1
|
Timpe AW, Seibel BA. Correcting systematic error in PO 2 measurement to improve measures of oxygen supply capacity (α). Comp Biochem Physiol A Mol Integr Physiol 2024; 298:111737. [PMID: 39244081 DOI: 10.1016/j.cbpa.2024.111737] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2024] [Revised: 09/03/2024] [Accepted: 09/04/2024] [Indexed: 09/09/2024]
Abstract
An organism's oxygen supply capacity, measured as a ratio of a metabolic rate to its critical oxygen partial pressure, describes the efficacy of oxygen uptake and transport. This metric is sensitive to errors in oxygen measurement, especially near anoxia where the magnitude of instrument error as a proportion of total signal is magnified. Here, we present a conceptual and mathematical method that uses this sensitivity to identify, quantify, and therefore correct oxygen measurements collected using inaccurately calibrated sensors. When appropriate, adding a small correction value to each oxygen measurement counteracts the effects of this error and provides results that are comparable to data from accurately calibrated oxygen probes. We demonstrate, using simulated, laboratory, and literature datasets, how this method can be used post hoc to diagnose error in, correct the magnitude of, and reduce the variability in repeat measures of traits relevant to oxygen tolerance.
Collapse
Affiliation(s)
- Alexander W Timpe
- College of Marine Science, University of South Florida, 830 1(st) St. S., St. Petersburg, FL 33701, USA.
| | - Brad A Seibel
- College of Marine Science, University of South Florida, 830 1(st) St. S., St. Petersburg, FL 33701, USA
| |
Collapse
|
2
|
Endress MGA, Penn JL, Boag TH, Burford BP, Sperling EA, Deutsch CA. Thermal optima in the hypoxia tolerance of marine ectotherms: Physiological causes and biogeographic consequences. PLoS Biol 2024; 22:e3002443. [PMID: 38227580 PMCID: PMC10790991 DOI: 10.1371/journal.pbio.3002443] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Accepted: 11/21/2023] [Indexed: 01/18/2024] Open
Abstract
The minimum O2 needed to fuel the demand of aquatic animals is commonly observed to increase with temperature, driven by accelerating metabolism. However, recent measurements of critical O2 thresholds ("Pcrit") reveal more complex patterns, including those with a minimum at an intermediate thermal "optimum". To discern the prevalence, physiological drivers, and biogeographic manifestations of such curves, we analyze new experimental and biogeographic data using a general dynamic model of aquatic water breathers. The model simulates the transfer of oxygen from ambient water through a boundary layer and into animal tissues driven by temperature-dependent rates of metabolism, diffusive gas exchange, and ventilatory and circulatory systems with O2-protein binding. We find that a thermal optimum in Pcrit can arise even when all physiological rates increase steadily with temperature. This occurs when O2 supply at low temperatures is limited by a process that is more temperature sensitive than metabolism, but becomes limited by a less sensitive process at warmer temperatures. Analysis of published species respiratory traits suggests that this scenario is not uncommon in marine biota, with ventilation and circulation limiting supply under cold conditions and diffusion limiting supply at high temperatures. Using occurrence data, we show that species with these physiological traits inhabit lowest O2 waters near the optimal temperature for hypoxia tolerance and are restricted to higher O2 at temperatures above and below this optimum. Our results imply that hypoxia tolerance can decline under both cold and warm conditions and thus may influence both poleward and equatorward species range limits.
