ISSN 1239-6095
© Boreal Environment Research 2002

Contents of Volume 7 Number 1

Kotilainen, A.T., Hämäläinen, J.M.S. & Winterhalter, B. 2002. Reconstructing a continuous Holocene composite sedimentary record for the eastern Gotland Deep, Baltic Sea. Boreal Env. Res. 7: 1–12.
Abstract
Full text (pdf format)

Müller, A. 2002. Geochemical expressions of late- and post-glacial land–sea interactions in the southern Baltic Sea. Boreal Env. Res. 7: 13–25.
Abstract
Full text (pdf format)

Kauppila, T., Moisio, T. & Salonen, V.-P. 2002. Diatom-inferred increase in limnetic phosphorus concentration and the associated changes in sedimentary phosphorus fractions in Valkjärvi, a lake in Kärkölä, Finland. Boreal Env. Res. 7: 27–40.
Abstract
Full text (pdf format)

Vuorinen, I., Antsulevich, A.E. & Maximovich, N.V. 2002. Spatial distribution and growth of the common mussel Mytilus edulis L. in the archipelago of SW-Finland, northern Baltic Sea. Boreal Env. Res. 7: 41–52.
Abstract
Full text (pdf format)

Westman, K. & Savolainen, R. 2002. Growth of the signal crayfish, Pacifastacus leniusculus, in a small forest lake in Finland. Boreal Env. Res. 7: 53–61.
Abstract
Full text (pdf format)

Mousavi, S.K. 2002. Boreal chironomid communities and their relations to environmental factors — the impact of lake depth, size and acidity. Boreal Env. Res. 7: 63–75.
Abstract
Full text (pdf format)

Yrjänä, T., van der Meer, O., Riihimäki, J. & Sinisalmi, T. 2002. Contributions of short-term flow regulation patterns to trout habitats in a boreal river. Boreal Env. Res. 7: 77–89.
Abstract
Full text (pdf format)


Kotilainen, A.T., Hämäläinen, J.M.S. & Winterhalter, B. 2002. Reconstructing a continuous Holocene composite sedimentary record for the eastern Gotland Deep, Baltic Sea. Boreal Env. Res. 7: 1–12.

It has been generally assumed that sediments in the deepest parts of the Gotland Basin have accumulated in a relatively calm depositional environment during the entire Holocene, thus representing a continuous sedimentary record. As part of the Baltic Sea System Study (BASYS) we have had access to several long cores from the Gotland Deep, which we have investigated in detail. The study, utilising sediment physical properties (e.g., magnetic susceptibility) and lithostratigraphic (core descriptions, photographs, stereo X-ray radiographs) data, has shown that even over very short horizontal distances the sedimentary records reflect considerable variations in sediment accumulation. Definable sedimentary units show marked variation in thickness, including clear hiatuses. These indicate that environmental conditions have been far more dynamic than has been previously assumed, and that the patchy nature of sediment deposition in the Baltic Sea is characteristic also to the Gotland Deep. This is true especially of the Litorina Sea, Post-Litorina Sea and Recent Baltic Sea stages of the Baltic Sea (~ past 7500–8000 cal years BP). Due to the fact that sediment stratigraphy can change a lot even over very short distances in this deep basin, correlation between different cores should be done with great care. To produce a stratigraphically continuous sequence for the Gotland Deep, we have spliced data together from several different cores.
Back to the top

Müller, A. 2002. Geochemical expressions of late- and post-glacial land–sea interactions in the southern Baltic Sea. Boreal Env. Res. 7: 13–25.

The coastal region of the southern Baltic Sea has been extremely sensitive to sea-level changes during the Quaternary. The present environment is comprised of coastal lagoons and is characterized by Pleistocene islands connected by Holocene barrier islands. To determine the effects of late- and post-glacial coastal development on the lagoon sediments, 13 sediment cores from 6 lagoons were investigated. Organic carbon to nitrogen (Corg/N), and organic carbon to sulfur ratios (Corg/S), [delta]13C, [delta]15N, organic carbon, biogenic opal and calcium carbonate values were measured and linked to the late- and post-glacial biostratigraphy of the sediments. Although, with the exception of the Oder lagoon, the lagoons show similarities in their paleoenvironments derived from the Corg/S ratios in the sediment, it is possible to derive the influence of the Baltic Sea waters. Corg/N ratios, [delta]13C, [delta]15N, organic carbon, biogenic opal and calcium carbonate values all reflect changes in productivity over time and influence of river input, transgression and erosion. The results were used to derive the effects of sea-level changes, coastal development and related changes in hydrography and accompanying accumulation processes at the bottom of the lagoons. The results of this study show that, depending on its position to the Baltic Sea, each lagoon responded differently to sea-level changes that occurred during the development of the Baltic Sea and to regional coastal development.
Back to the top

Kauppila, T., Moisio, T. & Salonen, V.-P. 2002. Diatom-inferred increase in limnetic phosphorus concentration and the associated changes in sedimentary phosphorus fractions in Valkjärvi, a lake in Kärkölä, Finland. Boreal Env. Res. 7: 27–40.

