The Nasal Geometry of the Reindeer Gives Energy-Efficient Respiration
Abstract Reindeer in the arctic region live under very harsh conditions and may face temperatures below 233 K. Therefore, efficient conservation of body heat and water is important for their survival. Alongside their insulating fur, the reindeer nasal mechanism for heat and mass exchange during resp...
Published in: | Journal of Non-Equilibrium Thermodynamics |
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Walter de Gruyter GmbH
2017
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crdegruyter:10.1515/jnet-2016-0038 2024-05-19T07:36:02+00:00 The Nasal Geometry of the Reindeer Gives Energy-Efficient Respiration Magnanelli, Elisa Wilhelmsen, Øivind Acquarone, Mario Folkow, Lars P. Kjelstrup, Signe 2017 http://dx.doi.org/10.1515/jnet-2016-0038 http://www.degruyter.com/view/j/jnet.2017.42.issue-1/jnet-2016-0038/jnet-2016-0038.xml https://www.degruyter.com/document/doi/10.1515/jnet-2016-0038/pdf unknown Walter de Gruyter GmbH Journal of Non-Equilibrium Thermodynamics volume 42, issue 1 ISSN 0340-0204 1437-4358 journal-article 2017 crdegruyter https://doi.org/10.1515/jnet-2016-0038 2024-05-02T06:51:53Z Abstract Reindeer in the arctic region live under very harsh conditions and may face temperatures below 233 K. Therefore, efficient conservation of body heat and water is important for their survival. Alongside their insulating fur, the reindeer nasal mechanism for heat and mass exchange during respiration plays a fundamental role. We present a dynamic model to describe the heat and mass transport that takes place inside the reindeer nose, where we account for the complicated geometrical structure of the subsystems that are part of the nose. The model correctly captures the trend in experimental data for the temperature, heat and water recovery in the reindeer nose during respiration. As a reference case, we model a nose with a simple cylindrical-like geometry, where the total volume and contact area are the same as those determined in the reindeer nose. A comparison of the reindeer nose with the reference case shows that the nose geometry has a large influence on the velocity, temperature and water content of the air inside the nose. For all investigated cases, we find that the total entropy production during a breathing cycle is lower for the reindeer nose than for the reference case. The same trend is observed for the total energy consumption. The reduction in the total entropy production caused by the complicated geometry is higher (up to -20 %) at more extreme ambient conditions, when energy efficiency is presumably more important for the maintenance of energy balance in the animal. In the literature, a hypothesis has been proposed, which states that the most energy-efficient design of a system is characterized by equipartition of the entropy production. In agreement with this hypothesis, we find that the local entropy production during a breathing cycle is significantly more uniform for the reindeer nose than for the reference case. This suggests that natural selection has favored designs that give uniform entropy production when energy efficiency is an issue. Animals living in the harsh arctic climate, ... Article in Journal/Newspaper Arctic De Gruyter Journal of Non-Equilibrium Thermodynamics 42 1 |
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Abstract Reindeer in the arctic region live under very harsh conditions and may face temperatures below 233 K. Therefore, efficient conservation of body heat and water is important for their survival. Alongside their insulating fur, the reindeer nasal mechanism for heat and mass exchange during respiration plays a fundamental role. We present a dynamic model to describe the heat and mass transport that takes place inside the reindeer nose, where we account for the complicated geometrical structure of the subsystems that are part of the nose. The model correctly captures the trend in experimental data for the temperature, heat and water recovery in the reindeer nose during respiration. As a reference case, we model a nose with a simple cylindrical-like geometry, where the total volume and contact area are the same as those determined in the reindeer nose. A comparison of the reindeer nose with the reference case shows that the nose geometry has a large influence on the velocity, temperature and water content of the air inside the nose. For all investigated cases, we find that the total entropy production during a breathing cycle is lower for the reindeer nose than for the reference case. The same trend is observed for the total energy consumption. The reduction in the total entropy production caused by the complicated geometry is higher (up to -20 %) at more extreme ambient conditions, when energy efficiency is presumably more important for the maintenance of energy balance in the animal. In the literature, a hypothesis has been proposed, which states that the most energy-efficient design of a system is characterized by equipartition of the entropy production. In agreement with this hypothesis, we find that the local entropy production during a breathing cycle is significantly more uniform for the reindeer nose than for the reference case. This suggests that natural selection has favored designs that give uniform entropy production when energy efficiency is an issue. Animals living in the harsh arctic climate, ... |
format |
Article in Journal/Newspaper |
author |
Magnanelli, Elisa Wilhelmsen, Øivind Acquarone, Mario Folkow, Lars P. Kjelstrup, Signe |
spellingShingle |
Magnanelli, Elisa Wilhelmsen, Øivind Acquarone, Mario Folkow, Lars P. Kjelstrup, Signe The Nasal Geometry of the Reindeer Gives Energy-Efficient Respiration |
author_facet |
Magnanelli, Elisa Wilhelmsen, Øivind Acquarone, Mario Folkow, Lars P. Kjelstrup, Signe |
author_sort |
Magnanelli, Elisa |
title |
The Nasal Geometry of the Reindeer Gives Energy-Efficient Respiration |
title_short |
The Nasal Geometry of the Reindeer Gives Energy-Efficient Respiration |
title_full |
The Nasal Geometry of the Reindeer Gives Energy-Efficient Respiration |
title_fullStr |
The Nasal Geometry of the Reindeer Gives Energy-Efficient Respiration |
title_full_unstemmed |
The Nasal Geometry of the Reindeer Gives Energy-Efficient Respiration |
title_sort |
nasal geometry of the reindeer gives energy-efficient respiration |
publisher |
Walter de Gruyter GmbH |
publishDate |
2017 |
url |
http://dx.doi.org/10.1515/jnet-2016-0038 http://www.degruyter.com/view/j/jnet.2017.42.issue-1/jnet-2016-0038/jnet-2016-0038.xml https://www.degruyter.com/document/doi/10.1515/jnet-2016-0038/pdf |
genre |
Arctic |
genre_facet |
Arctic |
op_source |
Journal of Non-Equilibrium Thermodynamics volume 42, issue 1 ISSN 0340-0204 1437-4358 |
op_doi |
https://doi.org/10.1515/jnet-2016-0038 |
container_title |
Journal of Non-Equilibrium Thermodynamics |
container_volume |
42 |
container_issue |
1 |
_version_ |
1799475067199946752 |