The temperature dependence of the solubility of oxygen in sea water according to the pulsed NMR data

Mel’nichenko, N. A.; Koltunov, A. M.; Vyskrebentsev, A. S.; Bazhanov, A. V.

doi:10.1134/s0036024408050105

Cited by 17 publications

(9 citation statements)

References 11 publications

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“…In the presence of oxygen ([O 2 ] 0 = 0.243 mM) and 1 mg L –1 SRFA, two independent estimates of the system pseudoequilibrium E h from both Cu 2+ /Cu + and O 2 /O 2 – couples may be deduced (as shown below), particularly as the concentration of Cu(I) attains a steady state of ∼0.13 μM (Figure C). The similarity in these two independent estimates of the system pseudoequilibrium E h should provide confidence in the model used to predict the concentration of O 2 – (and in the assumption that it is the E h of the O 2 /O 2 – couple rather than O 2 /H 2 O which is relevant to Cu(I) oxidation).…”

Section: Resultsmentioning

confidence: 99%

“…The kinetics of Cu(II) reduction will thus be retarded as the reaction proceeds for two major reasons: (i) the tendency for electron transfer would be expected to decrease (due to the increase in the E h of the dominant Q/Q − couple), and (ii) as the concentration of the more labile electron donor groups in SRFA decreases (or is exhausted), some potential electron donor groups will no longer be available due to the rise in the E h of the system. In the presence of oxygen ([O 2 ] 0 = 0.243 mM 65 ) and 1 mg L −1 SRFA, two independent estimates of the system pseudoequilibrium E h from both Cu 2+ /Cu + and O 2 /O 2 − couples may be deduced (as shown below), particularly as the concentration of Cu(I) attains a steady state of ∼0.13 μM (Figure 2C). The similarity in these two independent estimates of the system pseudoequilibrium E h should provide confidence in the model used to predict the concentration of O 2 − (and in the assumption that it is the E h of the O 2 /O 2 − couple rather than O 2 /H 2 O which is relevant to Cu(I) oxidation).…”

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Kinetics of Cu(II) Reduction by Natural Organic Matter

2012

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The kinetics of Cu(II) reduction by Suwannee River fulvic acid (SRFA) at concentrations from 0.25 to 8 mg L(-1) have been investigated in 2 mM NaHCO(3) and 0.7 M NaCl at pH 8.0. In the absence of oxygen, SRFA reduced Cu(II) to Cu(I) in a biphasic manner, with initial rapid formation of Cu(I) followed by a much slower increase in Cu(I) concentration over time. When present, oxygen only had a noticeable effect on Cu(I) concentrations in the second phase of the reduction process and at high [SRFA]. In both the absence and presence of oxygen, the rate of Cu(I) generation increased with increasing [SRFA]. At 8 mg L(-1) [SRFA], nearly 75% of the 0.4 μM Cu(II) initially present was reduced to Cu(I) after 20 min, although the yield of Cu(I) relative to [SRFA] decreased at [SRFA] > 1 mg L(-1). Two plausible kinetic modeling approaches were found to satisfactorily describe the experimental data over a range of [SRFA]. Despite some uncertainty as to which approach is correct, common features of both approaches were complexation of Cu(II) by SRFA and reduction of Cu(II) by two different electron donor groups within SRFA: a relatively labile electron donor (with a concentration of 1.1 × 10(-4) equiv of e(-) (g of SRFA)(-1)) that reduced Cu(II) relatively rapidly and a less labile donor (with a concentration of 3.1 × 10(-4) equiv of e(-) (g of SRFA)(-1)) that reduced Cu(II) more slowly.

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Section: Resultsmentioning

confidence: 99%

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Kinetics of Cu(II) Reduction by Natural Organic Matter

2012

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“…Hematocrit correlates robustly with thermal tolerance across species (Beers and Sidell, 2011). The loss of oxygen carrying capacity that results from reduced hemoglobin expression is viable in cold water environments because oxygen saturation in saltwater nears maximal levels as temperature approaches freezing (Mel’nichenko et al, 2008). Since hemoglobin (with bound iron) makes up 90% of the dry weight content of red blood cells (Rishi and Subramaniam, 2017), iron levels in an organism correlate with hematocrit.…”

Section: Discussionmentioning

confidence: 99%

Vascular Expression of Hemoglobin Alpha in Antarctic Icefish Supports Iron Limitation as Novel Evolutionary Driver

Corliss

DeLalio

et al. 2019

Front. Physiol.

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Frigid temperatures of the Southern Ocean are known to be an evolutionary driver in Antarctic fish. For example, many fish have reduced red blood cell (RBC) concentration to minimize vascular resistance. Via the oxygen-carrying protein hemoglobin, RBCs contain the vast majority of the body’s iron, which is known to be a limiting nutrient in marine ecosystems. Since lower RBC levels also lead to reduced iron requirements, we hypothesize that low iron availability was an additional evolutionary driver of Antarctic fish speciation. Antarctic Icefish of the family Channichthyidae are known to have an extreme alteration of iron metabolism due to loss of RBCs and two iron-binding proteins, hemoglobin and myoglobin. Loss of hemoglobin is considered a maladaptive trait allowed by relaxation of predator selection since extreme adaptations are required to compensate for the loss of oxygen-carrying capacity. However, iron dependency minimization may have driven hemoglobin loss instead of a random evolutionary event. Given the variety of functions that hemoglobin serves in the endothelium, we suspected the protein corresponding to the 3’ truncated Hbα fragment (Hbα-3’f) that was not genetically excluded by icefish may still be expressed as a protein. Using whole mount confocal microscopy, we show that Hbα-3’f is expressed in the vascular endothelium of icefish retina, suggesting this Hbα fragment may still serve an important role in the endothelium. These observations support a novel hypothesis that iron minimization could have influenced icefish speciation with the loss of the iron-binding portion of Hbα in Hbα-3’f, as well as hemoglobin β and myoglobin.

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“…5) are consistent with other findings of oxygen solubility as a function of temperature. 20,21 Because the increasing temperature only accelerates the chemical reaction rate in this closed system, the proposed method is efficient for detecting oxygen levels at high solution temperature. As shown in Fig.…”

Section: Effect Of the Sample Temperaturementioning

confidence: 99%

Development of a Photometric Method to Measure Molecular Oxygen in Water

et al. 2020

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A photometric method to determine molecular oxygen in water was developed. When manganese(II) is oxidized by oxygen under alkaline conditions, the presence of polyphosphate can prevent the precipitation due to a coacervate reaction. The oxidized manganese later dissolves in acid to form a pink Mn(III) species, which has a stable UV/vis spectrum. The monitoring of the oxygen concentration based on the absorbance of the pink Mn(III) species at 517 nm showed a strong correlation with both the Winkler method and an optical sensor. As a result, the present method can measure not only dissolved oxygen but also fine bubbles oxygen in in the water sample with high reliability (0-26 mg dm -3 , r 2 = 0.9995). During this process, no significant interference from nitrite or metal ions was observed. The accuracy of measurement was steady at high temperatures of the water samples (≤ 363 K).

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The temperature dependence of the solubility of oxygen in sea water according to the pulsed NMR data

Cited by 17 publications

References 11 publications

Kinetics of Cu(II) Reduction by Natural Organic Matter

Kinetics of Cu(II) Reduction by Natural Organic Matter

Vascular Expression of Hemoglobin Alpha in Antarctic Icefish Supports Iron Limitation as Novel Evolutionary Driver

Development of a Photometric Method to Measure Molecular Oxygen in Water

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