10.1594/PANGAEA.972505van Kaam, Rianne J MRianne J Mvan Kaam0000-0002-9410-8447PANGAEA2025Adsorptiondissolved organic carbon (DOC)Ephemeral riverMineral dustNamibiaSorption experimentsEvent labelType of studySample code/labelDust, addedCarbon, organic, totalδ13C, total organic carbonδ13C, total inorganic carbonDust sampleIsotope ratio mass spectrometry (IRMS), Delta V Plus (Thermo Scientific) coupled via a ConFlo IV interface to an elemental analyserIsotope ratio infrared spectrometry (IRIS) with universal reference interface (URI) connection, Delta Ray (Thermo Scientific)Center for Marine Environmental Sciences (MARUM)2023-04-22T00:00:00/2023-04-23T00:00:00Dataset10.1594/PANGAEA.97250710.1016/j.marchem.2025.10453190 data pointstext/tab-separated-valuesCreative Commons Attribution 4.0 InternationalDifferent amounts of dust (5 mg and 100 mg) were added to a mixture (30 mL) of artificial seawater and 13C-labeled Spirulina extract (~500 µM). Water samples were taken at multiple time points (0, 10, 24, 48, 72, 120, and 168 hours) and analyzed for DOC using a carbon analyzer (multiN/C 2100s, Analytik Jena). Dust samples were analyzed for TOC and δ13C-TOC before and after the experiments using isotope ratio mass spectrometry (IRMS) (Delta V Plus, Thermo Scientific, with a ConFlo IV interface to an elemental analyzer), calibrated against the Vienna Pee Dee Belemnite (VPDB) standard with a precision of ±0.35‰. After 72 hours, water samples were also analyzed for δ13C-DIC using isotope ratio infrared spectrometry (IRIS) with a universal reference interface (URI) (Delta Ray, Thermo Scientific), calibrated to the VPDB standard with a precision of ±0.05‰.14.508415.0394-23.5629-21.899Kuiseb, Gobabeb, NamibiaKuiseb, Rooibank, NamibiaOmaruru, NamibiaGerman Research Foundationhttps://doi.org/10.13039/501100001659390741603EXC 2077: The Ocean Floor – Earth's Uncharted Interface