ABSTRACT: Lipid and stable carbon isotope analyses of Rimicaris exoculata, the dominant bresilioid shrimp found at the MAR (Mid-Atlantic Ridge) vent sites, have indicated that these animals possess a highly unusual storage lipid composition. The dominant neutral lipid classes, triacylglycerols and wax esters, contained very high levels of polyunsaturated fatty acids (PUFA, up to 89% of neutral lipid fatty acids). Gas chromatography isotope ratio mass spectrometry (GC-IRMS) analysis of the PUFA from neutral lipid gave d13C (v-PDB) values of -17.6 to -27.1[per thou], which is within the range expected for a photosynthetic origin for these compounds. Fatty acid analyses of bacterial/detrital material collected from the vent sites contained only very low amounts of PUFA. It is clear from these findings that R. exoculata has evolved a highly specialized lipid metabolism which allows it to store substantial amounts of PUFA during its early planktotrophic life stages. These PUFA reserves will be subsequently mobilized to enable growth and maturation of the shrimp on return to a suitable vent site and are therefore an important factor allowing R. exoculata to inhabit deep sea vent ecosystems.

KEY WORDS: Hydrothermal vent shrimp · Nutrition · Lipid metabolism · Wax ester · PUFA

Published in MEPS Vol. 198 (2000) on June 5
ISSN: 0171-8630. Copyright © Inter-Research, Oldendorf/Luhe, 2000