Tourism associated chemical footprints in Antarctic coastal ecosystems

Surface seawater samples (30 mL, amber glass bottles) were collected manually in coastal areas of Port Foster. Six organic UV filters (HMS, BZ3, IMC, EHDP, EHMC, OC) were quantified using dispersive liquid-liquid microextraction followed by gas chromatography–mass spectrometry (DLLME-GC-MS). Two 72 h on-board phytoplankton exposure experiments were conducted using natural assemblages incubated in 2-L Teflon™ PFA bags under ambient Antarctic light and temperature conditions. Five concentrations of commercial SPF 50+ sunscreen formulations (6.25–75 mg L⁻¹) were tested in triplicate. Photophysiological parameters (Fv/Fm and %AChla) were measured using PHYTO-PAM-II fluorometry. Flow cytometry (BD Accuri™ C6 Plus) and Imaging Flow Cytometry (ImageStream®X Mk II) were used to characterize phytoplankton populations.