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Wyszukujesz frazę "Falkowska, L." wg kryterium: Autor


Wyświetlanie 1-8 z 8
Tytuł:
12-hour cycle of matter transformation in the sea surface microlayer in the offshore waters of the Gdańsk Basin (Baltic Sea) during spring
Autorzy:
Falkowska, L.
Powiązania:
https://bibliotekanauki.pl/articles/48216.pdf
Data publikacji:
2001
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
nutrient
matter transformation
spring
sea water
Baltic Sea
microlayer
sea surface
Gdansk Basin
Opis:
Short-term measurements of nutrient and DOC concentrations and suspended matter (particles, chlorophyll a, phaeophytin, algae and ATP concentrations) carried out in seawater layers of varying thickness (10, 90, 250 μm and the underwater layer – 15 cm depth) in spring form the basis for a discussion of the diurnal fluctuations of nutrient and suspended organic matter concentrations. Quantitative and qualitative differences in the composition of neuston species were recorded in selected sub-layers of the chemically stratified sea surface microlayer. The non-linear regression equation was applied in a mathematical model of the diurnal fluctuations of nutrients and organic matter. Two maxima and two minima were found in the diurnal cycle of nutrient concentrations and organic suspensions in sub-layers of different thickness selected from the sea surface. The first maximum, expressed by the proliferation of phytoneuston, lasted from the very early morning till mid-morning. The second maximum occurred in the afternoon. The chlorophyll a concentration, and ATP and neuston abundance declined markedly around noon, when the biologically-damaging radiation dose increased, compelling the downward migration of organisms. At the same time, the photo-oxidation of dissolved organic matter intensified and the concentrations of inorganic forms of nitrogen and phosphorus rose. A shift (up to 2 h) between the maximum and minimum neuston concentration in these sea surface layers was indicative of phototaxis occurring within the entire surface microlayer and in the underwater layer. After sunset the decline in phytoneuston abundance could be related to zooplankton grazing as well as to respiratory breakdown.
Źródło:
Oceanologia; 2001, 43, 2
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Selected ionic components of the marine aerosol over the Gulf of Gdańsk
Autorzy:
Nadstazik, A.
Falkowska, L.
Powiązania:
https://bibliotekanauki.pl/articles/48208.pdf
Data publikacji:
2001
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
Gdansk Deep
aerosol origin
coastal station
Hel
Gdansk Gulf
marine aerosol
macroelement
nitrate
chloride loss
Opis:
Aerosol samples were collected in May 1997 at a routine off-shore measurement station in the Gdańsk Deep region and at Hel, the latter being a coastal station situated at the tip of the Hel Peninsula. Concentrations of NO− 3 , Cl−, Na+, Mg2+, K+ and Ca2+ were measured simultaneously at both stations. The sea influences the chemical composition of aerosols in the coastal zone of the Gulf of Gdańsk regardless of season, time of day or direction of advection. Sodium chloride was always present in aerosols in the form of large particles originating from seawater. Besides the marine chloride and nitrate, additional amounts of these ions could have been of terrigenous origin. Sodium and chloride concentrations were dominant in the total mass of aerosols at both stations; however, these concentrations were three times higher at the marine station. Similarly, the concentrations of ions originating from seawater, like magnesium and calcium, were, on average, three times higher at the marine station. The chemical composition of aerosols and air over the Gulf of Gdańsk was modified through the evaporation of chloride from the marine salt particles in reactions with gaseous nitric and sulphuric acids. A certain deficit of chloride versus sodium ions was noted. At the marine station the Cl−/Na+ ratio reached 0.89 ± 0.2, on average, while over the land station it was 0.93 ± 0.25, i.e. lower than the seawater standard.
Źródło:
Oceanologia; 2001, 43, 1
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Sulphates in particles of different sizes in the marine boundary layer over the Southern Baltic Sea
Autorzy:
Falkowska, L.
Lewandowska, A.
