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Wassenaar LI, Crespel A, Barth JAC, Koeck B, Závorka L. Non-invasive determination of critical dissolved oxygen thresholds for stress physiology in fish using triple-oxygen stable isotopes and aquatic respirometry. ISOTOPES IN ENVIRONMENTAL AND HEALTH STUDIES 2024:1-15. [PMID: 38949394 DOI: 10.1080/10256016.2024.2366470] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2024] [Accepted: 05/14/2024] [Indexed: 07/02/2024]
Abstract
Understanding the critical thresholds of dissolved oxygen (O2) that trigger adaptive physiological responses in aquatic organisms is long hampered by a lack of robust, non-lethal or non-invasive methodologies. The isotope fractionation of triple O2 isotopes (18O/17O/16O) during respiration is linked to the amount of oxygen utilised, offering a potential avenue for new insights. Our experimental research involved measuring the oxygen isotope fractionation of dissolved O2 in closed-system aquatic respirometry experiments with wild sticklebacks (Gasterosteus aculeatus). These fish were either naturally adapted or experimentally acclimated to hypoxic and normoxic conditions. The aim was to observe their oxygen usage and isotope fractionation in response to increasingly severe hypoxia. Initial observations revealed a progressive 18O enrichment from the preferential uptake of 16O to a dissolved oxygen threshold of 3-5 mg O2 L-1, followed by an apparent reversal in oxygen isotope fractionation, which is mixing of 16O and 17O with the remaining O2 pool across all populations and indicative of a systematic change in oxygen metabolism among the fish. Unexpectedly, sticklebacks adapted to hypoxia but acclimated to normoxia exhibited stronger oxygen isotope fractionation compared to those adapted to normoxia and acclimated to hypoxia, contradicting the hypothesis that hypoxia adaptation would lead to reduced isotope discrimination due to more efficient oxygen uptake. These preliminary experimental results highlight the novel potential of using dissolved O2 isotopes as a non-invasive, non-lethal method to quantitatively assess metabolic thresholds in aquatic organisms. This approach could significantly improve our understanding of the critical oxygen responses and adaptation mechanisms in fish and other aquatic organisms across different oxygen environments, marking a significant step forward in aquatic ecological and physiological research.
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Affiliation(s)
- Leonard I Wassenaar
- WasserCluster Lunz Biologische Station GmbH, Lunz am See, Austria
- Danube University Krems, Krems, Austria
| | - Amélie Crespel
- Department of Biology, University of Turku, Turku, Finland
| | - Johannes A C Barth
- Department of Geography and Geosciences, GeoZentrum Nordbayern, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Barbara Koeck
- WasserCluster Lunz Biologische Station GmbH, Lunz am See, Austria
| | - Libor Závorka
- WasserCluster Lunz Biologische Station GmbH, Lunz am See, Austria
- Danube University Krems, Krems, Austria
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2
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Boggs TE, Gross JB. Gill morphology adapted to oxygen-limited caves in Astyanax mexicanus. JOURNAL OF EXPERIMENTAL ZOOLOGY. PART A, ECOLOGICAL AND INTEGRATIVE PHYSIOLOGY 2024. [PMID: 39031584 DOI: 10.1002/jez.2840] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2024] [Revised: 05/20/2024] [Accepted: 05/23/2024] [Indexed: 07/22/2024]
Abstract
Sensing and acquiring dissolved oxygen is crucial for nearly all aquatic life. This may become even more vital as dissolved oxygen concentrations continue to decline in many aquatic environments. While certain phenotypes that enable fish to live in low oxygen have been characterized, adaptations that arise following sudden, drastic reductions in dissolved oxygen are relatively unknown. Here, we assessed the blind Mexican cavefish, Astyanax mexicanus, for alterations to gill morphology that may be adaptive for life in hypoxic caves. The Astyanax system provides the unique opportunity to compare gill morphology between stereotypical "surface" adapted morphotypes and obligate cave-dwelling conspecifics. While the surface environment is well-oxygenated, cavefish must cope with significantly reduced oxygen. We began by quantifying traditional morphological gill traits including filament number and length as well as lamellar density and height in surface fish and two distinct cave populations, Pachón and Tinaja. This enabled us to estimate total lamellar height, a proxy for gill surface area. We then used immunohistochemical staining to label 5-HT-positive neuroepithelial cells (NECs), which serve as key oxygen sensors in fish. We discovered an increase in gill surface area for both cavefish populations compared to surface, which may enable a higher capacity of oxygen acquisition. Additionally, we found more NECs in Pachón cavefish compared to both surface fish and Tinaja cavefish, suggesting certain selective pressures may be cave-specific. Collectively, this work provides evidence that cavefish have adapted to low oxygen conditions via alterations to gill morphology and oxygen sensing, and informs evolutionary mechanisms of rapid adaptation to dramatic, chronic hypoxia.
