Physical and biogeochemical drivers of solute mobilization and flux through the critical zone after wildfire
A nine-year time series of nutrient cation and anion concentration and efflux from three forested catchments in the Jemez River Basin Critical Zone Observatory (JRB-CZO) in northern New Mexico was used to quantify the pulse of chemical denudation resulting from varying levels stand-replacing wildfir...
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| Language: | English |
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Frontiers Media S.A.
2023-05-01
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| Series: | Frontiers in Water |
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| Online Access: | https://www.frontiersin.org/articles/10.3389/frwa.2023.1148298/full |
| _version_ | 1797835594936614912 |
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| author | Rodrigo Andrés Sánchez Rodrigo Andrés Sánchez Thomas Meixner Tirthankar Roy Paul Ty Ferré Martha Whitaker Jon Chorover |
| author_facet | Rodrigo Andrés Sánchez Rodrigo Andrés Sánchez Thomas Meixner Tirthankar Roy Paul Ty Ferré Martha Whitaker Jon Chorover |
| author_sort | Rodrigo Andrés Sánchez |
| collection | DOAJ |
| description | A nine-year time series of nutrient cation and anion concentration and efflux from three forested catchments in the Jemez River Basin Critical Zone Observatory (JRB-CZO) in northern New Mexico was used to quantify the pulse of chemical denudation resulting from varying levels stand-replacing wildfire intensity in May-June of 2013. The 3 years of pre-fire and 6 years of postfire data were also probed to shed light on the mechanisms underlying the pulsed release and the subsequent recovery. The initial large solute pulse released to the streams—K+, Ca2+, Mg2+, SO42-, Cl−, dissolved inorganic carbon (DIC), dissolved organic carbon (DOC), and total dissolved nitrogen (TDN)—was caused by leaching of hillslope ash deposits during the first monsoon storms post-fire. Debris flow following the wildfire likely redistributed much of the ash-containing sediments along streams and valley bottoms. Sustained elevated solute concentrations observed in the surface waters throughout the post-fire period relative to pre-fire baselines is consistent with these soluble materials being periodically flushed from the soils during wet seasons, i.e., snowmelt and summer monsoons. As microbial mediated reactions and biotic uptake—due to plant regrowth—recover after fire, nutrient ion export (e.g., NO3-, Cl− and SO42-) steadily decreased toward the end of the post fire period, but remained above pre-fire levels, particularly for NO3- and SO42-. Surface water concentrations of polyvalent cations (e.g., Al and Fe) decreased significantly after the fire. Our observations suggest that changes in organic matter composition after fire (e.g., increased humification index—HIX) and the presence of pyrogenic carbon may not favor organo-metal complexation and transport. Finally, differences in burn severity among the three watersheds presented in this study, provide insights of the relative impact of solute exports and resilience. The catchments that experienced high burn severity exhibited greater solute fluxes than the less severely burn. Moreover, despite these differences, toward the end of the post-fire period these surface waters presented low and similar solute effluxes, indicating system recovery. Nonetheless, magnitudes and rebounds were solute and process specific. The results of this study highlight the importance of surface and near surface physical and biogeochemical processes on the long-lasting geochemical denudation of forested catchments following wildfires of varying intensities. |
| first_indexed | 2024-04-09T14:55:09Z |
| format | Article |
| id | doaj.art-2ec94c7293b740aabf6865ae24fb087a |
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| language | English |
| last_indexed | 2024-04-09T14:55:09Z |
| publishDate | 2023-05-01 |
