The Hidden Impact of Anoxic Pockets on Sandy Shores

Human activities have dramatically increased nitrogen inputs into coastal seas, leading to a significant amount of this human-derived nitrogen being removed by microorganisms in coastal sands through denitrification. However, research has shown that this process can also occur in oxygenated sands, and scientists from the Max Planck Institute for Marine Microbiology in Bremen, Germany, have now revealed how this happens.

The scientists used a method called microfluidic imaging to visualize the diverse and uneven distribution of microbes and the oxygen dynamics on extremely small scales. “Tens of thousands of microorganisms live on a single grain of sand,” explains Farooq Moin Jalaluddin from the Max Planck Institute for Marine Microbiology. The researchers could show that some microbes consume more oxygen than is resupplied by the surrounding pore water, creating anoxic pockets on the surface of the sand grains.

These anoxic microenvironments have so far been invisible to conventional techniques but have a dramatic effect: “Our estimates based on model simulations show that anaerobic denitrification in these anoxic pockets can account for up to one-third of the total denitrification in oxygenated sands,” says Jalaluddin.

The researchers calculated how relevant this newly researched form of nitrogen removal is on a global scale and found that it could account for up to one-third of total nitrogen loss in silicate shelf sands. Consequently, this denitrification is a substantial sink for anthropogenic nitrogen entering the oceans.

In conclusion, the hidden impact of anoxic pockets on sandy shores has been revealed by scientists, highlighting the importance of these microenvironments in removing nitrogen from coastal seas and emphasizing the need to consider them when assessing the overall nitrogen budget of our planet.

Wildfires have become an increasing threat in the Western United States, with devastating effects on both public health and the environment. As these fires rage, they release enormous amounts of aerosols into the atmosphere, which can travel far and wide, impacting air quality and human health. A recent study, published in Environmental Science: Atmospheres, has shed light on the alarming consequences of wildfire smoke on air quality and the planet’s short-term weather.

The research, led by scientists Siying Lu and Andrey Khlystov from the Desert Research Institute (DRI), monitored air quality in Reno, Nevada over a 19-month period between 2017 and 2020. During this time, more than 106 wildfires impacted the city’s air, with smoke accounting for up to 65% of PM2.5 concentrations and 26% of carbon monoxide levels.

The findings reveal that fine aerosols (PM2.5), which can travel deep into lungs, increased significantly during smoky days. These particles are produced when trees and homes burn, releasing soot and other pollutants into the air. The data also showed that larger aerosols can promote cloud formation and duration by acting as nuclei for water vapor to condense around.

Furthermore, the study found higher concentrations of carbon monoxide present in Reno’s air during smoky days. This gas can reduce the ability of blood to carry oxygen to the brain and other organs. In contrast, levels of nitrogen oxides and ozone remained relatively stable during both smoky and average days.

The research team used a combination of equipment on DRI’s roof and data from a downtown Reno EPA air monitoring station to collect hourly concentrations of PM2.5, ozone, carbon monoxide, and other air pollutants. They also employed satellite images and fire location information from NASA and NOAA to verify when air pollution was caused by wildfire smoke.

The implications of this study are far-reaching. The findings suggest that wildfires can have a significant impact on local air quality, with potential effects on public health and the environment. As wildfires continue to increase in frequency and severity, it is essential to understand their impact on air quality and develop strategies to mitigate these effects.

In conclusion, the study highlights the importance of monitoring air quality during smoky days and provides valuable insights into the consequences of wildfire smoke on human health and the planet’s short-term weather. As we continue to face the challenges posed by wildfires, it is crucial that we prioritize air quality research and public health messaging to ensure a safer and healthier environment for all.

Rapid simulations of toxic particles could aid air pollution fight by providing more precise ways of monitoring air quality and predicting how these harmful substances move through the air. Researchers have developed a new computer modeling approach that significantly improves the accuracy and efficiency of simulating nanoparticles’ behavior in the air.

These tiny particles, found in exhaust fumes, wildfire smoke, and other airborne pollutants, are linked to serious health conditions such as stroke, heart disease, and cancer. Predicting how they move is notoriously difficult, making it challenging to develop effective strategies for mitigating their impact.

The new method allows researchers to calculate a key factor governing how particles travel – known as the drag force – up to 4,000 times faster than existing techniques. This breakthrough was made possible by creating a mathematical solution based on how air disturbances caused by nanoparticles fade with distance.

By applying this approach to simulations, researchers can zoom in much closer to particles without compromising accuracy. This differs from current methods, which involve simulating vast regions of surrounding air to mimic undisturbed airflow and require far more computing power.

The new approach could help better predict how these particles will behave inside the body, potentially aiding the development of improved air pollution monitoring tools. It could also inform the design of nanoparticle-based technologies, such as lab-made particles for targeted drug delivery.

The study, published in the Journal of Computational Physics, was supported by the Engineering and Physical Sciences Research Council (EPSRC). Lead author Dr Giorgos Tatsios, from the University of Edinburgh’s School of Engineering, said: “Our method allows us to simulate their behavior in complex flows far more efficiently, which is crucial for understanding where they go and how to mitigate their effects.”

Professor Duncan Lockerby, from the University of Warwick’s School of Engineering, added: “This approach could unlock new levels of accuracy in modeling how toxic particles move through the air – from city streets to human lungs – as well as how they behave in advanced sensors and cleanroom environments.”