1
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Zambie AD, Ackerly KL, Negrete B, Esbaugh AJ. Warming-induced "plastic floors" improve hypoxia vulnerability, not aerobic scope, in red drum (Sciaenops ocellatus). THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 922:171057. [PMID: 38378061 DOI: 10.1016/j.scitotenv.2024.171057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Revised: 01/19/2024] [Accepted: 02/15/2024] [Indexed: 02/22/2024]
Abstract
Ocean warming is a prevailing threat to marine ectotherms. Recently the "plastic floors, concrete ceilings" hypothesis was proposed, which suggests that a warmed fish will acclimate to higher temperatures by reducing standard metabolic rate (SMR) while keeping maximum metabolic rate (MMR) stable, therefore improving aerobic scope (AS). Here we evaluated this hypothesis on red drum (Sciaenops ocellatus) while incorporating measures of hypoxia vulnerability (critical oxygen threshold; Pcrit) and mitochondrial performance. Fish were subjected to a 12-week acclimation to 20 °C or 28 °C. Respirometry was performed every 4 weeks to obtain metabolic rate and Pcrit; mitochondrial respirometry was performed on liver and heart samples at the end of the acclimation. 28 °C fish had a significantly higher SMR, MMR, and Pcrit than 20 °C controls at time 0, but SMR declined by 36.2 % over the 12-week acclimation. No change in SMR was observed in the control treatment. Contrary to expectations, SMR suppression did not improve AS relative to time 0 owing to a progressive decline in MMR over acclimation time. Pcrit decreased by 27.2 % in the warm-acclimated fishes, which resulted in temperature treatments having statistically similar values by 12-weeks. No differences in mitochondrial traits were observed in the heart - despite a Δ8 °C assay temperature - while liver respiratory and coupling control ratios were significantly improved, suggesting that mitochondrial plasticity may contribute to the reduced SMR with warming. Overall, this work suggests that warming induced metabolic suppression offsets the deleterious consequences of high oxygen demand on hypoxia vulnerability, and in so doing greatly expands the theoretical range of metabolically available habitats for red drum.
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Affiliation(s)
- Adam D Zambie
- Department of Marine Science, University of Texas at Austin, Port Aransas, TX 78373, United States; Department of Biological Sciences, Idaho State University, Pocatello, ID 83209, United States
| | - Kerri Lynn Ackerly
- Department of Marine Science, University of Texas at Austin, Port Aransas, TX 78373, United States
| | - Benjamin Negrete
- Department of Marine Science, University of Texas at Austin, Port Aransas, TX 78373, United States; Department of Zoology, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
| | - Andrew J Esbaugh
- Department of Marine Science, University of Texas at Austin, Port Aransas, TX 78373, United States.
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2
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Baag S, Mandal S. Combined effects of ocean warming and acidification on marine fish and shellfish: A molecule to ecosystem perspective. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 802:149807. [PMID: 34450439 DOI: 10.1016/j.scitotenv.2021.149807] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Revised: 08/06/2021] [Accepted: 08/17/2021] [Indexed: 06/13/2023]
Abstract
It is expected that by 2050 human population will exceed nine billion leading to increased pressure on marine ecosystems. Therefore, it is conjectured various levels of ecosystem functioning starting from individual to population-level, species distribution, food webs and trophic interaction dynamics will be severely jeopardized in coming decades. Ocean warming and acidification are two prime threats to marine biota, yet studies about their cumulative effect on marine fish and shellfishes are still in its infancy. This review assesses existing information regarding the interactive effects of global environmental factors like warming and acidification in the perspective of marine capture fisheries and aquaculture industry. As climate change continues, distribution pattern of species is likely to be altered which will impact fisheries and fishing patterns. Our work is an attempt to compile the existing literatures in the biological perspective of the above-mentioned stressors and accentuate a clear outline of knowledge in this subject. We reviewed studies deciphering the biological consequences of warming and acidification on fish and shellfishes in the light of a molecule to ecosystem perspective. Here, for the first time impacts of these two global environmental drivers are discussed in a holistic manner taking into account growth, survival, behavioural response, prey predator dynamics, calcification, biomineralization, reproduction, physiology, thermal tolerance, molecular level responses as well as immune system and disease susceptibility. We suggest urgent focus on more robust, long term, comprehensive and ecologically realistic studies that will significantly contribute to the understanding of organism's response to climate change for sustainable capture fisheries and aquaculture.
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Affiliation(s)
- Sritama Baag
- Marine Ecology Laboratory, Department of Life Sciences, Presidency University, 86/1, College Street, Kolkata 700073, India
| | - Sumit Mandal
- Marine Ecology Laboratory, Department of Life Sciences, Presidency University, 86/1, College Street, Kolkata 700073, India.
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3
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Le Roy A, Mazué GPF, Metcalfe NB, Seebacher F. Diet and temperature modify the relationship between energy use and ATP production to influence behavior in zebrafish ( Danio rerio). Ecol Evol 2021; 11:9791-9803. [PMID: 34306662 PMCID: PMC8293724 DOI: 10.1002/ece3.7806] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Revised: 05/13/2021] [Accepted: 06/02/2021] [Indexed: 11/14/2022] Open
Abstract
Food availability and temperature influence energetics of animals and can alter behavioral responses such as foraging and spontaneous activity. Food availability, however, is not necessarily a good indicator of energy (ATP) available for cellular processes. The efficiency of energy transduction from food-derived substrate to ATP in mitochondria can change with environmental context. Our aim was to determine whether the interaction between food availability and temperature affects mitochondrial efficiency and behavior in zebrafish (Danio rerio). We conducted a fully factorial experiment to test the effects of feeding frequency, acclimation temperature (three weeks to 18 or 28°C), and acute test temperature (18 and 28°C) on whole-animal oxygen consumption, mitochondrial bioenergetics and efficiency (ADP consumed per oxygen atom; P:O ratio), and behavior (boldness and exploration). We show that infrequently fed (once per day on four days per week) zebrafish have greater mitochondrial efficiency than frequently fed (three times per day on five days per week) animals, particularly when warm-acclimated. The interaction between temperature and feeding frequency influenced exploration of a novel environment, but not boldness. Both resting rate of producing ATP and scope for increasing it were positively correlated with time spent exploring and distance moved in standardized trials. In contrast, behavior was not associated with whole-animal aerobic (oxygen consumption) scope, but exploration was positively correlated with resting oxygen consumption rates. We highlight the importance of variation in both metabolic (oxygen consumption) rate and efficiency of producing ATP in determining animal performance and behavior. Oxygen consumption represents energy use, and P:O ratio is a variable that determines how much of that energy is allocated to ATP production. Our results emphasize the need to integrate whole-animal responses with subcellular traits to evaluate the impact of environmental conditions on behavior and movement.
