1
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Ponganis PJ, Williams CL, Kendall-Bar JM. Blood oxygen transport and depletion in diving emperor penguins. J Exp Biol 2024; 227:jeb246832. [PMID: 38390686 PMCID: PMC11006389 DOI: 10.1242/jeb.246832] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Accepted: 02/06/2024] [Indexed: 02/24/2024]
Abstract
Oxygen store management underlies dive performance and is dependent on the slow heart rate and peripheral vasoconstriction of the dive response to control tissue blood flow and oxygen uptake. Prior research has revealed two major patterns of muscle myoglobin saturation profiles during dives of emperor penguins. In Type A profiles, myoglobin desaturated rapidly, consistent with minimal muscle blood flow and low tissue oxygen uptake. Type B profiles, with fluctuating and slower declines in myoglobin saturation, were consistent with variable tissue blood flow patterns and tissue oxygen uptake during dives. We examined arterial and venous blood oxygen profiles to evaluate blood oxygen extraction and found two primary patterns of venous hemoglobin desaturation that complemented corresponding myoglobin saturation profiles. Type A venous profiles had a hemoglobin saturation that (a) increased/plateaued for most of a dive's duration, (b) only declined during the latter stages of ascent, and (c) often became arterialized [arterio-venous (a-v) shunting]. In Type B venous profiles, variable but progressive hemoglobin desaturation profiles were interrupted by inflections in the profile that were consistent with fluctuating tissue blood flow and oxygen uptake. End-of-dive saturation of arterial and Type A venous hemoglobin saturation profiles were not significantly different, but did differ from those of Type B venous profiles. These findings provide further support that the dive response of emperor penguins is a spectrum of cardiac and vascular components (including a-v shunting) that are dependent on the nature and demands of a given dive and even of a given segment of a dive.
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Affiliation(s)
- Paul J. Ponganis
- Center for Marine Biotechnology & Biomedicine, Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA 92093-0204, USA
| | - Cassondra L. Williams
- National Marine Mammal Foundation, 2240 Shelter Island Drive, San Diego, CA 92106, USA
| | - Jessica M. Kendall-Bar
- Center for Marine Biotechnology & Biomedicine, Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA 92093-0204, USA
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2
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Borque-Espinosa A, Rode KD, Ferrero-Fernández D, Forte A, Capaccioni-Azzati R, Fahlman A. Subsurface swimming and stationary diving are metabolically cheap in adult Pacific walruses (Odobenus rosmarus divergens). J Exp Biol 2021; 224:273381. [PMID: 34746957 DOI: 10.1242/jeb.242993] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Accepted: 11/02/2021] [Indexed: 11/20/2022]
Abstract
Walruses rely on sea-ice to efficiently forage and rest between diving bouts while maintaining proximity to prime foraging habitat. Recent declines in summer sea ice have resulted in walruses hauling out on land where they have to travel farther to access productive benthic habitat while potentially increasing energetic costs. Despite the need to better understand the impact of sea ice loss on energy expenditure, knowledge about metabolic demands of specific behaviours in walruses is scarce. In the present study, 3 adult female Pacific walruses (Odobenus rosmarus divergens) participated in flow-through respirometry trials to measure metabolic rates while floating inactive at the water surface during a minimum of 5 min, during a 180-second stationary dive, and while swimming horizontally underwater for ∼90 m. Metabolic rates during stationary dives (3.82±0.56 l O2 min-1) were lower than those measured at the water surface (4.64±1.04 l O2 min-1), which did not differ from rates measured during subsurface swimming (4.91±0.77 l O2 min-1). Thus, neither stationary diving nor subsurface swimming resulted in metabolic rates above those exhibited by walruses at the water surface. These results suggest that walruses minimize their energetic investment during underwater behaviours as reported for other marine mammals. Although environmental factors experienced by free-ranging walruses (e.g., winds or currents) likely affect metabolic rates, our results provide important information for understanding how behavioural changes affect energetic costs and can be used to improve bioenergetics models aimed at predicting the metabolic consequences of climate change on walruses.
