The Organic Metabolism of Sea-water with Special Reference to the Ultimate Food Cycle in the Sea

Author(s):  
Ancel Keys ◽  
E. H. Christensen ◽  
August Krogh

Studies are reported of the behaviour of stored sea-water with regard to oxygen, ammonia, and bacteria content in relation to the conditions of storage and to the effect of various filtration procedures.When sea-water is sterilised by filtration and stored in the dark, the oxygen content remains constant or diminishes only by less than 0·07c.c. per litre in several hundred hours.In non-sterile experiments there is always an oxygen consumption roughly parallel to a bacterial multiplication which begins very suddenly after collection of the water. These effects are greatest in “raw” water, less in paper-filtered water and least in water which is doubly filtered.

1959 ◽  
Vol 196 (3) ◽  
pp. 633-641 ◽  
Author(s):  
A. V. Wolf ◽  
Phoebe G. Prentiss ◽  
Lillian G. Douglas ◽  
Russell J. Swett

Under certain conditions in which food provides an adequate caloric intake but too little water to sustain a cat or a rat in euhydration, these animals can be shown to depend for survival on their intake of sea water. They will generally drink enough sea water ad libitum to thrive, even overcoming thereby a previously induced water deficit; or, they will readily eat their food, mixed with sea water in amounts which can vary widely, with similar benefit. Without sea water they undergo progressive hydropenia and die. Along with experimental verification of the potability of sea water a theory of sea water drinking (mariposia) is presented, based upon the concept of urinary osmotic space.


1939 ◽  
Vol 16 (3) ◽  
pp. 363-373 ◽  
Author(s):  
C. A. WINGFIELD

1. The oxygen consumption of normal and gill-less nymphs of the mayflies Baetis sp., Cloeon dipterum and Ephemera vulgata has been measured at various oxygen concentrations. 2. It has been found that over the complete range of oxygen concentrations studied, the tracheal gills do not aid oxygen consumption in Baetis sp. In Cloeon dipterum, at all oxygen concentrations tested, no gaseous exchange takes place through the gills; at low oxygen concentrations, however, the gills function as an accessory respiratory mechanism in ventilating the respiratory surface of the body and so aid oxygen consumption. In Ephemera Vulgata the gills aid oxygen consumption even at high oxygen concentrations. In this species the gills may function both as true respiratory organs and as a ventilating mechanism. 3. It is shown that the differences in gill function can be related to the oxygen content of the habitat of each species.


Author(s):  
Yopi Novita ◽  
Budhi Hascaryo Iskandar ◽  
Bambang Murdiyanto ◽  
Budy Wiryawan ◽  
Hariyanto Hariyanto

Disolved oxygen plays an important role for fish living in its life environment. Information on the ammount of oxygen consumption of a fish in certain volume of water is needed in order to give balancing between the ammount of disolved oxygen and fish in it. The objective of this research is obtaining oxygen consumption level of a juvenile of humpback grouper (Cromileptes altivelis) of 5-7 cm body length. Oxygen consumption of fish was measured using a tube that equiped with DO tool (dissolved oxygent, DO), and the tube was filled by sea water. Measurement of oxygen con-sumption of juvenil was done by measuring the concentration of dissolved oxygen from sea water in the respirometer tube, began when fish had entered into the respirometer tube up to two hours observation. The result showed that oxygen consumption rate of a juvenile of humpback grouper (Cromileptes altivelis) of 5-7 cm length, is ranging between 0.816 and 1.734 mg/hour.


Energy generation to the present growing population is a crucial challenge for the power sector. Heat exchangers (HE) plays an important role in the industrial development. In this present work an attempt is made to develop a Shell-and- Tube Heat Exchanger (STHE) with segmental baffles using commercial CATIA V5 and Autodesk CFD Simulation Softwares. TEMA standards are considered for design of STHE with baffle-cut of 25%. 3-different sets of fluids are allowed to pass through the shell and tube sides i.e. Methanol - Sea Water (M-S), Distilled Water – Raw Water (D-R) and Kerosene- Crude Oil (K-C). The boundary conditions imposed for analysis are fluid inlet temperatures and velocities. ϵ-NTU is employed for the validation of simulation results and found good agreement between them. Results are plotted for temperature, pressure and velocity contours. The performance of the STHE is shown best for the K-C fluid set among other fluid sets.


