Plant Breeding Research in Cologne. In one experiment, scientists cut off the shoot of the plants but allowed the roots to continue to grow. "We found that the roots were not affected by this and grew at elevated temperatures in the same way as on plants with intact shoots. The higher temperature stimulated cell division and the roots became significantly longer," says Quint. The team also used mutant plants whose shoots could no longer detect and respond to higher temperatures. Those were grafted onto roots without this defect. Here, too, the roots were able to react to the heat in the soil, even though the shoot did nothing.

The researchers found in all of their experiments that root cells increased the production of the growth hormone auxin, which was then transported to the root tips. There, it stimulated cell division and enabled the roots to reach further down into the soil. "As heat and drought usually occur in tandem, it makes sense for the plants to tap into deeper and cooler soil layers that contain water," Quint explains.

Scientists have understood how plant shoots react to higher temperatures for some time. Their cells also produce more auxin, but the plant reacts differently than its roots. The cells in the shoot stretch, the stalk grows taller, and the leaves become narrower and grow farther apart.

The study also provides new insights for plant breeding. "In view of climate change, root growth is becoming more and more important for breeding. Understanding the molecular basis for temperature-dependent root growth might help to effectively equip plants against drought stress and achieve stable yields in the long term," says Quint. Quint's team will continue its work in this field of research in the coming years. A few weeks ago, the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) granted him around 500,000 euros for a new research project on precisely this topic.

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Hotter sand from microplastics could affect sea turtle development

New research from Florida State University published in Frontiers in Marine Science found that extreme concentrations of microplastics could increase the temperature of beach sand enough to threaten the development of incubating sea turtles.

Sea turtles play a vital role in the marine ecosystem, and for these oceangoing reptiles to thrive, they need healthy beaches where their eggs can incubate successfully.

"Sea turtle sex, fitness and hatchling success is influenced by temperature," said lead author Mariana Fuentes, an associate professor in FSU's Department of Earth, Ocean and Atmospheric Science. "Not much is known on how the presence of microplastic affects the thermal profile of sand. Understanding how changes to the environment could affect the temperature of nesting grounds is important for monitoring the future of these keystone species."

Researchers mixed sand from beaches at the FSU Coastal and Marine Laboratory with black and white microplastic. Concentrations of microplastic ranged from 5% to 30% of the total volume of the sediment sample. Then they recorded temperatures from July through September 2018 by burying digital thermometers at the same depth at which loggerhead sea turtles typically lay their eggs.

They found that samples with higher microplastic concentrations had greater increases in temperature, with the sample containing 30% black microplastic pieces having the highest mean difference in temperature. Those samples were 0.58 degrees Celsius warmer than the control group, an increase that could potentially significantly alter sea turtle hatchling sex ratios, physiological performance, and mortality of embryos.

The good news from the study is that the 30% concentration of microplastics in those samples equates to about 9.8 million pieces per cubic meter, a higher concentration than has been currently found on beaches worldwide. Current research has found the highest reported concentrations collected from beaches is about 1.8 million pieces per cubic meter.

But the amount of microplastics at nesting sites has only recently been explored. It could be higher in locations that haven't been studied yet, and demand for plastic is forecast to increase in the future.

At nesting grounds where incubating eggs are near a 29-degree Celsius boundary -- below which most hatchlings are male, and above which most hatchlings are female -- smaller concentrations of plastic could be enough to push the temperature beyond a crucial threshold.

"Sea turtle eggs are sensitive to temperature, and microplastics are another factor adding to the heat they face," Fuentes said. "This study gives us a baseline for future research on how they are affecting the nesting environment."

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Climate change to push species over abrupt tipping points

Climate change is likely to abruptly push species over tipping points as their geographic ranges reach unforeseen temperatures, finds a new study led by a UCL researcher.

The new Nature Ecology & Evolution study predicts when and where climate change is likely to expose species across the globe to potentially dangerous temperatures.

The research team from UCL, University of Cape Town, University of Connecticut and University at Buffalo analysed data from over 35,000 species of animals (including mammals, amphibians, reptiles, birds, corals, fish, cephalopods and plankton) and seagrasses from every continent and ocean basin, alongside climate projections running up to 2100.

