Antarctic Seabed Assemblages in an Ice-Shelf-Adjacent Polynya, Western Weddell Sea

• Published in: Biology
• Main Authors: Frinault, Bétina A.V., Christie, Frazer D.W., Fawcett, Sarah E., Flynn, Raquel F., Hutchinson, Katherine A., Montes Strevens, Chloë M. J., Taylor, Michelle L., Woodall, Lucy C., Barnes, David K.A.
• Format: Article in Journal/Newspaper
• Language: English
• Published: MDPI 2022
• Subjects: Antarctic; The Antarctic; Weddell Sea; Weddell; Antarc*; Ice Shelf; Ice Shelves
• Online Access: http://nora.nerc.ac.uk/id/eprint/533638/; https://nora.nerc.ac.uk/id/eprint/533638/1/biology-11-01705-v2.pdf; https://www.mdpi.com/2079-7737/11/12/1705

Ice shelves cover ~1.6 million km2 of the Antarctic continental shelf and are sensitive indicators of climate change. With ice-shelf retreat, aphotic marine environments transform into new open-water spaces of photo-induced primary production and associated organic matter export to the benthos. Predicting how Antarctic seafloor assemblages may develop following ice-shelf loss requires knowledge of assemblages bordering the ice-shelf margins, which are relatively undocumented. This study investigated seafloor assemblages, by taxa and functional groups, in a coastal polynya adjacent to the Larsen C Ice Shelf front, western Weddell Sea. The study area is rarely accessed, at the frontline of climate change, and located within a CCAMLR-proposed international marine protected area. Four sites, ~1 to 16 km from the ice-shelf front, were explored for megabenthic assemblages, and potential environmental drivers of assemblage structures were assessed. Faunal density increased with distance from the ice shelf, with epifaunal deposit-feeders a surrogate for overall density trends. Faunal richness did not exhibit a significant pattern with distance from the ice shelf and was most variable at sites closest to the ice-shelf front. Faunal assemblages significantly differed in composition among sites, and those nearest to the ice shelf were the most dissimilar; however, ice-shelf proximity did not emerge as a significant driver of assemblage structure. Overall, the study found a biologically-diverse and complex seafloor environment close to an ice-shelf front and provides ecological baselines for monitoring benthic ecosystem responses to environmental change, supporting marine management.