In-situ observations of an intact natural whale fall in Palmer deep, Western Antarctic Peninsula

Abstract

Whale carcasses on the seafloor support unique, ephemeral communities of organisms, and ‘natural’ whale fall sites are infrequently encountered, especially in polar regions. During a manned submersible dive in early 2017, we discovered the skeleton of an Antarctic minke whale (Balaenoptera bonaerensis) at 963 m in Palmer Deep, in the Western Antarctic Peninsula. The site was filmed in HD for approximately two hours, enabling visual identification of representatives from at least eight phyla, although physical sampling was not possible. The remains appeared to be in the late ‘enrichment–opportunistic’ phase (although some mobile scavengers were still present and some sulfonic activity had already commenced), with polychaetes of the order Aciculata, and family Ampharetidae, plus several amphipod species, most abundant. Novel eusirid amphipod and rhodaliid siphonophore taxa were also present. The observed faunal distribution suggests patterns consistent with reports from other Antarctic whale falls (both experimental and natural). This discovery represents the highest-latitude natural whale fall reported to date.

Whale fall chemosymbiotic communities in a southwest Australian submarine canyon fill a distributional gap

“…This is inferred from the high organic enrichment of the sediments in direct contact, or immediately adjacent, to the skull. In fact, this whale fall promoted the development of sulphate-reducing and methanogenetic bacterial-archaea consortia, which resulted in chemosynthetic habitats similar to cold seeps [12] , [16] , [79] . These habitats are limited in their areal extent, depending also on the size of the decaying carcass and the type and quantity of lipids 9 , but could exceed the area covered by the whale fall (Bull's eye), and the increase in carbon could be up to 3.5% with respect to adjacent sediments 80 .…”