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Wyszukujesz frazę "phosphorus nutrient" wg kryterium: Temat


Wyświetlanie 1-9 z 9
Tytuł:
Modelling nitrogen and phosphorus limitation on phytoplankton growth in Narva Bay, South-Eastern Gulf of Finland
Autorzy:
Lessin, G.
Lips, I.
Raudsepp, U.
Powiązania:
https://bibliotekanauki.pl/articles/47604.pdf
Data publikacji:
2007
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
nitrogen
Finland Gulf
numerical modelling
Narva Bay
nutrient limitation
phytoplankton
phosphorus
Opis:
The relative roles of nitrogen and phosphorus in the limitation of phytoplankton growth in Narva Bay, south-eastern Gulf of Finland, were studied by combining the results of numerical modelling and nutrient enrichment experiments.Mo delled biomass-based intracellular nutrient concentrations (nutrient functions) were used to estimate the limiting nutrient in Narva Bay.Nutr ient functions – NF ∈ [0; 1] for nitrogen and PF ∈ [0; 1] for phosphorus – define the dependence of the phytoplankton growth rate on nutrients: NF = PF = 1 corresponds to nonlimitation of phytoplankton growth by nutrients, whereas NF = 0 or PF = 0 to zero growth.T he biotests indicated the response of phytoplankton growth to an increase in nutrient concentration in the surrounding water.Thr ee locations were selected for detailed analyses of temporal variations in the nutrient functions: the offshore station N12, station N8 at the mouth of the River Narva, and coastal station 38.T he biotests were performed at the same stations. NF and PF reached values of 0.9 prior to the spring bloom. With the onset of the spring bloom, NF decreased rapidly and remained below 0.1 in the open part of Narva Bay for the rest of that period.I n the coastal zone, NF was in excess of 0. 1, with a local maximum in the river mouth area. PF decreased to 0.3–0.4 in the open bay after the spring bloom.I n the coastal zone PF remained above 0.4, with a certain increase from the midsummer minimum towards the end of summer.The numerical modelling results clearly show that nitrogen limits phytoplankton growth in Narva Bay.Ph osphorus limitation may occur only for a limited period and over a limited area at the Narva River mouth and other coastal locations.I n general, the biotests backed up the modelling results, the main exception being in the open bay during summer.The model does not account for nitrogen fixation, however.S ince N-fixing cyanobacteria were prevalent in the offshore area, the addition of phosphorus led to enhanced phytoplankton growth at station N12.
Źródło:
Oceanologia; 2007, 49, 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
Tytuł:
Deposition of organic matter and particulate nitrogen and phosphorus at the North Sea - Baltic Sea transition - a GIS study
Autorzy:
Jansen, D.L.
Lundqvist, D.P.
Christiansen, C.
Lund-Hansen, L.C.
Balstrom, T.
Leipe, T.
Powiązania:
https://bibliotekanauki.pl/articles/48457.pdf
Data publikacji:
2003
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
organic matter
nutrient
deposition
nitrogen
Baltic Sea
sediment
phosphorus
North Sea
Geographic Information System
Opis:
A GIS (Geographical Information System) based study on deposition in the North Sea – Baltic Sea transition area has been carried out. The study is based on (i) a digital bathymetry model, (ii) 93 available 210Pb/137Cs sedimentation rate estimations, (iii) grain-size distributions, organic matter, C, N and P content of 64 top 1 cm sediment samples from the study area, and (iv) GIS-based modelling of resuspension potentials based on wind statistics. With the use of regression statistics on depth, resuspension potential and sediment characteristics, results are extrapolated area-wide from the 64 sampling positions. The area is divided into sediment types and classified as accumulation or erosion/transport bottoms. Model results show good agreement with existing maps of sediment distributions, indicating that the sediment distribution is governed to a large extent by windinduced waves. Correlations of sediment types, their deposition rates and their N and P contents were used to estimate spatial deposition rates. In all, the yearly deposition in the study area amounts to 2.8 million tons of organic matter, 0.14 million tons of total nitrogen, and 0.035 million tons of total phosphorus. Correlations of sediment types and dry bulk densities were used to infer spatial inventories of organic matter and total nitrogen and phosphorus in the top 1 cm of the sediments. A total of 100 million tons of organic matter, 4 million tons of total nitrogen, and 0.019 million tons of total phosphorus are contained in the top 1 cm of the sediments in the study area. In general, the deep parts of the study area with low resuspension potentials act as sinks for the fine-grained sediments and their associated particulate nutrients.
