Journal articles: 'Bothnian Sea'

1

Neumann, Thomas, Herbert Siegel, Matthias Moros, Monika Gerth, Madline Kniebusch, and Daniel Heydebreck. "Ventilation of the northern Baltic Sea." Ocean Science 16, no. 4 (July 3, 2020): 767–80. http://dx.doi.org/10.5194/os-16-767-2020.

Full text

Abstract:

Abstract. The Baltic Sea is a semi-enclosed, brackish water sea in northern Europe. The deep basins of the central Baltic Sea regularly show hypoxic conditions. In contrast, the northern parts of the Baltic Sea, the Bothnian Sea and Bothnian Bay, are well oxygenated. Lateral inflows or a ventilation due to convection are possible mechanisms for high oxygen concentrations in the deep water of the northern Baltic Sea. In March 2017, conductivity–temperature–depth (CTD) profiles and bottle samples, ice core samples, and brine were collected in the Bothnian Bay. In addition to hydrographic standard parameters, light absorption has been measured in all samples. A complementary numerical model simulation provides quantitative estimates of the spread of newly formed bottom water. The model uses passive and age tracers to identify and trace different water masses. Observations indicate a recent ventilation of the deep bottom water at one of the observed stations. The analysis of observations and model simulations shows that the Bothnian Bay is ventilated by dense water formed due to mixing of Bothnian Sea and Bothnian Bay surface water initializing lateral inflows. The observations show the beginning of the inflow and the model simulation demonstrates the further northward spreading of bottom water. These events occur during wintertime when the water temperature is low. Brine rejected during ice formation barely contributes to dense bottom water.

APA, Harvard, Vancouver, ISO, and other styles

2

Mäntyniemi, Samu, Atso Romakkaniemi, Johan Dannewitz, Stefan Palm, Tapani Pakarinen, Henni Pulkkinen, Anna Gårdmark, and Olle Karlsson. "Both predation and feeding opportunities may explain changes in survival of Baltic salmon post-smolts." ICES Journal of Marine Science 69, no. 9 (May 15, 2012): 1574–79. http://dx.doi.org/10.1093/icesjms/fss088.

Full text

Abstract:

Abstract Mäntyniemi, S., Romakkaniemi, A., Dannewitz, J., Palm, S., Pakarinen, T., Pulkkinen, H., Gårdmark, A., and Karlsson, O. 2012. Both predation and feeding opportunities may explain changes in survival of Baltic salmon post-smolts. – ICES Journal of Marine Science, 69: 1574–1579. The survival of wild and hatchery-reared post-smolts of salmon (Salmo salar) in the Baltic Sea has declined since the 1990s. Direct observations of the processes affecting survival are, however, lacking. Here, the importance of food availability and predation in regulating post-smolt survival is analysed. Based on previous studies, the following explanatory variables were selected: (i) availability of herring (Clupea harengus membras) recruits in the Gulf of Bothnia (Bothnian Sea, Bothnian Bay) in the northern Baltic Sea; (ii) sprat (Sprattus sprattus balticus) and herring abundance in the southern Baltic Sea; and (iii) abundance of grey seal (Halichoerus grypus) along the post-smolt migration route. Bayesian analysis was used to estimate the relative probability of each of the 32 combinations of these variables and revealed that the model including grey seal abundance and herring recruits per post-smolt had the highest posterior probability and a high coefficient of determination. The results suggest that the declining trend in post-smolt survival is explained by the increased number of grey seals, whereas the annual variation in survival coincides with variation in the recruitment of Bothnian Sea herring. However, it remains uncertain whether the observed correlations arise from direct causalities or other mechanisms.

APA, Harvard, Vancouver, ISO, and other styles

3

Kallio-Nyberg, Irma, Heikki Peltonen, and Hannu Rita. "Effects of stock-specific and environmental factors on the feeding migration of Atlantic salmon (Salmo salar) in the Baltic Sea." Canadian Journal of Fisheries and Aquatic Sciences 56, no. 5 (May 1, 1999): 853–61. http://dx.doi.org/10.1139/f99-022.

Full text

Abstract:

Atlantic salmon (Salmo salar L.) stocks in the Baltic Sea are mainly exploited during their sea migration. The offshore fishery in the feeding grounds of these salmon permitted us to analyse the migrations of certain stocks on the basis of tag recovery data. Four salmon stocks from rivers draining into Bothnian Bay (25°E, 65.5°N) were selected for study. During 1984-1991, about 135 000 2-year-old hatchery-reared smolts were tagged and released. We applied logit models, with the site of recovery as a multicategory response variable, to analyse the distribution of tag recoveries in the Baltic Sea feeding grounds. The results showed the combined influence of stock, prey abundance, and smolt size on the spatial marine distribution of the salmon. Although stock-specific sea migration patterns were apparent, annual environmental factors had a stronger influence on the sea migration route of salmon than did the stock factor. The salmon released as small smolts (total length [Formula: see text] 17.0 cm) were more frequently caught farther from the release site than were those released as larger smolts (>17 cm). The abundance of suitable prey (age 0+ herring) in the year of smolt release was found to be a key factor influencing the migration distance. The salmon released in the years of strong herring recruitment in the Gulf of Bothnia had a higher probability to stay in the Bothnian Sea for feeding and not to migrate farther south.

APA, Harvard, Vancouver, ISO, and other styles

4

Rajasilta, M., J. Hänninen, and I. Vuorinen. "Decreasing salinity improves the feeding conditions of the Baltic herring (Clupea harengus membras) during spring in the Bothnian Sea, northern Baltic." ICES Journal of Marine Science 71, no. 5 (April 2, 2014): 1148–52. http://dx.doi.org/10.1093/icesjms/fsu047.

Full text

Abstract:

Abstract The stomach contents of the herring (Clupea harengus membras L.) from the Bothnian Sea, northern Baltic, were analysed during spring 2011 and 2013. The stomachs were full of Limnocalanus macrurus in May and June, and an improvement in the condition of herring was observed when fish started to feed on this prey. The analyses showed that Limnocalanus is currently an important link between lower trophic levels and Baltic herring in the Bothnian Sea.

APA, Harvard, Vancouver, ISO, and other styles

5

Gelting, J., E. Breitbarth, B. Stolpe, M. Hassellöv, and J. Ingri. "Fractionation of iron species and iron isotopes in the Baltic Sea euphotic zone." Biogeosciences Discussions 6, no. 4 (July 2, 2009): 6491–537. http://dx.doi.org/10.5194/bgd-6-6491-2009.