Powiązania:
https://bibliotekanauki.pl/articles/48464.pdf
Data publikacji:
2004
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
coastal zone
marine boundary layer
sulphate
aerosol
concentration
Baltic Sea
Opis:
Concentrations of sulphate ions and particle size distributions were measured in the marine boundary layer using a ten-cascade Berner impactor at Hel between December 1997 and March 1998, and with a filter packin Gdynia from February to May 2001. In the marine boundary layer over the Hel Peninsula the presence of natural sea-salt and non-sea-salt sulphate ions (nssSO4 2−) was confirmed in the aerosols. The nssSO4 were present in all size ranges only in December 1997 and in the first half of January 1998, making up an average of 83.7±2.4% of the total sulphate content. In the other winter months, nssSO4 2− were recorded only in aerosols of diameters from 0.4 to 1.5 μm, and their average contribution dropped by over 20%. The extended growing season in the Southern Baltic resulted in the formation of fine particles that appeared in the marine boundary layer in early winter. At that time the proportion of nssSO4 2− in ultra-fine particles ranged from 75.7% to 100%. The concentration of nssSO4 2−, which varied from 0.8 to 2.3 nmol m−3 in particles < 0.4 μm in size probably constituted the natural background aerosol population in the relatively clean coastal environment of the Southern Baltic Sea. In the coastal urbanised area of Gdynia, the sulphate concentration in aerosols was higher than at Hel (av. 75.3 nmol m−3) but the proportion of nssSO4 was low, of the order of 24%. Sea salt was then the dominant source of sulphate.
Źródło:
Oceanologia; 2004, 46, 2
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ammonia and ammonium over the Southern Baltic Sea. Part 1. Preparation of aerosol and air samples for the determination of ammonia by the indophenol method
Autorzy:
Lewandowska, A.
Falkowska, L.
Powiązania:
https://bibliotekanauki.pl/articles/47640.pdf
Data publikacji:
2004
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
coastal zone
aerosol sample
ammonium
aerosol preparation
air sample
ammonia
Baltic Sea
indophenol method
climate change
Opis:
1997 saw the start of a study into the spatial and temporal changes in the chemical composition of the atmosphere over the littoral and offshore waters of the Baltic Sea. Collection of samples and their subsequent chemical analysis was preceded by meticulous laboratory experiments concerning the validation and adaptation of the analytical procedures. The colorimetric indophenol blue technique was used to analyse the aerosol samples for the concentration of ammonium ions and the air samples for their gaseous ammonia. The samples were collected with PTFE-filters and Whatman 41 filters coated with 5% orthophosphoric acid. This acid enhances the aerosol sampling efficacy but reduces the pH of the reaction in which indophenol is formed. The pH of the aerosol samples thus had to be raised, and this in turn required an alteration to the original procedure prior to ammonia determination. It was demonstrated that the addition of 0.1 N KOH to the filters coated with H3PO4 increases the pH of the reaction medium to the required level of pH = 8–11.5 and does not substantially influence the precision of the determination; the error of the modified procedure was of the order of 5.2%. Air samples for the determination of gaseous ammonia were collected with annular denuders. Oxalic acid and citric acid are the usual impregnating agents. In the present experiments oxalic acid was used for denuder impregnation; it turned out to be more effective than citric acid under the conditions of the southern Baltic Sea. The detection limit of the indophenol blue method in these laboratory experiments was 0.045 mmol dm−3. The respective relative standard deviations (RSD) within the range of higher and lower concentrations were 0.64% and 4.53%.
Źródło:
Oceanologia; 2004, 46, 2
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ammonia and ammonium over the Southern Baltic Sea. Part 2. The origin of ammonia and ammonium over two coastal stations: Gdynia and Hel
Autorzy:
Lewandowska, A.
Falkowska, L.
Beldowska, M.
Powiązania:
https://bibliotekanauki.pl/articles/48111.pdf
Data publikacji:
2004
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
coastal zone
Gdynia
aerosol
ammonium
ammonia
concentration
Hel Peninsula
Baltic Sea
Opis:
Ammonia concentrations in aerosols and ammonium concentrations in the air were measured in the coastal zone of the southern Baltic Sea. The main study area was the Hel Peninsula, where measurements were carried out from December 1997 to March 1998. There was a second such area in Gdynia, where the first measurement period extended from May to December 2000, and the second one lasted from February to May 2001. At the same time, chloride, sulphate and sodium concentrations in the aerosols were determined; meteorological parameters were also measured. Aerosol samples were collected with a filter pack, and the gaseous phase species were collected on denuders. At both stations, the ammonium concentration in aerosols was at least one order of magnitude higher than that of the ammonia in the air samples. It was found that the marine boundary layer always contained ammonium chloride and ammonium sulphate. The presence of ammonium nitrate was detected only when winds were slight and was attributed to local anthropogenic sources. The ammonia concentration related to nitrate increased with rising air humidity and a falling temperature. The contribution of marigenic ions in aerosols was noted at onshore wind of speeds > 3.5 m s−1. In winter as in summer, conditions occurred facilitating light backscattering by a ‘wet’ aerosol, which contained ammonium nitrate and ammonium sulphate in proportions of 2.5:1 and 1:1.
