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

• Published in: Biology
• Main Authors: Bétina A. V. Frinault, Frazer D. W. Christie, Sarah E. Fawcett, Raquel F. Flynn, Katherine A. Hutchinson, Chloë M. J. Montes Strevens, Michelle L. Taylor, Lucy C. Woodall, David K. A. Barnes
• Format: Article in Journal/Newspaper
• Language: English
• Published: MDPI AG 2022
• Subjects: climate change; ice shelf; continental shelf; coastal polynya; benthic assemblages; benthic biodiversity; Biology (General); QH301-705.5; Antarctic; The Antarctic; Weddell; Weddell Sea; Antarc*; Ice Shelf; Ice Shelves
• Online Access: https://doi.org/10.3390/biology11121705; https://doaj.org/article/384533f5121b4d65aff82ee40ad5109a

Ice shelves cover ~1.6 million km 2 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.