1. Focus on one form of “deep C” Podzolization - pedogenic translocation & joint accumulation of C & metals: –Eluviation – loss –Illuviation – gain Podzolization => subsurface C sequestration A E Bh SHWT

2. Other pertinent terms Spodic* horizon – meets threshold podzolic C & metal accumulation Spodosol – soil order with Spodic horizon within 2-m depth * Most Bh horizons in Florida meet Spodic criteria

3. Spodosol distribution worldwide Commonly well drained Mainly restricted to imperfectly-drained sites What is the role of the water table in fostering Spodosol formation in Florida? Randy Schaetzl

4. Dupont heavy mineral mine exposure – NE Florida A huge C pool >2m Estimated 431 Tg C in Florida Bh horizons within 2 m Deep, thick C pool mass not estimated Potential C gain or loss tied to climate and sea level How does this C accumulate? Earl Stone, Randy Brown, Ron Kuehl

5. Chelate-complex theory Ex - Low molecular weight Ex – Fulvic acid Ex – Humic acid Al & Fe

6. Negatively-charged OM “Clouds” of hydrated counterions Dispersion Flocculation & immobilization E Bh Complexation & mobilization

7. Line of Scrimmage Soil Surface Buchholtz Eastside Gainesville P.K. Young Oak Hall C Al Theory – Gainesville style

8. Line of Scrimmage Soil Surface C Al

9. Line of Scrimmage Soil Surface C Al

10. Line of Scrimmage Soil Surface C & Al Al

11. Line of Scrimmage Soil Surface C & Al Al Uuughh!

12. Soil Surface E A Bh … and so it is with Spodosols … - but clay moves too, not just metals? C & Al Al & C Keith Hollien, Soil Survey Data

13. “Sandhills” – deep water table “Flatwoods” – shallow water table Coated sand Clean sand

14. Coatings About 2-8 % of soil mass Similar proportions of silt & clay Silt – mostly quartz Clay – quartz, phyllosilicates, gibbsite, & oxides of Al & Fe NOT predominantly “iron oxide coatings”, although … Al- & Fe oxides serve as “cement” Characteristics of Sand Grain Coatings Shannon Chesser, Vic Carlisle