Fatty acid composition of particulate matter and photosynthetic products in subarctic and subtropical pacific

Abstract

The fatty acid composition of lipid materials in particulate matter and photosynthetic products was determined using 13C gas chromatography-mass spectrometry methodology in the subarctic and subtropical Pacific. Polyunsaturated fatty acids (PUFA) were measured as one of the major constituents of particulate and photosynthetically produced lipids in the subarctic Pacific. In the subtropical Pacific, on the other hand, a quite simple fatty acid composition was found, consisting mainly of saturated fatty acids (SFA) and monounsaturated fatty acids (MUFA); the production rate of PUFA could not be determined due to the low concentration in the subtropical area. The relationship between the fatty acid composition of particulate lipids and photosynthetically produced lipids indicated that PUFA observed in particulate lipids were mainly associated with phytoplankton. Non-living lipids, on the other hand, could be mainly constituted by SFA, due to the lability of PUFA to degradation. The difference in the contribution of phytoplankton lipids to particulate lipids is considered as an important factor affecting the difference in the fatty acid composition of particulate lipids between subarctic and subtropical Pacific.