The researchers investigated when areas within each species’ geographical range will cross a threshold of thermal exposure, defined as the first five consecutive years where temperatures consistently exceed the most extreme monthly temperature experienced by a species across its geographic range over recent history (1850-2014).

Once the thermal exposure threshold is crossed, the animal is not necessarily going to die out, but there is no evidence that it is able to survive the higher temperatures – that is, the research projects that for many species there could be an abrupt loss of habitat due to future climate change.

The researchers found a consistent trend that for many animals, the thermal exposure threshold will be crossed for much of their geographic range within the same decade.

Lead author Dr Alex Pigot (UCL Centre for Biodiversity & Environment Research, UCL Biosciences) said: “It is unlikely that climate change will gradually make environments more difficult for animals to survive in. Instead, for many animals, large swaths of their geographic range are likely to become unfamiliarly hot in a short span of time.

“While some animals may be able to survive these higher temperatures, many other animals will need to move to cooler regions or evolve to adapt, which they likely cannot do in such short timeframes.

“Our findings suggest that once we start to notice that a species is suffering under unfamiliar conditions, there may be very little time before most of its range becomes inhospitable, so it’s important that we identify in advance which species may be at risk in coming decades.”

The researchers found that the extent of global warming makes a big difference: if the planet warms by 1.5°C, 15% of species they studied will be at risk of experiencing unfamiliarly hot temperatures across at least 30% of their existing geographic range in a single decade, but this doubles to 30% of species at 2.5°C of warming.

Dr Pigot added: “Our study is yet another example of why we need to urgently reduce carbon emissions to mitigate the harmful effects climate change is having on animals and plants, and avoid a massive extinction crisis.”

The researchers hope that their study could help with targeting conservation efforts, as their data provides an early warning system showing when and where particular animals are likely to be at risk.

Co-author Dr Christopher Trisos (African Climate and Development Initiative, University of Cape Town) said: “In the past we’ve had snapshots to show the impact of climate change, but here we are presenting the data more like a film, where you can see the changes unfold over time. This shows that for many species the risk is a bit like everything, everywhere, all at once. By animating this process, we hope to help direct conservation efforts before it’s too late, while also showing the potentially catastrophic consequences of letting climate change continue unchecked.”

The researchers say that this pattern of abrupt exposure may be an inevitable feature of living on a round planet – because of the shape of the Earth, there is more area available to species in environments near the hot end of what they are used to, such as in low-lying areas or near the equator.

A previous study by the same lead authors found that even if we stop climate change so that global temperatures peak and start to decline, the risks to biodiversity could persist for decades after. In another analysis similar to the current study, they found that many species facing unfamiliar temperatures will be living alongside other animals experiencing similar temperature shocks, which could pose grave risks to local ecosystem function.

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Extremely hot days are warming twice as fast as average summer days in North-West Europe

New study analysed data on near-surface air temperatures recorded for North-West Europe over the past 60 years. The findings show that the maximum temperature of the hottest days is increasing at twice the rate of the maximum temperature of average summer days. The results highlight the need for urgent action by policy makers to adapt essential infrastructure to the impacts of climate change.

New research led by the University of Oxford has found that climate change is causing the hottest days in North-West Europe to warm at double the rate of average summer days. The difference in trends is most pronounced for England, Wales, and Northern France. Worryingly, while current climate models accurately predict the rate of warming for average days, they underestimate the rate at which the hottest days are warming compared to observations.

According to lead researcher Dr Matthew Patterson, from the University of Oxford's Department of Physics, the results indicate that extreme heat events -- such as the UK's record-breaking heatwave last summer -- are likely to become more regular. Dr Patterson said: 'These findings underline the fact that the UK and neighbouring countries are already experiencing the effects of climate change, and that last year's heatwave was not a fluke. Policy makers urgently need to adapt their infrastructure and health systems to cope with the impacts of higher temperatures.'

For the study, published today in Geographical Research Letters, Dr Patterson analysed data from the past 60 years (1960-2021) recording the maximum daily temperature, provided by the European Centre for Medium-Range Weather Forecasts.