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Affiliation(s)
- Alicia Borque-Espinosa
- Universitat de València, Av. de Blasco Ibáñez 13, 46010 Valencia, Spain.,Fundación Oceanogràfic de la Comunitat Valenciana, Gran Vía Marqués del Turia 19, 46005 Valencia, Spain
| | - Karyn D Rode
- U.S. Geological Survey Alaska Science Center, , 4210 University Dr, Anchorage, 99508 AK, USA
| | | | - Anabel Forte
- Universitat de València, Av. de Blasco Ibáñez 13, 46010 Valencia, Spain
| | | | - Andreas Fahlman
- Fundación Oceanogràfic de la Comunitat Valenciana, Gran Vía Marqués del Turia 19, 46005 Valencia, Spain.,Global Diving Research, Inc. Ottawa, K2J 5E8 ON, Canada
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3
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Robinson NJ, García-Párraga D, Stacy BA, Costidis AM, Blanco GS, Clyde-Brockway CE, Haas HL, Harms CA, Patel SH, Stacy NI, Fahlman A. A Baseline Model For Estimating the Risk of Gas Embolism in Sea Turtles During Routine Dives. Front Physiol 2021; 12:678555. [PMID: 34539425 PMCID: PMC8440993 DOI: 10.3389/fphys.2021.678555] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Accepted: 07/22/2021] [Indexed: 11/13/2022] Open
Abstract
Sea turtles, like other air-breathing diving vertebrates, commonly experience significant gas embolism (GE) when incidentally caught at depth in fishing gear and brought to the surface. To better understand why sea turtles develop GE, we built a mathematical model to estimate partial pressures of N2 (PN2), O2 (PO2), and CO2 (PCO2) in the major body-compartments of diving loggerheads (Caretta caretta), leatherbacks (Dermochelys coriacea), and green turtles (Chelonia mydas). This model was adapted from a published model for estimating gas dynamics in marine mammals and penguins. To parameterize the sea turtle model, we used values gleaned from previously published literature and 22 necropsies. Next, we applied this model to data collected from free-roaming individuals of the three study species. Finally, we varied body-condition and cardiac output within the model to see how these factors affected the risk of GE. Our model suggests that cardiac output likely plays a significant role in the modulation of GE, especially in the deeper diving leatherback turtles. This baseline model also indicates that even during routine diving behavior, sea turtles are at high risk of GE. This likely means that turtles have additional behavioral, anatomical, and/or physiologic adaptions that serve to reduce the probability of GE but were not incorporated in this model. Identifying these adaptations and incorporating them into future iterations of this model will further reveal the factors driving GE in sea turtles.
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Affiliation(s)
- Nathan J. Robinson
- Department of Research, Fundación Oceanogràfic de la Comunidad Valenciana, Valencia, Spain
| | - Daniel García-Párraga
- Department of Research, Fundación Oceanogràfic de la Comunidad Valenciana, Valencia, Spain
| | - Brian A. Stacy
- National Oceanic and Atmospheric Administration, National Marine Fisheries Service, Office of Protected Resources, University of Florida (duty station), Washington, DC, United States
| | | | - Gabriela S. Blanco
- Instituto de Biología de Organismos Marinos (IBIOMAR-CCT CONICET-CENPAT), Puerto Madryn, Argentina
| | | | - Heather L. Haas
- Northeast Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, Woods Hole, MA, United States
| | - Craig A. Harms
- Department of Clinical Sciences and Center for Marine Sciences and Technology, North Carolina State University, Raleigh, NC, United States
| | - Samir H. Patel
- Coonamessett Farm Foundation, East Falmouth, MA, United States
| | - Nicole I. Stacy
- Department of Comparative, Diagnostic, and Population Medicine, College of Veterinary Medicine, University of Florida, Gainesville, FL, United States
| | - Andreas Fahlman
- Department of Research, Fundación Oceanogràfic de la Comunidad Valenciana, Valencia, Spain
- Global Diving Research, Inc., Ottawa, ON, Canada
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4
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Lipid signature of neural tissues of marine and terrestrial mammals: consistency across species and habitats. J Comp Physiol B 2021; 191:815-829. [PMID: 33973058 DOI: 10.1007/s00360-021-01373-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Revised: 03/24/2021] [Accepted: 04/20/2021] [Indexed: 02/07/2023]
Abstract
Marine mammals are exposed to O2-limitation and increased N2 gas concentrations as they dive to exploit habitat and food resources. The lipid-rich tissues (blubber, acoustic, neural) are of particular concern as N2 is five times more soluble in lipid than in blood or muscle, creating body compartments that can become N2 saturated, possibly leading to gas emboli upon surfacing. We characterized lipids in the neural tissues of marine mammals to determine whether they have similar lipid profiles compared to terrestrial mammals. Lipid profiles (lipid content, lipid class composition, and fatty acid signatures) were determined in the neural tissues of 12 cetacean species with varying diving regimes, and compared to two species of terrestrial mammals. Neural tissue lipid profile was not significantly different in marine versus terrestrial mammals across tissue types. Within the marine species, average dive depth was not significantly associated with the lipid profile of cervical spinal cord. Across species, tissue type (brain, spinal cord, and spinal nerve) was a significant factor in lipid profile, largely due to the presence of storage lipids (triacylglycerol and wax ester/sterol ester) in spinal nerve tissue only. The stability of lipid signatures within the neural tissue types of terrestrial and marine species, which display markedly different dive behaviors, points to the consistent role of lipids in these tissues. These findings indicate that despite large differences in the level of N2 gas exposure by dive type in the species examined, the lipids of neural tissues likely do not have a neuroprotective role in marine mammals.
