1. GIS Mapping

2. GIS Mapping Base maps provide reference for additional data layers
Base maps of either
Orthophotos
Topographic maps
Combination

3. Topographic map as base map
Overlays identify subwatershed boundaries and streams

4. Cottonwood
Orthophoto base map with subwatershed boundaries

5. Southwest
Creeks
Orthophoto base map with watershed & stream overlays

6. Layers Layers exist for: Streams Roads Subwatersheds Soils
Others easily added
Land Use ?

7. Conesus Lake All soils may be differentiated Topo Map with overlays
Subwatersheds
Streams
Soils

8. SandPoint Soils grouped by dominant soil series
Orthophoto base map with soils overlay

9. Future Needs Pretty Maps vs. GIS
Maps with various parameters are easily generated
Is this the best use of GIS capabilities
Use GIS to develop interface with database
Spatial interface for spatial data

10. Example
Screenshot
Database
ArcMap
GUI

11. P Speciation in Sediments

12. P Speciation
Distribution of P among various sediment physicochemical phases.
P associated with sediment solids and pore water
Determined by selective removal of each phase in a sequential extraction procedure

13. Sequential Extractions
Removal of elements associated with discrete phases
Optimized for a specific element of group of elements
Optimization based on chemical reactivity and associations in the sediment
Extractions become “operationally defined” fractions

14. P Chemistry in Sediments
Exists primarily as phosphate in inorganic fractions
H2PO4- or HPO4-2
Forms strong bonds through ligand exchange with oxyhdroxides of Fe, Al and Mn
Organic fractions are more complex and variable

15. P Interactions with Fe oxyhydroxide
Fe-OH
Easily exchangeable outer sphere
complex (hours)
+ H2PO4-
Fe-OH
Specifically adsorbed inner sphere
complex (days)
Fe-OH
+ OH-
Fe-H2PO4
Anion penetration by ligand
exchange (weeks)
Fe-O O P
+ H2O
Fe-O OH

16. Potential P Fractions Labile Pore water and easily exchangeable P
In equilibrium with solid phases
Most reactive, mobile and bioavailable fraction

17. Potential P Fractions Ca associated P Associated with CaCO3 phases
Produces discrete Ca phosphate phases over time
Ca phosphate phases may be directly precipitated
Relatively insoluble, low bioavailability

18. Potential P Fractions Fe & Mn oxyhydroxide associated P
Specifically adsorbed onto oxyhydroxide surfaces, possibly occluded
May form discrete Fe(II) phosphate phases
Relatively insoluble, but subject to changes in redox conditions
Low bioavailability in solid phase

19. Potential P Fractions Al oxyhydroxide associated P
Similar in reactivity to Fe
Not subject to redox remobilization
Prompts use of alum to remediate high P lakes
Low bioavailability in solid phase

20. Potential P Fractions Organic P Complex and variable phases
Dynamic fraction but poorly understood
Fractionation of organic P is possible

21. Sequential Extraction Scheme
Acetic Acid - removes free carbonates
NH4F - removes Al-P
NaOH - removes organic P
HA/HNO3 - reducible amorphous OxHy
HA/HCl - reducible crystalline OxHy
HCl - Ca-P

22. Sequential Extraction Results

23. Sequential Extraction Results

24. Future Work Fractionation of Conesus Lake sediments
Fractionation of agricultural soil samples