(Table S1) General information of solid phase extracted dissolved organic matter from porewater and overlying bottom water collected during Maria S. Merian cruise MSM29 and Polarstern cruise PS85 to the Fram Strait@en

Molecular analysis of dissolved organic matter in overlying bottom water and porewater was performed on a Solarix FT-ICR-MS equipped with a 15 Tesla superconducting magnet (Bruker Daltonic) using an electrospray ionization source (Bruker Apollo II) in negative ion mode. Molecular formula calculation for all samples was performed using a Matlab (2010) routine that searches, with an error of < 0.5 ppm, for all potential combinations of elements including the elements C∞, O∞, H∞, N ≤ 4; S ≤ 2 and P ≤ 1. Combination of elements NSP, N2S, N3S, N4S, N2P, N3P, N4P, NS2, N2S2, N3S2, N4S2, S2P was not allowed. Mass peak intensities are normalized relative to the total molecular formulas in each sample according to previously published rules (Rossel et al., 2015; doi:10.1016/j.marchem.2015.07.002). Additionally, the contribution of molecular formulas with different elemental composition (carbon = C; hydrogen = H; oxygen = O; nitrogen = N; sulfur = S; phosphorus = P) is expressed as a percentage of the total intensity in each sample. Furthermore, in this table,Molecular weight~wa~ was calculated considering the intensity of the mass peak in each sample (i.e. wa stands for intensity weighted-average).本研究采用搭载15特斯拉超导磁体（布鲁克道尔顿公司，Bruker Daltonic）的Solarix型傅里叶变换离子回旋共振质谱（FT-ICR-MS），搭配布鲁克Apollo II型电喷雾电离源，以负离子模式对上覆底层水与孔隙水中的溶解有机质开展分子层面分析。所有样品的分子式计算均通过Matlab 2010脚本完成，该脚本以小于0.5 ppm的质量误差阈值，检索包含碳（C）、氧（O）、氢（H）（用量无限制）、氮（N）≤4、硫（S）≤2及磷（P）≤1的所有潜在元素组合；同时禁止以下元素组合：NSP、N₂S、N₃S、N₄S、N₂P、N₃P、N₄P、NS₂、N₂S₂、N₃S₂、N₄S₂及S₂P。质谱峰强度按照已发表的规则（Rossel等，2015；doi:10.1016/j.marchem.2015.07.002），以每个样品的总分子式数为基准进行归一化处理。此外，不同元素组成（碳=C、氢=H、氧=O、氮=N、硫=S、磷=P）的分子式对总强度的贡献，以各样品总强度的百分比形式呈现。本表格中的分子量~wₐ~以各样品的质谱峰强度为权重计算得到（即wₐ代表强度加权平均值）。