14 resultados para NTM-centralen i Egentliga Finland

em Publishing Network for Geoscientific


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According to Solitander C. P., the extraction of lake ore from Eastern Finland lakes considerably rose in the 1870 - 1880 period in relation with the increasing demand from the ironworks being operated in the region. In St. Petersburg, Nicholas Putiloff, a business tycoon and State Minister owned the Haapakosken, Huutokosken and Oravin ironworks which were using 99% of lake ore for their supply. During this period the biggest production came from lake Sysmäjärvi in the Joroinen county with 3676 tonnes at an average concentration of 35.94% Fe, 4.55% Mn, 0.26% P and 0.04% S. The Värtsiironworks used the lake ore coming from 49 lakes, the biggest production coming from lake Loitimojärvi with 14535 tonnes of ore with a medium at concentration of 30.8% Fe. Möhkö ironworks took advantage of the 59 lakes, the largest of which was from lake Koitere with 4301 tonnes at 41.3% Fe. The Karttula ironworks were also significant in the consumption of ferromanganese lake ore.

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Distributions of major and trace elements in ferromanganese nodules, which are buried or exposed on the sea floor and in host sediments, were studied in ten concretion/sediment pairs by various physical and chemical methods. It was established that, in addition to Fe and Mn, a limited number of major and trace elements (P, Ca, Sr, Ba, Mo, Co, Zn, Ni, As, Pb, Sb, Tl, U, W, Y, and Ga) is accumulated with variable degree of intensity (relative to sediments) in the nodules. The maximal content of Mn in the nodules is 100 times higher than in the host sediments, whereas for all other elements listed above these ratios vary from more than one to 10-20. Manganese and, to a lesser extent, Ba and Sr are concentrated in the buried concretions. Other elements are primarily concentrated in concretions exposed on the sea floor. The occurrence mode of the concretions and compositional data on interstitial water suggest that metals in the concretions derive from seawater and suspended particulates, in addition to sediments. Burial of concretions in the sediment pile is accompanied by alteration of their composition, accumulation of Mn (relative to Fe), and loss of several associated metals.

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The Baltic Sea is a unique environment as the largest body of brackish water in the world. Acidification of the surface oceans due to absorption of anthropogenic CO2 emissions is an additional stressor facing the pelagic community of the already challenging Baltic Sea. To investigate its impact on trace gas biogeochemistry, a large-scale mesocosm experiment was performed off Tvärminne Research Station, Finland in summer 2012. During the second half of the experiment, dimethylsulphide (DMS) concentrations in the highest fCO2 mesocosms (1075-1333 µatm) were 34 % lower than at ambient CO2 (350 µatm). However the net production (as measured by concentration change) of seven halocarbons analysed was not significantly affected by even the highest CO2 levels after 5 weeks exposure. Methyl iodide (CH3I) and diiodomethane (CH2I2) showed 15 % and 57 % increases in mean mesocosm concentration (3.8 ± 0.6 pmol L-1 increasing to 4.3 ± 0.4 pmol L-1 and 87.4 ± 14.9 pmol L-1 increasing to 134.4 ± 24.1 pmol L-1 respectively) during Phase II of the experiment, which were unrelated to CO2 and corresponded to 30 % lower Chl-? concentrations compared to Phase I. No other iodocarbons increased or showed a peak, with mean chloroiodomethane (CH2ClI) concentrations measured at 5.3 (± 0.9) pmol L-1 and iodoethane (C2H5I) at 0.5 (± 0.1) pmol L-1. Of the concentrations of bromoform (CHBr3; mean 88.1 ± 13.2 pmol L-1), dibromomethane (CH2Br2; mean 5.3 ± 0.8 pmol L-1) and dibromochloromethane (CHBr2Cl, mean 3.0 ± 0.5 pmol L-1), only CH2Br2 showed a decrease of 17 % between Phases I and II, with CHBr3 and CHBr2Cl showing similar mean concentrations in both Phases. Outside the mesocosms, an upwelling event was responsible for bringing colder, high CO2, low pH water to the surface starting on day t16 of the experiment; this variable CO2 system with frequent upwelling events implies the community of the Baltic Sea is acclimated to regular significant declines in pH caused by up to 800 µatm fCO2. After this upwelling, DMS concentrations declined, but halocarbon concentrations remained similar or increased compared to measurements prior to the change in conditions. Based on our findings, with future acidification of Baltic Sea waters, biogenic halocarbon emissions are likely to remain at similar values to today, however emissions of biogenic sulphur could significantly decrease from this region.

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This paper discusses the occurrence of manganese-rich concretions in the lakes of Northern Savolax in Eastern Finland. The samples were collected in the summer of 1905 and left to dry for 2 months at room temperature. The quantity of H2O mentionned in the analysis was obtained by dessication at 155°C. The amount of Mn is calulated as MnO2 although other valences might be present in the samples. The contents in CO2 and organic substances was not determined. J. Aschan determined that as a general rule, in Finland the manganese rich lake deposits are rather associated with soft bottom sediments while the iron rich deposits are more assocaited with hard or sandy bottoms.