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Wyszukujesz frazę "diatom" wg kryterium: Temat


Wyświetlanie 1-5 z 5
Tytuł:
Spatio-temporal variation of microphytoplankton in the upwelling system of the South-Eastern Arabian Sea during the summer monsoon of 2009
Autorzy:
Thomas, L.C.
Padmakumar, K.B.
Smitha, B.R.
Asha Devi, C.R.
Nandan, S.B.
Sanjeevan, V.N.
Powiązania:
https://bibliotekanauki.pl/articles/49085.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
Arabian Sea
upwelling
coastal water
phytoplankton
chlorophyll a
diatom
centric diatom
spatio-temporal variability
microphytoplankton
Chaetoceros
Źródło:
Oceanologia; 2013, 55, 1
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Phytoplankton response to changes of physicochemical variables in Lake Nasser, Egypt
Autorzy:
Hussian, A.-E. M.
Napiorkowska-Krzebietke, A.
Toufeek, M.E.F.
El-Monem, A.M.A.
Morsi, H.H.
Powiązania:
https://bibliotekanauki.pl/articles/961602.pdf
Data publikacji:
2015
Wydawca:
Uniwersytet Warmińsko-Mazurski w Olsztynie / Polskie Towarzystwo Magnezologiczne im. Prof. Juliana Aleksandrowicza
Tematy:
phytoplankton
density
physicochemical variation
nutrient
chlorophyll a
diatom
Lake Nasser
Egypt
Opis:
Seasonal and spatial changes of phytoplankton in relation to environmental variables affecting the water quality were investigated along the main channel of Lake Nasser throughout 2013. In total, 104 phytoplankton species, belonging to 7 classes, were identified. Phytoplankton assemblages were dominated by Bacillariophyceae, Cyanophyceae and Chlorophyceae, whereas Dinophyceae, Euglenophyceae, Chrysophyceae and Cryptophyceae were infrequent. Cyclotella glomerata, C. ocellata and Aulacoseira granulata represented the most abundant species among Bacillariophyceae. Cyanophyceae was dominated by Planktolyngbya limnetica and Eucapsis minuta, and Chlorophyceae by Ankistrodesmus fusiformis and Staurastrum paradoxum. The water column was thermally stratified during summer, while being mixed throughout winter. Phytoplankton features and physicochemical variables were analyzed with the principal component analysis. Electrical conductivity and water temperature were the most common factors negatively controlling phytoplankton density. Phytoplankton density was positively associated with NO3, whereas it was negatively correlated with PO4 and HCO3. Cyanophyceae were strongly adapted to the environmental variables and NO2 was limiting their growth. Chlorophyceae were more dependent on PO4 than NO3. The vertical distribution of Chl a was associated with the summer thermal stratification and its concentration increased southwards. Chl a was affected by NO2 and linked to Chlorophyceae. The regional variations of phytoplankton reflected its response to varying environmental conditions. The annual average of the trophic state index indicated eutrophic waters of Lake Nasser.
Źródło:
Journal of Elementology; 2015, 20, 4
1644-2296
Pojawia się w:
Journal of Elementology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of iron limitation on cells of the diatom Cyclotella meneghiniana Kützing
Autorzy:
Lewandowska, J.
Kosakowska, A.
Powiązania:
https://bibliotekanauki.pl/articles/47921.pdf
Data publikacji:
2004
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
iron
chlorophyll a
cell
Cyclotella meneghiniana
protein
aquatic ecosystem
Baltic Sea
growth
diatom
limitation
Opis:
The response of the Baltic diatom Cyclotella meneghiniana to iron deficiency was examined. The following growth parameters were measured: cell number, chlorophyll a and protein content. The results demonstrate the ability of this diatom to grow well with minimal iron availability; however, the rate of growth fell markedly at the lowest iron(III) concentration. The results of spectrophotometric chlorophyll a measurements and protein assays using the Lowry and Bradford methods indicated a significant decrease in their quantities. Iron may therefore be an important regulatory factor controlling the growth of diatom C. meneghiniana in an aquatic ecosystem.
