Taskinen A. & Söderholm K. 2016: Operational correction of daily precipitation measurements in Finland. Boreal Env. Res. 21: 1–24.
Abstract
Full text (pdf format)

Johansson M.M. & Kahma K.K. 2016: On the statistical relationship between the geostrophic wind and sea level variations in the Baltic Sea. Boreal Env. Res. 21: 25–43.
Abstract
Full text (pdf format)

Enmar L., Lake I., Lundberg P. & Sigray P. 2016: A note on ADCP-based indirect observations of turbulence. Boreal Env. Res. 21: 44–52.
Abstract
Full text (pdf format)

Räsänen A., Kuitunen M., Hjort J., Vaso A., Kuitunen T. & Lensu A. 2016: The role of landscape, topography, and geodiversity in explaining vascular plant species richness in a fragmented landscape. Boreal Env. Res. 21: 53–70.
Abstract
Full text (pdf format)

Dufour B., Boucher J.-F., Tremblay P., Mailly D. & Lord D. 2016: Black-spruce–lichen woodlands growth and carbon drawdown potentials as revealed by mature stands. Boreal Env. Res. 21: 71–86.
Abstract
Full text (pdf format)

Honkonen O. & Rantalainen A.-L. 2016: Transport of urban-derived organic contaminants into a boreal lake: a case study with passive samplers. Boreal Env. Res. 21: 87–100.
Abstract
Full text (pdf format)

Voutilainen A., Jurvelius J., Lilja J., Viljanen M. & Rahkola-Sorsa M. 2016: Associating spatial patterns of zooplankton abundance with water temperature, depth, planktivorous fish and chlorophyll. Boreal Env. Res. 21: 101–114.
Abstract
Full text (pdf format)

Górniak D., Marszałek H., Jankowska K. & Dunalska J. 2016: Bacterial community succession in an Arctic lake–stream system (Brattegg Valley, SW Spitsbergen). Boreal Env. Res. 21: 115–133.
Abstract
Full text (pdf format)

Lindroos A.-J., Tamminen P., Heikkinen J. & Ilvesniemi H. 2016: Effect of clear-cutting and the amount of logging residue on chemical composition of percolation water in spruce stands on glaciofluvial sandy soils in southern Finland. Boreal Env. Res. 21: 134–148.
Abstract
Full text (pdf format)

Makkonen S., Huuhilo K., Utriainen J., Holopainen T. & Kainulainen P. 2016: Radial ring width and wood structure in the ozone-exposed Norway spruce seedlings grown under different nitrogen regimes. Boreal Env. Res. 21: 149–165.
Abstract
Full text (pdf format)

Gonzales-Inca C.A., Lepistö A. & Huttula T. 2016: Trend detection in water-quality and load time-series from agricultural catchments of Yläneenjoki and Pyhäjoki, SW Finland. Boreal Env. Res. 21: 166–180.
Abstract
Full text (pdf format)

Taskinen A. & Söderholm K. 2016: Operational correction of daily precipitation measurements in Finland. Boreal Env. Res. 21: 1–24.

An operational method for daily precipitation observation correction of aerodynamic, wetting and evaporation errors is presented. The aerodynamic correction method used has been developed for Finnish conditions when wind observations at the gauge are not available but the data from the nearest synoptic station can be used. Daily precipitation observations in Finland and its cross-boundary watersheds from the period 1961–2011 were corrected. It was discovered that the mean annual total sum of all gauges increased by 13.6% from 590.3 mm to 670.6 mm. The average overall proportions were 8.6%, 22.8% and 68.6% for evaporation, wetting and aerodynamic corrections, respectively. On a daily basis, the correction factor varied remarkably according to the form and intensity of precipitation, the median value being 1.21. Positive linear trends were identified in observed, corrected total and liquid precipitation, whereas a negative linear trend was obtained in corrected solid precipitation. The preliminary assessment using a watershed model indicated that the amount of correction is approximately correct for liquid precipitation but might slightly be too large for solid precipitation. Using corrected precipitation as a hydrological model input is recommended but a more comprehensive research is needed.

Johansson M.M. & Kahma K.K. 2016: On the statistical relationship between the geostrophic wind and sea level variations in the Baltic Sea. Boreal Env. Res. 21: 25–43.

The relationship between the Baltic Sea levels and the geostrophic wind was analysed using observations covering the entire Baltic Sea from the early 20th century to the present. A well-defined location in the southern Baltic Sea was found where the zonal geostrophic wind correlated best (r = 0.5–0.8) with the detrended monthly mean sea levels everywhere along the Baltic Sea except in the southwestern part. The sea levels also correlated with the wind of the previous month (r = 0.4–0.6). This partly delayed correlation is due to the mechanism by which the atmosphere affects sea levels: a combination of water transport in the Danish Straits, and direct effects of wind and air pressure inside the Baltic Sea basin. An estimate was calculated for the detrended variation in the water volume of the Baltic Sea. The simple regression model based on the zonal geostrophic wind explained 75% of the detrended variation in the water volume. The variation correlated well (r = 0.995) with monthly mean sea levels at F&oulm;gl&oulm; in the Âland Islands.