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Affiliation(s)
- Amélie Le Roy
- School of Life and Environmental SciencesUniversity of SydneySydneyNSWAustralia
| | | | - Neil B. Metcalfe
- Institute of Biodiversity, Animal Health and Comparative MedicineUniversity of GlasgowGlasgowUK
| | - Frank Seebacher
- School of Life and Environmental SciencesUniversity of SydneySydneyNSWAustralia
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4
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Paul N, Novais SC, Silva CSE, Mendes S, Kunzmann A, Lemos MFL. Global warming overrides physiological anti-predatory mechanisms in intertidal rock pool fish Gobius paganellus. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 776:145736. [PMID: 33640546 DOI: 10.1016/j.scitotenv.2021.145736] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Revised: 02/03/2021] [Accepted: 02/04/2021] [Indexed: 06/12/2023]
Abstract
In nature, a multitude of factors influences the fitness of an organism at a given time, which makes single stressor assessments far from ecologically relevant scenarios. This study focused on the effects of water temperature and predation stress on the metabolism and body mass gain of a common intertidal rock pool fish, Gobius paganellus, addressing the following hypotheses: (1) the energy metabolism of G. paganellus under predation stress is reduced; (2) G. paganellus shows thermal compensation under heat stress; and (3) thermal stress is the dominant stressor that may override predation stress responses. Individuals were exposed to simulated predation stress and temperature increase from 20 °C to 29 °C, and both stressors combined. Physiological effects were addressed using biochemical biomarkers related with energy metabolism (isocitrate dehydrogenase, lactate dehydrogenase, energy available, energy consumption rates), oxidative stress (superoxide dismutase, catalase, DNA damage, lipid peroxidation), and biotransformation (glutathione-S-transferase). The results of this study revealed that predation stress reduced the cellular metabolism of G. paganellus, and enhanced storage of protein reserves. As hypothesized, hyperthermia decreased the aerobic mitochondrial metabolism, indicating thermal compensation mechanisms to resist against unfavourable temperatures. Hyperthermia was the dominant stressor overriding the physiological responses to predation stress. Both stressors combined might further have synergistically activated detoxification pathways, even though not strong enough to counteract lipid peroxidation and DNA damage completely. The synergistic effect of combined thermal and predation stress thus may not only increase the risk of being preyed upon, but also may indicate extra energy trade-off for the basal metabolism, which in turn may have ecologically relevant consequences for general body functions such as somatic growth and reproduction. The present findings clearly underline the ecological importance of multi-stressor assessments to provide a better and holistic picture of physiological responses towards more realistic evaluations of climate change consequences for intertidal populations.
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Affiliation(s)
- Nina Paul
- Leibniz Centre for Tropical Marine Research (ZMT), Fahrenheitstr. 6, 28359 Bremen, Germany.
| | - Sara C Novais
- MARE - Marine and Environmental Sciences Centre, ESTM, Instituto Politécnico de Leiria, 2520 - 630 Peniche, Portugal
| | - Cátia S E Silva
- MARE - Marine and Environmental Sciences Centre, ESTM, Instituto Politécnico de Leiria, 2520 - 630 Peniche, Portugal
| | - Susana Mendes
- MARE - Marine and Environmental Sciences Centre, ESTM, Instituto Politécnico de Leiria, 2520 - 630 Peniche, Portugal
| | - Andreas Kunzmann
- Leibniz Centre for Tropical Marine Research (ZMT), Fahrenheitstr. 6, 28359 Bremen, Germany
| | - Marco F L Lemos
- MARE - Marine and Environmental Sciences Centre, ESTM, Instituto Politécnico de Leiria, 2520 - 630 Peniche, Portugal.
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5
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Jutfelt F, Norin T, Åsheim ER, Rowsey LE, Andreassen AH, Morgan R, Clark TD, Speers‐Roesch B. ‘Aerobic scope protection’ reduces ectotherm growth under warming. Funct Ecol 2021. [DOI: 10.1111/1365-2435.13811] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Fredrik Jutfelt
- Department of Biology Norwegian University of Science and Technology Trondheim Norway
| | - Tommy Norin
- DTU Aqua: National Institute of Aquatic Resources Technical University of Denmark Kgs. Lyngby Denmark
| | - Eirik R. Åsheim
- Department of Biology Norwegian University of Science and Technology Trondheim Norway
- Organismal and Evolutionary Biology Research Programme Institute of Biotechnology University of Helsinki Helsinki Finland
| | - Lauren E. Rowsey
- Department of Biological Sciences University of New Brunswick Saint John NB Canada
| | - Anna H. Andreassen
- Department of Biology Norwegian University of Science and Technology Trondheim Norway
| | - Rachael Morgan
- Department of Biology Norwegian University of Science and Technology Trondheim Norway
| | - Timothy D. Clark
- School of Life and Environmental Sciences Deakin University Geelong Vic. Australia
| | - Ben Speers‐Roesch
- Department of Biological Sciences University of New Brunswick Saint John NB Canada
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6
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Varying heat tolerance among Arctic nearshore fishes. Polar Biol 2021. [DOI: 10.1007/s00300-021-02815-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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7
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Sokolova I. Bioenergetics in environmental adaptation and stress tolerance of aquatic ectotherms: linking physiology and ecology in a multi-stressor landscape. J Exp Biol 2021; 224:224/Suppl_1/jeb236802. [PMID: 33627464 DOI: 10.1242/jeb.236802] [Citation(s) in RCA: 49] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Energy metabolism (encompassing energy assimilation, conversion and utilization) plays a central role in all life processes and serves as a link between the organismal physiology, behavior and ecology. Metabolic rates define the physiological and life-history performance of an organism, have direct implications for Darwinian fitness, and affect ecologically relevant traits such as the trophic relationships, productivity and ecosystem engineering functions. Natural environmental variability and anthropogenic changes expose aquatic ectotherms to multiple stressors that can strongly affect their energy metabolism and thereby modify the energy fluxes within an organism and in the ecosystem. This Review focuses on the role of bioenergetic disturbances and metabolic adjustments in responses to multiple stressors (especially the general cellular stress response), provides examples of the effects of multiple stressors on energy intake, assimilation, conversion and expenditure, and discusses the conceptual and quantitative approaches to identify and mechanistically explain the energy trade-offs in multiple stressor scenarios, and link the cellular and organismal bioenergetics with fitness, productivity and/or ecological functions of aquatic ectotherms.
