ISSN 1239-6095 (print),   ISSN 1797-2469 (online)
© Boreal Environment Research 2010

Contents of Volume 15 Number 5

Myrberg, K., Ryabchenko, V., Isaev, A., Vankevich, R., Andrejev, O., Bendtsen, J., Erichsen, A., Funkquist, L., Inkala, A., Neelov, I., Rasmus, K., Rodriguez Medina, M., Raudsepp, U., Passenko, J., Söderkvist, J., Sokolov, A., Kuosa, H., Anderson, T. R., Lehmann, A. & Skogen, M. D. 2010: Validation of three-dimensional hydrodynamic models of the Gulf of Finland. Boreal Env. Res. 15: 453–479.
Abstract
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Nyberg, K., Vuorenmaa, J., Tammi, J., Nummi, P., Väänänen, V.-M., Mannio, J. & Rask, M. 2010: Re-establishment of perch in three lakes recovering from acidification: rapid growth associated with abundant food resources. Boreal Env. Res. 15: 480–490.
Abstract
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Korsu, K., Huusko, A. & Muotka, A. 2010: Impacts of invasive stream salmonids on native fish: using meta-analysis to summarize four decades of research. Boreal Env. Res. 15: 491–500.
Abstract
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Rooney, G. G. & Jones, I. D. 2010: Coupling the 1-D lake model FLake to the community land-surface model JULES. Boreal Env. Res. 15: 501–512.
Abstract
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Aurela, M., Sillanpää, M., Pennanen, A., Mäkelä, T., Laakia, J., Tolonen-Kivimäki, O., Saarnio, K., Yli-Tuomi, T., Aalto, P., Salonen, I., Pakkanen, T., Salonen, R. O. & Hillamo, R. 2010: Characterization of urban particulate matter for a health-related study in southern Finland. Boreal Env. Res. 15: 513–532.
Abstract
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Myrberg, K., Ryabchenko, V., Isaev, A., Vankevich, R., Andrejev, O., Bendtsen, J., Erichsen, A., Funkquist, L., Inkala, A., Neelov, I., Rasmus, K., Rodriguez Medina, M., Raudsepp, U., Passenko, J., Söderkvist, J., Sokolov, A., Kuosa, H., Anderson, T. R., Lehmann, A. & Skogen, M. D. 2010: Validation of three-dimensional hydrodynamic models of the Gulf of Finland. Boreal Env. Res. 15: 453–479.

A model-intercomparison study was conducted, the first of its kind for the Baltic Sea, whose aim was to systematically simulate the basic three-dimensional hydrographic properties of a realistic, complex basin. Simulations of the hydrographic features of the Gulf of Finland for the summer–autumn of 1996 by six three-dimensional hydrodynamic models were compared. Validation was undertaken using more than 300 vertical hydrographic profiles of salinity and temperature. The analysis of model performance, including averaging of the ensemble results, was undertaken with a view to assessing the potential suitability of the models in reproducing the physics of the Baltic Sea accurately enough to serve as a basis for accurate simulations of biogeochemistry once ecosystem models are incorporated. The performance of the models was generally satisfactory. Nevertheless, all the models had some difficulties in correctly simulating vertical profiles of temperature and salinity, and hence mixed layer dynamics, particularly in the eastern Gulf of Finland. Results emphasized the need for high resolution in both vertical and horizontal directions in order to resolve the complex dynamics and bathymetry of the Baltic Sea. Future work needs to consider the choice of mixing and advection schemes, moving to higher resolution, high-frequency forcing, and the accurate representation of river discharges and boundary conditions.
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Nyberg, K., Vuorenmaa, J., Tammi, J., Nummi, P., Väänänen, V.-M., Mannio, J. & Rask, M. 2010: Re-establishment of perch in three lakes recovering from acidification: rapid growth associated with abundant food resources. Boreal Env. Res. 15: 480–490.

In 2002, we reintroduced perch (Perca fluviatilis) into three small, previously heavily acidified and fishless lakes. Test fishing indicated that released perch had survived in all three study lakes and reproduced successfully in two of them. Growth of introduced individuals had increased sharply after introduction. The increased growth of perch was an apparent consequence of high abundance of macroinvertebrates in the fishless lakes. Activity traps indicated even a 90% decrease in the numbers and size of invertebrates upon the fish releases: a very likely response to the predation by the stocked perch. Our observations indicate that the chemical recovery of the study lakes from acidification has been remarkable enough to allow recolonization by aquatic organisms. For perch, and probably for other acid tolerant fish, this means the possibility of a successful re-establishment of populations in previously acidified fishless lakes which, in turn, increases the value of such lakes for fishing.
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Korsu, K., Huusko, A. & Muotka, A. 2010: Impacts of invasive stream salmonids on native fish: using meta-analysis to summarize four decades of research. Boreal Env. Res. 15: 491–500.

Salmonid fishes are among the most frequently introduced organisms. We included 58 papers to meta-analysis to assess the effects of introduced stream salmonids on native salmonids. We also explored whether the responses of native species depended on the type of study. Introduced salmonids had negative effects on the foraging rate, abundance and survival of native salmonids, which also altered their habitat use in the presence of invaders. Brown trout appeared to be the ‘worst’ alien species (strongest impact on native fish). Negative effects were most pronounced when several introduced species were present. Moreover, the magnitude of the impact was related to the study type: the observed impacts were stronger in laboratory streams than in field enclosures or in natural streams. Our results indicate that introduced salmonid species may have little effect on native fish in some areas, but may have substantial effects in other parts of their range.
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Rooney, G. G. & Jones, I. D. 2010: Coupling the 1-D lake model FLake to the community land-surface model JULES. Boreal Env. Res. 15: 501–512.

Results are presented from the merging of the lake model FLake into the community land-surface model JULES. It is shown, by comparison with observational data, that the combined JULES-FLake model performs more realistically than JULES with its original or upgraded parametrizations for inland water. Tests against observations from lakes in the UK and Sweden show that JULES-FLake gives results for both midlatitude and arctic lakes which are comparable to the original lake model, FLake. The accuracy of JULES-FLake as a general model of the land surface is therefore enhanced. Differences in sign of the model errors in the prediction of lake-ice thickness indicate possible future directions for development and testing of these models.
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Aurela, M., Sillanpää, M., Pennanen, A., Mäkelä, T., Laakia, J., Tolonen-Kivimäki, O., Saarnio, K., Yli-Tuomi, T., Aalto, P., Salonen, I., Pakkanen, T., Salonen, R. O. & Hillamo, R. 2010: Characterization of urban particulate matter for a health-related study in southern Finland. Boreal Env. Res. 15: 513–532.

Particulate matter was physically and chemically characterized in November 2005–May 2006 concurrently with an epidemiological study among cardiac patients in Kotka, Finland. The daily PM2.5 concentrations (campaign mean 10.6 g m–3) typically displayed a similar pattern to that in Helsinki, suggesting that the air masses were well-mixed over a large area of southern Finland. There were occasionally increased short-term PM2.5 and particle number concentrations, most likely due to emissions from local industrial sources. A strong relationship was detected between high particle number concentrations (> 30 000 cm–3) and north-easterly winds. PM2.5, black carbon (BC) or nitrogen oxides (NOx) did not show corresponding connection. The mean contribution of local traffic to BC and NOx were estimated at 30% and 55%, respectively, during the campaign. The main chemical component of PM2.5 was particulate organic matter (37% ± 14%) followed by non-sea-salt sulphate (26% ± 11%), whereas main component of PM2.5–10 was soil-derived crustal material (49% ± 11%).
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