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Auteur Lefevre, S.; Bayley, M.; McKenzie, D.J. url  doi
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  Titre Measuring oxygen uptake in fishes with bimodal respiration Type Article scientifique
  Année 2016 Publication Revue Abrégée J Fish Biol  
  Volume 88 Numéro 1 Pages 206-231  
  Mots-Clés intermittent-closed; oxygen consumption; respiratory partitioning; respirometry  
  Résumé Respirometry is a robust method for measurement of oxygen uptake as a proxy for metabolic rate in fishes, and how species with bimodal respiration might meet their demands from water v. air has interested researchers for over a century. The challenges of measuring oxygen uptake from both water and air, preferably simultaneously, have been addressed in a variety of ways, which are briefly reviewed. These methods are not well-suited for the long-term measurements necessary to be certain of obtaining undisturbed patterns of respiratory partitioning, for example, to estimate traits such as standard metabolic rate. Such measurements require automated intermittent-closed respirometry that, for bimodal fishes, has only recently been developed. This paper describes two approaches in enough detail to be replicated by the interested researcher. These methods are for static respirometry. Measuring oxygen uptake by bimodal fishes during exercise poses specific challenges, which are described to aid the reader in designing experiments. The respiratory physiology and behaviour of air-breathing fishes is very complex and can easily be influenced by experimental conditions, and some general considerations are listed to facilitate the design of experiments. Air breathing is believed to have evolved in response to aquatic hypoxia and, probably, associated hypercapnia. The review ends by considering what realistic hypercapnia is, how hypercapnic tropical waters can become and how this might influence bimodal animals' gas exchange.  
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  Volume de collection Numéro de collection Edition  
  ISSN 1095-8649 ISBN Médium  
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  Numéro d'Appel MARBEC @ alain.herve @ collection 1536  
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Auteur Lefevre, S.; Mckenzie, D.J.; Nilsson, G.E. doi  openurl
  Titre Models projecting the fate of fish populations under climate change need to be based on valid physiological mechanisms Type Article scientifique
  Année 2017 Publication Revue Abrégée Glob. Change Biol.  
  Volume 23 Numéro 9 Pages 3449-3459  
  Mots-Clés aerobic scope; coryphaena-hippurus; energy-demand teleosts; gadus-morhua l; gill surface area; growth; makaira-nigricans; marlin tetrapturus-albidus; metabolism; metabolism-size relationship; oxygen consumption; oxygen-consumption; ram ventilation; Respiration; scaling; swimming performance; tuna katsuwonus-pelamis  
  Résumé Some recent modelling papers projecting smaller fish sizes and catches in a warmer future are based on erroneous assumptions regarding (i) the scaling of gills with body mass and (ii) the energetic cost of 'maintenance'. Assumption (i) posits that insurmountable geometric constraints prevent respiratory surface areas from growing as fast as body volume. It is argued that these constraints explain allometric scaling of energy metabolism, whereby larger fishes have relatively lower mass-specific metabolic rates. Assumption (ii) concludes that when fishes reach a certain size, basal oxygen demands will not be met, because of assumption (i). We here demonstrate unequivocally, by applying accepted physiological principles with reference to the existing literature, that these assumptions are not valid. Gills are folded surfaces, where the scaling of surface area to volume is not constrained by spherical geometry. The gill surface area can, in fact, increase linearly in proportion to gill volume and body mass. We cite the large body of evidence demonstrating that respiratory surface areas in fishes reflect metabolic needs, not vice versa, which explains the large interspecific variation in scaling of gill surface areas. Finally, we point out that future studies basing their predictions on models should incorporate factors for scaling of metabolic rate and for temperature effects on metabolism, which agree with measured values, and should account for interspecific variation in scaling and temperature effects. It is possible that some fishes will become smaller in the future, but to make reliable predictions the underlying mechanisms need to be identified and sought elsewhere than in geometric constraints on gill surface area. Furthermore, to ensure that useful information is conveyed to the public and policymakers about the possible effects of climate change, it is necessary to improve communication and congruity between fish physiologists and fisheries scientists.  
