Dynamics of phytoplankton groups in estuarine area of Oued River (Mazafran, Algeria)

2020 ◽  
Vol 10 (5) ◽  
pp. 16-25
Author(s):  
B. Boudjenah ◽  
Z. Mokrane ◽  
Z. Mokrane
Keyword(s):  
Physicochemical Parameters ◽  
High Salinity ◽  
River Mouth ◽  
Large Temperature ◽  
Phytoplankton Species ◽  
Low Oxygen ◽  
Freshwater Environment ◽  
Estuarine Zone ◽  
Environmental Variations ◽  
Low Oxygen Concentration

Estuaries are the contact areas between fresh and sea waters. These areas are very unstable ecosystems, and the hydrological. physicochemical parameters are extremely variable. Phytoplankton is a very important part of ecosystem and is extremely susceptible to environmental variations. Throughout this analysis we propose to assess a distribution of phytoplankton groups in an estuarine zone (the mouth of Oued Mazafran). and to establish distributions along the adjacent coast as a function of time and space concerned. Hydrological and phytoplankton samples were taken in 04 stations which were located in the region of (Oued Mazafran) from the period (17 January to 18 April) of 2018. The results of salinity, temperature, abundance, diatoms, diatom index and specific richness allow us to say: Stations 1 and 2: (Colonel Abbas beach and river mouth) we have the river's transition ecosystem with a high salinity variations from 16.32 to 30.33 at Station 2. and from 30.08 to 36.86 at Station 1. We note the presence of euryhaline species. Station 3: A freshwater environment (Mazafran Oued) salinities of 0.8 with a large temperature range of 12 to 18 °C and low oxygen concentration of 1.33 mg.dm-3 we have Phytoplankton species of freshwater.Stations 4: Seawater ecosystem with little variation (shellfish center). During this time the specific wealth reported at all stations is 343 species; we have 68.8 per cent of diatom. Station 3 (Oued Mazafran) registered its highest cell density of 11370 cell.dm-3.

Effect of low oxygen concentration on activation of inflammation by Helicobacter pylori

2021 ◽  
Vol 560 ◽  
pp. 179-185
Author(s):  
Adiza Abass ◽  
Tokuju Okano ◽  
Kotchakorn Boonyaleka ◽  
Ryo Kinoshita-Daitoku ◽  
Shoji Yamaoka ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Oxygen Concentration ◽  
Low Oxygen ◽  
Low Oxygen Concentration

Thermogravimetric and infrared spectral analysis of candle coal pyrolysis under low-oxygen concentration

2021 ◽  
Vol 696 ◽  
pp. 178840
Author(s):  
Liangzhou Chen ◽  
Xuyao Qi ◽  
Jian Yang ◽  
Haihui Xin
Keyword(s):  
Spectral Analysis ◽  
Oxygen Concentration ◽  
Coal Pyrolysis ◽  
Low Oxygen ◽  
Infrared Spectral ◽  
Low Oxygen Concentration

The Constant Low Oxygen Concentration in All the Target Cells for Mouse Tail Radionecrosis

1982 ◽  
Vol 92 (1) ◽  
pp. 172 ◽  
Author(s):  
J. H. Hendry ◽  
J. V. Moore ◽  
B. W. Hodgson ◽  
J. P. Keene
Keyword(s):  
Oxygen Concentration ◽  
Target Cells ◽  
Low Oxygen ◽  
Low Oxygen Concentration

scholarly journals Simultaneous Nitrification and Denitrification in an SBR with a Modified Cycle During Reject Water Treatment

2013 ◽  
Vol 39 (1) ◽  
pp. 83-91 ◽  
Author(s):  
Katarzyna Bernat
Keyword(s):  
Batch Reactor ◽  
Anaerobic Sludge ◽  
Simultaneous Nitrification And Denitrification ◽  
Low Oxygen ◽  
Total Removal ◽  
Operational Conditions ◽  
Reject Water ◽  
Do Concentration ◽  
Nitrification And Denitrification ◽  
Low Oxygen Concentration

Abstract In this study, the dependence between volumetric exchange rate (n) in an SBR (Sequencing Batch Reactor) with a modified cycle and simultaneous nitrification and denitrification (SND) efficiency during the treatment of anaerobic sludge digester supernatant was determined. In the SBR cycle alternating three aeration phases (with limited dissolved oxygen (DO) concentration up to 0.7 mg O2/L) and two mixing phases were applied. The lengths of each aeration and mixing phases were 4 and 5.5 h, respectively. Independently of n, a total removal of ammonium was achieved. However, at n = 0.1 d-1 and n = 0.3 d-1 nitrates were the main product of nitrification, while at n = 0.5 d-1, both nitrates and nitrites occurred in the effluent. Under these operational conditions, despite low COD/N (ca. 4) ratio in the influent, denitrification in activated sludge was observed. A higher denitrification efficiency at n = 0.5 d-1 (51.3%) than at n = 0.1 d-1 (7.8%) indicated that n was a crucial factor influencing SND via nitrite and nitrate in the SBR with a low oxygen concentration in aeration phases.

