Until now, scientists have had limited information about how much of this carbon returns to the atmosphere and how much remains trapped in the ocean. Researchers from the Alfred Wegener Institute and MARUM – Centre for Marine Environmental Sciences at the University of Bremen have now examined this process along the permafrost coast of Qikiqtaruk (Herschel Island) in Canada.

By studying sediment cores, the team found that large amounts of carbon from land are preserved in the seafloor. They also discovered that marine microorganisms behave like selective eaters, favoring fresh carbon from the ocean over older carbon released from permafrost. The findings were published in Nature Geoscience.

Vast Carbon Stores Are Beginning to Thaw

Permafrost ecosystems on Arctic land contain about 1,300 gigatonnes of organic carbon, much of it from plant remains. Another 400 gigatonnes are stored in ocean sediments and river deltas.

As the planet warms, the Arctic is heating faster than any other region. This rapid temperature rise is causing frozen ground to thaw and coastlines to break apart. Carbon that was previously locked in the soil can then reach the Arctic Ocean through rivers and coastal erosion.

“Consequently, up to 0.02 gigatonnes are entering the sea each year, and according to forecasts, this outflow could rise by 70 to 150 percent by the year 2100,” says Dr. Manuel Ruben, lead author of the study from the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI). “However, how much of this is released back into the atmosphere as a greenhouse gas and how much is stored in the seabed has, until now, been largely unknown.”

Resolving that uncertainty is important because scientists need to know where the carbon ultimately ends up to estimate how thawing permafrost could affect the climate.

Sediment Cores Reveal Where the Carbon Goes

To investigate, the researchers collected sediment cores from several locations off the coast of Herschel Island. These cores contain layers of material deposited over roughly 50 years.

The results showed that only a relatively small share of the carbon swept into the ocean becomes part of the active carbon cycle.

“Although the sea here carries away huge quantities of organic carbon from the coast, surprisingly little of it ends up in the ocean’s active carbon cycle,” says Manuel Ruben. “Microorganisms convert around ten percent of the organic carbon from the sediments into gases, which rise into the water and can then enter our atmosphere.”

Most of the remaining carbon stays buried in the seabed.

Chemical Clues Track Microbial Activity

The scientists analyzed the composition of the sediment cores and measured how quickly material from the permafrost accumulated on the ocean floor.

They also studied dissolved inorganic carbon found in tiny spaces between sediment particles, known as pore water. These measurements reveal how much CO2 microorganisms have released after consuming organic material.

The isotopic makeup of the pore water helped the team determine where that material came from.

“Carbon isotopes represent our atomic indicators that can identify the food source of the microorganisms,” says Prof. Gesine Mollenhauer, a geochemist at the AWI and co-spokesperson for the ‘The Ocean Floor – Earth’s Unexplored Interface’ cluster of Excellence. “The ¹³C isotope, for example, tells us whether they have consumed carbon from land or from the sea. By way of the ¹⁴C isotope, we were able to determine whether the single-celled organisms preferred old organic carbon from permafrost or fresh organic carbon from algae remains.”

“Gourmet” Bacteria Prefer Fresh Carbon

The results suggest that the organisms living in the sediment are not equally interested in every type of carbon.

“The sediment is home to ‘gourmet’ bacteria that apparently prefer fresh carbon stemming from, for example, more recent algal remains over the ‘old’ carbon from permafrost deposits,” explains Gesine Mollenhauer.

Because the microbes favor fresh marine material, older carbon from thawing permafrost may contribute less to atmospheric greenhouse gas levels than scientists once feared.

However, the researchers caution that the full picture is not yet clear.

“However, we do need further research here. This is because some of the organic carbon from the permafrost may already have been broken down before it reaches the seabed.”

Coastal Carbon Could Reshape Arctic Ecosystems

The movement of carbon from land into the ocean may affect more than greenhouse gas emissions. It can also change the chemistry and biology of coastal waters that support food resources for local communities.

Sediment released by coastal erosion can reduce the amount of sunlight entering the water. Freshly eroded fragments make the coastal ocean cloudy, while dissolved organic carbon can darken the water.

That loss of light can affect single-celled organisms such as algae, which need sunlight to produce biomass and oxygen. This primary production supports a wider food web that includes fish, crustaceans and seals.

The researchers plan to explore these connections further during the international ‘Arctic Pulse’ campaign scheduled for 2027. Scientists will carry out coordinated observations from the Polarstern research icebreaker, aboard AWI research aircraft and at sites on land. Their goal is to understand how rapid environmental change is transforming Arctic ecosystems.