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  Volume de collection Numéro de collection Edition  
  ISSN 1354-1013 ISBN Médium  
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  Numéro d'Appel MARBEC @ alain.herve @ collection 2169  
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Auteur Galasso, H.L.; Richard, M.; Lefebvre, S.; Aliaume, C.; Callier, M.D. doi  openurl
  Titre Body size and temperature effects on standard metabolic rate for determining metabolic scope for activity of the polychaete Hediste (Nereis) diversicolor Type Article scientifique
  Année 2018 Publication Revue Abrégée PeerJ  
  Volume 6 Numéro Pages e5675  
  Mots-Clés adaptation; Aerobic scope; Allometric coefficient; annelida; Annelida; Arrhenius temperature; Deposit-feeder; growth; Growth; muller; nereididae; Oxygen consumption; oxygen-uptake; populations; respiration; salinity; ventilation  
  Résumé Considering the ecological importance and potential value of Hediste diversicolor, a better understanding of its metabolic rate and potential growth rates is required. The aims of this study are: (i) to describe key biometric relationships; (ii) to test the effects of temperature and body size on standard metabolic rate (as measure by oxygen consumption) to determine critical parameters, namely Arrhenius temperature (T-A), allometric coefficient (b) and reaction rate; and (iii) to determine the metabolic scope for activity (MSA) of H. diversicolor for further comparison with published specific growth rates. Individuals were collected in a Mediterranean lagoon (France). After 10 days of acclimatization, 7 days at a fixed temperature and 24 h of fasting, resting oxygen consumption rates (VO2) were individually measured in the dark at four different temperatures (11, 17, 22 and 27 degrees C) in worms weighing from 4 to 94 mgDW (n = 27 per temperature). Results showed that DW and L3 were the most accurate measurements of weight and length, respectively, among all the metrics tested. Conversion of WW (mg), DW (mg) and L3 (mm) were quantified with the following equations: DW = 0.15 x WW, L3 = 0.025 x TL(mm) + 1.44 and DW = 0.8 x L3(3.68). Using an equation based on temperature and allometric effects, the allometric coefficient (b) was estimated at 0.8 for DW and at 2.83 for L3. The reaction rate (VO2) equaled to 12.33 mu mol gDW(-1) h(-1) and 0.05 mu mol mm L3(-1) h(-)(1) at the reference temperature (20 degrees C, 293.15 K). Arrhenius temperature (T-A) was 5,707 and 5,664 K (for DW and L3, respectively). Metabolic scope for activity ranged from 120.1 to 627.6 J gDW(-1) d(-1). Predicted maximum growth rate increased with temperature, with expected values of 7-10% in the range of 15-20 degrees C. MSA was then used to evaluate specific growth rates (SGR) in several experiments. This paper may be used as a reference and could have interesting applications in the fields of aquaculture, ecology and biogeochemical processes.  
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  Langue English Langue du Résumé Titre Original  
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  Volume de collection Numéro de collection Edition  
  ISSN 2167-8359 ISBN Médium  
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  Numéro d'Appel MARBEC @ alain.herve @ collection 2443  
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Auteur Richard, M.; Bourreau, J.; Montagnani, C.; Ouisse, V.; Le Gall, P.; Fortune, M.; Munaron, D.; Messiaen, G.; Callier, M.D.; Roque d'Orbcastel, E. doi  openurl
  Titre Influence of OSHV-1 oyster mortality episode on dissolved inorganic fluxes: An ex situ experiment at the individual scale Type Article scientifique
  Année 2017 Publication Revue Abrégée Aquaculture  
  Volume 475 Numéro Pages 40-51  
  Mots-Clés carrying-capacity; Crassostrea gigas; crassostrea-gigas spat; eastern oyster; juvenile; la-madeleine quebec; mediterranean thau lagoon; Mineralisation; mortality; mussel mytilus-edulis; mu-var; Nutrient fluxes; Ostreid herpesvirus 1; ostreid herpesvirus-1 infection; oxygen consumption; oxygen-consumption rates; pacific oysters; Spat  
