Table_1_Environmental Drivers of Mesophotic Echinoderm Assemblages of the Southeastern Pacific Ocean.xlsx

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

东南太平洋海域的中层生态系统（深度50-400米）因采样过程中所面临的物流挑战而鲜有研究。本研究旨在探讨氧浓度及其他环境预测因子如何解释这些中层系统中棘皮动物群落的变异，该类群是这些系统中主要的生物群落之一。我们整理了91个采样站点的棘皮动物物种数据，数据来源于1950年至2019年间的历史和近期调查，覆盖了约3700公里的经度梯度，并包括纳兹卡、萨拉·戈梅斯和胡安·费尔南德斯海脊。本研究应用了基于单变量和多变量模型的分析工具，以分析底栖动物群落的模式与环境因素之间的关系。我们的结果表明，棘皮动物物种丰富度与深度、氧浓度和盐度之间存在显著的正相关关系。棘皮动物群落组成的变化可被氧浓度、经度和叶绿素a含量显著解释。我们在大约101°W和86°W附近观察到显著的物种更替，这些区域的站点群落数据表现出更高的变异性。这种更替可能反映了物理障碍对扩散（例如，洋流）和栖息地变化的效应。在复活节岛和德斯文图拉斯岛附近观察到的棘皮动物群落，表现出高比例的潜在特有物种和独特的物种组合。本研究首次评估了东南太平洋海域中层棘皮动物群落的结构，并沿大尺度空间进行。所报告的信息有助于为东南太平洋新近设立的广阔海洋保护区设计适当的管理工具。