Recovery of Paleodictyon patterns after simulated mining activity on Pacific nodule fields

Abstract Since the late 1980s, various experiments have been conducted in polymetallic nodule fields of Pacific Ocean to assess potential environmental impacts future mining, specifically two areas: Peru Basin and Clarion-Clipperton Fracture Zone (CCZ). Two expeditions, SO242/2 2015 (Peru Basin) SO268/1 + 2 2019 (CCZ), deployed a towed camera system collect imagery from both areas. These expeditions aimed recovery fauna short (few weeks) long term (several years) following physical seafloor disturbance actions designed mimic by ploughs, dredges epibenthic sleds. Within collected image data, several strikingly hexagonal hole patterns were observed identified as Paleodictyon nodosum , an irregular form traces, on undisturbed disturbed areas seafloor. Recent forms occur abundantly deep-sea regions, but their origin, how they represent mode life forming organism, remains unknown. In this study, imaged occurrences traces sheds light lifecycle demonstrating that can recolonize habitat produce trace network few weeks. Nevertheless, density these substrates was lower than regions. We therefore hypothesize that, along with other benthic fauna, structures organism are impacted disturbance, even 26 years after densities sediments not recovered levels.