Figure captions
Figure 1. Sampling stations in the Baltic Sea for the AL476 cruise (fauna; filled red circles) and black filled squares for the IOW stations (phytoplankton monitoring (Wasmund et al. 2017). The color gradient on the map shows showing surface concentration of the chlorophyll-a in April 15 2016 observed by satelite and supplemented by the results of the ecohydrodynamic model EcoSat (http://satbaltyk.iopan.gda.pl). The four pie charts present the relative biomass fraction of major taxonomic algal groups integrating three cruises from January to May 2016 (Wasmund et al. 2017). ‘Het.’ is an abbreviation for heterotrophic.
Figure 2. Linear discriminant function analysis based on δ13CEAA values of training data comprising of bacteria, fungi and marine phytoplankton (Larsen et al. 2013) and consumers from this study. The phytoplankton comprise of eight diatom samples (D1-D5; N1-N3), four chrysophytes (X1-X4), four haptophytes (H1 – H4), two chlorophytes (K1 & K2) and one cryptophyte (Y1) – see Larsen et al. (2013) for sample codes. The ellipses represent 95% confidence intervals of each endmember, and the arrows represent the relative weightings of the independent variables for creating the discriminant function.
Figure 3. Principal component analysis for functional groups using mean-centred δ13CEAA values of consumers from Kiel Bay and Arkona Basin. Values in parentheses are the percentage variations accounted by each axis. The two axes account for 82% of the variations. The ellipses signify 95% confidence boundaries for each group.
Figure 4. Principal component analysis for species using δ13CEAA values centred to the EAA mean of consumers from Kiel Bay (A) and Arkona Basin (B), respectively. Values in parentheses are the percentage variations accounted by each axis. In A and B, the first two axes account for 84% and 83% of the variations, respectively. The ellipses signify 95% confidence boundaries for each group.
Figure 5. Principal component analysis with δ13CEAA values centred to the EAA mean of herring (A) and sprat (B), respectively. The convex hulls represent the maximum range in PC1 and PC2 scores for each of the four sampling locations. The most important EAA for variations among locations are displayed in two first ordination components. Values in parentheses are the percentage variations accounted by each axis. In A and B, the first two axes account for 95% and 92% of the variations, respectively.
Figure 6. Bulk δ13C and δ15N values of Kiel Bay and Arkona Basin consumers of major functional groups. The scatterplots show bulk δ13C and δ15N are uncorrelated; however, trophic structuring is apparent from the marginal density plots. Bulk isotope values of pelagic predators are missing (Table S3).
Figures
Figure 1