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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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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 • 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
Human Domination of the Global N Cycle Credits: Netherlands Environmental Assessment Agency, www.pbl.nl
Nitrogen Saturation: Environmental Consequences Credits: Diaz and Rosenberg, Science, 2008
Nitrogen Saturation: Symptoms and Diagnosis Credits: Aber, BioScience, 1998
What about organic nitrogen? Credits: Bormann et al., Science, 1977
What about organic nitrogen? Organic N turnover supports the majority of ecosystem production in most ecosystems Credits: Bormann et al., Science, 1977
DON Losses from the landscape are important Credits: Scott et al., Global BGC Cycles, 2007
Nitrogen Saturation: Symptoms and Diagnosis DON?? Credits: Aber, BioScience, 1998
‘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
DON Release Hypothesis: Predictions [DON] DON [DIN]
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
DON Release Hypothesis: Preliminary Test Bioavailability Assays +C +N +CN +DI
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
Ecosystem Scale Experimental Manipulations NUTRIENT SPIRALING THEORY
Ecosystem Scale Experimental Manipulations NUTRIENT SPIRALING THEORY Pump Metering in C/N
Ecosystem Scale Experimental Manipulations Day 2: C Enrichment Day 1: N Enrichment
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
Large differences in DOM stoichiometry with different parent geology
Batch incubation soil sorption assays Unprocessed Soil Removal of Fe/Al Removal of Native Organic Matter Artificial Leachates
Batch incubation soil sorption assays Credits: Qualls, Forest Ecol. & Managmnt, 2001
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
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
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
Acknowledgments • Host: • Rolf Vogt • UiO Chemistry Department • Funding: • Research Council of Norway • National Science Foundation
Implications for Ecosystem N Losses Credits: Schimel and Bennett, Ecology, 2004