BS2 Nitrogen
MQ is a measure of average water discharge (cubic metres per second). Water discharge is monitored in a more than 280 observation stations in Finland. The observations are gathered as daily averages.
Nutrient concentrations for the Gulf of Finland have been calculated as an average data of four observation sites (Huovari, Haapasaari, Länsi-Tonttu and Längden). Gulf of Bothnia also include four observation sites (LAV4, Hailuoto, Vavy19 and Vav11). The concentrations for Archipelago Sea are results of only one site, Seili. Data from all observation sites have not necessarily been available for every year.
A) Nitrogen load to the Baltic Sea carried by rivers
| Year | Total nitrogen (t/a) |
MQ (m3/s) |
Year | Total nitrogen (t/a) |
MQ (m3/s) |
|
| 1970 | 56 440 |
2 069 |
1991 | 75 230 |
2 804 |
|
| 1971 | 49 380 |
2 331 |
1992 | 88 800 |
3 470 |
|
| 1972 | 60 220 |
2 435 |
1993 | 60 200 |
2 856 |
|
| 1973 | 51 920 |
2 454 |
1994 | 53 000 |
2 363 |
|
| 1974 | 90 200 |
3 453 |
1995 | 61 300 |
2 822 |
|
| 1975 | 57 540 |
2 729 |
1996 | 57 400 |
2 325 |
|
| 1976 | 50 170 |
1 779 |
1997 | 59 800 |
2 394 |
|
| 1977 | 83 740 |
3 098 |
1998 | 84 900 |
3 411 |
|
| 1978 | 47 660 |
2 017 |
1999 | 64 400 |
2 658 |
|
| 1979 | 62 890 |
2 567 |
2000 | 99 480 |
3 439 |
|
| 1980 | 54 750 |
2 241 |
2001 | 72 270 |
2 707 |
|
| 1981 | 91 730 |
3 819 |
2002 | 47 470 |
2 097 |
|
| 1982 | 74 460 |
2 983 |
2003 | 48 410 |
1 763 |
|
| 1983 | 60 650 |
2 828 |
2004 | 81 010 |
2 987 |
|
| 1984 | 78 790 |
3 125 |
2005 | 77 070 |
2 957 |
|
| 1985 | 58 360 |
2 686 |
2006 | 77 370 |
2 412 |
|
| 1986 | 72 800 |
2 821 |
2007 | 79 170 |
2 987 |
|
| 1987 | 66 480 |
2 998 |
2008 | 97 640 |
3 667 |
|
| 1988 | 72 490 |
2 862 |
2009 | 48 280 |
2 279 |
|
| 1989 | 73 670 |
3 044 |
2010 | 58 500 |
2 509 |
|
| 1990 | 65 130 |
2 355 |
2011 | 80 420 |
2 781 |
B) Nitrogen concentration in surface water
| Year | Gulf of Finland |
Gulf of Bothnia |
Archipelago Sea |
Year | Gulf of Finland |
Gulf of Bothnia |
Archipelago Sea |
|
| 1968 | 1991 | 195.4 |
134.3 |
209.0 |
||||
| 1969 | 100.0 |
1992 | 194.7 |
125.0 |
173.3 |
|||
| 1970 | 191.0 |
1993 | 190.8 |
155.9 |
239.3 |
|||
| 1971 | 176.5 |
1994 | 192.0 |
122.6 |
157.1 |
|||
| 1972 | 124.0 |
1995 | 168.6 |
135.1 |
178.4 |
|||
| 1973 | 72.0 |
1996 | 170.3 |
102.4 |
104.3 |
|||
| 1974 | 56.5 |
1997 | 137.2 |
113.9 |
149.6 |
|||
| 1975 | 1998 | 138.9 |
135.0 |
172.5 |
||||
| 1976 | 1999 | 163.3 |
139.7 |
197.3 |
||||
| 1977 | 114.7 |
2000 | 136.4 |
132.0 |
262.4 |
|||
| 1978 | 109.3 |
2001 | 176.8 |
150.1 |
181.1 |
|||
| 1979 | 164.6 |
97.0 |
2002 | 122.3 |
139.7 |
164.0 |
||
| 1980 | 182.1 |
127.3 |
2003 | 181.0 |
108.9 |
119.8 |
||
| 1981 | 173.3 |
119.8 |
2004 | 138.0 |
115.4 |
209.0 |
||
| 1982 | 206.5 |
147.3 |
2005 | 131.3 |
162.7 |
234.9 |
||
| 1983 | 189.5 |
159.1 |
297.5 |
2006 | 155.5 |
124.5 |
170.6 |
|
| 1984 | 189.7 |
109.8 |
184.0 |
2007 | 164.8 |
193.6 |
249.0 |
|
| 1985 | 233.9 |
122.6 |
178.0 |
2008 | 122.7 |
118.8 |
224.8 |
|
| 1986 | 230.0 |
128.4 |
262.0 |
2009 | 161.3 |
129.5 |
141.5 |
|
| 1987 | 222.3 |
128.3 |
211.0 |
2010 | 228.0 |
109.0 |
120.4 |
|
| 1988 | 206.6 |
149.6 |
202.3 |
2011 | 144.8 |
122.5 |
124.0 |
|
| 1989 | 171.9 |
120.4 |
127.1 |
2012 | 189.9 |
133.1 |
202.8 |
|
| 1990 | 230.1 |
168.7 |
198.4 |
Links:
Nutrient pollution and eutrophication (Helsinki Comission)
Eutrophication (The Baltic Sea Portal)
References: