The deep ocean can be a breathtaking sight to behold, resembling a real-life snow globe. As organic particles from plant and animal matter on the surface sink downward, they combine with dust and other material to create “marine snow,” a crucial component in cycling carbon and nutrients through the world’s oceans. However, researchers from Brown University and the University of North Carolina at Chapel Hill have recently uncovered surprising new insights into how these particles settle in the ocean.

In a study published in Proceedings of the National Academy of Sciences, they found that the speed at which particles sink is not solely determined by resistive drag forces from the fluid, but also by their ability to absorb salt relative to their volume. This discovery challenges conventional wisdom and could have significant implications for understanding natural carbon cycling and even engineering ways of speeding up carbon capture.

“It basically means that smaller particles can sink faster than bigger ones,” said Robert Hunt, a postdoctoral researcher in Brown’s School of Engineering who led the work. “That’s exactly the opposite of what you’d expect in a fluid with uniform density.”

The researchers created a linearly stratified body of water to test their model and found that particles with high porosity tended to sink faster than those with lower porosity, regardless of their size. This means that elongated particles actually sink faster than spherical ones of the same volume.

“We ended up with a pretty simple formula where you can plug in estimates for different parameters – the size of the particles or speed at which the liquid density changes – and get reasonable estimates of the sinking speed,” said Daniel Harris, an associate professor of engineering at Brown who oversaw the work. “There’s value in having predictive power that’s readily accessible.”

The study grew out of prior work by Hunt and Harris investigating neutrally buoyant particles, and their new findings have the potential to revolutionize our understanding of how particles settle in complex ecological settings.

“We’re not trying to replicate full oceanic conditions,” Harris said. “The approach in our lab is to boil things down to their simplest form and think about the fundamental physics involved in these complex phenomena. Then we can work back and forth with people measuring these things in the field to understand where these fundamentals are relevant.”

Harris hopes to connect with oceanographers and climate scientists to see what insights these new findings might provide, and other co-authors of the research were Roberto Camassa and Richard McLaughlin from UNC Chapel Hill. The research was funded by the National Science Foundation and the Office of Naval Research.

Plants and trees have long been known to extend their roots into the earth in search of nutrients and water. However, a new study has revealed that many plants develop a second, deeper layer of roots – often more than three feet underground – to access additional nourishment. This discovery, published in the journal Nature Communications, changes our understanding of how ecosystems respond to changing environmental conditions.

The research team, led by Mingzhen Lu from New York University’s Department of Environmental Studies, used data from the National Ecological Observatory Network (NEON) to examine rooting depth. By digging deeper than traditional ecological studies – up to 6.5 feet below the surface – they detected additional root patterns in diverse climate zones and ecosystem types.

The scientists’ work focused on three key questions: How do plants acquire resources? What strategies do they employ to adapt to environmental change? And what are the implications for carbon storage?

Their findings were striking: nearly 20 percent of the studied ecosystems had roots that peaked twice across depth – a phenomenon called “bimodality.” In these cases, plants developed a second, deeper layer of roots, often aligning with nutrient-rich soil layers. This suggests that plants have been growing in previously unknown ways to exploit additional sustenance.

The study’s lead author, Mingzhen Lu, observes that the current understanding of roots is “literally too shallow.” By not looking deep enough, we may have overlooked a natural carbon storage mechanism deep underground. The research opens up new avenues for inquiry into how bimodal rooting patterns impact the dynamics of nutrient flow, water cycling, and long-term soil carbon stock.

As scientists and policymakers look to manage ecosystems in a rapidly changing climate, they must consider these overlooked deep soil layers. The study concludes that plants may already be naturally mitigating climate change more actively than we’ve realized – we just need to dig deeper to fully understand their potential.

Scientists at ETH Zurich have made a groundbreaking discovery – they’ve created a living building material that captures CO2 from the air using photosynthetic bacteria. This innovative material has the potential to revolutionize the way we build and sustain our cities.

The research team, led by Professor Mark Tibbitt, has successfully incorporated cyanobacteria into a printable gel, creating a structure that grows and actively removes carbon dioxide from the atmosphere. The special thing about this living material is its ability to store carbon not only in biomass but also in minerals, making it an effective solution for carbon sequestration.

“We utilize this ability specifically in our material,” says Yifan Cui, one of the lead authors of the study. “Cyanobacteria are among the oldest life forms in the world. They are highly efficient at photosynthesis and can utilize even the weakest light to produce biomass from CO2 and water.”

The team has also optimized the geometry of the structures using 3D printing processes, increasing the surface area and promoting the flow of nutrients to keep the cyanobacteria alive and efficient.

This living material has significant implications for urban planning. The researchers envision it as a low-energy and environmentally friendly approach that can bind CO2 from the atmosphere and supplement existing chemical processes for carbon sequestration.

“We want to investigate how the material can be used as a coating for building façades to bind CO2 throughout the entire life cycle of a building,” says Professor Tibbitt.

The concept has already caught the attention of architects, who have taken up the idea and realized initial interpretations in an experimental way. Two installations at the Architecture Biennale in Venice and Milan showcase the potential of this living material in sustainable urban planning.

One installation uses the printed structures as living building blocks to construct tree-trunk-like objects that can bind up to 18 kg of CO2 per year, about as much as a 20-year-old pine tree in the temperate zone. The other installation investigates the potential of living materials for future building envelopes, using microorganisms to form a deep green patina on wooden shingles.

The photosynthetic living material was created thanks to an interdisciplinary collaboration within the framework of ALIVE (Advanced Engineering with Living Materials), an ETH Zurich initiative that promotes collaboration between researchers from different disciplines in order to develop new living materials for a wide range of applications.