Qualitative and quantitative analysis of Baltic phytoplankton pigments

The paper presents the results of research into the pigment composition of seawater samples taken from various depths in the Gulf of Gdansk in April and September 1999. Pigments were separated by RP-HPLC, and identification was confirmed by co-injection with reference standards and on-line diode array spectra. The following groups of pigments were identified: chlorophylls: a, b, c1 + c2; photosynthetic carotenoids (PSC) - peridinin, fucoxanthin, alfa-carotene; photoprotecting carotenoids (PPC) - diadinoxanthin, alloxanthin, zeaxanthin, lutein, neoxanthin, violaxanthin and beta-carotene. Quantitative and qualitative diversity in pigment characteristics were observed in both seasons, though lutein and alfa-carotene were not identified in the September samples. The respective April and September concentrations of the functional groups of pigments were: total chlorophylls content 0.47-104.25 and 0.57-13.66 μg dm–3; PSC 0.07-21.23 and 0.02-1.56 μg dm–3; PPC 0.05-14.08 and 0.04-1.79 μg dm–3. Within the PSC group, peridinin and fucoxanthin were dominant in the April samples, but only fucoxanthin in the September ones. Among the PPCs, diadinoxanthin and alloxanthin were dominant in April, zeaxanthin in September. Photosynthetic and photoprotecting carotenoids display a linear correlation with chlorophyll alfa content in all the samples.