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Temperature (T), salinity (S), dissolved oxygen (DO) concentration, oxygen saturation (DOsat), oxidation reduction potential (Eh), pH and the concentrations of sulfate (SO42–), hydrogen sulfide (H2S), phosphate (PO43–) and ferrous iron (Fe(II)) in water above the sediment measured in the Gdansk Deep during the summer and winter voyages (T, S and DO was measured 1 m and other parameters several cm above the sediment surface)
| Voyage | Site | T (°C) | S | DO (cm3 dm–3) | DOsat (%) | Eh (mV) | pH | SO42– (mmol dm–3) | H2S (μmol dm–3) | PO43– (μmol dm–3) | Fe(II) (μmol dm–3) |
|---|---|---|---|---|---|---|---|---|---|---|---|
| VIII 2015 | P1 | 7.27 | 13.37 | 0.86 | 11 | 162 | 7.81 | 16.19 | 1.10 | 12.56 | 0.13 |
| P1A | 7.32 | 13.21 | 1.43 | 18 | 224 | 7.80 | 14.90 | 0.00 | 8.21 | 0.18 | |
| P1B | 7.22 | 13.39 | 1.51 | 19 | 247 | 7.78 | 15.59 | 0.00 | 12.66 | 0.23 | |
| II 2016 | P1 | 6.32 | 12.31 | 0.58 | 7 | 92 | 7.90 | 4.99 | 27.22 | 27.27 | 0.42 |
| P1A | 6.63 | 11.44 | 1.17 | 15 | 194 | 7.90 | 11.04 | 17.80 | 24.66 | 0.51 | |
| P1B | 6.35 | 11.45 | 1.37 | 17 | 217 | 7.88 | 10.63 | 20.85 | 25.68 | 0.53 |
Benthic fluxes of phosphate (FPO43–) and iron (FFe(II)) in different regions of the Baltic Sea
| Region | Estimation method | FPO43– (μmol m–2 hr–1) | References |
|---|---|---|---|
| Gullmarsfjorden | Porewater gradient calculations | 5.42 | Sundby et al. 1986 |
| Gulf of Finland | 0.002–0.07 | Ignatieva 1999 | |
| Gulf of Gdansk | –0.1–7.9 | Graca 2009 | |
| Gdansk Deep | 5.3–5.7 | Graca et al. 2006 | |
| 2.12–2.56 | Łukawska-Matuszewska & Burska 2011 | ||
| Puck Bay | 0.04–3.17 | Bolatek 1992 | |
| Gotland Basin | Chamber incubations | –0.13–15.67 | Viktorsson et al. 2013 |
| 8.33–9.58 | Noffke et al. 2015 | ||
| Region | Estimation method | FFe(II) (μmol m–2 hr–1) | References |
| Gullmarsfjorden | Porewater gradient calculations | 0.83 | Sundby et al. 1986 |
| Gulf of Finland | Sediment core incubation | 3.93 | Lehtoranta & Heiskanen 2003 |
| Gulf of Finland | Chamber incubations | 5.84 fluxes of dissolved total iron | Almorth et al. 2009 |
| 0.21 fluxes of dissolved total iron | Pakhomova et al. 2007 | ||
| Vistula Lagoon | 4.16 fluxes of dissolved total iron | Pakhomova et al. 2007 |
Benthic fluxes of phosphate (FPO43–) and ferrous iron (FFe(II)) and parameters used for calculations
| Voyage | Site | Porosity | Diffusion coefficient in sediment (10–6 cm2 s–1) | Concentration gradient in surface sediment (δC δz–1) (μmol dm–3cm–1) | Benthic flux (μmol m–2 hr–1) | |||
|---|---|---|---|---|---|---|---|---|
| PO43– | Fe(II) | PO43– | Fe(II) | FPO43– | FFe(II) | |||
| VIII 2015 | PI | 0.975 | 5.034 | 4.932 | 9.468 | 0.018 | 1.67 | 0.31 × 10–2 |
| P1A | 0.975 | 4.145 | 4.060 | 18.57 | 0.046 | 2.70 | 0.62 × 10–2 | |
| P1B | 0.975 | 5.040 | 4.937 | 8.618 | 0.029 | 1.53 | 0.50 × 10–2 | |
| II 2016 | P1 | 0.983 | 4.321 | 4.233 | 10.645 | 0.021 | 1.63 | 0.31 × 10–2 |
| P1A | 0.983 | 4.322 | 4.234 | 16.888 | 0.078 | 2.58 | 1.17 × 10–2 | |
| P1B | 0.983 | 4.323 | 4.233 | 16.580 | 0.084 | 2.54 | 1.25 × 10–2 | |