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Brian Lutz PhD Candidate, Duke University Visiting Researcher, University of Oslo

Investigating interactions between the major biogeochemical cycles through understanding ecosystem-scale organic matter dynamics. Brian Lutz PhD Candidate, Duke University Visiting Researcher, University of Oslo. Outline. Research Background and Justification

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Brian Lutz PhD Candidate, Duke University Visiting Researcher, University of Oslo

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  1. Investigating interactions between the major biogeochemical cycles through understanding ecosystem-scale organic matter dynamics Brian Lutz PhD Candidate, Duke University Visiting Researcher, University of Oslo

  2. Outline • Research Background and Justification • Ch 1: Preliminary Test of Hypotheses • Synoptic Surveys of Stream Chemistry • Ch 2: Ecosystem Scale Manipulations • Stream Nutrient Spiraling • Ch 3: Geochemical Controls on DON Losses • Soil Sorption Assays • Ch 4: DOM Characterization • Fluorescence and PARAFAC Modeling • Eutropia Project

  3. Human Domination of the Global N Cycle Credits: Netherlands Environmental Assessment Agency, www.pbl.nl

  4. Nitrogen Saturation: Environmental Consequences Credits: Diaz and Rosenberg, Science, 2008

  5. Nitrogen Saturation: Symptoms and Diagnosis Credits: Aber, BioScience, 1998

  6. What about organic nitrogen? Credits: Bormann et al., Science, 1977

  7. What about organic nitrogen? Organic N turnover supports the majority of ecosystem production in most ecosystems Credits: Bormann et al., Science, 1977

  8. DON Losses from the landscape are important Credits: Scott et al., Global BGC Cycles, 2007

  9. Nitrogen Saturation: Symptoms and Diagnosis DON?? Credits: Aber, BioScience, 1998

  10. ‘Breaks in the Cycle’: Increased organic N losses? - Neff et al., Frontiers in Ecology, 2003 Saturated Plant Demand Anthropogenic N Additions INCREASED ORGANIC N LOSSES

  11. DON Release Hypothesis: Schematic

  12. DON Release Hypothesis: Predictions [DON] DON [DIN]

  13. Outline • Research Background and Justification • Ch 1: Preliminary Test of Hypotheses • Synoptic Surveys of Stream Chemistry • Ch 2: Ecosystem Scale Manipulations • Stream Nutrient Spiraling • Ch 3: Geochemical Controls on DON Losses • Soil Sorption Assays • Ch 4: DOM Characterization • Fluorescence and PARAFAC Modeling • Eutropia Project

  14. DON Release Hypothesis: Preliminary Test

  15. DON Release Hypothesis: Preliminary Test

  16. DON Release Hypothesis: Preliminary Test

  17. DON Release Hypothesis: Preliminary Test

  18. DON Release Hypothesis: Preliminary Test

  19. DON Release Hypothesis: Preliminary Test Bioavailability Assays +C +N +CN +DI

  20. Indirect Carbon Control Hypothesis

  21. Outline • Research Background and Justification • Ch 1: Preliminary Test of Hypotheses • Synoptic Surveys of Stream Chemistry • Ch 2: Ecosystem Scale C/N Manipulations • Stream Nutrient Spiraling • Ch 3: Geochemical Controls on DON Losses • Soil Sorption Assays • Ch 4: DOM Characterization • Fluorescence and PARAFAC Modeling • Eutropia Project

  22. Ecosystem Scale Experimental Manipulations NUTRIENT SPIRALING THEORY

  23. Ecosystem Scale Experimental Manipulations NUTRIENT SPIRALING THEORY Pump Metering in C/N

  24. Ecosystem Scale Experimental Manipulations Day 2: C Enrichment Day 1: N Enrichment

  25. Outline • Research Background and Justification • Ch 1: Preliminary Test of Hypotheses • Synoptic Surveys of Stream Chemistry • Ch 2: Ecosystem Scale Manipulations • Stream Nutrient Spiraling • Ch 3: Geochemical Controls on DON Losses • Soil Sorption Assays • Ch 4: DOM Characterization • Fluorescence and PARAFAC Modeling • Eutropia Project

  26. The Importance of Geochemical Controls

  27. Large differences in DOM stoichiometry with different parent geology

  28. Batch incubation soil sorption assays Unprocessed Soil Removal of Fe/Al Removal of Native Organic Matter Artificial Leachates

  29. Batch incubation soil sorption assays Credits: Qualls, Forest Ecol. & Managmnt, 2001

  30. Outline • Research Background and Justification • Ch 1: Preliminary Test of Hypotheses • Synoptic Surveys of Stream Chemistry • Ch 2: Ecosystem Scale Manipulations • Stream Nutrient Spiraling • Ch 3: Geochemical Controls on DON Losses • Soil Sorption Assays • Ch 4: DOM Characterization • Fluorescence and PARAFAC Modeling • Eutropia Project

  31. DOM Characterization: Fluorescence and PARAFAC

  32. Outline • Research Background and Justification • Ch 1: Preliminary Test of Hypotheses • Synoptic Surveys of Stream Chemistry • Ch 2: Ecosystem Scale Manipulations • Stream Nutrient Spiraling • Ch 3: Geochemical Controls on DON Losses • Soil Sorption Assays • Ch 4: DOM Characterization • Fluorescence and PARAFAC Modeling • Eutropia Project

  33. What am I doing in Norway? • Working with Eutropia Project • Flux of Organic N and P from catchment soils to stream • Event (storm) export of OM from catchments • End Member Mixing Models (EMMA) X Y Z

  34. Acknowledgments • Host: • Rolf Vogt • UiO Chemistry Department • Funding: • Research Council of Norway • National Science Foundation

  35. Implications for Ecosystem N Losses Credits: Schimel and Bennett, Ecology, 2004

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