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Xing Q, Yu H, Wang H, Ito SI, Yu W. Mesoscale eddies exert inverse latitudinal effects on global industrial squid fisheries. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 950:175211. [PMID: 39111423 DOI: 10.1016/j.scitotenv.2024.175211] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2024] [Revised: 07/21/2024] [Accepted: 07/31/2024] [Indexed: 08/10/2024]
Abstract
Squid species, as a burgeoning global food source, has garnered significant concerns due to expanding fisheries and little regulation. Elucidating the dynamics of squid fisheries and their biophysical coupling mechanisms is crucial for predicting spatiotemporal variations in squid fisheries and their sustainable management. Mesoscale eddies are discrete rotating oceanographic features that dominate local environmental variations and have been shown to modulate top predators. However, given controls of both predators and environmental factors, it remains unknown how eddies impact mid-trophic level species such as squids. Using satellite-based global squid fishery datasets, we showed an inverse latitudinal pattern of eddy-induced squid fisheries, where fishing activities are aggregated in (repelled from) cyclonic (anticyclonic) eddy cores in tropical waters and anticyclonic (cyclonic) eddy cores in temperate waters, and this pattern can be significantly enhanced with increasing eddy amplitude. Regarding solely the satellite-based global squid fisheries, eddy-induced environmental variations may generate a trade-off between food intake and energy expenditure, causing these oceanic squids to prefer cool cyclonic eddies in hot but food-limited waters, and warm anticyclonic eddies in nutritious but heat-limited waters. Given that eddy activity is projected to continuously enhance under global warming, our finding of eddy-driven bottom-up control for squid fisheries highlights an increasingly important hotspot for squid stock predictions and ecosystem-based ocean management in a changing climate.
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Affiliation(s)
- Qinwang Xing
- College of Marine Living Resource Sciences and Management, Shanghai Ocean University, Shanghai 201306, China; Institute of Marine Science and Technology, Shandong University, Qingdao 266237, China.
| | - Haiqing Yu
- Institute of Marine Science and Technology, Shandong University, Qingdao 266237, China.
| | - Hui Wang
- Institute of Marine Science and Technology, Shandong University, Qingdao 266237, China; National Marine Environmental Forecasting Center, Beijing 100086, China.
| | - Shin-Ichi Ito
- Atmosphere and Ocean Research Institute, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8564, Japan.
| | - Wei Yu
- College of Marine Living Resource Sciences and Management, Shanghai Ocean University, Shanghai 201306, China.
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2
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Kuzmenko NV, Galagudza MM. Hormonal basis of seasonal metabolic changes in mammalian species. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2024; 142:131-161. [PMID: 39059984 DOI: 10.1016/bs.apcsb.2024.02.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/28/2024]
Abstract
Seasonal changes in external conditions (photoperiod, meteorological conditions, diet) cause adaptive changes in both energy and substrate metabolism in the animals of mammalian species. In summer, long days and a rich diet contribute to relative elevation in the levels of thyroid hormones (TH), but warmer weather lowers their levels. In winter, short days and a poor diet inhibit TH synthesis, but low temperatures increase their secretion. In addition, the results of our meta-analyses revealed a significant role of atmospheric pressure in circannual fluctuations of metabolic parameters in humans. The changes in photoperiod are generally viewed as a major factor contributing to seasonal rhythm regulation However, numerous data show that season-dependent metabolic changes in mammals could be also accounted for by meteorological factors and diet.
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Affiliation(s)
- N V Kuzmenko
- Department for Experimental Physiology and Pharmacology, Almazov National Medical Research Centre, St. Petersburg, Russia.
| | - M M Galagudza
- Department for Experimental Physiology and Pharmacology, Almazov National Medical Research Centre, St. Petersburg, Russia
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3
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Penn JL, Deutsch C. Geographical and taxonomic patterns in aerobic traits of marine ectotherms. Philos Trans R Soc Lond B Biol Sci 2024; 379:20220487. [PMID: 38186276 PMCID: PMC10772604 DOI: 10.1098/rstb.2022.0487] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Accepted: 11/24/2023] [Indexed: 01/09/2024] Open
Abstract
The metabolism and hypoxia tolerance of marine ectotherms play key roles in limiting species geographical ranges, but underlying traits have only been directly measured for a small fraction of biodiversity. Here we diagnose and analyse spatial and phylogenetic patterns in hypoxia tolerance and its temperature sensitivity at ecologically active metabolic rates, by combining a model of organismal oxygen (O2) balance with global climate and biogeographic data for approximately 25 000 animal species from 13 phyla. Large-scale spatial trait patterns reveal that active hypoxia tolerance is greater and less temperature sensitive among tropical species compared to polar ones, consistent with sparse experimental data. Species energetic demands for activity vary less with temperature than resting costs, an inference confirmed by available rate measurements. Across the tree of life, closely related species share similar hypoxia traits, indicating that evolutionary history shapes physiological tolerances to O2 and temperature. Trait frequencies are highly conserved across phyla, suggesting the breadth of global aerobic conditions selects for convergent trait diversity. Our results support aerobic limitation as a constraint on marine habitat distributions and their responses to climate change and highlight the under-sampling of aerobic traits among species living in the ocean's tropical and polar oxythermal extremes. This article is part of the theme issue 'The evolutionary significance of variation in metabolic rates'.
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Affiliation(s)
- Justin L. Penn
- Department of Geosciences, Princeton University, Princeton 08544, NJ, USA
| | - Curtis Deutsch
- Department of Geosciences, Princeton University, Princeton 08544, NJ, USA
- High Meadows Environmental Institute, Princeton University, Princeton 08544, NJ, USA
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4
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Bandara RMWJ, Curchitser E, Pinsky ML. The importance of oxygen for explaining rapid shifts in a marine fish. GLOBAL CHANGE BIOLOGY 2024; 30:e17008. [PMID: 37943111 DOI: 10.1111/gcb.17008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 09/07/2023] [Accepted: 09/27/2023] [Indexed: 11/10/2023]
Abstract
Large-scale shifts in marine species biogeography have been a notable impact of climate change. An effective explanation of what drives these species shifts, as well as accurate predictions of where they might move, is crucial to effectively managing these natural resources and conserving biodiversity. While temperature has been implicated as a major driver of these shifts, physiological processes suggest that oxygen, prey, and other factors should also play important roles. We expanded upon previous temperature-based distribution models by testing whether oxygen, food web productivity, salinity, and scope for metabolic activity (the Metabolic Index) better explained the changing biogeography of Black Sea Bass (Centropristis striata) in the Northeast US. This species has been expanding further north over the past 15 years. We found that oxygen improved model performance beyond a simple consideration of temperature (ΔAIC = 799, ΔTSS = 0.015), with additional contributions from prey and salinity. However, the Metabolic Index did not substantially increase model performance relative to temperature and oxygen (ΔAIC = 0.63, ΔTSS = 0.0002). Marine species are sensitive to oxygen, and we encourage researchers to use ocean biogeochemical hindcast and forecast products to better understand marine biogeographic changes.
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Affiliation(s)
| | - Enrique Curchitser
- Department of Environmental Sciences, Rutgers University, New Brunswick, New Jersey, USA
| | - Malin L Pinsky
- Graduate Program in Ecology and Evolution, School of Environmental and Biological Sciences, Rutgers, The State University of New Jersey, New Brunswick, New Jersey, USA
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5
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Duncan MI, Micheli F, Boag TH, Marquez JA, Deres H, Deutsch CA, Sperling EA. Oxygen availability and body mass modulate ectotherm responses to ocean warming. Nat Commun 2023; 14:3811. [PMID: 37369654 DOI: 10.1038/s41467-023-39438-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Accepted: 06/13/2023] [Indexed: 06/29/2023] Open
Abstract
In an ocean that is rapidly warming and losing oxygen, accurate forecasting of species' responses must consider how this environmental change affects fundamental aspects of their physiology. Here, we develop an absolute metabolic index (ΦA) that quantifies how ocean temperature, dissolved oxygen and organismal mass interact to constrain the total oxygen budget an organism can use to fuel sustainable levels of aerobic metabolism. We calibrate species-specific parameters of ΦA with physiological measurements for red abalone (Haliotis rufescens) and purple urchin (Strongylocentrotus purpuratus). ΦA models highlight that the temperature where oxygen supply is greatest shifts cooler when water loses oxygen or organisms grow larger, providing a mechanistic explanation for observed thermal preference patterns. Viable habitat forecasts are disproportionally deleterious for red abalone, revealing how species-specific physiologies modulate the intensity of a common climate signal, captured in the newly developed ΦA framework.
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Affiliation(s)
- Murray I Duncan
- Earth and Planetary Science, Stanford University, Stanford, CA, USA.
- Oceans Department, Hopkins Marine Station, Stanford University, Pacific Grove, CA, USA.
- Department of Environment, University of Seychelles, Anse Royale, Seychelles.
- Blue Economy Research Institute, University of Seychelles, Anse Royale, Seychelles.