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5
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Gabler-Smith MK, Westgate AJ, Koopman HN. Fatty acid composition and N 2 solubility in triacylglycerol-rich adipose tissue: the likely importance of intact molecular structure. ACTA ACUST UNITED AC 2020; 223:jeb.216770. [PMID: 32001545 DOI: 10.1242/jeb.216770] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Accepted: 01/23/2020] [Indexed: 12/25/2022]
Abstract
Diving tetrapods (sea turtles, seabirds and marine mammals) are a biologically diverse group, yet all are under similar constraints: oxygen limitation and increased hydrostatic pressure at depth. Adipose tissue is important in the context of diving because nitrogen gas (N2) is five times more soluble in fat than in blood, creating a potential N2 sink in diving animals. Previous research demonstrates that unusual lipid composition [waxes and short-chained fatty acids (FA)] in adipose tissue of some whales leads to increased N2 solubility. We evaluated the N2 solubility of adipose tissue from 12 species of diving tetrapods lacking these unusual lipids to explore whether solubility in this tissue can be linked to lipid structure. Across all taxonomic groups, the same eight FA accounted for 70-80% of the entire lipid profile; almost all adipose tissues were dominated by monounsaturated FA (40.2-67.4 mol%). However, even with consistent FA profiles, there was considerable variability in N2 solubility, ranging from 0.051±0.003 to 0.073±0.004 ml N2 ml-1 oil. Interestingly, differences in N2 solubility could not be attributed to taxonomic group (P=0.06) or FA composition (P>0.10). These results lead to two main conclusions: (1) in triacylglycerol-only adipose tissues, the FA pool itself may not have a strong influence on N2 solubility; and (2) samples with similar FA profiles can have different N2 solubility values, suggesting that 3D arrangement of individual FA within a triacylglycerol molecule may have important roles in determining N2 solubility.
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Affiliation(s)
- Molly K Gabler-Smith
- University of North Carolina Wilmington, 601 S. College Road, Wilmington, NC 28403, USA .,Harvard Museum of Comparative Zoology, 26 Oxford Street, Cambridge, MA 02138, USA
| | - Andrew J Westgate
- University of North Carolina Wilmington, 601 S. College Road, Wilmington, NC 28403, USA
| | - Heather N Koopman
- University of North Carolina Wilmington, 601 S. College Road, Wilmington, NC 28403, USA
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6
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Bernaldo de Quirós Y, Fernandez A, Baird RW, Brownell RL, Aguilar de Soto N, Allen D, Arbelo M, Arregui M, Costidis A, Fahlman A, Frantzis A, Gulland FMD, Iñíguez M, Johnson M, Komnenou A, Koopman H, Pabst DA, Roe WD, Sierra E, Tejedor M, Schorr G. Advances in research on the impacts of anti-submarine sonar on beaked whales. Proc Biol Sci 2020; 286:20182533. [PMID: 30963955 DOI: 10.1098/rspb.2018.2533] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Mass stranding events (MSEs) of beaked whales (BWs) were extremely rare prior to the 1960s but increased markedly after the development of naval mid-frequency active sonar (MFAS). The temporal and spatial associations between atypical BW MSEs and naval exercises were first observed in the Canary Islands, Spain, in the mid-1980s. Further research on BWs stranded in association with naval exercises demonstrated pathological findings consistent with decompression sickness (DCS). A 2004 ban on MFASs around the Canary Islands successfully prevented additional BW MSEs in the region, but atypical MSEs have continued in other places of the world, especially in the Mediterranean Sea, with examined individuals showing DCS. A workshop held in Fuerteventura, Canary Islands, in September 2017 reviewed current knowledge on BW atypical MSEs associated with MFAS. Our review suggests that the effects of MFAS on BWs vary among individuals or populations, and predisposing factors may contribute to individual outcomes. Spatial management specific to BW habitat, such as the MFAS ban in the Canary Islands, has proven to be an effective mitigation tool and mitigation measures should be established in other areas taking into consideration known population-level information.
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Affiliation(s)
- Y Bernaldo de Quirós
- 1 Institute of Animal Health, University of Las Palmas de Gran Canaria, Veterinary School , C/Transmontaña s/n, 35416, Arucas, Las Palmas , Spain
| | - A Fernandez
- 1 Institute of Animal Health, University of Las Palmas de Gran Canaria, Veterinary School , C/Transmontaña s/n, 35416, Arucas, Las Palmas , Spain
| | - R W Baird
- 2 Cascadia Research Collective , 218½ W. 4th Avenue, Olympia, WA 98501 , USA
| | - R L Brownell
- 3 NOAA Fisheries, Southwest Fisheries Science Center , Monterey, CA 93940 , USA
| | - N Aguilar de Soto
- 4 BIOECOMAC. Dept. Animal Biology, Geology and Edaphology, University of La Laguna , Tenerife , Spain
| | - D Allen
- 5 US Marine Mammal Commission , 4340 East-West Highway, Suite 700, Bethesda, MD 20814 , USA
| | - M Arbelo
- 1 Institute of Animal Health, University of Las Palmas de Gran Canaria, Veterinary School , C/Transmontaña s/n, 35416, Arucas, Las Palmas , Spain
| | - M Arregui
- 1 Institute of Animal Health, University of Las Palmas de Gran Canaria, Veterinary School , C/Transmontaña s/n, 35416, Arucas, Las Palmas , Spain
| | - A Costidis
- 6 Virginia Aquarium & Marine Science Center Stranding Response Program , 717 General Booth Blvd, Virginia Beach, VA 23451 , USA
| | - A Fahlman
- 7 Fundación Oceanogràfic de la Comunitat Valenciana , Gran Vía Marqués del Turia 19, 46005, Valencia , Spain
| | - A Frantzis
- 8 Pelagos Cetacean Research Institute , Terpsichoris 21, 16671 Vouliagmeni , Greece
| | - F M D Gulland