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Affiliation(s)
- Tyler E Boggs
- Department of Biological Sciences, University of Cincinnati, Cincinnati, Ohio, USA
| | - Joshua B Gross
- Department of Biological Sciences, University of Cincinnati, Cincinnati, Ohio, USA
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3
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Chen J, Hu Z, Li P, Wang G, Wei H, Li Q, Fu B, Sun Y. Transcriptomic atlas for hypoxia and following re-oxygenation in Ancherythroculter nigrocauda heart and brain tissues: insights into gene expression, alternative splicing, and signaling pathways. Front Genet 2024; 15:1365285. [PMID: 38689653 PMCID: PMC11058841 DOI: 10.3389/fgene.2024.1365285] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2024] [Accepted: 03/22/2024] [Indexed: 05/02/2024] Open
Abstract
Hypoxia is a mounting problem that affects the world's freshwaters, with severe consequence for many species, including death and large economical loss. The hypoxia problem has increased recently due to the combined effects of water eutrophication and global warming. In this study, we investigated the transcriptome atlas for the bony fish Ancherythroculter nigrocauda under hypoxia for 1.5, 3, and 4.5 h and its recovery to normal oxygen levels in heart and brain tissues. We sequenced 21 samples for brain and heart tissues (a total of 42 samples) plus three control samples and obtained an average of 32.40 million raw reads per sample, and 95.24% mapping rate of the filtered clean reads. This robust transcriptome dataset facilitated the discovery of 52,428 new transcripts and 6,609 novel genes. In the heart tissue, the KEGG enrichment analysis showed that genes linked to the Vascular smooth muscle contraction and MAPK and VEGF signaling pathways were notably altered under hypoxia. Re-oxygenation introduced changes in genes associated with abiotic stimulus response and stress regulation. In the heart tissue, weighted gene co-expression network analysis pinpointed a module enriched in insulin receptor pathways that was correlated with hypoxia. Conversely, in the brain tissue, the response to hypoxia was characterized by alterations in the PPAR signaling pathway, and re-oxygenation influenced the mTOR and FoxO signaling pathways. Alternative splicing analysis identified an average of 27,226 and 28,290 events in the heart and brain tissues, respectively, with differential events between control and hypoxia-stressed groups. This study offers a holistic view of transcriptomic adaptations in A. nigrocauda heart and brain tissues under oxygen stress and emphasizes the role of gene expression and alternative splicing in the response mechanisms.
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Affiliation(s)
- Jian Chen
- Fisheries Research Institute, Wuhan Academy of Agricultural Sciences, Wuhan, China
| | - Zhen Hu
- Hubei Provincial Fisheries Technology Extension Center, Wuhan, China
| | - Pei Li
- Fisheries Research Institute, Wuhan Academy of Agricultural Sciences, Wuhan, China
| | - Guiying Wang
- Fisheries Research Institute, Wuhan Academy of Agricultural Sciences, Wuhan, China
| | - Huijie Wei
- Fisheries Research Institute, Wuhan Academy of Agricultural Sciences, Wuhan, China
| | - Qing Li
- Fisheries Research Institute, Wuhan Academy of Agricultural Sciences, Wuhan, China
| | - Beide Fu
- Ruibiao (Wuhan) Biotechnology Co., Ltd, Wuhan, China
| | - Yanhong Sun
- Fisheries Research Institute, Wuhan Academy of Agricultural Sciences, Wuhan, China
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4
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Lukhabi DK, Mensah PK, Asare NK, Akwetey MFA, Faseyi CA. Benthic macroinvertebrates as indicators of water quality: A case study of estuarine ecosystems along the coast of Ghana. Heliyon 2024; 10:e28018. [PMID: 38596140 PMCID: PMC11002552 DOI: 10.1016/j.heliyon.2024.e28018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Revised: 02/09/2024] [Accepted: 03/11/2024] [Indexed: 04/11/2024] Open
Abstract
Increasing human activities in coastal areas of Ghana have led to the degradation of many surface waterbodies, with significant consequences for the ecosystems in the affected areas. Thus, this degradation extremely affects the health of ecosystems and disrupts the essential services they provide. The present study explored the use of benthic macroinvertebrates as an indicator of estuarine degradation along the coast of Ghana. Water and sediment samples were collected bimonthly from Ankobra, Kakum and Volta estuaries for physicochemical parameters, nutrients and benthic macroinvertebrates. The findings revealed the dominance of pollution-tolerant taxa such as Capitella sp., Nereis sp., Heteromastus sp., Tubifex sp., Cossura sp. and Chironomous sp. in Kakum Estuary while pollution-sensitive taxa such as Scoloplos sp., Euridice sp., Lumbriconereis sp. and Pachymelania sp. in the Volta Estuary. The species-environment interactions showed dissolved oxygen, temperature, salinity, orthophosphate, nitrates, ammonium, electrical conductivity, turbidity, and chemical oxygen demand as the most significant parameters that complement the use of benthic macroinvertebrates as indicators of environmental quality in the studied estuaries. There were correlations of some benthic macroinvertebrate taxa with environmental factors in the estuaries suggesting low, moderate and high levels of pollution in the Volta, Kakum and Ankobra estuaries, respectively. Nevertheless, the study finds Kakum Estuary to be the ecologically healthiest estuary than the Volta and Ankobra Estuaries. Therefore, the study has shown benthic macroinvertebrates as a key indicator of ecosystem health alterations, and it is recommended that they should be incorporated with other environmental data for pollution monitoring in Ghanaian coastal waters.