Enmar L., Lake I., Lundberg P. & Sigray P. 2016: A note on ADCP-based indirect observations of turbulence. Boreal Env. Res. 21: 44–52.

A 70-day data set from bottom-mounted ADCPs on the two sides of the Faroe-Bank Channel was analysed using the recorded flow variance and echo intensity in the deeper reaches of the passage as proxies for turbulence. A consistent picture emerged, not least since the data losses (which were ascribed to turbulence-induced activation of the fish-elimination option in the ADCP software) could be shown to co-vary with the internal M₂ tide affecting the vertical shear, which in turn proved to be correlated with the flow variance.

Räsänen A., Kuitunen M., Hjort J., Vaso A., Kuitunen T. & Lensu A. 2016: The role of landscape, topography, and geodiversity in explaining vascular plant species richness in a fragmented landscape. Boreal Env. Res. 21: 53–70.

We explained vascular plant species richness patterns in a 286 km² fragmented landscape with a notable human influence. The objective of this study was two-fold: to test the relative importance of landscape, topography and geodiversity measures, and to compare three different landscape-type variables in species richness modeling. Moreover, we tested if results differ when only native species are considered. We used generalized linear modeling based variation partitioning and generalized additive models with different explanatory variable sets. Landscape and topography explained the majority of the variation but the relative importance of topography and geodiversity was higher in explaining native species richness than in explaining total species richness. Differences between the three landscape type variables were small and they provided complementary information. Finally, topography and geodiversity often direct human action and can be ultimate causes behind both landscape variability and species richness patterns.

Dufour B., Boucher J.-F., Tremblay P., Mailly D. & Lord D. 2016: Black-spruce–lichen woodlands growth and carbon drawdown potentials as revealed by mature stands. Boreal Env. Res. 21: 71–86.

The afforestation of widely distributed boreal open woodlands such as lichen woodlands (LWs) could provide both a restoration of the closed-crown forest structure in the boreal forest and a mitigation measure against global warming. By comparing natural, mature stands of LW with their dense counterparts — black-spruce–feathermoss stands as a plantation surrogate — this study aims to validate the long-term LW growth support capacity for a high tree density and their carbon sequestration potential after afforestation. Our results reveal that the site potential of LWs can be either lower or equivalent to that of dense stands. This finding contradicts the paradigm of systematic lower tree growth in LWs. The site potential of LWs can be assessed by dominant tree volume at 50 years. This study also shows that the CBM-CFS3 model can simulate the conservative net carbon balance of afforested LW, and, as such, can help reduce uncertainties regarding the long-term net carbon drawdown of afforested LWs.

Honkonen O. & Rantalainen A.-L. 2016: Transport of urban-derived organic contaminants into a boreal lake: a case study with passive samplers. Boreal Env. Res. 21: 87–100.

The aim of this study was to evaluate the sources, transport and distribution of hydrophobic organic contaminants produced in an urban area. Passive sampling devices (PSDs) were employed in the storm-water drainage of the city of Lahti, in an adjacent boreal lake (Vesijärvi) and along its shore. Samples were analysed for 16 polycyclic aromatic hydrocarbons (PAHs) and 28 polychlorinated biphenyls (PCBs) with a gas chromatograph–mass spectrometer. Concentrations of contaminants were elevated in the stormwater drainage and in the vicinity of the stormwater outlets in Vesijärvi, but declined as a function of distance from the shore. Atmospheric PAH concentrations were significantly higher in the autumn than in the summer. Petrogenic PAHs contributed significantly to stormwater contamination, while pyrogenic pollutants mainly appeared to be carried to Vesijärvi by atmospheric transport.

Voutilainen A., Jurvelius J., Lilja J., Viljanen M. & Rahkola-Sorsa M. 2016: Associating spatial patterns of zooplankton abundance with water temperature, depth, planktivorous fish and chlorophyll. Boreal Env. Res. 21: 101–114.

The spatial distribution of zooplankton was studied in a boreal lake system. Distribution patterns were associated with water temperature and depth, abundance of fish, and chlorophyll-a concentration. Principal coordinates of neighbor matrices (PCNM) were used to model spatial structures (vectors between study locations) which were in turn used in regression models to explain plankton distribution. Data were also analyzed using detrended correspondence analysis (DCA). Models based on PCNM highlighted differences between sites, whereas DCA emphasized differences between the epi-, meta- and hypolimnion. Bottom-up regulation was the primary force in determining zooplankton and fish abundance. Signs of top-down regulation were also found. The main forces driving spatial heterogeneity of zooplankton in lakes differed among thermal strata and among zooplankton size categories and species. The study stressed the need for gathering data with more than one method simultaneously and emphasized the benefits of combining results from two or more statistical techniques.

