ISSN 1239-6095 (print),   ISSN 1797-2469 (online)
© Boreal Environment Research 2009

Contents of Volume 14 Number 3

Liikanen, A., Silvennoinen, H., Karvo, A., Rantakokko, P. & Martikainen, P. J. 2009: Methane and nitrous oxide fluxes in two coastal wetlands in the northeastern Gulf of Bothnia, Baltic Sea. Boreal Env. Res. 14: 351–368.
Abstract
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Seppänen, E., Piironen, J. & Huuskonen, H. 2009: Standard metabolic rate, growth rate and smolting of the juveniles in three Atlantic salmon stocks. Boreal Env. Res. 14: 369–381.
Abstract
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Nieminen, J. K. 2009: Are spruce boles hot spots for enchytraeids in clear-cut areas? Boreal Env. Res. 14: 382–388.
Abstract
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Brom, J. & Pokorny, J. 2009: Temperature and humidity characteristics of two willow stands, a peaty meadow and a drained pasture and their impact on landscape functioning. Boreal Env. Res. 14: 389–403.
Abstract
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Berezina, N. A., Zhakova, L. V., Zaporozhets, N. V. & Panov, V. E. 2009: Key role of the amphipod Gmelinoides fasciatus in reed beds of Lake Ladoga. Boreal Env. Res. 14: 404–414.
Abstract
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Sipelgas, L., Ossipova, V., Raudsepp, U. & Lindfors, A. 2009: A bio-optical model for the calculation of suspended matter concentration from MODIS data in the Pakri Bay, the Gulf of Finland. Boreal Env. Res. 14: 415–426.
Abstract
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Lehto, J. 2009: Americium in the Finnish environment. Boreal Env. Res. 14: 427–437.
Abstract
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Liikanen, A., Silvennoinen, H., Karvo, A., Rantakokko, P. & Martikainen, P. J. 2009: Methane and nitrous oxide fluxes in two coastal wetlands in the northeastern Gulf of Bothnia, Baltic Sea. Boreal Env. Res. 14: 351–368.

Fluxes of CH4 and N2O were measured in wetlands in Liminganlahti (Baltic Sea) in the vicinity of the estuaries of the Lumijoki and Temmesjoki. Wetlands were significant sources of CH4, with a mean flux of 206 mg m–2 d–1. Methane fluxes correlated positively with temperature and were slightly higher from the wetland of the Lumijoki, where water SO42– concentrations were lower. On average, the wetland close to the Temmesjoki was a small source of N2O (mean flux of 131 µg m–2 d–1), whereas the wetland close to the Lumijoki was a small sink for N2O (mean flux of –53 µg m–2 d–1). The higher availability of nitrogen in the wetland near the Temmesjoki obviously induced the higher N2O fluxes. Estuarine wetlands seem to be important sources of atmospheric CH4 but do not represent an important source of N2O although increased N loading.
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Seppänen, E., Piironen, J. & Huuskonen, H. 2009: Standard metabolic rate, growth rate and smolting of the juveniles in three Atlantic salmon stocks. Boreal Env. Res. 14: 369–381.

We examined oxygen consumption and growth rates of juveniles in three Finnish Atlantic salmon (Salmo salar) stocks (Neva, Saimaa, Teno) reared at the same fish farm. The measurements were carried out four times: in winter 2005, early spring 2006, autumn 2006 and late spring 2007 using fish hatched in February 2005, and the size and temperature ranges were wide. The salmon stocks differed in their geographical origin and native habitat presumably selecting for differences in physiological parameters. The southernmost Neva stock had higher values of a relative standard metabolic rate (rSMR) at the yolk-sac stage than the Teno stock, and the northernmost Teno stock had a higher growth rate (SGR) values at the smolt stage than the two other stocks. In addition, the stocks differed in physiological parameters characteristic of smolting: the post-smolts in the northernmost Teno stock had significantly higher rSMR and SGR, and lower condition factor values than the ones in the two other stocks.
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Nieminen, J. K. 2009: Are spruce boles hot spots for enchytraeids in clear-cut areas? Boreal Env. Res. 14: 382–388.

I investigated the effects of stem wood on enchytraeid abundance and size distribution in a Norway spruce forest after clear-cutting. Eighteen plots (16 m2) were prepared and planted with Norway spruce according to normal forestry practice and pieces of logs discarded by the logging machine were returned to nine plots. Six years after the clear-cutting enchytraeid abundance was significantly lower at 10 cm distance from added spruce boles than next to the boles and than in the control plots. Enchytraeids were significantly smaller in control plots than in wood plots and in an adjacent forest. Wood addition significantly decreased the biomass of ground vegetation six years after the clear-cutting, possibly because wood-decomposing fungi immobilized soil nutrients. Because enchytraeids feed on both fungal hyphae and plant litter, the beneficial effect of more fungal resources was counteracted by a lesser amount of grass litter in the vicinity of spruce boles.
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Brom, J. & Pokorny, J. 2009: Temperature and humidity characteristics of two willow stands, a peaty meadow and a drained pasture and their impact on landscape functioning. Boreal Env. Res. 14: 389–403.