Collapse
Affiliation(s)
- Martin-Georg A. Endress
- School of Oceanography, University of Washington, Seattle, Washington, United States of America
- Institute of Zoology, University of Cologne, Cologne, Germany
| | - Justin L. Penn
- School of Oceanography, University of Washington, Seattle, Washington, United States of America
- Department of Geosciences, Princeton University, Princeton, New Jersey, United States of America
| | - Thomas H. Boag
- Department of Geosciences, Princeton University, Princeton, New Jersey, United States of America
| | - Benjamin P. Burford
- Institute of Marine Sciences, University of California Santa Cruz, Santa Cruz, California, United States of America
- National Oceanic and Atmospheric Administration, National Marine Fisheries Service, Southwest Fisheries Science Center, Santa Cruz, California, United States of America
| | - Erik A. Sperling
- Department of Earth and Planetary Sciences, Stanford University, Stanford, California, United States of America
| | - Curtis A. Deutsch
- School of Oceanography, University of Washington, Seattle, Washington, United States of America
- Department of Geosciences, Princeton University, Princeton, New Jersey, United States of America
- High Meadows Environmental Institute, Princeton University, Princeton, New Jersey, United States of America
| |
Collapse
|
3
|
Atkinson D, Leighton G, Berenbrink M. Controversial Roles of Oxygen in Organismal Responses to Climate Warming. THE BIOLOGICAL BULLETIN 2022; 243:207-219. [PMID: 36548977 DOI: 10.1086/722471] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
AbstractDespite the global ecological importance of climate change, controversy surrounds how oxygen affects the fate of aquatic ectotherms under warming. Disagreements extend to the nature of oxygen bioavailability and whether oxygen usually limits growth under warming, explaining smaller adult size. These controversies affect two influential hypotheses: gill oxygen limitation and oxygen- and capacity-limited thermal tolerance. Here, we promote deeper integration of physiological and evolutionary mechanisms. We first clarify the nature of oxygen bioavailability in water, developing a new mass-transfer model that can be adapted to compare warming impacts on organisms with different respiratory systems and flow regimes. By distinguishing aerobic energy costs of moving oxygen from environment to tissues from costs of all other functions, we predict a decline in energy-dependent fitness during hypoxia despite approximately constant total metabolic rate before reaching critically low environmental oxygen. A new measure of oxygen bioavailability that keeps costs of generating water convection constant predicts a higher thermal sensitivity of oxygen uptake in an amphipod model than do previous oxygen supply indices. More importantly, by incorporating size- and temperature-dependent costs of generating water flow, we propose that oxygen limitation at different body sizes and temperatures can be modeled mechanistically. We then report little evidence for oxygen limitation of growth and adult size under benign warming. Yet occasional oxygen limitation, we argue, may, along with other selective pressures, help maintain adaptive plastic responses to warming. Finally, we discuss how to overcome flaws in a commonly used growth model that undermine predictions of warming impacts.
Collapse
|
4
|
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.
Collapse
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
| |
Collapse
|
5
|
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.
Collapse
|
6
|
Enriquez‐Urzelai U, Nicieza AG, Montori A, Llorente GA, Urrutia MB. Physiology and acclimation potential are tuned with phenology in larvae of a prolonged breeder amphibian. OIKOS 2021. [DOI: 10.1111/oik.08566] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
| | - Alfredo G. Nicieza
- Biodiversity Research Inst. (IMIB), Univ. of Oviedo‐Principality of Asturias‐CSIC Oviedo Spain
- Ecology Unit, Dept of Biology of Organisms and Systems, Univ. of Oviedo Oviedo Spain
| | - Albert Montori
- CREAC, Centre de Recerca i Educació Ambiental de Calafell, Calafell Barcelona Spain
| | - Gustavo A. Llorente
- Dept of Evolutionary Biology, Ecology and Environmental Sciences and Inst. de Recerca de la Biodiversitat (IRBIO), Faculty of Biology, Univ. of Barcelona Barcelona Spain
| | - Miren Bego Urrutia
- Depto de Genética, Antropología Física y Fisiología Animal, Univ. del País Vasco/Euskal Herriko Unibertsitatea Bilbao Spain
| |
Collapse
|
7
|
Walczyńska A, Sobczyk M. Aerobic scope does matter in the temperature-size rule, but only under optimal conditions. J Exp Biol 2021; 224:273421. [PMID: 34762122 DOI: 10.1242/jeb.242884] [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: 05/19/2021] [Accepted: 11/09/2021] [Indexed: 11/20/2022]
Abstract
We united theoretical predictions of the factors responsible for the evolutionary significance of the temperature-size rule (TSR). We assumed that (i) the TSR is a response to temperature-dependent oxic conditions, (ii) body size decrease is a consequence of cell shrinkage in response to hypoxia, (iii) this response enables organisms to maintain a wide scope for aerobic performance, and (iv) it prevents a decrease in fitness. We examined three clones of the rotifer Lecane inermis exposed to three experimental regimes: mild hypoxia, severe hypoxia driven by too high of a temperature, and severe hypoxia driven by an inadequate oxygen concentration. We compared the following traits in normoxia- and hypoxia-exposed rotifers: nuclear size (a proxy for cell size), body size, specific dynamic action (SDA, a proxy of aerobic metabolism) and two fitness measures, the population growth rate and eggs/female ratio. The results showed that (i) under mildly hypoxic conditions, our causative reasoning was correct, except that one of the clones decreased in body size without a decrease in nuclear size, and (ii) in more stressful environments, rotifers exhibited clone- and condition-specific responses, which were equally successful in terms of fitness levels. Our results indicate the importance of the testing conditions. The important conclusions were that (i) a body size decrease at higher temperatures enabled the maintenance of a wide aerobic scope under clone-specific, thermally optimal conditions, and (ii) this response was not the only option to prevent fitness reduction under hypoxia.
