Simple Method of Measuring Seston Respiration in Oligotrophic Lakes

1986 ◽  
Vol 43 (8) ◽  
pp. 1660-1663 ◽  
Author(s):  
R. J. Cornett ◽  
F. H. Rigler
Keyword(s):  
Oxygen Consumption ◽  
Oxygen Concentration ◽  
Water Samples ◽  
Simple Technique ◽  
Oxygen Demand ◽  
Simple Method ◽  
Rate Of Oxygen Consumption ◽  
The Difference ◽  
Abiotic Influences ◽  
And Control

A simple technique for measuring the oxygen consumption of seston in oligotrophic waters was developed and tested. Water samples were filtered through 0.45-μm filters. The filters were suspended in biological oxygen demand bottles containing lake water. NaN3 added to one bottle stopped respiration and served as a control to eliminate abiotic influences during the experiments. The difference in oxygen concentration between the respiring and control samples increased linearly over the 1-d experiments. Filtration of hypolimnetic water samples did not significantly alter the rate of oxygen consumption of the seston. Concentrating the seston increased the change in oxygen concentration so that respiration rates from 2 to 80 mg O2∙m−3∙d−1 could be measured. This method is simple, precise, and can measure very low rates of respiration directly.

Burrowing behaviour and anaerobiosis in the bivalve Arctica islandica (L.)

1976 ◽  
Vol 56 (1) ◽  
pp. 95-109 ◽  
Author(s):  
A. C. Taylor
Keyword(s):  
Oxygen Consumption ◽  
Initial Rate ◽  
Recovery Period ◽  
Oxygen Demand ◽  
Ventilation Rate ◽  
Oxygen Utilization ◽  
Arctica Islandica ◽  
Aerobic Conditions ◽  
Rate Of Oxygen Consumption ◽  
Burrowing Activity

In laboratory tanks as well as in the sea Arctica islandica shows a pattern of intermittent burrowing activity. Periods spent at the surface of the deposit alternate with periods buried several centimetres beneath the surface of the sand, during which the animals respire anaerobically. There is no obvious rhythmicity to this behaviour; the duration of periods spent beneath the surface is very variable even in the same animal, but normally lasts between 1 and 7 days.On the return to aerobic conditions both the heart rate and oxygen consumption areincreased but decline gradually during the following 20–25 h. This increased oxygen uptake is caused primarily by an increase in oxygen utilization but there is little change in ventilation rate. Both the initial rate of oxygen consumption and the duration of the recovery period show a correlation with the duration of the period of anaerobiosis. The concentration of alaninc in the blood of Arctica is high immediately after the return to aerobic conditions but declines during the recovery period. The similarity in the time taken for the concentration of alanine in the blood and the oxygen consumption of Arctica to return to normal levels suggests that at least part of this increased oxygen demand is associated with the metabolism of end-products of anaerobiosis.

scholarly journals MODIFIED ATMOSPHERE PACKAGING: TEMPERATURE DEPENDENCE OF THE RQ “BREAKPOINT”

HortScience ◽  
1990 ◽  
Vol 25 (9) ◽  
pp. 1139c-1139
Author(s):  
Randolph Beaudry ◽  
Arthur Cameron
Keyword(s):  
Carbon Dioxide ◽  
Steady State ◽  
Temperature Dependence ◽  
Oxygen Concentration ◽  
Modified Atmosphere Packaging ◽  
Oxygen Demand ◽  
Carbon Dioxide Production ◽  
Modified Atmosphere ◽  
Lower Oxygen ◽  
The Difference

The steady-state oxygen concentration at which blueberry fruit began to exhibit anaerobic carbon dioxide production. (i.e., the RQ breakpoint) was determined for fruit held at 0, 5, 10, 15, 20 and 25 C using a modified atmosphere packaging (MAP) system. As fruit temperature decreased, the RQ breakpoint occurred at lower oxygen concentrations. The decrease in the RQ breakpoint oxygen is thought to be due to a decreasing oxygen demand of the cooler fruit.The decrease in oxygen demand and concomitant decrease in oxygen flux would have resulted in a decrease in the difference in the oxygen concentrate on between the inside and outside of the fruit and thus decreased the minimum amount of oxygen tolerated. The implications on MAP strategies will be discussed.

scholarly journals Lability of natural organic matter in freshwater: a simple method for detection using hydrogen peroxide as an indicator

