Tammi, J., Lappalainen, A. & Bergman, T. 2003: Water quality and fish populations of acid sensitive waters in the Vätsäri area, north-eastern Finland: responses to reduced sulphur emissions from the Kola Peninsula, Russia, in the 1990s. Boreal Env. Res. 8: 1–7.

Changes in fish population and water quality in response to the decline in sulphur deposition in small waterbodies in north-eastern Finland were studied by using data from two consecutive surveys of fish and water chemistry at 20 sampling sites in 1993 and in 2000. The study area consisted of three separate catchment basins near the Norwegian–Russian border area, 40–50 km west of the nearest large source of SO₂, the Nikel industrial complex in the Kola Peninsula. The most common fish species caught were minnow (Phoxinus phoxinus), burbot (Lota lota) and brown trout (Salmo trutta). Special attention was focused on minnow because of its sensitivity to acidification and its frequent occurrence in the study area. At all sampling sites, the alkalinity values of the sampled brooks and lakes were significantly higher and the sulphate concentrations significantly lower in 2000 than in 1993. The increased densities of minnow and changes in the length distribution of the sampled fish indicated that reproduction of the species was successful at most of the sampling sites in the late 1990s. The results suggest that the decrease in acid emissions from the Kola industrial centres has resulted in noticeable chemical and biological recovery of the most acid-sensitive surface waters in north-eastern Finnish Lapland.

Knapp, C.W., Graham, D.W., Steedman, R.J. & deNoyelles, F. Jr. 2003: Deep chlorophyll maxima in small boreal forest lakes after experimental catchment and shoreline logging. Boreal Env. Res. 8: 9–18.

In situ profiles of chlorophyll fluorescence combined with depth-specific water chemistry and biotic analysis were used to assess deep chlorophyll maxima (DCM) in four boreal shield lakes that were subjected to different levels of watershed disturbance by clear-cut logging. Phytoplankton communities within the DCM varied among lakes, but were generally comprised of chrysophytes, diatoms, and cryptophytes. One lake also had deep cyanobacterial populations. Relative in situ fluorescence (absolute fluorescence at each peak minus background fluorescence) at the fluorescence peaks was significantly correlated with the level of chlorophyll a at the peak (r² = 0.81, p < 0.025) for all lakes. In general, DCM peak heights were consistent in each lake over the four-year post-logging sampling period, whereas DCM depths declined slightly in the most heavily logged lakes associated with increases in dissolved organic carbon. Therefore, on the basis of DCM data, only mild effects on lake water quality were apparent after the logging activity.

Haapala, A., Muotka, T. & Laasonen, P. 2003: Distribution of benthic macroinvertebrates and leaf litter in relation to streambed retentivity: implications for headwater stream restoration. Boreal Env. Res. 8: 19–30.

The distribution of leaf litter and benthic macroinvertebrates was studied in two boreal streams: a stream with a natural streambed (Merenoja), a channelized stream (Rutajoki), and the latter stream after its restoration. Leaf release experiments were performed to characterise the retentive structures of each stream. Benthic samples were collected from patches that retained artificial leaves (`retention sites') and from randomly located patches (`random sites'). Retention sites contained significantly more benthic leaves than random sites in each stream, but the difference between patch types was most distinct in the channelized stream. Densities of shredders and other detritivores were distinctly higher in retention than in random sites in Rutajoki, both before and after restoration. In Merenoja, shredders were evenly distributed among the patch types. Restoration clearly increased the trapping efficiency of Rutajoki, but only slightly reduced the aggregation of detritivores to retentive stream patches. Our study highlights the importance of detritus aggregations for stream invertebrates, especially in channelized streams.

Siimes, K. & Kämäri, J. 2003: A review of available pesticide leaching models: Selection of models for simulation of herbicide fate in Finnish sugar beet cultivation. Boreal Env. Res. 8: 31–51.

The quality of simulation results depends on the model structure and its parameterisation. The aim of this study was to find the best available models for herbicide fate simulation for Finnish conditions. Subjective model selection criteria were developed for the simulation domain: pesticide fate in Finnish sugar beet cultivation. An inventory was made of available models and a number of different pesticide and solute transport models were identified. Thirteen one-dimensional deterministic models (CRACK-NP, EPIC, GLEAMS, LEACHP, MACRO, OPUS, PELMO, PEARL, PESTLA, PLM, PRZM, RZWQM and SIMULAT) were compared and evaluated for their characteristics. The comparison showed that none of these models fulfilled all of the desired criteria. Finally, MACRO 4.1 and GLEAMS 3.0 were selected for herbicide fate simulations. The other high regarded models were RZWQM, PEARL and PELMO.