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Affiliation(s)
- Inna Sokolova
- Marine Biology Department, Institute of Biological Sciences, University of Rostock, 18059 Rostock, Germany .,Department of Maritime Systems, Interdisciplinary Faculty, University of Rostock, 18059 Rostock, Germany
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8
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Gerber L, Clow KA, Gamperl AK. Acclimation to warm temperatures has important implications for mitochondrial function in Atlantic salmon ( Salmo salar). J Exp Biol 2021; 224:jeb236257. [PMID: 33288533 DOI: 10.1242/jeb.236257] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2020] [Accepted: 12/01/2020] [Indexed: 12/16/2022]
Abstract
In fish, the capacity of thermal acclimation to preserve cardiac mitochondrial function under future warming scenarios is important to understand given the central roles that cardiac energy metabolism and performance play in this taxa's thermal tolerance. We acclimated Atlantic salmon to 12 and 20°C (for >2 months), and investigated the effects of acute and chronic warming on cardiac mitochondrial respiration and reactive oxygen species (ROS) production (release rate) using high-resolution fluorespirometry. Further, we compared the sensitivity of mitochondrial respiration to nitric oxide (i.e. the NO IC50), and assessed the mitochondrial response to anoxia-reoxygenation (AR). Acute exposure to 20°C increased maximal mitochondrial respiration by ∼55%; however, the mitochondria's complex I respiratory control ratio was 17% lower and ROS production was increased by ≥60%. Acclimation to 20°C: (1) preserved mitochondrial coupling and aerobic capacity; (2) decreased the mitochondria's ROS production by ∼30%; (3) increased the mitochondria's NO IC50 by ∼23%; and (4) improved mitochondrial membrane integrity at 20°C. AR did not affect mitochondrial function at 12°C, but acute exposure to 20°C and AR depressed maximal mitochondrial respiration (by ∼9%) and coupling (by ∼16%) without impacting ROS production. Finally, warm acclimation did not improve the capacity of mitochondria to recover from AR, indicating that there was no 'cross-tolerance' between these challenges. Our findings provide compelling evidence that thermal plasticity of cardiac mitochondrial function contributes to the Atlantic salmon's capability to survive at ≥20°C for prolonged periods, but call into question whether this plasticity may allow them to withstand high temperatures when combined with other stressors.
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Affiliation(s)
- Lucie Gerber
- Department of Ocean Sciences, Memorial University, St. John's, NL A1C 5S7, Canada
| | - Kathy A Clow
- Department of Ocean Sciences, Memorial University, St. John's, NL A1C 5S7, Canada
| | - Anthony K Gamperl
- Department of Ocean Sciences, Memorial University, St. John's, NL A1C 5S7, Canada
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9
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Gerber L, Clow KA, Mark FC, Gamperl AK. Improved mitochondrial function in salmon (Salmo salar) following high temperature acclimation suggests that there are cracks in the proverbial 'ceiling'. Sci Rep 2020; 10:21636. [PMID: 33303856 PMCID: PMC7729908 DOI: 10.1038/s41598-020-78519-4] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Accepted: 11/22/2020] [Indexed: 11/09/2022] Open
Abstract
Mitochondrial function can provide key insights into how fish will respond to climate change, due to its important role in heart performance, energy metabolism and oxidative stress. However, whether warm acclimation can maintain or improve the energetic status of the fish heart when exposed to short-term heat stress is not well understood. We acclimated Atlantic salmon, a highly aerobic eurythermal species, to 12 and 20 °C, then measured cardiac mitochondrial functionality and integrity at 20 °C and at 24, 26 and 28 °C (this species' critical thermal maximum ± 2 °C). Acclimation to 20 °C vs. 12 °C enhanced many aspects of mitochondrial respiratory capacity and efficiency up to 24 °C, and preserved outer mitochondrial membrane integrity up to 26 °C. Further, reactive oxygen species (ROS) production was dramatically decreased at all temperatures. These data suggest that salmon acclimated to 'normal' maximum summer temperatures are capable of surviving all but the most extreme ocean heat waves, and that there is no 'tradeoff' in heart mitochondrial function when Atlantic salmon are acclimated to high temperatures (i.e., increased oxidative phosphorylation does not result in heightened ROS production). This study suggests that fish species may show quite different acclimatory responses when exposed to prolonged high temperatures, and thus, susceptibility to climate warming.
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Affiliation(s)
- Lucie Gerber
- Department of Ocean Sciences, Memorial University, St. John's, NL, Canada.
| | - Kathy A Clow
- Department of Ocean Sciences, Memorial University, St. John's, NL, Canada
| | - Felix C Mark
- Section Integrative Ecophysiology, Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Bremerhaven, Germany
| | - Anthony K Gamperl
- Department of Ocean Sciences, Memorial University, St. John's, NL, Canada
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10
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Pichaud N, Ekström A, Breton S, Sundström F, Rowinski P, Blier PU, Sandblom E. Adjustments of cardiac mitochondrial phenotype in a warmer thermal habitat is associated with oxidative stress in European perch, Perca fluviatilis. Sci Rep 2020; 10:17697. [PMID: 33077851 PMCID: PMC7572411 DOI: 10.1038/s41598-020-74788-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Accepted: 09/18/2020] [Indexed: 12/18/2022] Open
Abstract
Mitochondria are playing key roles in setting the thermal limits of fish, but how these organelles participate in selection mechanisms during extreme thermal events associated with climate warming in natural populations is unclear. Here, we investigated the thermal effects on mitochondrial metabolism, oxidative stress, and mitochondrial gene expression in cardiac tissues of European perch (Perca fluviatilis) collected from an artificially heated ecosystem, the "Biotest enclosure", and an adjacent reference area in the Baltic sea with normal temperatures (~ 23 °C and ~ 16 °C, respectively, at the time of capture in summer). Fish were sampled one month after a heat wave that caused the Biotest temperatures to peak at ~ 31.5 °C, causing significant mortality. When assayed at 23 °C, Biotest perch maintained high mitochondrial capacities, while reference perch displayed depressed mitochondrial functions relative to measurements at 16 °C. Moreover, mitochondrial gene expression of nd4 (mitochondrial subunit of complex I) was higher in Biotest fish, likely explaining the increased respiration rates observed in this population. Nonetheless, cardiac tissue from Biotest perch displayed higher levels of oxidative damage, which may have resulted from their chronically warm habitat, as well as the extreme temperatures encountered during the preceding summer heat wave. We conclude that eurythermal fish such as perch are able to adjust and maintain mitochondrial capacities of highly aerobic organs such as the heart when exposed to a warming environment as predicted with climate change. However, this might come at the expense of exacerbated oxidative stress, potentially threatening performance in nature.
