NMR Investigations of Natural Organic Matter in Forest Ecosystems Chris E. Johnson Dept. of Civil & Environmental Engineering Syracuse University

Forest Ecosystem Analysis

NMR Applications in Forest Ecosystem Studies 1.Plant tissues: −Wood quality −Response to environmental stress −Litter quality

1.Plant tissues: −Wood quality −Response to environmental stress −Litter quality 2.Soil organic matter: −Decomposition −Accumulation and role as microbial substrate NMR Applications in Forest Ecosystem Studies

1.Plant tissues: −Wood quality −Response to environmental stress −Litter quality 2.Soil organic matter: −Decomposition −Accumulation and role as microbial substrate 3.Aquatic organic matter: −Similarity to soil organic matter −Substrate for aquatic organisms NMR Applications in Forest Ecosystem Studies

Northern Hardwood Forest

Plant Tissues – Wood and Bark

Spectral Integration Alkyl-CO-Alkyl-CAryl C COOH/ Amide O Aryl

Plant Tissues – In situ Decomposition

Sampling with replication Replication is crucial for: Avoiding spurious conclusions Statistical hypothesis testing  (CPMAS method may be the only viable option)

Plant Tissues – (Fresh) Beech Bark

Plant Tissues – Wood & Bark

NMR analysis of soils

Soils – Humification of Organic Matter

Soil vs. Soil Solution SoilsSoil Solutions

Contrasting Soil and Solution Composition: % Aromatic C

Approaches to Quantification 1. Bloch Decay (i.e. Direct Polarization)

Oa Horizon Soil

Approaches to Quantification 2. Spin (Ac)counting

Approaches to Quantification 3. Correction Factors (from VCT Experiments) Oa Horizon Soil

Approaches to Quantification 4. Spectral Editing Approaches a.Proton Spin Relaxation Editing (PSRE) b.RE storation of S pectra via T CH and T O ne R ho (T1  H ) E diting (RESTORE)

Conclusions 1.NMR analyses provide useful information for ecological studies.  An ideal application for low-field instruments. 2.Replication is essential for most ecological applications.  Replication means high sample numbers.  High sample numbers mean CPMAS may be the only viable option. 3.Limited quantitative reliability of the CPMAS method is a problem.  Without reliable approaches to quantification, NMR will remain a supportive technology in ecosystem science