- 5 US Marine Mammal Commission , 4340 East-West Highway, Suite 700, Bethesda, MD 20814 , USA.,9 The Marine Mammal Center , 2000 Bunker Road, Sausalito, CA 94965 , USA
| | - M Iñíguez
- 10 Fundación Cethus and WDC , Cap J. Bermúdez 1598, (1636), Olivos, Prov. Buenos Aires , Argentina
| | - M Johnson
- 11 Sea Mammal Research Unit, University of St Andrews , St Andrews , UK
| | - A Komnenou
- 12 School of Veterinary Medicine, Aristotle University of Thessaloniki , Thessaloniki , Greece
| | - H Koopman
- 13 Department of Biology and Marine Biology, University of North Carolina Wilmington , Wilmington, NC 28403 , USA
| | - D A Pabst
- 13 Department of Biology and Marine Biology, University of North Carolina Wilmington , Wilmington, NC 28403 , USA
| | - W D Roe
- 14 Massey University , Palmerston North, PN4222 , New Zealand
| | - E Sierra
- 1 Institute of Animal Health, University of Las Palmas de Gran Canaria, Veterinary School , C/Transmontaña s/n, 35416, Arucas, Las Palmas , Spain
| | - M Tejedor
- 15 Canary Islands Stranding Network , Irlanda 7, Playa Blanca, 35580, Lanzarote , Spain
| | - G Schorr
- 16 Marine Ecology & Telemetry Research , 2468 Camp McKenzie Tr NW, Seabeck, WA 98380 , USA
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7
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Enstipp MR, Bost CA, Le Bohec C, Bost C, Laesser R, Le Maho Y, Weimerskirch H, Handrich Y. The dive performance of immature king penguins following their annual molt suggests physiological constraints. J Exp Biol 2019; 222:222/20/jeb208900. [DOI: 10.1242/jeb.208900] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Accepted: 09/17/2019] [Indexed: 11/20/2022]
Abstract
ABSTRACT
Like all birds, penguins undergo periodic molt, during which they replace old feathers. However, unlike other birds, penguins replace their entire plumage within a short period while fasting ashore. During molt, king penguins (Aptenodytes patagonicus) lose half of their initial body mass, most importantly their insulating subcutaneous fat and half of their pectoral muscle mass. The latter might challenge their capacity to generate and sustain a sufficient mechanical power output to swim to distant food sources and propel themselves to great depth for successful prey capture. To investigate the effects of the annual molt fast on their dive/foraging performance, we studied various dive/foraging parameters and peripheral temperature patterns in immature king penguins across two molt cycles, after birds had spent their first and second year at sea, using implanted data-loggers. We found that the dive/foraging performance of immature king penguins was significantly reduced during post-molt foraging trips. Dive and bottom duration for a given depth were shorter during post-molt and post-dive surface interval duration was longer, reducing overall dive efficiency and underwater foraging time. We attribute this decline to the severe physiological changes that birds undergo during their annual molt. Peripheral temperature patterns differed greatly between pre- and post-molt trips, indicating the loss of the insulating subcutaneous fat layer during molt. Peripheral perfusion, as inferred from peripheral temperature, was restricted to short periods at night during pre-molt but occurred throughout extended periods during post-molt, reflecting the need to rapidly deposit an insulating fat layer during the latter period.
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Affiliation(s)
- Manfred R. Enstipp
- Université de Strasbourg, CNRS, IPHC UMR 7178, F-67000 Strasbourg, France
- Centre d'Etudes Biologiques de Chizé, CNRS, UMR 7372, 79360 Villiers en Bois, France
| | - Charles-André Bost
- Centre d'Etudes Biologiques de Chizé, CNRS, UMR 7372, 79360 Villiers en Bois, France
| | - Céline Le Bohec
- Université de Strasbourg, CNRS, IPHC UMR 7178, F-67000 Strasbourg, France
- Centre Scientifique de Monaco, Département de Biologie Polaire, MC 98000, Monaco
| | - Caroline Bost
- Centre d'Etudes Biologiques de Chizé, CNRS, UMR 7372, 79360 Villiers en Bois, France
| | - Robin Laesser
- Université de Strasbourg, CNRS, IPHC UMR 7178, F-67000 Strasbourg, France
| | - Yvon Le Maho
- Université de Strasbourg, CNRS, IPHC UMR 7178, F-67000 Strasbourg, France
- Centre Scientifique de Monaco, Département de Biologie Polaire, MC 98000, Monaco
| | - Henri Weimerskirch
- Centre d'Etudes Biologiques de Chizé, CNRS, UMR 7372, 79360 Villiers en Bois, France
| | - Yves Handrich
- Université de Strasbourg, CNRS, IPHC UMR 7178, F-67000 Strasbourg, France
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8
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Fahlman A, Brodsky M, Miedler S, Dennison S, Ivančić M, Levine G, Rocho-Levine J, Manley M, Rocabert J, Borque-Espinosa A. Ventilation and gas exchange before and after voluntary static surface breath-holds in clinically healthy bottlenose dolphins, Tursiops truncatus. ACTA ACUST UNITED AC 2019; 222:jeb.192211. [PMID: 30760549 DOI: 10.1242/jeb.192211] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Accepted: 02/05/2019] [Indexed: 01/14/2023]
Abstract
We measured respiratory flow (V̇), breathing frequency (f R), tidal volume (V T), breath duration and end-expired O2 content in bottlenose dolphins (Tursiops truncatus) before and after static surface breath-holds ranging from 34 to 292 s. There was considerable variation in the end-expired O2, V T and f R following a breath-hold. The analysis suggests that the dolphins attempt to minimize recovery following a dive by altering V T and f R to rapidly replenish the O2 stores. For the first breath following a surface breath-hold, the end-expired O2 decreased with dive duration, while V T and f R increased. Throughout the recovery period, end-expired O2 increased while the respiratory effort (V T, f R) decreased. We propose that the dolphins alter respiratory effort following a breath-hold according to the reduction in end-expired O2 levels, allowing almost complete recovery after 1.2 min.