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Affiliation(s)
- Nicolas Pichaud
- Department of Chemistry and Biochemistry, Université de Moncton, Moncton, NB, E1A 3E9, Canada. .,Department of Biological and Environmental Sciences, University of Gothenburg, 405 30, Gothenburg, Sweden. .,Department of Biology, Université du Québec à Rimouski, Rimouski, QC, G5L 3A1, Canada.
| | - Andreas Ekström
- Department of Biological and Environmental Sciences, University of Gothenburg, 405 30, Gothenburg, Sweden
| | - Sophie Breton
- Department of Biological Sciences, Université de Montréal, Montréal, QC, H2V 2S9, Canada
| | - Fredrik Sundström
- Department of Ecology and Genetics, Uppsala University, 752 36, Uppsala, Sweden
| | - Piotr Rowinski
- Department of Ecology and Genetics, Uppsala University, 752 36, Uppsala, Sweden
| | - Pierre U Blier
- Department of Biology, Université du Québec à Rimouski, Rimouski, QC, G5L 3A1, Canada
| | - Erik Sandblom
- Department of Biological and Environmental Sciences, University of Gothenburg, 405 30, Gothenburg, Sweden
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11
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Little AG, Loughland I, Seebacher F. What do warming waters mean for fish physiology and fisheries? JOURNAL OF FISH BIOLOGY 2020; 97:328-340. [PMID: 32441327 DOI: 10.1111/jfb.14402] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Revised: 04/30/2020] [Accepted: 05/20/2020] [Indexed: 06/11/2023]
Abstract
Environmental signals act primarily on physiological systems, which then influence higher-level functions such as movement patterns and population dynamics. Increases in average temperature and temperature variability associated with global climate change are likely to have strong effects on fish physiology and thereby on populations and fisheries. Here we review the principal mechanisms that transduce temperature signals and the physiological responses to those signals in fish. Temperature has a direct, thermodynamic effect on biochemical reaction rates. Nonetheless, plastic responses to longer-term thermal signals mean that fishes can modulate their acute thermal responses to compensate at least partially for thermodynamic effects. Energetics are particularly relevant for growth and movement, and therefore for fisheries, and temperature can have pronounced effects on energy metabolism. All energy (ATP) production is ultimately linked to mitochondria, and temperature has pronounced effects on mitochondrial efficiency and maximal capacities. Mitochondria are dependent on oxygen as the ultimate electron acceptor so that cardiovascular function and oxygen delivery link environmental inputs with energy metabolism. Growth efficiency, that is the conversion of food into tissue, changes with temperature, and there are indications that warmer water leads to decreased conversion efficiencies. Moreover, movement and migration of fish relies on muscle function, which is partially dependent on ATP production but also on intracellular calcium cycling within the myocyte. Neuroendocrine processes link environmental signals to regulated responses at the level of different tissues, including muscle. These physiological processes within individuals can scale up to population responses to climate change. A mechanistic understanding of thermal responses is essential to predict the vulnerability of species and populations to climate change.
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Affiliation(s)
| | - Isabella Loughland
- School of Life and Environmental Sciences A08, University of Sydney, Sydney, Australia
| | - Frank Seebacher
- School of Life and Environmental Sciences A08, University of Sydney, Sydney, Australia
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12
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Wilson RE, Sonsthagen SA, Smé N, Gharrett AJ, Majewski AR, Wedemeyer K, Nelson RJ, Talbot SL. Mitochondrial genome diversity and population mitogenomics of polar cod (Boreogadus saida) and Arctic dwelling gadoids. Polar Biol 2020. [DOI: 10.1007/s00300-020-02703-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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13
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Leo E, Graeve M, Storch D, Pörtner HO, Mark FC. Impact of ocean acidification and warming on mitochondrial enzymes and membrane lipids in two Gadoid species. Polar Biol 2019. [DOI: 10.1007/s00300-019-02600-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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14
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Howald S, Cominassi L, LeBayon N, Claireaux G, Mark FC. Future ocean warming may prove beneficial for the northern population of European seabass, but ocean acidification will not. ACTA ACUST UNITED AC 2019; 222:jeb.213017. [PMID: 31624098 DOI: 10.1242/jeb.213017] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Accepted: 10/01/2019] [Indexed: 12/26/2022]
Abstract
The world's oceans are acidifying and warming as a result of increasing atmospheric CO2 concentrations. The thermal tolerance of fish greatly depends on the cardiovascular ability to supply the tissues with oxygen. The highly oxygen-dependent heart mitochondria thus might play a key role in shaping an organism's tolerance to temperature. The present study aimed to investigate the effects of acute and chronic warming on the respiratory capacity of European sea bass (Dicentrarchus labrax L.) heart mitochondria. We hypothesized that acute warming would impair mitochondrial respiratory capacity, but be compensated for by life-time conditioning. Increasing P CO2 may additionally cause shifts in metabolic pathways by inhibiting several enzymes of the cellular energy metabolism. Among other shifts in metabolic pathways, acute warming of heart mitochondria of cold life-conditioned fish increased leak respiration rate, suggesting a lower aerobic capacity to synthesize ATP with acute warming. However, thermal conditioning increased mitochondrial functionality, e.g. higher respiratory control ratios in heart mitochondria of warm life-conditioned compared with cold life-conditioned fish. Exposure to high P CO2 synergistically amplified the effects of acute and long-term warming, but did not result in changes by itself. This high ability to maintain mitochondrial function under ocean acidification can be explained by the fact that seabass are generally able to acclimate to a variety of environmental conditions. Improved mitochondrial energy metabolism after warm conditioning could be due to the origin of this species in the warm waters of the Mediterranean. Our results also indicate that seabass are not yet fully adapted to the colder temperatures in their northern distribution range and might benefit from warmer temperatures in these latitudes.
