Fig. 1.

Ambient concentrations of particulate DA and size-fractionated phytoplankton biomass as a function of time at OSP in May 2006. Discrete samples were collected using 10-L Niskin bottles; 1-L subsamples were filtered for pDA (•) and analyzed fresh at sea using a cELISA; 0.2-L and 0.4-L subsamples were filtered in parallel for phytoplankton biomass as chlorophyll a on Whatman GF/F filters (nominal pore size, 0.7 μm) for total chlorophyll a (○) and on Poretics 20 μm pore size polycarbonate filters for the >20-μm fraction (□), respectively, and analyzed fluorometrically (33). Values below the volume adjusted MDL of 25.6 pg L⁻¹ (for 1-L samples) are reported with an asterisk.