Correlation of carbon and nitrogen stable isotope ratios in sedimentary organic matter 1

Samples of organic matter separated from nearshore sediments of the Northeast Pacific are characterized by a linear correlation between 13C:12C versus 15N:14N. This correlation appears to represent the mixing of marine and terrestrial “end members” of refractory organic matter. Exceptions to the linear plot include organic matter from riverbeds draining agricultural areas, eutrophic lakes or lagoons with large algal populations, and some other exotic environments.