BER 16 (3), 2011

ISSN 1239-6095 (print), ISSN 1797-2469 (online)
© Boreal Environment Research 2011

Contents of Volume 16 Number 3

Yekta, S. S. & Rahm, L. 2011: A model study of the effects of sulfide-oxidizing bacteria (Beggiatoa spp.) on phosphorus retention processes in hypoxic sediments: Implications for phosphorus management in the Baltic Sea. Boreal Env. Res. 16: 167–184.
Abstract
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Alahuhta, J., Vuori, K.-M. & Luoto, M. 2011: Land use, geomorphology and climate as environmental determinants of emergent aquatic macrophytes in boreal catchments. Boreal Env. Res. 16: 185–202.
Abstract
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Saue, T. & Kadaja, J. 2011: Possible effects of climate change on potato crops in Estonia. Boreal Env. Res. 16: 203–217.
Abstract
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Selkimäki, M. & Mola-Yudego, B. 2011: Estimating and modelling the resistance of nature to path erosion in Koli National Park, Finland. Boreal Env. Res.16: 218–228.
Abstract
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Lankinen, P., Kähkönen, M. A., Rajasärkkä, J., Virta, M. & Hatakka, A. 2011: The effect of nickel contamination on the growth of litter-decomposing fungi, extracellular enzyme activities and toxicity in soil. Boreal Env. Res. 16: 229–239.
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Lindroos, A.-J., Derome, J., Derome, K. & Smolander, A. 2011: The effect of Scots pine, Norway spruce and silver birch on the chemical composition of stand throughfall and upper soil percolation water in northern Finland. Boreal Env. Res. 16: 240–250.
Abstract
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Ongoing eutrophication increases phosphorus storage in surficial sediments of the Baltic Sea which can then be released during hypoxic/anoxic events. Such sediments are suitable habitats for sulfide-oxidizing bacteria, Beggiatoa spp. The objective of this paper is to investigate the effects of these bacteria on the P retention processes in hypoxic sediments using a diagenetic model. This model simulates interactions of the processes controlling P mobility in the sediments with redox reactions from the Beggiatoa metabolism. Modeling results demonstrate that P retention capability is limited when dissolved iron is mineralized as iron sulfides in the sediments. In this regard, sulfide consumption by Beggiatoa spp. potentially decreases the rate of iron sulfide formation and consequently increases the P retention capability in local-scale sediment.

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We studied the distribution patterns of emergent aquatic macrophytes in relation to land use, geomorphology and climate variables throughout Finland, using data collected from 848 catchments. Our results confirmed previous findings on climatic factors as major determinants of macrophyte distribution, but also catchment land-use, especially drainage ditch intensity, appear to be significant. Drainage ditch intensity had equal or higher contribution to emergent aquatic macrophytes as compared with that of geomorphology variables. To our knowledge this is the first analysis to show that ditch intensity increases emergent aquatic macrophytes at the national level. Overall, our results demonstrate that neither overgrowth problems nor natural distribution patterns of emergent aquatic macrophytes can be understood without analyzing the joint effects of land use, climate and geomorphology.

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Saue, T. & Kadaja, J. 2011: Possible effects of climate change on potato crops in Estonia. Boreal Env. Res. 16: 203–217.

The main objective of this research is to generate and analyse values of meteorologically possible yields (MPY, maximum yield achievable under given meteorological conditions) of potato for the middle and the end of the 21st century, at three Estonian locations. An early and a late potato varieties are analysed as examples. Climate change is evaluated under four different emission scenarios by 18 different GCMs; resultant changes are introduced into a dynamical potato growth model POMOD. The climate-driven changes without considering the effect of CO₂ concentration change are determined. A negative impact of climate warming on early potato growth in Estonia is confirmed. Moderate climate change scenarios will have a positive influence on growth of the late potato variety, whereas stronger changes will cause the decline of agrometeorological resources. A more positive or less negative effect of climate change is detected for northern Estonia.

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Selkimäki, M. & Mola-Yudego, B. 2011: Estimating and modelling the resistance of nature to path erosion in Koli National Park, Finland. Boreal Env. Res. 16: 218–228.

We studied the resistance of nature to trampling and path erosion in Koli National Park. The data are based on 201 field measurements of paths together with digital datasets in order to identify the main factors affecting path erosion. Additionally, the resistance of different forest types to trampling was studied. Models for path erosion were constructed in order to predict the width and depth of a path. Slope of the path and the number of visitors were the two main factors explaining width and depth. The lowest resistance areas were identified in rocky-site forest located on the hilltops, while the deepest paths were on moraine soils. Paths on meadows were highly resistant to trampling and the most resistance forest type was Oxalis–Myrtillus. The results of this study can be applied in national park management and can be the basis for the design of measures to reduce path erosion. By mapping the most sensitive areas, the path network can be planned to be sustainable. Recreational pressure can be redirected to more resistant areas or structures such as duckboard and stairs can be built to protect the most sensitive areas. Developed models can be used for testing where to place new paths in order to minimize path erosion.

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A multi-phased approach was used to assess microbial function and the growth of litter-decomposing fungi in the Ni-contaminated organic layer of a young Pinus sylvestris forest in southern Finland. Eight fungi tested (Agaricus bisporus, Agrocybe praecox, Gymnopus peronatus, Gymnopilus sapineus, Mycena galericulata, Gymnopilus luteofolius, Stropharia aeruginosa and Stropharia rugosoannulata) were able to grow in the Ni-contaminated soil (20 mg [kg soil]^–1). β-glucosidase, β-cellobiosidase, phosphomonoesterase, acetate-esterase and butyrate-esterase activities were mainly lower in the Ni-contaminated soil than in the non-contaminated soil. Low concentration of Ni (20 mg l^–1) inhibited the growth of all fungi on humus, RBBR and ABTS containing agar colour plates. EC₅₀ for light inhibition in a test involving the yeast Saccharomyces cerevisiae was 294 mg Ni l^–1, which was quite high when compared with the inhibition of fungal growth on colour plates (20 mg Ni l^–1) and the EC₅₀ for light inhibition of the bacterium Vibrio fischeri (85 mg Ni l^–1). Low Ni concentrations (20 mg [kg soil]^–1) in the present study inhibited microbial activity, the growth and enzyme production of litter-decomposing fungi.

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The aim of this study was to determine the effect of pine (Pinus sylvestris), spruce (Picea abies) and birch (Betula pendula) on the chemical composition of stand throughfall (TF), percolation water (PW) and forest soil in northern Finland. The order of the tree species as regards the pH was approximately the same in both the soil and PW samples: birch > spruce > pine (O horizon), birch > spruce = pine (E horizon). Tree species did not have a notable effect on the DOC concentrations in PW. The base saturation and the Ca and Mg concentrations were the highest in the birch stand. The total Al concentration in PW was mainly related to the concentration of organic Al complexes in all the stands. The total and organically complexed Al concentration was its smallest at a depth of 10 cm in the spruce stand. Whether the properties of DOC present under spruce are the reason for the smaller formation of organic Al complexes in the spruce stand requires further research.

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