2018 ◽  
Author(s):  
Isabela Carreira Constantino ◽  
Amanda Maria Tadini ◽  
Marcelo Freitas Lima ◽  
Lídia Maria de Almeida Plicas ◽  
Altair Benedito Moreira ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Organic Matter ◽  
Organic Carbon ◽  
Natural Organic Matter ◽  
Water Samples ◽  
Ultrapure Water ◽  
Model Compounds ◽  
Simple Method ◽  
The Difference ◽  
One Year

Abstract. Natural organic matter (NOM) is an important component for understanding the behavior of pollutants in the environment. A fraction of NOM is considered labile, fresh and less oxidized. In this work, a simple method was developed to distinguish between labile (LOM) and recalcitrant (ROM) organic matter in freshwater samples. Pyruvate, lignin and fulvic acid were chosen as model compounds of labile and recalcitrant NOM. The samples were submitted to kinetic monitoring experiments using hydrogen peroxide. Pyruvate was the best standard for the quantification of LOM (for concetrations up to 2.9 mg L−1). ROM was quantified by measuring the difference between total organic carbon (TOC) and LOM concentrations. Curves obtained with 0.5 to 5.0 mg L−1 TOC (pyruvate) in freshwater or ultrapure water samples did not indicate the existence of a matrix effect. This simple method was applied to water samples that were collected monthly for one year; the resulting LOM concentrations ranged from 0.47 to 2.1 mg L−1 and the ROM concentrations ranged from 0.08 to 3.5 mg L−1. Based on this results we concluded that hydrogen peroxide kinetics can be used as a simple method to quantify LOM and ROM concentrations in freshwater samples.

The Respiratory Physiology of the Marine Nematodes Enoplus Brevis (Bastian) and E. Communis (Bastian)

1973 ◽  
Vol 59 (1) ◽  
pp. 255-266
Author(s):  
H. J. ATKINSON
Keyword(s):  
Oxygen Consumption ◽  
Body Size ◽  
Oxygen Tension ◽  
Dry Weight ◽  
Respiratory Physiology ◽  
Rate Of Oxygen Consumption ◽  
Oxygen Tensions ◽  
The Difference ◽  
Relationship Of ◽  
The Relationship

1. The rate of oxygen consumption of individual males of Enoplus brevis and E. communis was measured at 15 °C and at each of four oxygen tensions, 135, 75, 35, and 12 Torr, after at least 12 h experience of these conditions. 2. It was clearly demonstrated that the level of oxygen consumption of both species was reduced by each lowering of the imposed oxygen tension. 3. In all cases the oxygen consumption of each species fell with increasing body size. On a unit dry-weight basis the oxygen consumption of E. brevis is greater than that of the larger E. communis, but after allowing for the difference of body size the two species have more or less similar oxygen uptakes at all oxygen tensions. 4. In E. brevis oxygen tension influenced the relationship of body size and metabolism, the slope relating oxygen consumption and body weight becomes steeper with decreasing oxygen tension. This effect was not shown by E. communis. 5. Some general factors influencing the availability of oxygen to nematodes are considered.

The Swimming Energetics of Trout

1971 ◽  
Vol 55 (2) ◽  
pp. 521-540 ◽  
Author(s):  
P. W. WEBB
Keyword(s):  
Oxygen Consumption ◽  
Swimming Speed ◽  
Swimming Performance ◽  
The Body ◽  
Control Group ◽  
Muscle System ◽  
Rate Of Oxygen Consumption ◽  
Wet Weight ◽  
Standard Rate ◽  
The Difference

1. The oxygen consumption of rainbow trout was measured at a variety of subfatigue swimming speeds, at a temperature of 15 %C. Five groups of fish were used, a control group and four groups with extra drag loads attached to the body. 2. The logarithm of oxygen consumption was linearly related to swimming speed in all five groups, the slope of the relationship increasing with the size of the extra drag load. The mean standard rate of oxygen consumption was 72.5 mg O2/kg wet weight/h. The active rate of oxygen consumption was highest for the control group (628 mg O2/kg/h) and fell with increasing size of the attached drag load. The active rate for the control group was high in comparison with other salmonid fish, and in comparison with the value expected for the fish. This was not a result of the extra drag loads in the other groups. No explanation for this high value can be found. 3. The critical swimming speed for a 60 min test period was 58.1 cm/sec (2.0 body lengths/sec) for the control group. The values for the critical swimming speeds were slightly higher than those measured for the same species in a previous paper (Webb, 1971). The difference between the two sets of critical swimming speeds is attributed to seasonal changes in swimming performance. 4. The aerobic efficiency was found to reach values of 14.5-15.5% based on the energy released by aerobic metabolism in comparison with the calculated required thrust. 5. The anaerobic contribution to the total energy budget in increasing-velocity tests is considered to be small, and can be neglected. 6. It is concluded that the efficiency of the muscle system in cruising will be approximately 17-20% over the upper 80% of the cruising-speed range, while the caudal propeller efficiency will increase from about 15-75 % over the same range. 7. Consideration of the efficiency values for the caudal propeller calculated here, and those predicted by Lighthill's (1969) model of fish propulsion, suggest that the efficiency of the propeller system will reach an optimum value at the maximum cruising speeds of most fish, and will remain close to this value at spring speeds.