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Affiliation(s)
- Sarah Howald
- Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Integrative Ecophysiology, 27570 Bremerhaven, Germany .,Institute of Marine Ecosystem and Fisheries Science, Center for Earth System Research and Sustainability (CEN), University of Hamburg, 22767 Hamburg, Germany
| | - Louise Cominassi
- Institute of Marine Ecosystem and Fisheries Science, Center for Earth System Research and Sustainability (CEN), University of Hamburg, 22767 Hamburg, Germany
| | - Nicolas LeBayon
- Ifremer, LEMAR (UMR 6539), Laboratory of Adaptation, and Nutrition of Fish, Centre Ifremer de Bretagne, 29280 Plouzané, France
| | - Guy Claireaux
- Ifremer, LEMAR (UMR 6539), Laboratory of Adaptation, and Nutrition of Fish, Centre Ifremer de Bretagne, 29280 Plouzané, France.,Université de Bretagne Occidentale, LEMAR (UMR 6539), 29280 Plouzané, France
| | - Felix C Mark
- Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Integrative Ecophysiology, 27570 Bremerhaven, Germany
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15
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Cominassi L, Moyano M, Claireaux G, Howald S, Mark FC, Zambonino-Infante JL, Le Bayon N, Peck MA. Combined effects of ocean acidification and temperature on larval and juvenile growth, development and swimming performance of European sea bass (Dicentrarchus labrax). PLoS One 2019; 14:e0221283. [PMID: 31490944 PMCID: PMC6731055 DOI: 10.1371/journal.pone.0221283] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Accepted: 08/02/2019] [Indexed: 01/21/2023] Open
Abstract
Ocean acidification and ocean warming (OAW) are simultaneously occurring and could pose ecological challenges to marine life, particularly early life stages of fish that, although they are internal calcifiers, may have poorly developed acid-base regulation. This study assessed the effect of projected OAW on key fitness traits (growth, development and swimming ability) in European sea bass (Dicentrarchus labrax) larvae and juveniles. Starting at 2 days post-hatch (dph), larvae were exposed to one of three levels of PCO2 (650, 1150, 1700 μatm; pH 8.0, 7.8, 7.6) at either a cold (15°C) or warm (20°C) temperature. Growth rate, development stage and critical swimming speed (Ucrit) were repeatedly measured as sea bass grew from 0.6 to ~10.0 (cold) or ~14.0 (warm) cm body length. Exposure to different levels of PCO2 had no significant effect on growth, development or Ucrit of larvae and juveniles. At the warmer temperature, larvae displayed faster growth and deeper bodies. Notochord flexion occurred at 0.8 and 1.2 cm and metamorphosis was completed at an age of ~45 and ~60 days post-hatch for sea bass in the warm and cold treatments, respectively. Swimming performance increased rapidly with larval development but better swimmers were observed in the cold treatment, reflecting a potential trade-off between fast grow and swimming ability. A comparison of the results of this and other studies on marine fish indicates that the effects of OAW on the growth, development and swimming ability of early life stages are species-specific and that generalizing the impacts of climate-driven warming or ocean acidification is not warranted.
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Affiliation(s)
- Louise Cominassi
- Institute of Marine Ecosystem and Fisheries Science, Center for Earth System Research and Sustainability (CEN), University of Hamburg, Hamburg, Germany
| | - Marta Moyano
- Institute of Marine Ecosystem and Fisheries Science, Center for Earth System Research and Sustainability (CEN), University of Hamburg, Hamburg, Germany
| | - Guy Claireaux
- Université de Bretagne Occidentale, LEMAR (UMR 6539), Centre Ifremer de Bretagne, Plouzané, France
| | - Sarah Howald
- Institute of Marine Ecosystem and Fisheries Science, Center for Earth System Research and Sustainability (CEN), University of Hamburg, Hamburg, Germany
- Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Integrative Ecophysiology, Bremerhaven, Germany
| | - Felix C. Mark
- Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Integrative Ecophysiology, Bremerhaven, Germany
| | - José-Luis Zambonino-Infante
- Ifremer, LEMAR (UMR 6539), Laboratory of Adaptation, Reproduction and Nutrition of Fish, Centre Ifremer de Bretagne, Plouzané, France
| | - Nicolas Le Bayon
- Ifremer, LEMAR (UMR 6539), Laboratory of Adaptation, Reproduction and Nutrition of Fish, Centre Ifremer de Bretagne, Plouzané, France
| | - Myron A. Peck
- Institute of Marine Ecosystem and Fisheries Science, Center for Earth System Research and Sustainability (CEN), University of Hamburg, Hamburg, Germany
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16
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Gilbert MJH, Rani V, McKenzie SM, Farrell AP. Autonomic cardiac regulation facilitates acute heat tolerance in rainbow trout: in situ and in vivo support. ACTA ACUST UNITED AC 2019; 222:jeb.194365. [PMID: 31015284 DOI: 10.1242/jeb.194365] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Accepted: 04/10/2019] [Indexed: 12/27/2022]
Abstract
Acute warming in fish increases heart rate (f H) and cardiac output to peak values, after which performance plateaus or declines and arrhythmia may occur. This cardiac response can place a convective limitation on systemic oxygen delivery at high temperatures. To test the hypothesis that autonomic cardiac regulation protects cardiac performance in rainbow trout during acute warming, we investigated adrenergic and cholinergic regulation during the onset and progression of cardiac limitations. We explored the direct effects of adrenergic stimulation by acutely warming an in situ working perfused heart until arrhythmia occurred, cooling the heart to restore rhythmicity and rewarming with increasing adrenergic stimulation. Adrenergic stimulation produced a clear, dose-dependent increase in the temperature and peak f H achieved prior to the onset of arrhythmia. To examine how this adrenergic protection functions in conjunction with cholinergic vagal inhibition in vivo, rainbow trout fitted with ECG electrodes were acutely warmed in a respirometer until they lost equilibrium (CTmax) with and without muscarinic (atropine) and β-adrenergic (sotalol) antagonists. Trout exhibited roughly equal and opposing cholinergic and adrenergic tone on f H that persisted up to critical temperatures. β-Adrenergic blockade significantly lowered peak f H by 14-17%, while muscarinic blockade significantly lowered the temperature for peak f H by 2.0°C. Moreover, muscarinic and β-adrenergic blockers injected individually or together significantly reduced CTmax by up to 3°C, indicating for the first time that cardiac adrenergic stimulation and cholinergic inhibition can enhance acute heat tolerance in rainbow trout at the level of the heart and the whole animal.