- Department of Ichthyology and Fisheries Science, Rhodes University, Makhanda, South Africa.
| | - Fiorenza Micheli
- Oceans Department, Hopkins Marine Station, Stanford University, Pacific Grove, CA, USA
- Stanford Center for Ocean Solutions, Stanford University, Pacific Grove, CA, USA
| | - Thomas H Boag
- Earth and Planetary Science, Stanford University, Stanford, CA, USA
- Department of Earth and Planetary Sciences, Yale University, New Haven, CT, 06511, USA
| | - J Andres Marquez
- Earth and Planetary Science, Stanford University, Stanford, CA, USA
| | - Hailey Deres
- Earth Systems, Stanford University, Stanford, CA, USA
| | - Curtis A Deutsch
- Department of Geosciences and the High Meadows Environmental Institute, Princeton, NJ, USA
| | - Erik A Sperling
- Earth and Planetary Science, Stanford University, Stanford, CA, USA
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6
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Somo DA, Chu K, Richards JG. Gill surface area allometry does not constrain the body mass scaling of maximum oxygen uptake rate in the tidepool sculpin, Oligocottus maculosus. J Comp Physiol B 2023:10.1007/s00360-023-01490-9. [PMID: 37149515 DOI: 10.1007/s00360-023-01490-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Revised: 03/03/2023] [Accepted: 04/14/2023] [Indexed: 05/08/2023]
Abstract
The gill oxygen limitation hypothesis (GOLH) suggests that hypometric scaling of metabolic rate in fishes is a consequence of oxygen supply constraints imposed by the mismatched growth rates of gill surface area (a two-dimensional surface) and body mass (a three-dimensional volume). GOLH may, therefore, explain the size-dependent spatial distribution of fish in temperature- and oxygen-variable environments through size-dependent respiratory capacity, but this question is unstudied. We tested GOLH in the tidepool sculpin, Oligocottus maculosus, a species in which body mass decreases with increasing temperature- and oxygen-variability in the intertidal, a pattern consistent with GOLH. We statistically evaluated support for GOLH versus distributed control of [Formula: see text] allometry by comparing scaling coefficients for gill surface area, standard and maximum [Formula: see text] ([Formula: see text],Standard and [Formula: see text],Max, respectively), ventricle mass, hematocrit, and metabolic enzyme activities in white muscle. To empirically evaluate whether there is a proximate constraint on oxygen supply capacity with increasing body mass, we measured [Formula: see text],Max across a range of Po2s from normoxia to Pcrit, calculated the regulation value (R), a measure of oxyregulatory capacity, and analyzed the R-body mass relationship. In contrast with GOLH, gill surface area scaling either matched or was more than sufficient to meet [Formula: see text] demands with increasing body mass and R did not change with body mass. Ventricle mass (b = 1.22) scaled similarly to [Formula: see text],Max (b = 1.18) suggesting a possible role for the heart in the scaling of [Formula: see text],Max. Together our results do not support GOLH as a mechanism structuring the distribution of O. maculosus and suggest distributed control of oxyregulatory capacity.
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Affiliation(s)
- Derek A Somo
- Department of Zoology, The University of British Columbia, Vancouver, BC, V6T 1Z4, Canada.
| | - Ken Chu
- Department of Zoology, The University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
| | - Jeffrey G Richards
- Department of Zoology, The University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
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7
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Trueblood LA, Onthank K, Bos N, Buller L, Coast A, Covrig M, Edwards E, Fratianni S, Gano M, Iwakoshi N, Kim E, Moss K, Personius C, Reynoso S, Springbett C. Bathyal octopus, Muusoctopus leioderma, living in a world of acid: First recordings of routine metabolic rate and critical oxygen partial pressures of a deep water species under elevated pCO2. Front Physiol 2022; 13:1039401. [DOI: 10.3389/fphys.2022.1039401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Accepted: 11/17/2022] [Indexed: 12/04/2022] Open
Abstract
Elevated atmospheric CO2 as a result of human activity is dissolving into the world’s oceans, driving a drop in pH, and making them more acidic. Here we present the first data on the impacts of ocean acidification on a bathyal species of octopus Muusoctopus leioderma. A recent discovery of a shallow living population in the Salish Sea, Washington United States allowed collection via SCUBA and maintenance in the lab. We exposed individual Muusoctopus leioderma to elevated CO2 pressure (pCO2) for 1 day and 7 days, measuring their routine metabolic rate (RMR), critical partial pressure (Pcrit), and oxygen supply capacity (α). At the time of this writing, we believe this is the first aerobic metabolic data recorded for a member of Muusoctopus. Our results showed that there was no change in either RMR, Pcrit or α at 1800 µatm compared to the 1,000 µatm of the habitat where this population was collected. The ability to maintain aerobic physiology at these relatively high levels is discussed and considered against phylogeny and life history.
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8
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Somo DA, Chu K, Richards JG. Aerobic scope falls to nil at Pcrit and anaerobic ATP production increases below Pcrit in the tidepool sculpin, Oligocottus maculosus. Biol Lett 2022; 18:20220342. [PMID: 36475421 PMCID: PMC9727657 DOI: 10.1098/rsbl.2022.0342] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The critical oxygen tension of whole-animal oxygen uptake rate, or Pcrit, has historically been defined as the oxygen partial pressure (PO2) at which aerobic scope falls to zero and further declines in PO2 require substrate-level phosphorylation to meet shortfalls in aerobic ATP production, thereby time-limiting survival. Despite the inclusion of aerobic scope and anaerobic ATP production in the definition, little effort has been made to verify that Pcrit measurements, the vast majority of which are obtained using respirometry in resting animals, actually reflect the predictions of zero aerobic scope and a transition to increasing reliance on anaerobic ATP production. To test these predictions, we compared aerobic scope and levels of whole-body lactate at oxygen partial pressures (PO2s) bracketing Pcrit obtained in resting fish during progressive hypoxia in the tidepool sculpin, Oligocottus maculosus. We found that aerobic scope falls to zero at Pcrit and, in resting fish exposed to PO2s < Pcrit, whole-body lactate accumulated pointing to an increased reliance on anaerobic ATP production. These results support the interpretation of Pcrit as a key oxygen threshold at which aerobic scope falls to nil and, below Pcrit, survival is time-limited based on anaerobic metabolic capacity.
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Affiliation(s)
- Derek A. Somo
- Department of Zoology, The University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z4
| | - Ken Chu
- Department of Zoology, The University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z4
| | - Jeffrey G. Richards
- Department of Zoology, The University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z4
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9
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Pardo SA, Dulvy NK. Body mass, temperature, and depth shape the maximum intrinsic rate of population increase in sharks and rays. Ecol Evol 2022; 12:e9441. [PMCID: PMC9618967 DOI: 10.1002/ece3.9441] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Accepted: 08/22/2022] [Indexed: 11/12/2022] Open
Abstract
An important challenge in ecology is to understand variation in species' maximum intrinsic rate of population increase, rmax, not least because rmax underpins our understanding of the limits of fishing, recovery potential, and ultimately extinction risk. Across many vertebrate species, terrestrial and aquatic, body mass and environmental temperature are important correlates of rmax. In sharks and rays, specifically, rmax is known to be lower in larger species, but also in deep sea ones. We use an information‐theoretic approach that accounts for phylogenetic relatedness to evaluate the relative importance of body mass, temperature, and depth on rmax. We show that both temperature and depth have separate effects on shark and ray rmax estimates, such that species living in deeper waters have lower rmax. Furthermore, temperature also correlates with changes in the mass scaling coefficient, suggesting that as body size increases, decreases in rmax are much steeper for species in warmer waters. These findings suggest that there are (as‐yet understood) depth‐related processes that limit the maximum rate at which populations can grow in deep‐sea sharks and rays. While the deep ocean is associated with colder temperatures, other factors that are independent of temperature, such as food availability and physiological constraints, may influence the low rmax observed in deep‐sea sharks and rays. Our study lays the foundation for predicting the intrinsic limit of fishing, recovery potential, and extinction risk species based on easily accessible environmental information such as temperature and depth, particularly for data‐poor species.
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Affiliation(s)
- Sebastián A. Pardo
- Earth to Ocean Research Group, Department of Biological SciencesSimon Fraser UniversityBurnabyBritish ColumbiaCanada,Ecology Action CentreHalifaxNova ScotiaCanada
| | - Nicholas K. Dulvy
- Earth to Ocean Research Group, Department of Biological SciencesSimon Fraser UniversityBurnabyBritish ColumbiaCanada
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10
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Verberk WCEP, Sandker JF, van de Pol ILE, Urbina MA, Wilson RW, McKenzie DJ, Leiva FP. Body mass and cell size shape the tolerance of fishes to low oxygen in a temperature-dependent manner. GLOBAL CHANGE BIOLOGY 2022; 28:5695-5707. [PMID: 35876025 DOI: 10.5281/zenodo.6123770] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 12/04/2021] [Revised: 03/11/2022] [Accepted: 05/22/2022] [Indexed: 05/20/2023]
Abstract
Aerobic metabolism generates 15-20 times more energy (ATP) than anaerobic metabolism, which is crucial in maintaining energy budgets in animals, fueling metabolism, activity, growth and reproduction. For ectothermic water-breathers such as fishes, low dissolved oxygen may limit oxygen uptake and hence aerobic metabolism. Here, we assess, within a phylogenetic context, how abiotic and biotic drivers explain the variation in hypoxia tolerance observed in fishes. To do so, we assembled a database of hypoxia tolerance, measured as critical oxygen tensions (Pcrit ) for 195 fish species. Overall, we found that hypoxia tolerance has a clear phylogenetic signal and is further modulated by temperature, body mass, cell size, salinity and metabolic rate. Marine fishes were more susceptible to hypoxia than freshwater fishes. This pattern is consistent with greater fluctuations in oxygen and temperature in freshwater habitats. Fishes with higher oxygen requirements (e.g. a high metabolic rate relative to body mass) also were more susceptible to hypoxia. We also found evidence that hypoxia and warming can act synergistically, as hypoxia tolerance was generally lower in warmer waters. However, we found significant interactions between temperature and the body and cell size of a fish. Constraints in oxygen uptake related to cellular surface area to volume ratios and effects of viscosity on the thickness of the boundary layers enveloping the gills could explain these thermal dependencies. The lower hypoxia tolerance in warmer waters was particularly pronounced for fishes with larger bodies and larger cell sizes. Previous studies have found a wide diversity in the direction and strength of relationships between Pcrit and body mass. By including interactions with temperature, our study may help resolve these divergent findings, explaining the size dependency of hypoxia tolerance in fish.