Although the maximum recorded temperature varied between years, the overall trend clearly showed that the hottest days for North-West Europe had warmed at twice the rate of average summer days. For England and Wales, the average summer day increased by approximately 0.26°C per decade, whilst the hottest day increased by around 0.58°C per decade. However, this faster warming of the hottest days was not observed to this extent elsewhere in the Northern Hemisphere.

The reason causing this faster warming of the hottest days relative to average summer days is not yet understood. According to Dr Patterson, this may be due to the hottest summer days in North-West Europe often being linked to hot air transported north from over Spain. Because Spain is warming faster than North-West Europe, this means that air carried in from this region is ever more extreme relative to the ambient air in North-West Europe. The hottest days of 2022, for instance, were driven by a plume of hot air carried north from Spain and the Sahara. However, further research is needed to verify this.

Dr Patterson added: 'Understanding the warming rate of the hottest days will be important if we are to improve climate model simulation of extreme events and make accurate predictions about the future intensity of such events. If our models underestimate the rise in extreme temperatures over the coming decades, we will underestimate the impacts this will have.'

Extreme heat has significant negative impacts on many different aspects of society, including energy and transport infrastructure, and agriculture. It also exacerbates conditions including respiratory and cardiovascular diseases, putting a strain on health services.

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Global research reveals countries where record-breaking heatwaves are likely to cause most harm

A new study has highlighted under-prepared regions across the world most at risk of the devastating effects of scorching temperatures.

The University of Bristol-led research, published today in Nature Communications, shows that unprecedented heat extremes combined with socioeconomic vulnerability puts certain regions, such as Afghanistan, Papua New Guinea, and Central America,most in peril.

Countries yet to experience the most intense heatwaves are often especially susceptible, as adaptation measures are often only introduced after the event. A high chance of record-breaking temperatures, growing populations, and limited healthcare and energy provision, increase the risks.

Beijing and Central Europe are also on the list of hotspots, as if record-breaking heatwaves occurred in these densely populated regions millions of people would be adversely affected.

In light of the findings, the researchers are calling for policy makers in hotspot regions to consider relevant action plans to reduce the risk of deaths and associated harms from climate extremes.

Lead author, climate scientist Dr Vikki Thompson at the University of Bristol Cabot Institute for the Environment, said: "As heatwaves are occurring more often we need to be better prepared. We identify regions that may have been lucky so far -- some of these regions have rapidly growing populations, some are developing nations, some are already very hot. We need to ask if the heat action plans for these areas are sufficient."

The researchers used extreme value statistics -- a method to estimate the return periods of rare events -- and large datasets from climate models and observations to pinpoint regions globally where temperature records are most likely to be broken soonest and the communities consequently in greatest danger of experiencing extreme heat.

The researchers also cautioned that statistically implausible extremes, when current records are broken by margins that seemed impossible until they occurred, could happen anywhere. These unlikely events were found to have transpired in almost a third (31%) of the regions assessed where observations were deemed reliable enough between 1959 and 2021, such as the 2021 Western North America heatwave.

Co-author Dann Mitchell, Professor in Atmospheric Sciences at the University of Bristol Cabot Institute for the Environment, said: "Being prepared saves lives. We have seen some of the most unexpected heatwaves around the world lead to heat-related deaths in the tens of thousands. In this study, we show that such record smashing events could occur anywhere. Governments around the world need to be prepared."

Human-induced climate change is causing an increase in the frequency, intensity, and duration of heatwaves, which have the potential to lead to thousands more excess deaths globally.

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New programmable smart fabric responds to temperature and electricity

A new smart material developed by researchers at the University of Waterloo is activated by both heat and electricity, making it the first ever to respond to two different stimuli.

The unique design paves the way for a wide variety of potential applications, including clothing that warms up while you walk from the car to the office in winter and vehicle bumpers that return to their original shape after a collision.

Inexpensively made with polymer nano-composite fibres from recycled plastic, the programmable fabric can change its colour and shape when stimuli are applied.

"As a wearable material alone, it has almost infinite potential in AI, robotics and virtual reality games and experiences," said Dr. Milad Kamkar, a chemical engineering professor at Waterloo. "Imagine feeling warmth or a physical trigger eliciting a more in-depth adventure in the virtual world."

