High prevalence of polyunsaturated-fatty-acid producing bacteria in arctic invertebrates

Bacteria producing the two long-chained polyunsaturated fatty acids eicosapentaenoic (20:5 n–3) and docosahexaenoic (22:6 n–3) acid, which principally have been associated with deep-sea environments, were found in the culturable flora of all species of a selection of 10 arctic and sub-arctic invertebrates and in one of four fish species. In total, 103 out of 330 strains which were tested carried this trait. Highest prevalences, i.e., more than 50% of total isolates were detected in two species of bivalves (Chlamys islandica and Astarte sp.) and in the amphipod Gammarus wilkitzkii. Standard taxonomic tests, supplemented with fatty-acid profile analysis, affiliated all polyunsaturated-fatty-acid producing strains either to the pseudomonad or vibrio main groups of marine bacteria.