Drivers of phytoplankton blooms in Hawaii: A regional model study

Here, we use a coupled physical-biogeochemical model of the MHI to elucidate some of the different dynamics behind phytoplankton blooms. The model permits submesoscale processes and is integrated for the years 2010-2017 embedded in a physical state-estimate reanalysis using nearly 50 million observations.

Model results exhibit good agreement between simulated values and observations at Station ALOHA for physical and biogeochemical parameters. The overall levels and the amplitude of the seasonal cycles are well captured for many variables. We show that variations in net primary production are mainly driven by domain-wide seasonal cycles of light and nitrogen fixers, respectively, as well as short-lived, stochastic bloom events resulting from the formation of eddies to the west of the island of Hawaii.