Rock outcrops enhance abyssal benthic biodiversity

Abyssal polymetallic nodule fields represent a unique deep-sea habitat. The hard substratum provided by nodules is thought to increase habitat complexity, promoting the occurrence of highly diverse abyssal assemblages. However, in these habitats also available as outcropping rock fragments, but their contribution heterogeneity has been largely overlooked. Here, we assessed if type and size can modulate benthic biodiversity at local scales within Clarion Clipperton Zone (N Pacific abyss). We compared megafauna (animals >10 mm) assemblages bearing with those areas containing rocks addition nodules. found lower faunal density clearly higher diversity more heterogenous composition only In addition, patch appeared positively influence some taxa, like bamboo corals. These results suggest that rocks, nodules, constitute keystone structures enhancing fields. Rock appear common plains may make regionally-important contributions biodiversity, suggesting they be relevant include conservation efforts.