The novel fabric design is a product of the happy union of soft and hard materials, featuring a combination of highly engineered polymer composites and stainless steel in a woven structure.

Researchers created a device similar to a traditional loom to weave the smart fabric. The resulting process is extremely versatile, enabling design freedom and macro-scale control of the fabric's properties.

The fabric can also be activated by a lower voltage of electricity than previous systems, making it more energy-efficient and cost-effective. In addition, lower voltage allows integration into smaller, more portable devices, making it suitable for use in biomedical devices and environment sensors.

"The idea of these intelligent materials was first bred and born from biomimicry science," said Kamkar, director of the Multi-scale Materials Design (MMD) Centre at Waterloo.

"Through the ability to sense and react to environmental stimuli such as temperature, this is proof of concept that our new material can interact with the environment to monitor ecosystems without damaging them."

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Temperature of a rocky exoplanet measured

An international team of researchers has used NASA's James Webb Space Telescope to measure the temperature of the rocky exoplanet TRAPPIST-1 b. The measurement is based on the planet's thermal emission: heat energy given off in the form of infrared light detected by Webb's Mid-Infrared Instrument (MIRI). The result indicates that the planet's dayside has a temperature of about 500 kelvins (roughly 450 degrees Fahrenheit) and suggests that it has no significant atmosphere.

This is the first detection of any form of light emitted by an exoplanet as small and as cool as the rocky planets in our own solar system. The result marks an important step in determining whether planets orbiting small active stars like TRAPPIST-1 can sustain atmospheres needed to support life. It also bodes well for Webb's ability to characterize temperate, Earth-sized exoplanets using MIRI.

"These observations really take advantage of Webb's mid-infrared capability," said Thomas Greene, an astrophysicist at NASA's Ames Research Center and lead author on the study published today in the journal Nature. "No previous telescopes have had the sensitivity to measure such dim mid-infrared light."

Rocky Planets Orbiting Ultracool Red Dwarfs

In early 2017, astronomers reported the discovery of seven rocky planets orbiting an ultracool red dwarf star (or M dwarf) 40 light-years from Earth. What is remarkable about the planets is their similarity in size and mass to the inner, rocky planets of our own solar system. Although they all orbit much closer to their star than any of our planets orbit the Sun - all could fit comfortably within the orbit of Mercury - they receive comparable amounts of energy from their tiny star.

TRAPPIST-1 b, the innermost planet, has an orbital distance about one hundredth that of Earth's and receives about four times the amount of energy that Earth gets from the Sun. Although it is not within the system's habitable zone, observations of the planet can provide important information about its sibling planets, as well as those of other M-dwarf systems.

"There are ten times as many of these stars in the Milky Way as there are stars like the Sun, and they are twice as likely to have rocky planets as stars like the Sun," explained Greene. "But they are also very active - they are very bright when they're young, and they give off flares and X-rays that can wipe out an atmosphere."

Co-author Elsa Ducrot from the French Alternative Energies and Atomic Energy Commission (CEA) in France, who was on the team that conducted earlier studies of the TRAPPIST-1 system, added, "It's easier to characterize terrestrial planets around smaller, cooler stars. If we want to understand habitability around M stars, the TRAPPIST-1 system is a great laboratory. These are the best targets we have for looking at the atmospheres of rocky planets."

Detecting an Atmosphere (or Not)

Previous observations of TRAPPIST-1 b with the Hubble and Spitzer space telescopes found no evidence for a puffy atmosphere, but were not able to rule out a dense one.

One way to reduce the uncertainty is to measure the planet's temperature. "This planet is tidally locked, with one side facing the star at all times and the other in permanent darkness," said Pierre-Olivier Lagage from CEA, a co-author on the paper. "If it has an atmosphere to circulate and redistribute the heat, the dayside will be cooler than if there is no atmosphere."

The team used a technique called secondary eclipse photometry, in which MIRI measured the change in brightness from the system as the planet moved behind the star. Although TRAPPIST-1 b is not hot enough to give off its own visible light, it does have an infrared glow. By subtracting the brightness of the star on its own (during the secondary eclipse) from the brightness of the star and planet combined, they were able to successfully calculate how much infrared light is being given off by the planet.

