DECADAL-SCALE SHIFTS IN NORTH ATLANTIC BLOOM TIMING FROM SATELLITE OBSERVATIONS

Abstract

This study examines decade-scale shifts in annual phytoplankton bloom timing across the North Atlantic Ocean. Phytoplankton blooms in this region play a critical role in regulating the global carbon cycle and marine ecosystem dynamics. Decadal shifts in the mean timing of bloom onset, bloom termination and bloom duration were examined using 22 years of satellite-derived ocean color data. At higher latitudes in the North Atlantic, median bloom onset date was shifted 4.4 days later, median bloom termination was shifted 1.5 days earlier and median bloom duration shifted 3.6 days shorter. At lower latitudes in the North Atlantic, median bloom onset date was shifted 2.9 days earlier, there was no observed shift in median bloom termination and median bloom duration was shifted 3.6 days longer. Interdecadal trends in wind speeds in the North Atlantic have been documented in a recent study, offering an explanation for the observed shifts in bloom timing. This study produces a first look into recent decadal shifts in bloom timing that should continue to be monitored and studied as more satellite ocean color data are collected.