Phosphorus dynamics across a 450 ka vertical chronosequence of loess derived (paleo)soils in central US

Research output: Contribution to journalArticlepeer-review

Abstract

Pedogenesis entails profound changes in terrestrial phosphorus (P) dynamics, yet means to understand how time- and climate-induced soil weathering impacts P-cycling over geologic timescales remain relatively limited to space-for-time substitution approaches with multi-site chronosequences. We tested an alternative approach for evaluating terrestrial P dynamics described by the Walker-Syers model by measuring P pools in a ~ 450 ka loess–paleosol sequence. This vertical chronosequence reflects episodic proglacial loess deposition during multiple glaciations and interglacial soil development in central North America in a four-stage loess–paleosol sequence that initiated with the pre-Illinois Episode glaciation. Changes in P pools estimated by sequential fractionation aligned with the Walker-Syers P model for interglacial periods but not glacial periods, possibly reflecting limited soil weathering in cooler and drier conditions of the latter. Total P decreased from 797 to 328 mg/kg with depth and was higher in paleosols than underlying loess parent materials. During glacial periods, primary P increased due to loess deposition and decreased during interglacial periods concomitantly with increased non-occluded and occluded secondary P pools, the extent of which reflected differences in weathering environments of paleoclimatic conditions and loess accumulation rates. That P fractions reflected the Walker-Syers model demonstrates that single-site vertical chronosequences have potential for evaluating long-term soil P dynamics.

Original languageEnglish (US)
Article number176403
JournalScience of the Total Environment
Volume954
DOIs
StatePublished - Dec 1 2024

Keywords

  • Glacial-interglacial cycles
  • Loess–paleosol sequence
  • Paleoclimate
  • Phosphorus fraction
  • Sequential extraction
  • Vertical chronosequence

ASJC Scopus subject areas

  • Environmental Engineering
  • Environmental Chemistry
  • Waste Management and Disposal
  • Pollution

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