Diurnal and Seasonal Changes in Distribution of Two Planktonic Ostracods, Conchoecia elegans and Conchoecia alata minor

1965 ◽  
Vol 22 (3) ◽  
pp. 823-840 ◽  
Author(s):  
R. A. McHardy ◽  
B. McK. Bary
Keyword(s):  
British Columbia ◽  
Dissolved Oxygen ◽  
Water Column ◽  
Oxygen Concentration ◽  
Seasonal Changes ◽  
Temperature Limit ◽  
Time Of Day ◽  
C Elegans ◽  
Vertical Distributions ◽  
Subsurface Light

Diurnal and seasonal changes in the distributions of two planktonic ostracods, Conchoecia elegans Sars and C. alata minor McHardy, have been considered in relation to changes in the temperature, salinity, oxygen concentration, and subsurface light in Indian Arm, British Columbia. Both species occurred frequently throughout the water column except near the surface. There is the suggestion (reinforced by data from other B.C. inlets) of an upper temperature limit for C. alata minor, which is lower than for C. elegans. Salinity and dissolved oxygen environments appear to have been similar for the two species. An upinlet displacement of both species-populations which took place in the early months of the year could possibly have been initiated by water which had intruded into the depths of Indian Arm. The vertical distributions of the two species showed statistically significant changes which varied with time of day, season, and geographic position. It was not possible to show that the depth of daylight distribution was strongly related to the penetration of light.

Studies of the hydrobiology of a tropical lake in north-western Queensland. II. Seasonal changes in thermal and dissolved oxygen characteristics

1980 ◽  
Vol 31 (5) ◽  
pp. 589 ◽  
Author(s):  
CM Finlayson ◽  
TP Farrell ◽  
DJ Griffiths
Keyword(s):  
Dissolved Oxygen ◽  
Water Column ◽  
Environmental Conditions ◽  
Seasonal Changes ◽  
Thermal Stratification ◽  
Oxygen Depletion ◽  
Tropical Lake ◽  
North Western

The stratification characteristics of Lake Moondarra (24�34'S.,139�35'E.), a man-made lake in north- western Queensland, have been studied. Evidence is presented that the lake approximates the warm polymictic type in which no persistent thermal stratification ever develops. During the cooler months, thermal stratification breaks down during the night; in the warmer months, the intense rainstorms prevent the establishment of a persistently stratified water column. The shallowness of the lake relative to its surface areaand the prevailing environmental conditions ensure that extensive periods of oxygen depletion do not develop in the water column. It is concluded that a strong and prolonged period of thermal stratification, with subsequent serious effects of the availability of dissolved oxygen in the deeper layers, would only arise if, in a particular year. there were no significant rainstorms.

scholarly journals ALTERACIONES FISICO-QUIMICAS DE LA COLUMNA DE AGUA, GENERADAS POR EL USO DEL BOLICHE (METODO DE PESCA ARTESANAL) EN LA CIENAGA GRANDE DE SANTA MARTA, CARIBE COLOMBIANO

2016 ◽  
Vol 24 ◽  
Author(s):  
Mario Enrique Rueda ◽  
José Ernesto Mancera P.
Keyword(s):  
Dissolved Oxygen ◽  
Water Column ◽  
Oxygen Concentration ◽  
Coastal Lagoon ◽  
Water Transparency ◽  
Dissolved Oxygen Concentration ◽  
Artisanal Fishing ◽  
Physical Chemical ◽  
Before And After ◽  
The Impact

With the purpose of assessing the impact generated by the use of an artisanal fishing method populary called "boliche", in the tropical coastal lagoon Ciénaga Grande de Santa Marta, different aspects were quantified; being one of them designed to analyze some physical-chemical alterations of the water column, produced during the fishing operations. The dissolved oxygen concentration, water transparency and seston composition and concentration, before and after of 70 boliche's thrusts were determinated. The results showthat fishing operations generate some momentary changes of little repercution to the ecosystem, such as particle resuspention principally inorganic an increase in seston concentration and a consequen water column transparency decrease. The dissolved oxygen concentration does not show appreciable alteration.