Improving Arctic Climate Models

“Our study shows, more precisely than ever before, how much carbon is safely stored in the seabed – and just how much of the decomposed material actually originates from the old permafrost,” says Manuel Ruben. “This provides an important foundation for climate models that can predict the consequences of permafrost thawing for the global climate.”

Scientists have now identified a protein pathway that may help connect aging with the harmful protein buildup seen in disorders such as Huntington’s disease and amyotrophic lateral sclerosis (ALS).

Searching for the Link Between Aging and Brain Disease

A research team led by Professor Dr. David Vilchez at the CECAD Cluster of Excellence for Aging Research investigated this connection using the small nematode worm Caenorhabditis elegans. The researchers examined a signaling pathway that becomes increasingly active with age and contributes to the accumulation of abnormal proteins.

Their study, titled “The aging factor EPS8 induces disease-related protein aggregation through RAC signaling hyperactivation,” was published in Nature Aging.

The team concentrated on EPS8, an aging-associated protein, and the signaling pathways it controls. Previous research showed that EPS8 accumulates as worms grow older and activates damaging stress responses that shorten their lifespan.

EPS8 Drives Toxic Protein Buildup

The researchers found that higher EPS8 levels and increased activity in its signaling pathways promote pathological protein aggregation and neurodegeneration. Both are defining features of age-associated neurodegenerative conditions, including Huntington’s disease and ALS.

When the scientists reduced EPS8 activity, toxic protein aggregates no longer accumulated as readily. The treatment also helped preserve neuronal function in worm models of both diseases.

“We are delighted to uncover a molecular mechanism that could shed light on to how aging contributes to diseases like ALS and Huntington’s,” says first author Dr. Seda Koyuncu. “For years, we’ve known that age is the major common risk factor for different neurodegenerative diseases. However, how exactly age-related changes contribute to these diseases remains largely unknown. This study may contribute to filling in a part of that puzzle.”

Similar Results in Human Cells

EPS8 and the signaling molecules associated with it have been preserved throughout evolution and are also found in human cells. This allowed the researchers to determine whether the mechanism they observed in worms might also be relevant to human disease.

Reducing EPS8 levels in human cell models of Huntington’s disease and ALS produced results similar to those seen in C. elegans. The intervention prevented the accumulation of toxic protein aggregates in the cells.

“It’s incredibly exciting that the mechanisms we uncovered in C. elegans are also conserved in human cell models,” says Professor Dr. David Vilchez, highlighting how the use of simpler model organisms like the nematode worm can prove extremely useful to uncover disease mechanisms relevant to humans.

A Potential Target for Future Treatments

Scientists still do not know precisely how increased EPS8 activity causes toxic proteins to aggregate. Even so, the results address an important gap in neurodegenerative disease research by identifying a direct molecular connection between aging and neurodegeneration.

The findings also point to EPS8 and its signaling partners as possible targets for future therapies. Treatments aimed at this pathway could potentially slow or prevent the progression of ALS, Huntington’s disease, and other brain disorders associated with aging.

“Alzheimer’s is a condition that remains recalcitrant to the scientific community’s attempts at developing a cure or preventative treatment,” said Daniel Schultz, a former postdoctoral fellow in the Vanderbilt University Warren Center for Neuroscience Drug Discovery.

Gaps in Alzheimer’s Biology

One major obstacle to developing better therapies is that researchers still do not fully understand the biology behind Alzheimer’s disease. The same problem affects research into many other neurological diseases and neurodevelopmental disorders.

Scientists have identified genes and proteins that may contribute to these conditions, but studying them can be extremely difficult when researchers lack a reliable way to change how those biological targets behave.

One approach involves using tool compounds. These chemicals interact with particular proteins and either raise or reduce their activity. Although many tool compounds are unsuitable for use as medicines because they may affect unintended targets or cause toxicity, they are still highly valuable for investigating what a protein does. That knowledge can become an important early step toward developing new treatments.

Targeting the TAOK1 Protein

In a study published in ACS Chemical Neuroscience, Schultz and co-first author Lauren Parr, a Ph.D. student in the Department of Pharmacology, developed a compound that selectively inhibits TAOK-1. The protein has been linked to Alzheimer’s disease, but it has remained poorly understood partly because researchers have lacked suitable compounds for studying it.

