scholarly journals Repeated measurement of Mo2 in small aquatic organisms: a manual intermittent flow respirometer using off-the-shelf components

2018 ◽  
Vol 124 (3) ◽  
pp. 741-749
Author(s):  
Daniel W. Baker ◽  
Michael E. Hudson ◽  
Emily J. Frost ◽  
Mary A. Sewell
Keyword(s):  
Environmental Conditions ◽  
Oxygen Sensor ◽  
Aquatic Organisms ◽  
Repeated Measurement ◽  
Respiratory Physiology ◽  
Intermittent Flow ◽  
Static Mode ◽  
The Face ◽  
Flow Through ◽  
Acute And Chronic Exposure

Measurement of rates of oxygen consumption ( Mo2) in small aquatic embryos or larvae (<1 mm) in response to altered environmental conditions has traditionally been challenging. Here, using modifications of a commercially available fluorescent optode flow-through cell (FTC; PreSens FTC-PSt3) and routine laboratory supplies (syringes, stopcocks, tubing), we have constructed a manual intermittent flow respirometer (MIFR) that allows measurement of Mo2 in small numbers of individuals when sequentially exposed to different environmental conditions (e.g., changes in seawater pH) through a gravity-driven media replacement perfusion system. We first show that the FTC can be used in “static” mode while incubating small numbers of embryos/larvae contained within the planar oxygen sensor (POS) chamber with Nitex filters. We then demonstrate the use of the MIFR by exposing larval echinoderms ( Fellaster zelandiae, Evechinus chloroticus, and Centrostephanus rodgersii) to seawater equilibrated with elevated CO2 and measured Mo2 during acute and chronic exposure to hypercapnia. This MIFR method will allow investigators to address questions regarding the respiratory physiology of small aquatic animals, such as the thresholds for metabolic depression in embryonic and larval forms. NEW & NOTEWORTHY A manual intermittent flow respirometer (MIFR), allowing media exchange in a flow-through cell containing small aquatic organisms, permits repeated measurement of Mo2 of individuals not only in a single medium (e.g., technical replication), but also in different media (here, high CO2-equilibrated seawater), enabling measurement of acute physiological responses to changed conditions. This versatile technique has wide-ranging implications for the study of the Mo2 response of aquatic organisms in the face of climate change.

Studies on the storage of potatoes. III. The composition of the atmosphere in a potato clamp

1950 ◽  
Vol 40 (3) ◽  
pp. 227-232 ◽  
Author(s):  
E. M. Crook ◽  
D. J. Watson
Keyword(s):  
Multiple Regression ◽  
Wind Velocity ◽  
Practical Importance ◽  
Oxygen Depletion ◽  
Unsaturated Compounds ◽  
The Face ◽  
Flow Through ◽  
The Mean ◽  
Oxygen Concentrations

The CO2 concentration in the atmosphere of a potato clamp varied between 0·06 and 0·86%. The sum of CO2 and oxygen concentrations remained approximately constant at 21%. The CO2 concentration increased with time from December to April. This was attributed to increase in the rate of respiration of the potatoes caused by rise of temperature. Wind blowing in the direction normal to the face of the clamp reduced the COa concentration, presumably by causing external air to flow through the clamp coverings. A multiple regression of CO2 concentration on temperature of the potatoes at the time of sampling, and on the mean component of wind velocity normal to the clamp face estimated over a period of 3 hr. before the time of sampling, accounted for 64% of the variance between sampling occasions.Unsaturated compounds were detected in the clamp atmosphere by absorption in bromine; the concentration of these, expressed as ethylene, varied between 0·004 and 0·025%.The magnitude of CO2 accumulation and oxygen depletion in the clamp atmosphere was too small to produce effects of practical importance on the storage behaviour of the potatoes. If the unsaturated compounds were ethylene, the concentration present was sufficient to cause appreciable retardation of sprouting.

Toxicity of pentachlorophenol to aquatic organisms under naturally varying and controlled environmental conditions

1986 ◽  
Vol 5 (6) ◽  
pp. 531-542 ◽  
Author(s):  
Steven F. Hedtke ◽  
Corlis W. West ◽  
Kathleen N. Allen ◽  
Teresa J. Norberg-King ◽  
Donald I. Mount
Keyword(s):  
Environmental Conditions ◽  
Aquatic Organisms

scholarly journals An electronic valve controller for current control during the recording of oxygen consumption in aquatic animals

1989 ◽  
Vol 8 (2) ◽  
pp. 74-76
Author(s):  
H. H. Du Preez ◽  
E. Grobler ◽  
J. M. Bell
Keyword(s):  
Oxygen Consumption ◽  
Control System ◽  
Oxygen Sensor ◽  
Aquatic Organisms ◽  
Current Control ◽  
Automatic Recording ◽  
Aquatic Animals ◽  
Power Circuit ◽  
Minute Period

A control system is described which allows the automatic recording of the oxygen consumption of five aquatic organisms and one control. The electronic valve controller operates six three-way valves which permit water from each of the six respiration chambers to flow successively past the oxygen sensor. A 38.4 kHz quartz cristal oscillator ensures a ten minute period and is not affected by disturbances on the power circuit.