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| spelling | doaj.art-2ec94c7293b740aabf6865ae24fb087a2023-05-02T05:19:51ZengFrontiers Media S.A.Frontiers in Water2624-93752023-05-01510.3389/frwa.2023.11482981148298Physical and biogeochemical drivers of solute mobilization and flux through the critical zone after wildfireRodrigo Andrés Sánchez0Rodrigo Andrés Sánchez1Thomas Meixner2Tirthankar Roy3Paul Ty Ferré4Martha Whitaker5Jon Chorover6Department of Hydrology and Atmospheric Sciences, University of Arizona, Tucson, AZ, United StatesDornsife Environmental Studies Program, University of Southern California, Los Angeles, CA, United StatesDepartment of Hydrology and Atmospheric Sciences, University of Arizona, Tucson, AZ, United StatesDepartment of Civil and Environmental Engineering, University of Nebraska-Lincoln, Lincoln, NE, United StatesDepartment of Hydrology and Atmospheric Sciences, University of Arizona, Tucson, AZ, United StatesDepartment of Hydrology and Atmospheric Sciences, University of Arizona, Tucson, AZ, United StatesDepartment of Environmental Science, University of Arizona, Tucson, AZ, United StatesA nine-year time series of nutrient cation and anion concentration and efflux from three forested catchments in the Jemez River Basin Critical Zone Observatory (JRB-CZO) in northern New Mexico was used to quantify the pulse of chemical denudation resulting from varying levels stand-replacing wildfire intensity in May-June of 2013. The 3 years of pre-fire and 6 years of postfire data were also probed to shed light on the mechanisms underlying the pulsed release and the subsequent recovery. The initial large solute pulse released to the streams—K+, Ca2+, Mg2+, SO42-, Cl−, dissolved inorganic carbon (DIC), dissolved organic carbon (DOC), and total dissolved nitrogen (TDN)—was caused by leaching of hillslope ash deposits during the first monsoon storms post-fire. Debris flow following the wildfire likely redistributed much of the ash-containing sediments along streams and valley bottoms. Sustained elevated solute concentrations observed in the surface waters throughout the post-fire period relative to pre-fire baselines is consistent with these soluble materials being periodically flushed from the soils during wet seasons, i.e., snowmelt and summer monsoons. As microbial mediated reactions and biotic uptake—due to plant regrowth—recover after fire, nutrient ion export (e.g., NO3-, Cl− and SO42-) steadily decreased toward the end of the post fire period, but remained above pre-fire levels, particularly for NO3- and SO42-. Surface water concentrations of polyvalent cations (e.g., Al and Fe) decreased significantly after the fire. Our observations suggest that changes in organic matter composition after fire (e.g., increased humification index—HIX) and the presence of pyrogenic carbon may not favor organo-metal complexation and transport. Finally, differences in burn severity among the three watersheds presented in this study, provide insights of the relative impact of solute exports and resilience. The catchments that experienced high burn severity exhibited greater solute fluxes than the less severely burn. Moreover, despite these differences, toward the end of the post-fire period these surface waters presented low and similar solute effluxes, indicating system recovery. Nonetheless, magnitudes and rebounds were solute and process specific. The results of this study highlight the importance of surface and near surface physical and biogeochemical processes on the long-lasting geochemical denudation of forested catchments following wildfires of varying intensities.https://www.frontiersin.org/articles/10.3389/frwa.2023.1148298/fullbiogeochemistrywildfirescritical zonesolute mobilizationfire severity |
| spellingShingle | Rodrigo Andrés Sánchez Rodrigo Andrés Sánchez Thomas Meixner Tirthankar Roy Paul Ty Ferré Martha Whitaker Jon Chorover Physical and biogeochemical drivers of solute mobilization and flux through the critical zone after wildfire Frontiers in Water biogeochemistry wildfires critical zone solute mobilization fire severity |
| title | Physical and biogeochemical drivers of solute mobilization and flux through the critical zone after wildfire |
| title_full | Physical and biogeochemical drivers of solute mobilization and flux through the critical zone after wildfire |
| title_fullStr | Physical and biogeochemical drivers of solute mobilization and flux through the critical zone after wildfire |
| title_full_unstemmed | Physical and biogeochemical drivers of solute mobilization and flux through the critical zone after wildfire |
| title_short | Physical and biogeochemical drivers of solute mobilization and flux through the critical zone after wildfire |
| title_sort | physical and biogeochemical drivers of solute mobilization and flux through the critical zone after wildfire |
| topic | biogeochemistry wildfires critical zone solute mobilization fire severity |
| url | https://www.frontiersin.org/articles/10.3389/frwa.2023.1148298/full |
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