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Affiliation(s)
- Wilco C E P Verberk
- Department of Animal Ecology and Physiology, Radboud Institute for Biological and Environmental Sciences, Radboud University Nijmegen, Nijmegen, The Netherlands
| | - Jeroen F Sandker
- Department of Animal Ecology and Physiology, Radboud Institute for Biological and Environmental Sciences, Radboud University Nijmegen, Nijmegen, The Netherlands
| | - Iris L E van de Pol
- Department of Animal Ecology and Physiology, Radboud Institute for Biological and Environmental Sciences, Radboud University Nijmegen, Nijmegen, The Netherlands
| | - Mauricio A Urbina
- Departamento de Zoología, Facultad de Ciencias Naturales y Oceanográficas, Universidad de Concepción, Concepción, Chile
- Instituto Milenio de Oceanografía (IMO), Universidad de Concepción, Concepción, Chile
| | | | - David J McKenzie
- MARBEC, University of Montpellier, CNRS, IFREMER, IRD, Montpellier, France
| | - Félix P Leiva
- Department of Animal Ecology and Physiology, Radboud Institute for Biological and Environmental Sciences, Radboud University Nijmegen, Nijmegen, The Netherlands
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11
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Verberk WCEP, Sandker JF, van de Pol ILE, Urbina MA, Wilson RW, McKenzie DJ, Leiva FP. Body mass and cell size shape the tolerance of fishes to low oxygen in a temperature-dependent manner. GLOBAL CHANGE BIOLOGY 2022; 28:5695-5707. [PMID: 35876025 PMCID: PMC9542040 DOI: 10.1111/gcb.16319] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2021] [Revised: 03/11/2022] [Accepted: 05/22/2022] [Indexed: 05/04/2023]
Abstract
Aerobic metabolism generates 15-20 times more energy (ATP) than anaerobic metabolism, which is crucial in maintaining energy budgets in animals, fueling metabolism, activity, growth and reproduction. For ectothermic water-breathers such as fishes, low dissolved oxygen may limit oxygen uptake and hence aerobic metabolism. Here, we assess, within a phylogenetic context, how abiotic and biotic drivers explain the variation in hypoxia tolerance observed in fishes. To do so, we assembled a database of hypoxia tolerance, measured as critical oxygen tensions (Pcrit ) for 195 fish species. Overall, we found that hypoxia tolerance has a clear phylogenetic signal and is further modulated by temperature, body mass, cell size, salinity and metabolic rate. Marine fishes were more susceptible to hypoxia than freshwater fishes. This pattern is consistent with greater fluctuations in oxygen and temperature in freshwater habitats. Fishes with higher oxygen requirements (e.g. a high metabolic rate relative to body mass) also were more susceptible to hypoxia. We also found evidence that hypoxia and warming can act synergistically, as hypoxia tolerance was generally lower in warmer waters. However, we found significant interactions between temperature and the body and cell size of a fish. Constraints in oxygen uptake related to cellular surface area to volume ratios and effects of viscosity on the thickness of the boundary layers enveloping the gills could explain these thermal dependencies. The lower hypoxia tolerance in warmer waters was particularly pronounced for fishes with larger bodies and larger cell sizes. Previous studies have found a wide diversity in the direction and strength of relationships between Pcrit and body mass. By including interactions with temperature, our study may help resolve these divergent findings, explaining the size dependency of hypoxia tolerance in fish.
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Affiliation(s)
- Wilco C. E. P. Verberk
- Department of Animal Ecology and PhysiologyRadboud Institute for Biological and Environmental SciencesRadboud University NijmegenNijmegenThe Netherlands
| | - Jeroen F. Sandker
- Department of Animal Ecology and PhysiologyRadboud Institute for Biological and Environmental SciencesRadboud University NijmegenNijmegenThe Netherlands
| | - Iris L. E. van de Pol
- Department of Animal Ecology and PhysiologyRadboud Institute for Biological and Environmental SciencesRadboud University NijmegenNijmegenThe Netherlands
| | - Mauricio A. Urbina
- Departamento de Zoología, Facultad de Ciencias Naturales y OceanográficasUniversidad de ConcepciónConcepciónChile
- Instituto Milenio de Oceanografía (IMO)Universidad de ConcepciónConcepciónChile
| | | | - David J. McKenzie
- MARBEC, University of Montpellier, CNRS, IFREMER, IRDMontpellierFrance
| | - Félix P. Leiva
- Department of Animal Ecology and PhysiologyRadboud Institute for Biological and Environmental SciencesRadboud University NijmegenNijmegenThe Netherlands
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12
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Harrison JF, Biewener A, Bernhardt JR, Burger JR, Brown JH, Coto ZN, Duell ME, Lynch M, Moffett ER, Norin T, Pettersen AK, Smith FA, Somjee U, Traniello JFA, Williams TM. White Paper: An Integrated Perspective on the Causes of Hypometric Metabolic Scaling in Animals. Integr Comp Biol 2022; 62:icac136. [PMID: 35933126 PMCID: PMC9724154 DOI: 10.1093/icb/icac136] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2022] [Revised: 04/16/2022] [Accepted: 05/19/2022] [Indexed: 11/15/2022] Open
Abstract
Larger animals studied during ontogeny, across populations, or across species, usually have lower mass-specific metabolic rates than smaller animals (hypometric scaling). This pattern is usually observed regardless of physiological state (e.g. basal, resting, field, maximally-active). The scaling of metabolism is usually highly correlated with the scaling of many life history traits, behaviors, physiological variables, and cellular/molecular properties, making determination of the causation of this pattern challenging. For across-species comparisons of resting and locomoting animals (but less so for across populations or during ontogeny), the mechanisms at the physiological and cellular level are becoming clear. Lower mass-specific metabolic rates of larger species at rest are due to a) lower contents of expensive tissues (brains, liver, kidneys), and b) slower ion leak across membranes at least partially due to membrane composition, with lower ion pump ATPase activities. Lower mass-specific costs of larger species during locomotion are due to lower costs for lower-frequency muscle activity, with slower myosin and Ca++ ATPase activities, and likely more elastic energy storage. The evolutionary explanation(s) for hypometric scaling remain(s) highly controversial. One subset of evolutionary hypotheses relies on constraints on larger animals due to changes in geometry with size; for example, lower surface-to-volume ratios of exchange surfaces may constrain nutrient or heat exchange, or lower cross-sectional areas of muscles and tendons relative to body mass ratios would make larger animals more fragile without compensation. Another subset of hypotheses suggests that hypometric scaling arises from biotic interactions and correlated selection, with larger animals experiencing less selection for mass-specific growth or neurolocomotor performance. A additional third type of explanation comes from population genetics. Larger animals with their lower effective population sizes and subsequent less effective selection relative to drift may have more deleterious mutations, reducing maximal performance and metabolic rates. Resolving the evolutionary explanation for the hypometric scaling of metabolism and associated variables is a major challenge for organismal and evolutionary biology. To aid progress, we identify some variation in terminology use that has impeded cross-field conversations on scaling. We also suggest that promising directions for the field to move forward include: 1) studies examining the linkages between ontogenetic, population-level, and cross-species allometries, 2) studies linking scaling to ecological or phylogenetic context, 3) studies that consider multiple, possibly interacting hypotheses, and 4) obtaining better field data for metabolic rates and the life history correlates of metabolic rate such as lifespan, growth rate and reproduction.
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Affiliation(s)
- Jon F Harrison
- School of Life Sciences, Arizona State University, Tempe, AZ 85287-4501, USA
| | - Andrew Biewener
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA 02138, USA
| | - Joanna R Bernhardt
- Department of Zoology, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
- Yale Institute for Biospheric Studies, New Haven, CT 06520, USA
| | - Joseph R Burger
- Department of Biology, University of Kentucky, Lexington, KY 40506, USA
| | - James H Brown
- Center for Evolutionary and Theoretical Immunology, The University of New Mexico, Albuquerque, NM 87131, USA
| | - Zach N Coto
- Department of Biology, Boston University, Boston, MA 02215, USA
| | - Meghan E Duell
- Department of Biology, The University of Western Ontario, London, ON N6A 3K7, Canada
| | - Michael Lynch
- Biodesign Center for Mechanisms of Evolution, Arizona State University, Tempe, AZ 85281, USA
| | - Emma R Moffett
- Department of Ecology and Evolution, University of California, Irvine, CA 92697, USA
| | - Tommy Norin
- DTU Aqua | National Institute of Aquatic Resources, Technical University of Denmark, Anker Engelunds Vej 1 Bygning 101A, 2800 Kgs. Lyngby, Denmark
| | - Amanda K Pettersen
- School of Life and Environmental Sciences, The University of Sydney, Sydney, NSW 2006, Australia
| | - Felisa A Smith
- Department of Biology, University of New Mexico, Albuquerque, NM 87131, USA
| | - Ummat Somjee
- Smithsonian Tropical Research Institute, Panama City, Panama
| | | | - Terrie M Williams
- Division of Physical and Biological Sciences, University of California, Santa Cruz, CA 95064, USA
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13
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Telemeco RS, Gangloff EJ, Cordero GA, Rodgers EM, Aubret F. From performance curves to performance surfaces: Interactive effects of temperature and oxygen availability on aerobic and anaerobic performance in the common wall lizard. Funct Ecol 2022. [DOI: 10.1111/1365-2435.14147] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Rory S. Telemeco
- Department of Biology California State University Fresno Fresno CA USA
| | - Eric J. Gangloff
- Department of Biological Sciences Ohio Wesleyan University Delaware OH USA
| | - G. Antonio Cordero
- Centre for Ecology, Evolution and Environmental Changes, Department of Animal Biology University of Lisbon Lisbon Portugal
| | - Essie M. Rodgers
- School of Biological Sciences, University of Canterbury Christchurch New Zealand
| | - Fabien Aubret
- Station d’Ecologie Théorique et Expérimentale du CNRS – UPR 2001 Moulis France
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14
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Impact of warming on aquatic body sizes explained by metabolic scaling from microbes to macrofauna. Proc Natl Acad Sci U S A 2022; 119:e2201345119. [PMID: 35787059 PMCID: PMC9282389 DOI: 10.1073/pnas.2201345119] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Warming of the ocean is predicted to cause a reduction in the body sizes of marine animal species, but the biological basis for this prediction remains debated. We present a generalized mechanistic model of oxygen supply and demand that successfully reproduces the magnitude, variation, and temperature and body size dependence of body size responses to temperature change in laboratory experiments, supporting oxygen limitation as their underlying cause. When applied to accelerating future climate change scenarios, our results imply that the “temperature-size rule” will cause widely varying responses across the body size spectrum from microbes to macrofauna, impacting the function of size-structured marine food webs. Rising temperatures are associated with reduced body size in many marine species, but the biological cause and generality of the phenomenon is debated. We derive a predictive model for body size responses to temperature and oxygen (O2) changes based on thermal and geometric constraints on organismal O2 supply and demand across the size spectrum. The model reproduces three key aspects of the observed patterns of intergenerational size reductions measured in laboratory warming experiments of diverse aquatic ectotherms (i.e., the “temperature-size rule” [TSR]). First, the interspecific mean and variability of the TSR is predicted from species’ temperature sensitivities of hypoxia tolerance, whose nonlinearity with temperature also explains the second TSR pattern—its amplification as temperatures rise. Third, as body size increases across the tree of life, the impact of growth on O2 demand declines while its benefit to O2 supply rises, decreasing the size dependence of hypoxia tolerance and requiring larger animals to contract by a larger fraction to compensate for a thermally driven rise in metabolism. Together our results support O2 limitation as the mechanism underlying the TSR, and they provide a physiological basis for projecting ectotherm body size responses to climate change from microbes to macrofauna. For small species unable to rapidly migrate or evolve greater hypoxia tolerance, ocean warming and O2 loss in this century are projected to induce >20% reductions in body mass. Size reductions at higher trophic levels could be even stronger and more variable, compounding the direct impact of human harvesting on size-structured ocean food webs.
