Fluid mechanics of the Dead Sea
The Dead Sea, Earth’s lowest exposed surface and its deepest hypersaline lake, presents a rare convergence of extreme environmental conditions that make it a natural laboratory for fluid mechanics research. Led by Professor Eckart Meiburg at UC Santa Barbara, in collaboration with Nadav Lensky of the Geological Survey of Israel, recent research delves into how these unique conditions give rise to massive salt deposits, or “salt giants,” actively forming on the lakebed.
As the lake’s water level declines at a rate of roughly one meter per year due to evaporation and reduced inflow from the Jordan River, the concentration of dissolved salt increases, frequently reaching saturation. This sets the stage for halite (NaCl) to precipitate and settle to the bottom. During summer, a sharp stratification forms between warm, salty surface water and the cooler, denser deep layer. This thermohaline layering triggers a phenomenon known as double diffusion, where descending salt-rich fingers transport salt downward, occasionally precipitating halite as they cool. In contrast, winter overturning of the water column causes widespread halite precipitation throughout the entire depth.
These seasonal and spatial patterns explain how thick halite layers accumulate, particularly in deeper parts of the lake. Surface waves, internal mixing and even subsurface springs contribute to more complex salt structures such as domes and chimneys. In addition to illuminating the mechanics behind ancient geological salt giants, this research offers insights into sediment transport, coastline evolution and the broader impacts of declining water levels in terminal lakes under climate stress.
How device type influences digital access and equity
In a recent study led by Amy Gonzales, a communication professor at UCSB, and graduate researcher Ceciley Zhang, researchers examined the real-world impact of different types of digital access on people’s ability to benefit from the internet. Drawing from national survey data, they found that owning a desktop or laptop computer is significantly more influential in enabling meaningful online engagement, such as applying for jobs, accessing healthcare portals or navigating government services than simply having home internet access or relying on smartphones.
The study challenges the assumption that connectivity alone bridges the digital divide. While broadband access remains important, it is the type of device people use that often determines whether they can fully take advantage of online opportunities. In contrast to computers, smartphones are frequently associated with more limited, entertainment-based or social uses, and in some cases, even hinder functional tasks due to small screen sizes or poor usability for complex forms.
The findings carry important implications for public policy, especially in underserved communities. Current government programs tend to prioritize internet infrastructure, but Gonzales and Zhang emphasize the need for initiatives that also provide access to larger-screen devices. Without this, many low-income or otherwise disadvantaged groups may remain digitally excluded from critical services, despite being connected.
The researchers underscore that digital equity is a multidimensional issue involving access, devices and digital literacy. Ensuring that vulnerable populations, such as seniors, low-income families and those with limited education, have the right tools to navigate an increasingly digital world is essential for equitable social and economic participation.
River channel patterns
A major study led by researchers at UCSB reveals why some rivers follow a single path while others split into multiple branching channels. Using over three decades of global satellite imagery, Austin Chadwick and his colleagues tracked the dynamic behavior of 84 rivers across the world. Their findings show that rivers form multiple channels when bank erosion exceeds sediment deposition. This imbalance causes the river to widen and eventually split, forming a braided or multi-threaded system.
The researchers discovered that in single-thread rivers, erosion and deposition are balanced, allowing the river to maintain a stable width and follow gentle, meandering curves. In contrast, multi-threaded rivers are shaped by constant reshuffling as channels widen, split and reconfigure as sediment from eroded banks is deposited on the riverbed, forming islands and bars.
This insight settles a long-standing debate in geomorphology and provides a simple, predictive model based on the erosion-deposition balance, rather than a complex mix of variables. The study also offers practical tools for river restoration, including a formula to estimate how much space and time a river needs to return to its natural state. The model could help guide more cost-effective and ecologically sound restoration projects, especially in regions where past human intervention has altered river dynamics.
The work highlights how understanding natural river behavior is essential in a changing climate and in planning resilient infrastructure. It also underscores the potential for many currently single-threaded rivers to return to their historically braided forms if given enough room and time.
