Sink fast and swim harder! Round-trip cost-of-transport for buoyant divers
Efficient locomotion between prey resources at depth and oxygen at the surface is crucial for breath-hold divers to maximize time spent in the foraging layer, and thereby net energy intake rates. The body density of divers, which changes with body condition, determines the apparent weight (buoyancy)...
Published in: | Journal of Experimental Biology |
---|---|
Main Authors: | , , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
2012
|
Subjects: | |
Online Access: | https://research-portal.st-andrews.ac.uk/en/researchoutput/sink-fast-and-swim-harder-roundtrip-costoftransport-for-buoyant-divers(0a8fa431-ab70-4b3c-843d-f496a8ed0d63).html https://doi.org/10.1242/jeb.070128 |
id |
ftunstandrewcris:oai:research-portal.st-andrews.ac.uk:publications/0a8fa431-ab70-4b3c-843d-f496a8ed0d63 |
---|---|
record_format |
openpolar |
spelling |
ftunstandrewcris:oai:research-portal.st-andrews.ac.uk:publications/0a8fa431-ab70-4b3c-843d-f496a8ed0d63 2024-06-23T07:52:29+00:00 Sink fast and swim harder! Round-trip cost-of-transport for buoyant divers Miller, Patrick Biuw, Martin Watanabe, Yuuki Y. Thompson, David Fedak, Mike 2012-10 https://research-portal.st-andrews.ac.uk/en/researchoutput/sink-fast-and-swim-harder-roundtrip-costoftransport-for-buoyant-divers(0a8fa431-ab70-4b3c-843d-f496a8ed0d63).html https://doi.org/10.1242/jeb.070128 eng eng https://research-portal.st-andrews.ac.uk/en/researchoutput/sink-fast-and-swim-harder-roundtrip-costoftransport-for-buoyant-divers(0a8fa431-ab70-4b3c-843d-f496a8ed0d63).html info:eu-repo/semantics/restrictedAccess Miller , P , Biuw , M , Watanabe , Y Y , Thompson , D & Fedak , M 2012 , ' Sink fast and swim harder! Round-trip cost-of-transport for buoyant divers ' , Journal of Experimental Biology , vol. 215 , no. 20 , pp. 3622-3630 . https://doi.org/10.1242/jeb.070128 WHALES DIVING BEHAVIOR STRATEGIES drag LOCOMOTION SPEED swimming gait buoyancy BREATH-HOLD DIVERS cost-of-transport BODY DENSITY STROKING PATTERNS NORTHERN ELEPHANT SEALS DEPTH article 2012 ftunstandrewcris https://doi.org/10.1242/jeb.070128 2024-06-13T00:36:41Z Efficient locomotion between prey resources at depth and oxygen at the surface is crucial for breath-hold divers to maximize time spent in the foraging layer, and thereby net energy intake rates. The body density of divers, which changes with body condition, determines the apparent weight (buoyancy) of divers, which may affect round-trip cost-of-transport (COT) between the surface and depth. We evaluated alternative predictions from external-work and actuator-disc theory of how non-neutral buoyancy affects round-trip COT to depth, and the minimum COT speed for steady-state vertical transit. Not surprisingly, the models predict that one-way COT decreases (increases) when buoyancy aids (hinders) one-way transit. At extreme deviations from neutral buoyancy, gliding at terminal velocity is the minimum COT strategy in the direction aided by buoyancy. In the transit direction hindered by buoyancy, the external-work model predicted that minimum COT speeds would not change at greater deviations from neutral buoyancy, but minimum COT speeds were predicted to increase under the actuator disc model. As previously documented for grey seals, we found that vertical transit rates of 36 elephant seals increased in both directions as body density deviated from neutral buoyancy, indicating that actuator disc theory may more closely predict the power requirements of divers affected by gravity than an external work model. For both models, minor deviations from neutral buoyancy did not affect minimum COT speed or round-trip COT itself. However, at body-density extremes, both models predict that savings in the aided direction do not fully offset the increased COT imposed by the greater thrusting required in the hindered direction. Article in Journal/Newspaper Elephant Seals University of St Andrews: Research Portal Journal of Experimental Biology 215 20 3622 3630 |
institution |
Open Polar |
collection |
University of St Andrews: Research Portal |
op_collection_id |
ftunstandrewcris |
language |
English |
topic |
