Dynamic variability of biogeochemical ratios in the Southern California Current System

Abstract

We use autonomous nitrate (NO3−), oxygen (O2), 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.