Insulative capacity of the integument of the dugong (Dugong dugon): Thermal conductivity, conductance and resistance measured by in vitro heat flux

Horgan, Patrick, Booth, David, Nichols, Cassandra and Lanyon, Janet M. (2014) Insulative capacity of the integument of the dugong (Dugong dugon): Thermal conductivity, conductance and resistance measured by in vitro heat flux. Marine Biology, 161 6: 1395-1407. doi:10.1007/s00227-014-2428-4


Author Horgan, Patrick
Booth, David
Nichols, Cassandra
Lanyon, Janet M.
Title Insulative capacity of the integument of the dugong (Dugong dugon): Thermal conductivity, conductance and resistance measured by in vitro heat flux
Journal name Marine Biology   Check publisher's open access policy
ISSN 0025-3162
1432-1793
Publication date 2014
Year available 2014
Sub-type Article (original research)
DOI 10.1007/s00227-014-2428-4
Open Access Status Not Open Access
Volume 161
Issue 6
Start page 1395
End page 1407
Total pages 13
Place of publication Heidelberg, Germany
Publisher Springer Verlag
Collection year 2015
Language eng
Subject 1104 Complementary and Alternative Medicine
1105 Dentistry
2303 Ecology
Abstract Extant sirenians are restricted to warm waters, presumably due to their low metabolism and poor thermoregulatory capacity, including thin blubber. When subjected to winter waters, Florida manatees (Trichechus manatus latirostris) migrate to warm areas, but dugongs (Dugong dugon) do not and instead live year-round in winter waters as cool as 15-18 °C. Dugongs appear to be more active than manatees and may have higher metabolic rates, but little is known about thermal energetics or the insulative properties of their integument. This study investigated the physical and thermal properties of whole samples of dugong integument, i.e. epidermis, dermis and hypodermis (blubber) sampled from fresh dugong carcasses collected from 2004 to 2012 in Moreton Bay (27.21°S, 153.25°E). Physico-chemical properties (thickness, density and lipid content) of each component tissue layer were measured. Thermal conductance (C) and conductivity (k) were measured for each tissue layer through in vitro temperature flux experiments within an insulated chamber. C and k were higher for dermis (25.7 ± 1.2 W m-2 K-1, 0.43 ± 0.02 W m-1 K-1, respectively, n = 21) than blubber (24.3 ± 2.4 W m-2 K-1, 0.31 ± 0.01 W m-1 K-1, n = 21), suggesting that blubber, with higher density and lipid content, affords better insulation. However, because the dermis contributes 65 % of integumentary thickness, both layers contribute significantly to insulation. The integument of dugongs is a poorer insulator compared to many cold-water marine mammals, but the greater thickness of its dermal layer means that despite its relatively thin blubber, its integumentary insulation is similar to warm-water dolphins of similar body size.
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: Official 2015 Collection
School of Biological Sciences Publications
 
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