Most of the work was carried out at the WCNDD under the leadership of Executive Director Craig Lindsley. The WCNDD is a clinical-stage biotech start-up within Vanderbilt. Its drug discovery pipeline currently includes five compounds in phase I clinical trials.

The center is also a founding pillar of the new Vanderbilt Institute for Therapeutic Advances, a next-generation drug discovery institute that is also led by Lindsley.

To find useful compounds, Schultz, Parr, and other WCNDD researchers created a large collection of related molecules. Each one had a slightly different structure. The team then evaluated how the compounds affected TAOK-1 and assessed whether they had properties considered desirable in potential drugs.

“This project showcased the strength of the WCNDD’s drug discovery infrastructure,” Schultz said.

The First Selective TAOK1 Inhibitor

The collaboration led to the discovery of VU6083859, the first selective inhibitor of TAOK-1. The compound could provide a starting point for research aimed at developing future Alzheimer’s disease treatments.

Another molecule produced an unexpected result. The compound, named VU6080195, activated all three proteins in the TAOK family rather than inhibiting them.

“Our understanding of TAOK proteins largely centers around their inhibition, so we are excited at the prospect of studying the neurological effects of increasing their activity,” Schultz said. “As scientists, we can get lost in planning our projects to the last detail and expecting things to go a certain way, so it was quite fun to see this unexpected result.”

Schultz hopes the two compounds will encourage more researchers to investigate the TAOK protein family. So far, these proteins have received relatively little attention in in vivo models.

New Tools for Alzheimer’s Research

A deeper understanding of disease biology can improve the chances of finding effective treatments. With these two compounds now available, neuroscientists can examine how the TAOK protein family functions and explore its links to Alzheimer’s and other neurological diseases.

The findings could eventually help researchers identify new treatment strategies and perhaps contribute to the long-term search for a cure.

The paper “Discovery of VU6083859, a TAOK1 Selective Inhibitor, and VU6080195, a pan-TAOK Activator” was published in ACS Chemical Neuroscience.

The research used funding from the William K. Warren Foundation and received support from the Zenobia and Mark Godschalk Alzheimer’s Research Endowment, the Helen H. and Morris D. Hartman, MD 1910, Neurological Research Fund, the Warren Center for Neuroscience Drug Discovery, and the Vanderbilt Institute for Therapeutic Advances.

A new study in the Journal of Cosmology and Astroparticle Physics (JCAP) examined what would happen if dark matter experienced an additional attractive force. The results were surprisingly counterintuitive. Although the force causes dark matter to gather more efficiently, it usually does not accelerate the growth of cosmic structure. Instead, it tends to slow that growth.

Why Scientists Are Considering a Dark Force

Interest in a possible “dark force” has increased as highly precise observations of the Universe have produced results that do not always align perfectly.

Measurements of cosmic expansion and the development of galaxies and other large structures sometimes appear to tell slightly different stories. Some observations of the distant Universe suggest that expansion may have proceeded somewhat more slowly in the past than the standard cosmological model predicts.

At the same time, studies of the cosmic microwave background have long suggested that matter could be more tightly clustered across the largest scales of the Universe than expected.

These differences are relatively small, but they have encouraged scientists to ask whether the standard model of cosmology may be missing an important ingredient.

One possibility is that dark matter particles feel an extra force that ordinary matter cannot detect. Because the interaction would operate only within the dark matter sector, researchers refer to it as a “dark force.” Such an interaction could potentially affect both the Universe’s expansion and the formation of galaxies and larger cosmic structures.

“What we really know about dark matter has so far been learned only through its gravitational effects,” says Zachary Weiner, a researcher at the Perimeter Institute for Theoretical Physics, corresponding author for the study. “That leaves open the possibility that dark matter might have additional interactions that are hidden from ordinary matter.”

Testing a Force Beyond Gravity

The research team investigated a group of theoretical models in which dark matter particles interact through a long-range force in addition to gravity.

Using theoretical calculations together with cosmological data, the scientists studied how this hidden interaction would influence the history of cosmic expansion and the growth of large-scale structure.

At first, the expected result seems straightforward. If dark matter particles attract each other through another force, they should assemble into clumps more quickly. That stronger clustering might also appear to explain observations suggesting that the Universe contains denser structures than predicted.

“The first thing you would expect is that giving dark matter an additional attractive force should make structures grow faster,” says Weiner. “But another effect comes into play at the same time.”