Collapse
Affiliation(s)
- Aleksandra Walczyńska
- Institute of Environmental Sciences, Jagiellonian University, Gronostajowa 7, 30-387 Krakow, Poland
| | - Mateusz Sobczyk
- Institute of Environmental Sciences, Jagiellonian University, Gronostajowa 7, 30-387 Krakow, Poland
| |
Collapse
|
8
|
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.
Collapse
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
| |
Collapse
|
9
|
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.
Collapse
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
| |
Collapse
|
10
|
Leeuwis RHJ, Zanuzzo FS, Peroni EFC, Gamperl AK. Research on sablefish ( Anoplopoma fimbria) suggests that limited capacity to increase heart function leaves hypoxic fish susceptible to heat waves. Proc Biol Sci 2021; 288:20202340. [PMID: 33715435 PMCID: PMC7944113 DOI: 10.1098/rspb.2020.2340] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Accepted: 02/11/2021] [Indexed: 01/19/2023] Open
Abstract
Studies of heart function and metabolism have been used to predict the impact of global warming on fish survival and distribution, and their susceptibility to acute and chronic temperature increases. Yet, despite the fact that hypoxia and high temperatures often co-occur, only one study has examined the effects of hypoxia on fish thermal tolerance, and the consequences of hypoxia for fish cardiac responses to acute warming have not been investigated. We report that sablefish (Anoplopoma fimbria) did not increase heart rate or cardiac output when warmed while hypoxic, and that this response was associated with reductions in maximum O2 consumption and thermal tolerance (CTmax) of 66% and approximately 3°C, respectively. Further, acclimation to hypoxia for four to six months did not substantially alter the sablefish's temperature-dependent physiological responses or improve its CTmax. These results provide novel, and compelling, evidence that hypoxia can impair the cardiac and metabolic response to increased temperatures in fish, and suggest that some coastal species may be more vulnerable to climate change-related heat waves than previously thought. Further, they support research showing that cross-tolerance and physiological plasticity in fish following hypoxia acclimation are limited.
Collapse
Affiliation(s)
- Robine H. J. Leeuwis
- Department of Ocean Sciences, Memorial University of Newfoundland, St John's, NL, Canada A1C 5S7
| | - Fábio S. Zanuzzo
- Department of Ocean Sciences, Memorial University of Newfoundland, St John's, NL, Canada A1C 5S7
| | - Ellen F. C. Peroni
- Department of Ocean Sciences, Memorial University of Newfoundland, St John's, NL, Canada A1C 5S7
| | - A. Kurt Gamperl
- Department of Ocean Sciences, Memorial University of Newfoundland, St John's, NL, Canada A1C 5S7
| |
Collapse
|
11
|
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.
Collapse
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
| |
Collapse
|
12
|
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.
Collapse
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
| |
Collapse
|
13
|
Deutsch C, Penn JL, Seibel B. Metabolic trait diversity shapes marine biogeography. Nature 2020; 585:557-562. [PMID: 32939093 DOI: 10.1038/s41586-020-2721-y] [Citation(s) in RCA: 67] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Accepted: 06/18/2020] [Indexed: 11/09/2022]
Abstract
Climate and physiology shape biogeography, yet the range limits of species can rarely be ascribed to the quantitative traits of organisms1-3. Here we evaluate whether the geographical range boundaries of species coincide with ecophysiological limits to acquisition of aerobic energy4 for a global cross-section of the biodiversity of marine animals. We observe a tight correlation between the metabolic rate and the efficacy of oxygen supply, and between the temperature sensitivities of these traits, which suggests that marine animals are under strong selection for the tolerance of low O2 (hypoxia)5. The breadth of the resulting physiological tolerances of marine animals predicts a variety of geographical niches-from the tropics to high latitudes and from shallow to deep water-which better align with species distributions than do models based on either temperature or oxygen alone. For all studied species, thermal and hypoxic limits are substantially reduced by the energetic demands of ecological activity, a trait that varies similarly among marine and terrestrial taxa. Active temperature-dependent hypoxia thus links the biogeography of diverse marine species to fundamental energetic requirements that are shared across the animal kingdom.
