Comparison of measured salinity at 33m from the Arkona Basin and oxygen content in the Bornholm Basin from modeled data.

<p>Time series of salinity measured at the 33m depth level (Arkona Basin platform) operated by the Federal Maritime and Hydrography Agency, Hamburg, Germany is shown in daily resolution in the upper panel. Lower panel represents vertically mean oxygen concentration data (averaged between 60 and 90m) of the Bornholm Basin taken from the hydrodynamic model runs (BSIOM). Monthly means are indicated as horizontal lines.</p

Overview of the Baltic Sea region.

<p>Main basins of the Baltic Sea are indicated in abbreviated form by AB (Arkona Basin), BB (Bornholm Basin), GD (Gdansk Deep) and GB (Gotland Basin). The black frame indicates the scope of the more detailed map in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0196477#pone.0196477.g002" target="_blank">Fig 2</a>. Bathymetric data ETOPO1 are taken from Amante and Eakins [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0196477#pone.0196477.ref018" target="_blank">18</a>].</p

Correlation coefficients of salinity at 33m depth for different months in the Arkona Basin vs. oxygen concentration at various depths for successive months in the Bornholm Basin.

<p>Time series of monthly mean values for the correlations were taken from hydrodynamic model runs (BSIOM) hindcasting the period 1970–2015. From the entire period November to March salinity values at the 33m depth level in the Arkona Basin were correlated respectively to the vertical oxygen distribution in the Bornholm Basin between November and May. The value of the correlation coefficient is depicted in colour code for each combination of months selected for salinity and oxygen values and additionally the corresponding depth layer in the Bornholm Basin. The significance of each correlation is depicted with asterisks as follows: p>0.05 = no asterisk, p<0.05 = *, p<0.01 = **, p<0.001 = ***.</p

Statistical parameter and cross validation results of the linear functions shown in Fig 6.

<p>Statistical parameter and cross validation results of the linear functions shown in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0196477#pone.0196477.g006" target="_blank">Fig 6</a>.</p

Oxygen concentration time series for the Bornholm Basin on neutral egg buoyancy levels for the period 1971–2015.

<p>The density levels represent neutral buoyancy of Eastern Baltic cod eggs spawned by old (1009 kg m^-3, top panel), middle aged (1011 kg m^-3, middle panel), or young females (1013 kg m^-3; bottom panel), respectively. Dots and solid lines represent monthly mean values in April of the years 1971–2015 and shaded areas the differences to the monthly mean values in August of the same year. Data was taken from hydrodynamic model runs (BSIOM).</p

Detailed map of the south-western Baltic Sea.

<p>The white dot indicates the location of the observational platform in the Arkona Basin. Areas selected for vertically resolved hydrodynamic model data are depicted in shaded areas around the platform and additionally in the Bornholm Basin. Bathymetric data taken from the hydrodynamic Kiel Baltic Sea Ice-Ocean Model described in e.g.[<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0196477#pone.0196477.ref026" target="_blank">26</a>].</p

Statistical parameters of linear regressions shown in Fig 5.

<p>Statistical parameters of linear regressions shown in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0196477#pone.0196477.g005" target="_blank">Fig 5</a>.</p

Correlations of monthly mean salinity values in the Arkona Basin at 33m depth vs. oxygen content and oxygen-related egg survival in the Bornholm Basin.

<p>The explanatory variable in all panels is the maximum monthly mean salinity value between January and March at the 33m depth level in the Arkona Basin for the years 1971 to 2015. As dependent variables the mean oxygen condition and oxygen related egg survival probabilities in the Bornholm Basin in April of the same year were chosen. Panel A shows the linear correlation to the mean oxygen content in the depth range from 70 to 95m; B, C and D, the correlations to the oxygen-related Eastern Baltic cod egg survival probability at the egg neutral buoyancy level 1009, 1011 and 1013 kg m^-3, respectively. Linear regression lines are shown in red and the 95% confidence intervals as gray shaded areas.</p

Oxygen content relationships in the Bornholm Basin on neutral egg buoyancy levels between the beginning (April) and the rest of the spawning season (Integral May-Aug).

<p>Monthly means of the oxygen content on 3 density levels in the Bornholm Basin derived from hydrodynamic model runs (BSIOM) hindcasting the period from 1971 until 2015 were used for the analysis. The density levels represent neutral buoyancy of eggs spawned by old (1009 kg m^-3, left panel), middle aged (1011 kg m^-3, middle panel), and young females (1013 kg m^-3, right panel), respectively. Linear regression lines are shown in red and the 95% confidence intervals as gray shaded areas. Regression parameters are shown in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0196477#pone.0196477.t001" target="_blank">Table 1</a>. Δ = represents years in which the density layer did not exist for the entire spawning season.</p

Population recruitment under ocean acidification (OA) for Western Baltic cod (black line and symbols) and Barents Sea cod (grey line and symbols).

<p>Recruitment is given relative to a baseline scenario of no OA and spawning stock biomass at ICES precautionary biomass levels (B_PA) in dependence of the duration of OA-induced mortality. Two important points in larval development are highlighted. Standard deviations displayed only for selected days to improve readability.</p