ISSN 1239-6095
© Boreal Environment Research 2003

Contents of Volume 8 Number 3

Häkkinen, J., Korhonen, H., Oikari, A. & Karjalainen, J. 2003: Melanin concentrations in vendace (Coregonus albula) and whitefish (Coregonus lavaretus) larvae from five boreal lakes with different optical properties. Boreal Env. Res. 8: 193–201.
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Koponen, K., Huuskonen, S., Ritola, O., Venäläinen, R., Tarhanen, J. & Lindström-Seppä, P. 2003: Muscle chemical content and hepatic biotransformation in bream (Abramis brama) and asp (Aspius aspius) in a PCB-contaminated lake. Boreal Env. Res. 8: 203–213.
Abstract
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Miettinen, J. O. 2003: A diatom-total phosphorus transfer function for freshwater lakes in southeastern Finland, including cross-validation with independent test lakes. Boreal Env. Res. 8: 215–228.
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Autio, L., Mäkelä, K., Lehtonen, K. K., Kuparinen, J. & Haahti, H. 2003: Effects of algal sedimentation and Monoporeia affinis on nutrient fluxes, pore water profiles and denitrification in sediment microcosms. Boreal Env. Res. 8: 229–243.
Abstract
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Tuittila, E.-S., Vasander, H. & Laine, J. 2003: Success of re-introduced Sphagnum in a cut-away peatland. Boreal Env. Res. 8: 245–250.
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Zhang, Y., Pulliainen, J., Koponen, S. & Hallikainen, M. 2003: Empirical algorithms for Secchi disk depth using optical and microwave remote sensing data from the Gulf of Finland and the Archipelago Sea. Boreal Env. Res. 8: 251–261.
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Rossini Oliva, S. & Raitio, H. 2003: Review of cleaning techniques and their effects on the chemical composition of foliar samples. Boreal Env. Res. 8: 263–272.
Abstract
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Häkkinen, J., Korhonen, H., Oikari, A. & Karjalainen, J. 2003: Melanin concentrations in vendace (Coregonus albula) and whitefish (Coregonus lavaretus) larvae from five boreal lakes with different optical properties. Boreal Env. Res. 8: 193–201.

The objective was to investigate correlation between melanin concentration in fish larvae and the optical properties of water in five study lakes. Melanin concentration was analyzed from vendace and whitefish larvae; sampled in May from lakes with different UV attenuation depth, water colour and transparency. Overall, vendace exhibited more pigmentation than whitefish. In both species larval pigmentation correlated positively with water colour, but the correlation was negative with UV-B attenuation depth. Based on our results, it is evident that ambient UV-B was insufficient to modify the degree of melanin pigmentation of coregonid fish larvae in Finnish lakes. We suggest that the main reason for the observed difference in larval melanin concentrations between lakes is that larvae adapt to the background colour, possibly to reduce visual predation.
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Koponen, K., Huuskonen, S., Ritola, O., Venäläinen, R., Tarhanen, J. & Lindström-Seppä, P. 2003: Muscle chemical content and hepatic biotransformation in bream (Abramis brama) and asp (Aspius aspius) in a PCB-contaminated lake. Boreal Env. Res. 8: 203–213.

During the period of 1956–1983, an approximated amount of 900 liters of polychlorinated biphenyls (PCBs) was discharged into a small freshwater lake in southern Finland. Biomonitoring study of the lake in 1998 revealed clearly detectable muscle PCB concentrations in the two feral fish species studied, bream (Abramis brama) and asp (Aspius aspius), suggesting persistent PCB contamination in the lake. The muscle PCB contents in bream and asp were 18 and 59 times higher than the corresponding values measured in reference locations. The hepatic monooxygenase EROD activities were significantly induced in fish caught from the lake, underlining the biomarker value of EROD measurements in monitoring long-term chemical exposure in field studies. The conjugation GST activities showed mostly seasonal differences and did not indicate the chemical stress of fish.
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Miettinen, J. O. 2003: A diatom-total phosphorus transfer function for freshwater lakes in southeastern Finland, including cross-validation with independent test lakes. Boreal Env. Res. 8: 215–228.

A diatom total phosphorus (TP) training set and weighted averaging (WA) calibration model for lakes in eastern and southeastern Finland are presented. The data set comprises 78 lakes, with autumnal TP-range of 3–125 ug l–1, pH-range of 5.9–7.7, and lake area of 0.13–283 km2. The correlation between the observed and WA-reconstructed (jackknifed) log TP values in the training set is 0.86 (R2 = 0.73), and root mean squared error of prediction (RMSEp) 0.193 ug TP l–1. The transfer function was cross-validated using an independent test set of 30 lakes. The correlation between the observed and predicted log TP values for the 30 lakes is 0.89 (R2 = 0.79), and RMSEp 0.161 ug TP l–1. These performance statistics (R2, RMSEp), based on the independent cross-validation with the test set of lakes, are within the range of values based on jackknifing estimates, suggesting that diatoms provide reliable estimates of lakewater TP concentration in Finnish lakes.
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Autio, L., Mäkelä, K., Lehtonen, K. K., Kuparinen, J. & Haahti, H. 2003: Effects of algal sedimentation and Monoporeia affinis on nutrient fluxes, pore water profiles and denitrification in sediment microcosms. Boreal Env. Res. 8: 229–243.

