Shape, Drag, and Power in Ammonoid Swimming

Paleobiology ◽  
1992 ◽  
Vol 18 (2) ◽  
pp. 203-220 ◽  
Author(s):  
David K. Jacobs
Keyword(s):  
Oxygen Consumption ◽  
Power Consumption ◽  
Constant Velocity ◽  
Reynolds Numbers ◽  
Energetic Cost ◽  
Shell Shape ◽  
High Current ◽  
Small Thickness ◽  
Limited Dispersal ◽  
High Current Velocity

This study assesses swimming potential in a variety of ammonoid shell shapes on the basis of coefficients of drag (Cd) and the power needed to maintain a constant velocity. Reynolds numbers (Re) relevant to swimming ammonoids, and lower than those previously studied, were examined. Power consumption was scaled to a range of sizes and swimming velocities. Estimates of power available derived from studies of oxygen consumption in modern cephalopods and fish were used to calculate maximum sustainable swimming velocities (MSV).Laterally compressed, small thickness ratio (t. r.) ammonoids, previously assumed to be the most efficient swimmers, do not experience the lowest drag or power consumption at all sizes and velocities. At low values of size and velocity associated with Reynolds numbers below 104, less compressed forms have smaller drag coefficients and reduced power requirements. At hatching a roughly spherical shell shape would have minimized drag in ammonoids; with increasing size, hydrodynamic optima shift toward compressed morphologies.The high energetic cost of ammonoid locomotion may have limited dispersal and excluded ammonoids from high current velocity environments.

scholarly journals Heat increment of feeding in Brunnich's guillemot

1997 ◽  
Vol 200 (12) ◽  
pp. 1757-1763 ◽  
Author(s):  
P Hawkins ◽  
P Butler ◽  
A Woakes ◽  
G Gabrielsen
Keyword(s):  
Oxygen Consumption ◽  
Energetic Cost ◽  
Uria Lomvia ◽  
Deep Body Temperature ◽  
Common Murre ◽  
Heat Increment Of Feeding ◽  
Heat Increment ◽  
Rate Of Oxygen Consumption ◽  
Free Ranging ◽  
Persistent Elevation

The rate of oxygen consumption (O2), respiratory quotient (RQ) and deep body temperature (TB) were recorded during a single, voluntary ingestion of Arctic cod Boreogadus saida (mean mass 18.9+/-1.1 g, s.e.m., N=13) by five postabsorptive Brunnich's guillemots (thick-billed murre, Uria lomvia). The birds were resting in air within their thermoneutral zone, and the fish were refrigerated to 0-2 degreesC. The rate of oxygen consumption increased by a factor of 1.4 during the first few minutes after ingestion, but there was no significant change in TB. Mean rate of oxygen consumption returned to preingestive levels 85 min after the birds ate the fish. The telemetered temperature of one fish reached TB within 20 min. This suggests that the persistent elevation in O2 over the next hour corresponded to the obligatory component of the heat increment of feeding (HIF) and was not related to heating the fish. Abdominal temperature increases after diving bouts in free-ranging common guillemots (common murre, Uria aalge) are possibly achieved through the HIF, since meals are processed at sea. Of the increase in O2 measured in the laboratory, it is calculated that 30 % is required to heat the fish, while 70 % is due to the HIF. In free-ranging birds, the excess heat provided by the HIF could contribute 6 % of the daily energy expenditure. This suggests that the HIF augments heat production in Uria spp. and thus reduces the energetic cost of thermoregulation.

Energetic cost of active branchial ventilation in the sharksucker, Echeneis naucrates

1983 ◽  
Vol 103 (1) ◽  
pp. 185-192 ◽  
Author(s):  
J. F. Steffensen ◽  
J. P. Lomholt
Keyword(s):  
Oxygen Consumption ◽  
Water Velocity ◽  
Moving Object ◽  
Water Current ◽  
Energetic Cost ◽  
Gill Ventilation

1. Sharksuckers use active branchial ventilation when swimming or at rest in stationary water. When attached to a moving object or when placed in a water current, they shift to ram gill ventilation as water velocity exceeds a certain threshold. 2. Water velocities required for the transition from active to ram gill ventilation were from 10–50 cm s-1, depending on the size of the fish. 3. Oxygen consumption increased between 3.7 and 5.7% when the fish shifted from ram gill ventilation to active branchial pumping. 4. When water velocity was increased beyond the threshold for ram gill ventilation, no further increase in oxygen consumption was observed. 5. It is concluded that the energetic cost of active ventilation in sharksuckers is lower than has previously been reported for fish in general.

