UC San Diego

We use autonomous nitrate (NO3-), oxygen (O 2), and dissolved inorganic carbon (DIC) observations to examine the relationship between ratios of C:N:O at an upwelling site in the Southern California Current System. Mean ratios and 95% confidence intervals observed by sensors over 8 months were NO3-:O2-=0.11- ±-0.002, NO3-:DIC-=-0.14-±-0.001, and DIC:O2-=0.83-±-0.01, in good agreement with Redfield ratios. Variability in the ratios on the weekly time scale is attributable to shifts in biological demand and nutrient availability and shown to exhibit a spectrum of values ranging from near 100% New Production to 100% Regenerated Production. Key Points Chemical sensors provide a means to observe the Redfield ratios Redfield ratios vary on the weekly timescale The f ratio ranges from 100% New to 100% Regenerated Production © 2014. American Geophysical Union. All Rights Reserved.