Blue-green pigmented symbionts of echiurids from polar marine environments.

: Burrowing echiurid worms from marine sediments including sulfidic habitats of both the Antarctic Ocean and the Norwegian Sea were partly colonized by blue-green prokaryotic symbionts. These resembled free-living Prochlorophytes and contained 2-vinylpheophorbide-a5 as the only pigment being detectable by HPLC. The potential biogeochemical significance of these epizoic symbionts is discussed.