Baseline pore-water nutrients, cations and DIC for sediment core SO268/1_56-1 (MUC-13) during RV SONNE cruise SO268/1 in the CCZ, Pacific Ocean@en

This baseline dataset comprises downcore measurements of pore-water nutrients, cations and DIC for a sediment core (MUC) retrieved in the framework of the European collaborative JPI Oceans MiningImpact project onboard R/V SONNE cruise SO268 in 2019. The scientific work during cruise SO268 was part of the second phase of the MiningImpact project (Environmental impacts and risks of deep-sea mining) and is designed to assess the environmental impacts of deep-sea mining of polymetallic nodules in the Clarion-Clipperton Zone (CCZ) in the Pacific Ocean. The pore water was extracted onboard by rhizon sampling. Pore-water nutrient concentrations (nitrate, nitrite, ammonium, silicic acid, phosphate) were analyzed onboard on freshly extracted pore water upon 3-fold dilution or undiluted (ammonium) using a QuAAtro continuous segmented flow analyzer (Seal Analytical). Major and minor elements were determined on acidified samples (25 µL double sub-boiling distilled concentrated HCl per 1 mL sample) using ICP-AES (iCAP 7400, Thermo Scientific) and DIC was determined on HgCl2-treated pore-water samples using a QuAAtro continuous segmented flow analyzer (Seal Analytical) at the Marine Geochemistry Lab, Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Bremerhaven.本基准数据集包含2019年搭载索涅号（R/V SONNE）科考航次SO268，依托欧洲海洋联合规划倡议（JPI Oceans）旗下MiningImpact合作项目所获取的沉积物岩芯（MUC）的孔隙水营养盐、阳离子及溶解无机碳（DIC）沿岩芯深度的测量数据。本次SO268航次的科考工作属于MiningImpact项目第二阶段（深海采矿的环境影响与风险）的组成部分，旨在评估太平洋克拉里昂-克利珀顿区（CCZ）多金属结核深海采矿的环境影响。孔隙水采用Rhizon采样法（Rhizon sampling）在航次现场完成提取。孔隙水营养盐浓度（硝酸盐、亚硝酸盐、铵盐、硅酸、磷酸盐）在现场对新鲜提取的孔隙水进行分析：除铵盐采用未稀释样品外，其余营养盐经3倍稀释后，使用QuAAtro连续分段流动分析仪（Seal Analytical）完成检测。常量及微量元素通过电感耦合等离子体原子发射光谱法（ICP-AES，iCAP 7400型，赛默飞世尔科技（Thermo Scientific））对酸化后的样品（每1mL样品加入25μL二次亚沸蒸馏浓盐酸）进行测定；溶解无机碳（DIC）则采用经氯化汞（HgCl2）预处理的孔隙水样品，于不来梅港阿尔弗雷德·魏格纳研究所、亥姆霍兹极地与海洋研究中心海洋地球化学实验室，使用QuAAtro连续分段流动分析仪（Seal Analytical）完成检测。