Full text

Abstract:

Abstract. Measurements of the physiochemical speciation of Fe in the euphotic zone were performed at three different locations, over a well defined salinity gradient, during spring and summer in the Baltic Sea. The average of total Fe changed from 114 nM in the Bothnian Sea, 44 nM at Landsort Deep and 15 nM at Gotland Deep. Particulate Fe (PFe) was the dominating phase at all stations and on average accounted for 75–85% of the total Fe pool. At all three locations, a decrease in total Fe of 80–90% from initial measurements compared to the summer was found. A strong positive correlation between PFe and chl-a was observed. Hence, primary production strongly regulates cycling of suspended Fe. However, this relation is not dominated by active uptake of Fe in phytoplankton; instead this reflects cycling of phosphorus, growth of diatoms, and removal of PFe during phytoplankton sedimentation. The average colloidal iron fraction, CFe, showed decreasing concentrations along the salinity gradient; Bothnian Sea 15 nM; Landsort Deep 1 nM and Gotland Deep 0.5 nM. Field Flow Fractionation data indicate that the main colloidal carrier phase for Fe in the Baltic Sea is a carbon-rich fulvic acid associated compound, likely of riverine origin. The Fe isotope composition (δ56Fe) of the PFe showed constant positive values in the Bothnian Sea surface waters (+0.08 to +0.20‰). Enrichment of heavy Fe in the Bothnian Sea PFe is most likely associated to input of aggregated land derived Fe-oxyhydroxides and a rapid overturn of Fe(II). At the Landsort deep, the fractionation of PFe changed between −0.08‰ to +0.28‰. The negative values, in early spring, probably indicate exchange over the oxic-anoxic boundary at ~80 m depth.

APA, Harvard, Vancouver, ISO, and other styles

6

Gelting, J., E. Breitbarth, B. Stolpe, M. Hassellöv, and J. Ingri. "Fractionation of iron species and iron isotopes in the Baltic Sea euphotic zone." Biogeosciences 7, no. 8 (August 23, 2010): 2489–508. http://dx.doi.org/10.5194/bg-7-2489-2010.

Full text

Abstract:

Abstract. To indentify sources and transport mechanisms of iron in a coastal marine environment, we conducted measurements of the physiochemical speciation of Fe in the euphotic zone at three different locations in the Baltic Sea. In addition to sampling across a salinity gradient, we conducted this study over the spring and summer season. Moving from the riverine input characterized low salinity Bothnian Sea, via the Landsort Deep near Stockholm, towards the Gotland Deep in the Baltic Proper, total Fe concentrations averaged 114, 44, and 15 nM, respectively. At all three locations, a decrease in total Fe of 80–90% from early spring to summer was observed. Particulate Fe (PFe) was the dominating phase at all stations and accounted for 75–85% of the total Fe pool on average. The Fe isotope composition (δ 56Fe) of the PFe showed constant positive values in the Bothnian Sea surface waters (+0.08 to +0.20‰). Enrichment of heavy Fe in the Bothnian Sea PFe is possibly associated to input of aggregated land derived Fe-oxyhydroxides and oxidation of dissolved Fe(II). At the Landsort Deep the isotopic fractionation of PFe changed between −0.08‰ to +0.28‰ over the sampling period. The negative values in early spring indicate transport of PFe from the oxic-anoxic boundary at ∼80 m depth. The average colloidal iron fraction (CFe) showed decreasing concentrations along the salinity gradient; Bothnian Sea 15 nM; Landsort Deep 1 nM, and Gotland Deep 0.5 nM. Field Flow Fractionation data indicate that the main colloidal carrier phase for Fe in the Baltic Sea is a carbon-rich fulvic acid associated compound, likely of riverine origin. A strong positive correlation between PFe and chl-a indicates that cycling of suspended Fe is at least partially controlled by primary production. However, this relationship may not be dominated by active uptake of Fe into phytoplankton, but instead may reflect scavenging and removal of PFe during phytoplankton sedimentation.

APA, Harvard, Vancouver, ISO, and other styles

7

Busse, Svenja, and Pauli Snoeijs. "Gradient responses of diatom communities in the Bothnian Bay, northern Baltic Sea." Nova Hedwigia 74, no. 3-4 (May 1, 2002): 501–25. http://dx.doi.org/10.1127/0029-5035/2002/0074-0501.

Full text

APA, Harvard, Vancouver, ISO, and other styles

8

Peltonen, Heikki, and Helge Balk. "The acoustic target strength of herring (Clupea harengus L.) in the northern Baltic Sea." ICES Journal of Marine Science 62, no. 4 (January 1, 2005): 803–8. http://dx.doi.org/10.1016/j.icesjms.2005.02.001.

Full text

Abstract:

Abstract The hydro-acoustic target strength (TS) of herring (Clupea harengus L.) was estimated from the catch composition of 19 pelagic-trawl hauls and from simultaneous recordings with a split-beam, 38 kHz echosounder. The data were collected in September 2000 during a Bothnian Sea survey in the northern Baltic Sea. The dependence of TS (in dB) on fish length (L, cm) was modelled with the equation TS = a log10 L + b. The fitted model was TS = 16.8 log10 L − 60.0. With a predefined slope of 20 the TS vs. log-fish length relationship was TS = 20 log10 L − 63.9. The analyses suggested that TS was higher in the Bothnian Sea than is assumed in most studies in the Baltic Sea. Applying the revised TS–length dependence considerably enhanced the agreement between the biomass estimates from hydroacoustics and those from a catche-at-age analysis (VPA).

APA, Harvard, Vancouver, ISO, and other styles

9

Hyttinen, O., A. T. Kotilainen, J. J. Virtasalo, P. Kekäläinen, I. Snowball, S. Obrochta, and T. Andrén. "Holocene stratigraphy of the Ångermanälven River estuary, Bothnian Sea." Geo-Marine Letters 37, no. 3 (December 5, 2016): 273–88. http://dx.doi.org/10.1007/s00367-016-0490-2.

Full text

APA, Harvard, Vancouver, ISO, and other styles

10

Yi, P., A. Aldahan, G. Possnert, X. L. Hou, P. He, and B. Wang. "Depth profiles of 129I species in the Bothnian Sea." Journal of Radioanalytical and Nuclear Chemistry 295, no. 2 (July 17, 2012): 1459–63. http://dx.doi.org/10.1007/s10967-012-1923-7.

Full text

APA, Harvard, Vancouver, ISO, and other styles

11

HYYTIÄINEN, K., H. AHTIAINEN, and J. HEIKKILÄ. "An integrated simulation model to evaluate national measures for the abatement of agricultural nutrients in the Baltic Sea." Agricultural and Food Science 18, no. 3-4 (January 3, 2009): 440–59. http://dx.doi.org/10.23986/afsci.5951.

