Low temporal variation in the intact polar lipid composition of North Sea coastal marine water reveals limited chemotaxonomic value

[摘要] Temporal variations in the abundance and composition of intact polar lipids(IPLs) in North Sea coastal marine water were assessed over a one-yearseasonal cycle, and compared with environmental parameters and the microbialcommunity composition. Sulfoquinovosyldiacylglycerol (SQDG) was the mostabundant IPL class, followed by phosphatidylcholine (PC),phosphatidylglycerol (PG) and diacylglyceryl-(N,N,N)-trimethylhomoserine (DGTS)in roughly equal concentrations, and smaller amounts ofphosphatidylethanolamine (PE). Although the total concentrations of theseIPL classes varied substantially throughout the year, the composition of theIPL pool remained remarkably constant. Statistical analysis yielded negativecorrelations between IPL concentrations and dissolved inorganic nutrientconcentrations, but no changes in the overall planktonic IPL composition dueto nutrient limitation were observed. Significant correlations between SQDG,PC, PG and DGTS concentrations and chlorophyll a concentrations and algalabundances indicated that eukaryotic primary producers, in particularPhaeocystis globosa, were the predominant source of IPLs at this site. However, while IPLconcentrations in the water were closely tied to total algal abundances, therapid succession of different algal groups blooming throughout the yearresulted in only minor shifts in the IPL composition. Principal componentanalysis showed that the IPLs were derived from multiple sources, and thatno IPL species could be exclusively assigned to a particular algal taxa or(cyano)bacteria. Thus, the most commonly occurring IPLs appear to havelimited chemotaxonomic potential, highlighting the need to use targetedassays of more specific biomarker IPLs.

[学科分类] 地球化学与岩石