The study published in Science Advances by NASA scientists has revealed a significant correlation between the strength of the Earth’s magnetic field and fluctuations in atmospheric oxygen levels over the past 540 million years. This groundbreaking research suggests that processes deep within the Earth’s core might be influencing habitability on the planet’s surface.

At the heart of this phenomenon lies the Earth’s magnetic field, which is generated by the flow of molten material in the planet’s interior. Like a giant electromagnet, this process creates a dynamic field that has been fluctuating over time. The authors of the study point out that the role of magnetic fields in preserving the atmosphere is still an area of active research.

To uncover the hidden link between the Earth’s core and life-sustaining oxygen, scientists have analyzed magnetized minerals that record the history of the magnetic field. These minerals, formed when hot materials rise with magma at gaps between tectonic plates, retain a record of the surrounding magnetic field as long as they are not reheated too severely. By studying these ancient rocks and minerals, researchers can deduce historic oxygen levels based on their chemical contents.

The databases compiled by geophysicists and geochemists have provided valuable information on both the Earth’s magnetic field and oxygen levels over comparable ranges. Until now, no scientists had made a detailed comparison of the records. The findings of this study suggest that the two datasets are remarkably similar, with the planetary magnetic field following similar rising and falling patterns as oxygen in the atmosphere for nearly half a billion years.

The implications of this discovery are profound, suggesting that complex life on Earth might be connected to the interior processes of the planet. Coauthor Weijia Kuang said, “Earth is the only known planet that supports complex life. The correlations we’ve found could help us understand how life evolves and how it’s connected to the interior processes of the planet.”

Further research aims to examine longer datasets to see if the correlation extends farther back in time. The study also plans to investigate the historic abundance of other chemicals essential for life, such as nitrogen. As for the specific causes linking the Earth’s deep interior to life on the surface, scientist Kopparapu said, “There’s more work to be done to figure that out.”

The West Coast of the United States is no stranger to massive floods caused by atmospheric rivers. These powerful storms bring much-needed moisture to the region, but also pose a significant threat to communities and ecosystems. A new study has shed light on the hidden trigger behind these devastating events: wet soils that cannot absorb more water when a storm hits.

The research, published in the Journal of Hydrometeorology, analyzed over 43,000 atmospheric river storms across 122 watersheds on the West Coast between 1980 and 2023. The findings reveal that flood peaks were 2-4.5 times higher on average when soils were already wet. This means that even weaker storms can generate major floods if their precipitation meets a saturated Earth.

Lead author Mariana Webb, completing her Ph.D. at DRI and the University of Nevada, Reno, explained that flooding from any event is not just a function of storm size and magnitude but also depends on what’s happening on the land surface. The study demonstrates the key role that pre-event soil moisture can have in moderating flood events.

Interestingly, flood magnitudes do not increase linearly as soil moisture increases. There’s a critical threshold of soil moisture wetness above which you start to see much larger flows. This research also untangled the environmental conditions of regions where soil moisture has the largest influence on flooding.

In arid places like California and southwestern Oregon, storms that hit when soils are already saturated are more likely to cause floods. In contrast, in lush Washington and the interior Cascades and Sierra Nevada regions, watersheds tend to have deeper soils and snowpack, leading to a higher water storage capacity. Although soil saturation can still play a role in driving flooding in these areas, accounting for soil moisture is less valuable for flood management because soils are consistently wet or insulated by snow.

The study highlights the importance of integrating land surface conditions into impact assessments for atmospheric rivers. Webb worked with DRI ecohydrologist Christine Albano to produce the research, building on Albano’s extensive expertise studying atmospheric rivers, their risks, and their impacts on the landscape.

While soil saturation is widely recognized as a key factor in determining flood risk, Mari’s work helps to quantify the point at which this level of saturation leads to large increases in flood risk across different areas along the West Coast. Advances in weather forecasting allow us to see atmospheric rivers coming toward the coast several days before they arrive. By combining atmospheric river forecast information with knowledge of how close the soil moisture is to critical saturation levels for a given watershed, we can further improve flood early warning systems.

Increased monitoring in watersheds identified as high-risk, including real-time soil moisture observations, could significantly enhance early warning systems and flood management as atmospheric rivers become more frequent and intense. By tailoring flood risk evaluations to a specific watershed’s physical characteristics and climate, the study could improve flood-risk predictions.

The accumulation of microplastics in our environment is a growing concern. These tiny particles have been found to harm marine life, contaminate food chains, and even enter our own bodies through various pathways. However, predicting where these particles will accumulate and therefore where remediation efforts should focus has been difficult due to the many factors contributing to their dispersal and deposition.

New research from MIT shows that one key factor in determining where microparticles are likely to build up is related to the presence of biofilms. These thin, sticky biopolymer layers are shed by microorganisms and can accumulate on surfaces, including riverbeds or seashores. The study found that when these particles land on sediment infused with biofilms, they are more likely to be resuspended by flowing water and carried away.

The research involved a flow tank with a bottom lined with fine sand, sometimes mixed with biological material simulating natural biofilms. Water mixed with tiny plastic particles was pumped through the tank for three hours, and then the bed surface was photographed under ultraviolet light that caused the plastic particles to fluoresce, allowing a quantitative measurement of their concentration.

The results revealed two different phenomena affecting how much plastic accumulated on the different surfaces. Immediately around the rods simulating above-ground roots, turbulence prevented particle deposition. Additionally, as the amount of simulated biofilms in the sediment bed increased, the accumulation of particles also decreased.

The researchers concluded that the biofilms filled up the spaces between the sand grains, leaving less room for the microparticles to fit in. The particles were more exposed because they penetrated less deeply into the sand grains, making them easier to resuspend and carry away by the flowing water.

This research provides a “nice lens” to offer guidance on where to find microplastic hotspots versus not-so-hot areas. For example, in mangrove ecosystems, microplastics may accumulate preferentially in the outer edges, which tend to be sandy, while the interior zones have sediment with more biofilm. This suggests that the sandy outer regions may be potential hotspots for microplastic accumulation.

The work was supported by Shell International Exploration and Production through the MIT Energy Initiative. While other factors like turbulence or roughness of the bottom surface complicate this, it provides a framework to categorize habitats and prioritize monitoring and protection efforts.