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15
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Collins M, Truebano M, Spicer JI. Consequences of thermal plasticity for hypoxic performance in coastal amphipods. MARINE ENVIRONMENTAL RESEARCH 2022; 177:105624. [PMID: 35436652 DOI: 10.1016/j.marenvres.2022.105624] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Revised: 04/07/2022] [Accepted: 04/09/2022] [Indexed: 05/20/2023]
Abstract
Physiological plasticity may confer an ability to deal with the effect of rapid climate change on aquatic ectotherms. However, plasticity induced by one stressor may only be adaptive in situ if it generates cross-tolerance to other stressors. Understanding the consequences of thermal acclimation on hypoxia thresholds is vital to understanding future climate-driven hypoxia. We tested if thermal acclimation benefits hypoxic performance in four closely-related amphipod species. The effects of thermal acclimation (7 days at 10 or 20 °C) on routine metabolic rate (RMR) and critical oxygen tensions (Pcrit) were determined at a standardised test temperature (20 °C). Gammarus chevreuxi and Echinogammarus marinus displayed increased Pcrit with acute warming but warm acclimation negated this increase. Pcrit of Gammarus duebeni was thermally insensitive. Gammarus zaddachi displayed increased Pcrit upon acute warming but little change via acclimation. Cross-tolerance between thermal plasticity and hypoxia may improve performance for some, but not all, species under future environmental change.
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Affiliation(s)
- Michael Collins
- Marine Biology and Ecology Research Centre, School of Biological and Marine Sciences, University of Plymouth, Plymouth, PL4 8AA, UK.
| | - Manuela Truebano
- Marine Biology and Ecology Research Centre, School of Biological and Marine Sciences, University of Plymouth, Plymouth, PL4 8AA, UK
| | - John I Spicer
- Marine Biology and Ecology Research Centre, School of Biological and Marine Sciences, University of Plymouth, Plymouth, PL4 8AA, UK
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16
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Howald S, Moyano M, Crespel A, Kuchenmüller LL, Cominassi L, Claireaux G, Peck MA, Mark FC. Effects of Ocean Acidification over successive generations decrease larval resilience to Ocean Acidification & Warming but juvenile European sea bass could benefit from higher temperatures in the NE Atlantic. J Exp Biol 2022; 225:275035. [PMID: 35417012 DOI: 10.1242/jeb.243802] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Accepted: 04/01/2022] [Indexed: 11/20/2022]
Abstract
European sea bass (Dicentrarchus labrax) is a large, economically important fish species with a long generation time whose long-term resilience to ocean acidification (OA) and warming (OW) is not clear. We incubated sea bass from Brittany (France) for two generations (>5 years in total) under ambient and predicted OA conditions (PCO2: 650 and 1700 µatm) crossed with ambient and predicted ocean OW conditions in F1 (temperature: 15-18°C and 20-23°C) to investigate the effects of climate change on larval and juvenile growth and metabolic rate. We found that in F1, OA as single stressor at ambient temperature did not affect larval or juvenile growth and OW increased developmental time and growth rates, but OAW decreased larval size at metamorphosis. Larval routine and juvenile standard metabolic rates were significantly lower in cold compared to warm conditioned fish and also lower in F0 compared to F1 fish. We did not find any effect of OA as a single stressor on metabolic rates. Juvenile PO2crit was not affected by OA or OAW in both generations. We discuss the potential underlying mechanisms resulting in the resilience of F0 and F1 larvae and juveniles to OA and in the beneficial effects of OW on F1 larval growth and metabolic rate, but on the other hand in the vulnerability of F1, but not F0 larvae to OAW. With regard to the ecological perspective, we conclude that recruitment of larvae and early juveniles to nursery areas might decrease under OAW conditions but individuals reaching juvenile phase might benefit from increased performance at higher temperatures.
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Affiliation(s)
- Sarah Howald
- Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Integrative Ecophysiology, Bremerhaven, Germany.,Institute of Marine Ecosystem and Fisheries Science, Center for Earth System Research and Sustainability (CEN), University of Hamburg, Germany
| | - Marta Moyano
- Institute of Marine Ecosystem and Fisheries Science, Center for Earth System Research and Sustainability (CEN), University of Hamburg, Germany.,Center for Coastal Research, University of Agder, Postbox 422, 4604 Kristiansand, Norway
| | - Amélie Crespel
- Ifremer, LEMAR (UMR 6539), Laboratory of Adaptation, and Nutrition of Fish, Centre Ifremer de Bretagne, Plouzané, France
| | - Luis L Kuchenmüller
- Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Integrative Ecophysiology, Bremerhaven, Germany
| | - Louise Cominassi
- Institute of Marine Ecosystem and Fisheries Science, Center for Earth System Research and Sustainability (CEN), University of Hamburg, Germany.,Institute of Arctic Biology, University of Alaska, Fairbanks, PO Box 757000, Fairbanks, AK 99775, USA
| | - Guy Claireaux
- Université de Bretagne Occidentale, LEMAR (UMR 6539), Brest, France.,Ifremer, LEMAR (UMR 6539), Laboratory of Adaptation, 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, Germany.,Coastal Systems (COS), Royal Netherlands Institute for Sea Research (NIOZ), Netherlands
| | - Felix C Mark
- Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Integrative Ecophysiology, Bremerhaven, Germany
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17
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Hvas M. Influence of photoperiod and protocol length on metabolic rate traits in ballan wrasse Labrus bergylta. JOURNAL OF FISH BIOLOGY 2022; 100:687-696. [PMID: 34928505 DOI: 10.1111/jfb.14981] [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: 10/18/2021] [Revised: 12/15/2021] [Accepted: 12/16/2021] [Indexed: 06/14/2023]
Abstract
In this study, ballan wrasse Labrus bergylta were subjected to either a conventional 1-day or an extended 5-day respirometry protocol. Additionally, in the 5-day protocol the fish were subjected to a 12 h light-dark cycle to assess the effects of photoperiods on metabolic rates (ṀO2 ). Diurnal patterns in routine and resting ṀO2 were not observed, suggesting that circadian rhythms in metabolism largely are driven by activity patterns rather than being of endogenous origin. Moreover, lack of a detectable circadian ṀO2 may be an adaptation to lower costs of living in ballan wrasse. Protocol length influenced standard metabolic rates (SMR) where estimates decreased by 13% and 17% when using 48 h and 5 days, respectively, compared to 24 h. The maximum metabolic rate (MMR) and the derived absolute aerobic scope (MMR-SMR) were unaffected by protocol length. However, factorial scopes (MMR/SMR) were reduced from 8.5 to 6.4 in the 5-day protocol, showing that factorial scopes are more sensitive to how SMR are obtained. The critical oxygen tension (Pcrit ) was reduced from 15% PO2 in the 1-day group to 11% PO2 in the 5-day group. However, ṀO2 in response to decreasing PO2 was similar, which together with a similar oxygen extraction coefficient, α (ṀO2 /PO2 ), suggested that the higher Pcrit in the 1-day group was an artefact of overestimating SMR. Finally, α was 12% lower at MMR compared to at Pcrit , which either means that MMR was underestimated in proportion to this difference or that α is not constant in the entire PO2 range. In summary, this study found that a conventional 1-day respirometry protocol may overestimate SMR and thereby alter the derived Pcrit and aerobic scope, while α is unaffected by protocol length. Moreover, alternating light conditions in the absence of other stressors did not influence ṀO2 in ballan wrasse.