Succinate Metabolism of Isolated Soybean Nodule Bacteroids at Low Oxygen Concentration

1986 ◽  
Vol 50 (4) ◽  
pp. 1009-1014
Author(s):  
Shigeyuki Tajima ◽  
Isao Kimura ◽  
Hiroyuki Sasahara
Keyword(s):  
Oxygen Concentration ◽  
Low Oxygen ◽  
Soybean Nodule ◽  
Low Oxygen Concentration

scholarly journals Zooplankton fluctuations in Jurumirim Reservoir (São Paulo, Brazil): a three-year study

2009 ◽  
Vol 69 (1) ◽  
pp. 1-18 ◽  
Author(s):  
LP. Sartori ◽  
MG. Nogueira ◽  
R. Henry ◽  
EM. Moretto
Keyword(s):  
Water Column ◽  
Oxygen Concentration ◽  
Retention Time ◽  
Sao Paulo ◽  
Seasonal Effect ◽  
São Paulo ◽  
Low Oxygen ◽  
High Concentration ◽  
Heterogeneous Distribution ◽  
Low Oxygen Concentration

During three consecutive years, monthly samples of zooplankton were taken in the lacustrine (dam) zone of Jurumirim (São Paulo, Brazil). The seasonal effect on basic limnological features (thermal regime, oxygen distribution, phytoplankton biomass, etc.) was also examined. The influence of the seasonality on the fluctuation of the zooplankton composition and abundance was not clearly detected (low degree of recurrent patterns). Rotifers (32 taxa) were the most abundant organisms during almost the entire study period with some seasonal alternations in the maximum abundance peaks of the main taxa (Conochilus unicornis, Keratella americana, K. cochlearis and Hexarthra spp.), except for Polyarthra (mainly P. vulgaris). Only occasionally copepods were numerically dominant. Higher copepod abundance was positively associated to periods of increase in the water retention time. Among the Copepoda (10 taxa) the calanoids (mainly Notodiaptomus iheringi) were more abundant, especially in warmer periods. Conversely, cyclopoids had higher abundance in autumn and winter. The species Thermocyclops minutus and T. decipiens co-occurred, but the first attained higher abundance. Some evidence of co-existence strategies between both species are considered. Cladocera (17 taxa) was never numerically dominant and the main taxa (Bosmina spp., Ceriodaphnia spp. and Diaphanosoma spp.) occurred almost the whole study period and did not present a seasonal pattern of fluctuation. Diaphanosoma (mainly D. birgei) attained the highest abundance among cladocerans. Most organisms were always found at the surface, but they also occupy the whole water column, even in periods of stratified conditions and low oxygen concentration in the bottom layers. Among the main zooplanktonic taxa, only Hexarthra avoids deep layers. An exceptionally high concentration of Copepoda nauplii on the surface was influenced by low transparency, high concentration of phytoplankton at this layer and low oxygen concentration at the bottom. In periods of higher retention timevariability there was a more heterogeneous distribution of the zooplankton in the water column. The increase in the retention time seems also to favor the copepod development. Finally, some inter-decade changes are considered on the basis of zooplankton assemblage structure observations.

Effect of low oxygen concentration on the oxidation behavior of Ni-based alloys 625 and 825 in supercritical water

2018 ◽  
Vol 131 ◽  
pp. 1-10 ◽  
Author(s):  
Jianqiao Yang ◽  
Shuzhong Wang ◽  
Xingying Tang ◽  
Yuzhen Wang ◽  
Yanhui Li
Keyword(s):  
Oxygen Concentration ◽  
Supercritical Water ◽  
Oxidation Behavior ◽  
Low Oxygen ◽  
Low Oxygen Concentration

scholarly journals Hypoxic-response elements in the oncolytic parvovirus Minute virus of mice do not allow for increased vector production at low oxygen concentration

2006 ◽  
Vol 87 (5) ◽  
pp. 1197-1201 ◽  
Author(s):  
Charlotte Servais ◽  
Perrine Caillet-Fauquet ◽  
Marie-Louise Draps ◽  
Thierry Velu ◽  
Yvan de Launoit ◽  
...  
Keyword(s):  
Cell Metabolism ◽  
Consensus Sequence ◽  
High Titre ◽  
Host Cells ◽  
Low Oxygen ◽  
Minute Virus Of Mice ◽  
Minute Virus ◽  
Responsive Element ◽  
Low Oxygen Concentration

Vectors derived from the autonomous parvovirus Minute virus of mice, MVM(p), are promising tools for the gene therapy of cancer. The validation of their in vivo anti-tumour effect is, however, hampered by the difficulty to produce high-titre stocks. In an attempt to increase vector titres, host cells were subjected to low oxygen tension (hypoxia). It has been shown that a number of viruses are produced at higher titres under these conditions. This is the case, among others, for another member of the family Parvoviridae, the erythrovirus B19 virus. Hypoxia stabilizes a hypoxia-inducible transcription factor (HIF-1α) that interacts with a ‘hypoxia-responsive element’ (HRE), the consensus sequence of which (A/GCGTG) is present in the B19 and MVM promoters. Whilst the native P4 promoter was induced weakly in hypoxia, vector production was reduced dramatically, and adding HRE elements to the P4 promoter of the vector did not alleviate this reduction. Hypoxia has many effects on cell metabolism. Therefore, even if the P4 promoter is activated, the cellular factors that are required for the completion of the parvoviral life cycle may not be expressed.

Controlled Low Oxygen Concentration by Venturi Effect

JAMA ◽  
1971 ◽  
Vol 216 (8) ◽  
pp. 1351
Author(s):  
E. Leslie Chusid
Keyword(s):  
Oxygen Concentration ◽  
Low Oxygen ◽  
Venturi Effect ◽  
Low Oxygen Concentration
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