Full text

Abstract:

This study introduces a prototype model for evaluating measures to abate agricultural nutrients in the Baltic Sea from a Finnish national perspective. The stochastic simulation model integrates nutrient dynamics of nitrogen and phosphorus in the sea basins adjoining the Finnish coast, nutrient loads from land and other sources, benefits from nutrient abatement (in the form of recreation and other ecosystem services) and the costs of agricultural abatement activities. The aim of the study is to present the overall structure of the model and to demonstrate its potential using preliminary parameters. The model is made flexible for further improvements in all of its ecological and economic components. The results of a sensitivity analysis suggest that investments in reducing the nutrient load from arable land in Finland would become profitable only if the neighboring countries in the northern Baltic committed themselves to similar reductions. Environmental investments for improving water quality yield the highest returns for the Bothnian Bay and the Gulf of Finland, with smaller returns for the Bothnian Sea. Somewhat surprisingly, in the Bothnian Bay the abatement activities become profitable from the national viewpoint, because the riverine loads from Finland represent a high proportion of the total nutrient loads. In the Gulf of Finland, this proportion is low, but the size of the coastal population benefiting from improved water quality is high.;

APA, Harvard, Vancouver, ISO, and other styles

12

Gårdmark, Anna, Örjan Östman, Anders Nielsen, Karl Lundström, Olle Karlsson, Jukka Pönni, and Teija Aho. "Does predation by grey seals (Halichoerus grypus) affect Bothnian Sea herring stock estimates?" ICES Journal of Marine Science 69, no. 8 (June 8, 2012): 1448–56. http://dx.doi.org/10.1093/icesjms/fss099.

Full text

Abstract:

Abstract Gårdmark, A., Östman, Ö., Nielsen, A., Lundström K., Karlsson O., Pönni, J., and Aho, T. 2012. Does predation by grey seals (Halichoerus grypus) affect Bothnian Sea herring stock estimates? – ICES Journal of Marine Science, 69: . Mortality of small pelagic fish due to marine mammals is generally considered to be low compared with other sources of mortality. With recent recoveries of marine mammal predators worldwide, this may no longer hold. The grey seal (Halichoerus grypus) population in the Bothnian Sea has increased fivefold since 1985. Its main prey, herring (Clupea harrengus), is a key species for fisheries in the region. Yet, current stock assessments assume constant natural mortality, leading to a risk of biased stock estimates with increasing predation and misleading analyses of herring population dynamics. We estimated grey seal predation from diet data and reanalysed herring spawning stock biomass (SSB) during 1973–2009. Accounting for predation increased the herring SSB 16% (maximum 19%), but this was within the confidence intervals when ignoring predation. Although mortality in older individuals was inflated when accounting for seal predation, this did not change the conclusions about drivers of herring dynamics. Accounting for grey seal predation is important for abundance estimates of old herring, but currently not for SSB estimates, given the great uncertainties in the standard assessment. The grey seal impact on Bothnian Sea herring will need to be reassessed if stock age composition, grey seal feeding preferences, or total stock development change.

APA, Harvard, Vancouver, ISO, and other styles

13

Deutsch, B., V. Alling, C. Humborg, F. Korth, and C. M. Mörth. "Tracing inputs of terrestrial high molecular weight dissolved organic matter within the Baltic Sea Ecosystem." Biogeosciences Discussions 9, no. 4 (April 16, 2012): 4483–512. http://dx.doi.org/10.5194/bgd-9-4483-2012.

Full text

Abstract:

Abstract. To test the hypothesis whether dissolved organic matter (DOM) in a high latitude marginal sea is dominated by terrestrial derived matter 10 stations were sampled along the salinity gradient of the central and northern Baltic Sea and were analyzed for concentrations of dissolved organic carbon as well as δ13C values of high molecular weight DOM. Different end-member-mixing models were applied to quantify the influence of terrestrial DOM and to test for conservative versus non-conservative behavior of the terrestrial dissolved organic matter in the different Baltic Sea basins. The share of terrestrial DOM to the total DOM was calculated for each station, ranging from 43 to 83%. This shows the high influence of terrestrial DOM inputs for the Baltic Sea ecosystem. The data also suggest that terrestrial DOM that reaches the open Baltic Sea is not subject to substantial removal anymore. However compared to riverine DOM concentrations our results indicate that substantial amounts of DOM (>50%) seems to be removed near the coastline during estuarine mixing. A budget approach yielded residence times for terrestrial DOM of 2.3, 2.7, and 4.1 yr for the Bothnian Bay, the Bothnian Sea and the Baltic Proper.

APA, Harvard, Vancouver, ISO, and other styles

14

Deutsch, B., V. Alling, C. Humborg, F. Korth, and C. M. Mörth. "Tracing inputs of terrestrial high molecular weight dissolved organic matter within the Baltic Sea ecosystem." Biogeosciences 9, no. 11 (November 13, 2012): 4465–75. http://dx.doi.org/10.5194/bg-9-4465-2012.

Full text

Abstract:

Abstract. To test the hypothesis whether high molecular weight dissolved organic matter (HMW-DOM) in a high latitude marginal sea is dominated by terrestrial derived matter, 10 stations were sampled along the salinity gradient of the central and northern Baltic Sea and were analyzed for concentrations of dissolved organic carbon as well as δ13C values of HMW-DOM. Different end-member-mixing models were applied to quantify the influence of terrestrial DOM and to test for conservative versus non-conservative behavior of the terrestrial DOM in the different Baltic Sea basins. The share of terrestrial DOM to the total HMW-DOM was calculated for each station, ranging from 43 to 83%. This shows the high influence of terrestrial DOM inputs for the Baltic Sea ecosystem. The data also suggest that terrestrial DOM reaching the open Baltic Sea is not subject to substantial removal anymore. However compared to riverine DOM concentrations, our results indicate that substantial amounts of HMW-DOM (> 50%) seem to be removed near the coastline during estuarine mixing. A budget approach yielded residence times for terrestrial DOM of 2.8, 3.0, and 4.5 yr for the Bothnian Bay, the Bothnian Sea and the Baltic Proper.

APA, Harvard, Vancouver, ISO, and other styles

15

Granskog, Mats A., Kristiina Virkkunen, David N. Thomas, Jens Ehn, Harri Kola, and Tõnu Martma. "Chemical properties of brackish water ice in the Bothnian Bay, the Baltic Sea." Journal of Glaciology 50, no. 169 (2004): 292–302. http://dx.doi.org/10.3189/172756504781830079.

Full text

Abstract:

AbstractThe behavior of majorions, δ18O, dissolved organic carbon (DOC) and trace elements was studied during the initial freezing of low-saline water (3 practical salinity units) in a freezing experiment. Samples were also collected from first-year sea ice from pack ice in the Bothnian Bay, northern Baltic Sea. During initial ice formation, the major-ion ratios in sea ice indicated variable behavior, with some ions showing relative enrichment (sulfate, calcium and magnesium), conservative behavior (sodium) or relative depletion (potassium) compared to sea water at the same salinity. DOC, iron and aluminum showed enrichment in the ice, while zinc was depleted to salinity. Lead was detected in surface snow-ice layers only, implying atmospheric accumulation. First-year sea ice, with a variable growth and thermal history, showed behavior for major ions similar to that observed in new ice. However, for trace elements the picture was much more complicated, most likely due to active secondary processes such as atmospheric supply and biological activity. Ice growth has a potential impact on the chemical budgets and cycling of some elements, especially those which are selectively rejected/retained during sea-ice formation, particularly in the shallow parts of the Bothnian Bay covered with a land-fast ice cover.