Źródło:
Oceanologia; 2004, 46, 2
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Adenosine triphosphate in the marine boundary layer in the Southern Baltic Sea
Autorzy:
Pryputniewicz, D.
Falkowska, L.
Burska, D.
Powiązania:
https://bibliotekanauki.pl/articles/48770.pdf
Data publikacji:
2002
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
organic matter
marine boundary
adenosine triphosphate
coastal water
vertical distribution
spring
microlayer
Baltic Sea
marine ecosystem
Opis:
Changes in adenosine triphosphate (ATP) concentration were measured in the offshore and coastal waters of the GdańskBasi n in spring. As regards the vertical distribution, it was found that high ATP concentrations occurred mainly in the euphotic layer (above the thermocline) and near the bottom (below the halocline). The high concentrations of ATP in the euphotic layer resulted from primary and secondary production, while the other maximum was due to the presence of bacteria actively degrading organic matter. Changes in ATP concentration in the euphotic layer were closely correlated with the phase of the day. An increase in ATP concentrations in the surface microlayer was observed in the evening and at night, probably as a result of heterotroph proliferation. During daylight, ATP production was inhibited by increasing radiation, hence its concentrations in the sea surface microlayer were considerably lower. Strong winds exerted a significant influence on ATP concentrations in the surface microlayer and in the subsurface water. Windstress depressed ATP concentrations. The biomass of living microorganisms in the microlayer was comparable with the microbiomass beneath the halocline.
Źródło:
Oceanologia; 2002, 44, 4
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Stratification of particulate organic carbon and nitrogen in the Gdańsk Deep (Southern Baltic Sea)
Autorzy:
Burska, D.
Pryputniewicz, D.
Falkowska, L.
Powiązania:
https://bibliotekanauki.pl/articles/47610.pdf
Data publikacji:
2005
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
stratification
Gdansk Deep
nitrogen
particulate organic carbon
carbon
particulate organic nitrogen
flux
Baltic Sea
Opis:
Particulate organic carbon (POC) and nitrogen (PON) concentrations and fluxes were measured during an experiment in the Gdańsk Deep in late spring (30.05. –06.06.2001). The vertical POC and PON concentration profiles were characterised by the highest values in the euphotic layer,a gradual decrease with depth, and an increase below the halocline. The hydrophysical conditions had a decisive impact on POC and PON fluxes in the water column. Preferential removal of nitrogen from suspended mater was observed in the entire water column (maximum – in the vicinity of thermocline). There were also differences in the diurnal effectiveness of nitrogen removal as compared to carbon removal. The removal rate was highest at night.
Źródło:
Oceanologia; 2005, 47, 2
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Diurnal variations in nitrogen, phosphorus and iron compounds in the Southern Baltic Sea
Autorzy:
Sikorowicz, G.
Falkowska, L.
Burska, D.
Dunajska, D.
Pryputniewicz, D.
Magulski, R.
Lewandowska, A.
Powiązania:
https://bibliotekanauki.pl/articles/47649.pdf
Data publikacji:
2005
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
iron
nutrient
Gdansk Deep
nitrogen
density stratification
diurnal variation
Baltic Sea
oxygen condition
phosphorus
Opis:
In order to assess their short-term variability, nutrient concentrations were measured at standard depths at 2 h intervals in the deepest region of the Gdańsk Deep during the first ten days of June 2001. The mean concentrations of nutrients in the euphotic zone were: NN (NO2 −, NO3 −, NH4 +) – 1.93 μmol dm−3, PO4 3− – 0.12 μmol dm−3 and Fetot – 0.11 μmol dm−3. During daylight hours, when the rate of assimilation was fastest, concentrations of nitrogen, phosphorus and iron compounds were very low. The phosphate concentration fell to a minimum (0.03 μmol dm−3) between 04:00 and 10:00 hrs, while total iron dropped to 0.01 μmol dm−3 between 10:00 and 16:00 hrs. Both levels were below the limiting values for phosphorus and iron. At night, concentrations of NO3 − and PO4 3− rose by 25%, those of NH4 + and Fetot by 35%. The mean molar ratios of NN:PO4 3− and Fetot:PO4 3− in the surface layer were subject to significant daily fluctuations. The molar NN:PO4 3− ratio was higher than the optimum value established for the Baltic Sea. Below the halocline, the concentrations of dissolved iron and phosphorus rose as a result of diffusion from sediments in response to changing redox conditions.
Źródło:
Oceanologia; 2005, 47, 2
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-8 z 8

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