Microhabitat characteristics and reproductive status of male Euchordodes nigromaculatus (Nematomorpha)

1999 ◽  
Vol 73 (1) ◽  
pp. 91-93 ◽  
Author(s):  
F. Thomas ◽  
A. Schmidt-Rhaesa ◽  
R. Poulin
Keyword(s):  
New Zealand ◽  
Current Velocity ◽  
Physical Characteristics ◽  
Reproductive Status ◽  
Mountain Stream ◽  
High Current ◽  
Free Living ◽  
High Current Velocity

In a sample of 61 free-living, postparasitic male Euchordodes nigromaculatus collected from a mountain stream in New Zealand, we found that only large males are found in areas of high current velocity. Thirty-five of the 61 males still contained gametes; these worms were found in wider, deeper, and slower-flowing parts of the stream relative to worms that had released their gametes. These results suggest that the physical characteristics of the immediate microhabitat of male worms can determine their probability of mating.

Energetic cost of locomotion in the tammar wallaby

1992 ◽  
Vol 262 (5) ◽  
pp. R771-R778 ◽  
Author(s):  
R. V. Baudinette ◽  
G. K. Snyder ◽  
P. B. Frappell
Keyword(s):  
Oxygen Consumption ◽  
Blood Lactate ◽  
Body Mass ◽  
Energy Cost ◽  
Physiological Adaptation ◽  
Energetic Cost ◽  
Cost Of Locomotion ◽  
Lactate Levels ◽  
Energy Cost Of Locomotion ◽  
Blood Lactate Levels

Rates of oxygen consumption and blood lactate levels were measured in tammar wallabies (Macropus eugenii) trained to hop on a treadmill. In addition, the work required to overcome wind resistance during forward locomotion was measured in a wind tunnel. Up to approximately 2.0 m/s, rates of oxygen consumption increased linearly with speed and were not significantly different from rates of oxygen consumption for a quadruped of similar body mass. Between 2.0 and 9.4 m/s, rates of oxygen consumption were independent of hopping speed, and between 3.9 and 7.9 m/s, the range over which samples were obtained, blood lactate levels were low (0.83 +/- 0.13 mmol.min-1.kg-1) and did not increase with hopping speed. The work necessary to overcome drag increased exponentially with speed but increased the energy cost of locomotion by only 10% at the average speed attained by our fast hoppers. Thus, during hopping, the energy cost of locomotion is effectively independent of speed. At rates of travel observed in the field, the estimated energy cost of transport in large macropods is less than one-third the cost for a quadruped of equivalent body mass. The energetic savings associated with this unique form of locomotion may have been an important physiological adaptation, enabling large macropods to efficiently cover the distances necessary to forage in the semiarid landscapes of Australia.

Effects of Buoyancy on Heat Transfer and Oxygen Consumption in Fuel-Thermal-Stability Studies

1994 ◽  
Author(s):  
Viswanath R. Katta ◽  
James W. Blust ◽  
Theodore F. Williams ◽  
Charles R. Martel
Keyword(s):  
Heat Transfer ◽  
Thermal Stability ◽  
Oxygen Consumption ◽  
Test Section ◽  
Reynolds Numbers ◽  
Momentum Equation ◽  
Flow Rates ◽  
Fuel Flow ◽  
Block Temperature ◽  
Bottom To Top

