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Wyszukujesz frazę "water cycle" wg kryterium: Temat


Wyświetlanie 1-5 z 5
Tytuł:
Dissolved oxygen variability in the Southern Baltic Sea in 2013—2018
Autorzy:
Rak, D.
Walczowski, W.
Dzierzbicka-Glowacka, L.
Shchuka, S.
Powiązania:
https://bibliotekanauki.pl/articles/2079094.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
dissolved oxygen concentration
oxygenation
sea water
water column
surface layer
seasonal cycle
major inflow
Baltic Sea
Opis:
This paper discusses changes in the dissolved oxygen concentration (DOC) in the southern Baltic Sea. The oxygenation of the whole water column was estimated. Monthly mean DOCs, as well as a detailed description of the annual surface layer dissolved oxygen (DO) cycle, are presented. The DO cycle at the surface is characterized by two maxima in March/April and November, and by two minima in July/August and December. The DO decline time after the major Baltic inflow (MBI) in 2014 was estimated at about 10 months for the Bornholm Deep and Słupsk Furrow. Whereas the Bornholm Basin was relatively well oxygenated, low oxygen concentrations (<4 mg l−1) were measured in the deep layer of the Gdańsk Deep throughout the inflow period. In addition, the cod spermatozoa activation layer together with the neutral egg buoyancy layer for the Bornholm Basin and Słupsk Furrow are discussed on the basis of the measured DOCs and the variability in hydrographic conditions.
Źródło:
Oceanologia; 2020, 62, 4PA; 525-537
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Annual reproductive cycle in two free living populations of three-spined stickleback (Gasterosteus aculeatus L.): patterns of ovarian and testicular development
Autorzy:
Sokolowska, E.
Kulczykowska, E.
Powiązania:
https://bibliotekanauki.pl/articles/47889.pdf
Data publikacji:
2006
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
free living population
stickleback
gonad
environment change
reproductive cycle
wild population
Oliva Stream
natural habitat
fresh water
breeding
Vistula River
Gasterosteus aculeatus
spermatogenesis
vitellogenesis
Opis:
The annual reproductive cycle in two wild populations of three-spined stickleback was studied. Sticklebacks from the Dead Vistula River (Martwa Wisła) (brackish water) and the Oliva Stream (Potok Oliwski) (freshwater) were exposed to annual environmental changes in their natural habitats. Ovaries and livers (females), and testes and kidneys (males) were collected during 1–2 years. The gonadosomatic IG, hepatosomatic IH, nephrosomatic IN indices, kidney epithelium height (KEH) and size of oocytes were calculated. The number of mature oocytes and percentage of ovulating females were determined during the spawning season. Histological changes in the ovaries and testes were described throughout a year. Annual reproductive cycles were similar in both populations of sticklebacks. This is the first histological and morphological study carried out throughout a year, simultaneously in two wild populations of three-spined sticklebacks inhabiting different environments. An improved scale of gonadal development in conjunction with the determined indices and fecundity give a comprehensive description of the reproductive cycle. These newobserv ations, in combination with previously reported features, provide a universal scale that can be successfully used to distinguish all phases of gametogenesis in sticklebacks in different habitats.
Źródło:
Oceanologia; 2006, 48, 1
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Particulate organic carbon in the Southern Baltic Sea: numerical simulations and experimental data
Autorzy:
Dzierzbicka-Glowacka, L.
Kulinski, K.
Maciejewska, A.
Jakacki, J.
Pempkowiak, J.
