TY - JOUR
T1 - Experimentally simulated sea level rise destabilizes carbon-mineral associations in temperate tidal marsh soil
AU - Fettrow, Sean
AU - Vargas, Rodrigo
AU - Seyfferth, Angelia L.
N1 - Publisher Copyright:
© 2023, The Author(s), under exclusive licence to Springer Nature Switzerland AG.
PY - 2023/3
Y1 - 2023/3
N2 - How sea level rise (SLR) alters carbon (C) dynamics in tidal salt marsh soils is unresolved. Changes in hydrodynamics could influence organo-mineral associations, influencing dissolved organic carbon (DOC) fluxes. As SLR increases the duration of inundation, we hypothesize that lateral DOC export will increase due to reductive dissolution of C-bearing iron (Fe) oxides, destabilizing soil C stocks and influencing greenhouse gas emissions. To test this, soil cores (0–8 cm depth) were collected from the high marsh of a temperate salt marsh that currently experiences changes in water level and soil redox oscillation due to spring-neap tides. Mesocosms experimentally simulated SLR by continuously inundating high marsh soils and were compared to mesocosms with Control conditions, where the water level oscillated on a spring-neap cycle. Porewater DOC, lateral DOC, and porewater reduced Fe (Fe2+) concentrations were significantly higher in SLR treatments (1.7 ± 0.5 mM, 0.63 ± 0.14 mM, and 0.15 ± 0.11 mM, respectively) than Control treatments (1.2 ± 0.35 mM, 0.56 ± 0.15 mM, and 0.08 ± 01 mM, respectively Solid phase analysis with Fe extended X-ray absorption fine-structure spectroscopy further revealed that SLR led to > 3 times less Fe oxide-C coprecipitates than Control conditions In addition, the overall global warming potential (GWP) decreased under SLR due to suppressed CO2 emissions. Our data suggest that SLR may increase lateral C export of current C stocks by dissolving C-bearing Fe oxides but decrease the overall GWP from emissions of soil trace gases. These findings have implications for understanding the fate of SOC dynamics under future SLR scenarios.
AB - How sea level rise (SLR) alters carbon (C) dynamics in tidal salt marsh soils is unresolved. Changes in hydrodynamics could influence organo-mineral associations, influencing dissolved organic carbon (DOC) fluxes. As SLR increases the duration of inundation, we hypothesize that lateral DOC export will increase due to reductive dissolution of C-bearing iron (Fe) oxides, destabilizing soil C stocks and influencing greenhouse gas emissions. To test this, soil cores (0–8 cm depth) were collected from the high marsh of a temperate salt marsh that currently experiences changes in water level and soil redox oscillation due to spring-neap tides. Mesocosms experimentally simulated SLR by continuously inundating high marsh soils and were compared to mesocosms with Control conditions, where the water level oscillated on a spring-neap cycle. Porewater DOC, lateral DOC, and porewater reduced Fe (Fe2+) concentrations were significantly higher in SLR treatments (1.7 ± 0.5 mM, 0.63 ± 0.14 mM, and 0.15 ± 0.11 mM, respectively) than Control treatments (1.2 ± 0.35 mM, 0.56 ± 0.15 mM, and 0.08 ± 01 mM, respectively Solid phase analysis with Fe extended X-ray absorption fine-structure spectroscopy further revealed that SLR led to > 3 times less Fe oxide-C coprecipitates than Control conditions In addition, the overall global warming potential (GWP) decreased under SLR due to suppressed CO2 emissions. Our data suggest that SLR may increase lateral C export of current C stocks by dissolving C-bearing Fe oxides but decrease the overall GWP from emissions of soil trace gases. These findings have implications for understanding the fate of SOC dynamics under future SLR scenarios.
KW - Dissolved organic carbon
KW - Greenhouse gas fluxes
KW - Lateral carbon fluxes
KW - Organo-mineral associations
KW - Synchrotron
KW - Vertical carbon fluxes
UR - http://www.scopus.com/inward/record.url?scp=85147690519&partnerID=8YFLogxK
U2 - 10.1007/s10533-023-01024-z
DO - 10.1007/s10533-023-01024-z
M3 - Article
AN - SCOPUS:85147690519
SN - 0168-2563
VL - 163
SP - 103
EP - 120
JO - Biogeochemistry
JF - Biogeochemistry
IS - 2
ER -
