IMIS

The present dataset contains results on spine regeneration, coelomic fluid, mineral content and RNA/DNA ratio of a sub-polar sea urchin species Arbacia dufresnii when exposed to three pH treatments: 7.4, 7.7 and 8.0 (control), for 21 days, while fed ad libitum. All the experimental work, from the collection to the exposure took place in Punta Arenas, Chile, between November and December 2008, at the Centro de Cultivos Marinos Bahía Laredo. The goal of this work was to assess the effects of ocean acidification on the sea urchin A. dufresnii, from a sub-polar population (Punta Arenas region, Chile). During the exposure, water physicochemical conditions were measured using a conductivity meter pH/Cond 340 i WTW (USA) for the salinity, and an 827 pH Lab Metrohm meter (Switzerland) with a combined glass electrode (Metrohm 6.0228.010 with temperature sensor) calibrated with pHNIST buffers 4 and 7 (Merck CertiPUR®, Germany) for the temperature and pHNIST. The electromotive force (e.m.f.) was further assessed, to estimate pH in total scale (pHT). The Magnesium and Calcium content of both seawater and the coelomic fluid were measured using Inductively Coupled Plasma Atomic Emission Spectrometer (ICP-AES). Then, the Magnesium content of a pool of 3 spine regenerates coming from single individuals was measured using a flame atomic spectrometry (F-AAS), and the height of the regenerated part using ImageJ 1.33 u (Wayne Rasband, National Institutes of Health, USA). In coelomic fluid, the pHNIST and e.m.f. were measured using a microelectrode (Metrohm 6.0228.100), and the pHT was calculated. Lastly, the RNA/DNA ratio, a proxy of metabolic activity, was assessed in the gonads and body wall using a one dye (ethidium bromide)/one-enzyme (RNase), 96-well microplate fluorometric assay. Finally, all data were processed using the software Rstudio (version 2024.09.1) with appropriate statistical analysis.