World-wide whale worms? A new species ofOsedaxfrom the shallow north Atlantic

Abstract

We describe a new species of the remarkable whalebone-eating siboglinid worm genus, Osedax, from a whale carcass in the shallow north Atlantic, west of Sweden. Previously only recorded from deep-sea (1500-3000 m) whale-falls in the northeast Pacific, this is the first species of Osedax known from a shelf-depth whale-fall, and the first from the Atlantic Ocean. The new species, Osedax mucofloris sp. n. is abundant on the bones of an experimentally implanted Minke whale carcass (Balaenoptera acutorostrata) at 125m depth in the shallow North Sea. O. mucofloris can be cultured on bones maintained in aquaria. The presence of O. mucofloris in the shallow North Sea and northeast Pacific suggests global distribution on whale-falls for the Osedax clade. Molecular evidence from mitochondrial cytochrome oxidase 1 (CO1) and 18S rRNA sequences suggests that O. mucofloris has high dispersal rates, and provides support for the idea of whale-falls acting as 'stepping-stones' for the global dispersal of siboglinid annelids over ecological and evolutionary time.

Genomic versatility and functional variation between two dominant heterotrophic symbionts of deep-sea Osedax worms

“…Now, 17 morphologically diverse species are known worldwide from depths ranging from 25 to 3000 meters Rouse et al, 2004;Glover et al, 2005;Fujikura et al, 2006;Braby et al, 2007;Vrijenhoek et al, 2009;Salathé and Vrijenhoek, 2012). Evidence for Osedax borings in fossilized bones suggests that the genus has historically colonized a large portion of the world's oceans (Higgs et al, 2011;Kiel et al, 2011;Higgs et al, 2012).…”

On the role of bone-eating worms in the degradation of marine vertebrate remains

“…In recent years, a series of both serendipitous discoveries and planned experimental manipulations have provided some of the first data on the fate of whale remains in the deep sea (Smith 2006). One of the more remarkable discoveries has been a specialized 'whale-fall' fauna, including organisms such as Osedax, a sessile polychaete worm that is capable of burrowing into whalebones to extract energy through microbial symbioses (Rouse et al 2004;Glover et al 2005). The recent paper in this journal by Jones et al (2008) puts forward the hypothesis that Osedax is not specialist on whalebones, based on the observation of Osedax growing on cow bones suspended above the seafloor of the Monterey Canyon.…”

“…However, the broad biogeographic range of Osedax is similar to that for cold-seep vestimentiferans and shows even greater bathymetric range. Furthermore, the molecular studies of mtCO1 diversity suggest both large global population sizes (Rouse et al 2004), and a high level of haplotype diversity at single sites (Glover et al 2005;Dahlgren et al 2006). The latter point suggests that at any one single location in the ocean, Osedax larvae from more than one population may be available to colonize a whale carcass, should it so appear.…”

Novel observations of Thiobacterium, a sulfur-storing Gammaproteobacterium producing gelatinous mats

“…Whale bones were recovered from the carcass of a female minke whale that was previously implanted at 125 m depth in Kosterfjord, Sweden (58153.1 0 N, 1116.4 0 E; Glover et al, 2005;Dahlgren et al, 2006). Since their recovery, the bones had been maintained at 7-8 1C in aquaria flushed with filtered seawater (Glover et al, 2005). Sampling of a small spherical Thiobacterium mat was achieved by pipetting.…”