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

   https://doi.org/10.1080/23328940.2021.1988817  

   Favilla, Arina B.; Horning, Markus; Costa, Daniel P. (October 2021, Temperature)

   null (Ed.)

   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. 

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2. State of the art review: from the seaside to the bedside: insights from comparative diving physiology into respiratory, sleep and critical care

   https://doi.org/10.1136/thoraxjnl-2018-212136  

   Ponganis, Paul J (April 2019, Thorax)

   Anatomical and physiological adaptations of animals to extreme environments provide insight into basic physiological principles and potential therapies for human disease. In that regard, the diving physiology of marine mammals and seabirds is especially relevant to pulmonary and cardiovascular function, and to the pathology and potential treatment of patients with hypoxaemia and/or ischaemia. This review highlights past and recent progress in the field of comparative diving physiology with emphasis on its potential relevance to human medicine. 

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3. Diving physiology of marine mammals and birds: the development of biologging techniques

   https://doi.org/10.1098/rstb.2020.0211  

   Williams, Cassondra L.; Ponganis, Paul J. (August 2021, Philosophical Transactions of the Royal Society B: Biological Sciences)

   null (Ed.)

   In the 1940s, Scholander and Irving revealed fundamental physiological responses to forced diving of marine mammals and birds, setting the stage for the study of diving physiology. Since then, diving physiology research has moved from the laboratory to the field. Modern biologging, with the development of microprocessor technology, recorder memory capacity and battery life, has advanced and expanded investigations of the diving physiology of marine mammals and birds. This review describes a brief history of the start of field diving physiology investigations, including the invention of the time depth recorder, and then tracks the use of biologging studies in four key diving physiology topics: heart rate, blood flow, body temperature and oxygen store management. Investigations of diving heart rates in cetaceans and O 2 store management in diving emperor penguins are highlighted to emphasize the value of diving physiology biologging research. The review concludes with current challenges, remaining diving physiology questions and what technologies are needed to advance the field. This article is part of the theme issue ‘Measuring physiology in free-living animals (Part I)’. 

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4. Life in the Midwater: The Ecology of Deep Pelagic Animals

   https://doi.org/10.1146/annurev-marine-031623-095435  

   Haddock, Steven HD; Choy, C Anela (January 2024, Annual Review of Marine Science)

   The water column of the deep ocean is dark, cold, low in food, and under crushing pressures, yet it is full of diverse life. Due to its enormous volume, this mesopelagic zone is home to some of the most abundant animals on the planet. Rather than struggling to survive, they thrive—owing to a broad set of adaptations for feeding, behavior, and physiology. Our understanding of these adaptations is constrained by the tools available for exploring the deep sea, but this tool kit is expanding along with technological advances. Each time we apply a new method to the depths, we gain surprising insights about genetics, ecology, behavior, physiology, diversity, and the dynamics of change. These discoveries show structure within the seemingly uniform habitat, limits to the seemingly inexhaustible resources, and vulnerability in the seemingly impervious environment. To understand midwater ecology, we need to reimagine the rules that govern terrestrial ecosystems. By spending more time at depth—with whatever tools are available—we can fill the knowledge gaps and better link ecology to the environment throughout the water column. 

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5. Herpetofaunal ecology (often) makes sense in the light of thermal physiology

   Claunch, NM; Goodman, CM; Guralnick RP; Barve, N; Kluever, B. Longo; Reed, RN; Taylor, EN; Romagosa, CM (July 2022, The 55th Scientific Meeting of Australian Society of Herpetologists)

   An underlying rule in biology is that temperature affects physiological processes. This is salient in ectothermic organisms such as herpetofauna, which must cope with the challenges of changing body temperatures. The limitations associated with living in a dynamic thermal environment often translate into patterns of herpetofaunal distribution and behavior. As such, an understanding of thermal physiology and thermal environment are foundational to studies of herpetofauna. Beginning with a brief review of the contributions of Hal Heatwole and Hal Cogger to the field of thermal ecology, I explore how some methodologies and have changed over time with technological improvements to tackle emergent issues including invasion by herpetofauna and understanding of disease processes. I discuss recent applications of thermal ecology in my own research to understand and predict distribution of invasive herpetofauna, and to understand disease processes in wild populations. Specifically, I discuss the predictive value of critical thermal minima on current and future distributions of invasive lizards introduced to Florida, USA (Leiocephalus carinatus and Furcifer pardalis), obtained through different experimental and computational methods. I also discuss planned methodologies to assess the role of thermoregulation in combatting infection of Batrachochytrium dendrobatidis and B. salamandrivorans in plethodontid salamanders. 

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