Details
| Original language | English |
|---|---|
| Pages (from-to) | 133 - 151 |
| Number of pages | 19 |
| Journal | Quaternary research |
| Volume | 130 |
| Early online date | 8 Oct 2025 |
| Publication status | Published - Mar 2026 |
Abstract
Rhizoliths, cylindrical concretions formed primarily by CaCO3 accumulation around plant roots, serve as valuable indicators of past environmental conditions, including hydrology, redox dynamics, and carbon cycling. Despite growing interest in paleo-reconstructions, the lack of quantitative studies on formation mechanisms complicates interpretation. We present "RhizoCalc", the first mechanistic model (deployed in HYDRUS-1D) computing rhizolith formation in CaCO3-containing loess soils, integrating water fluxes, root water uptake, and (Ca)-carbonate chemistry to simulate conditions under which rhizoliths develop. Hydraulic fluxes drive Ca2+ transport (0.13-1 mmol/L) toward the rhizosphere, governed by root water uptake under low (ETo = 0.03 cm/d) and high (ETo = 1 cm/d) flow rates at optimal (ho = -100 cm) and intermediate (ho = -1000 cm) moisture conditions. The simulations show that hydraulic constraints and calcite-induced jamming of the porous medium are key inhibitors of rhizolith growth, distinguishing physical limitations from biogeochemical feedbacks in the rhizosphere. On top of this, our work reveals root encasement and reliquary varieties, linking their physical and biogeochemical mechanisms to rhizolith transformations and offering insights into paleosol hydrology and redox dynamics. Under intermediate soil-water conditions with 1 mmol/L Ca2+, concentric rhizoliths with 0.2-3 cm radii form chrono-sequentially over 1.5-150 years. Each layer preserves CaCO3 constituents (18O, 13C, 44Ca, 46Ca, 48Ca), root-derived biomarkers (e.g., lignin), and clumped isotopes (47), preserving environmental signatures across time into the future. Therefore, this framework conceptualizes each rhizolith as a 'time-capsule' with each successive CaCO3 layer encapsulating a snapshot of vital environmental proxies, providing a window into otherwise inaccessible historic ecosystem dynamics. Refining reconstructions of Earth's paleoclimatic history requires cross-sectional isolation of concentric layers in well-preserved rhizoliths, capturing distinct isotopic bands and their stratigraphy.
Keywords
- HYDRUS-1D, Rhizolith formation mechanisms, calcium carbonate-containing soils, evapotranspiration rates, hydraulic redistribution, paleoenvironmental reconstructions, pedogenic processes, root water uptake, soil-water dynamics, time capsule
ASJC Scopus subject areas
- Arts and Humanities(all)
- Arts and Humanities (miscellaneous)
- Earth and Planetary Sciences(all)
- Earth-Surface Processes
- Earth and Planetary Sciences(all)
- General Earth and Planetary Sciences
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In: Quaternary research, Vol. 130, 03.2026, p. 133 - 151.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Mechanistic models for rhizolith formation and their implications for paleoenvironmental reconstructions
AU - Tetteh, Kenneth
AU - Sun, Qingfeng
AU - Guggenberger, Georg
AU - Kuzyakov, Yakov
AU - Cornelis, Wim
AU - Zamanian, Kazem
N1 - Publisher Copyright: © The Author(s), 2025.