APA, Harvard, Vancouver, ISO, and other styles

16

NILSSON, JAN. "Allozyme variation of Macoma baltica (L.) in the Bothnian Sea." Hereditas 102, no. 2 (February 14, 2008): 277–80. http://dx.doi.org/10.1111/j.1601-5223.1985.tb00626.x.

Full text

APA, Harvard, Vancouver, ISO, and other styles

17

Soomere, T., and A. Räämet. "Long-term spatial variations in the Baltic Sea wave fields." Ocean Science Discussions 7, no. 6 (November 5, 2010): 1889–912. http://dx.doi.org/10.5194/osd-7-1889-2010.

Full text

Abstract:

Abstract. This study focuses on spatial patterns in linear trends of numerically reconstructed basic wave properties (average and extreme wave heights, wave period) in the Baltic Sea. Numerical simulations of wave conditions for 1970–2007, using the WAM wave model and adjusted geostrophic winds, revealed extensive spatial variations in long-term changes in both average and extreme wave heights in the Baltic Sea but almost no changes in the basinwide wave activity and wave periods. There has been a statistically significant decrease in the annual mean significant wave height by more than 10% between the islands of Öland and Gotland and in the southward sea area, and a substantial increase to the south-west of Bornholm, near the coast of Latvia, between Åland and the Swedish mainland, and between the Bothnian Sea and the Bothnian Bay. Variations in extreme wave heights (defined as the threshold for 1% of the highest waves each year) show similar patterns of changes. In several areas the trends in average and extreme wave heights are different. Such a complicated pattern of changes indicates that (i) different regions of the Baltic Sea basin have experienced widespread but essentially different changes in wind properties and (ii) many seemingly controversial trends and variations established in wave properties at different sites in the recent past may reflect the natural spatial variability in the Baltic Sea wave fields.

APA, Harvard, Vancouver, ISO, and other styles

18

Herman, A., J. Jedrasik, and M. Kowalewski. "Numerical modelling of thermodynamics and dynamics of sea ice in the Baltic Sea." Ocean Science 7, no. 2 (April 18, 2011): 257–76. http://dx.doi.org/10.5194/os-7-257-2011.

Full text

Abstract:

Abstract. In this paper, a numerical dynamic-thermo-dynamic sea-ice model for the Baltic Sea is used to analyze the variability of ice conditions in three winter seasons. The modelling results are validated with station (water temperature) and satellite data (ice concentration) as well as by qualitative comparisons with the Swedish Meteorological and Hydrological Institute ice charts. Analysis of the results addresses two major questions. One concerns effects of meteorological forcing on the spatio-temporal distribution of ice concentration in the Baltic. Patterns of correlations between air temperature, wind speed, and ice-covered area are demonstrated to be different in larger, more open sub-basins (e.g., the Bothnian Sea) than in the smaller ones (e.g., the Bothnian Bay). Whereas the correlations with the air temperature are positive in both cases, the influence of wind is pronounced only in large basins, leading to increase/decrease of areas with small/large ice concentrations, respectively. The other question concerns the role of ice dynamics in the evolution of the ice cover. By means of simulations with the dynamic model turned on and off, the ice dynamics is shown to play a crucial role in interactions between the ice and the upper layers of the water column, especially during periods with highly varying wind speeds and directions. In particular, due to the fragmentation of the ice cover and the modified surface fluxes, the ice dynamics influences the rate of change of the total ice volume, in some cases by as much as 1 km3 per day. As opposed to most other numerical studies on the sea-ice in the Baltic Sea, this work concentrates on the short-term variability of the ice cover and its response to the synoptic-scale forcing.

APA, Harvard, Vancouver, ISO, and other styles

19

Herman, A., J. Jedrasik, and M. Kowalewski. "Numerical modelling of thermodynamics and dynamics of sea ice in the Baltic Sea." Ocean Science Discussions 8, no. 1 (January 24, 2011): 113–57. http://dx.doi.org/10.5194/osd-8-113-2011.

Full text

Abstract:

Abstract. In this paper, a numerical dynamic-thermodynamic sea-ice model for the Baltic Sea is used to analyze the variability of ice conditions in three winter seasons. The modelling results are validated with station (water temperature) and satellite data (ice concentration) as well as by qualitative comparisons with the Swedish Meteorological and Hydrological Institute ice charts. Analysis of the results addresses two major questions. One concerns effects of meteorological forcing on the spatio-temporal distribution of ice concentration in the Baltic. Patterns of correlations between air temperature, wind speed, and ice-covered area are demonstrated to be different in larger, more open sub-basins (e.g., the Bothnian Sea) than in the smaller ones (e.g., the Bothnian Bay). Whereas the correlations with the air temperature are positive in both cases, the influence of wind is pronounced only in large basins, leading to increase/decrease of areas with small/large ice concentrations, respectively. The other question concerns the role of ice dynamics in the evolution of the ice cover. By means of simulations with the dynamic model turned on and off, the ice dynamics is shown to play a crucial role in interactions between the ice and the upper layers of the water column, especially during periods with highly varying wind speeds and directions. In particular, due to the fragmentation of the ice cover and the modified surface fluxes, the ice dynamics influences the rate of change of the total ice volume, in some cases by as much as 1 km3 per day. As opposed to most other numerical studies on the sea-ice in the Baltic Sea, this work concentrates on the short-term variability of the ice cover and its response to the synoptic-scale forcing.

APA, Harvard, Vancouver, ISO, and other styles

20

Ikävalko, Johanna. "Further observations on flagellates within sea ice in northern Bothnian Bay, the Baltic Sea." Polar Biology 19, no. 5 (April 16, 1998): 323–29. http://dx.doi.org/10.1007/s003000050253.

Full text

APA, Harvard, Vancouver, ISO, and other styles

21

Soomere, T., and A. Räämet. "Long-term spatial variations in the Baltic Sea wave fields." Ocean Science 7, no. 1 (February 18, 2011): 141–50. http://dx.doi.org/10.5194/os-7-141-2011.

Full text

Abstract:

Abstract. This study focuses on spatial patterns in linear trends of numerically reconstructed basic wave properties (average and extreme wave heights, wave periods) in the Baltic Sea under the assumption of no ice cover. Numerical simulations of wave conditions for 1970–2007, using the WAM wave model and adjusted geostrophic winds, revealed extensive spatial variations in long-term changes in both average and extreme wave heights in the Baltic Sea but almost no changes in the basinwide wave activity and wave periods. There has been a statistically significant decrease in the annual mean significant wave height by more than 10% between the islands of Öland and Gotland and in the southward sea area, and a substantial increase to the south-west of Bornholm, near the coast of Latvia, between the Åland Archipelago and the Swedish mainland, and between the Bothnian Sea and the Bothnian Bay. Variations in extreme wave heights (defined as the threshold for 1% of the highest waves each year) show similar patterns of changes. In several areas the trends in average and extreme wave heights are different. Such a complicated pattern of changes indicates that (i) different regions of the Baltic Sea basin have experienced widespread but essentially different changes in wind properties and (ii) many seemingly controversial trends and variations established in wave properties at different sites in the recent past may reflect the natural spatial variability in the Baltic Sea wave fields.

