Network analyses on photographic surveys reveal that invertebrate predators do not structure epibenthos in the deep (~2000m) rocky Powell Basin, Weddell Sea, Antarctica

• Published in: Frontiers in Marine Science
• Main Authors: Tasnuva Ming Khan, Huw J. Griffiths, Rowan J. Whittle, Nile P. Stephenson, Katie M. Delahooke, Autun Purser, Andrea Manica, Emily G. Mitchell
• Format: Article in Journal/Newspaper
• Language: English
• Published: Frontiers Media S.A. 2024
• Subjects: photographic survey; ecological network; predator-prey interaction; community composition; Antarctic Peninsula; starfish; Science; Q; General. Including nature conservation; geographical distribution; QH1-199.5; Antarc*; Antarctic; Antarctica; Weddell Sea
• Online Access: https://doi.org/10.3389/fmars.2024.1408828; https://doaj.org/article/3a4ede343e0e4d3792d4804b16892306

Predator-prey interactions in marine ecosystems control population sizes, maintain species richness, and provide intermediate disturbance. Such ecosystem structuring interactions may be rare in Antarctic epibenthic communities, which are unique among marine ecosystems worldwide for their dominance of soft bodied fauna (sponges, soft and hard corals, and echinoderms) and a simultaneous paucity of shell crushing predators (sharks, rays and durophagous decapods). In the shallow benthos, instead of durophagy, important Antarctic predators such as starfish, pycnogonids (sea spiders), nemertean worms, and nudibranchs employ grazing, scavenging, or sucking strategies. Far less is known about deep sea (>1000 m) Antarctic benthic communities due to the challenging nature of polar data collection, so that photographic surveys provide one of the only means of making in situ observations of these deep sea communities. We used seabed photographs of the deep (~2000m) slope of the Powell Basin, northwest Weddell Sea, taken by the Ocean Floor Observation and Bathymetry System on board the RV Polarstern (PS118, April 2019) to investigate the epibenthic community composition, and Bayesian Network Inference (BNI) to determine the ecological network, namely the ecological associations, including potential invertebrate predator-prey relationships between taxa. Photographs show that the rocky substrates of the basin slope support between 10-22 morphotaxa per photo, and highly abundant communities (density between 106 to 553 individuals/m2). BNI results reveal a network of associations between the sessile and mobile suspension and filter feeding organisms and their physical environment. However, associations between invertebrate predators like starfish, and other organisms, were not detected in the network. This lack of inclusion within the network suggests that, despite the presence of these normally important mobile predators, invertebrate predator-prey interactions on the rocky Powell Basin slope do not have the same ...