Fig. 3.

Particulate and cellular DA concentrations in deck-board batch cultures containing P. turgidula. Basal growth media for the batch cultures was OSP seawater collected using trace metal–clean techniques. Treatments were: no metal amendments (control), amended with iron (1 nM Fe), or amended with iron and copper (1 nM Fe + 10 nM Cu). Particulate DA and Pseudonitzschia abundances were determined after 6 d of incubation when cells were in the stationary phase of growth. Open and solid bars are particulate DA (pDA) and cellular DA (pDA normalized to Pseudonitzschia cell abundance) concentrations, respectively. The volume adjusted MDL for analysis of pDA is 66 pg L⁻¹.