Megafaunal Ecology of the Western Clarion Clipperton Zone

The Clarion Clipperton Zone (CCZ) is a vast area of the central Pacific Ocean where abyssal seabed focus for future polymetallic nodule mining. Broad-scale environmental gradients occur east-to-west across CCZ seabed, including organic matter supply and abundance, factors that influence benthic faunal community structure function. A network protected areas CCZ, called Areas Particular Environmental Interest (APEIs), has been designated to cover this variation. Most previous studies environment megafaunal communities have focussed on eastern leaving impact these large-scale unexamined design untested. Seamounts are further source heterogeneity in region. We examined ecology three APEIs western spanning range conditions. used combination photography direct sampling assess megafauna soft sediment habitats plain APEIs, seamounts two those APEIs. found conditions plains differed between terms water depth, abundance coverage, particle size distribution, estimated flux. Megafauna were low density high diversity, with few common morphotypes sites many being observed only once. Xenophyophores dominated assemblages. diversity invertebrates greater at lower inputs abundance. same nodule-free had coarser sediments than plain. Invertebrate was plains, most recorded seamounts. Low morphotype overlap also suggests little connectivity adjacent plains. Our results provide first evaluation highlighting communities, important evaluating areas.