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Affiliation(s)
- Malthe Hvas
- Animal Welfare Research Group, Institute of Marine Research, Matre, Norway
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18
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Burford B, Wild LA, Schwarz R, Chenoweth EM, Sreenivasan A, Elahi R, Carey N, Hoving HJT, Straley JM, Denny MW. Rapid range expansion of a marine ectotherm reveals the demographic and ecological consequences of short-term variability in seawater temperature and dissolved oxygen. Am Nat 2021; 199:523-550. [DOI: 10.1086/718575] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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19
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Bodensteiner BL, Gangloff EJ, Kouyoumdjian L, Muñoz MM, Aubret F. Thermal-metabolic phenotypes of the lizard Podarcis muralis differ across elevation, but converge in high-elevation hypoxia. J Exp Biol 2021; 224:273727. [PMID: 34761802 DOI: 10.1242/jeb.243660] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Accepted: 11/08/2021] [Indexed: 11/20/2022]
Abstract
In response to a warming climate, many montane species are shifting upslope to track the emergence of preferred temperatures. Characterizing patterns of variation in metabolic, physiological and thermal traits along an elevational gradient, and the plastic potential of these traits, is necessary to understand current and future responses to abiotic constraints at high elevations, including limited oxygen availability. We performed a transplant experiment with the upslope-colonizing common wall lizard (Podarcis muralis) in which we measured nine aspects of thermal physiology and aerobic capacity in lizards from replicate low- (400 m above sea level, ASL) and high-elevation (1700 m ASL) populations. We first measured traits at their elevation of origin and then transplanted half of each group to extreme high elevation (2900 m ASL; above the current elevational range limit of this species), where oxygen availability is reduced by ∼25% relative to sea level. After 3 weeks of acclimation, we again measured these traits in both the transplanted and control groups. The multivariate thermal-metabolic phenotypes of lizards originating from different elevations differed clearly when measured at the elevation of origin. For example, high-elevation lizards are more heat tolerant than their low-elevation counterparts (counter-gradient variation). Yet, these phenotypes converged after exposure to reduced oxygen availability at extreme high elevation, suggesting limited plastic responses under this novel constraint. Our results suggest that high-elevation populations are well suited to their oxygen environments, but that plasticity in the thermal-metabolic phenotype does not pre-adapt these populations to colonize more hypoxic environments at higher elevations.
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Affiliation(s)
- Brooke L Bodensteiner
- Department of Ecology and Evolutionary Biology, Yale University, 165 Prospect Street, New Haven, CT 06511, USA
| | - Eric J Gangloff
- Station d'Ecologie Théorique et Expérimentale du CNRS - UMR 5321, 09200 Moulis, France.,Department of Biological Sciences, Ohio Wesleyan University, Delaware, 43015 OH, USA
| | - Laura Kouyoumdjian
- Station d'Ecologie Théorique et Expérimentale du CNRS - UMR 5321, 09200 Moulis, France
| | - Martha M Muñoz
- Department of Ecology and Evolutionary Biology, Yale University, 165 Prospect Street, New Haven, CT 06511, USA
| | - Fabien Aubret
- Station d'Ecologie Théorique et Expérimentale du CNRS - UMR 5321, 09200 Moulis, France.,School of Molecular and Life Sciences, Curtin University, Bentley, WA 6102, Australia
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20
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Quantitative mismatch between empirical temperature-size rule slopes and predictions based on oxygen limitation. Sci Rep 2021; 11:23594. [PMID: 34880310 PMCID: PMC8654919 DOI: 10.1038/s41598-021-03051-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Accepted: 11/24/2021] [Indexed: 11/08/2022] Open
Abstract
In ectotherms, adult body size commonly declines with increasing environmental temperature, a pattern known as the temperature-size rule. One influential hypothesis explaining this observation is that the challenge of obtaining sufficient oxygen to support metabolism becomes greater with increasing body size, and more so at high temperatures. Yet, previous models based on this hypothesis do not account for phenotypic plasticity in the physiology of organisms that counteracts oxygen limitation at high temperature. Here, we model the predicted strength of the temperature-size response using estimates of how both the oxygen supply and demand is affected by temperature when allowing for phenotypic plasticity in the aquatic ectotherm Daphnia magna. Our predictions remain highly inconsistent with empirical temperature-size responses, with the prior being close to one order of magnitude stronger than the latter. These results fail to provide quantitative support for the hypothesis that oxygen limitation drives temperature-size clines in aquatic ectotherms. Future studies into the role of oxygen limitation should address how the strength of the temperature-size response may be shaped by evolution under fluctuating temperature regimes. Finally, our results caution against applying deterministic models based on the oxygen limitation hypothesis when predicting future changes in ectotherm size distributions under climate change.
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21
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Decreasing Phanerozoic extinction intensity as a consequence of Earth surface oxygenation and metazoan ecophysiology. Proc Natl Acad Sci U S A 2021; 118:2101900118. [PMID: 34607946 DOI: 10.1073/pnas.2101900118] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/26/2021] [Indexed: 11/18/2022] Open
Abstract
The decline in background extinction rates of marine animals through geologic time is an established but unexplained feature of the Phanerozoic fossil record. There is also growing consensus that the ocean and atmosphere did not become oxygenated to near-modern levels until the mid-Paleozoic, coinciding with the onset of generally lower extinction rates. Physiological theory provides us with a possible causal link between these two observations-predicting that the synergistic impacts of oxygen and temperature on aerobic respiration would have made marine animals more vulnerable to ocean warming events during periods of limited surface oxygenation. Here, we evaluate the hypothesis that changes in surface oxygenation exerted a first-order control on extinction rates through the Phanerozoic using a combined Earth system and ecophysiological modeling approach. We find that although continental configuration, the efficiency of the biological carbon pump in the ocean, and initial climate state all impact the magnitude of modeled biodiversity loss across simulated warming events, atmospheric oxygen is the dominant predictor of extinction vulnerability, with metabolic habitat viability and global ecophysiotype extinction exhibiting inflection points around 40% of present atmospheric oxygen. Given this is the broad upper limit for estimates of early Paleozoic oxygen levels, our results are consistent with the relative frequency of high-magnitude extinction events (particularly those not included in the canonical big five mass extinctions) early in the Phanerozoic being a direct consequence of limited early Paleozoic oxygenation and temperature-dependent hypoxia responses.
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22
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Seibel B, Andres A, Birk M, Shaw T, Timpe A, Welsh C. Response to 'Coming up for air'. J Exp Biol 2021; 224:272172. [PMID: 34522952 DOI: 10.1242/jeb.243148] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Accepted: 08/09/2021] [Indexed: 11/20/2022]
Affiliation(s)
- Brad Seibel
- University of South Florida, College of Marine Science, 830 1st St SE, St Petersburg, FL 33701, USA
| | - Alyssa Andres
- University of South Florida, College of Marine Science, 830 1st St SE, St Petersburg, FL 33701, USA
| | - Matthew Birk
- University of South Florida, College of Marine Science, 830 1st St SE, St Petersburg, FL 33701, USA
| | - Tracy Shaw
- University of South Florida, College of Marine Science, 830 1st St SE, St Petersburg, FL 33701, USA
| | - Alexander Timpe
- University of South Florida, College of Marine Science, 830 1st St SE, St Petersburg, FL 33701, USA
| | - Christina Welsh
- University of South Florida, College of Marine Science, 830 1st St SE, St Petersburg, FL 33701, USA
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23
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Bouyoucos IA, Trujillo JE, Weideli OC, Nakamura N, Mourier J, Planes S, Simpfendorfer CA, Rummer JL. Investigating links between thermal tolerance and oxygen supply capacity in shark neonates from a hyperoxic tropical environment. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 782:146854. [PMID: 33853007 DOI: 10.1016/j.scitotenv.2021.146854] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 03/09/2021] [Accepted: 03/26/2021] [Indexed: 06/12/2023]
Abstract
Temperature and oxygen limit the distribution of marine ectotherms. Haematological traits underlying blood-oxygen carrying capacity are thought to be correlated with thermal tolerance in certain fishes, and this relationship is hypothesised to be explained by oxygen supply capacity. We tested this hypothesis using reef shark neonates as experimental models because they live near their upper thermal limits and are physiologically sensitive to low oxygen conditions. We first described in situ associations between temperature and oxygen at the study site (Moorea, French Polynesia) and found that the habitats for reef shark neonates (Carcharhinus melanopterus and Negaprion acutidens) were hyperoxic at the maximum recorded temperatures. Next, we tested for in situ associations between thermal habitat characteristics and haematological traits of neonates. Contrary to predictions, we only demonstrated a negative association between haemoglobin concentration and maximum habitat temperatures in C. melanopterus. Next, we tested for ex situ associations between critical thermal maximum (CTMax) and haematological traits, but only demonstrated a negative association between haematocrit and CTMax in C. melanopterus. Finally, we measured critical oxygen tension (pcrit) ex situ and estimated its temperature sensitivity to predict oxygen-dependent values of CTMax. Estimated temperature sensitivity of pcrit was similar to reported values for sharks and skates, and predicted values for CTMax equalled maximum habitat temperatures. These data demonstrate unique associations between haematological traits and thermal tolerance in a reef shark that are likely not explained by oxygen supply capacity. However, a relationship between oxygen supply capacity and thermal tolerance remains to be demonstrated empirically.