1982 ◽  
Vol 101 (1) ◽  
pp. 135-141 ◽  
Author(s):  
H.A. EDWARDS

1. Oxygen consumption of A. aegypti larvae, about 210 mul l g−1 tissue wet weight h−1, does not change when the salinity of the environment is changed. The number of mitochondria in the anal papillae, a salt-absorbing epithelium, increases as the external medium is diluted. There is no difference in oxygen consumption between isolated anal papillae in 0, 2 and 20% sea water. The papillae represent about 5% of body volume and their oxygen consumption is about 2% of the animal's total. The theoretical minimum energy cost of osmoregulation is four orders of magnitude smaller than the measured figure for the anal papillae alone. Osmoregulatory phenomena which would explain the recorded observations are discussed.


1983 ◽  
Vol 104 (1) ◽  
pp. 193-201 ◽  
Author(s):  
B. Grubb ◽  
D. D. Jorgensen ◽  
M. Conner

Cardiovascular variables were studied as a function of oxygen consumption in the emu, a large, flightless ratite bird well suited to treadmill exercise. At the highest level of exercise, the birds' rate of oxygen consumption (VO2) was approximately 11.4 times the resting level (4.2 ml kg-1 min-1). Cardiac output was linearly related to VO2, increasing 9.5 ml for each 1 ml increase in oxygen consumption. The increase in cardiac output is similar to that in other birds, but appears to be larger than in mammals. The venous oxygen content dropped during exercise, thus increasing the arteriovenous oxygen content difference. At the highest levels of exercise, heart rate showed a 3.9-fold increase over the resting rate (45.8 beats min-1). The mean resting specific stroke volume was 1.5 ml per kg body mass, which is larger than shown by most mammals. However, birds have larger hearts relative to body mass than do mammals, and stroke volume expressed per gram of heart (0.18 ml g-1) is similar to that for mammals. Stroke volume showed a 1.8-fold increase as a result of exercise in the emus, but a change in heart rate plays a greater role in increasing cardiac output during exercise.


2019 ◽  
Author(s):  
Arpan Mehta ◽  
Adrian Pichurko

Preoxygenation allows a margin of safety prior to establishing control of a patient’s airway. Effective preoxygenation is influenced by careful technique, respiratory physiology, blood oxygen content, and total body oxygen consumption. Total body oxygen consumption is increased in the pregnant, pediatric, and obese populations, making maintenance of oxygenation more difficult during apnea. In addition to a standard facemask, advanced equipment such as high-flow nasal cannula, THRIVE, and various mask variants may be used. Positioning of a patient for advanced airway management affects preoxygenation, respiratory mechanics, and the conditions for establishing a definitive airway. The “triple airway support” maneuver consists of head extension, neck flexion, and protrusion of the mandibular teeth over the upper teeth; and provides effective mechanics for positive-pressure mask ventilation. Patients with potentially unstable cervical spines present additional challenges and, especially in emergency situations, require careful negotiation of priorities. Common maneuvers such as head tilt, jaw thrust, cricoid pressure, and manual in-line stabilization can cause motion in the unstable cervical spine with uncertain effects.  This review contains 7 figures, 5 tables, and 43 references. Keywords: preoxygenation, functional residual capacity, blood oxygen content, alveolar fraction of oxygen, total body oxygen consumption, high-flow nasal cannula, apneic oxygenation, sniffing position, triple airway support maneuver, manual in-line stabilization


1960 ◽  
Vol 199 (1) ◽  
pp. 179-182 ◽  
Author(s):  
Abraham Guz ◽  
George S. Kurland ◽  
A. Stone Freedberg

Coronary flow, heart rate, myocardial oxygen consumption and Walton strain gauge tension were determined in the isolated rabbit heart perfused with hemoglobin solutions of varying oxygen content. Perfusion was carried out under constant pressure and with the hemoglobin solution in equilibrium with 3% CO2 and 97% air under atmospheric tension. Oxygen content was varied from 2 to 18 vol. % by diluting hemoglobin with Ringer-Locke solution. Change from a higher to lower oxyhemoglobin concentration resulted in increased coronary flow; the reserve led to decreased flow. Heart rate, myocardial tension and oxygen consumption were constant at oxygen capacity above 2 vol. %.


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