Fig. 8: Correlation between δ18O and δ2H values and salinity in June 2019, March 2020, and July 2020. Linear and hyperbolic trendlines for Schlei (solid) and combined Darß-Zingster and Rügener Bodden (dashed) samples, under exclusion of outliers as derived from lakes and the open Baltic Sea.
The spatial trends in water isotopes as visualized in Fig. 7 are illustrated as correlation crossplots between δ-values and salinities in Fig. 8. Those reveal a positive correlation for samples from March 2020 (isotope amplitude ca. 30 ‰ δ2H and 5.5 ‰ δ18O over ca. 20 salinity units). In contrast, samples from July 2020 reveal hyperbolic correlations between the two parameters (Fig. 8). Here, δ-values reach a plateau of maximum values for salinities >7. For some samples, a reversal towards lower δ-values with increasing salinities is observable. A similar trend is observable in samples from June 2019, which were taken in lower spatial resolution (Fig. 8).