This presentation was prepared for the annual workshop of the Marine Waters workgroup of the Puget Sound Environmental Monitoring Program.  The workshop convenes contributors to the Puget Sound Marine Waters Overview, an annual publication that provides a collective view of Puget Sound marine water quality and conditions, and associated biota from monitoring and observing programs.

The 2018 chlorophyll and phytoplankton data from King County’s long term marine monitoring program reveal a substantial decrease in overall chlorophyll and phytoplankton biovolumes for the Puget Sound Central Basin relative to previous years.  Chlorophyll data suggest a decadal pattern for inter-annual differences in concentrations. Chlorophyll and phytoplankton data (based on 5 years of particle imaging via FlowCAM) indicate an unusually late onset of the 2018 spring bloom.  Growth peaked in May and was generally low throughout the summer.  This resulted in a much lower contribution of the typically dominant genus Chaetoceros to the overall phytoplankton biomass in 2018.