... in 5 s intervals from the rate of gliding descent. We modeled body density across depth in each dive, revealing high tissue densities and diving lung volumes (DLVs). DLV increased with dive depth in four individuals. We used the buoyancy calculated from dive-specific body-density models and drag...

...Alexandra Venuto; Stacey Thibodeau-Beganny; Josef G. Trapani; Timothy Erickson ABSTRACT Larval zebrafish achieve neutral buoyancy by swimming up to the surface and taking in air through their mouths to inflate their swim bladders. We define this behavior as ‘surfacing’. Little is known about...

... that total lung capacity is overestimated by established allometric relationships, and affirms that body density and net vertical forces influence the cost of diving. Pusa hispida Buoyancy Computed tomography Diving physiology Total lung capacity A key question in comparative physiology...

... (11 km, 1100 bar), theoretically providing buoyancy far beyond the maximum depth of occurrence (3700 m) of sharks. However, Δρ does change significantly with temperature and we show that the combined effects of pressure and temperature can decrease buoyancy of oil by up to 10% between the surface...

... for the brood weight on the anterior portion of their body. For fishes with a compartmentalized swim bladder, gas distribution between the chambers may aid in regulating buoyancy during brooding. To test this hypothesis, we took radiographs of Astatotilapia burtoni to compare the swim bladder morphology...

... and activity by controlling their net buoyancy; however, few buoyancy studies have been conducted on physostomous fish in the wild. We deployed accelerometers on free-ranging channel catfish, Ictalurus punctatus , in both lentic and lotic environments to quantify their swimming activity, and to determine...

... bottlenose whales with data loggers that recorded depth, 3-axis acceleration and speed either with a fly-wheel or from change of depth corrected by pitch angle. We fitted measured values of the change in speed during 5 s descent and ascent glides to a hydrodynamic model of drag and buoyancy forces using...

..., working hypotheses: (1) the urea-based osmoregulatory strategy of chondrichthyans might conflict with the interactive effects of low temperature and high pressure on protein and membrane function at great depth; (2) the reliance on lipid accumulation for buoyancy in chondrichthyans has a unique energetic...

... Anisops deanei does exchange gases with the water. Our results indicate that approximately 20% of O 2 consumed during a dive is obtained directly from the water. Oxygen from the water complements that released from the haemoglobin, extending the period of near-neutral buoyancy and increasing dive duration...

... for this species-rich group to occupy freshwater systems. Using hydromechanical modeling, we show that occurrence in fresh water results in a two- to three-fold increase in negative buoyancy for sharks and rays. This carries the energetic cost of lift production and results in increased buoyancy-dependent...

..., gliding down at slower speeds, and reduced their ascent swimming effort to maintain a nearly constant swimming speed as their buoyancy increased. One per cent of seal density variation over time was found to induce a 20% variation in swimming effort during dives with direct consequences on dive duration...

... efficiency of marine animals is primarily determined by their physiological and mechanical characteristics. This efficiency may be apparent via examination of biomechanical performance (e.g. stroke frequency and amplitude, change in buoyancy or body angle, etc.), which itself may be modulated according...

... 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...

...Matthew R. Stoyek; Frank M. Smith; Roger P. Croll SUMMARY Many teleosts use gas-filled swimbladders to control buoyancy and influence three-dimensional orientation (pitch and roll). However, swimbladder volume, and its contributions to these functions, varies with depth-related pressure according...

... measurements determined by isotope dilution, and therefore have the potential to track changes in body condition of a wide range of freely diving animals. Gliding during ascent and descent clearly increased and stroke rate decreased when buoyancy manipulations aided the direction of vertical transit...

...Tristan C. Dumbarton; Matthew Stoyek; Roger P. Croll; Frank M. Smith SUMMARY Many teleosts actively regulate buoyancy by adjusting gas volume in the swimbladder. In physostomous fishes such as the zebrafish, a connection is maintained between the swimbladder and the oesophagus via the pneumatic...

...Philip G. D. Matthews; Roger S. Seymour SUMMARY Unlike all other diving insects, backswimmers of the genus Anisops can exploit the pelagic zone by temporarily achieving near-neutral buoyancy during the course of a dive. They begin a dive positively buoyant due to the large volume of air carried...

... Alexander, M. R. ( 1990 ). Size, speed and buoyancy adaptations in aquatic animals. Am. Zool. 30 , 189 -196. Brainerd, E. L. ( 1999 ). New perspectives on the evolution of lung ventilation mechanisms in vertebrates. Exp. Biol. Online 4 , 1 -28. Carrier, D. R. ( 1987 ). The evolution...

...Yuuki Watanabe; Eugene A. Baranov; Katsufumi Sato; Yasuhiko Naito; Nobuyuki Miyazaki SUMMARY Buoyancy is one of the primary external forces acting on air-breathing divers and it can affect their swimming energetics. Because the body composition of marine mammals (i.e. the relative amounts of lower...

... organisms maintain upright postures in the water column by one of two mechanisms, stiffness or buoyancy. Turbinaria ornata is a tropical macroalga that uses either buoyancy or flexural stiffness ( EI ), depending on its flow habitat. This study used physical models of T. ornata to compare the effect...