APA, Harvard, Vancouver, ISO, and other styles

22

Kallio, Niko, Matti Sahla, and Risto Kalliola. "Itämeren aleneva suolapitoisuus muokkaa Suomen rannikon lajien levinneisyyttä." Terra 132, no. 4 (December 16, 2020): 163–74. http://dx.doi.org/10.30677/terra.90638.

Full text

Abstract:

The physical and chemical properties of water are vital for aquatic organisms. Should changes in these conditions occur, responses would follow both in the distributions of species and ecosystem functioning. Water salinity is particularly critical because it induces osmotic stress and requires specific physiological adaptations from the living organisms. Current climate change models suggest increasing precipitation in the Baltic Sea catchment area and decreasing seawater salinity along the Finnish seacoast. In order to envisage potential consequences of decreasing salinity in the coastal ecosystems, we apply alternative Baltic Sea salinity scenarios based on climate change and species inventory data with GIS modelling to estimate possible changes in the distributions of four aquatic species within the next 50 years. The results suggest that marine species are to lose much of their current distribution areas: blue mussel may constrain its distribution into the Archipelago- and Bothnian Sea areas only, while eelgrass will likely disappear completely. In contrast, the studied freshwater species, brackish water sponge and the common water mosses, will strongly expand their distributions along the Finnish seacoast. Their currently isolated populations in the Gulf of Finland and the Gulf of Bothnia will expand their populations as far as the Archipelago Sea, which will thereby become a biogeographically interesting contact zone. As many of the studied organisms are keystone species, their changing distributions will induce cascade effects at the ecosystem level.

APA, Harvard, Vancouver, ISO, and other styles

23

Flinkman, Juha, Ilppo Vuorinen, and Eero Aro. "Planktivorous Baltic Herring (Clupea harengus) Prey Selectively on Reproducing Copepods and Cladocerans." Canadian Journal of Fisheries and Aquatic Sciences 49, no. 1 (January 1, 1992): 73–77. http://dx.doi.org/10.1139/f92-008.

Full text

Abstract:

Plankton and Baltic herring (Clupea harengus) were sampled simultaneously at nine sites in the northern Baltic Sea and Gulf of Bothnia. The stomachs from 45 herring and 54 plankton samples were analysed. The prey consisted mainly of adult mesozooplankters: copepods and cladocerans. Larger zooplankters (mysids and amphipods) were very rare in the stomachs as were the younger stages (copepodids) of copepods. The stomach contents of the fish changed from brackish water and neritic plankton species in the northern Baltic Proper to limnic species in the northern part of the Bothnian Sea. The diversity of plankton species decreased along with the salinity from south to north. Comparison of the plankton samples and herring stomach contents showed that prey with a large body size was selected as food. Generally this resulted in female copepods being chosen, since they are larger than males of the same species. Especially preferred food items were species and stages which carried conspicuous egg sacs (Eurytemora affinis females) or pigmented eggs and embryos (Bosmina longispina, Podon spp). Our results suggest that the Baltic herring is capable of exerting a regulative effect on the prey population comparable with that found in freshwater planktivores.

APA, Harvard, Vancouver, ISO, and other styles

24

Hietala, Riikka, Peter Lundberg, and Jenny A. U. Nilsson. "A note on the deep-water inflow to the Bothnian Sea." Journal of Marine Systems 68, no. 1-2 (November 2007): 255–64. http://dx.doi.org/10.1016/j.jmarsys.2006.12.004.

Full text

APA, Harvard, Vancouver, ISO, and other styles

25

Pekcan-Hekim, Zeynep, Anna Gårdmark, Agnes M. L. Karlson, Pirkko Kauppila, Mikaela Bergenius, and Lena Bergström. "The role of climate and fisheries on the temporal changes in the Bothnian Bay foodweb." ICES Journal of Marine Science 73, no. 7 (March 16, 2016): 1739–49. http://dx.doi.org/10.1093/icesjms/fsw032.

Full text

Abstract:

Abstract Climate change, eutrophication, and fishing are main pressures associated with changes in the abiotic and biotic environment in several sub-basins of the Baltic Sea. Identifying the nature of such changes is of relative importance for fisheries and environmental management. The Bothnian Bay is the northernmost sub-basin in the Baltic Sea and the responses of the foodweb to long-term changes in combined pressures have not been investigated. In this study, we explore long-term changes in the Bothnian Bay foodweb, represented by key species across all trophic levels over the past 34 years, and identify potential environmental and anthropogenic drivers. The results indicate that salinity is the most important driver to explain changes in the composition of the offshore biota in the Bothnian Bay. These changes are probably driven by indirect effects of salinity rather than bottom-up effects. A decline in the herring spawning-stock biomass was most plausibly attributed to an increased competition for food due to a parallel increase in vendace, which uses the same food resources (zooplankton and zoobenthos) and may benefit from declining salinity due to its limnic origin. A strong increase in the abundance of grey seal and ringed seal populations was seen in the late 2000s but was not related to any of the pressure variables analysed. Temperature and nutrients were not identified as important drivers of changes in the overall biota. Our study explores correlative relationships between variables and identifies potential interactions in the foodweb to generate hypotheses for further studies.

APA, Harvard, Vancouver, ISO, and other styles

26

Olsson, Jens, Eglė Jakubavičiūtė, Olavi Kaljuste, Niklas Larsson, Ulf Bergström, Michele Casini, Massimiliano Cardinale, Joakim Hjelm, and Pär Byström. "The first large-scale assessment of three-spined stickleback (Gasterosteus aculeatus) biomass and spatial distribution in the Baltic Sea." ICES Journal of Marine Science 76, no. 6 (April 26, 2019): 1653–65. http://dx.doi.org/10.1093/icesjms/fsz078.

Full text

Abstract:

Abstract Declines in predatory fish in combination with the impact of climate change and eutrophication have caused planktivores, including three-spined stickleback (Gasterosteus aculeatus), to increase dramatically in parts of the Baltic Sea. Resulting impacts of stickleback on coastal and offshore foodwebs have been observed, highlighting the need for increased knowledge on its population characteristics. In this article, we quantify abundance, biomass, size structure, and spatial distribution of stickleback using data from the Swedish and Finnish parts of the Baltic International Acoustic Survey (BIAS) during 2001–2014. Two alternative methods for biomass estimation suggest an increase in biomass of stickleback in the Baltic Proper, stable or increasing mean size over time, and larger individuals toward the north. The highest abundance was found in the central parts of the Baltic Proper and Bothnian Sea. The proportion of stickleback biomass in the total planktivore biomass increased from 4 to 10% in the Baltic Proper and averaged 6% of the total planktivore biomass in the Bothnian Sea. In some years, however, stickleback biomass has ranged from half to almost twice that of sprat (Sprattus sprattus) in both basins. Given the recent population expansion of stickleback and its potential role in the ecosystem, we recommend that stickleback should be considered in future monitoring programmes and in fisheries and environmental management of the Baltic Sea.

