Major Projects

Sediment Transport

 

Sediment transport in coastal environment

"Coastal habitats bear the brunt of global environmental change. Rising sea levels, intense shoreline development, and pollution all contribute to worldwide habitat losses on the order of 1% to 7% per year. Cumulatively, nearly half of the world’s wetlands, mangroves, and seagrass habitats have eroded away over the past several decades." We study how sediments move in laboratory flume to help understand how erosions happen in rivers and coastal areas. Our research have been highlighted in EOS Research Spotlight: "New Study Shifts Paradigm of Coastal Sediment Modeling" 

Related Publications

Yang, J. Q., and H. M. Nepf (2019), Water Resour. Res.

Yang, J.Q., and H.M Nepf (2018), Geophys. Res. Lett

Yang, J. Q., C. Hayoon, and H. M. Nepf (2016), Geophys. Res. Lett.

 


 

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4D imaging of carbon in clay helps understand global carbon cycle

Soil absorbs about 20% of anthropogenic CO2 emissions annually, and clay is one of the key carbon-capture materials. Although sorption to clay is widely assumed to strongly retard the microbial decomposition of soil organic matter, enhanced degradation of clay-associated organic carbon has been observed under certain conditions. The conditions in which clay influences microbial decomposition remain uncertain because the mechanisms of clay-organic carbon interactions are not fully understood. To address this question, we developed the first 4D microfluidics-based imaging technology that shows how carbon is sequestrated in soil and how bacteria can access the carbon by producing extra-cellular enzymes. Our research has been highlighted in highlighted in many news media "Carbon-chomping soil bacteria may pose hidden climate risk" and interviewed by The Counter.org: story about soil carbon and climate change

Related publications

Yang, J. Q., X. Zhang, I. C. Bourg, and H. A. Stone (2021), Nat. Comm. 

 

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Bacterial transport in soil 

Here, we demonstrate a previously unreported mechanism of bacterial spreading in unsaturated porous media, which can inform understanding of soil contamination by pathogens, soft rot in plants, and potentially many pulmonary diseases. We discover that surfactant-producing bacteria establish self-generated flows along corners by producing surfactants that change the wettability of the solid surface. The biosurfactant-driven corner flow has an average velocity of millimeters per hour, which is significant in terms of the spread of bacteria (e.g., pathogens) in soil and other unsaturated porous media.

Related publications

Yang, J. Q., et al. (2021), PNAS.


 

Landscape evolution

 

Landscape evolution

We simulate natural deltas and wetlands in Saint Anthony Fall Laboratory (SAFL) and look at how the landscape evolves. More information about the amazing facilities in SAFL can be found here