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Affiliation(s)
- Andreas Fahlman
- Departamento de investigación, Fundación Oceanogràfic de la Comunitat Valenciana, Gran Vía Marqués del Turia 19, 46005 Valencia, Spain .,Departamento de Zoología, Grupo de Investigación Biomédica en Imagen GIBI230, Instituto de Investigación Sanitaria La Fe, Av. Fernando Abril Martorell 106, 46026 Valencia, Spain
| | - Micah Brodsky
- Micah Brodsky, V.M.D. Consulting, 1287 NE 96th Street, Miami Shores, FL 33138, USA
| | - Stefan Miedler
- Departamento de investigación, Fundación Oceanogràfic de la Comunitat Valenciana, Gran Vía Marqués del Turia 19, 46005 Valencia, Spain
| | - Sophie Dennison
- TeleVet Imaging Solutions, PLLC, PO BOX 3344, Oakton, VA 22124, USA
| | - Marina Ivančić
- Chicago Zoological Society, 3300 Golf Road, Brookfield, IL 60513, USA
| | - Gregg Levine
- Dolphin Quest, Oahu, 5000 Kahala Ave, Honolulu, HI 96816, USA
| | | | - Mercy Manley
- Siegfried & Roy's Secret Garden and Dolphin Habitat, The Mirage, Las Vegas, NV 89109, USA
| | - Joan Rocabert
- Mellow Design, C/ Bany dels pavesos 3, 46001 Valencia, Spain
| | - Alicia Borque-Espinosa
- Departamento de investigación, Fundación Oceanogràfic de la Comunitat Valenciana, Gran Vía Marqués del Turia 19, 46005 Valencia, Spain.,Departamento de Zoología, Grupo de Investigación Biomédica en Imagen GIBI230, Instituto de Investigación Sanitaria La Fe, Av. Fernando Abril Martorell 106, 46026 Valencia, Spain.,Universidad de Valencia, Av. de Blasco Ibáñez, 13, 46010 Valencia, Spain
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9
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Garcia Párraga D, Moore M, Fahlman A. Pulmonary ventilation-perfusion mismatch: a novel hypothesis for how diving vertebrates may avoid the bends. Proc Biol Sci 2018; 285:20180482. [PMID: 29695441 PMCID: PMC5936736 DOI: 10.1098/rspb.2018.0482] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2018] [Accepted: 03/28/2018] [Indexed: 11/22/2022] Open
Abstract
Hydrostatic lung compression in diving marine mammals, with collapsing alveoli blocking gas exchange at depth, has been the main theoretical basis for limiting N2 uptake and avoiding gas emboli (GE) as they ascend. However, studies of beached and bycaught cetaceans and sea turtles imply that air-breathing marine vertebrates may, under unusual circumstances, develop GE that result in decompression sickness (DCS) symptoms. Theoretical modelling of tissue and blood gas dynamics of breath-hold divers suggests that changes in perfusion and blood flow distribution may also play a significant role. The results from the modelling work suggest that our current understanding of diving physiology in many species is poor, as the models predict blood and tissue N2 levels that would result in severe DCS symptoms (chokes, paralysis and death) in a large fraction of natural dive profiles. In this review, we combine published results from marine mammals and turtles to propose alternative mechanisms for how marine vertebrates control gas exchange in the lung, through management of the pulmonary distribution of alveolar ventilation ([Formula: see text]) and cardiac output/lung perfusion ([Formula: see text]), varying the level of [Formula: see text] in different regions of the lung. Man-made disturbances, causing stress, could alter the [Formula: see text] mismatch level in the lung, resulting in an abnormally elevated uptake of N2, increasing the risk for GE. Our hypothesis provides avenues for new areas of research, offers an explanation for how sonar exposure may alter physiology causing GE and provides a new mechanism for how air-breathing marine vertebrates usually avoid the diving-related problems observed in human divers.
