Diminishing Arctic Sea Ice Has Lasting Impacts on Global Climate

Source: University at Albany, State University of New York

As the impacts of climate change are felt around the world, no area is experiencing more drastic changes than the northern polar region. Studies have shown the Arctic is warming at two to three times as fast as the rest of the planet, resulting in a rapid loss of its sea ice volume.

The loss of sea ice, declining at an average rate of about 13 percent per decade, is having a long-lasting climatic impact in the Arctic and beyond, according to a new study published this month in Nature Communications.

The research team, led by University at Albany atmospheric scientist Aiguo Dai, analyzed observational data and climate model simulations to show how fluctuations in Arctic Sea ice cover are able to amplify multi-decadal variations in surface temperatures not only in the Arctic but also in the North Atlantic Ocean.

Their results indicate that recent – and future – decreases in sea ice cover have a significant influence on global climate.

“Through our study, we demonstrated for the first time that fluctuations in sea ice-air interactions can greatly enlarge or amplify multi-decadal climate variations not only in the Arctic, but also the North Atlantic,” said Dai, a distinguished professor in the Department of Atmospheric and Environmental Sciences.

Researchers Discover New Function Performed by Nearly Half of Brain Cells

Scientists say the discovery of a new function by cells known as astrocytes opens a whole new direction for neuroscience research.
Illustration Credit: Siena Fried

Researchers at Tufts University School of Medicine have discovered a previously unknown function performed by a type of cell that comprises nearly half of all cells in the brain.

The scientists say this discovery in mice of a new function by cells known as astrocytes opens a whole new direction for neuroscience research that might one day lead to treatments for many disorders ranging from epilepsy to Alzheimer’s to traumatic brain injury.

It comes down to how astrocytes interact with neurons, which are fundamental cells of the brain and nervous system that receive input from the outside world. Through a complex set of electrical and chemical signaling, neurons transmit information between different areas of the brain and between the brain and the rest of the nervous system.

Until now, scientists believed astrocytes were important, but lesser cast members in this activity. Astrocytes guide the growth of axons, the long, slender projection of a neuron that conducts electrical impulses. They also control neurotransmitters, chemicals that enable the transfer of electrical signals throughout the brain and nervous system. In addition, astrocytes build the blood-brain barrier and react to injury.

But they did not seem to be electrically active like the all-important neurons—until now.

Bird populations in eastern Canada declining due to forest ‘degradation,’ research shows

Mixed forest at left, spruce plantation at right.
Credit: by Debora Carr

Bird species that live in wooded areas are under stress from human-caused changes to forest composition, according to new research led by Oregon State University that quantifies the effects of forest “degradation” on bird habitat.

“Reducing forest loss has been the main focus of conservation policy to date, which is well justified because it has a strong negative effect on biodiversity,” said Matt Betts of the OSU College of Forestry. “But the effects of changing the composition and age of forest via timber management have traditionally been very difficult to measure at large scales and thus have been largely ignored. Our work shows population declines in many bird species in eastern Canada are due to habitat loss caused by forestry activities.”

Findings by the international collaboration led by Betts were published today in Nature Ecology and Evolution.

The scientists looked at the degree to which forest degradation – the reduction or loss of biological complexity – in the form of clearcutting and then thinning or replanting single tree species affected bird habitat and long-term trends in bird populations.

The study area was the Acadian Forest in Canada’s maritime provinces. Breeding habitat loss occurred for 66% of the forest’s 54 most common bird species from 1985 to 2020 and was strongly associated with the loss of older forests.

Unchecked global emissions on track to initiate mass extinction of marine life

Princeton University researchers report that unless greenhouse gas emissions are curbed, marine biodiversity could be on track to plummet to levels not seen since the extinction of the dinosaurs. The study authors modeled future marine biodiversity under projected climate scenarios and found that species such as dolphinfish (shown) would be imperiled as warming oceans decrease the ocean’s oxygen supply while increasing marine life’s metabolic demand for it. 
Credit: Evan Davis

As greenhouse gas emissions continue to warm the world’s oceans, marine biodiversity could be on track to plummet within the next few centuries to levels not seen since the extinction of the dinosaurs, according to a recent study in the journal Science by Princeton University researchers.