Permeance to oxygen of detached Capsicum annuum fruit

2000 ◽  
Vol 40 (3) ◽  
pp. 457 ◽  
Author(s):  
J. Bower ◽  
B. D. Patterson ◽  
J. J. Jobling
Keyword(s):  
Oxygen Consumption ◽  
Gas Exchange ◽  
Capsicum Annuum ◽  
Oxygen Concentration ◽  
Concentration Gradient ◽  
Gas Diffusion ◽  
Major Barrier ◽  
Capsicum Annuum L ◽  
Rate Of Oxygen Consumption ◽  
Low Rate

The internal oxygen concentration and rate of oxygen consumption of detached capsicum fruits (Capsicum annuum L.) were monitored over several days. From this their overall permeance to oxygen was calculated. When wax was applied to the pedicel and its scar, permeance was reduced by 80–90%, indicating that most gas exchange occurred through this area. Readings from O2 sensors attached to the skins of the fruits were compared to those from O2 sensors inserted into the fruit cavity. These indicated that the cuticle was the major barrier to gas diffusion and that there was a concentration gradient through the capsicum flesh. Permeance of the cuticle was found to be about 0.64 x 10–4 mol O2/Pa.m2.s, while permeance to CO2 was 2–3 times higher. This suggests that the cuticle is composed of a coherent film. The low rate of gas diffusion through capsicum cuticle may allow recycling of respired CO2 by photosynthesis in the flesh before harvest.

scholarly journals THE RESPIRATION OF LUMINOUS BACTERIA AND THE EFFECT OF OXYGEN TENSION UPON OXYGEN CONSUMPTION

1929 ◽  
Vol 13 (1) ◽  
pp. 27-45 ◽  
Author(s):  
Charles S. Shoup
Keyword(s):  
Carbon Dioxide ◽  
Oxygen Consumption ◽  
Oxygen Concentration ◽  
Oxygen Tension ◽  
Small Cells ◽  
Pure Oxygen ◽  
Catalytic Surfaces ◽  
Rate Of Oxygen Consumption ◽  
Luminous Bacteria ◽  
Effect Of Oxygen

1. The respiration of luminous bacteria has been studied by colorimetric and manometric methods. 2. Limulus oxyhaemocyanin has been used as a colorimetric indicator of oxygen consumption and indicator dyes were used for colorimetric determination of carbon dioxide production. 3. The Thunberg-Winterstein microrespirometer has been used for the measurement of the rate of oxygen consumption by luminous bacteria at different partial pressures of oxygen. 4. The effect of oxygen concentration upon oxygen consumption has been followed from equilibrium with air to low pressures of oxygen. 5. Luminous bacteria consume oxygen and produce carbon dioxide independent of oxygen pressures from equilibrium with air (152 mm.) to approximately 22.80 mm. oxygen or 0.03 atmosphere. 6. Dimming of a suspension of luminous bacteria occurs when oxygen tension is lowered to approximately 2 mm. Hg (0.0026 atmosphere) and when the rate of respiration becomes diminished one-half. 7. Pure nitrogen stops respiratory activity and pure oxygen irreversibly inhibits oxygen consumption. 8. The curve for rate of oxygen consumption with oxygen concentration is similar to curves for adsorption of gasses at catalytic surfaces, and agrees with the Langmuir equation for the expression of the amount of gas adsorbed in unimolecular layer at catalytic surfaces with gas pressure. 9. A constant and maximum rate of oxygen consumption occurs in small cells when oxygen concentration becomes sufficient to entirely saturate the surface of the oxidative catalyst of the cell.

