Arctic nekton uncovered by eDNA metabarcoding: Diversity, potential range expansions, and pelagic‐benthic coupling

Abstract

The Arctic Ocean hosts a large biomass of uniquely adapted organisms. Its diversity is poorly sampled but intermediate relative to the world's oceans (~8000 extant species; Bluhm et al., 2011;

Long-term annual trawl data show shifts in cephalopod community in the western Barents sea during 18 years

“…Alternative methods to assess biodiversity and community composition in marine ecosystems are underwater video imagery and environmental DNA (eDNA) analyses (e.g., Merten et al, 2021;Kopp et al, 2023). Environmental DNA analysis enables detection of species based on genetic material from marine animals that is released in the environment, such as shed skin cells, mucus, gametes and faeces (Taberlet et al, 2012a, Taberlet et al, 2012b.…”

“…The advantages of eDNA analysis are that it gives a larger presence/ absence time frame than trawl surveys (eDNA remains suspended in the water column for up to 60 days), and it allows simultaneous identification of different taxa within the same water sample (reviews: Thomsen and Willerslev, 2015;Rourke et al, 2022). Advances and successes have been made with the application of eDNA in fisheries surveys (Thomsen and Willerslev, 2015;Rourke et al, 2022) and also in cephalopod biodiversity studies (e.g., Merten et al, 2021;Visser et al, 2021;Merten et al, 2023). While the technique is being developed to be used for abundance estimates (Thomsen and Willerslev, 2015;Rourke et al, 2022), it is currently mostly used to obtain presence-absence for species or communities.…”

“…Underwater imagery analyses has been applied in biodiversity assessments of cephalopod communities (e.g., Merten et al, 2021;Pratt et al, 2021, Pratt et al, 2023. For example, G. fabricii was recorded in the central Arctic Ocean under ice by a mooring camera system (Snoeijs-Leijonmalm et al, 2022), and Arctic cirrate octopods were documented to perform benthopelagic migrations (Golikov et al, 2023b).…”

“…Benthic cephalopods are often hard to identify to species level from images (e.g., Pratt et al, 2021;Robinson et al, 2021;Snoeijs-Leijonmalm et al, 2022; and many others). To summarise, currently trawling, eDNA and video imagery each have their strengths and weaknesses, and the best results are rendered by combining them (e.g., Thomsen et al, 2016;Merten et al, 2021;Kopp et al, 2023).…”

The Genomic Ghosts of Geukensia granosissima

“…For example, though many focus on the keystone consumer Pisaster in Paine's (1966) exclusion experiments, that work helped clarify how mussels -one of the primary prey items for Pisaster and many sea stars -are often important competitors for space in intertidal ecosystems as well as harboring incredibly diverse infaunal communities ( however, community change can be expected that doesn't rely on human-introduced diversity to a region (Canning-Clode et al 2011). Many species -particularly in marine ecosystems -appear to be redistributing themselves through recruitment to more suitable habitats, often poleward, and dwindling populations towards the equator in many cases (Sunday et al 2012, Poloczanska et al 2013Merten et al 2023). Many such studies rely on economically important taxa, which are data rich and more intensely monitored, for inference of redistribution.…”