Źródło:
Oceanologia; 2003, 45, 2
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Significance of nutrient fluxes via submarine groundwater discharge in the Bay of Puck, Southern Baltic Sea
Autorzy:
Szymczycha, B.
Klostowska, Z.
Lengier, M.
Dzierzbicka-Glowacka, L.
Powiązania:
https://bibliotekanauki.pl/articles/2079294.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
nutrient flux
nitrogen
phosphorus
submarine groundwater discharge
biogeochemistry
coastal zone
Puck Bay
Southern Baltic Sea
Opis:
In this study, we collected submarine groundwater discharge (SGD) and seawater samples at six sites in the Bay of Puck, in the southern Baltic Sea, in order to estimate the nutrient distribution in groundwater affected areas. In addition, we estimated nutrient fluxes via SGD, including both fresh SGD (FSGD) and recirculated seawater SGD (RSGD), to the entire Bay of Puck. Phosphate (PO43−) concentrations varied significantly among study sites and seasons, while both ammonium (NH4+) and nitrates (NO3−) concentrations varied only seasonally. The N:P ratio indicated P limitation in most of the samples. The estimated seasonal and annual loads, via SGD, of both dissolved inorganic nitrogen (DIN; 9303 t yr−1) and PO43− (950 t yr−1), were the most significant source of nutrients to the Bay of Puck, and notably higher than quantified before (FSGD nutrient loads of 50 t yr−1 and 56 t yr−1 for DIN and PO43−, respectively). The SGD fluxes reported here indicate some of the highest rates of sediment-water fluxes reported in the Baltic Sea. These results suggest that SGD (both FSGD and RSGD) should be considered as source of chemical substances to the marine environment.
Źródło:
Oceanologia; 2020, 62, 2; 117-125
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Deposition, return flux, and burial rates of nitrogen and phosphorus in the sediments of two high-Arctic fjords
Autorzy:
Koziorowska, K.
Kulinski, K.
Pempkowiak, J.
Powiązania:
https://bibliotekanauki.pl/articles/48289.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
nitrogen
phosphorus
sediment
Hornsund region
Kongsfjorden
water column
pore water
nutrient concentration
Arctic fjord
Źródło:
Oceanologia; 2018, 60, 4
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Nodularia spumigena blooms and the occurrence of hepatotoxin in the Gulf of Gdańsk
Autorzy:
Mazur, H.
Plinski, M.
Powiązania:
https://bibliotekanauki.pl/articles/48762.pdf
Data publikacji:
2003
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
nutrient concentration
Cyanoprokaryota
water temperature
nitrogen
Nodularia spumigena
hepatotoxin
Baltic Sea
occurrence
bloom
Gdansk Gulf
phosphorus
toxin
light intensity
Opis:
Nodularia spumigena forms extensive summer blooms in the Baltic Sea. The occurrence of the blooms is determined by water temperature, light intensity and nutrient concentration; levels of nitrogen and phosphorus in particular are critical. The time of the seasonal maximum and intensity of the Nodularia bloom in the Gulf of Gdańsk vary significantly from year to year. In 2001 a rapid and massive proliferation of N. spumigena was observed in late June – early July. The concentration of nodularin in water ranged from 90 to 18 135 μg dm−3 and in lyophilised phytoplankton samples from 3000 to 3520 μg g−1 d.w. (dry weight). Such a high concentration of toxin in the recreational waters of the Gulf of Gdańsk constitutes a health risk for users of bathing areas. In 2002, the N. spumigena bloom was less dense, but lasted longer, with a maximum in late July – early August. In 2002 the concentration of nodularin did not exceed 12.6 μg dm−3 in water and 919 μg g−1 d.w. in lyophilised phytoplankton samples. Other cyanobacterial toxins – microcystins and anatoxin-a – were also detected in the coastal waters of the Gulf of Gdańsk.
Źródło:
Oceanologia; 2003, 45, 2
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
High resolution 3D-ecosystem model for the Neva Bay and Estuary - model validation and future scenarios
Autorzy:
Korpinen, P.
