The primary dataset consists of 2055 data points, extracted from 31 peer-reviewed publications, identified through a comprehensive and systematic literature search of scholarly articles published between 1967 and 2022. From these studies, data containing simultaneously collected SML and ULW concentrations were extracted for twelve different observational types of organic compounds.The TOC pool includes all forms of organic carbon, thus comprising both POC and DOC. Similarly, the TON pool combines both PON and DON. In general, the particulate pool constitutes a minor fraction of the total pool.All the data were collected either (1) directly from the source when available, or else (2) through digitization of graphs and plots using PlotDigitizer (https://plotdigitizer.com) and GraphClick v3.0 (https://graphclick.en.softonic.com/mac) or, (3) via author correspondence when data were not available in the published materials. The different data extraction methods are flagged.

This dataset contains measurements of organic matter (OM) concentrations in both the surface microlayer (SML) and underlying waters (ULW), along with the corresponding enrichment factors (EF). The SML is a critical boundary layer where concentrations of organic compounds may differ significantly from the ULW due to biological, physical and chemical processes. Enrichment factors, calculated by comparing concentrations in the SML to those in the ULW are included to quantify the degree of accumulation or depletion of organic matter in the SML. The dataset is compiled from data published in the literature, unpublished data collected upon request and data from mesocosm experiments. The twelve different observational types of organic compounds are1) total organic carbon (TOC in mg/l), 2) particulate organic carbon (POC in mg/l), 3) dissolved organic carbon (DOC in mg/l), 4) total organic nitrogen (TON in mg/l), 5) particulate organic nitrogen (PON in mg/l), 6) dissolved organic nitrogen (DON in mg/l), 7) amino acids (AA in μmol/l), 8) fatty acids (FA in μg/l), 9) transparent exopolymer particles (TEP in μg Xeq/l), 10) carbohydrates (CHO in μmol/l), 11) lipids (in μmol/l),12) proteins (in μmol/l).Further references:Carlucci, A.F., Craven, D.B., Henrichs, S.M., 1985. Surface-film microheterotrophs: amino acid metabolism and solar radiation effects on their activities. Marine Biology, 85(1), 13-22. https://link.springer.com/content/pdf/10.1007/BF00396410.pdfHillbricht-Ilkowska, A., Kostrzewska-Szlakowska, I., 2004. Surface microlayer in lakes of different trophic status: nutrients concentration and accumulation. Pol. J. Ecol. 52, 461–478.Meyers, P.A., 1980. Dissolved Fatty Acids and Organic Carbon in Sea Water from the Fringing-Barrier Reef at Discovery Bay, Jamaica. Bull. Mar. Sci. 30, 657–666.