Presenter: Taylor Eddy (USGS)

Description:
For over 5 decades, the USGS has sustained long-term data collection in the San Francisco Bay – Delta (SFB), California, with one goal being to understand phytoplankton bloom dynamics such as timing and conditions that lead to blooms.  In Jim Cloern's 2018 paper "Patterns, pace, and processes of water-quality variability in a long-studied estuary" he analyzed decadal trends of chlorophyll, nutrient, light and suspended particulate matter, here we continue that same analysis over the most recent decade.  Our results reveal a striking change in SFB phytoplankton bloom patterns, beginning in 2009 there was a significant decline in the appearance and magnitude of phytoplankton spring blooms. We present statistical time series analyses and discuss how and where the timing, magnitude, and duration of spring booms and other parameters have shifted in SFB and offer potential causes of these changes.