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Affiliation(s)
- Ian A Bouyoucos
- Australian Research Council Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, Queensland 4811, Australia; PSL Research University, EPHE-UPVD-CNRS, USR 3278 CRIOBE, Université de Perpignan, 58 Avenue Paul Alduy, 66860 Perpignan Cedex, France.
| | - José E Trujillo
- Department of Marine Science, University of Otago, Dunedin 9016, New Zealand
| | - Ornella C Weideli
- PSL Research University, EPHE-UPVD-CNRS, USR 3278 CRIOBE, Université de Perpignan, 58 Avenue Paul Alduy, 66860 Perpignan Cedex, France
| | - Nao Nakamura
- PSL Research University, EPHE-UPVD-CNRS, USR 3278 CRIOBE, Université de Perpignan, 58 Avenue Paul Alduy, 66860 Perpignan Cedex, France
| | - Johann Mourier
- PSL Research University, EPHE-UPVD-CNRS, USR 3278 CRIOBE, Université de Perpignan, 58 Avenue Paul Alduy, 66860 Perpignan Cedex, France; Laboratoire d'Excellence "CORAIL", EPHE, PSL Research University, UPVD, CNRS, USR 3278 CRIOBE, Papetoai, Moorea, French Polynesia; Université de Corse Pasquale Paoli, UMS 3514 Plateforme Marine Stella Mare, 20620 Biguglia, France
| | - Serge Planes
- PSL Research University, EPHE-UPVD-CNRS, USR 3278 CRIOBE, Université de Perpignan, 58 Avenue Paul Alduy, 66860 Perpignan Cedex, France; Laboratoire d'Excellence "CORAIL", EPHE, PSL Research University, UPVD, CNRS, USR 3278 CRIOBE, Papetoai, Moorea, French Polynesia
| | - Colin A Simpfendorfer
- Centre for Sustainable Tropical Fisheries and Aquaculture & College of Science and Engineering, James Cook University, Townsville, Queensland 4811, Australia
| | - Jodie L Rummer
- Australian Research Council Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, Queensland 4811, Australia
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24
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Hypoxia Performance Curve: Assess a Whole-Organism Metabolic Shift from a Maximum Aerobic Capacity towards a Glycolytic Capacity in Fish. Metabolites 2021; 11:metabo11070447. [PMID: 34357341 PMCID: PMC8307916 DOI: 10.3390/metabo11070447] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Revised: 06/29/2021] [Accepted: 07/01/2021] [Indexed: 11/16/2022] Open
Abstract
The utility of measuring whole-animal performance to frame the metabolic response to environmental hypoxia is well established. Progressively reducing ambient oxygen (O2) will initially limit maximum metabolic rate as a result of a hypoxemic state and ultimately lead to a time-limited, tolerance state supported by substrate-level phosphorylation when the O2 supply can no longer meet basic needs (standard metabolic rate, SMR). The metabolic consequences of declining ambient O2 were conceptually framed for fishes initially by Fry's hypoxic performance curve, which characterizes the hypoxemic state and its consequences to absolute aerobic scope (AAS), and Hochachka's concept of scope for hypoxic survival, which characterizes time-limited life when SMR cannot be supported by O2 supply. Yet, despite these two conceptual frameworks, the toolbox to assess whole-animal metabolic performance remains rather limited. Here, we briefly review the ongoing debate concerning the need to standardize the most commonly used assessments of respiratory performance in hypoxic fishes, namely critical O2 (the ambient O2 level below which maintenance metabolism cannot be sustained) and the incipient lethal O2 (the ambient O2 level at which a fish loses the ability to maintain upright equilibrium), and then we advance the idea that the most useful addition to the toolbox will be the limiting-O2 concentration (LOC) performance curve. Using Fry & Hart's (1948) hypoxia performance curve concept, an LOC curve was subsequently developed as an eco-physiological framework by Neil et al. and derived for a group of fish during a progressive hypoxia trial by Claireaux and Lagardère (1999). In the present review, we show how only minor modifications to available respirometry tools and techniques are needed to generate an LOC curve for individual fish. This individual approach to the LOC curve determination then increases its statistical robustness and importantly opens up the possibility of examining individual variability. Moreover, if peak aerobic performance at a given ambient O2 level of each individual is expressed as a percentage of its AAS, the water dissolved O2 that supports 50% of the individual's AAS (DOAAS-50) can be interpolated much like the P50 for an O2 hemoglobin dissociation curve (when hemoglobin is 50% saturated with O2). Thus, critical O2, incipient lethal O2, DOAAS-50 and P50 and can be directly compared within and across species. While an LOC curve for individual fish represents a start to an ongoing need to seamlessly integrate aerobic to anaerobic capacity assessments in a single, multiplexed respirometry trial, we close with a comparative exploration of some of the known whole-organism anaerobic and aerobic capacity traits to examine for correlations among them and guide the next steps.
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25
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Esbaugh AJ, Ackerly KL, Dichiera AM, Negrete B. Is hypoxia vulnerability in fishes a by-product of maximum metabolic rate? J Exp Biol 2021; 224:269306. [PMID: 34184035 DOI: 10.1242/jeb.232520] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The metabolic index concept combines metabolic data and known thermal sensitivities to estimate the factorial aerobic scope of animals in different habitats, which is valuable for understanding the metabolic demands that constrain species' geographical distributions. An important assumption of this concept is that the O2 supply capacity (which is equivalent to the rate of oxygen consumption divided by the environmental partial pressure of oxygen: ) is constant at O2 tensions above the critical O2 threshold (i.e. the where O2 uptake can no longer meet metabolic demand). This has led to the notion that hypoxia vulnerability is not a selected trait, but a by-product of selection on maximum metabolic rate. In this Commentary, we explore whether this fundamental assumption is supported among fishes. We provide evidence that O2 supply capacity is not constant in all fishes, with some species exhibiting an elevated O2 supply capacity in hypoxic environments. We further discuss the divergent selective pressures on hypoxia- and exercise-based cardiorespiratory adaptations in fishes, while also considering the implications of a hypoxia-optimized O2 supply capacity for the metabolic index concept.
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Affiliation(s)
- Andrew J Esbaugh
- University of Texas at Austin, Marine Science Institute, Port Aransas, TX 78373, USA
| | - Kerri L Ackerly
- University of Texas at Austin, Marine Science Institute, Port Aransas, TX 78373, USA
| | - Angelina M Dichiera
- University of Texas at Austin, Marine Science Institute, Port Aransas, TX 78373, USA
| | - Benjamin Negrete
- University of Texas at Austin, Marine Science Institute, Port Aransas, TX 78373, USA
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26
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Seibel BA, Andres A, Birk MA, Burns AL, Shaw CT, Timpe AW, Welsh CJ. Oxygen supply capacity breathes new life into critical oxygen partial pressure (Pcrit). J Exp Biol 2021; 224:jeb.242210. [PMID: 33692079 DOI: 10.1242/jeb.242210] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Accepted: 03/01/2021] [Indexed: 12/11/2022]
Abstract
The critical oxygen partial pressure (Pcrit), typically defined as the PO2 below which an animal's metabolic rate (MR) is unsustainable, is widely interpreted as a measure of hypoxia tolerance. Here, Pcrit is defined as the PO2 at which physiological oxygen supply (α0) reaches its maximum capacity (α; µmol O2 g-1 h-1 kPa-1). α is a species- and temperature-specific constant describing the oxygen dependency of the maximum metabolic rate (MMR=PO2×α) or, equivalently, the MR dependence of Pcrit (Pcrit=MR/α). We describe the α-method, in which the MR is monitored as oxygen declines and, for each measurement period, is divided by the corresponding PO2 to provide the concurrent oxygen supply (α0=MR/PO2). The highest α0 value (or, more conservatively, the mean of the three highest values) is designated as α. The same value of α is reached at Pcrit for any MR regardless of previous or subsequent metabolic activity. The MR need not be constant (regulated), standardized or exhibit a clear breakpoint at Pcrit for accurate determination of α. The α-method has several advantages over Pcrit determination and non-linear analyses, including: (1) less ambiguity and greater accuracy, (2) fewer constraints in respirometry methodology and analysis, and (3) greater predictive power and ecological and physiological insight. Across the species evaluated here, α values are correlated with MR, but not Pcrit. Rather than an index of hypoxia tolerance, Pcrit is a reflection of α, which evolves to support maximum energy demands and aerobic scope at the prevailing temperature and oxygen level.
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Affiliation(s)
- Brad A Seibel
- College of Marine Science, University of South Florida, St Petersburg, FL 33701, USA
| | - Alyssa Andres
- College of Marine Science, University of South Florida, St Petersburg, FL 33701, USA
| | - Matthew A Birk
- College of Marine Science, University of South Florida, St Petersburg, FL 33701, USA
| | - Alexandra L Burns
- College of Marine Science, University of South Florida, St Petersburg, FL 33701, USA
| | - C Tracy Shaw
- College of Marine Science, University of South Florida, St Petersburg, FL 33701, USA
| | - Alexander W Timpe
- College of Marine Science, University of South Florida, St Petersburg, FL 33701, USA
| | - Christina J Welsh
- College of Marine Science, University of South Florida, St Petersburg, FL 33701, USA
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27
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Abstract
Less than a quarter of ocean deoxygenation that will ultimately be caused by historical CO2 emissions is already realized, according to millennial-scale model simulations that assume zero CO2 emissions from year 2021 onwards. About 80% of the committed oxygen loss occurs below 2000 m depth, where a more sluggish overturning circulation will increase water residence times and accumulation of respiratory oxygen demand. According to the model results, the deep ocean will thereby lose more than 10% of its pre-industrial oxygen content even if CO2 emissions and thus global warming were stopped today. In the surface layer, however, the ongoing deoxygenation will largely stop once CO2 emissions are stopped. Accounting for the joint effects of committed oxygen loss and ocean warming, metabolic viability representative for marine animals declines by up to 25% over large regions of the deep ocean, posing an unavoidable escalation of anthropogenic pressure on deep-ocean ecosystems. Ocean warming and changing circulation as a result of climate change are driving down oxygen levels and threatening ecosystems. Here the author shows that though immediate cessation of anthropogenic CO2 emissions would halt upper ocean oxygen loss, it would continue in the deep ocean for 100 s of years.
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Pörtner HO. Climate impacts on organisms, ecosystems and human societies: integrating OCLTT into a wider context. J Exp Biol 2021; 224:224/Suppl_1/jeb238360. [PMID: 33627467 DOI: 10.1242/jeb.238360] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Physiological studies contribute to a cause and effect understanding of ecological patterns under climate change and identify the scope and limits of adaptation. Across most habitats, this requires analyzing organism responses to warming, which can be modified by other drivers such as acidification and oxygen loss in aquatic environments or excess humidity or drought on land. Experimental findings support the hypothesis that the width and temperature range of thermal performance curves relate to biogeographical range. Current warming causes range shifts, hypothesized to include constraints in aerobic power budget which in turn are elicited by limitations in oxygen supply capacity in relation to demand. Different metabolic scopes involved may set the borders of both the fundamental niche (at standard metabolic rate) and the realized niche (at routine rate). Relative scopes for aerobic performance also set the capacity of species to interact with others at the ecosystem level. Niche limits and widths are shifting and probably interdependent across life stages, with young adults being least thermally vulnerable. The principles of thermal tolerance and performance may also apply to endotherms including humans, their habitat and human society. Overall, phylogenetically based comparisons would need to consider the life cycle of species as well as organism functional properties across climate zones and time scales. This Review concludes with a perspective on how mechanism-based understanding allows scrutinizing often simplified modeling approaches projecting future climate impacts and risks for aquatic and terrestrial ecosystems. It also emphasizes the usefulness of a consensus-building process among experimentalists for better recognition in the climate debate.