Shrubs and herbal wetland stands have a very important influence on microclimatic conditions and short water cycling. However, they have received very little attention. This study concerns with the role of willow and peaty meadow stands and a mesic pasture in their ability to affect both the temperature and energy regime. Our results showed that the pattern of daily temperatures (diurnal variation and temperature amplitudes) were more balanced in the wetland stands than in the pasture. The most attenuated and stable temperatures were measured in the willow stands whereas the fastest warming of the soil substrate occurred in the peat meadow. Temperature amplitudes and differences in daily average temperatures on the stand surfaces increased with decreasing air humidity. Thermographic camera pictures showed that in the peaty meadow the means of stand surface temperatures as well as daily temperature oscillations were higher than in the willow stand. Although no significant statistical differences were found, daily time series of the Bowen ratio showed an increase towards midday in the willow stand. This was presumably the result of a midday depression of transpiration. We determined that more solar energy was converted into latent heat than into sensible heat in both wetland stands. Therefore we suggest that these wetland stands function in the landscape as functional dissipative ecological units.
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Berezina, N. A., Zhakova, L. V., Zaporozhets, N. V. & Panov, V. E. 2009: Key role of the amphipod Gmelinoides fasciatus in reed beds of Lake Ladoga. Boreal Env. Res. 14: 404–414.

The Baikalian amphipod Gmelinoides fasciatus, a successful invader in Eurasia, colonized the coastal zone of Lake Ladoga (northeastern Europe) in late 1990s. In the summers of 2000 and 2005 the density and biomass of benthic communities associated with macrophyte beds (Phragmites australis) and role of the invader in fish diet were studied. Due to high production of macrophytes (600–800 g carbon m–2 y–1) the benthic biomass was high, averaging 70.6 g m–2 in 2005. Whilst the mean benthic biomass showed a 2-fold increase from 1990 to 2005, the biomass of native benthos 2-fold decreased, from 33.6 ± 6.6 to 16.5 ± 6.5 g m–2. Gmelinoides fasciatus reached 54 ± 13 g m–2 and constituted 77% in the zoobenthic biomass in 2005 as compared with 6% in 1990. Some crustaceans such as Gammarus lacustris and Asellus aquaticus reduced notably their distribution area and decreased in density. G. fasciatus is an important food item in diet of ruffe, perch and young burbot.
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Sipelgas, L., Ossipova, V., Raudsepp, U. & Lindfors, A. 2009: A bio-optical model for the calculation of suspended matter concentration from MODIS data in the Pakri Bay, the Gulf of Finland. Boreal Env. Res. 14: 415–426.

A semi empirical bio-optical model was developed for the Pakri Bay. Model input parameters i.e. particle-specific spectral absorption and scattering coefficients and slope factor of coloured dissolved organic matter were calculated from the field data. The modelled reflectance spectra correspond to typical reflectance spectra with low chlorophyll-a concentration. The model is intended for the calculation of suspended matter (SM) concentration maps in the Pakri Bay using the MODIS band 1 reflectance values as input to the model. The linear relationship between the measured reflectance at the MODIS band 1 and the model reflectance was established (R = 0.76, p < 0.01, n = 48), which was used for the correction of the MODIS reflectance values. The spatial distributions of SM concentration in the Pakri Bay were calculated in four ways: (1) using bio-optical model with the MODIS reflectance values with correction; (2) using linear regression between the MODIS reflectance and SM concentration; (3) using bio-optical model with the MODIS reflectance values without correction; (4) using bio-optical model with the MODIS reflectance values with correction, but increasing chlorophyll-a concentration by two orders of magnitude as compared with that in cases 2 and 3. The first two cases produced similar results for SM concentrations, while the latter two gave much higher SM concentrations, especially in the sediment plume. It was concluded that the MODIS band 1 (620–670 nm) is the most suitable for the detection of SM concentrations between 0 and 28 mg l–1.
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Lehto, J. 2009: Americium in the Finnish environment. Boreal Env. Res. 14: 427–437.

This paper reviews studies on environmental americium, 241Am, in Finland. There are two sources of americium in the Finnish environment: fallouts from nuclear weapons tests in the 1950s and 1960s and from the Chernobyl accident in 1986, the former constituting around 98% of the total environmental load. The weapons test fallout was distributed more or less uniformly over Finland, while the Chernobyl fallout was deposited on a sector from southwestern coast to northeast. The total deposition of 241Am in Finland is approximately 20 Bq m–2 and the amount is still somewhat increasing due to decay of 241Pu. In this paper, the distribution and migration of americium in forest and aquatic environments is described. Americium concentrations in natural waters, sediments, soils, vegetation and fishes are given. In addition, the behaviour of americium in the food chain from lichen via reindeer into man is discussed. Radiation doses to humans due to the environmental americium in Finland are of no practical importance.
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