Measuring Minuscule Changes in Brightness

Webb's detection of a secondary eclipse is itself a major milestone. With the star more than 1,000 times brighter than the planet, the change in brightness is less than 0.1%.

"There was also some fear that we'd miss the eclipse. The planets all tug on each other, so the orbits are not perfect," said Taylor Bell, the post-doctoral researcher at the Bay Area Environmental Research Institute who analyzed the data. "But it was just amazing: The time of the eclipse that we saw in the data matched the predicted time within a couple of minutes."

The team analyzed data from five separate secondary eclipse observations. "We compared the results to computer models showing what the temperature should be in different scenarios," explained Ducrot. "The results are almost perfectly consistent with a blackbody made of bare rock and no atmosphere to circulate the heat. We also didn't see any signs of light being absorbed by carbon dioxide, which would be apparent in these measurements."

This research was conducted as part of Webb Guaranteed Time Observation (GTO) program 1177, which is one of eight programs from Webb's first year of science designed to help fully characterize the TRAPPIST-1 system. Additional secondary eclipse observations of TRAPPIST-1 b are currently in progress, and now that they know how good the data can be, the team hopes to eventually capture a full phase curve showing the change in brightness over the entire orbit. This will allow them to see how the temperature changes from the day to the nightside and confirm if the planet has an atmosphere or not.

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Study reveals new clues about how 'Earth's thermostat' controls climate

Rocks, rain and carbon dioxide help control Earth's climate over thousands of years -- like a thermostat -- through a process called weathering. A new study led by Penn State scientists may improve our understanding of how this thermostat responds as temperatures change.

"Life has been on this planet for billions of years, so we know Earth's temperature has remained consistent enough for there to be liquid water and to support life," said Susan Brantley, Evan Pugh University Professor and Barnes Professor of Geosciences at Penn State. "The idea is that silicate rock weathering is this thermostat, but no one has ever really agreed on its temperature sensitivity."

Because many factors go into weathering, it has been challenging to use results of laboratory experiments alone to create global estimates of how weathering responds to temperature changes, the scientists said.

The team combined laboratory measurements and soil analysis from 45 soil sites around the world and many watersheds to better understand weathering of the major rock types on Earth and used those findings to create a global estimate for how weathering responds to temperature.

"When you do experiments in the laboratory versus taking samples from soil or a river, you get different values," Brantley said. "So what we tried to do in this research is look across those different spatial scales and figure out how we can make sense of all this data geochemists around the world been accumulating about weathering on the planet. And this study is a model for how we can do that."

Weathering represents part of a balancing act of carbon dioxide in Earth's atmosphere. Volcanoes have emitted large amounts of carbon dioxide through Earth's history, but instead of turning the planet into a hot house, the greenhouse gas is slowly removed via weathering.

Rain takes the carbon dioxide from the atmosphere and creates a weak acid that falls to Earth and wears away silicate rocks the surface. The byproducts are carried by streams and rivers to the ocean where the carbon is eventually locked away in sedimentary rocks, the scientists said.

"It has long been hypothesized that the balance between carbon dioxide entering the atmosphere from volcanoes and being pulled out by weathering over millions of years holds the temperature of the planet relatively constant," Brantley said. "The key is when there is more carbon dioxide in the atmosphere and the planet gets hotter, weathering goes faster and pulls more carbon dioxide out. And when the planet is cooler, weathering slows down."

But much remains unknown about how sensitive weathering is to changing temperatures, partly because of the long spatial and time scales involved.

"In a soil profile, you are seeing a picture of soil where the camera shutter was open for sometimes a million years -- there are integrated processes happening for a million years and you're trying to compare that with a two-year flask experiment," Brantley said.

Brantley said the field of critical zone science -- which examines landscapes from the tallest vegetation to the deepest groundwater -- has helped scientists better understand the complex interactions that influence weathering.

For example, rocks must fracture for water to get in cracks and start breaking down the materials. For that to happen, the rock must have large, exposed surface areas, and that is less likely to happen in regions where soil is deeper.

