A Method for Predicting Winter Oxygen Profiles in Ice-covered Ontario Lakes

1982 ◽  
Vol 39 (9) ◽  
pp. 1267-1272 ◽  
Author(s):  
Michael B. Jackson ◽  
David C. Lasenby
Keyword(s):  
Oxygen Concentration ◽  
Loss Rate ◽  
Ice Cover ◽  
Maximum Volume ◽  
Simple Method ◽  
Oxygen Loss ◽  
Oxidation Processes ◽  
Oxygen Profile ◽  
Shield Lakes ◽  
Oxygen Profiles

A simple method is presented for predicting oxygen profiles under ice cover in selected Ontario lakes. The oxygen loss rate within individual lake strata over winter can be predicted from the oxygen concentration in each stratum about 5 – 15 d after freeze-up (at the time of maximum volume-weighted oxygen concentration for the lake). Shield lakes and limestone-transition lakes are described by two distinct relationships; the rate of oxygen loss per unit oxygen concentration is greater in the limestone-transition lakes.Key words: lake-oxygen concentration, limestone lakes, lake respiration, oxygen profile, lake depth, oxygenation/oxidation processes, ice cover, Shield lakes

A lack of aerenchyma and high rates of radial oxygen loss from the root base contribute to the waterlogging intolerance of Brassica napus

1999 ◽  
Vol 26 (1) ◽  
pp. 87 ◽  
Author(s):  
L.A.C.J. Voesenek ◽  
W. Armstrong ◽  
G.M. Bögemann ◽  
T.D. Colmer ◽  
M.P. McDonald
Keyword(s):  
Brassica Napus ◽  
Lateral Roots ◽  
Biomass Accumulation ◽  
Radial Oxygen Loss ◽  
Low Oxygen ◽  
Root Porosity ◽  
Oxygen Loss ◽  
Basal Portion ◽  
Pre Treatment ◽  
Oxygen Profiles

The morphology and physiology of the response of two cultivars of Brassica napus to an anaerobic root medium was investigated. The cultivars Chikuzen and Topas showed a large reduction in growth rate when their roots were exposed to a de-oxygenated stagnant nutrient solution containing 0.1% w/v agar. Older seedlings (11 d old) were more sensitive to stagnant agar, expressed as biomass accumulation, than younger ones (5 d old). Brassica napus was characterized by a constitutively low root porosity (3–5%), typical for plant species with a low tolerance to waterlogging. A hypoxia pre- treatment (16 h; 2.25% O2) before exposure to de-oxygenated stagnant agar had no effect on the final number or length of lateral roots and adventitious roots. Brassica napus cv. Chikuzen is characterized by radial oxygen loss being most at the basal portion of the root, when a strong oxygen sink surrounds the root. Oxygen profiles through laterals of Brassica napus cv. Chikuzen show a typical pattern with low oxygen concentrations in the stele and somewhat higher levels in the cortex. Despite the continuum of intercellular air spaces in the root cortical tissue the lack of aerenchyma and therefore low rates of internal oxygen diffusion restricts root growth in anaerobic media and presumably contributes to the sensitivity of Brassica napus to waterlogging.

scholarly journals The role of atomic oxygen concentration in the ionization balance of the lower ionosphere during solar proton events

2008 ◽  
Vol 26 (1) ◽  
pp. 131-143 ◽  
Author(s):  
A. Osepian ◽  
V. Tereschenko ◽  
P. Dalin ◽  
S. Kirkwood
Keyword(s):  
Electron Density ◽  
Oxygen Concentration ◽  
Atomic Oxygen ◽  
Negative Ions ◽  
Solar Proton ◽  
Negative Ion ◽  
Proton Event ◽  
Density Profiles ◽  
Oxygen Profile ◽  
Atomic Oxygen Concentration

Abstract. The influence of atomic oxygen concentration on the height distribution of the main positive and negative ions and on electron density in the mesosphere is studied for the conditions prevailing during the solar proton event on 17 January 2005. It is shown by numerical modeling that the electron and ion density profiles are strongly dependent on the choice of the atomic oxygen profile. Experimental measurements of the electron density are used as the criterion for choosing the atomic oxygen profile in the mesosphere. With the help of modeling, the atomic oxygen profile in the daytime in the winter mesosphere is found to lead to a model electron density profile best matching the electron density profile obtained experimentally. As a result, with the help of modeling, we find the atomic oxygen profiles at various solar zenith angles in the winter mesosphere which lead to model electron density profiles matching the electron density profiles obtained experimentally. Alteration of the atomic oxygen concentration leads to a redistribution of the abundance of both positive and negative ion constituents, with changes in their total concentrations and transition heights. In consequence this results in changes of the electron density and effective recombination coefficient. For conditions of low concentration of atomic oxygen (during a solar proton event), the formation of cluster ions is the key process determining electron and ion densities at altitudes up to 77 km. The complex negative CO3− ion is formed up to about 74 km and the final NO3− ion, which is stable in relation to the atomic oxygen, is the dominant negative ion up to 74 km. As a result the transition heights between cluster ions and molecular ions and between negative ions and electron density are located at 77 km and 66 km, respectively.