Powiązania:
https://bibliotekanauki.pl/articles/48082.pdf
Data publikacji:
2010
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
Baltic Sea
Gdansk Deep
calcification
carbon cycle
detritus
nutrient
organic compound
organic matter
particulate organic carbon
photosynthesis
phytoplankton
primary production
sea water
validation
zooplankton
Opis:
Particulate Organic Carbon (POC) is an important component in the carbon cycle of land-locked seas. In this paper, we assess the POC concentration in the Gdańsk Deep, southern Baltic Sea. Our study is based on both a 1D POC Model and current POC concentration measurements. The aim is twofold: (i) validation of simulated concentrations with actual measurements, and (ii) a qualitative assessment of the sources contributing to the POC pool. The POC model consists of six coupled equations: five diffusion-type equations for phytoplankton, zooplankton, pelagic detritus and nutrients (phosphate and total inorganic nitrogen) and one ordinary differential equation for detritus at the bottom. The POC concentration is determined as the sum of phytoplankton, zoo-plankton and pelagic detritus concentrations, all expressed in carbon equivalents. Bacteria are not simulated in this paper. The observed large fluctuations of POC concentrations are attributed to its appreciable seasonal variability. The maximum concentration of POC varied between 870 mgC m−3 in May and 580 mgC m−3 in September, coinciding with the period of maximum dead organic matter and phytoplankton biomass concentrations. The results of the numerical simulations are in good agreement with observed values. The difference between the modelled and observed POC concentrations is equal to 3–28% and depends on the month for which the calculations were made, although no time trend of the difference is observed. The conclusion is that the numerical simulations are a ufficiently good reflection of POC dynamics in the Baltic.
Źródło:
Oceanologia; 2010, 52, 4
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Flow, waves and water exchange in the Suur Strait, Gulf of Riga, in 2008
Autorzy:
Raudsepp, U.
Laanemets, J.
Haran, G.
Alari, V.
Pavelson, J.
Kouts, T.
Powiązania:
https://bibliotekanauki.pl/articles/49038.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
flow
wave
water exchange
Suur Strait
Riga Gulf
modelling
shear velocity
Baltic Sea
wind
wind condition
storm
wave heigh
sediment
seasonal cycle
horizontal distribution
outflow
Opis:
Wind, flow and wave measurements were performed in November–December in 2008 in the relatively narrow and shallow Suur Strait connecting the waters of the V¨ainameri and the Gulf of Riga. During the measurement period wind conditions were extremely variable, including a severe storm on 23 November. The flow speed along the strait varied between ±0.2 m s−1, except for the 0.4 m s−1 that occurred after the storm as a result of the sea level gradient. The mean and maximum significant wave heights were 0.53 m and 1.6 m respectively. Because of their longer fetch, southerly winds generated higher waves in the strait than winds from the north. All wave events caused by the stronger southerly winds induced sediment resuspension, whereas the current-induced shear velocity slightly exceeded the critical value for resuspension only when the current speed was 0.4 m s−1. A triplenested two-dimensional high resolution (100 m in the Suur Strait) circulation model and the SWAN wave model were used to simulate water exchange in 2008 and the wave-induced shear velocity field in the Suur Strait respectively. Circulation model simulations demonstrated that water exchange was highly variable, that cumulative transport followed an evident seasonal cycle, and that there was an gross annual outflow of 23 km3 from the Gulf of Riga. The horizontal distribution of waveinduced shear velocity during the strong southerly wind event indicated large shear velocities and substantial horizontal variability. The shear velocities were less than the critical value for resuspension in the deep area of the Suur Strait.
Źródło:
Oceanologia; 2011, 53, 1
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Variability of the marine boundary layer parameters over Baltic Sea sub-basins and their impact on nitrogen deposition
Autorzy:
Hongisto, M.
Powiązania:
https://bibliotekanauki.pl/articles/48086.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
Baltic Sea
biological production
brackish water
carbon cycle
inorganic nitrogen
marine area
marine boundary layer
meteorological measurement
nitrogen deposition
reactive nitrogen species
seasonal deposition
terrestrial area
variability
Opis:
The variability of the marine boundary layer parameters over the Baltic Sea and its sub-basins and their impact on the 6 h, monthly or seasonal deposition of oxidized nitrogen compounds was studied using results of the Hilatar chemistrytransport model, the 6th hour forecasts of the HIRLAM weather prediction model and meteorological measurement data. The monthly load of oxidized nitrogen was highest in the winters of 1993–1995 and 2000, and lowest in 1996–1997 and 2005; no trend was detected. Short-time correlations were low, but a significant correlation of the monthly deposition with the NAO index and ice-season was found over northern sub-basins.
Źródło:
Oceanologia; 2011, 53, (1-TI)
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-5 z 5

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