Collapse
Affiliation(s)
- Curtis Deutsch
- School of Oceanography, University of Washington, Seattle, WA, USA. .,Department of Biology, University of Washington, Seattle, WA, USA.
| | - Justin L Penn
- School of Oceanography, University of Washington, Seattle, WA, USA
| | - Brad Seibel
- College of Marine Science, University of South Florida, St Petersburg, FL, USA
| |
Collapse
|
14
|
Burton T, Einum S. The old and the large may suffer disproportionately during episodes of high temperature: evidence from a keystone zooplankton species. CONSERVATION PHYSIOLOGY 2020; 8:coaa038. [PMID: 32411372 PMCID: PMC7210711 DOI: 10.1093/conphys/coaa038] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Revised: 03/05/2020] [Accepted: 04/15/2020] [Indexed: 06/11/2023]
Abstract
Widespread declines in the body size of aquatic ectotherms have been attributed to the poorer ability of older, larger individuals to tolerate high temperature. Here, using the thermal death time curve framework, we investigate the relationship between temperature tolerance and size/age by measuring the change in heat tolerance of the keystone zooplankton species Daphnia magna across a range of temperature intensities (and hence exposures of varying duration) among individuals that differed up to 3-fold in size and thus varied in age also. Across the gradient of exposure temperatures, younger, smaller individuals were more tolerant than older, larger individuals. This suggests that the young and the small may be better equipped to withstand temperature challenges that are both intense/brief and more moderate/prolonged. Our study generalizes results obtained from more acute tolerance assays, providing physiological evidence consistent with the observed reductions in ectotherm body size as a response to warming in aquatic systems.
Collapse
Affiliation(s)
- Tim Burton
- Centre for Biodiversity Dynamics, Department of Biology, Norwegian University of Science and Technology, Realfagbygget, NO-7491 Trondheim, Norway
| | - Sigurd Einum
- Centre for Biodiversity Dynamics, Department of Biology, Norwegian University of Science and Technology, Realfagbygget, NO-7491 Trondheim, Norway
| |
Collapse
|
15
|
Burton T, Lakka HK, Einum S. Acclimation capacity and rate change through life in the zooplankton Daphnia. Proc Biol Sci 2020; 287:20200189. [PMID: 32228409 PMCID: PMC7209067 DOI: 10.1098/rspb.2020.0189] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Accepted: 03/10/2020] [Indexed: 12/26/2022] Open
Abstract
When a change in the environment occurs, organisms can maintain an optimal phenotypic state via plastic, reversible changes to their phenotypes. These adjustments, when occurring within a generation, are described as the process of acclimation. While acclimation has been studied for more than half a century, global environmental change has stimulated renewed interest in quantifying variation in the rate and capacity with which this process occurs, particularly among ectothermic organisms. Yet, despite the likely ecological importance of acclimation capacity and rate, how these traits change throughout life among members of the same species is largely unstudied. Here we investigate these relationships by measuring the acute heat tolerance of the clonally reproducing zooplankter Daphnia magna of different size/age and acclimation status. The heat tolerance of individuals completely acclimated to relatively warm (28°C) or cool (17°C) temperatures diverged during development, indicating that older, larger individuals had a greater capacity to increase heat tolerance. However, when cool acclimated individuals were briefly exposed to the warm temperature (i.e. were 'heat-hardened'), it was younger, smaller animals with less capacity to acclimate that were able to do so more rapidly because they obtained or came closer to obtaining complete acclimation of heat tolerance. Our results illustrate that within a species, individuals can differ substantially in how rapidly and by how much they can respond to environmental change. We urge greater investigation of the intraspecific relationship between acclimation and development along with further consideration of the factors that might contribute to these enigmatic patterns of phenotypic variation.
Collapse
Affiliation(s)
- Tim Burton
- Centre for Biodiversity Dynamics, Department of Biology, Norwegian University of Science and Technology, Realfagbygget, NO-7491 Trondheim, Norway
| | - Hanna-Kaisa Lakka
- Centre for Biodiversity Dynamics, Department of Biology, Norwegian University of Science and Technology, Realfagbygget, NO-7491 Trondheim, Norway
- Department of Biological and Environmental Science, University of Jyväskylä, Jyväskylä, Finland
| | - Sigurd Einum
- Centre for Biodiversity Dynamics, Department of Biology, Norwegian University of Science and Technology, Realfagbygget, NO-7491 Trondheim, Norway
| |
Collapse
|