Princeton University researchers report that unless greenhouse gas emissions are curbed, marine biodiversity could be on track to plummet to levels not seen since the extinction of the dinosaurs. The study authors modeled future marine biodiversity under projected climate scenarios and found that species such as dolphinfish (shown) would be imperiled as warming oceans decrease the ocean’s oxygen supply while increasing marine life’s metabolic demand for it.

The paper’s authors modeled future marine biodiversity under different projected climate scenarios. They found that if emissions are not curbed, species losses from warming and oxygen depletion alone could come to mirror the substantial impact humans already have on marine biodiversity by around 2100. Tropical waters would experience the greatest loss of biodiversity, while polar species are at the highest risk of extinction, the authors reported.

Large bodies helped extinct marine reptiles with long necks swim, study finds

3D models of aquatic tetrapods
Credit: S. Gutarra Díaz

Scientists at the University of Bristol have discovered that body size is more important than body shape in determining the energy economy of swimming for aquatic animals.

This study, published today in Communications Biology, shows that big bodies help overcome the excess drag produced by extreme morphology, debunking a long-standing idea that there is an optimal body shape for low drag.

One important finding of this research is that the large necks of extinct elasmosaurs did add extra drag, but this was compensated for by the evolution of large bodies.

Tetrapods or ‘four-limbed vertebrates’, have repeatedly returned to the oceans over the last 250 million years, and they come in many shapes and sizes, ranging from streamlined modern whales over 25 meters in length, to extinct plesiosaurs, with four flippers and extraordinarily long necks, and even extinct fish-shaped ichthyosaurs.

Dolphins and ichthyosaurs have similar body shapes, adapted for moving fast through water producing low resistance or drag. On the other hand, plesiosaurs, who lived side by side with the ichthyosaurs in the Mesozoic Era, had entirely different bodies. Their enormous four flippers which they used to fly underwater, and variable neck lengths, have no parallel amongst living animals. Some elasmosaurs had really extreme proportions, with necks up to 20 feet (6 meters) long. These necks likely helped them to snap up quick-moving fish, but were also believed to make them slower.

Boeing Unveils First T-7A Red Hawk Advanced Trainer Jet to be Delivered to the U.S. Air Force

The first T-7A Red Hawk advanced trainer has rolled out of the production facility in St. Louis, Missouri. Ushering in a new era of training for U.S. Air Force fighter and bomber pilots. The jets have red tails to honor the legendary Tuskegee Airmen who flew their aircraft with red tails during World War II. First jets scheduled to arrive at Joint Base San Antonio- Randolph next year.
Photo Credit- Eric Shindelbower

Boeing [NYSE: BA] has unveiled the first T-7A Red Hawk advanced trainer jet to be delivered to the U.S. Air Force. The jet, one of 351 the U.S. Air Force plans to order, was unveiled prior to official delivery.

The fully digitally designed aircraft was built and tested using advanced manufacturing, agile software development and digital engineering technology significantly reducing the time from design to first flight. The aircraft also features open architecture software, providing growth and flexibility to meet future mission needs.

“We’re excited and honored to deliver this digitally advanced, next-generation trainer to the U.S. Air Force,” said Ted Colbert, president and CEO, Boeing Defense, Space & Security. “This aircraft is a tangible example of how Boeing, its suppliers and partners are leading the digital engineering revolution. T-7A will prepare pilots for future missions for decades to come.”

Childhood obesity increases risk of Type 1 diabetes

Being overweight in childhood increases the risk of developing type 1 diabetes in later life, according to the findings of a new study that analyzed genetic data on over 400,000 individuals. The study, co-led by researchers from the Universities of Bristol and Oxford and published today in Nature Communications, also provides evidence that being overweight over many years from childhood influences the risk of other diseases including asthma, eczema and hypothyroidism.