WHALES DIVING BEHAVIOR STRATEGIES drag LOCOMOTION SPEED swimming gait buoyancy BREATH-HOLD DIVERS cost-of-transport BODY DENSITY STROKING PATTERNS NORTHERN ELEPHANT SEALS DEPTH |
spellingShingle |
WHALES DIVING BEHAVIOR STRATEGIES drag LOCOMOTION SPEED swimming gait buoyancy BREATH-HOLD DIVERS cost-of-transport BODY DENSITY STROKING PATTERNS NORTHERN ELEPHANT SEALS DEPTH Miller, Patrick Biuw, Martin Watanabe, Yuuki Y. Thompson, David Fedak, Mike Sink fast and swim harder! Round-trip cost-of-transport for buoyant divers |
topic_facet |
WHALES DIVING BEHAVIOR STRATEGIES drag LOCOMOTION SPEED swimming gait buoyancy BREATH-HOLD DIVERS cost-of-transport BODY DENSITY STROKING PATTERNS NORTHERN ELEPHANT SEALS DEPTH |
description |
Efficient locomotion between prey resources at depth and oxygen at the surface is crucial for breath-hold divers to maximize time spent in the foraging layer, and thereby net energy intake rates. The body density of divers, which changes with body condition, determines the apparent weight (buoyancy) of divers, which may affect round-trip cost-of-transport (COT) between the surface and depth. We evaluated alternative predictions from external-work and actuator-disc theory of how non-neutral buoyancy affects round-trip COT to depth, and the minimum COT speed for steady-state vertical transit. Not surprisingly, the models predict that one-way COT decreases (increases) when buoyancy aids (hinders) one-way transit. At extreme deviations from neutral buoyancy, gliding at terminal velocity is the minimum COT strategy in the direction aided by buoyancy. In the transit direction hindered by buoyancy, the external-work model predicted that minimum COT speeds would not change at greater deviations from neutral buoyancy, but minimum COT speeds were predicted to increase under the actuator disc model. As previously documented for grey seals, we found that vertical transit rates of 36 elephant seals increased in both directions as body density deviated from neutral buoyancy, indicating that actuator disc theory may more closely predict the power requirements of divers affected by gravity than an external work model. For both models, minor deviations from neutral buoyancy did not affect minimum COT speed or round-trip COT itself. However, at body-density extremes, both models predict that savings in the aided direction do not fully offset the increased COT imposed by the greater thrusting required in the hindered direction. |
format |
Article in Journal/Newspaper |
author |
Miller, Patrick Biuw, Martin Watanabe, Yuuki Y. Thompson, David Fedak, Mike |
author_facet |
Miller, Patrick Biuw, Martin Watanabe, Yuuki Y. Thompson, David Fedak, Mike |
author_sort |
Miller, Patrick |
title |
Sink fast and swim harder! Round-trip cost-of-transport for buoyant divers |
title_short |
Sink fast and swim harder! Round-trip cost-of-transport for buoyant divers |
title_full |
Sink fast and swim harder! Round-trip cost-of-transport for buoyant divers |
title_fullStr |
Sink fast and swim harder! Round-trip cost-of-transport for buoyant divers |
title_full_unstemmed |
Sink fast and swim harder! Round-trip cost-of-transport for buoyant divers |
title_sort |
sink fast and swim harder! round-trip cost-of-transport for buoyant divers |
publishDate |
2012 |
url |
https://research-portal.st-andrews.ac.uk/en/researchoutput/sink-fast-and-swim-harder-roundtrip-costoftransport-for-buoyant-divers(0a8fa431-ab70-4b3c-843d-f496a8ed0d63).html https://doi.org/10.1242/jeb.070128 |
genre |
Elephant Seals |
genre_facet |
Elephant Seals |
op_source |
Miller , P , Biuw , M , Watanabe , Y Y , Thompson , D & Fedak , M 2012 , ' Sink fast and swim harder! Round-trip cost-of-transport for buoyant divers ' , Journal of Experimental Biology , vol. 215 , no. 20 , pp. 3622-3630 . https://doi.org/10.1242/jeb.070128 |
op_relation |
https://research-portal.st-andrews.ac.uk/en/researchoutput/sink-fast-and-swim-harder-roundtrip-costoftransport-for-buoyant-divers(0a8fa431-ab70-4b3c-843d-f496a8ed0d63).html |
op_rights |
info:eu-repo/semantics/restrictedAccess |
op_doi |
https://doi.org/10.1242/jeb.070128 |
container_title |
Journal of Experimental Biology |
container_volume |
215 |
container_issue |
20 |
container_start_page |
3622 |
op_container_end_page |
3630 |
_version_ |
1802643801022398464 |