National Research Program | Isotope Tracers Project

Isotope Tracers Project - Online Reports

The Isotope Tracers Project online reports are prepared in order to (1) show "proof of concept" of the usefulness of isotope techniques combined with water chemistry and hydrological modelling in the studied ecosystem, (2) present key findings from ongoing studies, and (3) provide downloadable files including relevant isotope data to for use by others interested in the ecosystem.

Online reports can be published and updated more rapidly than traditional journal articles, and the format encourages collaboration. In most cases, online reports are intended as a precursor to journal articles providing more thorough interpretation.

San Francisco Estuary

Go to SF Estuary Online Report

This report describes findings from several overlapping studies in the Sacramento River and Delta conducted 2009-2011 to evaluate the potential usefulness of stable isotope techniques for testing hypotheses about sources of nutrients and algae, and biogeochemical processes in these ecosystems. One main focus of the studies was to provide an independent test of the hypothesis that NH4 derived from WWTPs was inhibiting phytoplankton uptake of NO3. This goal was accomplished by collecting ~monthly samples from 15-20 sites along transects of the river and delta to assess the temporal and spatial variations in the sources, transport, and sinks of nutrients and organic matter in the Sacramento River and lower Delta – and then analyzing the samples for ammonium, nitrate, particulate organic matter, dissolved organic matter, and water for their stable isotope compositions.

Florida Everglades

Go to Executive Summary (SOFIA)

View poster presentations on the Florida Everglades project:

Mapping Spatial Variability in Marsh Redox Conditions Using Biomass Stable Isotopic Compositions

Tracing Foodweb Relations and Fish Migratory Habits in the Everglades with Stable Isotope Techniques

Lessons from the Everglades: Atypical isotope patterns in a complex ecosystem