Marine productivity (MP) plays a crucial role in the Earth’s system by absorbing atmospheric CO2. In the Arctic, due to global warming and sea-ice reduction, MP has increased up to 50% over the last decades, suggesting that Arctic waters can become even more productive in the future, thus providing additional carbon export capacities. To understand how MP can evolve under future climate scenarios, the past reconstruction of its variability is necessary. To perform long-term MP studies through ice core analyses, research is ongoing to identify reliable MP proxies, i.e. molecules that are directly or indirectly linked to phytoplankton blooms. Past investigations focused on a limited suite of molecules (e.g. methanesulphonic acid (MSA), unsaturated fatty acids) that showed some limitations, i.e. low atmospheric lifetimes or poor preservation in the ice. During blooms, phytoplankton also emits isoprene, a molecule that is oxidized into the atmosphere to secondary organic aerosol (SOA) species. Despite SOAs accounting for a large component of total organic aerosol, only a small fraction of it has been characterized so far. Today, thanks to advances in high-resolution mass spectrometry and in the development of non-target screening (NTS) workflows, it is possible to determine the molecular composition of hundreds of different SOA tracers from single ice/snow samples. In BioProxies, we aim at applying a groundbreaking NTS method to identify new SOA tracers in snow and to define, among them, those that can be exploited as new MP proxies. To this purpose, daily snow samples will be collected at Gruvebadet before and during the phytoplankton bloom and analyzed for major ions, MSA, stable water isotopes and for NTS analyses. Insights on SOA’s preservation in firn matrices as well as on their occurrence in areas far from the marine source will be also assessed through the analysis of a shallow firn core (Holtedahlfonna) and snowpit samples (Austre Brogerbreen).