"It's only when you start crossing spatial and time scales that you start seeing what's really important," Brantley said. "Surface area is really important. You can measure all the rate constants you want for that solution in the lab, but until you can tell me how does surface area form out there in the natural system, you are never going to be able to predict the real system."

The scientists reported in the journal Science that temperature sensitivity measurements in the laboratory were lower than estimates from soils and rivers in their study. Using observations from the lab and field sites, they upscaled their findings to estimate the global temperature dependance of weathering.

Their model may be helpful for understanding how weathering will respond to future climate change, and in evaluating human-made attempts to increase weathering to draw more carbon dioxide from the atmosphere -- like carbon sequestration.

"One idea has been to enhance weathering by digging up a lot of rock, grinding it, transporting it and putting it out in the fields to let weathering happen," Brantley said. "And that will work -- it's already working. The problem is, it's a very slow process."

Though warming may speed up weathering, pulling all the carbon dioxide out of the atmosphere that humans have added could take thousands or hundreds of thousands of years, the scientists said.

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What crocodile DNA reveals about the Ice Age

What drives crocodile evolution? Is climate a major factor or changes in sea levels? Determined to find answers to these questions, researchers from McGill University discovered that while changing temperatures and rainfall had little impact on the crocodiles' gene flow over the past three million years, changes to sea levels during the Ice Age had a different effect.

"The American crocodile tolerates huge variations in temperature and rainfall. But about 20,000 years ago - when much of the world's water was frozen, forming the vast ice sheets of the last glacial maximum - sea levels dropped by more than 100 metres. This created a geographical barrier that separated the gene flow of crocodiles in Panama," says postdoctoral fellow José Avila-Cervantes, working under the supervision of McGill professor Hans Larsson.

The researchers point out that the crocodiles are good swimmers, but they can't travel long distances on land. As a result, the Caribbean and Pacific crocodile populations were isolated from each other, and consequently have undergone different genetic mutations.

The team compared the climate tolerance of living populations of American crocodiles (Crocodylus acutus) to the paleoclimate estimates for the region over the past 3 million years - the time span of extreme climate variation during the Ice Age.

"This is one of the first times Ice Age effects have been found in a tropical species. It's exciting to discover effects of the last Ice Age glaciation still resonate in the genomes of Pacific and Caribbean American crocodiles today," says Larsson, Professor of Biology at the Redpath Museum of McGill University.

"Discovering that these animals would have easily tolerated the climate swings of the Ice Age speaks to their resilience over geological time. Only humans in recent decades of hunting and land development seem to really affect crocodiles," he says. The findings offer new insight into how environmental drivers affect genetic evolution and where conservation efforts of particular crocodile populations in Panama should be focused.

From Science Daily

Mimicking an enigmatic property of circadian rhythms through an artificial chemical clock

Circadian rhythms are natural, internal oscillations that synchronize an organism's behaviors and physiological processes with their environment. These rhythms normally have a period of 24 hours and are regulated by internal chemical clocks that respond to cues from outside the body, such as light.

Although well studied in animals, plants, and bacteria, circadian rhythms all share an enigmatic property -- the oscillation period is not significantly affected by temperature, even though the rate of most biochemical reactions changes exponentially with temperature. This clearly indicates that some sort of temperature-compensation mechanism is at play. Interestingly, some scientists have managed to replicate such temperature-invariant qualities in certain oscillating chemical reactions. However, these reactions are often troublesome and require extremely precise adjustments on the reacting chemicals.

But what if there was a simpler way to achieve temperature compensation in an oscillating chemical reaction? In a recent study published in Scientific Reports, a team of researchers including Assistant Professor Yuhei Yamada of Tokyo Institute of Technology (Tokyo Tech), Japan, came up with a clever idea for a temperature compensation mechanism using a reaction called the Belousov-Zhabotinsky (BZ) oscillating reaction.

The key to their approach lies in soft, temperature-responsive gels made from poly(N-isopropylacrylamide), or 'PNIPAAm' for short, in which the BZ reaction can occur. These gels consist of polymeric strands that can accommodate a certain volume of solvent. However, because these gels shrink as temperature increases, the amount of solvent contained in the gel decreases as temperature rises.

