Koski, P., Soivio, A., Hartikainen, K., Hirvi, T. & Myllylä, T. 2001. M74 syndrome and thiamine in salmon broodfish and offspring. Boreal Env. Res. 6: 79–92.
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Hänninen, J. & Vuorinen, I. 2001. Macrozoobenthos structure in relation to environmental changes in the Archipelago Sea, northern Baltic Sea. Boreal Env. Res. 6: 93–105.
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Lappalainen, A., Rask, M., Koponen, H. & Vesala, S. 2001. Relative abundance, diet and growth of perch (Perca fluviatilis) and roach (Rutilus rutilus) at Tvärminne, northern Baltic Sea, in 1975 and 1997: responses to eutrophication? Boreal Env. Res. 6: 107–108.
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Salonen, V.-P., Varjo, E. & Rantala, P. 2001. Gypsum treatment in managing the internal phosphorus load from sapropelic sediments; experiments on Lake Laikkalammi, Finland. Boreal Env. Res. 6: 119–129.
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Kiirikki, M., Inkala, A., Kuosa, H., Pitkänen, H., Kuusisto, M. & Sarkkula, J. 2001. Evaluating the effects of nutrient load reductions on the biomass of toxic nitrogen-fixing cyanobacteria in the Gulf of Finland, Baltic Sea. Boreal Env. Res. 6: 131–146.
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Rankinen, K., Bärlund, I., Ahonen, J., Forsius, M. & Kämäri, J. 2001. Input uncertainty analysis of the dynamic soil model SMART2 using Monte Carlo sampling. Boreal Env. Res. 6: 147–158.
Abstract
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Koski, P., Soivio, A., Hartikainen, K., Hirvi, T. & Myllylä, T. 2001. M74 syndrome and thiamine in salmon broodfish and offspring. Boreal Env. Res. 6: 79–92.
Hänninen, J. & Vuorinen, I. 2001. Macrozoobenthos structure in relation to environmental changes in the Archipelago Sea, northern Baltic Sea. Boreal Env. Res. 6: 93–105.
Lappalainen, A., Rask, M., Koponen, H. & Vesala, S. 2001. Relative abundance, diet and growth of perch (Perca fluviatilis) and roach (Rutilus rutilus) at Tvärminne, northern Baltic Sea, in 1975 and 1997: responses to eutrophication? Boreal Env. Res. 6: 107–108.
Salonen, V.-P., Varjo, E. & Rantala, P. 2001. Gypsum treatment in managing the internal phosphorus load from sapropelic sediments; experiments on Lake Laikkalammi, Finland. Boreal Env. Res. 6: 119–129.
Kiirikki, M., Inkala, A., Kuosa, H., Pitkänen, H., Kuusisto, M. & Sarkkula, J. 2001. Evaluating the effects of nutrient load reductions on the biomass of toxic nitrogen-fixing cyanobacteria in the Gulf of Finland, Baltic Sea. Boreal Env. Res. 6: 131–146.
Rankinen, K., Bärlund, I., Ahonen, J., Forsius, M. & Kämäri, J. 2001. Input uncertainty analysis of the dynamic soil model SMART2 using Monte Carlo sampling. Boreal Env. Res. 6: 147–158.
The relationship was examined between the occurrence of M74 syndrome (abnormally high yolk-sac fry mortality in the Baltic salmon) and the thiamine (B1 vitamin) concentration in the eggs, liver and white muscle of female salmon broodfish and in the fry. Newly stripped eggs with total thiamine concentrations of ca. 0.35 mg kg–1 or lower were shown to develop into M74 offspring. M74 syndrome was not found to exist in the Teno river Atlantic salmon or in the Daugava river Baltic salmon, but was prevalent in 1994–1996 in the Finnish rivers flowing into the Gulf of Bothnia. This is thought to be a result of the low reserves of thiamine in the broodfish during maturation in these rivers. It was shown that sexual maturation of female salmon broodfish entails the transport of a large amount of thiamine to the ovaries. The total thiamine content of the liver was only a fraction of that needed in the eggs, but white muscle tissue may act as a reserve for this purpose.