Górniak D., Marszałek H., Jankowska K. & Dunalska J. 2016: Bacterial community succession in an Arctic lake–stream system (Brattegg Valley, SW Spitsbergen). Boreal Env. Res. 21: 115–133.

The factors affecting prokaryotic and virus structure dynamics and bacterial community composition (BCC) in aquatic habitats along a ca. 1500 m of the Brattegg Valley lake–stream system (SW Spitsbergen) composed of three postglacial lakes created by Brattegg Glacier meltwater were examined. A high number of small-volume prokaryotic cells were found in the recently-formed, deep, upper, subglacial lake. Bacterial taxonomic diversity assessed by PCR-DGGE indicated that the lakes? BCC differed; with its richness decreasing down the system. Fluorescence in situ hybridisation (FISH) revealed a BCC increase; mainly in α-Proteobacteria, Cytophaga/Flavobacterium and Actinobacteria. We found increasing β-Proteobacteria and Actinobacteria numbers and a decrease in α-Proteobacteria down the system. Our results indicate that glacial meltwater sustains an active bacterial community which is then stimulated or partly eliminated by the proglacial lakes? higher temperature and nutrient input. We conclude that the prokaryotic succession along this lake–stream system occurs through changes in the structure of dominant bacterial communities, their replacement and elimination.

Lindroos A.-J., Tamminen P., Heikkinen J. & Ilvesniemi H. 2016: Effect of clear-cutting and the amount of logging residue on chemical composition of percolation water in spruce stands on glaciofluvial sandy soils in southern Finland. Boreal Env. Res. 21: 134–148.

The relationship between the amount of logging residue and element leaching from forest ecosystems to watercourses is not fully understood. We hypothesized that if the amount of logging residue in slash piles increases, this will be reflected as elevated N, DOC, base cation and PO₄-P concentrations in soil percolation water after clear-cut of spruce stands at site types with homogenous sandy material. Percolation water (depth 40 cm) was collected from small experimental sample plots by soil column lysimeters at two sites. The treatments were 0, 10 and 40 kg m^–2 of logging residue. The highest NO₃-N concentrations (mean > 15 mg l^–1) were associated with the highest amount of logging residue left at the site. The NO₃-N concentrations were < 1 mg l^–1 in the third year after clear-cut in the treatments 0 and 10 kg m^–2 of logging residue. DON, DOC and PO₄ did not leach markedly, but higher base cation concentrations were associated with the highest amount of logging residue.

Makkonen S., Huuhilo K., Utriainen J., Holopainen T. & Kainulainen P. 2016: Radial ring width and wood structure in the ozone-exposed Norway spruce seedlings grown under different nitrogen regimes. Boreal Env. Res. 21: 149–165.

Norway spruce seedlings were exposed to two ozone levels (ambient and 1.5–1.6 x ambient) at moderate (optimum N), low (70% of optimum N), and high soil-nitrogen availability (150% of optimum N), in an open-air exposure field for two growing seasons. Radial ring width and wood structure in the stem were investigated from the seedlings. The seedlings grown under elevated O₃ showed an increase in radial width of growth ring built during the first exposure season. Elevated O₃ increased latewood width, its proportion within the growth rings being most pronounced in low N treated trees, whereas higher N mitigated latewood production. High soil N increased earlywood width and resulted in an increased lumen area and lower cell-wall/cell-lumen ratio of tracheids within earlywood and latewood. Ozone had no effect on earlywood width or the lumen area or cell wall/ cell lumen ratio in juvenile wood. High latewood percentage in O₃-exposed seedlings implies earlier transition from earlywood to latewood or longer period of latewood formation.

Gonzales-Inca C.A., Lepistö A. & Huttula T. 2016: Trend detection in water-quality and load time-series from agricultural catchments of Yläneenjoki and Pyhäjoki, SW Finland. Boreal Env. Res. 21: 166–180.

Long-term water quality (WQ) and load trends were studied in the catchments of Yläneenjoki and Pyhäjoki in SW Finland, where agricultural water protection measures have been implemented since the mid-1990s. A univariate Mann-Kendall (MK) trend test, a multivariate Mann-Kendall (MMK) trend test, and a multivariate Mann-Kendall trend test applied to the WQ data flow-normalized by a semi-parametric model (FN-MMK) were used. The results of all methods were similar when the nutrient concentration data were used, but they differed when using the nutrient load data. The FN-MMK test was intended to detect trends caused by anthropogenic impact. In the clay-soil-dominated catchment of Yläneenjoki there were increasing trends in the concentrations and loads of total nitrogen, nitrate-nitrogen, dissolved reactive phosphorus, and a decreasing trend in suspended solid concentrations. However, no increasing or decreasing trends were detected for the majority of the concentrations or loads in sand-soil-dominated catchment of Pyhäjoki. This suggests different responses to comparable environmental and anthropogenic pressures in these two river basins.