Dear MarMamers,
We are pleased to share our new publication titled "Lung function assessment in the Pacific walrus (Odobenus rosmarus divergens) while
resting on land and submerged in water", which is now available in the Journal of Experimental Biology (http://jeb.biologists.org/lookup/doi/10.1242/jeb.227389)
Abstract:
In the present study, we examined lung function in healthy resting adult (born in 2003) Pacific walruses (Odobenus rosmarus divergens) by measuring respiratory flow (
)
using a custom-made pneumotachometer. Three female walruses (670–1025 kg) voluntarily participated in spirometry trials while spontaneously breathing on land (sitting and lying down in sternal recumbency) and floating in water. While sitting, two walruses
performed active respiratory efforts, and one animal participated in lung compliance measurements. For spontaneous breaths,
was lower when walruses were lying down (e.g. expiration: 7.1±1.2 l s−1) as compared with in water (9.9±1.4 l s−1), while tidal volume (VT, 11.5±4.6 l), breath duration (4.6±1.4 s) and respiratory frequency (7.6±2.2 breaths min−1)
remained the same. The measured VT and specific dynamic lung compliance (0.32±0.07 cmH2O−1) for spontaneous breaths were higher than those estimated for similarly sized terrestrial mammals.
VT increased with body mass (allometric mass-exponent=1.29) and ranged from 3% to 43% of the estimated total lung capacity (TLCest) for spontaneous breaths. When normalized for TLCest, the maximal expiratory
(
exp)
was higher than that estimated in phocids, but lower than that reported in cetaceans and the California sea lion.
exp
was maintained over all lung volumes during spontaneous and active respiratory manoeuvres. We conclude that location (water or land) affects lung function in the walrus and should be considered when studying respiratory physiology in semi-aquatic marine mammals.
If you have any question or would like a
pdf copy of the article, please email: ali_bor@hotmail.com
)
using a custom-made pneumotachometer. Three female walruses (670–1025 kg) voluntarily participated in spirometry trials while spontaneously breathing on land (sitting and lying down in sternal recumbency) and floating in water. While sitting, two walruses
performed active respiratory efforts, and one animal participated in lung compliance measurements. For spontaneous breaths,
was lower when walruses were lying down (e.g. expiration: 7.1±1.2 l s−1) as compared with in water (9.9±1.4 l s−1), while tidal volume (VT, 11.5±4.6 l), breath duration (4.6±1.4 s) and respiratory frequency (7.6±2.2 breaths min−1)
remained the same. The measured VT and specific dynamic lung compliance (0.32±0.07 cmH2O−1) for spontaneous breaths were higher than those estimated for similarly sized terrestrial mammals.
VT increased with body mass (allometric mass-exponent=1.29) and ranged from 3% to 43% of the estimated total lung capacity (TLCest) for spontaneous breaths. When normalized for TLCest, the maximal expiratory
(exp)
was higher than that estimated in phocids, but lower than that reported in cetaceans and the California sea lion.
exp
was maintained over all lung volumes during spontaneous and active respiratory manoeuvres. We conclude that location (water or land) affects lung function in the walrus and should be considered when studying respiratory physiology in semi-aquatic marine mammals.Below is a link to access the full manuscript for a limited number of downloads:
Best wishes
A. Borque-Espinosa