Divinyl chlorophyll a in the marine eukaryotic protist Alexandrium ostenfeldii (Dinophyceae)

Here it is reported the first detection of DV‐chl a together with the usual chl a in the marine dinoflagellate Alexandrium ostenfeldii from the Baltic Sea. Growth response and photosynthetic parameters were examined at two irradiances (80 and 240 μmol photons m⁻² s⁻¹) and temperatures (15°C and 19°C) in a divinylic strain (AOTV‐OS20) versus a monovinylic one (AOTV‐OS16), using in vivo chl a fluorescence kinetics of PSII to characterize photosynthetic parameters by pulse amplitude modulated fluorescence, ¹⁴C assimilation rates and toxin analyses. The divinylic isolate exhibited slower growth and stronger sensitivity to high irradiance than normal chl a strain. DV‐chl a : chl a ratios decreased along time (from 11.3 to