The number of individuals being diagnosed with type 1 diabetes has increased drastically in the last 20 years. One possible explanation is the rising prevalence of childhood obesity in an increasingly obesogenic environment. Poor diets with high fat, salt and carbohydrate may compromise early life health-promoting effects of the bacteria in the gut and pancreatic beta-cell fragility in childhood and subsequently increase type 1 diabetes risk.

In contrast to type 1 diabetes, there is irrefutable evidence that children who are overweight are more likely to develop type 2 diabetes and that weight loss can lead to its sustained remission. However, detecting reliable evidence for the factors that contribute to type 1 has been challenging, particularly given that individuals are typically diagnosed early in life before reaching adulthood.

New Study Could Help Reduce Agricultural Greenhouse Gas Emissions

Researchers developed a first-of-its-kind knowledge-guided machine learning model for agroecosystem, called KGML-ag that includes less obvious variables such as soil water content, oxygen level, and soil nitrate content related to nitrous oxide production and emission.
Credit: University of Minnesota College of Science and Engineering

A team of researchers led by the University of Minnesota has significantly improved the performance of numerical predictions for agricultural nitrous oxide emissions. The first-of-its-kind knowledge-guided machine learning model is 1,000 times faster than current systems and could significantly reduce greenhouse gas emissions from agriculture.

The research was recently published in Geoscientific Model Development, a not-for-profit international scientific journal focused on numerical models of the Earth. Researchers involved were from the University of Minnesota, the University of Illinois at Urbana-Champaign, Lawrence Berkeley National Laboratory, and the University of Pittsburgh.

Compared to greenhouse gases such as carbon dioxide and methane, nitrous oxide is not as well-known. In reality, nitrous oxide is about 300 times more powerful than carbon dioxide in trapping heat in the atmosphere. Human-induced nitrous oxide emissions (mainly from agricultural synthetic fertilizer and cattle manure) have also grown by at least 30 percent over the past four decades.

Origin of complex cells started without oxygen

Since the 1960s, many experts have argued that the emergence of eukaryotes (cells containing a clearly defined nucleus) happened in response to the oxygenation of Earth’s surface environment.

But a team led by the universities of Stanford and Exeter say recent advances in the Earth and life sciences challenge this view.

Their review says these breakthroughs "decouple" the emergence of eukaryotes (known as eukaryogenesis) from rising oxygen levels, and suggest eukaryotes in fact emerged in an anoxic (no-oxygen) environment in the ocean.

"We can now independently date eukaryogenesis and key oxygenation transitions in Earth history," said Dr Daniel Mills, of Stanford University.

"Based on fossil and biological records, the timing of eukaryogenesis does not correlate with these oxygen transitions in the atmosphere (2.22 billion years ago) or the deep ocean (0.5 billion years ago).

"Instead, mitochondria-bearing eukaryotes are consistently dated to between these two oxygenation events, during an interval of deep-sea anoxia and variable surface-water oxygenation."

The emergence of mitochondria – the energy-producing "powerhouses" of eukaryote cells – is now thought to be the defining step in eukaryogenesis.

Mitochondria have different DNA to the cells in which they live, and the new paper addresses the possible origin of this symbiotic relationship, famously championed by the biologist Lynn Margulis.

Ancient hand grenades: explosive weapons in medieval Jerusalem during Crusades

A fragment of the sphero-conical vessel that was identified as containing a possibly explosive material from Jerusalem.
Credit: Robert Mason, Royal Ontario Museum.

New analysis into the residue inside ancient ceramic vessels from 11th-12th century Jerusalem has found that they were potentially used as hand grenades.

Previous research into the diverse sphero-conical containers, which are within museums around the world, had identified that they were used for a variety of purposes, including beer drinking vessels, mercury containers, containers for oil and containers for medicines.

This latest research, led by Griffith University’s Associate Professor Carney Matheson, confirmed that some vessels did indeed contain oils and medicines, and some contained scented oils, consistent with other recent research into the use of the vessels.

However, his findings also revealed that some of the vessels contained a flammable and probably explosive material that indicated they may have been used as ancient hand grenades.

Associate Professor Matheson, from Griffith’s Australian Research Centre for Human Evolution, said the explosive material he analyzed within the vessels suggested that there may have been a locally developed ancient explosive.