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Affiliation(s)
| | - Michael Moore
- Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA
| | - Andreas Fahlman
- Fundación Oceanogràfic, Ciudad de las Artes y las Ciencias, 46013 Valencia, Spain
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10
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Lewden A, Enstipp MR, Picard B, van Walsum T, Handrich Y. High peripheral temperatures in king penguins while resting at sea: thermoregulation versus fat deposition. ACTA ACUST UNITED AC 2017. [PMID: 28623225 DOI: 10.1242/jeb.158980] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Marine endotherms living in cold water face an energetically challenging situation. Unless properly insulated, these animals will lose heat rapidly. The field metabolic rate of king penguins at sea is about twice that on land. However, when at sea, their metabolic rate is higher during extended resting periods at the surface than during foraging, when birds descend to great depth in pursuit of their prey. This is most likely explained by differences in thermal status. During foraging, peripheral vasoconstriction leads to a hypothermic shell, which is rewarmed during extended resting bouts at the surface. Maintaining peripheral perfusion during rest in cold water, however, will greatly increase heat loss and, therefore, thermoregulatory costs. Two hypotheses have been proposed to explain the maintenance of a normothermic shell during surface rest: (1) to help the unloading of N2 accumulated during diving; and (2) to allow the storage of fat in subcutaneous tissue, following the digestion of food. We tested the latter hypothesis by maintaining king penguins within a shallow seawater tank, while we recorded tissue temperature at four distinct sites. When king penguins were released into the tank during the day, their body temperature immediately declined. However, during the night, periodic rewarming of abdominal and peripheral tissues occurred, mimicking temperature patterns observed in the wild. Body temperatures, particularly in the flank, also depended on body condition and were higher in 'lean' birds (after 10 days of fasting) than in 'fat' birds. While not explicitly tested, our observation that nocturnal rewarming persists in the absence of diving activity during the day does not support the N2 unloading hypothesis. Rather, differences in temperature changes throughout the day and night, and the effect of body condition/mass supports the hypothesis that tissue perfusion during rest is required for nutritional needs.
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Affiliation(s)
- Agnès Lewden
- Université de Strasbourg, CNRS, Département Ecologie, Physiologie et Ethologie, IPHC UMR 7178, F-67000 Strasbourg, France
| | - Manfred R Enstipp
- Université de Strasbourg, CNRS, Département Ecologie, Physiologie et Ethologie, IPHC UMR 7178, F-67000 Strasbourg, France.,Centre d'Etudes Biologiques de Chizé, CNRS, UMR 7372, 79360 Villiers en Bois, France
| | - Baptiste Picard
- Centre d'Etudes Biologiques de Chizé, CNRS, UMR 7372, 79360 Villiers en Bois, France
| | - Tessa van Walsum
- University of Roehampton, Department of Life Sciences, London SW15 4JD, UK
| | - Yves Handrich
- Université de Strasbourg, CNRS, Département Ecologie, Physiologie et Ethologie, IPHC UMR 7178, F-67000 Strasbourg, France
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11
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Fahlman A, Loring SH, Johnson SP, Haulena M, Trites AW, Fravel VA, Van Bonn WG. Inflation and deflation pressure-volume loops in anesthetized pinnipeds confirms compliant chest and lungs. Front Physiol 2014; 5:433. [PMID: 25426080 PMCID: PMC4226140 DOI: 10.3389/fphys.2014.00433] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2014] [Accepted: 10/22/2014] [Indexed: 11/13/2022] Open
Abstract
We examined structural properties of the marine mammal respiratory system, and tested Scholander's hypothesis that the chest is highly compliant by measuring the mechanical properties of the respiratory system in five species of pinniped under anesthesia (Pacific harbor seal, Phoca vitulina; northern elephant seal, Mirounga angustirostris; northern fur seal Callorhinus ursinus; California sea lion, Zalophus californianus; and Steller sea lion, Eumetopias jubatus). We found that the chest wall compliance (CCW) of all five species was greater than lung compliance (airways and alveoli, CL) as predicted by Scholander, which suggests that the chest provides little protection against alveolar collapse or lung squeeze. We also found that specific respiratory compliance was significantly greater in wild animals than in animals raised in an aquatic facility. While differences in ages between the two groups may affect this incidental finding, it is also possible that lung conditioning in free-living animals may increase pulmonary compliance and reduce the risk of lung squeeze during diving. Overall, our data indicate that compliance of excised pinniped lungs provide a good estimate of total respiratory compliance.
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Affiliation(s)
- Andreas Fahlman
- Life Sciences, Texas A&M University-Corpus Christi Corpus Christi, TX, USA
| | - Stephen H Loring
- Department of Anesthesia, Critical Care and Pain Medicine, Beth Israel Deaconess Medical Center Boston, MA, USA
| | | | | | - Andrew W Trites
- Marine Mammal Research Unit, Fisheries Centre, University of British Columbia Vancouver, BC, Canada
| | | | - William G Van Bonn
- The Marine Mammal Center Sausalito, CA, USA ; A. Watson Armour III Center for Animal Health and Welfare, Shedd Aquarium Chicago, IL, USA
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12
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Fahlman A, Tyack PL, Miller PJO, Kvadsheim PH. How man-made interference might cause gas bubble emboli in deep diving whales. Front Physiol 2014; 5:13. [PMID: 24478724 PMCID: PMC3904108 DOI: 10.3389/fphys.2014.00013] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2013] [Accepted: 01/07/2014] [Indexed: 11/13/2022] Open
Abstract
Recent cetacean mass strandings in close temporal and spatial association with sonar activity has raised the concern that anthropogenic sound may harm breath-hold diving marine mammals. Necropsy results of the stranded whales have shown evidence of bubbles in the tissues, similar to those in human divers suffering from decompression sickness (DCS). It has been proposed that changes in behavior or physiological responses during diving could increase tissue and blood N2 levels, thereby increasing DCS risk. Dive data recorded from sperm, killer, long-finned pilot, Blainville's beaked and Cuvier's beaked whales before and during exposure to low- (1-2 kHz) and mid- (2-7 kHz) frequency active sonar were used to estimate the changes in blood and tissue N2 tension (PN2 ). Our objectives were to determine if differences in (1) dive behavior or (2) physiological responses to sonar are plausible risk factors for bubble formation. The theoretical estimates indicate that all species may experience high N2 levels. However, unexpectedly, deep diving generally result in higher end-dive PN2 as compared with shallow diving. In this focused review we focus on three possible explanations: (1) We revisit an old hypothesis that CO2, because of its much higher diffusivity, forms bubble precursors that continue to grow in N2 supersaturated tissues. Such a mechanism would be less dependent on the alveolar collapse depth but affected by elevated levels of CO2 following a burst of activity during sonar exposure. (2) During deep dives, a greater duration of time might be spent at depths where gas exchange continues as compared with shallow dives. The resulting elevated levels of N2 in deep diving whales might also make them more susceptible to anthropogenic disturbances. (3) Extended duration of dives even at depths beyond where the alveoli collapse could result in slow continuous accumulation of N2 in the adipose tissues that eventually becomes a liability.
