Letter: N-15 isotopes


Your graphic about the Klamath was very informative (“What would a healthy Klamath River look like?” December 2021). I would like to point out a misconception regarding the N-15 isotope. The different isotopes of nitrogen do not have any impact on healthy forest growth; all isotopes of nitrogen can be used for growth. The N-15 isotope can be used to determine the amount of nitrogen that comes from marine sources, where it is plentiful, versus land sources where it is not found in high abundance. A forest with increased levels of N-15 indicates the possibility that much of the nitrogen is being transported into the forest from a marine source. This can be a bit confusing, and I would hate to see readers think that they need to increase the amount of N-15 in their diets to have proper growth.

Scott R. Lefler, Ph.D.
School of Molecular Sciences
Arizona State University
Tempe, Arizona

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