PY - 2026/3
Y1 - 2026/3
N2 - Rhizoliths, cylindrical concretions formed primarily by CaCO3 accumulation around plant roots, serve as valuable indicators of past environmental conditions, including hydrology, redox dynamics, and carbon cycling. Despite growing interest in paleo-reconstructions, the lack of quantitative studies on formation mechanisms complicates interpretation. We present "RhizoCalc", the first mechanistic model (deployed in HYDRUS-1D) computing rhizolith formation in CaCO3-containing loess soils, integrating water fluxes, root water uptake, and (Ca)-carbonate chemistry to simulate conditions under which rhizoliths develop. Hydraulic fluxes drive Ca2+ transport (0.13-1 mmol/L) toward the rhizosphere, governed by root water uptake under low (ETo = 0.03 cm/d) and high (ETo = 1 cm/d) flow rates at optimal (ho = -100 cm) and intermediate (ho = -1000 cm) moisture conditions. The simulations show that hydraulic constraints and calcite-induced jamming of the porous medium are key inhibitors of rhizolith growth, distinguishing physical limitations from biogeochemical feedbacks in the rhizosphere. On top of this, our work reveals root encasement and reliquary varieties, linking their physical and biogeochemical mechanisms to rhizolith transformations and offering insights into paleosol hydrology and redox dynamics. Under intermediate soil-water conditions with 1 mmol/L Ca2+, concentric rhizoliths with 0.2-3 cm radii form chrono-sequentially over 1.5-150 years. Each layer preserves CaCO3 constituents (18O, 13C, 44Ca, 46Ca, 48Ca), root-derived biomarkers (e.g., lignin), and clumped isotopes (47), preserving environmental signatures across time into the future. Therefore, this framework conceptualizes each rhizolith as a 'time-capsule' with each successive CaCO3 layer encapsulating a snapshot of vital environmental proxies, providing a window into otherwise inaccessible historic ecosystem dynamics. Refining reconstructions of Earth's paleoclimatic history requires cross-sectional isolation of concentric layers in well-preserved rhizoliths, capturing distinct isotopic bands and their stratigraphy.
AB - Rhizoliths, cylindrical concretions formed primarily by CaCO3 accumulation around plant roots, serve as valuable indicators of past environmental conditions, including hydrology, redox dynamics, and carbon cycling. Despite growing interest in paleo-reconstructions, the lack of quantitative studies on formation mechanisms complicates interpretation. We present "RhizoCalc", the first mechanistic model (deployed in HYDRUS-1D) computing rhizolith formation in CaCO3-containing loess soils, integrating water fluxes, root water uptake, and (Ca)-carbonate chemistry to simulate conditions under which rhizoliths develop. Hydraulic fluxes drive Ca2+ transport (0.13-1 mmol/L) toward the rhizosphere, governed by root water uptake under low (ETo = 0.03 cm/d) and high (ETo = 1 cm/d) flow rates at optimal (ho = -100 cm) and intermediate (ho = -1000 cm) moisture conditions. The simulations show that hydraulic constraints and calcite-induced jamming of the porous medium are key inhibitors of rhizolith growth, distinguishing physical limitations from biogeochemical feedbacks in the rhizosphere. On top of this, our work reveals root encasement and reliquary varieties, linking their physical and biogeochemical mechanisms to rhizolith transformations and offering insights into paleosol hydrology and redox dynamics. Under intermediate soil-water conditions with 1 mmol/L Ca2+, concentric rhizoliths with 0.2-3 cm radii form chrono-sequentially over 1.5-150 years. Each layer preserves CaCO3 constituents (18O, 13C, 44Ca, 46Ca, 48Ca), root-derived biomarkers (e.g., lignin), and clumped isotopes (47), preserving environmental signatures across time into the future. Therefore, this framework conceptualizes each rhizolith as a 'time-capsule' with each successive CaCO3 layer encapsulating a snapshot of vital environmental proxies, providing a window into otherwise inaccessible historic ecosystem dynamics. Refining reconstructions of Earth's paleoclimatic history requires cross-sectional isolation of concentric layers in well-preserved rhizoliths, capturing distinct isotopic bands and their stratigraphy.
KW - HYDRUS-1D
KW - Rhizolith formation mechanisms
KW - calcium carbonate-containing soils
KW - evapotranspiration rates
KW - hydraulic redistribution
KW - paleoenvironmental reconstructions
KW - pedogenic processes
KW - root water uptake
KW - soil-water dynamics
KW - time capsule
UR - http://www.scopus.com/inward/record.url?scp=105018751176&partnerID=8YFLogxK
U2 - 10.1017/qua.2025.10021
DO - 10.1017/qua.2025.10021
M3 - Article
VL - 130
SP - 133
EP - 151
JO - Quaternary research
JF - Quaternary research
SN - 0033-5894
ER -