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Affiliation(s)
- Andreas Fahlman
- Department of Life Sciences, Texas A&M University Corpus Christi Corpus Christi, TX, USA
| | - Peter L Tyack
- Sea Mammal Research Unit, University of St. Andrews St. Andrews, UK
| | | | - Petter H Kvadsheim
- Maritime Systems Division, Norwegian Defence Research Establishment (FFI) Horten, Norway
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13
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Hanuise N, Bost CA, Handrich Y. Optimization of transit strategies while diving in foraging king penguins. J Zool (1987) 2013. [DOI: 10.1111/jzo.12026] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- N. Hanuise
- IPHC-DEPE; Université de Strasbourg; Strasbourg France
- UMR7178; CNRS; Strasbourg France
- CEBC - CNRS UPR 1934; Centre d'Études Biologiques de Chizé; Villiers en Bois France
| | - C.-A. Bost
- CEBC - CNRS UPR 1934; Centre d'Études Biologiques de Chizé; Villiers en Bois France
| | - Y. Handrich
- IPHC-DEPE; Université de Strasbourg; Strasbourg France
- UMR7178; CNRS; Strasbourg France
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14
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Kvadsheim PH, Miller PJO, Tyack PL, Sivle LD, Lam FPA, Fahlman A. Estimated Tissue and Blood N(2) Levels and Risk of Decompression Sickness in Deep-, Intermediate-, and Shallow-Diving Toothed Whales during Exposure to Naval Sonar. Front Physiol 2012; 3:125. [PMID: 22590458 PMCID: PMC3349243 DOI: 10.3389/fphys.2012.00125] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2012] [Accepted: 04/14/2012] [Indexed: 11/29/2022] Open
Abstract
Naval sonar has been accused of causing whale stranding by a mechanism which increases formation of tissue N2 gas bubbles. Increased tissue and blood N2 levels, and thereby increased risk of decompression sickness (DCS), is thought to result from changes in behavior or physiological responses during diving. Previous theoretical studies have used hypothetical sonar-induced changes in both behavior and physiology to model blood and tissue N2 tension PN2, but this is the first attempt to estimate the changes during actual behavioral responses to sonar. We used an existing mathematical model to estimate blood and tissue N2 tension PN2 from dive data recorded from sperm, killer, long-finned pilot, Blainville’s beaked, and Cuvier’s beaked whales before and during exposure to Low- (1–2 kHz) and Mid- (2–7 kHz) frequency active sonar. Our objectives were: (1) to determine if differences in dive behavior affects risk of bubble formation, and if (2) behavioral- or (3) physiological responses to sonar are plausible risk factors. Our results suggest that all species have natural high N2 levels, with deep diving generally resulting in higher end-dive PN2 as compared with shallow diving. Sonar exposure caused some changes in dive behavior in both killer whales, pilot whales and beaked whales, but this did not lead to any increased risk of DCS. However, in three of eight exposure session with sperm whales, the animal changed to shallower diving, and in all these cases this seem to result in an increased risk of DCS, although risk was still within the normal risk range of this species. When a hypothetical removal of the normal dive response (bradycardia and peripheral vasoconstriction), was added to the behavioral response during model simulations, this led to an increased variance in the estimated end-dive N2 levels, but no consistent change of risk. In conclusion, we cannot rule out the possibility that a combination of behavioral and physiological responses to sonar have the potential to alter the blood and tissue end-dive N2 tension to levels which could cause DCS and formation of in vivo bubbles, but the actually observed behavioral responses of cetaceans to sonar in our study, do not imply any significantly increased risk of DCS.
