Environmental Drivers of Mesophotic Echinoderm Assemblages of the Southeastern Pacific Ocean

Mesophotic ecosystems (50–400 m depth) of the southeastern Pacific have rarely been studied because logistical challenges in sampling across this remote zone. This study assessed how oxygen concentrations and other environmental predictors explain variation echinoderm assemblages at these mesophotic systems, where group is among predominant fauna. We compiled data on taxa 91 stations, from historical recent surveys (between 1950 2019), covering a longitudinal gradient approximately 3,700 km along with Nazca, Salas y Gómez, Juan Fernández ridges. Uni- multivariate model-based tools were applied to analyze patterns benthic fauna relation factors. Our results indicate significant positive relationship between species richness depth, oxygen, salinity. Changes community composition significantly explained by longitude, chlorophyll- . observed notable turnovers ∼101 ∼86°W, tend be more variable stations. turnover possibly reflects effects physical barriers dispersion (e.g., currents) habitat changes. Echinoderm around Easter Desventuradas Islands presented high occurrence potentially endemic distinct assemblages. first assess structure Ocean large spatial scale. The information reported here could help design appropriate management for vast, recently created, marine protected areas Pacific.