Enabling Knowledge Flow

2021 ◽  
pp. 157-175
Author(s):  
Dana Tessier
Keyword(s):  
Knowledge Management ◽  
Corporate Culture ◽  
New Technology ◽  
Management Strategies ◽  
Management Model ◽  
New Knowledge ◽  
The Face ◽  
Flow Through ◽  
Management Behaviors

Organizations are facing many challenges to remain relevant in the face of new technology, emerging markets, and changing consumer behaviors. Many organizations look to become learning organizations with knowledge management strategies to leverage their knowledge assets and continuously innovate their strategies and products. However, organizations struggle to achieve success with knowledge management because their organizational culture does not support knowledge-sharing and must be adapted for this new behavior. Knowledge must flow through the organization, and so, therefore, these necessary behaviors must work within the existing corporate culture. Observations from a case study at a software company are discussed, and a new knowledge management model, the Knowledge Management Triangle, is introduced. The Knowledge Management Triangle is a simple model to explain and implement knowledge management within organizations and is customizable to work within the organization's culture to ensure the new knowledge management behaviors are appropriately adopted.

scholarly journals Morphometric differences of Spirlin, Alburnoides Bipunctatus Bloch 1782 from the Major Catchements of Transylvania

2017 ◽  
Vol 74 (2) ◽  
pp. 177 ◽  
Author(s):  
Tudor PĂPUC ◽  
Daniel COCAN ◽  
Călin LAŢIU ◽  
Paul UIUIU ◽  
Vioara MIREȘAN
Keyword(s):  
Veterinary Medicine ◽  
Environmental Conditions ◽  
Body Shape ◽  
Aquatic Organisms ◽  
Morphometric Characteristics ◽  
Morphometric Measurements ◽  
Agricultural Sciences ◽  
Different Populations ◽  
The University

Spirlin (Alburnoides bipunctatus) is found in great numbers in most Transylvanian rivers. The species has an important role in the ecosystems in which it is found in terms of feeding and habitat occupation. The morphmetric characthers of this species vary between different habitats, outlining morphometric plasticity. Morphometric profiles were made for different populations of Spirlin, to evaluate differences in body shape. Considering that different environmental conditions influence the morphology of Spirlin populations, morphometric characteristics were determined. In order to assess differences in spirlin body shape, specimens from the four major Transylvanian catchments were collected by angling techniques. The specimens were preserved and transported to the University of Agricultural Sciences and Veterinary Medicine, Cluj-Napoca, where morphometric measurements and weight determinations were conducted in the Physiology of Aquatic Organisms Laboratory. Spirlin from Mures, Somes, Cris and Viseu catchments were studied, as it follows: 21 specimens from Aries River (Mures catchment), 61 specimens from the river Crisul Repede (Cris catchment), 21 specimens from Somesul Mic River (Somes catchment) and 20 specimens from Viseu River. A number of 39 determinations were made. The obtained results reflect the morphometric differences among populations of Spirlin from some Transylvanian main rivers.

scholarly journals Comparative physiology of the pulmonary blood-gas barrier: the unique avian solution

2009 ◽  
Vol 297 (6) ◽  
pp. R1625-R1634 ◽  
Author(s):  
John B. West
Keyword(s):  
Gas Exchange ◽  
Complete Separation ◽  
External Support ◽  
Blood Gas ◽  
Large Area ◽  
Gas Barrier ◽  
Type Iv ◽  
Pulmonary Capillaries ◽  
The Face ◽  
Flow Through

Two opposing selective pressures have shaped the evolution of the structure of the blood-gas barrier in air breathing vertebrates. The first pressure, which has been recognized for 100 years, is to facilitate diffusive gas exchange. This requires the barrier to be extremely thin and have a large area. The second pressure, which has only recently been appreciated, is to maintain the mechanical integrity of the barrier in the face of its extreme thinness. The most important tensile stress comes from the pressure within the pulmonary capillaries, which results in a hoop stress. The strength of the barrier can be attributed to the type IV collagen in the extracellular matrix. In addition, the stress is minimized in mammals and birds by complete separation of the pulmonary and systemic circulations. Remarkably, the avian barrier is about 2.5 times thinner than that in mammals and also is much more uniform in thickness. These advantages for gas exchange come about because the avian pulmonary capillaries are unique among air breathers in being mechanically supported externally in addition to the strength that comes from the structure of their walls. This external support comes from epithelial plates that are part of the air capillaries, and the support is available because the terminal air spaces in the avian lung are extremely small due to the flow-through nature of ventilation in contrast to the reciprocating pattern in mammals.

Assessment of Activity-Specific Metabolism of Aquatic Organisms: An Improved System

1992 ◽  
Vol 49 (6) ◽  
pp. 1142-1148 ◽  
Author(s):  
Ronald W. Davies ◽  
Frederick J. Wrona ◽  
V. Kalarani
Keyword(s):  
Oxygen Consumption ◽  
Individual Variation ◽  
Aquatic Organisms ◽  
Size Classes ◽  
Interspecific Differences ◽  
Nephelopsis Obscura ◽  
Highly Sensitive ◽  
Similar Weight ◽  
Flow Through

An improved flow-through respirometer capable of assessing activity-specific metabolism of aquatic organisms is presented and assessed. The system is highly sensitive and versatile, since it continuously monitors and records activity-specific oxygen consumption readings for periods up to 72 h and is capable of detecting differences in metabolism of individual specimens of similar weight. Using this system, we demonstrated individual variation and intraspecific differences in metabolism between two size classes of the freshwater leech Nephelopsis obscura and interspecific differences between N. obscura and another freshwater leech, Erpobdella montezuma, and compared these findings with the metabolism of the amphipod Hyalella montezuma.

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