Influence of oxygen concentration on the distribution of Mysis relicta Lovén in a eutrophic temperate lake

1987 ◽  
Vol 65 (11) ◽  
pp. 2646-2650 ◽  
Author(s):  
R. K. Sherman ◽  
D. C. Lasenby ◽  
L. Hollett
Keyword(s):  
Dissolved Oxygen ◽  
Water Column ◽  
Oxygen Concentration ◽  
Eutrophic Lake ◽  
Oxygen Depletion ◽  
Mysis Relicta ◽  
Depth Limit ◽  
Southern Ontario ◽  
Lower Depth ◽  
Stagnation Period

The lower depth limit of a Mysis population in Crystal Lake, southern Ontario, gradually moved upward through the summer stagnation period, generally following a position just above the 1.0 mg/L dissolved oxygen isopleth. Mysis held in bioassay chambers demonstrated a 16-h LC50 value of 1.0 mg dissolved oxygen/L. Avoidance chamber experiments revealed that Mysis could detect and move away from areas of low dissolved oxygen concentrations. It is suggested that Mysis, which has been used as an indicator of oligotrophic conditions, could survive in a mesotrophic or eutrophic lake that undergoes oxygen depletion in the hypolimnion by moving upward in the water column.

Effect of Physicochemical Variables on Algal Autoflotation

1992 ◽  
Vol 26 (7-8) ◽  
pp. 1769-1778 ◽  
Author(s):  
S.-I. Lee ◽  
B. Koopman ◽  
E. P. Lincoln
Keyword(s):  
Dissolved Oxygen ◽  
Oxygen Concentration ◽  
Retention Time ◽  
Contact Time ◽  
Pilot Scale ◽  
Dissolved Oxygen Concentration ◽  
Physicochemical Variables ◽  
Rise Rate ◽  
Mixing Intensity ◽  
Maximum Rise

Combined chemical flocculation and autoflotation were examined using pilot scale process with chitosan and alum as flocculants. Positive correlation was observed between dissolved oxygen concentration and rise rate. Rise rate depended entirely on the autoflotation parameters: mixing intensity, retention time, and flocculant contact time. Also, rise rate was influenced by the type of flocculant used. The maximum rise rate with alum was observed to be 70 m/h, whereas that with chitosan was approximately 420 m/h. The efficiency of the flocculation-autoflotation process was superior to that of the flocculation-sedimentation process.

scholarly journals Gas–liquid mass transfer characteristics of aviation fuel scrubbing in an aircraft fuel tank

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Li Chaoyue ◽  
Feng Shiyu ◽  
Xu Lei ◽  
Peng Xiaotian ◽  
Yan Yan
Keyword(s):  
Mass Transfer ◽  
Dissolved Oxygen ◽  
Transfer Coefficient ◽  
Mass Transfer Coefficient ◽  
Oxygen Concentration ◽  
Gas Holdup ◽  
Aviation Fuel ◽  
Volumetric Mass Transfer Coefficient ◽  
Dissolved Oxygen Concentration ◽  
Liquid Mass Transfer

AbstractDissolved oxygen evolving from aviation fuel leads to an increase in the oxygen concentration in an inert aircraft fuel tank ullage that may increase the flammability of the tank. Aviation fuel scrubbing with nitrogen-enriched air (NEA) can largely reduce the amount of dissolved oxygen and counteract the adverse effect of oxygen evolution. The gas–liquid mass transfer characteristics of aviation fuel scrubbing are investigated using the computational fluid dynamics method, which is verified experimentally. The effects of the NEA bubble diameter, NEA superficial velocity and fuel load on oxygen transfer between NEA and aviation fuel are discussed. Findings from this work indicate that the descent rate of the average dissolved oxygen concentration, gas holdup distribution and volumetric mass transfer coefficient increase with increasing NEA superficial velocity but decrease with increasing bubble diameter and fuel load. When the bubble diameter varies from 1 to 4 mm, the maximum change of descent rate of dissolved oxygen concentration is 18.46%, the gas holdup is 8.73%, the oxygen volumetric mass transfer coefficient is 81.45%. When the NEA superficial velocities varies from 0.04 to 0.10 m/s, the maximum change of descent rate of dissolved oxygen concentration is 146.77%, the gas holdup is 77.14%, the oxygen volumetric mass transfer coefficient is 175.38%. When the fuel load varies from 35 to 80%, the maximum change of descent rate of dissolved oxygen concentration is 21.15%, the gas holdup is 49.54%, the oxygen volumetric mass transfer coefficient is 44.57%. These results provide a better understanding of the gas and liquid mass transfer characteristics of aviation fuel scrubbing in aircraft fuel tanks and can promote the optimal design of fuel scrubbing inerting systems.

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