Spatial and temporal dynamics of Antarctic shallow soft-bottom benthic communities: ecological drivers under climate change

• Published in: BMC Ecology
• Main Authors: Belinda J. Vause, Simon A. Morley, Vera G. Fonseca, Anna Jażdżewska, Gail V. Ashton, David K. A. Barnes, Hendrik Giebner, Melody S. Clark, Lloyd S. Peck
• Format: Article in Journal/Newspaper
• Language: English
• Published: BMC 2019
• Subjects: Disturbance ecology; Patchiness; Seasonality; Latitudinal comparisons; Sediment properties; Ecology; QH540-549.5; Antarctic; Antarctic Peninsula; Rothera; Rothera Point; South Cove; Antarc*; Iceberg*
• Online Access: https://doi.org/10.1186/s12898-019-0244-x; https://doaj.org/article/907b544343df4a98bbfd6cf1864a62be

Abstract Background Marine soft sediments are some of the most widespread habitats in the ocean, playing a vital role in global carbon cycling, but are amongst the least studied with regard to species composition and ecosystem functioning. This is particularly true of the Polar Regions, which are currently undergoing rapid climate change, the impacts of which are poorly understood. Compared to other latitudes, Polar sediment habitats also experience additional environmental drivers of strong seasonality and intense disturbance from iceberg scouring, which are major structural forces for hard substratum communities. This study compared sediment assemblages from two coves, near Rothera Point, Antarctic Peninsula, 67°S in order to understand the principal drivers of community structure, for the first time, evaluating composition across all size classes from mega- to micro-fauna. Results Morpho-taxonomy identified 77 macrofaunal species with densities of 464–16,084 individuals m−2. eDNA metabarcoding of microfauna, in summer only, identified a higher diversity, 189 metazoan amplicon sequence variants (ASVs) using the 18S ribosomal RNA and 249 metazoan ASVs using the mitochondrial COI gene. Both techniques recorded a greater taxonomic diversity in South Cove than Hangar Cove, with differences in communities between the coves, although the main taxonomic drivers varied between techniques. Morphotaxonomy identified the main differences between coves as the mollusc, Altenaeum charcoti, the cnidarian Edwardsia sp. and the polychaetes from the family cirratulidae. Metabarcoding identified greater numbers of species of nematodes, crustaceans and Platyhelminthes in South Cove, but more bivalve species in Hangar Cove. There were no detectable differences in community composition, measured through morphotaxonomy, between seasons, years or due to iceberg disturbance. Conclusions This study found that unlike hard substratum communities the diversity of Antarctic soft sediment communities is correlated with the same factors as ...