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H 1 Size matters for balancing energy supply and demand in aquatic ectotherms

Auteurs : Verberk, Wilco C.E.P. (Auteur de la Conférence)
CIRM (Editeur )

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    Résumé : Oxygen is essential for burning food and generate energy, but may become limiting for aquatic organisms that rely on gas exchange under water. This is because breathing under water is challenging: the diffusion of oxygen is orders of magnitude lower in water than in air, while the higher density and viscosity of water greatly enhance the cost of breathing. Given that oxygen may be also be a limiting resource, respiration physiology may be relevant to understand energy budgets in aquatic ectotherms.
    Traditionally, respiration physiology has focused on the benefits of extracting sufficient amounts of oxygen and thus prevent asphyxiation. However, breathing oxygen is intrinsically dangerous: while a shortage of oxygen quickly leads to asphyxiation, too much oxygen is toxic. Therefore, the ability to regulate oxygen consumption rates (i.e. respiratory control) is at a premium; good respiratory control will enable ectotherms to balance oxygen toxicity against the risk of asphyxiation across a wide range of temperatures.
    In this presentation I will focus on the effects of body size and temperature on this balancing act with regard to oxygen uptake and consumption. Body size is intimately tied to oxygen budgets and hence energy budgets through size related changes in oxygen requirements and respiratory surfaces. Furthermore, a larger body size may represent a respiratory advantage that helps to overcome viscosity. Given that viscous forces are larger in cold water, this respiratory advantage represents a novel explanation for the pattern of larger body sizes in cold water, with polar gigantism as the extreme manifestation.
    Temperature is also intimately tied to oxygen budgets and hence energy budgets through thermal controls on metabolism and temperature related changes in the availability of dissolved oxygen (notably diffusivity, viscosity and solubility). Thus, differences in temperatures may act more strongly on ectotherms that rely on aquatic rather than on aerial gas exchange. Comparing four different insect orders, I demonstrate that thermal tolerance is indeed affected more by the prevalent oxygen conditions in species with poor respiration control. In conclusion, the ability to regulate gas exchange (i.e. respiratory control) is thus a key attribute of species that helps to explain thermal responses from an oxygen perspective.

    Codes MSC :
    92C15 - Developmental biology, pattern formation
    92C30 - Physiology (general)
    92D25 - Population dynamics (general)
    92D50 - Animal behavior

      Informations sur la Vidéo

      Langue : Anglais
      Date de publication : 13/05/15
      Date de captation : 29/04/15
      Collection : Research talks ; Dynamical Systems and Ordinary Differential Equations ; Mathematics in Science and Technology
      Format : quicktime ; audio/x-aac
      Durée : 00:54:34
      Domaine : Dynamical Systems & ODE ; Mathematics in Science & Technology
      Audience : Chercheurs ; Doctorants , Post - Doctorants
      Download : https://videos.cirm-math.fr/2015-04-29_Verberk.mp4

    Informations sur la rencontre

    Nom de la rencontre : Modeling energy budgets in ecology: DEB theory / Modélisation des budgets d'énergie en écologie : la théorie DEB
    Organisateurs de la rencontre : Kooijman, Sebastiaan A.L.M. ; Poggiale, Jean-Christophe
    Dates : 20/04/15 - 30/04/15
    Année de la rencontre : 2015
    URL Congrès : https://deb2015.mio.univ-amu.fr/

    Citation Data

    DOI : 10.24350/CIRM.V.18754203
    Cite this video as: Verberk, Wilco C.E.P. (2015). Size matters for balancing energy supply and demand in aquatic ectotherms. CIRM. Audiovisual resource. doi:10.24350/CIRM.V.18754203
    URI : http://dx.doi.org/10.24350/CIRM.V.18754203


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