Mixing of Nitrogen Isotopes

Measurements of Nitrogen isotopic compositions of stream reaches supplemented by salmon carcasses and reaches without supplementation show a pattern consistent with mixing of marine and terrestrial nitrogen.
This is not the same as demonstrating that salmon account for a net addition of nutrients to the freshwater system.

this observation has been used as confirmation of the importance of the upstream transport of nutrients by salmon

Measurements of Nitrogen isotopic compositions of stream reaches supplemented by salmon carcasses and reaches without supplementation show a pattern consistent with mixing of marine and terrestrial nitrogen.