Size fractionation for total Chl a within the surface layer and calculated size distribution of total Chl a from discrete bottle samples from CCE-CalCOFI Augmented Cruises in the California Current System, 2004 - 2017 (ongoing).

Water for size fractionation of chlorophyll a is sampled from ~10m depth (surface layer) on Line 83 and 87, with scattered inshore stations within the CalCOFI and SCCOOS stations located in the CCE study area. The size distribution of total chlorophyll a is determined by filtering water though filters of differing pore sizes. These are then extracted in acetone and analyzed fluorometrically with Turner Designs 10-AU Fluorometer on CalCOFI cruises (since 2006, ongoing). Chlorophyll a and taxon-specific pigments (chlorophylls and carotenoids) are qualitatively and quantitatively characterized in the lab onshore by several size fractions (< 1µm to > 20µm) utilizing High Performance Liquid Chromatography (HPLC) analysis. The samples analyzed within the CCE region are used to develop a metric for phytoplankton community structure that can be used to monitor its state and changes thereof over time.