Myrberg, K. & Andrejev, O. 2003: Main upwelling regions in the Baltic Sea — a statistical analysis based on three-dimensional modelling. Boreal Env. Res. 8: 97–112.

In the Baltic Sea upwelling is an important process, especially in the coastal areas, causing vertical mixing and displacement of the water body. During thermal stratification, when the surface layer of the water is depleted of nutrients, upwelling plays a key role in replenishing the euphotic zone with the nutritional components necessary for biological productivity. Up to now, only a few comprehensive investigations have been carried out to study the locations of the main upwelling areas in the Baltic and how commonly these upwellings take place. Here, three-dimensional high-resolution modelling is used as a tool to statistically estimate an index reflecting the persistency of upwellings (downwellings) in various parts of the Baltic. This estimate is made for the summer season over the ten-year period from 1979 to 1988. The new idea in this paper is to use the persistency (stability) of the vertical velocity to define an upwelling index, instead of calculating the frequency of upwelling on the basis of changes in the sea-surface temperature, as is usually done. The model results were compared with measurements of surface temperature and salinity in the Gulf of Finland in 1988, where several strong upwelling cases were observed. The fit between the model results and measurements was found to be good. The upwelling indexes were compared with corresponding upwelling frequencies in the Swedish coastal area based on an analysis of long-term sea-surface temperature measurements. The results, based on these two different approaches, correspond well with each other. Consequently, we can expect that the three-dimensional model can be used to good effect as a tool to describe the overall statistics of the main upwelling areas in the Baltic. The results of the ten-year simulation show that coastal-type upwellings (downwellings) dominate, with values of the index as high as 30%–50% (–30% to –50%), being typically between 10% and 30% (–10% to –30%). The width scale of upwellings (perpendicular to the coast) is typically only 5–20 km. The length scale is somewhat more variable, being typically between 30 and 150 km (alongshore).

Klavins, M., Rodinov, V. & Druvietis, I. 2003: Aquatic chemistry and humic substances in bog lakes in Latvia. Boreal Env. Res. 8: 113–123.

Chemical composition of 19 bog lakes in Latvia has been studied. Peculiarities of chemical composition and their influence on community structure have been analysed as the main factors considering aquatic humic substances (AHS). AHS isolated from bog waters shows principally different elemental, functional and spectral characteristics, and also acidity, from humic substances isolated from other water bodies (eutrophic and mesotrophic) and reference humic samples. The observed differences are due to the dependence of humus properties on biological processes and pollution levels in the water bodies.

Karvosenoja, N. & Johansson, M. 2003: Primary particulate matter emissions and the Finnish climate strategy. Boreal Env. Res. 8: 125–133.

There is an increasing need for the assessment of particulate matter (PM) emissions of different particle sizes because of the adverse health effects of the fine size fractions. Combustion of fuels is an important source of fine primary particles and an important factor in strategies to combat climate change. In this study, a calculation system was developed for primary PM emissions from stationary combustion and their control. It was used to calculate present (1990 and 1995) and future (2010) primary PM emissions for three energy scenarios. Large energy production units already utilize very efficient particle removal equipment. Less extensive use of solid fossil fuels in studied low-CO₂ scenarios does not substantially reduce primary PM emissions. Domestic wood combustion, where no control technologies are in use, constitutes the major part of combustion-based primary PM emissions both at present and in the future, especially for the fine particle fractions. The results for 1995 were considerably higher than earlier international estimates.

Bonsdorff, E., Laine, A. O., Hänninen, J., Vuorinen, I. & Norkko, A. 2003: Zoobenthos of the outer archipelago waters (N. Baltic Sea) — the importance of local conditions for spatial distribution patterns. Boreal Env. Res. 8: 135–145.

The variability in species number and abundance of the soft-sediment benthic animal communities of the Archipelago Sea and western Gulf of Finland (SW Finland) is described in relation to environmental variables using multivariate analysis. The results show assemblages along the outer archipelago zone, facing the open sea, illustrating the importance of local conditions for the functioning of the zoobenthos. Based on clustering and multidimensional scaling of species abundance, the sampling sites formed distinct groups (benthic assemblages) linked to different geographical sub-areas. The main group, dominated by the amphipod Monoporeia affinis, was mainly found between the outer islands and skerries of the Archipelago Sea. Five additional groups were identified, which were geographically scattered and dominated either by the bivalve Macoma balthica, by M. affinis, or by oligochaetes. Based on rank correlation between the (dis)similarity matrices of species composition and environmental characteristics, the combination of dissolved oxygen saturation, temperature and sediment organic matter content best explained the species distribution and community structure of benthic fauna. The groups could also be positioned along an environmental gradient with increasing distance from the mainland, increasing depth and salinity, decreasing organic content (i.e. food availability), and declining temperature. The results are discussed in relation to environmental properties, highlighting the need for a baseline survey for future coastal monitoring, and in relation to the EC Water Framework Directive (2000/60/EC), stressing the relationship between environmental typology and biological (ecological) indicators of environmental health.