Kiirikki, M.
Rantanen, P.
Inkala, A.
Sarkkula, J.
Powiązania:
https://bibliotekanauki.pl/articles/48047.pdf
Data publikacji:
2003
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
biomass
water protection
St.Petersburg
chlorophyll a
phosphorus precipitation
municipal waste water
ecosystem
phytoplankton
nutrient dynamics
Neva Estuary
Neva Bay
Opis:
We have used a simple 3D-ecosystem model to describe nutrient dynamics and biomass production in the Neva Bay off St.Petersburg. The River Neva is responsible for carrying the waste waters of St. Petersburg to the Gulf of Finland. Literature values of chlorophyll-a concentrations and satellite images have been used for model validation. The results indicate that our model can reproduce both the temporal and spatial variation in the phytoplankton biomass with reasonable accuracy. The model was used to analyse scenarios describing the ecological effects of planned water protection measures. More efficient phosphorus purification was found to be the most effective measure for improving the water quality off St.Petersburg.
Źródło:
Oceanologia; 2003, 45, 1
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Biogeochemical alteration of the benthic environment by the zebra mussel Dreissena polymorpha (Pallas)
Autorzy:
Zaiko, A.
Paskauskas, R.
Krevs, A.
Powiązania:
https://bibliotekanauki.pl/articles/47856.pdf
Data publikacji:
2010
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
Baltic Sea
Curonian Lagoon
Dreissena polymorpha
benthic macroinvertebrate
biogeochemical alteration
ecosystem
mineralization
nitrogen
nutrient
oxygen consumption
phosphorus
sediment
shell
zebra mussel
Opis:
The aim of this study was to verify whether the biogeochemical features (e.g. concentration of nutrients, oxygen consumption, mineralization rate, Eh) of sediments changed by the zebra mussel or its shell deposits differ from those in the ambient soft bottom, and how these differences are related to the structure of benthic macroinvertebrates. In 2006 three sampling sessions were carried out in the Curonian Lagoon, SE Baltic Sea, at three pre-defined sites, corresponding to different bottom types: zebra mussel bed, zebra mussel shell deposits and bare soft sediments. Similarity analysis of biogeochemical parameters indicated that bottom sediments covered with zebra mussel shell deposits were rather distinct from the other bottom types because of the lowest total organic matter mineralization rate and highest organic carbon, total phosphorus and total nitrogen content. The parameters measured in the zebra mussel bed did not deviate conspicuously from the values observed in bare bottoms, except for the higher rate of oxygen consumption in the upper sediment layer. Unsuitable anoxic conditions on the one hand and the ‘attractive’ shelters provided by zebra mussels on the other hand may promote the epifaunal life style in the habitats formed by dense zebra mussel clumps.
Źródło:
Oceanologia; 2010, 52, 4
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Simulation of nutrient transport from different depths during an upwelling event in the Gulf of Finland
Autorzy:
Vali, G.
Zhurbas, V.
Laanemets, J.
Elken, J.
Powiązania:
https://bibliotekanauki.pl/articles/48984.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
Baltic Sea
ecohydrodynamic model
Finland Gulf
nutrient transport
phosphorus
phytoplankton biomass
princeton ocean model
remote sensing
simulation
upwelling
water transport
wind
wind stress
Opis:
Numerical simulation experiments with a high-resolution circulation model were carried out to study nutrient transport from different depths to the surface 10-m layer during an upwelling event along the northern coast of the Gulf of Finland in July 1999. The initial nutrient distribution is based on field measurements performed in the north-western part of the Gulf. Wind forcing covering the period of the upwelling along the northern coast was turned through 180◦ to simulate an upwelling along the southern coast. The simulation results showed that the main phosphorus transport to the upper 10-m layer occurred from depths shallower than 30 m for the upwelling events along both the northern and the southern coasts. Nitrogen transport to the upper 10-m layer was the largest from depths of 40–55 m for the upwelling along the northern and 40–65 m for the upwelling along the southern coast. Simulated cumulative volume transports to the upper 10-m layer from different depths showed that the contribution from deeper layers was larger in the case of the upwelling along the southern coast. The reduction of wind stress had a bigger influence on water transport from the deeper layers.
Źródło:
Oceanologia; 2011, 53, (1-TI)
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-9 z 9

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