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Affiliation(s)
- Matthew J H Gilbert
- Department of Zoology, University of British Columbia, 6270 University Boulevard, Vancouver, BC, Canada V6T 1Z4
| | - Varsha Rani
- Faculty of Land and Food Systems, University of British Columbia, 2357 Main Mall, Vancouver, BC, Canada V6T 1Z4
| | - Sean M McKenzie
- Department of Zoology, University of British Columbia, 6270 University Boulevard, Vancouver, BC, Canada V6T 1Z4
| | - Anthony P Farrell
- Department of Zoology, University of British Columbia, 6270 University Boulevard, Vancouver, BC, Canada V6T 1Z4.,Faculty of Land and Food Systems, University of British Columbia, 2357 Main Mall, Vancouver, BC, Canada V6T 1Z4
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17
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Kunz KL, Claireaux G, Pörtner HO, Knust R, Mark FC. Aerobic capacities and swimming performance of polar cod ( Boreogadus saida) under ocean acidification and warming conditions. J Exp Biol 2018; 221:jeb184473. [PMID: 30190318 PMCID: PMC6240293 DOI: 10.1242/jeb.184473] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Accepted: 09/01/2018] [Indexed: 01/09/2023]
Abstract
Polar cod (Boreogadus saida) is an important prey species in the Arctic ecosystem, yet its habitat is changing rapidly: climate change, through rising seawater temperatures and CO2 concentrations, is projected to be most pronounced in Arctic waters. This study aimed to investigate the influence of ocean acidification and warming on maximum performance parameters of B. saida as indicators for the species' acclimation capacities under environmental conditions projected for the end of this century. After 4 months at four acclimation temperatures (0, 3, 6, 8°C) each combined with two PCO2 levels (390 and 1170 µatm), aerobic capacities and swimming performance of B. saida were recorded following a Ucrit protocol. At both CO2 levels, standard metabolic rate (SMR) was elevated at the highest acclimation temperature indicating thermal limitations. Maximum metabolic rate (MMR) increased continuously with temperature, suggesting an optimum temperature for aerobic scope for exercise (ASex) at 6°C. Aerobic swimming performance (Ugait) increased with acclimation temperature irrespective of CO2 levels, while critical swimming speed (Ucrit) did not reveal any clear trend with temperature. Hypercapnia evoked an increase in MMR (and thereby ASex). However, swimming performance (both Ugait and Ucrit) was impaired under elevated near-future PCO2 conditions, indicating reduced efficiencies of oxygen turnover. The contribution of anaerobic metabolism to swimming performance was very low overall, and further reduced under hypercapnia. Our results revealed high sensitivities of maximum performance parameters (MMR, Ugait, Ucrit) of B. saida to ocean acidification. Impaired swimming capacity under ocean acidification may reflect reduced future competitive strength of B. saida.
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Affiliation(s)
- Kristina Lore Kunz
- Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Bentho-Pelagic Processes, Am Alten Hafen 26, 27568 Bremerhaven, Germany
- Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Integrative Ecophysiology, Am Handelshafen 12, 27570 Bremerhaven, Germany
- University of Bremen, Fachbereich 2, NW 2/Leobener Strasse, 28359 Bremen, Germany
| | - Guy Claireaux
- Université de Bretagne Occidentale, LEMAR (UMR 6539), Unité PFOM, Laboratoire ARN, Centre Ifremer de Brest, 29280 Plouzané, France
| | - Hans-Otto Pörtner
- Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Integrative Ecophysiology, Am Handelshafen 12, 27570 Bremerhaven, Germany
- University of Bremen, Fachbereich 2, NW 2/Leobener Strasse, 28359 Bremen, Germany
| | - Rainer Knust
- Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Bentho-Pelagic Processes, Am Alten Hafen 26, 27568 Bremerhaven, Germany
| | - Felix Christopher Mark
- Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Integrative Ecophysiology, Am Handelshafen 12, 27570 Bremerhaven, Germany
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18
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O'Brien KM, Rix AS, Egginton S, Farrell AP, Crockett EL, Schlauch K, Woolsey R, Hoffman M, Merriman S. Cardiac mitochondrial metabolism may contribute to differences in thermal tolerance of red- and white-blooded Antarctic notothenioid fishes. J Exp Biol 2018; 221:jeb177816. [PMID: 29895681 PMCID: PMC6104818 DOI: 10.1242/jeb.177816] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Accepted: 06/04/2018] [Indexed: 12/18/2022]
Abstract
Studies in temperate fishes provide evidence that cardiac mitochondrial function and the capacity to fuel cardiac work contribute to thermal tolerance. Here, we tested the hypothesis that decreased cardiac aerobic metabolic capacity contributes to the lower thermal tolerance of the haemoglobinless Antarctic icefish, Chaenocephalus aceratus, compared with that of the red-blooded Antarctic species, Notothenia coriiceps. Maximal activities of citrate synthase (CS) and lactate dehydrogenase (LDH), respiration rates of isolated mitochondria, adenylate levels and changes in mitochondrial protein expression were quantified from hearts of animals held at ambient temperature or exposed to their critical thermal maximum (CTmax). Compared with C. aceratus, activity of CS, ATP concentration and energy charge were higher in hearts of N. coriiceps at ambient temperature and CTmax While state 3 mitochondrial respiration rates were not impaired by exposure to CTmax in either species, state 4 rates, indicative of proton leakage, increased following exposure to CTmax in C. aceratus but not N. coriiceps The interactive effect of temperature and species resulted in an increase in antioxidants and aerobic metabolic enzymes in N. coriiceps but not in C. aceratus Together, our results support the hypothesis that the lower aerobic metabolic capacity of C. aceratus hearts contributes to its low thermal tolerance.