APA, Harvard, Vancouver, ISO, and other styles

27

Clason, Caroline C., Sarah L. Greenwood, Nick Selmes, James M. Lea, Stewart S. R. Jamieson, Faezeh M. Nick, and Per Holmlund. "Controls on the early Holocene collapse of the Bothnian Sea Ice Stream." Journal of Geophysical Research: Earth Surface 121, no. 12 (December 2016): 2494–513. http://dx.doi.org/10.1002/2016jf004050.

Full text

APA, Harvard, Vancouver, ISO, and other styles

28

Müller-Haeckel, Agnes. "Shade-adapted Algae beneath Ice and Snow in the Northern Bothnian Sea." Internationale Revue der gesamten Hydrobiologie und Hydrographie 70, no. 3 (1985): 325–34. http://dx.doi.org/10.1002/iroh.19850700303.

Full text

APA, Harvard, Vancouver, ISO, and other styles

29

Leonardsson, Kjell. "Growth and reproduction of Mesidotea entomon (Isopoda) in the northern Bothnian Sea." Ecography 9, no. 3 (October 1986): 240–44. http://dx.doi.org/10.1111/j.1600-0587.1986.tb01214.x.

Full text

APA, Harvard, Vancouver, ISO, and other styles

30

Salminen, M., E. Erkamo, and J. Salmi. "Diet of post-smolt and one-sea-winter Atlantic salmon in the Bothnian Sea, Northern Baltic." Journal of Fish Biology 58, no. 1 (January 2001): 16–35. http://dx.doi.org/10.1111/j.1095-8649.2001.tb00496.x.

Full text

APA, Harvard, Vancouver, ISO, and other styles

31

Olofsson, Malin, Isabell Klawonn, and Bengt Karlson. "Nitrogen fixation estimates for the Baltic Sea indicate high rates for the previously overlooked Bothnian Sea." Ambio 50, no. 1 (April 20, 2020): 203–14. http://dx.doi.org/10.1007/s13280-020-01331-x.

Full text

Abstract:

AbstractDense blooms of diazotrophic filamentous cyanobacteria are formed every summer in the Baltic Sea. We estimated their contribution to nitrogen fixation by combining two decades of cyanobacterial biovolume monitoring data with recently measured genera-specific nitrogen fixation rates. In the Bothnian Sea, estimated nitrogen fixation rates were 80 kt N year−1, which has doubled during recent decades and now exceeds external loading from rivers and atmospheric deposition of 69 kt year−1. The estimated contribution to the Baltic Proper was 399 kt N year−1, which agrees well with previous estimates using other approaches and is greater than the external input of 374 kt N year−1. Our approach can potentially be applied to continuously estimate nitrogen loads via nitrogen fixation. Those estimates are crucial for ecosystem adaptive management since internal nitrogen loading may counteract the positive effects of decreased external nutrient loading.

APA, Harvard, Vancouver, ISO, and other styles

32

VALTONEN, E. T., K. PULKKINEN, R. POULIN, and M. JULKUNEN. "The structure of parasite component communities in brackish water fishes of the northeastern Baltic Sea." Parasitology 122, no. 4 (April 2001): 471–81. http://dx.doi.org/10.1017/s0031182001007491.

Full text

Abstract:

We used nestedness analysis to seek non-random patterns in the structure of component communities of metazoan parasites collected from 31 sympatric fish species from the northeastern Bothnian Bay, the most oligohaline area of the Baltic Sea. Only 8 marine parasite species were found among the 63 species recorded, although some marine fish species reproduce in the bay and others occasionally visit the area. Marine parasite species can utilize both freshwater and marine fish species as intermediate or final hosts, and marine fish can harbour freshwater parasite species. This exchange of parasite species between marine and freshwater fish has probably resulted from ecological factors acting over short time scales rather than from evolutionary processes acting over longer time; the key factor probably being the immediate presence of suitable intermediate and definitive hosts. Marine fish were expected to harbour species-poor parasite communities consisting mainly of generalists acquired from the sympatric freshwater fish species, which would result in a nested pattern among the different component communities. However, an anti-nested pattern was found in the component communities of metazoan parasites of fishes from the Bothnian Bay. A likely explanation for the observed pattern is that there are specialist parasite species, the majority of which are cestodes, in some of the freshwater fish species which otherwise have depauperate parasite communities.

APA, Harvard, Vancouver, ISO, and other styles

33

Saikku, Reetta, Minna Alhosalo, Sari Repka, and Anne Erkkilä. "Reviewing the History of Natural Sciences Research on the Bothnian Sea, 1975–2008." AMBIO 39, no. 7 (June 16, 2010): 524–27. http://dx.doi.org/10.1007/s13280-010-0056-x.

Full text

APA, Harvard, Vancouver, ISO, and other styles

34

Löptien, U., and L. Axell. "Ice and AIS: ship speed data and sea ice forecasts in the Baltic Sea." Cryosphere 8, no. 6 (December 23, 2014): 2409–18. http://dx.doi.org/10.5194/tc-8-2409-2014.

Full text

Abstract:

Abstract. The Baltic Sea is a seasonally ice-covered marginal sea located in a densely populated area in northern Europe. Severe sea ice conditions have the potential to hinder the intense ship traffic considerably. Thus, sea ice fore- and nowcasts are regularly provided by the national weather services. Typically, the forecast comprises several ice properties that are distributed as prognostic variables, but their actual usefulness is difficult to measure, and the ship captains must determine their relative importance and relevance for optimal ship speed and safety ad hoc. The present study provides a more objective approach by comparing the ship speeds, obtained by the automatic identification system (AIS), with the respective forecasted ice conditions. We find that, despite an unavoidable random component, this information is useful to constrain and rate fore- and nowcasts. More precisely, 62–67% of ship speed variations can be explained by the forecasted ice properties when fitting a mixed-effect model. This statistical fit is based on a test region in the Bothnian Sea during the severe winter 2011 and employs 15 to 25 min averages of ship speed.

APA, Harvard, Vancouver, ISO, and other styles

35

Löptien, U., and L. Axell. "Ice and AIS: ship speed data and sea ice forecasts in the Baltic Sea." Cryosphere Discussions 8, no. 4 (July 15, 2014): 3811–28. http://dx.doi.org/10.5194/tcd-8-3811-2014.

Full text

Abstract:

Abstract. The Baltic Sea is a seasonally ice covered marginal sea located in a densely populated area in northern Europe. Severe sea ice conditions have the potential to hinder the intense ship traffic considerably. Thus, sea ice fore- and nowcasts are regularly provided by the national weather services. Typically, several ice properties are allocated, but their actual usefulness is difficult to measure and the ship captains must determine their relative importance and relevance for optimal ship speed and safety ad hoc. The present study provides a more objective approach by comparing the ship speeds, obtained by the Automatic Identification System (AIS), with the respective forecasted ice conditions. We find that, despite an unavoidable random component, this information is useful to constrain and rate fore- and nowcasts. More precisely, 62–67% of ship speed variations can be explained by the forecasted ice properties when fitting a mixed effect model. This statistical fit is based on a test region in the Bothnian Bay during the severe winter 2011 and employes 15 to 25 min averages of ship speed.

