Fig. 3: Time series of δ2H / δ18O values in water samples collected between 26th March 2020 to 16th March 2021 at A. P. Møller Skolen (APM Skolen), Schleswig (Kleine Breite, Schlei; sampling point A; Fig. 2a). Error bars indicate replicate measurements. Salinity, water temperature and pH measured in-situ during sampling. Data of daily mean values of water discharge derived from the major inflowing river Füsinger Au (LLUR, 2022). Major Baltic Sea salt inflow events at Great Belt and Øresund from (V. Mohrholz, 2018).