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Affiliation(s)
- Kristin M O'Brien
- Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, AK 99775, USA
| | - Anna S Rix
- Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, AK 99775, USA
| | - Stuart Egginton
- School of Biomedical Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - Anthony P Farrell
- Department of Zoology, University of British Columbia, Vancouver, BC, Canada, V6T 1Z4
| | | | - Karen Schlauch
- Department of Biochemistry and Molecular Biology, University of Nevada, Reno, NV 89557, USA
| | - Rebekah Woolsey
- Nevada Proteomics Center, University of Nevada, Reno, NV 89557, USA
| | - Megan Hoffman
- Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, AK 99775, USA
| | - Sean Merriman
- Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, AK 99775, USA
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19
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You Better Repeat It: Complex CO2 × Temperature Effects in Atlantic Silverside Offspring Revealed by Serial Experimentation. DIVERSITY 2018. [DOI: 10.3390/d10030069] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Concurrent ocean warming and acidification demand experimental approaches that assess biological sensitivities to combined effects of these potential stressors. Here, we summarize five CO2 × temperature experiments on wild Atlantic silverside, Menidia menidia, offspring that were reared under factorial combinations of CO2 (nominal: 400, 2200, 4000, and 6000 µatm) and temperature (17, 20, 24, and 28 °C) to quantify the temperature-dependence of CO2 effects in early life growth and survival. Across experiments and temperature treatments, we found few significant CO2 effects on response traits. Survival effects were limited to a single experiment, where elevated CO2 exposure reduced embryo survival at 17 and 24 °C. Hatch length displayed CO2 × temperature interactions due largely to reduced hatch size at 24 °C in one experiment but increased length at 28 °C in another. We found no overall influence of CO2 on larval growth or survival to 9, 10, 15 and 13–22 days post-hatch, at 28, 24, 20, and 17 °C, respectively. Importantly, exposure to cooler (17 °C) and warmer (28 °C) than optimal rearing temperatures (24 °C) in this species did not appear to increase CO2 sensitivity. Repeated experimentation documented substantial inter- and intra-experiment variability, highlighting the need for experimental replication to more robustly constrain inherently variable responses. Taken together, these results demonstrate that the early life stages of this ecologically important forage fish appear largely tolerate to even extreme levels of CO2 across a broad thermal regime.
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20
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Differences in neurochemical profiles of two gadid species under ocean warming and acidification. Front Zool 2017; 14:49. [PMID: 29093740 PMCID: PMC5661927 DOI: 10.1186/s12983-017-0238-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Accepted: 10/13/2017] [Indexed: 11/24/2022] Open
Abstract
Background Exposure to future ocean acidification scenarios may alter the behaviour of marine teleosts through interference with neuroreceptor functioning. So far, most studies investigated effects of ocean acidification on the behaviour of fish, either isolated or in combination with environmental temperature. However, only few physiological studies on this issue were conducted despite the putative neurophysiological origin of the CO2-induced behavioural changes. Here, we present the metabolic consequences of long-term exposure to projected ocean acidification (396–548 μatm PCO2 under control and 915–1272 μatm under treatment conditions) and parallel warming in the brain of two related fish species, polar cod (Boreogadus saida, exposed to 0 °C, 3 °C, 6 °C and 8 °C) and Atlantic cod (Gadus morhua, exposed to 3 °C, 8 °C, 12 °C and 16 °C). It has been shown that B. saida is behaviourally vulnerable to future ocean acidification scenarios, while G. morhua demonstrates behavioural resilience. Results We found that temperature alters brain osmolyte, amino acid, choline and neurotransmitter concentrations in both species indicating thermal responses particularly in osmoregulation and membrane structure. In B. saida, changes in amino acid and osmolyte metabolism at the highest temperature tested were also affected by CO2, possibly emphasizing energetic limitations. We did not observe changes in neurotransmitters, energy metabolites, membrane components or osmolytes that might serve as a compensatory mechanism against CO2 induced behavioural impairments. In contrast to B. saida, such temperature limitation was not detected in G. morhua; however, at 8 °C, CO2 induced an increase in the levels of metabolites of the glutamate/GABA-glutamine cycle potentially indicating greater GABAergic activity in G.morhua. Further, increased availability of energy-rich substrates was detected under these conditions. Conclusions Our results indicate a change of GABAergic metabolism in the nervous system of Gadus morhua close to the optimum of the temperature range. Since a former study showed that juvenile G. morhua might be slightly more behaviourally resilient to CO2 at this respective temperature, we conclude that the observed change of GABAergic metabolism could be involved in counteracting OA induced behavioural changes. This may serve as a fitness advantage of this respective species compared to B. saida in a future warmer, more acidified polar ocean. Electronic supplementary material The online version of this article (10.1186/s12983-017-0238-5) contains supplementary material, which is available to authorized users.
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21
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Arntzen JW, de Vries W, Canestrelli D, Martínez-Solano I. Hybrid zone formation and contrasting outcomes of secondary contact over transects in common toads. Mol Ecol 2017; 26:5663-5675. [PMID: 28752635 DOI: 10.1111/mec.14273] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2016] [Revised: 07/21/2017] [Accepted: 07/24/2017] [Indexed: 01/05/2023]
Abstract
Much progress in speciation research stems from documenting patterns of morphological and genetic variation in hybrid zones. Contrasting patterns of marker introgression in different sections of the contact can provide valuable insights on the relative importance of various evolutionary mechanisms maintaining species differences in the face of hybridization and gene flow and on hybrid zone temporal and spatial dynamics. We studied species interactions in the common toads Bufo bufo and B. spinosus in France and northwestern Italy using morphological and molecular data from the mitochondrial and nuclear genomes in an extensive survey, including two independent transects west and east of the Alps. At both, we found sharp, coincident and concordant nuclear genetic transitions. However, morphological clines were wider or absent and mtDNA introgression was asymmetric. We discuss alternative, nonexclusive hypotheses about evolutionary processes generating these patterns, including drift, selection, long-distance dispersal and spatial shifts in hybrid zone location and structure. The distribution of intraspecific mtDNA lineages supports a scenario in which B. bufo held a local refugium during the last glacial maximum. Present-day genetic profiles are best explained by an advance of B. spinosus from a nearby Iberian refugium, largely superseding the local B. bufo population, followed by an advance of B. bufo from the Balkans, with prongs north and south of the Alps, driving B. spinosus southwards. A pendulum moving hybrid zone, first northwards and then southwards, explains the wide areas of introgression at either side of the current position of the contact zones.
