Multiscalarity of the Nutrient–Chlorophyll Relationship in Coastal Phytoplankton

Abstract

The relationship between nitrogen (N) and phytoplankton chlorophyll a (Chl) establishes a basis for understanding eutrophication in coastal marine ecosystems. A substantial literature exists on cross-ecosystem analysis of this relationship, but there is little information on cross-scale patterns. A collection of observational records in Bedford Basin (Canada) was used to construct the N–Chl relationship at four time scales: intra-day, intra-annual, interannual, and interdecadal. Additionally, a dataset of contingent observations from 16 biogeochemical ocean provinces was used to construct the N–Chl relationship at large spatial scale. In Bedford Basin, N statistically predicts Chl at time scales that are short (intra-day, intra-annual) and long (interdecadal) but not intermediate (interannual). There is an apparent stoichiometric regularity in the dependence of Chl on N that crosses time scales. Further, an apparent similitude exists between the local pattern at long time scale and the global pattern at large space scale.