A flow-through experiment was conducted to study the effects of a simulated algal sedimentation (8.0 g C m-2) and the amphipod Monoporeia affinis (5000 ind. m-2) using well-oxidised sediment from the Gulf of Bothnia. Pore water nutrient profiles, nutrient fluxes, sediment denitrification and O2 consumption as well as NH4+ excretion of M. affinis were followed for 7 days. After the algal enrichment, the NO3- concentration fell to near zero in the pore water and a decrease in the denitrification rate was observed. This occurred since the concentration of NO3- in the flow-through water was low and coupled nitrification-denitrification formed the main denitrification pathway. The share of denitrification compared to other loss processes of N from the sediment reduced from 37% in the control cores to 0.7% in the algae treated cores. The efflux of NH4+ from the sediment formed 99% of the total loss of N in the algae treated cores. A massive efflux of NH4+ and PO43- was observed after the algal enrichment. The amphipods did not increase denitrification.
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Tuittila, E.-S., Vasander, H. & Laine, J. 2003: Success of re-introduced Sphagnum in a cut-away peatland. Boreal Env. Res. 8: 245–250.

In a four-year field experiment, we studied the establishment success of re-introduced Sphagnum angustifolium in a restored (rewetted) cut-away peatland. The importance of (1) the presence of capitula and (2) water table level for re-colonisation was tested. The ten times greater cover produced by moss material with capitula revealed that using only the top few centimetres of moss surface the re-colonisation success can be remarkably accelerated. Each year the mean cover was higher in drier conditions than in the regularly flooded conditions. Similarly the length of mosses increased more evenly in drier conditions. The weaker establishment at wetter conditions was a result of peat erosion and the disappearance of mosses due to periodical flooding. The development of Sphagnum carpet was not linear but the cover decreased during years with periods of flooding and drought. The dynamic state of the Sphagnum surfaces showed that the moss cover was not permanently established during the four years study period, but was sensitive to variation in water table level.
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Zhang, Y., Pulliainen, J., Koponen, S. & Hallikainen, M. 2003: Empirical algorithms for Secchi disk depth using optical and microwave remote sensing data from the Gulf of Finland and the Archipelago Sea. Boreal Env. Res. 8: 251–261.

In this paper empirical algorithms for determining the Secchi disk depth (SDD) are developed and employed using optical (e.g., Landsat TM) and microwave (e.g., ERS-2 SAR) remote sensing data from the Gulf of Finland and the Archipelago Sea. The SDD is an important optical measure of water quality in the study area, where the coastal water considerably attenuates light because of the presence of phytoplankton, suspended matter and yellow substance. The results show that the accuracy of SDD estimation using a neural network-based method is much higher than that of a semi-empirical or multivariate approach. On the other hand, the additional use of SAR data only slightly improved SDD estimation when compared with the use of TM data only. Although the improvement is marginal, the results suggest that there may be some SAR backscattering signatures correlated to SDD measurements in the area. However, such a small improvement is not very helpful for the practical estimation of SDD. In the future, the technique of using combined optical and microwave data still needs to be refined using, e.g., MERIS and ASAR data.
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Rossini Oliva, S. & Raitio, H. 2003: Review of cleaning techniques and their effects on the chemical composition of foliar samples. Boreal Env. Res. 8: 263–272.

Chemical foliar analysis is a tool widely used to study tree nutrition and to monitor the impact and extent of air pollutants. This paper reviews a number of cleaning methods, and the effects of cleaning on foliar chemistry. Cleaning may include mechanical techniques such as the use of dry or moistened tissues, shaking, blowing, and brushing, or use various washing techniques with water or other solvents. Owing to the diversity of plant species, tissue differences, etc., there is no standard procedure for all kinds of samples. Analysis of uncleaned leaves is considered a good method for assessing the degree of air contamination because it provides an estimate of the element content of the deposits on leaf surfaces or when the analysis is aimed at the investigation of transfer of elements along the food chain. Sample cleaning is recommended in order (1) to investigate the transfer rate of chemical elements from soil to plants, (2) to qualify the washoff of dry deposition from foliage and (3) to separate superficially absorbed and biomass-incorporated elements. Since there is not a standard cleaning procedure for all kinds of samples and aims, it is advised to conduct a pilot study in order to be able to establish a cleaning procedure to provide reliable foliar data.
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