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Changes in Phosphorus Fractions During Primary Succession in Lake Michigan Sand Dunes, USA

Changes in Phosphorus Fractions During Primary Succession in Lake Michigan Sand Dunes, USA. Scott Bridgham 1 and E. Ryan Murray, Univ. of Notre Dame, IN USA R. G. (Jerry) Qualls and Julia Lilienfen Univ. of Nevada, Reno, NV USA 1 As of Jan. 1, Univ. of Oregon. g P / unit area profile.

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Changes in Phosphorus Fractions During Primary Succession in Lake Michigan Sand Dunes, USA

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  1. Changes in Phosphorus Fractions During Primary Succession in Lake Michigan Sand Dunes, USA Scott Bridgham1 and E. Ryan Murray, Univ. of Notre Dame, IN USA R. G. (Jerry) Qualls and Julia Lilienfen Univ. of Nevada, Reno, NV USA 1As of Jan. 1, Univ. of Oregon

  2. g P / unit area profile Piapatite Ptotal Pioccluded Pinon-occluded Po Time From Walker and Syers 1976

  3. Modified Hedley Sequential P Fractions Set A Set B Fraction 0.5 g sample 0.5 g sample Anion-Exchange Membrane (Pi) Anion-Exchange Membrane (Pi) Pi = Readily available Po = labile organic 0.5 M NaHCO3 (Pi + Po) Chloroform + 0.5 M NaHCO3 (Pt) Microbial P Pi = Non-occluded + occluded Fe-Al phosphates and sesquioxides Po = stable organic 0.1 M NaOH (Pi + Po) Sonicate + 0.1 M NaOH (Pi + Po) 1 M HCl (Pi) Stable Ca-bound Pi Conc. HCl (Pi + Po) Highly recalcitrant Pi + Po Digest in conc. H2SO4 and 30% H2O2 (Pt) Residual P

  4. ~ 50-year old site

  5. ~50- year old site. No A-horizon, little soil development.

  6. 400-year old site. ~10-cm A horizon, Stained ‘B’ horizon

  7. 900-year old site. ~10-cm A horizon, Stained ‘B’ horizon

  8. 8,000-year old site. ~10-cm A horizon, Stained ‘B’ horizon

  9. 12,000-year old site. ~10-cm A horizon, Stained ‘B’ horizon

  10. Conclusions • As opposed to classic ecosystem successional theory, total P increases over time in Lake Michigan sand dunes due to very low initial concentrations. • Changes in individual P fractions as a percentage of the total P more closely follow classical theory.

  11. % total Pi decreases with age and increases with depth. The opposite trends occur for %total Po. • % readily available Piincreases with age. • % Fe and Al-associated Pi increase with age. • Ca-associated Pi decreases with age.

  12. Both recalcitrant and available Po fractions increase with time, with the majority of Po in recalcitrant fractions. • While this study and others have demonstrated the general applicability of classical successional theory for soil P retention, differences in initial soil substrata can lead to important differences in the trajectories of both total P and the individual P fractions.

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