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Affiliation(s)
- Hans-O Pörtner
- Integrative Ecophysiology section, Alfred Wegener Institute, Helmholtz Center for Marine and Polar Research, 27570 Bremetrhaven, Germany
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29
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Collins M, Truebano M, Verberk WCEP, Spicer JI. Do aquatic ectotherms perform better under hypoxia after warm acclimation? J Exp Biol 2021; 224:224/3/jeb232512. [PMID: 33542094 DOI: 10.1242/jeb.232512] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Aquatic animals increasingly encounter environmental hypoxia due to climate-related warming and/or eutrophication. Although acute warming typically reduces performance under hypoxia, the ability of organisms to modulate hypoxic performance via thermal acclimation is less understood. Here, we review the literature and ask whether hypoxic performance of aquatic ectotherms improves following warm acclimation. Interpretation of thermal acclimation effects is limited by reliance on data from experiments that are not designed to directly test for beneficial or detrimental effects on hypoxic performance. Most studies have tested hypoxic responses exclusively at test temperatures matching organisms' acclimation temperatures, precluding the possibility of distinguishing between acclimation and acute thermal effects. Only a few studies have applied appropriate methodology to identify beneficial thermal acclimation effects on hypoxic performance, i.e. acclimation to different temperatures prior to determining hypoxic responses at standardised test temperatures. These studies reveal that acute warming predominantly impairs hypoxic performance, whereas warm acclimation tends to be either beneficial or have no effect. If this generalises, we predict that warm-acclimated individuals in some species should outperform non-acclimated individuals under hypoxia. However, acclimation seems to only partially offset acute warming effects; therefore, aquatic ectotherms will probably display overall reduced hypoxic performance in the long term. Drawing on the appropriate methodology, future studies can quantify the ability of organisms to modulate hypoxic performance via (reversible) thermal acclimation and unravel the underlying mechanisms. Testing whether developmental acclimation and multigenerational effects allow for a more complete compensation is essential to allow us to predict species' resilience to chronically warmer, hypoxic environments.
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Affiliation(s)
- Michael Collins
- Marine Biology and Ecology Research Centre, Plymouth University, Drake Circus, PL4 8AA, UK
| | - Manuela Truebano
- Marine Biology and Ecology Research Centre, Plymouth University, Drake Circus, PL4 8AA, UK
| | - Wilco C E P Verberk
- Department of Animal Ecology and Physiology, Institute for Water and Wetland Research, Radboud University, 6500 GL Nijmegen, The Netherlands
| | - John I Spicer
- Marine Biology and Ecology Research Centre, Plymouth University, Drake Circus, PL4 8AA, UK
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30
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Verberk WC, Atkinson D, Hoefnagel KN, Hirst AG, Horne CR, Siepel H. Shrinking body sizes in response to warming: explanations for the temperature-size rule with special emphasis on the role of oxygen. Biol Rev Camb Philos Soc 2021; 96:247-268. [PMID: 32959989 PMCID: PMC7821163 DOI: 10.1111/brv.12653] [Citation(s) in RCA: 102] [Impact Index Per Article: 34.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Revised: 08/28/2020] [Accepted: 08/28/2020] [Indexed: 01/04/2023]
Abstract
Body size is central to ecology at levels ranging from organismal fecundity to the functioning of communities and ecosystems. Understanding temperature-induced variations in body size is therefore of fundamental and applied interest, yet thermal responses of body size remain poorly understood. Temperature-size (T-S) responses tend to be negative (e.g. smaller body size at maturity when reared under warmer conditions), which has been termed the temperature-size rule (TSR). Explanations emphasize either physiological mechanisms (e.g. limitation of oxygen or other resources and temperature-dependent resource allocation) or the adaptive value of either a large body size (e.g. to increase fecundity) or a short development time (e.g. in response to increased mortality in warm conditions). Oxygen limitation could act as a proximate factor, but we suggest it more likely constitutes a selective pressure to reduce body size in the warm: risks of oxygen limitation will be reduced as a consequence of evolution eliminating genotypes more prone to oxygen limitation. Thus, T-S responses can be explained by the 'Ghost of Oxygen-limitation Past', whereby the resulting (evolved) T-S responses safeguard sufficient oxygen provisioning under warmer conditions, reflecting the balance between oxygen supply and demands experienced by ancestors. T-S responses vary considerably across species, but some of this variation is predictable. Body-size reductions with warming are stronger in aquatic taxa than in terrestrial taxa. We discuss whether larger aquatic taxa may especially face greater risks of oxygen limitation as they grow, which may be manifested at the cellular level, the level of the gills and the whole-organism level. In contrast to aquatic species, terrestrial ectotherms may be less prone to oxygen limitation and prioritize early maturity over large size, likely because overwintering is more challenging, with concomitant stronger end-of season time constraints. Mechanisms related to time constraints and oxygen limitation are not mutually exclusive explanations for the TSR. Rather, these and other mechanisms may operate in tandem. But their relative importance may vary depending on the ecology and physiology of the species in question, explaining not only the general tendency of negative T-S responses but also variation in T-S responses among animals differing in mode of respiration (e.g. water breathers versus air breathers), genome size, voltinism and thermally associated behaviour (e.g. heliotherms).
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Affiliation(s)
- Wilco C.E.P. Verberk
- Department of Animal Ecology and Physiology, Institute for Water and Wetland ResearchRadboud UniversityHeyendaalseweg 1356525 AJNijmegenThe Netherlands
| | - David Atkinson
- Department of Evolution, Ecology and BehaviourUniversity of LiverpoolLiverpoolL69 7ZBU.K.
| | - K. Natan Hoefnagel
- Department of Animal Ecology and Physiology, Institute for Water and Wetland ResearchRadboud UniversityHeyendaalseweg 1356525 AJNijmegenThe Netherlands
- Faculty of Science and Engineering, Ocean Ecosystems — Energy and Sustainability Research Institute GroningenUniversity of GroningenNijenborgh 79747 AGGroningenThe Netherlands
| | - Andrew G. Hirst
- School of Environmental SciencesUniversity of LiverpoolLiverpoolL69 3GPU.K.
- Centre for Ocean Life, DTU AquaTechnical University of DenmarkLyngbyDenmark
| | - Curtis R. Horne
- School of Environmental SciencesUniversity of LiverpoolLiverpoolL69 3GPU.K.
| | - Henk Siepel
- Department of Animal Ecology and Physiology, Institute for Water and Wetland ResearchRadboud UniversityHeyendaalseweg 1356525 AJNijmegenThe Netherlands
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31
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Hermaniuk A, van de Pol ILE, Verberk WCEP. Are acute and acclimated thermal effects on metabolic rate modulated by cell size? A comparison between diploid and triploid zebrafish larvae. J Exp Biol 2021; 224:jeb227124. [PMID: 33257437 DOI: 10.1242/jeb.227124] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Accepted: 11/19/2020] [Indexed: 12/13/2022]
Abstract
Being composed of small cells may carry energetic costs related to maintaining ionic gradients across cell membranes as well as benefits related to diffusive oxygen uptake. Here, we test the hypothesis that these costs and benefits of cell size in ectotherms are temperature dependent. To study the consequences of cell size for whole-organism metabolic rate, we compared diploid and triploid zebrafish larvae differing in cell size. A fully factorial design was applied combining three different rearing and test temperatures that allowed us to distinguish acute from acclimated thermal effects. Individual oxygen consumption rates of diploid and triploid larvae across declining levels of oxygen availability were measured. We found that both acute and acclimated thermal effects affected the metabolic response. In comparison with triploids, diploids responded more strongly to acute temperatures, especially when reared at the highest temperature. These observations support the hypothesis that animals composed of smaller cells (i.e. diploids) are less vulnerable to oxygen limitation in warm aquatic habitats. Furthermore, we found slightly improved hypoxia tolerance in diploids. By contrast, warm-reared triploids had higher metabolic rates when they were tested at acute cold temperature, suggesting that being composed of larger cells may provide metabolic advantages in the cold. We offer two mechanisms as a potential explanation of this result, related to homeoviscous adaptation of membrane function and the mitigation of developmental noise. Our results suggest that being composed of larger cells provides metabolic advantages in cold water, while being composed of smaller cells provides metabolic advantages in warm water.