The researchers exploited this property of PNIPAAm gels by adding ruthenium (Ru) sites on its constituent polymers. The periodic nature of the particular BZ reaction the researchers studied relies partially on the back-and-forth oxidation and reduction of ruthenium (Ru) ions. Thus, the speed of this reaction is affected by the relative concentrations of solvent and Ru. Because the PNIPAAm gels can accommodate less solvent when they shrink, the relative concentration of Ru in the gels increases with temperature.

As the research team demonstrated through experimental measurements and a thorough mathematical analysis, the abovementioned effects combine to form a temperature-compensation mechanism that renders the period of the BZ reaction unaffected by shifts in temperature. "The prepared BZ gels exhibited temperature compensability just like the circadian rhythms observed in living organisms," remarks Yamada.

Overall, this study demonstrates a completely new way to achieve temperature compensation in artificial biological clocks based on periodic reactions. Intriguingly, it's even possible that similar temperature-compensation mechanisms using temperature-responsive soft bodies exist in biological systems in nature, as Yamada explains: "Our study suggests that temperature compensation can be naturally self-sustainable through the output system of circadian machinery. This may explain why temperature compensation is a universal property of circadian rhythms seen in animals, plants, and bacteria, regardless of the molecular species involved."

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The rich meteorology of Mars studied in detail from the Perseverance rover

Perseverance is a NASA autonomous vehicle that arrived at the Jezero Crater (the bed of an ancient, now dried-up lake on Mars) on 18 February 2021. The rover is equipped with seven novel, complex scientific instruments dedicated to exploring the planet's surface in search of signs of possible past life, collecting and depositing samples to be brought back to Earth, testing new technologies for use in human exploration, and studying the planet's atmosphere in detail. With regard to the aim of studying the atmosphere, the MEDA (Mars Environmental Dynamics Analyzer) instrument has been obtaining novel results. MEDA's lead researcher is José Antonio Rodríguez-Manfredi of the Centre for Astrobiology (CAB) in Madrid, and it has had the participation of a team from the UPV/EHU's Planetary Sciences Research Group. The instrument comprises a set of sensors that measure temperature, pressure, wind, humidity and properties of the dust that is always present in suspension in the Mars atmosphere.

Perseverance has now completed its investigation of the atmosphere throughout the first Martian year (which lasts approximately two Earth years). A preview of the results, which appears on the cover, is published today in the January issue of the journal Nature Geoscience. Specifically, the UPV/EHU team, formed by Agustín Sánchez-Lavega, Ricardo Hueso, Teresa del Río-Gaztelurrutia and the PhD student Asier Munguira, has led the study of the seasonal and daily cycles of temperature and pressure, as well as their significant variations on other time scales resulting from very different processes.

Throughout the seasons, the average air temperature at the Jezero Crater, located near the planet's equator, is around minus 55 degrees Celsius, but varies greatly between day and night, with typical differences of around 50 to 60 degrees. In the middle of the day, the heating of the surface generates turbulent movements in the air as a result of the rise and fall of air masses (convection) which cease in the evening, when the air settles.

Pressure sensors, on the other hand, show in detail the seasonal change of the tenuous Martian atmosphere produced by the melting and freezing of atmospheric carbon dioxide at the polar caps, as well as by a complex, variable daily cycle, modulated by thermal tides in the atmosphere. "The pressure and temperature of the Mars atmosphere oscillate with periods of the Martian solar day (somewhat longer than the Earth's, it averages at 24 hrs 39.5 min) and with their submultiples, following the daily cycle of sunshine greatly influenced by the amount of dust and the presence of clouds in the atmosphere," says Agustín Sánchez-Lavega, professor at the Faculty of Engineering -- Bilbao (EIB) and co-researcher on the Mars 2020 mission.

Both sensors are also detecting dynamic phenomena in the atmosphere that occur in the vicinity of the rover, for example, those produced by the passage of whirlwinds known as "dust devils" because of the dust they sometimes kick up, or the generation of gravity waves whose origin is not yet well understood. "The dust devils are more abundant at Jezero than elsewhere on Mars, and can be very large, forming whirlwinds more than 100 metres in diameter. With MEDA we have been able to characterise not only their general aspects (size and abundance) but also to unravel how these whirlwinds function," says Ricardo Hueso, lecturer at the Faculty of Engineering -- Bilbao (EIB).