A diatom-based total phosphorus (TP) model developed for southern Finland is used to infer past epilimnetic TP concentrations in Valkjärvi, a lake located in Kärkölä, Finland; and the results are compared with sedimentary phosphorus fractions. The diatom-based models accurately predicted epilimnetic TP concentrations as indicated by monitoring data available since 1979. Altogether, concentrations have increased from 15 ug P l–1 in the 1940s to the present level of ~65 ug P l–1. After an initial slow increase, the lake became eutrophicated rapidly in the 1960s as a result of municipal wastewater from the Kärkölä commune. These nutrient inputs resulted in increased sedimentary phosphorus concentrations. The NaOH-extracted phosphorus fraction in particular increased in the profundal sediments. The changes in sedimentary phosphorus nevertheless occurred later than the increase in diatom-inferred limnetic TP concentration.
Back to the top

Vuorinen, I., Antsulevich, A.E. & Maximovich, N.V. 2002. Spatial distribution and growth of the common mussel Mytilus edulis L. in the archipelago of SW-Finland, northern Baltic Sea. Boreal Env. Res. 7: 41–52.

Abundance, biomass, size distribution and growth of the common mussel, Mytilus edulis L. along a transect extending through the SW archipelago of Finland, northern Baltic Sea are described here for the first time. The parameters studied were found to vary according to environmental gradients extending from the inner to the outer archipelago. The lowest densities and biomass were found in the innermost archipelago. Most of the populations here consisted of small individuals between 4 to 6 mm (antero-posterior length), while in the middle and outer archipelago areas modal size was approximately twice as large. The average growth rate of mussels in the middle archipelago was higher than in all other areas. Very slow growing, or “dwarf” mussels were found in all areas studied, but these were most common in the outer archipelago.
Back to the top

Westman, K. & Savolainen, R. 2002. Growth of the signal crayfish, Pacifastacus leniusculus, in a small forest lake in Finland. Boreal Env. Res. 7: 53–61.

The growth, growth per moult and moulting frequency of adult Pacifastacus leniusculus were studied in 1975–1977 and 1987–1988 in Iso-Majajärvi, an 11 ha oligotrophic lake with a very low calcium concentration (mean 1.6 mg l–1) in central Finland (61°52'N, 23°51'E). Growth was determined from the relationship between premoult and postmoult carapace lengths (CL) and measured on marked specimens. The mean absolute per moult increment (MI) in CL was 5.3 mm (i.e. 10.6 mm in total length, TL) in males and 4.1 mm (i.e. 8.2 mm in TL) in females. The percentage moult increase (PCMI) in CL ranged from 4.7% to 20.0% in males and from 1.5% to 13.6% in females. The MI and PCMI of both sexes diminished with the increase in size. Males moulted more often than females. About 27% of adult males apparently moulted twice and 73% once. Among females, 30% moulted twice and about 70% once. Due to their rapid growth, more than half of P. leniusculus (the majority males) reached harvesting size (> 100 mm TL) at the age of 3+, by which time some were up to 115 mm (TL). Data on length/weight and carapace/total length ratios are given. The growth of adult P. leniusculus in Iso-Majajärvi was of the same order of magnitude as in two other Finnish lakes with a higher Ca concentration.
Back to the top

Mousavi, S.K. 2002. Boreal chironomid communities and their relations to environmental factors — the impact of lake depth, size and acidity. Boreal Env. Res. 7: 63–75.

The relationship between chironomid community composition and certain lake characteristics was investigated using canonical correspondence analysis (CCA) on literature-retrieved data sets from 38 localities in North America and 43 in northern Europe. Three separate analyses were performed, classifying the chironomids to subfamily, genus or species level. The results demonstrate that the occurrence and abundance of chironomids are a function of lake depth, size and acidity. The subfamily Diamesinae-Prodiamesinae was a good indicator of large deep lakes with higher pH values. Subfamily Orthocladiinae was an indicator of relatively small lakes with low pH and conductivity, while Tanytarsini occurred in lakes with relatively high pH value. Tanypodinae and in particular Chironomini appeared less influenced by the analyzed environmental factors than other chironomids. At the genus level, Ablabesmyia and Zalutschia and subgenus Psectrocladius and Monopsectrocladius dominated in small shallow lakes with low values of pH and conductivity, whereas Prodiamesa, Cryptotendipes, Thienemaniella, Paratendipes, Stempellina and Cricotopus dominated in large deep lakes with high pH. The most common chironomids, the genera Procladius, Tanytarsus and Chironomus, were less correlated with the environmental factors in the boreal lakes, although some Chironomus species appeared to be indicative of acid lakes.
Back to the top

Yrjänä, T., van der Meer, O., Riihimäki, J. & Sinisalmi, T. 2002. Contributions of short-term flow regulation patterns to trout habitats in a boreal river. Boreal Env. Res. 7: 77–89.

Physical habitat simulation modelling was used to evaluate the effects of flow regulation on the Siikajoki, a boreal river in Central Finland. In the modelling, the “natural flow” regime, the “implemented regulation” pattern and two alternative patterns of regulation were compared by using brown trout (Salmo trutta) as a test fish and by analysing example periods in winter and in summer. The availability of suitable habitats for brown trout (Weighted Usable Area, WUA) was clearly dependent on the flow rate. The fewest usable habitats were available for the size class “fry” (< 15 cm). We found only minor differences between the compared regulation patterns in terms of riverine habitats. A side channel in the test area proved to be good “buffer area” against flow changes, highlighting the importance of habitat diversity. In a sensitivity analysis of habitat modelling, modifications of the depth preference curve seemed to have a major influence on the WUA for young brown trout.
Back to the top