Nieminen, M. 2003: Effects of clear-cutting and site preparation on water quality from a drained Scots pine mire in southern Finland. Boreal Env. Res. 8: 53–59.

Ditch outflow from four treatment areas on a drained Scots pine mire was sampled for one year before and four years after clear-cutting and different site preparation operations. Ditch-mounding, or excavation of 40–60 cm deep ditches at spacings of 12–15 m in connection with mounding, is currently considered the most reliable site preparation method for drained peatlands in Finland. High leaching rates of suspended solids were detected from the ditch-mounding area, where the ditches reached down into the mineral soil below peat layer. In contrast to clear-cutting + mounding (without ditches) and clear-cutting alone, cutting and ditch-mounding also increased the leaching of ammonium and nitrate. Phosphorus concentrations in ditch outflow following clear-cutting and site preparation increased from areas where peat contents of phosphorus sorbing minerals (aluminium and iron) were low. The study demonstrated that clear-cutting and site preparation can significantly impair water quality from drained low productive pine mires.

Vuori, K.-M., Siren, O. & Luotonen, H. 2003: Metal contamination of streams in relation to catchment silvicultural practices: a comparative study in Finnish and Russian headwaters. Boreal Env. Res. 8: 61–70.

We studied metal contamination of streams in the forestry dominated and close-on pristine subcatchments in Finland and Russian Karelia. In this area, atmospheric deposition and point loading are insignificant as sources of metals, while geochemical sources and silvicultural activities are important. Aquatic moss Fontinalis antipyretica Hedw. was used as a sentinel organism measuring the metal contamination. Tufts of Fontinalis were collected at 10 Russian and 8 Finnish stream sites for the measurement of whole-plant Al, Fe, Cd, Zn, Cu, Pb and Ni concentrations. The average Al, Fe, Cd, Cu, Zn and Ni concentrations were statistically significantly higher in the Finnish moss samples than in the Russian ones. In particular, concentrations of Al, Fe, Cu, Ni and Zn in many Finnish streams clearly exceeded natural background concentrations and were comparable to the earlier results from streams affected by metal loading from point and non-point sources. The results suggest that silvicultural practices in combination with specific geochemical features may cause metal contamination of streams in areas considered otherwise unpolluted. We stress the importance of taking precautions against forestry-induced metal contamination.

Venäläinen, A., Sahlgren, V., Podsechin, V. & Huttula, T. 2003: Small-scale variability of the wind field over a typical Scandinavian lake. Boreal Env. Res. 8: 71–81.

Lake flow and transport models are largely dependent on the accuracy of the input data like wind forcing. In the current study the WAsP (Wind Atlas Analysis and Application Program) model was used for the calculation of wind conditions on a typical north European lake, lake Längelmävesi-Roine. Lake is relatively small and landscape fragmented. The main objective was to estimate how well the measurement made at one location represented conditions in different parts of the lake. It was found that, due to the influence of orography and surface roughness, the mean wind speed values could at certain locations be about 30% weaker than those at the measurement site. The variation in mean wind direction was small. The results of the study demonstrate that models like WAsP can provide valuable and substantial information and thus the use of wind models can improve the quality of lake model calculations.

Ruoho-Airola, T., Alaviippola, B., Salminen, K. & Varjoranta, R. 2003: An investigation of base cation deposition in Finland. Boreal Env. Res. 8: 83–95.

The deposition of the base cations Na⁺, K⁺, Ca²⁺ and Mg²⁺ in 1998 was estimated for Finland using measurement data for precipitation and air quality. The highest deposition for all compounds was measured near the southern coast, and it decreased gradually northwards. Deposition of sodium and magnesium increased again in the far north in the vicinity of the Arctic Ocean. The estimated ranges for the annual deposition of sodium, magnesium, potassium and calcium in Finland were 90–610 mg m^–2, 10–80 mg m^–2, 30–160 mg m^–2 and 30–210 mg m^–2, respectively. Similar values have been published for large areas of Sweden and Norway. During the last decade the sum of the base cation concentration in bulk precipitation decreased by 15%–35% in all areas in Finland. The non-sea-salt fraction declined in bulk precipitation approximately as much. An especially large reduction occurred in the southeastern part of Finland, where the wet deposition of base cations decreased almost as much as the wet deposition of sulphur.