Publications by authors named "W Kew"
Mineral-associated soil organic matter (SOM) is critical for stabilizing organic carbon and mitigating climate change. However, mineral-SOM interactions at the molecular scale, particularly synergetic adsorption through organic-organic interaction on the mineral surface known as organic multilayering, remain poorly understood. This study investigates the impact of organic multilayering on mineral-SOM interactions, by integrating macroscale experiments and molecular-scale simulations that assess the individual and sequential adsorption of major SOM compounds-lauric acid (lipid), pentaglycine (amino acid), trehalose (carbohydrate), and lignin onto soil minerals.
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- Increasing wildfire severity in the western U.S. affects the production and composition of dissolved organic matter (DOM), which is crucial for understanding its impact on ecosystems.
- Current research on wildfire-affected DOM focuses on temperature, but this doesn't capture the full complexity of post-fire conditions characterized by burn severity.
- This study used simulated burns to analyze DOM from various land cover types, revealing that burn severity alters DOM composition, leading to an increase in aromatic and nitrogen-containing compounds as severity rises, enhancing our understanding of DOM in real-world scenarios.
Wildfires emit solid-state strongly absorptive brown carbon (solid S-BrC, commonly known as tar ball), critical to Earth's radiation budget and climate, but their highly variable light absorption properties are typically not accounted for in climate models. Here, we show that from a Pacific Northwest wildfire, over 90% of particles are solid S-BrC with a mean refractive index of 1.49 + 0.
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- Plant roots and their associated microbes release various exudates that influence soil carbon storage, nutrients, and contaminants.
- A new method using microsensors and mass spectrometry allows for nondestructive measurement of exudation and biogeochemical changes along plant roots over time.
- Findings reveal that exudates create unique soil microenvironments, with specific relationships between sugars and microbial activity, as well as organic acids affecting soil pH as roots grow.
Matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) can provide spatially resolved molecular information about a sample. Recently, a postionization approach (MALDI-2) has been commercially integrated with MALDI-MSI, allowing for bettered sensitivity and consequent improved spatial resolution. While advantages of MALDI-2 have previously been established, we demonstrate here statistically increased in-source fragmentation (ISF) results from postionization with a commercial instrument.
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