  Résumé Ostreid herpesvirus 1 (OsHV-1 mu var) infection has caused significant mortalities in juvenile oysters (Crassostrea gigas). In contrast to the practices of other animal production industries, sick and dead oysters are not separated from live ones and are left to decay in the surrounding environment, with unknown consequences on fluxes of dissolved materials. A laboratory approach was used in this study to test the influence of oyster mortality episode on dissolved inorganic fluxes at the oyster interface, dissociating (i) the effect of viral infection on metabolism of juvenile oysters and (ii) the effect of flesh decomposition on oxygen consumption and nutrient releases at the individual scale. Nine batches of juvenile oysters (Individual Total wet weight 1 g) were infected via injection of OsHV-1 enriched inoculums at different viral loads (108 and 109 OsHV-1 DNA copies per oyster) to explore infection thresholds. Oysters injected with filtered seawater were used as controls (C). Oysters were maintained under standard conditions to avoid stress linked to hypoxia, starvation, or ammonia excess. Before, after the injection and during the mortality episode, i.e. at days 1, 3, 7, 10 and 14, nine oysters per treatment were incubated in individual metabolic chambers to quantify oxygen, ammonium and phosphate fluxes at the seawater-oyster interface. Nine empty chambers served as a reference. Injections of the two viral loads of OsHV-1 induced similar mortality rates (38%), beginning at day 3 and lasting until day 14. The observed mortality kinetics were slower than those reported in previous experimental pathology studies, but comparable to those observed in the field (Thau lagoon, France). This study highlights that oxygen and nutrient fluxes significantly varied during mortality episode. Indeed (i) OsHV-1 infection firstly modifies oyster metabolism, with significant decreases in oxygen consumption and ammonium excretion, and (ii) dead oysters lead to a strong increase of ammonium (6 fold) and phosphate (41 fold) fluxes and a decrease in the N/P ratio due to mineralisation of their flesh. The latter may modify the structure of the planktonic community in the field during mortality episode. This study is a first step of the MORTAFLUX program. The second step was to in situ confirm this abnormal nutrient loading during a mortality episode and show its impact on bacterio-, phyto-and protozoo-plankton. (C) 2017 Elsevier B.V. All rights reserved.  
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  ISSN 0044-8486 ISBN Médium  
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  Numéro d'Appel MARBEC @ alain.herve @ collection 2149  
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Auteur Rissoli, R.Z.; Abdalla, F.C.; Costa, M.J.; Rantin, F.T.; McKenzie, D.J.; Kalinin, A.L. doi  openurl
  Titre Effects of glyphosate and the glyphosate based herbicides Roundup Original (R) and Roundup Transorb (R) on respiratory morphophysiology of bullfrog tadpoles Type Article scientifique
  Année 2016 Publication Revue Abrégée Chemosphere  
  Volume 156 Numéro Pages 37-44  
  Mots-Clés Hypoxia; Oxygen consumption; Respirometry; Glyphosate; Lithobates catesbeianus tadpoles; Skin morphology  
  Résumé Glyphosate-based herbicides are widely used in agriculture and are commonly found in water bodies. Roundup Original (R) (RO) contains an isopropylamine glyphosate (GLY) salt containing the surfactant POEA, while Roundup Transorb R (R) (RTR) contains a potassium salt of GLY with unknown surfactants. Both contain different compositions of so-called “inert” ingredients, more toxic than glyphosate. Amphibian tadpoles often experience variations in O-2 availability in their aquatic habitats; an ability to tolerate hypoxia can condition their survival and fitness. We evaluated the impacts of sublethal concentrations of GLY (1 mg L-1), RO (1 mg L-1 GLY a.e) and RTR (1 mg L-1 GLY a.e) on metabolic rate ((V)over dot O-2 – mLO(2) Kg1 h(-1)) of bullfrog tadpoles during normoxia and graded hypoxia, and related this to morphology of their skin, their major site of gas exchange. In control (CT) (V)over dot O-2 remained unaltered from normoxia until 40 mmHg, indicating a critical O-2 tension between 40 and 20 mmHg. GLY significantly reduced (V)over dot O-2, possibly due to epidermal hypertrophy, which increased O-2 diffusion distance to O-2 uptake. In contrast, RTR increased (V)over dot O-2 during hypoxia, indicating an influence of “inert” compounds and surfactants. (V)over dot O-2 of RO did not differ from CT, suggesting that any increase in (V)over dot O-2 caused by exposure was antagonized by epidermal hypertrophy. Indeed, all herbicides caused marked alterations in skin morphology, with cell and epithelium wall presenting hyperplasia or hypertrophy and chromatid rupture. In summary, GLY, RO and RTR exert different effects in bullfrog tadpoles, in particular the surfactants and inert compounds appear to influence oxygen uptake. (C) 2016 Elsevier Ltd. All rights reserved.  
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  Éditeur de collection Titre de collection Titre de collection Abrégé  
  Volume de collection Numéro de collection Edition  
  ISSN 0045-6535 ISBN Médium  
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  Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 2407  
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