Species-specific differences in intact wax esters of Calanus hyperboreus and C. finmarchicus from Fram Strait — Greenland Sea

Abstract

Intact wax esters were studied in the herbivorous calanoid copepods Calanus hyperboreus and C. finmarchicus from the close pack ice region and the marginal ice zone (MIZ) of the Fram Strait in the northern Greenland Sea. Wax esters ranging from 30 to 44 carbon atoms with up to seven double bonds were identified. In the MIZ both species had significantly higher proportions of polyunsaturated wax esters than those in the pack ice zone, as a result of the different nutritional regimes. Despite this spatial variability, pronounced species-specific differences were found. Calanus hyperboreus lipids contained more diunsaturated long-chain wax esters of 38:2, 40:2, 42:2 and 44:2 structure, whereas C. finmarchicus lipids were dominated more by the monounsaturated short-chain wax esters, 34:1 and 36:1. The identification and molecular structure of the wax esters were confirmed by analysing fatty acid and alcohol moieties separately. Only small differences were detected between the wax ester compositions of females and copepodid stages IV and V. There was a tendency towards long-chain wax esters in the older stages.