Lahdes, E. O. & Vainio, L. A. 2003: Effect of season on the acute thermal tolerance and thermal inactivation of membrane (Mg²⁺ + Na⁺ + K⁺)- and Mg²⁺-adenosine triphosphatase activity of the Baltic Sea amphipods, Monoporeia affinis and Gammarus spp.. Boreal Env. Res. 8: 147–157.

This paper presents a study of the acute upper thermal tolerance and thermal inactivation (IA50) of the membrane-bound (Mg²⁺ + Na⁺ + K⁺)- and Mg²⁺-adenosine triphosphatases of the Baltic amphipods, Monoporeia affinis, inhabiting a stable cold environment (ca. 3.5 °C), and Gammarus spp., living in annually fluctuating temperatures (0–20 °C). For M. affinis the lethal temperatures (LT50) in a continuously rising temperature were 29.8 °C in winter, 29.5 °C in spring and 30.2 °C in summer. For Gammarus spp. the LT50 was 31.0 °C in spring, 32.8 °C in summer and 30.2 °C in autumn. Seasonality in the LT50 values was observed in Gammarus spp., but in M. affinis only the summer value differed from the other seasons. The LT50 of M. affinis did not change after temperature acclimation of the animals at 13.5 °C. The thermal inactivation values (IA50) of the ATPases of M. affinis (44.3–47.4 °C) were higher than those of Gammarus spp. (40.3–45.2 °C). In Gammarus differences in the IA50 values between the seasons were found while in M. affinis only between spring and summer.

O'Brien, K., Hänninen, J., Kanerva, T., Metsärinne, L. & Vuorinen, I. 2003: Macrozoobenthic zonation in relation to major environmental factors across the Archipelago Sea, northern Baltic Sea. Boreal Env. Res. 8: 159–170.

Benthic macrofaunal assemblages from a series of samples taken between 1994 and 2000 across the Archipelago Sea are described, and community structure in relation to major environmental factors analysed. Results provided a clear division of the Archipelago Sea into three zones based on benthic species composition. Environmental factors which best explained the observed species distribution, i.e. temperature, salinity, dissolved oxygen, and sediment organic carbon were seen to operate along a cline of increasing depth. An east-west comparison of adjacent zones was also investigated. These closely resembled one another showing few significant differences. Local environmental factors were considered responsible where differences were observed. Evidence of a marked temporal difference in species composition in the middle parts of the archipelago was shown. The results, in line with ordination analysis, indicated a seawards shift of the more polluted/impacted zones. The predictive capabilities of the canonical ordination method of redundancy analysis (RDA) were discussed.

Helama, S. & Lindholm, M. 2003: Droughts and rainfall in south-eastern Finland since AD 874, inferred from Scots pine ring-widths. Boreal Env. Res. 8: 171–183.

Early summer (May–June) precipitation variability was reconstructed for south-eastern Finland using a millennia-long (from 874 to present day) ring-width chronology of Scots pine (Pinus sylvestris L.). A regression-based calibration model using tree-ring widths captured 31% of the variance in the observed precipitation record. The time stability of the reconstruction equations was studied by cross-calibration/verification. Additional verification was provided by a neighbouring weather station. Interannual variability as well as periods of abundant rainfall and drought are presented. The three most humid early summers occurred in 1090, 1094 and 1924, and the driest in 939, 943 and 1116. Prolonged periods of severe drought took place during 1173–1191, 1664–1680 and 1388–1402, and wet spells during 1081–1095, 1433–1447 and 1752–1765. Fast Fourier transform showed the most dominant cyclic behaviour on interdecadal time scales.

Kinnunen, H., Holopainen, T., Räisänen, M. L. & Kärenlampi, L. 2003: Fluoride in birch leaves, ground vegetation, litter and humus in the surroundings of a fertilizer plant and apatite mine in Siilinjärvi, eastern Finland. Boreal Env. Res. 8: 185–192.

Fluoride is one of the main emission components of the fertilizer plant and strip mine located at Siilinjärvi, in eastern Finland. The fluoride concentration of birch (Betula pendula Roth.) leaves, ground vegetation, litter layer and humus layer were determined in the surroundings of the plant and the mine to evaluate their validity as bioindicators of fluoride pollution. The highest fluoride concentrations were observed near the fertilizer plant, the strip mine or tailings impoundments in all studied materials. Highest total fluoride concentration was observed in the litter and humus layers where the fluoride has been accumulating over three decades. The fluoride concentration of both vegetation (birch leaves and ground vegetation) and soil organic horizon (litter and humus layers) can be regarded as good indicators of fluoride load but their role is quite different. Especially birch leaves, but also ground vegetation, can be used as indicators of annual or short time fluoride load and are available in repeated monitoring, whereas litter or humus layer reveal the long time accumulation of fluoride-containing fallout.