Lipid class and depth-specific thermal properties in the blubber of two species of odontocete cetaceans, the short-finned pilot whale (Globicephala macrorhynchus) and the pygmy sperm whale (Kogia breviceps)
Blubber, the specialized hypodermis of cetaceans, provides thermal insulation through the quantity and quality of lipids it contains. Quality refers to % lipid content; however, not all lipids are the same. Certain deep-diving cetacean groups possess blubber with lipids - wax esters (WE) - that are...
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fthighwire:oai:open-archive.highwire.org:jexbio:jeb.071530v1 2023-05-15T18:26:51+02:00 Lipid class and depth-specific thermal properties in the blubber of two species of odontocete cetaceans, the short-finned pilot whale (Globicephala macrorhynchus) and the pygmy sperm whale (Kogia breviceps) Bagge, Laura E. Koopman, Heather N. Rommel, Sentiel A. McLellan, William A. Pabst, D. A. 2012-09-12 06:38:06.0 text/html http://jeb.biologists.org/cgi/content/short/jeb.071530v1 https://doi.org/10.1242/jeb.071530 en eng Company of Biologists http://jeb.biologists.org/cgi/content/short/jeb.071530v1 http://dx.doi.org/10.1242/jeb.071530 Copyright (C) 2012, Company of Biologists Research Article TEXT 2012 fthighwire https://doi.org/10.1242/jeb.071530 2015-02-28T14:04:22Z Blubber, the specialized hypodermis of cetaceans, provides thermal insulation through the quantity and quality of lipids it contains. Quality refers to % lipid content; however, not all lipids are the same. Certain deep-diving cetacean groups possess blubber with lipids - wax esters (WE) - that are not typically found in mammals, and the insulative quality of “waxy” blubber is unknown. Our study explored the influence of lipid storage class – specifically WE in pygmy sperm whales ( Kogia breviceps n=7) and typical mammalian triacylglycerols (TAG) in short-finned pilot whales ( Globicephala macrorhynchus n=7) – on blubber’s thermal properties. Although the blubber of both species had similar total lipid contents, the thermal conductivity of G. macrorhynchus blubber (0.20 ± 0.01 Wm-1°C-1) was significantly higher than that of K. breviceps (0.15 ± 0.01 Wm-1°C-1; P=0.0006). These results suggest that lipid class significantly influences blubber’s ability to resist heat flow. In addition, because blubber’s lipid content is known to be stratified, we measured its depth-specific thermal conductivities. In K. breviceps blubber, the depth-specific conductivity values tended to vary inversely with lipid content. In contrast, G. macrorhynchus blubber displayed unexpected depth-specific relationships between lipid content and conductivity, which suggests that temperature-dependent effects, such as melting, may be occurring. Differences in heat flux measurements across the depth of the blubber samples provide evidence that both species are capable of storing heat in their blubber. The function of blubber as an insulator is complex and may rely upon its lipid class, stratified composition, and dynamic heat storage capabilities. Text Sperm whale HighWire Press (Stanford University) Journal of Experimental Biology |
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Research Article |
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Research Article Bagge, Laura E. Koopman, Heather N. Rommel, Sentiel A. McLellan, William A. Pabst, D. A. Lipid class and depth-specific thermal properties in the blubber of two species of odontocete cetaceans, the short-finned pilot whale (Globicephala macrorhynchus) and the pygmy sperm whale (Kogia breviceps) |
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Research Article |
description |
Blubber, the specialized hypodermis of cetaceans, provides thermal insulation through the quantity and quality of lipids it contains. Quality refers to % lipid content; however, not all lipids are the same. Certain deep-diving cetacean groups possess blubber with lipids - wax esters (WE) - that are not typically found in mammals, and the insulative quality of “waxy” blubber is unknown. Our study explored the influence of lipid storage class – specifically WE in pygmy sperm whales ( Kogia breviceps n=7) and typical mammalian triacylglycerols (TAG) in short-finned pilot whales ( Globicephala macrorhynchus n=7) – on blubber’s thermal properties. Although the blubber of both species had similar total lipid contents, the thermal conductivity of G. macrorhynchus blubber (0.20 ± 0.01 Wm-1°C-1) was significantly higher than that of K. breviceps (0.15 ± 0.01 Wm-1°C-1; P=0.0006). These results suggest that lipid class significantly influences blubber’s ability to resist heat flow. In addition, because blubber’s lipid content is known to be stratified, we measured its depth-specific thermal conductivities. In K. breviceps blubber, the depth-specific conductivity values tended to vary inversely with lipid content. In contrast, G. macrorhynchus blubber displayed unexpected depth-specific relationships between lipid content and conductivity, which suggests that temperature-dependent effects, such as melting, may be occurring. Differences in heat flux measurements across the depth of the blubber samples provide evidence that both species are capable of storing heat in their blubber. The function of blubber as an insulator is complex and may rely upon its lipid class, stratified composition, and dynamic heat storage capabilities. |
format |
Text |
author |
Bagge, Laura E. Koopman, Heather N. Rommel, Sentiel A. McLellan, William A. Pabst, D. A. |
author_facet |
Bagge, Laura E. Koopman, Heather N. Rommel, Sentiel A. McLellan, William A. Pabst, D. A. |
author_sort |
Bagge, Laura E. |
title |
Lipid class and depth-specific thermal properties in the blubber of two species of odontocete cetaceans, the short-finned pilot whale (Globicephala macrorhynchus) and the pygmy sperm whale (Kogia breviceps) |
title_short |
Lipid class and depth-specific thermal properties in the blubber of two species of odontocete cetaceans, the short-finned pilot whale (Globicephala macrorhynchus) and the pygmy sperm whale (Kogia breviceps) |
title_full |
Lipid class and depth-specific thermal properties in the blubber of two species of odontocete cetaceans, the short-finned pilot whale (Globicephala macrorhynchus) and the pygmy sperm whale (Kogia breviceps) |
title_fullStr |
Lipid class and depth-specific thermal properties in the blubber of two species of odontocete cetaceans, the short-finned pilot whale (Globicephala macrorhynchus) and the pygmy sperm whale (Kogia breviceps) |
title_full_unstemmed |
Lipid class and depth-specific thermal properties in the blubber of two species of odontocete cetaceans, the short-finned pilot whale (Globicephala macrorhynchus) and the pygmy sperm whale (Kogia breviceps) |
title_sort |
lipid class and depth-specific thermal properties in the blubber of two species of odontocete cetaceans, the short-finned pilot whale (globicephala macrorhynchus) and the pygmy sperm whale (kogia breviceps) |
publisher |
Company of Biologists |
publishDate |
2012 |
url |
http://jeb.biologists.org/cgi/content/short/jeb.071530v1 https://doi.org/10.1242/jeb.071530 |
genre |
Sperm whale |
genre_facet |
Sperm whale |
op_relation |
http://jeb.biologists.org/cgi/content/short/jeb.071530v1 http://dx.doi.org/10.1242/jeb.071530 |
op_rights |
Copyright (C) 2012, Company of Biologists |
op_doi |
https://doi.org/10.1242/jeb.071530 |
container_title |
Journal of Experimental Biology |
_version_ |
1766208824387043328 |