Dataset: Microcosm Experiments Reveal Source-Specific Impacts of Atmospheric Aerosols on Plankton Communities and Organic Matter in the Sea Surface Microlayer of the Adriatic Sea

Aerosol Analyses: Aerosol AA and BB materials were analysed for anions (Cl-, NO3-, NO2-, SO42-, PO43-) and cations (Na+, NH4+, K+, Ca2+, Mg2+) by ion chromatography with suppressed conductivity detection on dual channel capillary ion chromatograph (ICS-5000, Thermo Fisher Scientific, USA) as described in detail in Gluščić et al. (2023). Trace metals (V, Mn, Fe, Co, Ni, Cu, Zn, As, Sr, Cd, Pb, Al) were determined by inductively coupled plasma mass spectrometry (ICP-MS 7500cx, Agilent Technologies, Germany), after sample digestion in an UltraCLAVE digestion system (Milestone Srl, Italy) as described in detail in Penezić et al. (2021). Water soluble organic carbon (WSOC) was determined after filtration of PM water extracts (0.7 μm GF/F filters, Whatman, UK; pre-combusted at 450 °C for 5 h) by TOC-VCPH analyser (Shimadzu, Japan) by standardized thermo-optical methods. Filter extracts re-dissolved in acetonitrile were analysed for polycyclic aromatic hydrocarbons (PAH; list in Supporting Information, Table S1) using high-performance liquid chromatography with a fluorescence detector (1260 Infinity, Agilent Technologies, USA) as described in Jakovljević et al. (2021). Analysis of nitroaromatic compounds (NAC: list in Table S1) has been performed by UltiMate 3000 UHPLC system (Thermo Scientific, USA) coupled with a triple quadrupole/linear ion trap mass spectrometer (Agilent Technologies, USA), following the procedure described in Frka et al. (2022).Seawater Analyses: Detailed procedures for the analyses of nutrients, organic carbon, surface-active substances, phytoplankton, and microbial community abundances are described in detail in Milinković et al. (2022) and are also available in the Appendix 2 of the Supporting Information. Briefly, to determine nutrient (dissolved NO3-, NO2-, NH4+ and PO43-), dissolved (DOC) and particulate organic carbon (POC) concentrations, seawater aliquots were filtrated through 0.7 μm GF/F filters (Whatman, UK) pre-combusted at 450 °C for 5 h. Nutrient concentrations were determined spectrophotometrically. Total dissolved inorganic nitrogen (DIN) concentrations were calculated as the sum of concentrations of all dissolved N species measured. DOC measurements were conducted using a TOC-VCPH analyser (Shimadzu, Japan) with standardized thermo-optical methods. Filters for POC were dried and analysed via elemental analyser (Flash EA 1112, Thermo Scientific, USA). Concentrations of surfactants or surface-active substances (SAS), expressed in equivalents of non-ionic surfactant tetra-octylphenolethoxylate (mg T eq. L-1), were determined by phase sensitive alternating current (ac.) voltammetry. The initial chemical characteristics of the SML and ULW are presented in the Appendix 3, Table S3. Composition and abundance of nanophytoplankton (NP; 2 - 20 µm) and microphytoplankton (MP, 20 - 200 µm) were assessed through microscopy, while heterotrophic bacteria (HB), also classified into high nucleic acid (HNA) and low nucleic acid (LNA) bacteria, Prochlorococcus (Pro), Synechococcus (Syn), picoeukaryotes (hereafter picophytoplankton, PP) and heterotrophic nanoflagellate communities (HNF) were determined through flow cytometry. Note that the abundance of MP and NP was determined at 0, 40, and 88 h, while the abundances of other communities were measured at 0, 18, 40, 64 and 88 h.The dataset of the microcosm experiment is archived as a supplement to the manuscript submitted for the review process.