APA, Harvard, Vancouver, ISO, and other styles

36

Pöykiö, R., H. Nurmesniemi, V. A. Kivilinna, and T. Kuokkanen. "Long-term changes in the effluent loads from pulp and paper mills, the introduction of BAT technology, and their effects on extractable organic halogens concentrations in sediment in part of the Bothnian Bay." Water Science and Technology 62, no. 6 (September 1, 2010): 1288–95. http://dx.doi.org/10.2166/wst.2010.421.

Full text

Abstract:

The Bothnian Bay at Kemi, which is the northernmost basin of the Gulf of Bothnia in the Baltic Sea, is affected by effluents from point sources such as pulp and paper mills and municipal sewage plant. During the period 1988–2008, the accumulated values of effluent volume, BOD7, CODCr, Tot-P, Tot-N, TSS and AOX from these point sources fell considerably as follows: 1) effluent volume by 24%, BOD7 by 92%, CODCr by 74%, Tot-P by 79%, Tot-N by 38%, TSS by 76% and AOX by 93%. The decrease in the effluent loadings is due to the introduction of Best Available Techniques (BAT) for the production processes and wastewater treatment at the pulp and paper mills. According to the long-term monitoring program that has been carried out every third year between 1997–2009, the decreasing trend in EOX—concentrations in the top 2 cm of the bottom sediment reflects the decrease in organochlorine discharges (AOX) from the mills. In 1997, the EOX concentrations in bottom sediment varied between 3–70 μg of Cl g−1 (dry weight), and in 2009 between 1.2–31 μg of Cl g−1 (dry weight).

APA, Harvard, Vancouver, ISO, and other styles

37

Granskog, Mats A., Jari Uusikivi, Alberto Blanco Sequeiros, and Eloni Sonninen. "Relation of ice growth rate to salt segregation during freezing of low-salinity sea water (Bothnian Bay, Baltic Sea)." Annals of Glaciology 44 (2006): 134–38. http://dx.doi.org/10.3189/172756406781811259.

Full text

Abstract:

AbstractSalt segregation and isotopic fractionation during sea-ice formation can be parameterized as a function of the ice growth rate. We performed a study to investigate if the salt segregation models derived for saline sea-ice studies are pertinent during the growth of Baltic Sea ice in brackish water. We used a time series of ice-salinity profiles and modeled growth rates to examine the relationship between effective salt segregation and growth rate. The results show that models derived for saline sea water are not directly applicable for use in the brackish waters of the Baltic Sea. We derived a simple model for the effective salt segregation in relation to ice growth rate, for a wide range of growth rates, pertinent for use in low-salinity Baltic Sea conditions and in the future development of a Baltic Sea ice salinity model.

APA, Harvard, Vancouver, ISO, and other styles

38

Keinänen, Marja, Annika Uddström, Jaakko Mikkonen, Michele Casini, Jukka Pönni, Timo Myllylä, Eero Aro, and Pekka J. Vuorinen. "The thiamine deficiency syndrome M74, a reproductive disorder of Atlantic salmon (Salmo salar) feeding in the Baltic Sea, is related to the fat and thiamine content of prey fish." ICES Journal of Marine Science 69, no. 4 (March 19, 2012): 516–28. http://dx.doi.org/10.1093/icesjms/fss041.

Full text

Abstract:

Abstract Keinänen, M., Uddström, A., Mikkonen, J., Casini, M., Pönni, J., Myllylä, T., Aro, E., and Vuorinen, P. J. 2012. The thiamine deficiency syndrome M74, a reproductive disorder of Atlantic salmon (Salmo salar) feeding in the Baltic Sea, is related to the fat and thiamine content of prey fish. – ICES Journal of Marine Science, 69: 516–528. This study clarifies how the diet of Baltic salmon leads to thiamine deficiency in eggs, and consequently to M74 mortality of yolk-sac fry. The main prey species, sprat (Sprattus sprattus) and herring (Clupea harengus membras), and their biomass in the Baltic Proper (BPr) and the Bothnian Sea, the two feeding grounds of salmon originating from the northern Gulf of Bothnia rivers, are compared. The thiamine concentration of both prey species is lowest in the youngest age groups. Because average fat content and energy density are greater in sprat than in herring, and greatest in youngest sprat, the supply of thiamine per unit energy is least in a diet containing many young sprat. Also, the greater is the supply of thiamine and fat from sprat in the southern BPr in the preceding year, the lower the concentration of thiamine in salmon eggs. Thiamine deficiency in eggs results from an unbalanced diet abundant in fatty prey fish, such as young sprat, from which the supply of thiamine is insufficient in proportion to the supply of energy and unsaturated fatty acids for salmon, which must undergo a long prespawning fasting period.

APA, Harvard, Vancouver, ISO, and other styles

39

Valtonen, E. Tellervo, Hans-Peter Fagerholm, and Eero Helle. "Contracaecum osculatum (Nematoda: Anisakidae) in fish and seals in Bothnian Bay (northeastern Baltic Sea)." International Journal for Parasitology 18, no. 3 (April 1988): 365–70. http://dx.doi.org/10.1016/0020-7519(88)90146-4.

Full text

APA, Harvard, Vancouver, ISO, and other styles

40

Dijkstra, Nikki, Nadine B. Quintana Krupinski, Masako Yamane, Stephen P. Obrochta, Yosuke Miyairi, Yusuke Yokoyama, and Caroline P. Slomp. "Holocene Refreshening and Reoxygenation of a Bothnian Sea Estuary Led to Enhanced Phosphorus Burial." Estuaries and Coasts 41, no. 1 (June 21, 2017): 139–57. http://dx.doi.org/10.1007/s12237-017-0262-x.

Full text

APA, Harvard, Vancouver, ISO, and other styles

41

Busse, Svenja, and Pauli Snoeijs. "Gradient responses of diatom communities in the Bothnian Sea (northern Baltic Sea), with emphasis on responses to water movement." Phycologia 42, no. 5 (September 2003): 451–64. http://dx.doi.org/10.2216/i0031-8884-42-5-451.1.

Full text

APA, Harvard, Vancouver, ISO, and other styles

42

Brinza, Loredana, Charlotta A. Nygård, Matthew J. Dring, Maria Gavrilescu, and Liane G. Benning. "Cadmium tolerance and adsorption by the marine brown alga Fucus vesiculosus from the Irish Sea and the Bothnian Sea." Bioresource Technology 100, no. 5 (March 2009): 1727–33. http://dx.doi.org/10.1016/j.biortech.2008.09.041.

Full text

APA, Harvard, Vancouver, ISO, and other styles

43

Torniainen, Jyrki, Pekka J. Vuorinen, Roger I. Jones, Marja Keinänen, Stefan Palm, Kristiina A. M. Vuori, and Mikko Kiljunen. "Migratory connectivity of two Baltic Sea salmon populations: retrospective analysis using stable isotopes of scales." ICES Journal of Marine Science 71, no. 2 (September 16, 2013): 336–44. http://dx.doi.org/10.1093/icesjms/fst153.

