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Average annual primary production [g C m−2 yr−1] in different regions of the Baltic Sea in 1954–2013 (source: Renk 2000 – publication of NMFRI; unpublished data of NMFRI)
| Area | Study period | Primary Production | Author(s) |
|---|---|---|---|
| Kattegat | 1954–1960 | 97.5 | Steemann Nielsen 1965 |
| 1964–1969 | 90.4 | Gargas et al. 1978 | |
| 1988–1990 | 290 | Richardson & Christoffersen 1991 | |
| Belt Sea | 1953–1957 | 86 | Steemann Nielsen 1965 |
| 1975–1977 | 116.5 | Gargas et al. 1978 | |
| Belt Sea – Sound | 1972 | 70–77 | Edler 1978 |
| 1973 | 73–183 | ||
| Belt Sea – Kiel Bight | 1971–1793 | 158 | Bodungen et al. 1975 |
| Bornholm Basin – Arkona Deep | 1971–1974 | 85 | Renk 1983 |
| 1967–1978 | 94.3 | Schulz & Kaiser 1973 and 1976 | |
| Bornholm Basin – Mecklenburg Bight | 1969–1978 | 130 | Kaiser et al. 1981 |
| Bornholm Basin – Bornholm Deep | 1967–1972 | 59–138 | Schulz & Kaiser 1974 and 1975 |
| 1971–1975 | 95 | Renk 1983 | |
| 1987–1991 | 123 | Renk 1997 | |
| Gulf of Gdansk | 1971–1974 | 140 | |
| 1987 | 304 | ||
| 2004–2013 | 138–285 | unpublished data, NMFRI | |
| average: 229 | |||
| Gulf of Gdańsk – Puck Bay | 1965–1991 | 198 | Renk 1997 |
| Gulf of Gdańsk – Gdansk Deep | 1971–1974 | 107 | |
| 1981–1985 | 129 | ||
| 1987–1991 | 172 | ||
| Gotlańd Basin – Gotlańd Deep | 1970 | 38 | Schulz & Kaiser 1973 |
| 1973 | 91 | Ackefors & Lindahl 1975 | |
| 1974 | 116 | Lindahl 1977 | |
| 1987–1991 | 141 | Renk 1991 and 1997 | |
| Aland Sea | 1974–1976 | 66–94 | Lindahl 1977 |
| Bothnian Bay | 1973–1974 | 18–70 | |
| Gulf of Finland | 1967–1971 | 30–65 | Niemi 1975; Bagge & Niemi 1971 |
| 78 | Forsskåhl et al. 1982 | ||
| Gulf of Finland – Helsinki area | 1968 | 150–200 | Bagge & Lehmusluoto 1971 |
Country allocation of nutrient load reduction acc_ to Country Allocated Reduction Target (CART) (HELCOM 2013a,b) and regional allocation of TP load reduction acc_ to Håkanson et al_ (2010)
| Country | HELCOM (2013a,b) approach | Håkanson et al. (2010) approach | |||||
|---|---|---|---|---|---|---|---|
| CARTTN [tons yr-1] | CART TP [tons yr-1] | Percentage contribution | Region | TP [tons yr-1] | TN [tons yr-1] | ||
| TN | TP | ||||||
| Denmark | 2890 | 38 | 3.24 | 0.26 | Bothnian Sea | Not needed | Reduction not recommended by the authors |
| Germany | 7670 | 170 | 8.59 | 1.18 | |||
| Poland | 43 610 | 7480 | 48.86 | 52.04 | Bothnian Bay | Not needed | |
| Lithuania | 8970 | 1470 | 10.05 | 10.23 | |||
| Latvia | 1670 | 220 | 1.87 | 1.53 | Gulf of Finland | 3180 | |
| Estonia | 1800 | 320 | 2.02 | 2.23 | |||
| Russia | 10 380 | 3790 | 11.63 | 26.36 | Gulf of Riga | 550 | |
| Finland | 3030 | 356 | 3.39 | 2.48 | |||
| Sweden | 9240 | 530 | 10.35 | 3.69 | Baltic Proper | 5000 | |
| Sum | 89 260 | 14 374 | 100.00 | 100.00 | 8730 | ||
Annual primary production [g C m-2 yr-1] in various regions of the Baltic Sea and various periods of time (source: Renk 2000 – publication of NMFRI)
| Area | Study period | |||