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Affiliation(s)
- P H Kvadsheim
- Maritime Systems Division, Norwegian Defence Research Establishment (FFI) Horten, Norway
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15
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Hooker SK, Fahlman A, Moore MJ, de Soto NA, de Quirós YB, Brubakk AO, Costa DP, Costidis AM, Dennison S, Falke KJ, Fernandez A, Ferrigno M, Fitz-Clarke JR, Garner MM, Houser DS, Jepson PD, Ketten DR, Kvadsheim PH, Madsen PT, Pollock NW, Rotstein DS, Rowles TK, Simmons SE, Van Bonn W, Weathersby PK, Weise MJ, Williams TM, Tyack PL. Deadly diving? Physiological and behavioural management of decompression stress in diving mammals. Proc Biol Sci 2012; 279:1041-50. [PMID: 22189402 PMCID: PMC3267154 DOI: 10.1098/rspb.2011.2088] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2011] [Accepted: 11/28/2011] [Indexed: 11/19/2022] Open
Abstract
Decompression sickness (DCS; 'the bends') is a disease associated with gas uptake at pressure. The basic pathology and cause are relatively well known to human divers. Breath-hold diving marine mammals were thought to be relatively immune to DCS owing to multiple anatomical, physiological and behavioural adaptations that reduce nitrogen gas (N(2)) loading during dives. However, recent observations have shown that gas bubbles may form and tissue injury may occur in marine mammals under certain circumstances. Gas kinetic models based on measured time-depth profiles further suggest the potential occurrence of high blood and tissue N(2) tensions. We review evidence for gas-bubble incidence in marine mammal tissues and discuss the theory behind gas loading and bubble formation. We suggest that diving mammals vary their physiological responses according to multiple stressors, and that the perspective on marine mammal diving physiology should change from simply minimizing N(2) loading to management of the N(2) load. This suggests several avenues for further study, ranging from the effects of gas bubbles at molecular, cellular and organ function levels, to comparative studies relating the presence/absence of gas bubbles to diving behaviour. Technological advances in imaging and remote instrumentation are likely to advance this field in coming years.
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Affiliation(s)
- S K Hooker
- Sea Mammal Research Unit, Scottish Oceans Institute, University of St Andrews, Fife, UK.
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16
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Dennison S, Moore MJ, Fahlman A, Moore K, Sharp S, Harry CT, Hoppe J, Niemeyer M, Lentell B, Wells RS. Bubbles in live-stranded dolphins. Proc Biol Sci 2011; 279:1396-404. [PMID: 21993505 PMCID: PMC3282370 DOI: 10.1098/rspb.2011.1754] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Bubbles in supersaturated tissues and blood occur in beaked whales stranded near sonar exercises, and post-mortem in dolphins bycaught at depth and then hauled to the surface. To evaluate live dolphins for bubbles, liver, kidneys, eyes and blubber-muscle interface of live-stranded and capture-release dolphins were scanned with B-mode ultrasound. Gas was identified in kidneys of 21 of 22 live-stranded dolphins and in the hepatic portal vasculature of 2 of 22. Nine then died or were euthanized and bubble presence corroborated by computer tomography and necropsy, 13 were released of which all but two did not re-strand. Bubbles were not detected in 20 live wild dolphins examined during health assessments in shallow water. Off-gassing of supersaturated blood and tissues was the most probable origin for the gas bubbles. In contrast to marine mammals repeatedly diving in the wild, stranded animals are unable to recompress by diving, and thus may retain bubbles. Since the majority of beached dolphins released did not re-strand it also suggests that minor bubble formation is tolerated and will not lead to clinically significant decompression sickness.
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Affiliation(s)
- S Dennison
- Department of Biology, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA
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18
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Lemaitre F, Fahlman A, Gardette B, Kohshi K. Decompression sickness in breath-hold divers: A review. J Sports Sci 2009; 27:1519-34. [DOI: 10.1080/02640410903121351] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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19
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Could beaked whales get the bends? Respir Physiol Neurobiol 2009; 167:235-46. [DOI: 10.1016/j.resp.2009.04.023] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2009] [Revised: 04/28/2009] [Accepted: 04/30/2009] [Indexed: 11/23/2022]
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Fahlman A, Hooker SK, Olszowka A, Bostrom BL, Jones DR. Estimating the effect of lung collapse and pulmonary shunt on gas exchange during breath-hold diving: the Scholander and Kooyman legacy. Respir Physiol Neurobiol 2008; 165:28-39. [PMID: 18973832 DOI: 10.1016/j.resp.2008.09.013] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2008] [Revised: 09/25/2008] [Accepted: 09/26/2008] [Indexed: 10/21/2022]
Abstract
We developed a mathematical model to investigate the effect of lung compression and collapse (pulmonary shunt) on the uptake and removal of O(2), CO(2) and N(2) in blood and tissue of breath-hold diving mammals. We investigated the consequences of pressure (diving depth) and respiratory volume on pulmonary shunt and gas exchange as pressure compressed the alveoli. The model showed good agreement with previous studies of measured arterial O(2) tensions (Pa(O)(2)) from freely diving Weddell seals and measured arterial and venous N(2) tensions from captive elephant seals compressed in a hyperbaric chamber. Pulmonary compression resulted in a rapid spike in Pa(O)(2) and arterial CO(2) tension, followed by cyclical variation with a periodicity determined by Q(tot). The model showed that changes in diving lung volume are an efficient behavioural means to adjust the extent of gas exchange with depth. Differing models of lung compression and collapse depth caused major differences in blood and tissue N(2) estimates. Our integrated modelling approach contradicted predictions from simple models, and emphasised the complex nature of physiological interactions between circulation, lung compression and gas exchange. Overall, our work suggests the need for caution in interpretation of previous model results based on assumed collapse depths and all-or-nothing lung collapse models.
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Affiliation(s)
- A Fahlman
- Global Diving Research, Ottawa, ON, Canada K2J 5E8.
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