A Surprising Effect on Cosmic Growth

In the models examined by the researchers, the extra force does make dark matter cluster more effectively. However, it also changes how dark matter behaves as the Universe expands.

The same process causes dark matter particles to effectively lose mass over time. This reduction weakens their gravitational influence, offsetting the stronger attraction produced by the hidden force.

As a result, the enhanced clustering does not create a stronger gravitational imprint on the cosmic microwave background. In most cases, the combined effect actually suppresses the growth of cosmic structure.

Implications for DESI and Dark Energy Models

The findings could matter for theories that extend beyond dark matter alone. Some explanations proposed for recent measurements from the Dark Energy Spectroscopic Instrument (DESI) involve similar interactions among dark matter particles.

According to the researchers, the newly identified mechanism is likely to influence many of those more complicated models as well. Any theory involving a hidden attractive force may need to account for the possibility that dark matter becomes effectively lighter as the Universe evolves.

More precise measurements from upcoming observatories and cosmic surveys could help scientists determine which hidden interactions dark matter might possess and which possibilities observations can rule out.

“The Universe is often more subtle than our intuition,” says Weiner. “That’s exactly why we have to keep testing these ideas.”

The findings support once weekly brisk interval walking as a practical therapeutic option for adults with central obesity, especially those who have difficulty fitting several workouts into their schedules. The study was published in Nature Communications.

A More Practical Approach to Reducing Body Fat

Obesity is a chronic health condition involving an unhealthy buildup of body fat. Fat that accumulates around the abdomen is especially concerning because it is associated with cardiovascular disease, metabolic disorders, and a higher risk of premature death.

Exercise plays an important role in managing obesity and offers a wide range of health benefits. Even so, many people, particularly those living with obesity, struggle to maintain regular physical activity over time.

Interval training alternates between more vigorous periods of exercise and lower-intensity periods of active recovery. Research has shown that it can be a time-efficient way to reduce overall body fat and visceral fat compared with continuous exercise performed at a moderate intensity.

Most exercise recommendations call for interval training three days each week. That schedule may be difficult for people with demanding jobs, family responsibilities, limited time, or restricted access to exercise facilities.

Previous research has suggested that a “weekend warrior” pattern, in which most weekly exercise is completed over one or two days, can still produce health benefits. However, there has been relatively little evidence showing whether interval training remains effective when concentrated into a single weekly session.

Professor Parco Siu Ming-fai, Professor and Head of Division of Kinesiology at the School of Public Health, HKUMed, said it was important to determine whether once weekly interval training could match the results of a traditional three-session schedule and provide a more accessible alternative.

One Session Versus Three

From September 2021 to September 2024, the HKUMed team carried out a randomized trial in Hong Kong involving 315 Chinese adults aged 18 or older. All participants were overweight and had central obesity.

Participants were assigned to one of three groups. One group completed interval training once each week, another completed interval training three times each week, and the third served as a control group.

The control group took part in a 2.5-hour health education session every two weeks for four months. Both exercise groups completed a total of 75 minutes of interval training each week. One group performed the full amount in a single session, while the other divided it across three sessions.

Researchers measured body fat using dual-energy X-ray absorptiometry at three stages: before the program began (baseline), after 16 weeks (post-intervention), and at 32 weeks (four-month post-intervention follow-up).

Similar Fat Loss and Fitness Benefits

At the 16-week assessment, both interval training groups showed similar improvements. Participants who exercised once per week and those who exercised three times per week reduced total body fat mass, body fat percentage, and waist circumference. Both groups also improved their cardiorespiratory fitness compared with the control group.

“While thrice-weekly interval training remains a commonly recommended approach for the therapeutic management of excess adiposity, our findings show that once-weekly interval training offers similar benefits and represents a practical exercise strategy,” said Professor Siu. “For many adults with central obesity who struggle to balance work, study, family and other commitments, time constraints are a primary barrier to exercising multiple days per week.”

“Instead of relying solely on high-frequency exercise prescriptions, once-weekly interval training can be considered a feasible and effective alternative,” added Professor Siu.

The study was led by Professor Parco Siu Ming-fai, Professor and Head of Division of Kinesiology at the School of Public Health, HKUMed. The co-first authors were Dr. Leung Chit-kay and Mr. Joshua Bernal, both from the same School.

The research was supported by the General Research Fund of the Research Grants Council, the University Grants Committee of Hong Kong, China, and the Seed Fund for Basic Research, HKU.