Unusual fatty acid composition of storage lipids in the bresilioid shrimp Rimicaris exoculata couples the photic zone with MAR hydrothermal vent sites

Lipid and stable carbon isotope analyses of Rimicans exoculata, the dominant breslhoid shrimp found at the MAR (Mid-Atlantic Ridge) vent sites, have indicated that these animals possess a lughly 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 6l3C (V-PDB) values of -17.6 to -27.1 L, which is within the range expected for a photosynthetic origin for these compounds. Fatty acid analyses of bactenddetrital 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 lughly speciaiized iipid metaboiism which allows it to Store substantial amounts of PUFA during its early planktotropluc 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.