Full text

Abstract:

Abstract Torniainen, J., Vuorinen, P. J., Jones, R. I., Keinänen, M., Palm, S., Vuori, K. A. M., and Kiljunen, M. 2014. Migratory connectivity of two Baltic Sea salmon populations: retrospective analysis using stable isotopes of scales. – ICES Journal of Marine Science, 71: 336–344. Migratory connectivity refers to the extent to which individuals of a migratory population behave in unison, and has significant consequences for the ecology, evolution and conservation of migratory animals. We made a retrospective assessment of the migratory connectivity of River Simojoki and River Kymijoki populations of Atlantic salmon Salmo salar L. by using stable isotope analysis of archived scales to identify the final feeding areas used before ascending rivers for spawning. We also tested differences in migratory connectivity between wild and hatchery-reared salmon and compared Carlin-tag recoveries with salmon scale stable isotope analysis as methods for studying salmon migrations. Stable isotope (δ13C, δ15N) values from the last growth region of scales from salmon caught ascending their natal rivers were compared via discriminant analysis with those from scales of salmon caught in different Baltic Sea areas during 1989–2011. Most River Simojoki salmon had likely fed in the Baltic Proper (mean ± SD for ascending fish probability 0.59 ± 0.32) with secondary likely feeding areas in the Bothnian Sea (0.21 ± 0.26) and the Gulf of Finland (0.20 ± 0.27). Most River Kymijoki salmon had likely fed in the Gulf of Finland (0.71 ± 0.42) with the Baltic Proper (0.29 ± 0.41) a secondary feeding area. The results did not indicate the Bothnian Sea to be an important feeding area. The two salmon populations showed weak migratory connectivity and rather fixed areal preference throughout the record irrespective of wild or stocked origin. Although the results from the scale stable isotope analyses were broadly consistent with previously reported Carlin-tag recoveries, we argue that the stable isotope approach offers several important advantages in the study of salmon migratory behaviour.

APA, Harvard, Vancouver, ISO, and other styles

44

Håkanson, L., P. Jonsson, B. Jonsson, and K. Martinsen. "Distribution of Chlorinated Organic Substances from Pulp Mills." Water Science and Technology 20, no. 2 (February 1, 1988): 25–36. http://dx.doi.org/10.2166/wst.1988.0043.

Full text

Abstract:

This is a report from a project sponsored by the National Swedish Environmental Protection Board, “Environment/Cellulose”, which focuses on the chemical character, distribution pattern and potential ecological hazards of chlorinated organic substances from pulp mills. This paper deals primarily with the spread of EOCl in the sediments of the Bothnian Sea and the northern part of the Baltic. Results:–there exists a clear linkage between the spread and the concentration of EOC1 in surficial sediments and the bottom dynamic conditions, such that high contents (highest 903 µg/g ds) generally appear close to the pulp mills and within areas of accumulation, and low contents (< 1 µg/g ds) appear in sediments from areas of erosion and transportation;–diffuse leakage from land, emissions from urban areas, or from steel and petrochemical industries do not seem to be of any major importance for this characteristic distribution pattern of EOC1 in sediments;–sediment core data indicate an ongoing increase in EOCl-contamination;–the concentrations of EOC1 in sediments from lakes and coastal areas far from any known pulp mills are low;–the main conclusion from these studies is that EOC1 is distributed over vast areas and that it is hard or impossible to find any areas in the Bothnian Sea unaffected by these substances. It should be noted that in all assessments of ecological risks, it is important to have knowledge of the size and character of the impact areas, but that it may be difficult to select biological test organisms and actually establish ecological effects.

APA, Harvard, Vancouver, ISO, and other styles

45

Åberg, F., and F. E. Wickman. "Variations of 87Sr/86Sr in Water from Streams Discharging into the Bothnian Bay, Baltic Sea." Hydrology Research 18, no. 1 (February 1, 1987): 33–42. http://dx.doi.org/10.2166/nh.1987.0003.

Full text

Abstract:

The 87Sr/86Sr ratio in 53 water samples were analysed, 26 from streams in Sweden, 22 from streams in Finland and 5 from the Bothnian Bay itself. The brackish seawater of the bay had the isotope ratio 0.7095, while the stream-water samples varied from 0.7177 to 0.7366. The weighted average isotope ratio with respect to discharges was 0.7313, this high ratio reflecting the dominance of granitic Proterozoic rocks in the region. For streams with an average discharge between 1-40 m3/s the isotope ratio was within the interval 0.718-0.736, while those with discharges >150 m3/s defined an interval of 0.728-0.735. The variations in isotope ratios are discussed with respect to bedrock geology of drainage basins, possible effects of seawater inundations and Postglacial uplift combined with the complex history of the Baltic Sea.

APA, Harvard, Vancouver, ISO, and other styles

46

Eriksson, Britas Klemens, Gustav Johansson, and Pauli Snoeijs. "Long-term changes in the sublittoral zonation of brown algae in the southern Bothnian Sea." European Journal of Phycology 33, no. 3 (August 1998): 241–49. http://dx.doi.org/10.1080/09670269810001736743.

Full text

APA, Harvard, Vancouver, ISO, and other styles

47

Rasigraf, Olivia, Julia Schmitt, Mike S. M. Jetten, and Claudia Lüke. "Metagenomic potential for and diversity of N-cycle driving microorganisms in the Bothnian Sea sediment." MicrobiologyOpen 6, no. 4 (May 23, 2017): e00475. http://dx.doi.org/10.1002/mbo3.475.

Full text

APA, Harvard, Vancouver, ISO, and other styles

48

Ahlgren, Joakim, Anders Grimvall, Anders Omstedt, Carl Rolff, and Johan Wikner. "Temperature, DOC level and basin interactions explain the declining oxygen concentrations in the Bothnian Sea." Journal of Marine Systems 170 (June 2017): 22–30. http://dx.doi.org/10.1016/j.jmarsys.2016.12.010.

Full text

APA, Harvard, Vancouver, ISO, and other styles

49

Piiparinen, Jonna, Harri Kuosa, and Janne-Markus Rintala. "Winter-time ecology in the Bothnian Bay, Baltic Sea: nutrients and algae in fast ice." Polar Biology 33, no. 11 (October 5, 2010): 1445–61. http://dx.doi.org/10.1007/s00300-010-0771-6.

Full text

APA, Harvard, Vancouver, ISO, and other styles

50

Vahteri, Petri, Kevin O'Brien, and Ilppo Vuorinen. "Zonation and spatial distribution of littoral fish communities from the southwestern Finnish coast (Archipelago and Bothnian Sea, Northern Baltic Sea)." Estuarine, Coastal and Shelf Science 82, no. 1 (March 2009): 35–40. http://dx.doi.org/10.1016/j.ecss.2008.11.016.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Journal articles on the topic 'Bothnian Sea'

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles