Monitoring of phenolic compounds in Antarctic Krill - a warning signal for the Southern Ocean food web

Despite Antarctica’s remoteness, human-derived pollutants are increasingly being detected in this ecosystem. This study examines the presence of phenolic compounds: Bisphenol A (BPA), 4-tert-octylphenol (4-t-OP), and 4-nonylphenol (4-NP) in Antarctic krill (Euphausia superba), a keystone species in the Southern Ocean food web. E. superba samples were collected from a single station near Elephant Island in two hauls: day (with observed high abundance of predators) and night. Sampling took place during the FINWAP: Comprehensive Assessment of a Fin Whale (Balaenoptera physalus) project expedition in 2023, aboard RV Maria S. Merian. Samples were analyzed using high-performance liquid chromatography (HPLC) with fluorescence detection. The results revealed measurable concentrations of BPA, 4-t-OP, 4-NP in krill tissue, with higher levels in samples from a daytime haul - when high abundance of predators, especially fin whales was observed. Phenolic compound concentrations often exceeded those reported previously in Pygoscelis penguin’s guano and feathers from King George Island (WG-EMM-2024/51). Comparisons with Baltic Sea zooplankton also showed unexpectedly high levels of those compounds in Antarctic krill, raising concerns about broader ecological consequences. These findings underscore the urgent need for expanded monitoring of anthropogenic contaminants across Antarctic ecosystems.