Soil Microbiome
We examine how the stressors during changing climate shape the microbiome in subsurface treatment systems, so that their design can be modified to improve contaminant removal by biodegradation. Stressors include increase in rainfall intensity, flooding, drying, freezing, and wildfire, all of which are projected to be more frequent during climate change.
Deposition of wildfire residues does not elevate the microbial risk in surface waters and subsurface soil.
Wildfire residues could inhibit the growth of pathogen by adsorbing the nutrients and lowering bacterial viability. They are also removed in subsurface soil, thereby lowering any potential of particle-facilitated transport of pathogens into groundwater.
*Valenca, R., Ramnath, K., Dittrich, T.M., Taylor, R. E., and Mohanty, S.K. (2020) Microbial quality of surface water and subsurface soil after wildfire. Water Research. 175, 115672. https://doi.org/10.1016/j.watres.2020.115672 [ pdf ]
Increase in rainfall intensity or infiltration rate decreases denitrification in woodchip biofilters but adding biochar could partially mitigate that issue.
The results show that biochar ability to increase in denitrification in woodchip biofilters are not because of increase in biological activity, but because of increase proximity of bacteria with the hotspots and geochemical modification of porewater.
Berger, A.W., Valenca, R., Miao, Y., Ravi, S., Mahendra, S. and Mohanty, S.K., 2019. Biochar increases nitrate removal capacity of woodchip biofilters during high-intensity rainfall. Water research. 165, 115008. https://doi.org/10.1016/j.watres.2019.115008 [ pdf ]