|---|---|---|---|---|
| 1971–1974 | 1981–1985 | 1987–1991 | 1994–1998 | |
| Gulf of Gdańsk (average value) | 140 | 156 | ||
| Gulf of Gdańsk (Gdansk Deep) | 107 | 129 | 172 | 190 |
| Bornholm Basin (Bornholm Deep) | 82 | 91 | 123 | 164 |
| Gotland Basin (Gotland Deep) | 92 | 116 | 141 | 140 |
| Słupsk Furrow | 88 | 103 | ||
Combined flow normalized TN and TP loads discharged by the Vistula, the Oder, and the Pomeranian rivers in the reference period (1997–2003) and in 2012–2014, and the difference in loads in these two periods (yellow columns); maximum loads observed in 1992–1994 (TN) and 1988–1991 (TP), and the difference between maximum loads and those in 2012–2014 (green columns); allocation of load reduction acc_ to BSAP (HELCOM 2013b) (red column)
| Nitrogen, phosphorus loads | In 1997–2003 | In 2012–2014 | Difference between 1997–2003 and 2012–2014 | Maximal observed (years in brackets) | Difference between max. observed and 2012–2014 | BSAP Poland |
|---|---|---|---|---|---|---|
| tons yr-1 | ||||||
| TN | 169648 | 140 372 | 29 276 | 209 243 (1992–1994) | 68 871 | 43 610 |
| TP | 11 548 | 8990 | 2558 | 14 903 (1988–1991) | 5913 | 7480 |
Eutrophication indicators in the brackish water systems (salinity 5–20 PSU) for four specified trophic states (source: Nixon 1995; Håkanson & Bryhn 2008)
| Trophic state | Håkanson and Bryhn (2008) | Nixon (1995) | ||||
|---|---|---|---|---|---|---|
| Secchi depth | Chl-a | TN | TP | Cyanobacteria | Organic carbon supply | |
| m | μg l-1 | μg wm l-1 | g C m-2 yr-1 | |||
| Oligotrophic | > 8 | < 2 | < 70 | < 10 | < 9.5 | < 100 |
| Mesotrophic | 4.5–8 | 2–6 | 70–220 | 10–30 | 9.5–380 | 100–300 |
| Eutrophic | 1.5–4.5 | 6–20 | 220–650 | 30–90 | 380–2500 | 301–500 |
| Hypertrophic | < 1.5 | > 20 | > 650 | > 90 | > 2500 | > 500 |
Average combined flow normalized TN and TP loads, calculated for the reference period (1997–2003) for the Vistula and the Oder, and approximated for Polish rivers directly feeding the Baltic Sea, and target TN and TP concentrations at CART assumptions (Table 2); concentrations in brackets are offcially accepted maximum allowable values, meeting the good ecological status specified in WFD (Garcia et al_ 2012)
| Average flow normalized TN loads | Average flow normalized TP loads | Target CART and max allowable WFD concentrations TN | Target CART and max allowable WFD concentrations TP | Target CART and max allowable WFD concentrations TN | Target CART and max allowable WFD concentrations TP |
|---|---|---|---|---|---|
| Vistula + Oder + other rivers | Vist | Oder | |||
| tons N yr-1 | tons P yr-1 | mg dm-3 | |||
| 94 794 + 57 220 + 17 634 = 169 648 | 6250+4116+1182= 11 548 | 2.06 target TN concentrations could be slightly lower if we took into account the reduction of direct atmospheric deposition to the Baltic Sea by Poland; | 0.067 (0.29) | 2.57 target TN concentrations could be slightly lower if we took into account the reduction of direct atmospheric deposition to the Baltic Sea by Poland; | 0.083 (0.29) |