A Simple Method by Which to Obtain a Desired Oxygen Concentration

1987 ◽  
Vol 66 (5) ◽  
pp. 717-717
Author(s):  
KEVIN W. ROBERTS ◽  
BERNARD C. DELEO
Keyword(s):  
Oxygen Concentration ◽  
Simple Method

scholarly journals Analysis on Variation of Oxygen Loss Rate in AIP System

2021 ◽  
Vol 2029 (1) ◽  
pp. 012154
Author(s):  
Feng Shi ◽  
Fan Zeng ◽  
Zuo Zhou
Keyword(s):  
Loss Rate ◽  
Oxygen Loss

scholarly journals Dissolved Oxygen Profiles and Its Problems at Lake Maninjau, West Sumatra – Indonesia

2021 ◽  
Vol 1 (1) ◽  
pp. 7-11
Author(s):  
Luki Subehi ◽  
Iwan Ridwansyah ◽  
Takehiko Fukushima
Keyword(s):  
Water Quality ◽  
Dissolved Oxygen ◽  
Tropical Lake ◽  
Small Rivers ◽  
Ecological Information ◽  
Cultured Fish ◽  
West Sumatra ◽  
Oxygen Profile ◽  
Fish Cages ◽  
Oxygen Profiles

In general, the tropical lake in Indonesia is one of the unique ecosystems which are functioning in both ecological and economic services. This study aims to analyze the dissolved oxygen profile of caldera tropical lake represented by Lake Maninjau at West Sumatera, Indonesia, and its impacts. Lake Maninjau is not only for culture fisheries but also serves as important hydroelectricity power. Surveys at Lake Maninjau were conducted in August 2006, March 2014, September 2017, and April 2018. The results showed that the average depth is 105 m. It covers 13,260 ha of an area with an elevation of 461.5 m above sea level and a maximum depth of 165 m. The lake water comes from rainfall, small rivers, and the surrounding groundwater, with one outflow in the Batang Antokan River. Based on the measurement, it was observed that decreasing dissolved oxygen levels occurred at the surface to the depth of 40 m in 2006, and changed from surface to a depth of 12 m in 2018 indicating the worse condition of water quality compared with the previous years.  Recently, bad water quality with mass mortality of cultured fish often occurs. Next, the percentage of fish cages area at Lake Maninjau in 2017 was 0.43%. Besides human activities, it was suggested that fish cages also contributed pollutant load to this lake. To maintain the sustainability of the lake, basic ecological information is necessary for the next study.

Oxygen dynamics and flow patterns of Dysidea avara (Porifera: Demospongiae)

2007 ◽  
Vol 87 (6) ◽  
pp. 1677-1682 ◽  
Author(s):  
Marie-Lise Schläppy ◽  
Friederike Hoffmann ◽  
Hans Røy ◽  
René H. Wijffels ◽  
Dominick Mendola ◽  
...  
Keyword(s):  
Oxygen Concentration ◽  
Particle Tracking ◽  
Particle Tracking Velocimetry ◽  
Flow Patterns ◽  
Sponge Tissue ◽  
Dysidea Avara ◽  
Aquarium Water ◽  
Pumping Rates ◽  
Oxygen Dynamics ◽  
Oxygen Profiles

The present publication presents oxygen properties and pumping behaviour of Dysidea avara. Oxygen profiles were measured near and inside the atrial space of the osculum with a Clark-type micro-electrode. Pumping sponges had profiles with oxygen concentrations marginally lower than that of the aquarium water. In contrast, diffusive profiles, with a clear boundary layer above the sponge surface, and oxygen penetrating only 0.5 mm into the sponge tissue, were typically that of a sponge which was not pumping. Diffusive oxygen flux at the sponge surface was 4.2 μmol O2 cm2 d1 and the calculated volumetric filtration rate was 0.3 cm3 water cm3 sponge min1. The oxygen concentration in the osculum was temporally fluctuating between 95 and 59% saturation at a frequency of approximately once per minute. The combination of static oxygen micro-electrode measurements and particle tracking velocimetry (PTV) allowed us to simultaneously observe fine-scale oxygen fluxes and oscular flow patterns in active sponges, even at extremely low pumping rates. Oscular oxygen concentration and flow were correlated but not always synchronous to the second. Particle tracking velocimetry was used to visualize the flow field around the sponge and to distinguish sponge-generated flow from the unidirectional current in a flow-cell.

Calibration Factor for Determination of Interstitial Oxygen Concentration in Germanium by Infrared Absorption

2005 ◽  
Vol 108-109 ◽  
pp. 735-740 ◽  
Author(s):  
Valentin V. Litvinov ◽  
Bengt Gunnar Svensson ◽  
L.I. Murin ◽  
J. Lennart Lindström ◽  
Vladimir P. Markevich
Keyword(s):  
Oxygen Concentration ◽  
Infrared Absorption ◽  
Secondary Ion Mass Spectrometry ◽  
Calibration Coefficient ◽  
Interstitial Oxygen ◽  
Oxygen Loss ◽  
Donor Formation ◽  
Kinetics Of ◽  
Secondary Ion

Intensities of infrared absorption due to asymmetric stretching vibrations of interstitial oxygen atoms in Ge crystals enriched with 16O and 18O isotopes have been compared with oxygen concentrations determined by means of secondary ion mass spectrometry (SIMS). For Ge samples with oxygen content less than 5⋅1017 cm-3 a good correlation has been found between the values of oxygen concentration and values of absorption coefficient in maximum of the absorption band at 855.6 cm-1 with a proportionality coefficient CO = 0.95.1017 сm-2. It is argued that kinetics of oxygen-related thermal double donor formation and oxygen loss upon heat-treatments of Ge crystals at 350 оС cannot be described properly with the application of calibration coefficient CO = 5.1016 cm-2, which is widely used for the determination of oxygen concentration in Ge crystals.

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