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 T.; Nichols, Cassandra; Lanyon, Janet M.

doi:10.1007/s00227-014-2428-4

Cited by 18 publications

(9 citation statements)

References 46 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…While skin appendages (hair follicles, sebaceous glands, and sweat glands) are associated with the epidermis, they project deep into the dermal layer and are absent (sweat glands) or sparsely distributed (e.g., vibrissae, specialized tactile hairs scattered over the body) in sirenians 43 . Consistent with previous reports [43][44][45][46] , we observed a thin epidermis and a thick dermis in the dugong (Figure 4a) and the West Indian manatee (Figure S4). We identified and validated using dugong epidermis RNA-seq reads the loss of multiple skin-associated genes (Figure 4b and Table S9).…”

Section: The Integumentary Systemsupporting

confidence: 93%

Sirenian genomes illuminate the evolution of fully aquatic species within the mammalian superorder Afrotheria

Tian,

Zhang,

Kang

et al. 2023

Preprint

Self Cite

View full text Add to dashboard Cite

Sirenians of the diverse superorder Afrotheria were the first mammals to retransition from land to water and are the sole herbivorous marine mammals, but little is known about the underlying genomic changes. Here, we generated a chromosome-level dugong (Dugong dugon) genome. A comparison of our assembly and a recent West Indian manatee genome with other afrotherian genomes revealed possible molecular solutions to aquatic life by sirenians, including a shift in daily activity patterns (circadian clock) and tolerance to a high-iodine plant diet mediated through changes in the iodide transporter NIS (SLC5A5) and its co-transporters. Functional in vitro assays confirmed that sirenian amino acid substitutions alter the properties of the circadian clock protein PER2 and NIS. Sirenians show evidence of convergent regression of integumentary system (skin and its appendages) genes with cetaceans, the only other fully aquatic mammal group. Our analysis also uncovered gene losses that may be maladaptive in a modern environment, including a candidate gene (KCNK18) for sirenian cold stress syndrome likely lost during their evolutionary shift in daily activity patterns. Finally, genomes from nine Australian locations and the functionally extinct Okinawan population confirm and date a genetic break on the Australian east coast and highlight the need for whole-genome resequencing data from small or isolated dugong populations worldwide for conservation and genetic management.

show abstract

Section: The Integumentary Systemsupporting

confidence: 93%

Sirenian genomes illuminate the evolution of fully aquatic species within the mammalian superorder Afrotheria

Tian,

Zhang,

Kang

et al. 2023

Preprint

Self Cite

View full text Add to dashboard Cite

show abstract

“…Ex vivo studies have enhanced our understanding of the role of blubber by investigating the physical (e.g. adipocyte morphology, thickness, thermal conductivity [ 81–85 ]) and biochemical (e.g. lipid content, fatty acid composition, and stratification [ 19 , 76 , 86–88 ]) properties of blubber ( Figure 2 ) .…”

Section: Insights From Ex Vivo and In Vi...mentioning

confidence: 99%

Advances in thermal physiology of diving marine mammals: The dual role of peripheral perfusion

Favilla

Horning²,

Costa

2021

Temperature

View full text Add to dashboard Cite

The ability to maintain a high core body temperature is a defining characteristic of all mammals, yet their diverse habitats present disparate thermal challenges that have led to specialized adaptations. Marine mammals inhabit a highly conductive environment. Their thermoregulatory capabilities far exceed our own despite having limited avenues of heat transfer. Additionally, marine mammals must balance their thermoregulatory demands with those associated with diving (i.e. oxygen conservation), both of which rely on cardiovascular adjustments. This review presents the progress and novel efforts in investigating marine mammal thermoregulation, with a particular focus on the role of peripheral perfusion. Early studies in marine mammal thermal physiology were primarily performed in the laboratory and provided foundational knowledge through in vivo experiments and ex vivo measurements. However, the ecological relevance of these findings remains unknown because comparable efforts on free-ranging animals have been limited. We demonstrate the utility of biologgers for studying their thermal adaptations in the context in which they evolved. Our preliminary results from freely diving northern elephant seals ( Mirounga angustirostris ) reveal blubber’s dynamic nature and the complex interaction between thermoregulation and the dive response due to the dual role of peripheral perfusion. Further exploring the potential use of biologgers for measuring physiological variables relevant to thermal physiology in other marine mammal species will enhance our understanding of the relative importance of morphology, physiology, and behavior for thermoregulation and overall homeostasis.

show abstract

“…A fundamental property of insulation is its thermal conductivity, which has been determined for blubber and fur from sculp samples of various species (Figure 6; Kvadsheim et al, 1994Kvadsheim et al, , 1996Dunkin et al, 2005;Bagge et al, 2012;Liwanag et al, 2012a,b;Horgan et al, 2014). These studies provided a single, species-specific value for thermal conductivity, as is appropriate for ex vivo measurements.…”

Section: Quantifying Dynamic Properties Of Insulationmentioning

confidence: 99%

Thermoregulatory Strategies of Diving Air-Breathing Marine Vertebrates: A Review

Favilla

Costa

2020

Front. Ecol. Evol.

View full text Add to dashboard Cite

The aquatic habitat of marine "air-breathing" vertebrates provides a significant thermoregulatory challenge due to the high thermal conductivity of water. In addition to temperature changes across their range, air-breathing vertebrates experience temperature changes on the timescale of seconds to minutes as they perform dives to access two critical resources: air at the surface and food at depth. In response to these challenges, air-breathing vertebrates have developed morphological and physiological adaptations that align with their life histories and phylogenies and contribute to homeostasis. However, the physiological and behavioral mechanisms used to maintain thermal balance while diving is still poorly understood. The cardiovascular system is integral to the physiological responses associated with the dive response, exercise, digestion, and thermoregulation. The adjustments required to meet one physiological demand may not be compatible with another and can result in a potential conflict between the various physiological demands imposed on air-breathing divers. We reviewed the literature on thermoregulation while diving in an effort to synthesize our current understanding of the thermoregulatory strategies of diving air-breathing marine vertebrates. Studies have demonstrated that thermoregulatory strategies can involve the temporal separation of two conflicting responses, a compromise in the performance of one response over another, or coordination of synergistic responses. We hope that a review and synthesis of both laboratory and field studies will stimulate future research efforts at the intersection of thermoregulation and diving physiology. Expanding the use of physiological biologgers, particularly to understudied species, will enhance our understanding of how these animals coordinate various physiological demands to maintain homeostasis in a thermally challenging environment.

show abstract

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

Cited by 18 publications

References 46 publications

Sirenian genomes illuminate the evolution of fully aquatic species within the mammalian superorder Afrotheria

Sirenian genomes illuminate the evolution of fully aquatic species within the mammalian superorder Afrotheria

Advances in thermal physiology of diving marine mammals: The dual role of peripheral perfusion

Thermoregulatory Strategies of Diving Air-Breathing Marine Vertebrates: A Review

Contact Info

Product

Resources

About