Adaptations to deep and prolonged diving in phocid seals

  title={Adaptations to deep and prolonged diving in phocid seals},
  author={Arnoldus Schytte Blix},
  journal={Journal of Experimental Biology},
  • A. S. Blix
  • Published 2018
  • Psychology, Medicine
  • Journal of Experimental Biology
ABSTRACT This Review focuses on the original papers that have made a difference to our thinking and were first in describing an adaptation to diving, and less on those that later repeated the findings with better equipment. It describes some important anatomical peculiarities of phocid seals, as well as their many physiological responses to diving. In so doing, it is argued that the persistent discussions on the relevance and differences between responses seen in forced dives in the laboratory… Expand
State of the art review: from the seaside to the bedside: insights from comparative diving physiology into respiratory, sleep and critical care
This review highlights past and recent progress in the field of comparative diving physiology with emphasis on its potential relevance to human medicine. Expand
Respiratory sinus arrhythmia and submersion bradycardia in bottlenose dolphins (Tursiops truncatus)
The results demonstrate that the fH patterns observed during submerged breath-holds are similar to those resulting from RSA during an extended IBI, highlighting the importance of RSA in influencing fH variability and emphasize the need to understand its relationship to submersion bradycardia. Expand
Low guanylyl cyclase activity in Weddell seals: implications for peripheral vasoconstriction and perfusion of the brain during diving.
Results of this study suggest that alterations in the NO-cGMP pathway facilitate the diving response, which is consistent with the priority of cerebral perfusion during diving. Expand
What determines systemic blood flow in vertebrates?
To understand how systemic blood flow (or ‘cardiac output’) is regulated, it is necessary to look at factors beyond the heart, namely vascular capacitance and conductance. Expand
Natural Tolerance to Ischemia and Hypoxemia in Diving Mammals: A Review
The current knowledge regarding the strategies marine mammals use to suppress inflammation and cope with oxidant generation potentially derived from diving-induced ischemia/reperfusion are reviewed. Expand
Smooth Muscle in Cardiac Chambers is Common in Turtles and Extensive in the Emydid Turtle, Trachemys scripta
It is demonstrated that cardiac smooth muscle likely appeared early in turtle evolution and has become extensive within the Emydidae family, possibly in association with diving across other tetrapod clades, while atrial smooth muscle might not associate with diving. Expand
Term placenta of the southern elephant seal (Mirounga leonina).
The placenta of Mirounga leonina, a phocid pinniped, is described, focusing on some morphological features related to fetal nutrition, which might allow substantial endocytosis of detritus even in term placentas, in this species giving birth to precocious offspring. Expand
Contraction of atrial smooth muscle reduces cardiac output in perfused turtle hearts
Evidence is provided that contraction of the smooth muscle in the atria may be able to change cardiac output in turtle hearts and suggests that atrial smooth muscle provides a unique mechanism to control cardiac filling that could be involved in the regulation of stroke volume during diving. Expand
Transcriptome analysis reveals a high aerobic capacity in the whale brain.
A high oxidative capacity in the whale brain is indicated that might help to maintain aerobic metabolism in periods of reduced oxygen availability during dives, and transcripts related to the detoxification of reactive oxygen species were more highly expressed in the visual cortex of whales. Expand
Diving deep: Understanding the genetic components of hypoxia tolerance in marine mammals.
  • A. Hindle
  • Medicine, Biology
  • Journal of applied physiology
  • 2020
Given the inherent logistical and regulatory difficulties associated with functional genetic experiments in marine mammals, several avenues of further investigation are suggested to enable validation of candidate genes for hypoxia tolerance: leveraging phylogeny to better understand convergent phenotypes; ontogenic studies to identify regulation of key genes underlying the elite, adult, Hypoxia-tolerant physiology; and cell culture manipulations to understand gene function. Expand


Cerebral tolerance to asphyxial hypoxia in the harbor seal.
It is concluded that during prolonged apneic asphyxia the seal's brain, unlike that of terrestrial mammals, tolerates a definite period of vO2 reduction prior to the onset of gross functional impairment. Expand
Physiology of diving of birds and mammals.
This review concentrates on the physiological responses, and their control, in freely diving birds and mammals that enable them to remain submerged and sometimes quite active for extended periods ofExpand
Aerobic diving limits of immature Weddell seals
The peak post-dive blood LA concentration relative to dive duration demonstrate that there is a positive relationship between aerobic dive limit (ADL) and body size, and the calculation of the ADL from available oxygen stores correlates well with the lactate/endurance curve intercept. Expand
Techniques used in measuring diving capacities of Weddell Seals
During the austral summer of 1963–64 an investigation was started near “Mc-Murdo” on the diving habits of the Weddell Seal (Leptonychotes weddelli) . The Weddell Seal was selected for thisExpand
Inhibition of shivering in hypothermic seals during diving.
It is concluded that shivering is inhibited during diving to allow a decrease in body temperature whereby oxygen consumption is decreased and diving capacity is extended. Expand
Adaptations to diving in the harbor seal: cardiac output during diving.
These studies suggest that the primary diving adaptation consists of arterial constriction, and with loss of blood flow to peripheral tissues, there is preservation of available O2 and substrate for brain oxygen-dependent metabolism. Expand
Hormonal regulatory adjustments during voluntary diving in Weddell seals.
Monitoring of Weddell seals led to the hypothesis of important adrenergic regulation of the diving response in seals, with rapid reversal at the end of diving and during recovery being regulated by nitroxidergic mechanisms. Expand
Respiratory function and mechanics in pinnipeds and cetaceans
Improved understanding of respiratory physiology under these conditions will be better able to define the physiological constraints imposed on these animals, and how these limitations may affect the survival of marine mammals in a changing environment. Expand
Aerobic and anaerobic metabolism during voluntary diving in Weddell seals: Evidence of preferred pathways from blood chemsitry and behavior
Post-dive arterial lactic acid concentrations were at no time different from resting levels unless the previous dive exceeded 20 to 25 min, while blood gases were in the normal mammalian range, but based upon resting apneic values may drop to remarkably low levels during prolonged dives. Expand
Heart rates in freely diving Weddell Seals, Leptonychotes weddelli.
There appears to be an inverse relationship between heart rate and length of the dive, and this relationship as well as other observed behavioral events that seems to be correlated with heart rate indicate that the seals anticipate the nature of the Dive. Expand