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Rynek tantalu na początku XXI wieku

Krzak Mariusz, Gałaś Andrzej, Król Katarzyna

Przegląd Geologiczny

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2021

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Vol. 69, nr 4

234--243

EN

Tantalum, despite the low consumption level, is one of the strategically important metals for the world economy. In terms of the world production volume, it places oneself on a distant position; however, its price was one of the highest at the beginning of the 21st century. Tantalum is a transition metal with a high melting point and high chemical resistance, which determines the spectrum of its applications. It is used mainly in the capacitors production, sputtering and as an additive for superalloys. The 21stcentury is a period of noticeable changes in the structure of quantitative supplies, consumption centres and price fluctuation. There are numerous but small centres of primary production (artisanal mines) in Africa. Sources of tantalum raw-materials (mineral deposits and its reserves), basic factors determining the economic situation on the market, substitution possibilities and the prices evolution are presented and assessed in the paper. Marginal significance of the economy of tantalum raw materials for Poland is mentioned.

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Composition and diel vertical distribution of euphausiid larvae (calyptopis stage) in the deep southern Adriatic

Gangai Zovko B., Lučić D., Hure M., Onofri I., Pestorić B.

Oceanologia

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2018

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No. 60 (2)

128--138

EN

Diel changes in the vertical distribution and abundance of calyptopes were studied in the deepest area of the southern Adriatic over four seasons (July 2003, February 2004, October 2004, April 2009). Temperature variations were limited to the upper 100 m and salinity variations were small. Of previously known adult euphausiid species – 12 for the Adriatic (Gangai et al., 2012) and 13 for the Mediterranean (Mavidis et al., 2005) – calyptopes of 11 species of euphausiids were recorded. Abundance of calyptopes of all species was the highest in spring. Species were characterized according to their mean depth: surface (0-50 m), sub-surface (50-200 m), mesopelagic (200-800 m), or bathypelagic (800-1200 m) and vertical dispersion (scattered or non-scattered). Four diel patterns emerged: (i) nocturnal ascent to upper layers (Euphausia brevis, E. hemigibba, E. krohnii, Nematoscelis megalops, N. couchii), (ii) migration to upper layers at middle of the day and at night, and descent during the morning and evening (Stylocheiron maximum – only winter), (iii) weakly-migrating or non-migrating (S. longicorne), (iv) irregular migration independent of the day/night cycle (S. abbreviatum, S. maximum – during spring, summer and autumn, T. aequalis).

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Seasonal variability in the population dynamics of the main mesozooplankton species in the Gulf of Gdańsk (southern Baltic Sea): production and mortality rates

Dzierzbicka-Głowacka L., Kalarus M., Musialik-Koszarowska M., Lemieszek A., Żmijewska M. I.

Oceanologia

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2015

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No. 57 (1)

78--85

EN

This manuscript is a continuation of the results presented in the earlier work by Dzierzbicka-Głowacka et al. (2013). Major purpose of this study is to characterize population dynamics of three major Baltic calanoid copepod species (Acartia spp., Temora longicornis and Pseudocalanus sp.) in the Gulf of Gdańsk during the years 2006–2007. This paper focuses mostly on biomass estimation, production and mortality rates. All three species had the highest observed biomass in summer 2007 and it was 12.62, 9.16 and 0.80 mg C m-3for Acartia spp., T. longicornis and Pseudocalanus sp., respectively, while highest daily production rates for those species were 28.22, 18.47, 1.34 mg C m-2, all recorded in summer 2007. Mortality rates were calculated for all copepodite stages of selected species, and in most cases highest values were observed during summer seasons

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Abundance and production of bacteria in a marine beach (Southern Baltic Sea)

Podgórska B., Mudryk Z., Skórczewski P.

Polish Journal of Ecology

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2008

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Vol. 56, nr 3

405-414

EN

The paper presents the results of the study of abundance, biomass, mean cell volume and secondary production of bacteria inhabiting a marine-bay sandy beach, at southern Baltic Sea coast (Sopot) in summer season. The differences of bacteriological parameters among sites across beach horizontal profile were determined. Maximal value of the total bacteria numbers (8.59 [plus or minus] 0.73 x 10[^7]cells g[^-1] dw), biomass (15.2 [plus or minus] 4.4 [my]g C g[^-1] dw) and cell volume of bacterium (0.056 [plus or minus] 0.011 [my]m3) was noted at the waterline and bacterial secondary production was highest in the dune (172.3 [plus or minus] 86.6 [my]g C g[^-1] dw d[^-1]) and at the waterline (119.9 [plus or minus] 40.5 [my]g C g[^-1] dw d[^-1]). Marked differences in the level of bacteriological parameters between surface and subsurface sand layers were estimated. In the sea, at the waterline and in the middle of the beach higher numbers of bacteria, their biomass and secondary production were found in the surface (0.1 cm) than in the subsurface (5.10 cm) sand layers. A reverse situation was observed in the dune.