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Since the 1960s, the major environmental change affecting the water quality of the Baltic Sea has been eutrophication. Several types of effects were attributed to increasing eutrophication in the benthic communities. In the present study, we describe the soft bottom benthic assemblages based on species number, abundance and biomass in the Airisto Inlet in 1994, and analyse the changes of community structure in relation to major environmental changes in the Archipelago Sea area since the 1950s. Special emphasis was put on alterations of Macoma balthica and Monoporeia affinis proportions. Our results provided evidence of a general increase of benthic macrofauna, especially in the middle and southern parts of the study area. The greatest relative increase seemed to occur to polychaetes and oligochaetes, whereas M. affinis showed the greatest absolute increase. However, the relative proportions of M. balthica and M. affinis generally remained unchanged. We conclude that, in the middle and southern parts, the changes observed in macrozoobenthos were due to general eutrophication in the Archipelago Sea. In the northern parts, the communities have been remarkably influenced by local pollution and dredging.
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The coastal waters of the northern Baltic Sea have been undergoing a progressive process of eutrophication in recent decades. Gill net samples were taken in the Tvärminne area (SW Finland) to assess the effects of coastal eutrophication on the stocks of two common species, perch (Perca fluviatilis) and roach (Rutilus rutilus). The relative abundance, diet and growth of perch were rather similar in 1975 and in 1997. However, the higher abundance of roach catches in the outer archipelago and their slower growth rate indicate that roach stocks have increased during the last 20 years. Perch feed mainly on macro-crustaceans and fish, whereas roach feed mainly on molluscs. In 1997, Saduria entomon was absent from the diet of perch, and the contribution of Mytilus edulis and Cerastoderma glaucum, two important components in the diet of roach, had decreased, possibly reflecting changes in local benthic communities. The most pronounced change, however, was the increase in local roach stocks, which was attributed to coastal eutrophication.
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The sediment of the hypertrophic Lake Laikkalammi, (area 8000 m2, max. depth 13 m) in southern Finland was treated with the industrial by-product Fe-gypsum (CaSO4 x 2H2O) in summer 1998. A 90% reduction of the hypolimnic total phosphorus content was achieved and Secchi disk transparency increased from 50 cm to 270 cm during one year long observation period. Gypsum is hypothesized to limit the internal load through three interacting mechanisms: as a mechanical cover limiting the resuspension and gas ebullition, as a chemical offering binding sites for phosphorus (Ca, Fe) and finally by changing the microbiological composition of sediment by creating more favorable conditions for sulphur bacteria instead of methane bacteria. Fe-gypsum treatment can be seen as a complementary lake restoration method that is suitable for relatively deep, small lakes in which the water quality problems are a consequence of internal loading caused by oxygen deficiency in the hypolimnion.
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The effects of nutrient load reductions on the biomass of N-fixing cyanobacteria were evaluated in the scale of the Gulf of Finland. The two analysed reduction scenarios were Finnish national agenda and the improvement of phosphorus removal in the present purification plants of St. Petersburg. The effects of load reduction scenarios were tested by using a 3D-ecosystem model with a horizontal resolution of 5 km. According to the results the Finnish national agenda cannot decrease the biomass of N-fixing cyanobacteria, but it seems to be able to reduce the total phytoplankton biomass in the coastal waters. The phosphorus reduction in St. Petersburg decreases the N-fixing cyanobacteria significantly in the central parts of the Gulf of Finland. Improvement of the phosphorus purification efficiency in the present sewage treatment plants offers us an opportunity to try to control the intensity of the toxic blooms of nitrogen-fixing cyanobacteria in the scale of the Gulf of Finland.
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A dynamic soil model SMART2 has been developed to estimate long-term chemical changes in soil and soil water in response to changes in atmospheric deposition. The aim of this study was to rank the input parameters on the basis of their contribution to model uncertainty in order to determine which additional data would best improve the reliability of predictions. The Monte Carlo technique was used in combination with regression analysis. The uncertainty study was conducted for stream water pH and NO3 concentration and for soil base saturation. Parameters defining nutrient mineralization in soil and plant uptake of nitrogen and base cations were also studied. Nitrogen uptake was mainly influenced by N concentration in stem and leaves, but also by parameters defining N mineralization in soil and N denitrification. Weathering rates and nutrient concentrations in vegetation appear to be the most important inputs explaining base saturation of mineral soil, NO3 concentration and pH of stream water.
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