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Affiliation(s)
- Adam Hermaniuk
- Department of Evolutionary and Physiological Ecology, Faculty of Biology, University of Białystok, Ciołkowskiego 1J, 15-245 Białystok, Poland
| | - Iris L E van de Pol
- Department of Animal Ecology and Physiology, Institute for Water and Wetland Research, Radboud University, 6525 AJ Nijmegen, The Netherlands
| | - Wilco C E P Verberk
- Department of Animal Ecology and Physiology, Institute for Water and Wetland Research, Radboud University, 6525 AJ Nijmegen, The Netherlands
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32
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Oxygen limitation may affect the temperature and size dependence of metabolism in aquatic ectotherms. Proc Natl Acad Sci U S A 2020; 117:31963-31968. [PMID: 33257544 PMCID: PMC7749359 DOI: 10.1073/pnas.2003292117] [Citation(s) in RCA: 73] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Organismal responses to climate change are mediated through its effects on physiology and metabolism. In aquatic environments, both water temperature and oxygen availability may modulate these responses by altering the aerobic metabolism fueling physiological performance. However, ecological models aimed at predicting how environmental factors shape aerobic metabolism disregard the role of oxygen supply. Here, we expand on these models by explicitly incorporating oxygen supply. Our results show that warmer water increases oxygen demand relative to supply, and the resulting reduction in aerobic scope appears to be stronger in larger individuals. Smaller aerobic scopes in warming water imply that climate change will reduce energy budgets needed to support the activities of aquatic animals and their physiological performance in the future. Both oxygen and temperature are fundamental factors determining metabolic performance, fitness, ecological niches, and responses of many aquatic organisms to climate change. Despite the importance of physical and physiological constraints on oxygen supply affecting aerobic metabolism of aquatic ectotherms, ecological theories such as the metabolic theory of ecology have focused on the effects of temperature rather than oxygen. This gap currently impedes mechanistic models from accurately predicting metabolic rates (i.e., oxygen consumption rates) of aquatic organisms and restricts predictions to resting metabolism, which is less affected by oxygen limitation. Here, we expand on models of metabolic scaling by accounting for the role of oxygen availability and temperature on both resting and active metabolic rates. Our model predicts that oxygen limitation is more likely to constrain metabolism in larger, warmer, and active fish. Consequently, active metabolic rates are less responsive to temperature than are resting metabolic rates, and metabolism scales to body size with a smaller exponent whenever temperatures or activity levels are higher. Results from a metaanalysis of fish metabolic rates are consistent with our model predictions. The observed interactive effects of temperature, oxygen availability, and body size predict that global warming will limit the aerobic scope of aquatic ectotherms and may place a greater metabolic burden on larger individuals, impairing their physiological performance in the future. Our model reconciles the metabolic theory with empirical observations of oxygen limitation and provides a formal, quantitative framework for predicting both resting and active metabolic rate and hence aerobic scope of aquatic ectotherms.
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33
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Claunch NM, Nix E, Royal AE, Burgos LP, Corn M, DuBois PM, Ivey KN, King EC, Rucker KA, Shea TK, Stepanek J, Vansdadia S, Taylor EN. Body size impacts critical thermal maximum measurements in lizards. JOURNAL OF EXPERIMENTAL ZOOLOGY PART 2020; 335:96-107. [PMID: 32851814 DOI: 10.1002/jez.2410] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 08/10/2020] [Accepted: 08/13/2020] [Indexed: 12/18/2022]
Abstract
Understanding the mechanisms behind critical thermal maxima (CTmax; the high body temperature at which neuromuscular coordination is lost) of organisms is central to understanding ectotherm thermal tolerance. Body size is an often overlooked variable that may affect interpretation of CTmax, and consequently, how CTmax is used to evaluate mechanistic hypotheses of thermal tolerance. We tested the hypothesis that body size affects CTmax and its interpretation in two experimental contexts. First, in four Sceloporus species, we examined how inter- and intraspecific variation in body size affected CTmax at normoxic and experimentally induced hypoxic conditions, and cloacal heating rate under normoxic conditions. Negative relationships between body size and CTmax were exaggerated in larger species, and hypoxia-related reductions in CTmax were unaffected by body size. Smaller individuals had faster cloacal heating rates and higher CTmax, and variation in cloacal heating rate affected CTmax in the largest species. Second, we examined how body size interacted with the location of body temperature measurements (i.e., cloaca vs. brain) in Sceloporus occidentalis, then compared this in living and deceased lizards. Brain temperatures were consistently lower than cloacal temperatures. Smaller lizards had larger brain-cloacal temperature differences than larger lizards, due to a slower cloacal heating rate in large lizards. Both live and dead lizards had lower brain than cloacal temperatures, suggesting living lizards do not actively maintain lower brain temperatures when they cannot pant. Thermal inertia influences CTmax data in complex ways, and body size should therefore be considered in studies involving CTmax data on species with variable sizes.
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Affiliation(s)
- Natalie M Claunch
- Biological Sciences, California Polytechnic State University, San Luis Obispo, California
| | - Emmeleia Nix
- Biological Sciences, California Polytechnic State University, San Luis Obispo, California
| | - Averil E Royal
- Biological Sciences, California Polytechnic State University, San Luis Obispo, California
| | - Luis P Burgos
- Biological Sciences, California Polytechnic State University, San Luis Obispo, California
| | - Megan Corn
- Biological Sciences, California Polytechnic State University, San Luis Obispo, California
| | - P Mason DuBois
- Biological Sciences, California Polytechnic State University, San Luis Obispo, California
| | - Kathleen N Ivey
- Biological Sciences, California Polytechnic State University, San Luis Obispo, California
| | - Elina C King
- Biological Sciences, California Polytechnic State University, San Luis Obispo, California
| | - Kiley A Rucker
- Biological Sciences, California Polytechnic State University, San Luis Obispo, California
| | - Tanner K Shea
- Biological Sciences, California Polytechnic State University, San Luis Obispo, California
| | - John Stepanek
- Biological Sciences, California Polytechnic State University, San Luis Obispo, California
| | - Sunny Vansdadia
- Biological Sciences, California Polytechnic State University, San Luis Obispo, California
| | - Emily N Taylor
- Biological Sciences, California Polytechnic State University, San Luis Obispo, California
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34
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Reemeyer JE, Rees BB. Plasticity, repeatability and phenotypic correlations of aerobic metabolic traits in a small estuarine fish. J Exp Biol 2020; 223:jeb228098. [PMID: 32587069 DOI: 10.1242/jeb.228098] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Accepted: 06/10/2020] [Indexed: 12/14/2022]
Abstract
Standard metabolic rate (SMR), maximum metabolic rate (MMR), absolute aerobic scope (AAS) and critical oxygen tension (Pcrit) were determined for the Gulf killifish, Fundulus grandis, an ecologically dominant estuarine fish, acclimated to lowered salinity, elevated temperature and lowered oxygen concentration. Acclimation to low salinity resulted in a small, but significant, elevation of Pcrit (suggesting lower tolerance of hypoxia); acclimation to elevated temperature increased SMR, MMR, AAS and Pcrit; acclimation to low oxygen led to a small increase in SMR, but substantial decreases in MMR, AAS and Pcrit Variation in these metabolic traits among individuals was consistent and repeatable when measured during multiple control exposures over 7 months. Trait repeatability was unaffected by acclimation condition, suggesting that repeatability of these traits is not context dependent. There were significant phenotypic correlations between specific metabolic traits: SMR was positively correlated with MMR and Pcrit; MMR was positively correlated with AAS; and AAS was negatively correlated with Pcrit In general, within-individual variation contributed more than among-individual variation to these phenotypic correlations. The effects of acclimation on these traits demonstrate that aerobic metabolism is plastic and influenced by the conditions experienced by these fish in the dynamic habitats in which they occur; however, the repeatability of these traits and the correlations among them suggest that these traits change in ways that maintain the rank order of performance among individuals across a range of environmental variation.
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Affiliation(s)
- Jessica E Reemeyer
- University of New Orleans, Department of Biological Sciences, 2000 Lakeshore Drive, New Orleans, LA 70148, USA
| | - Bernard B Rees
- University of New Orleans, Department of Biological Sciences, 2000 Lakeshore Drive, New Orleans, LA 70148, USA
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35
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Duncan MI, James NC, Potts WM, Bates AE. Different drivers, common mechanism; the distribution of a reef fish is restricted by local-scale oxygen and temperature constraints on aerobic metabolism. CONSERVATION PHYSIOLOGY 2020; 8:coaa090. [PMID: 33654546 PMCID: PMC7904075 DOI: 10.1093/conphys/coaa090] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 07/14/2020] [Accepted: 10/03/2020] [Indexed: 05/02/2023]
Abstract
The distributions of ectothermic marine organisms are limited to temperature ranges and oxygen conditions that support aerobic respiration, quantified within the metabolic index (ϕ) as the ratio of oxygen supply to metabolic oxygen demand. However, the utility of ϕ at local scales and across heterogenous environments is unknown; yet, these scales are often where actionable management decisions are made. Here, we test if ϕ can delimit the entire distribution of marine organisms when calibrated across an appropriate temperature range and at local scales (~10 km) using the endemic reef fish, Chrysoblephus laticeps, which is found in the highly heterogenous temperature and oxygen environment along the South African coastal zone, as a model species. In laboratory experiments, we find a bidirectional (at 12°C) hypoxia tolerance response across the temperature range tested (8 to 24°C), permitting a piecewise calibration of ϕ. We then project this calibrated ϕ model through temperature and oxygen data from a high spatial resolution (11 to 13 km) ocean model for the periods 2005 to 2009 and 2095 to 2099 to quantify various magnitudes of ϕ across space and time paired with complementary C. laticeps occurrence points. Using random forest species distribution models, we quantify a critical ϕ value of 2.78 below which C. laticeps cannot persist and predict current and future distributions of C. laticeps in line with already observed distribution shifts of other South African marine species. Overall, we find that C. laticeps' distribution is limited by increasing temperatures towards its warm edge but by low oxygen availability towards its cool edge, which is captured within ϕ at fine scales and across heterogenous oxygen and temperature combinations. Our results support the application of ϕ for generating local- and regional-scale predictions of climate change effects on organisms that can inform local conservation management decisions.
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Affiliation(s)
- Murray I Duncan
- Department of Ichthyology and Fisheries Science, Rhodes University, Prince Alfred street, Makhanda, 6140, South Africa
- South African Institute for Aquatic Biodiversity, 11 Somerset street, Makhanda, 6139, South Africa
- Corresponding author: Department of Geological Sciences, Stanford University, Stanford, 94305, USA.
| | - Nicola C James
- Department of Ichthyology and Fisheries Science, Rhodes University, Prince Alfred street, Makhanda, 6140, South Africa
- South African Institute for Aquatic Biodiversity, 11 Somerset street, Makhanda, 6139, South Africa
| | - Warren M Potts
- Department of Ichthyology and Fisheries Science, Rhodes University, Prince Alfred street, Makhanda, 6140, South Africa
| | - Amanda E Bates
- Department of Ocean Sciences, Memorial University of Newfoundland, 0 Marine Lab Rd, St. John’s, NL, A1C 5S7, Canada
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