Cardiac effects of hypoxia in the neotenous tiger salamanderAmbystoma tigrinum

2002 ◽  
Vol 205 (12) ◽  
pp. 1725-1734 ◽  
Author(s):  
Tom McKean ◽  
Guolian Li ◽  
Kong Wei
Keyword(s):  
Cardiac Output ◽  
Oxygen Consumption ◽  
Oxygen Concentration ◽  
Mechanical Performance ◽  
Cardiac Mass ◽  
Differentially Expressed ◽  
Representational Difference Analysis ◽  
Ambystoma Tigrinum ◽  
Rate Of Oxygen Consumption ◽  
Aquatic Salamanders

SUMMARYThe aquatic form of the tiger salamander Ambystoma tigrinum lives in high-altitude ponds and is exposed to a hypoxic environment that may be either chronic or intermittent. In many animal species, exposure to hypoxia stimulates cardiac output and is followed by an increase in cardiac mass. The working hypothesis of the present study was that the hearts of these aquatic salamanders exposed to 10-14 days of 5 % oxygen in a laboratory setting would become larger and would differentially express proteins that would help confer tolerance to hypoxia. During exposure to hypoxia, cardiac output increased, as did hematocrit. Cardiac mass also increased, but mitotic figures were not detected in the cardiac myocytes of colchicine-injected animals. The mass increase was probably due to hypertrophy, although a very slow rate of hyperplasia cannot be ruled out. Representational difference analysis indicated that at least 14 mRNAs were expressed in hearts from the hypoxic animals that were not expressed in hearts from normoxic animals. The differentially expressed genes were cloned and sequenced and confirmed as coming from the ventricles of the hypoxic salamanders. Genes differentially expressed include mitochondrial genes and genes for elongation factor 2, a protein synthesis gene. The mechanical performance of buffer-perfused hearts isolated from normoxic and hypoxic animals did not differ. Acute responses to hypoxia were also measured. The rate of oxygen consumption of unanesthetized salamanders in metabolism chambers decreased when chamber oxygen concentration was reduced below 12 % oxygen. At a chamber oxygen concentration of 4-6 %, the rate of oxygen consumption of the salamanders was reduced to approximately one-third of the normoxic rate.

Metabolic expenditure of waleye (Stizostedion vitreum vitreum) as determined by rate of oxgen consumption

1981 ◽  
Vol 59 (6) ◽  
pp. 882-889 ◽  
Author(s):  
Martin J. Tarby
Keyword(s):  
Oxygen Consumption ◽  
Unit Weight ◽  
Stizostedion Vitreum ◽  
Regression Equations ◽  
Feeding Experiments ◽  
Standard Metabolism ◽  
Heat Increment ◽  
Rate Of Oxygen Consumption ◽  
The Difference ◽  
Metabolic Expenditure

Energy expended by walleye (Stizostedion vitreum vitreum) for metabolism was assessed by measuring oxygen consumption of different size fish in respirometers under various conditions of temperature, activity, and ration. Standard metabolism was estimated as rate of oxygen consumption of unfed resting fish, and relationships to weight and temperature were expressed by simple and multiple regression equations. Although slopes for simple regressions did not differ significantly from slopes for analogous equations determined previously for walleye in maintenance feeding trials, the intercept or level of metabolism for a fish of unit weight at 20 °C computed from feeding experiments was over three times greater than that computed by respirometry. Heat increment, which was quantified from the difference in oxygen consumption of resting walleye fed and deprived of food at 20 °C, ranged from about 9 to 11% of the energy ingested and appeared independent of ration and fish size. Metabolism for swimming determined as the difference between rate of oxygen consumption of unfed fish resting and swimming one body length per second was calculated to be approximately equal to the energy expended by walleye for standard metabolism.

The influence of loss of plumage on temperature regulation in laying hens

1977 ◽  
Vol 89 (2) ◽  
pp. 393-398 ◽  
Author(s):  
S. A. Richards
Keyword(s):  
Ambient Temperature ◽  
Laying Hens ◽  
Core Body Temperature ◽  
Acclimation Temperature ◽  
Evaporative Heat Loss ◽  
Rate Of Increase ◽  
Rate Of Oxygen Consumption ◽  
The Difference ◽  
And Control ◽  
Core Body

summaryThe acute thermoregulatory responses of normally feathered (control) and poorly feathered laying hens were studied in the ambient temperature range from 0 to 38 °C.Core body temperature in the poorly feathered birds began to fall at between 15 and 20 °C but this difference from the controls was significant only at 0 and 5 °C, when there was severe hypothermia. The temperature on the skin of the back was significantly lower at 20 °C and below, but the comb temperatures did not differ.The rate of oxygen consumption in the poorly feathered hens was significantly higher than that of the controls at 30 CC and below; at the acclimation temperature (20–25 °C) the difference was about 62%. The rate of increase of heat production with falling ambient temperature was 2–6 W/ma/°C in the poorly feathered group and 1–0 W/ma/°C in the controls.Absolute rates of evaporative heat loss did not differ between the two groups.The ratio of the coefficients of dry heat transfer in the poorly feathered and control birds at 0–30 °C was 2–1:1.

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