Size fractionation of total Chl a larger and smaller than 8 μm data generated by Mike Mullin of the Marine Life Research Group, aboard CalCOFI (California Cooperative Oceanic Fisheries Investigations) cruises of the coast of California, January 1994 - October 1996

CalCOFI Size-Fractionated Chlorophyll a (>8µm / <8µm) contains depth-integrated chlorophyll a biomass split by cell size (larger and smaller than 8 μm), along with zooplankton displacement volume and nitracline depth, generated by Michael Mullin, Director of the Marine Life Research Group (UC San Diego), from samples collected aboard California Cooperative Oceanic Fisheries Investigations (CalCOFI) cruises off the coast of California. The dataset covers twelve quarterly CalCOFI cruises and spans January 1994 to October 1996. At roughly half the stations sampled on each cruise, water was collected at multiple depths using closing bottles on a CTD rosette; chlorophyll from each bottle was retained on a GF/F glass-fiber filter and measured fluorometrically, while an additional combined sample from the shallowest ten bottles (surface to about 100 m) was filtered through an 8 μm membrane filter to isolate the larger size fraction. Total and ≥8 μm chlorophyll were each integrated to 100 m depth, and chlorophyll <8 μm was calculated as the difference between the two. This dataset supports research relating phytoplankton size structure to nitracline depth and zooplankton grazing pressure, for researchers studying controls on phytoplankton community size composition in the California Current.