MEDA has also detected the presence of storms thousands of kilometres away, very similar in origin to terrestrial storms, as shown by the images from orbiting satellites, and which move along the edge of the north polar cap, formed by the deposition of carbonic snow.

Within the rich variety of phenomena studied, MEDA has been able to characterise in detail the changes that have taken place in the atmosphere by one of the dreaded dust storms, such as the one that developed in early January 2022. Its passage over the rover led to abrupt changes in temperature and pressure accompanied by strong gusts of wind, which kicked up dust and hit the instruments, damaging one of the wind sensors.

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Global warming reaches central Greenland

At high elevations of the Greenland Ice Sheet, the years 2001 to 2011 were 1.5 °C warmer than in the 20th century and represent the warmest decade in the last thousand years.

A temperature reconstruction from ice cores of the past 1,000 years reveals that today's warming in central-north Greenland is surprisingly pronounced. The most recent decade surveyed in a study, the years 2001 to 2011, was the warmest in the past 1,000 years, and the region is now 1.5 °C warmer than during the 20th century, as researchers led by the Alfred Wegener Institute just report in the journal Nature. Using a set of ice cores unprecedented in length and quality, they reconstructed past temperatures in central-north Greenland and melting rates of the ice sheet.

The Greenland Ice Sheet plays a pivotal part in the global climate system. With enormous amounts of water stored in the ice (about 3 million cubic kilometres), melt and resulting sea-level rise is considered a potential tipping point. For unmitigated global emissions rates ('business as usual'), the ice sheet is projected to contribute up to 50 centimetres to global mean sea-level by 2100. Weather stations along the coast have been recording rising temperatures for many years. But the influence of global warming on the up to 3,000 m elevated parts of the ice sheet have remained unclear to due to the lack of long-term observations. In a study now published in Nature, experts from the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI) present clear evidence that effects of global warming have reached the remote, high-elevation areas of central-north Greenland.

"The time series we recovered from ice cores now continuously covers more than 1,000 years, from year 1000 to 2011. This data shows that the warming in 2001 to 2011 clearly differs from natural variations during the past 1,000 years. Although grimly expected in the light of global warming, we were surprised by how evident this difference really was," says AWI glaciologist Dr Maria Hörhold, lead author of the study. Together with colleagues from AWI and the University of Copenhagen's Niels Bohr Institute, she analysed the isotope composition in shallow ice cores gathered in central-north Greenland during dedicated AWI expeditions.

Previous ice cores obtained at co-located sites starting in the 1990s, did not indicate clear warming in central-north Greenland, despite rising global mean temperatures. Part of the reason is substantial natural climate variability in the region.

The AWI researchers have now extended the previous datasets up to winter 2011/2012 by a dedicated redrilling effort, recovering time series unprecedented length and quality. The temperatures were reconstructed by using consistently one single method for the entire record in the lab: measuring concentrations of stable oxygen isotopes within the ice, which vary with the temperatures prevailing at times of ice formation. Previous studies had to draw on a range of different climate archives and combine results to reconstruct temperature, introducing much larger uncertainties in the assessment of natural variability.

In addition to the temperature, the team reconstructed the melt production of the ice sheet. Melting has increased substantially in Greenland since the 2000s and now significantly contributes to global sea-level rise. "We were amazed to see how closely temperatures inland are connected to Greenland-wide meltwater drainage -- which, after all, occurs in low-elevation areas along the rim of the ice sheet near the coast," says Maria Hörhold.

In order to quantify this connection between temperatures in high-elevation parts and melting along the edges of the ice sheet, the authors used data from a regional climate model for the years 1871 to 2011 and satellite observations of ice-mass changes for the years 2002 to 2021 from the GRACE/GRACE-FO gravimetry missions. This allowed them to convert the temperature variations identified in the ice cores into melting rates and provide estimates for the past 1,000 years. This represents an important dataset for climate research: better understanding of the melt dynamics of the ice sheet in the past improves projections of related future sea-level rise; reduced uncertainties in projections is one step to help optimize adaptation measures.

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