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

Accepted version
Peer-reviewed

Change log

Authors

Khan, Tasnuva Ming 
Griffiths, Huw J 
Whittle, Rowan J 
Stephenson, Nile P 
Delahooke, Katie M 

Abstract

jats:pPredator-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 (&gt;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 jats:italicin situ</jats:italic> 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 jats:italicPolarstern</jats:italic> (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/mjats:sup2</jats:sup>). 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 ecosystem-regulating impact that they do on shallow Antarctic epibenthic communities.</jats:p>

Description

Keywords

37 Earth Sciences, 31 Biological Sciences, 3103 Ecology, 14 Life Below Water

Journal Title

Frontiers in Marine Science

Conference Name

Journal ISSN

2296-7745
2296-7745

Volume Title

Publisher

Frontiers Media SA
Sponsorship
Natural Environment Research Council (NE/S014756/1)
This work has been supported by Natural Environment Research Council (NERC) Independent Research Fellowship NE/S014756/1, awarded to EGM. TMK is funded by a Cambridge International and Newnham College Scholarship, administered by Cambridge Trust. RJW and HJG are funded by UK Research and Innovation (UKRI) Future Leaders Fellowship MR/W01002X/1 “The past, present and future of unique cold-water benthic (seafloor) ecosystems in the Southern Ocean” awarded to RJW. HJG is also funded by BIOPOLE, funded by the NERC, part of UKRI, under the National Capability Science Multi-Centre award scheme (NC-SM2)