Deep-sea biodiversity at the extremes of the Salas y Gómez and Nazca ridges with implications for conservation

367.83, R2 = 0.419) (Table 3). Depth accounted for 22.68% of the variation followed by salinity (5.79%), crust age (4.83%), nitrate (4.58%), and broad-scale BPI (4.12%). Deployments by sub- regions were well-separated in ordination space and sites within Desventuradas had a greater spread and lower concordance compared to RN/SyG (Fig 9). dbRDA1 accounted for 59.04% of the fitted variation and 24.79% of the total variation. Depth (ρ = 0.947) was the major driver of dbRDA1. dbRDA2 accounted for 15.16% of the fitted variation and 6.37% of the total varia- tion, with the major drivers being crust age (ρ = -0.810), followed by nitrate (ρ = -0.385) and salinity (ρ = -0.384). Squalidae (ρ = -0.797), Triglidae (ρ = -0.627), Moridae (ρ = 0.519), and Synaphobranchidae (ρ = 0.509) were most highly correlated with dbRDA1. Gempylidae (ρ = 0.678), Sternoptychi- dae (ρ = 0.407), Polymixiidae (ρ = 0.350) and Moridae (ρ = 0.330) were most closely correlated with dbRDA2. The snake mackerel family (Gempylidae), primarily Rexea spp., was correlated with hard bottom sites at RN/SyG. Spiny dogfish sharks (Squalidae—Squalus spp.) and sea robins (Triglidae—Pterygotrigla picta) were most closely correlated with shallow sites at Fig 7. Distance-based redundancy analysis (dbRDA) ordination to investigate the relationship between the environmental variables and invertebrate assemblages. Bray-Curtis similarity matrix based on ln(x+1) transformed MaxN higher level invertebrate taxa. Symbol sizes are proportional to depth. https://doi.org/10.1371/journal.pone.0253213.g007 PLOS ONE

Deep-sea biodiversity along the Salas y Go´ mez and Nazca ridges PLOS ONE | https://doi.org/10.1371/journal.pone.0253213 June 30, 2021 14 / 27