Źródło:
Oceanologia; 2004, 46, 2
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effects of oxytetracycline on growth and chlorophyll a fluorescence in green algae (Chlorella vulgaris), diatom (Phaeodactylum tricornutum) and cyanobacteria (Microcystis aeruginosa and Nodularia spumigena)
Autorzy:
Siedlewicz, G.
Zak, A.
Sharma, L.
Kosakowska, A.
Pazdro, K.
Powiązania:
https://bibliotekanauki.pl/articles/2079298.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
oxytetracycline
microalga
chlorophyll a
fluorescence
green alga
Chlorella vulgaris
diatom
Phaeodactylum tricornutum
Cyanoprokaryota
Microcystis aeruginosa
Opis:
The study aimed at measuring the influence of a wide range of oxytetracycline concentrations, with particular attention to the low levels of the antibiotic on cyanobacteria Microcystis aeruginosa and Nodularia spumigena, diatom Phaeodactylum tricornutum and the model green algae Chlorella vulgaris by conducting prolonged toxicity tests (lasting 10 days). Standard measurements (cell number, optical density, chlorophyll a concentration) were combined with photosynthetic parameters measurements. The obtained results show that concentrations of oxytetracycline present in the environment can affect tested microorganisms. It was found to decrease photosystem II efficiency and disrupt the photosynthesis process. A careful interpretation of photosynthetic parameters allowed a better understanding of the mode of action of oxytetracycline in relation to non-target photoautotrophic organisms like cyanobacteria and microalgae. In conclusion, it would appear that the use of standard chronic toxicity tests (72 h) does not allow to accurately and reliably assess the chronic impact of bioactive compounds including drugs and their metabolites on water organisms. On this basis, we recommend the application of extended duration tests.
Źródło:
Oceanologia; 2020, 62, 2; 214-225
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Characterization of phytoplankton size-structure based productivity, pigment complexes (HPLC/CHEMTAX) and species composition in the Cochin estuary (Southwest coast of India): special emphasis on diatoms
Autorzy:
Paul, M.
Valappan, M.N.
Nanappan, U.
Gopinath, V.
Velloth, R.T.
Rajendran, A.
Nair, M.
Peariya, A.
Powiązania:
https://bibliotekanauki.pl/articles/2078766.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
phytoplankton
size structure
photopigment
species composition
diatom
chlorophyll a
primary production
seasonality
high performance liquid chromatography
chemotaxonomy
India
Opis:
Seasonal studies on size-fractionated phytoplankton productivity (biomass and primary production), marker pigments, and species composition and abundance were carried out in the Cochin estuary (CE), located on the southwest coast of India, to identify the critical environmental factors that control the consistent preponderance of diatoms. The overall results of the study showed a significant contribution of small-sized phytoplankton, specifically nanophytoplankton (2—20 μm), to the total chlorophyll a and primary production in the estuary, regardless of seasons. Diatoms constituted the major phytoplankton taxa, showed an exceptional seasonal scale increase in numerical abundance during the post-southwest monsoon. The relative increase in fucoxanthin (biomarker of diatoms) over other marker pigments substantiated the numerical dominance of diatoms throughout the sampling periods. This is the first study in the CE in which phytoplankton marker pigments have been detected and elucidated the seasonality of functional groups based on HPLC/chemotaxonomy analytical approaches. The prevalence of high DiatDP and diatom chlorophyll a equivalent (estimated by CHEMTAX), further confirmed the preponderance of diatoms in the CE, despite the intermittent dominance of cyanophytes and cryptophytes (monsoon period). The consistent increase in SPM levels (> 25 mg L—1), established at all sampling stations, indicated that the water column turbidity might be one of the significant environmental factors hindering the growth of large-sized phytoplankton (ca. >20 μm) in the CE even if the system invariably holds high inorganic nutrients, irrespective of seasons
Źródło:
Oceanologia; 2021, 63, 4; 463-481
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-5 z 5

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