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Affiliation(s)
- Jan W Arntzen
- Naturalis Biodiversity Center, Leiden, The Netherlands
| | | | - Daniele Canestrelli
- Department of Ecological and Biological Science, Largo dell'Università s.n.c., Viterbo, Italy
| | - Iñigo Martínez-Solano
- Naturalis Biodiversity Center, Leiden, The Netherlands.,Evolution and Development Group, Department of Wetland Ecology, Doñana Biological Station, CSIC, Seville, Spain
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22
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Pörtner HO, Bock C, Mark FC. Oxygen- and capacity-limited thermal tolerance: bridging ecology and physiology. J Exp Biol 2017; 220:2685-2696. [DOI: 10.1242/jeb.134585] [Citation(s) in RCA: 289] [Impact Index Per Article: 41.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2016] [Accepted: 05/12/2017] [Indexed: 12/19/2022]
Abstract
ABSTRACT
Observations of climate impacts on ecosystems highlight the need for an understanding of organismal thermal ranges and their implications at the ecosystem level. Where changes in aquatic animal populations have been observed, the integrative concept of oxygen- and capacity-limited thermal tolerance (OCLTT) has successfully characterised the onset of thermal limits to performance and field abundance. The OCLTT concept addresses the molecular to whole-animal mechanisms that define thermal constraints on the capacity for oxygen supply to the organism in relation to oxygen demand. The resulting ‘total excess aerobic power budget’ supports an animal's performance (e.g. comprising motor activity, reproduction and growth) within an individual's thermal range. The aerobic power budget is often approximated through measurements of aerobic scope for activity (i.e. the maximum difference between resting and the highest exercise-induced rate of oxygen consumption), whereas most animals in the field rely on lower (i.e. routine) modes of activity. At thermal limits, OCLTT also integrates protective mechanisms that extend time-limited tolerance to temperature extremes – mechanisms such as chaperones, anaerobic metabolism and antioxidative defence. Here, we briefly summarise the OCLTT concept and update it by addressing the role of routine metabolism. We highlight potential pitfalls in applying the concept and discuss the variables measured that led to the development of OCLTT. We propose that OCLTT explains why thermal vulnerability is highest at the whole-animal level and lowest at the molecular level. We also discuss how OCLTT captures the thermal constraints on the evolution of aquatic animal life and supports an understanding of the benefits of transitioning from water to land.
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Affiliation(s)
- Hans-O. Pörtner
- Section of Integrative Ecophysiology, Biosciences, Alfred-Wegener-Institute, Bremerhaven D-27570, Germany
| | - Christian Bock
- Section of Integrative Ecophysiology, Biosciences, Alfred-Wegener-Institute, Bremerhaven D-27570, Germany
| | - Felix C. Mark
- Section of Integrative Ecophysiology, Biosciences, Alfred-Wegener-Institute, Bremerhaven D-27570, Germany
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23
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Leo E, Kunz KL, Schmidt M, Storch D, Pörtner HO, Mark FC. Mitochondrial acclimation potential to ocean acidification and warming of Polar cod ( Boreogadus saida) and Atlantic cod ( Gadus morhua). Front Zool 2017; 14:21. [PMID: 28416963 PMCID: PMC5391599 DOI: 10.1186/s12983-017-0205-1] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2017] [Accepted: 03/30/2017] [Indexed: 12/20/2022] Open
Abstract
Background Ocean acidification and warming are happening fast in the Arctic but little is known about the effects of ocean acidification and warming on the physiological performance and survival of Arctic fish. Results In this study we investigated the metabolic background of performance through analyses of cardiac mitochondrial function in response to control and elevated water temperatures and PCO2 of two gadoid fish species, Polar cod (Boreogadus saida), an endemic Arctic species, and Atlantic cod (Gadus morhua), which is a temperate to cold eurytherm and currently expanding into Arctic waters in the wake of ocean warming. We studied their responses to the above-mentioned drivers and their acclimation potential through analysing the cardiac mitochondrial function in permeabilised cardiac muscle fibres after 4 months of incubation at different temperatures (Polar cod: 0, 3, 6, 8 °C and Atlantic cod: 3, 8, 12, 16 °C), combined with exposure to present (400μatm) and year 2100 (1170μatm) levels of CO2. OXPHOS, proton leak and ATP production efficiency in Polar cod were similar in the groups acclimated at 400μatm and 1170μatm of CO2, while incubation at 8 °C evoked increased proton leak resulting in decreased ATP production efficiency and decreased Complex IV capacity. In contrast, OXPHOS of Atlantic cod increased with temperature without compromising the ATP production efficiency, whereas the combination of high temperature and high PCO2 depressed OXPHOS and ATP production efficiency. Conclusions Polar cod mitochondrial efficiency decreased at 8 °C while Atlantic cod mitochondria were more resilient to elevated temperature; however, this resilience was constrained by high PCO2. In line with its lower habitat temperature and higher degree of stenothermy, Polar cod has a lower acclimation potential to warming than Atlantic cod.
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Affiliation(s)
- Elettra Leo
- Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Integrative Ecophysiology, Am Handelshafen 12, D-27570 Bremerhaven, Germany.,University of Bremen, Fachbereich 2, NW 2/Leobener Strasse, D-28359 Bremen, Germany
| | - Kristina L Kunz
- Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Integrative Ecophysiology, Am Handelshafen 12, D-27570 Bremerhaven, Germany.,University of Bremen, Fachbereich 2, NW 2/Leobener Strasse, D-28359 Bremen, Germany.,Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Bentho-Pelagic Processes, Am Alten Hafen 26, D-27568 Bremerhaven, Germany
| | - Matthias Schmidt
- Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Integrative Ecophysiology, Am Handelshafen 12, D-27570 Bremerhaven, Germany.,University of Bremen, Fachbereich 2, NW 2/Leobener Strasse, D-28359 Bremen, Germany
| | - Daniela Storch
- Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Integrative Ecophysiology, Am Handelshafen 12, D-27570 Bremerhaven, Germany
| | - Hans-O Pörtner
- Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Integrative Ecophysiology, Am Handelshafen 12, D-27570 Bremerhaven, Germany.,University of Bremen, Fachbereich 2, NW 2/Leobener Strasse, D-28359 Bremen, Germany
| | - Felix C Mark
- Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Integrative Ecophysiology, Am Handelshafen 12, D-27570 Bremerhaven, Germany
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