A unique methodology is used to investigate the effects of gravity on fuel flowing through the small-bore heated tubes that are often used in the study of fuel-thermal-stability characteristics. The copper block that houses the fuel tube (or test section) is located on a swivel, and experiments are conducted for different tube orientations namely; horizontal, vertical with flow from bottom to top and vice versa. Results obtained for different fuel-flow rates and block temperatures are discussed. An axisymmetric, time-dependent numerical model is used to simulate the flow patterns in the test section. This model solves momentum, energy, species and k-ε turbulence equations. The buoyancy term is included in the axial-momentum equation. Natural flow resulting from buoyancy was found to have a significant effect on heat transfer and oxygen consumption for fuel-flow rates up to 100 cc/min (Reynolds numbers up to 2300). Flow instabilities were observed when the fuel was flowing downward in a vertically mounted test section. The effect of block temperature and flow rate on these instabilities was also studied.

scholarly journals The energetic costs of living in the surf and impacts on zonation of shells occupied by hermit crabs

2020 ◽  
Vol 223 (16) ◽  
pp. jeb222703 ◽  
Author(s):  
Guillermina Alcaraz ◽  
Brenda Toledo ◽  
Luis M. Burciaga
Keyword(s):  
Water Flow ◽  
Wave Action ◽  
Hermit Crabs ◽  
Energetic Cost ◽  
Shell Shape ◽  
Energetic Costs ◽  
Shell Size ◽  
Conical Shells ◽  
Drag Forces ◽  
Submerged Body

ABSTRACTCrashing waves create a hydrodynamic gradient in which the most challenging effects occur at the wave breaking zone and decrease towards the upper protected tide pools. Hydrodynamic forces depend on the shape of the submerged body; streamlined shapes decrease drag forces compared with bluff or globose bodies. Unlike other animals, hermit crabs can choose their shell shape to cope with the effects of water flow. Hermit crabs occupy larger and heavier shells (conical shape) in wave-exposed sites than those used in protected areas (globose shape). First, we investigated whether a behavioral choice could explain the shells used in sites with different wave action. Then, we experimentally tested whether the shells most frequently used in sites with different wave action reduce the energetic cost of coping with water flow. Metabolic rate was measured using a respirometric system fitted with propellers in opposite walls to generate bidirectional water flow. The choice of shell size when a large array of sizes are available was consistent with the shell size used in different intertidal sites; hermit crabs chose heavier conical shells in water flow conditions than in still water, and the use of heavy conical shells reduced the energetic cost of coping with water motion. In contrast to conical shells, small globose shells imposed lower energy costs of withstanding water flow than large globose shells. The size and type of shells used in different zones of the rocky shore were consistent with an adaptive response to reduce the energetic costs of withstanding wave action.

scholarly journals Energetic cost of locomotion as a function of ambient temperature and during growth in the marsupial Potorous tridactylus.

1993 ◽  
Vol 174 (1) ◽  
pp. 81-95
Author(s):  
R V Baudinette ◽  
E A Halpern ◽  
D S Hinds
Keyword(s):  
Oxygen Consumption ◽  
Ambient Temperature ◽  
Multiple Regression ◽  
Stride Length ◽  
Energy Use ◽  
Linear Increase ◽  
Stride Frequency ◽  
Energetic Cost ◽  
Cost Of Transport ◽  
Cost Of Locomotion

In the marsupial, the potoroo, multiple regression analysis shows that ambient temperature makes a minor (2%) contribution towards variation in oxygen consumption with speed. This suggests that the heat generated during running is substituted for heat which would otherwise have to be generated for temperature regulation. Maximum levels of oxygen consumption are also temperature-independent over the range 5-25 degrees C, but plasma lactate concentrations at the conclusion of exercise significantly increase with ambient temperature. Adult potoroos show a linear increase in oxygen consumption with speed, and multiple regression indicates that the most significant factor affecting energy use during running is stride length. Juvenile potoroos have an incremental cost of locomotion about 40% lower than that predicted on the basis of body mass. The smaller animals meet the demands of increasing speed by increasing stride length rather than stride frequency, as would be expected in a smaller species. Our results show that juvenile potoroos diverge significantly from models based only on adult animals in incremental changes in stride frequency, length and the cost of transport, suggesting that they are not simply scaled-down adults.

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