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Affiliation(s)
- Dorothy Khasisi Lukhabi
- Centre for Coastal Management-Africa Centre of Excellence in Coastal Resilience, University of Cape Coast, Cape Coast 00223, Ghana
- Department of Fisheries and Aquatic Sciences, School of Biological Sciences, University of Cape Coast, Ghana
| | - Paul Kojo Mensah
- Department of Fisheries and Aquatic Sciences, School of Biological Sciences, University of Cape Coast, Ghana
- Institute for Water Research, Rhodes University, Makhanda 6140, South Africa
| | - Noble Kwame Asare
- Centre for Coastal Management-Africa Centre of Excellence in Coastal Resilience, University of Cape Coast, Cape Coast 00223, Ghana
- Department of Fisheries and Aquatic Sciences, School of Biological Sciences, University of Cape Coast, Ghana
| | | | - Charles Abimbola Faseyi
- Centre for Coastal Management-Africa Centre of Excellence in Coastal Resilience, University of Cape Coast, Cape Coast 00223, Ghana
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5
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Filice M, Gattuso A, Imbrogno S, Mazza R, Amelio D, Caferro A, Agnisola C, Icardo JM, Cerra MC. Functional, structural, and molecular remodelling of the goldfish (Carassius auratus) heart under moderate hypoxia. FISH PHYSIOLOGY AND BIOCHEMISTRY 2024; 50:667-685. [PMID: 38198074 PMCID: PMC11021278 DOI: 10.1007/s10695-024-01297-7] [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: 07/24/2023] [Accepted: 01/01/2024] [Indexed: 01/11/2024]
Abstract
The goldfish (Carassius auratus) is known for its physiologic ability to survive even long periods of oxygen limitation (hypoxia), adapting the cardiac performance to the requirements of peripheral tissue perfusion. We here investigated the effects of short-term moderate hypoxia on the heart, focusing on ventricular adaptation, in terms of hemodynamics and structural traits. Functional evaluations revealed that animals exposed to 4 days of environmental hypoxia increased the hemodynamic performance evaluated on ex vivo cardiac preparations. This was associated with a thicker and more vascularized ventricular compact layer and a reduced luminal lacunary space. Compared to normoxic animals, ventricular cardiomyocytes of goldfish exposed to hypoxia showed an extended mitochondrial compartment and a modulation of proteins involved in mitochondria dynamics. The enhanced expression of the pro-fission markers DRP1 and OMA1, and the modulation of the short and long forms of OPA1, suggested a hypoxia-related mitochondria fission. Our data propose that under hypoxia, the goldfish heart undergoes a structural remodelling associated with a potentiated cardiac activity. The energy demand for the highly performant myocardium is supported by an increased number of mitochondria, likely occurring through fission events.
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Affiliation(s)
- Mariacristina Filice
- Department of Biology, Ecology and Earth Sciences, University of Calabria, Arcavacata di Rende, Italy
| | - Alfonsina Gattuso
- Department of Biology, Ecology and Earth Sciences, University of Calabria, Arcavacata di Rende, Italy
| | - Sandra Imbrogno
- Department of Biology, Ecology and Earth Sciences, University of Calabria, Arcavacata di Rende, Italy.
| | - Rosa Mazza
- Department of Biology, Ecology and Earth Sciences, University of Calabria, Arcavacata di Rende, Italy
| | - Daniela Amelio
- Department of Biology, Ecology and Earth Sciences, University of Calabria, Arcavacata di Rende, Italy
| | - Alessia Caferro
- Department of Biology, Ecology and Earth Sciences, University of Calabria, Arcavacata di Rende, Italy
| | - Claudio Agnisola
- Department of Biological Sciences, University of Naples Federico II, Naples, Italy
| | - José Manuel Icardo
- Department of Anatomy and Cell Biology, University of Cantabria, Santander, Spain
| | - Maria Carmela Cerra
- Department of Biology, Ecology and Earth Sciences, University of Calabria, Arcavacata di Rende, Italy
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6
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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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7
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Deutsch C, Penn JL, Lucey N. Climate, Oxygen, and the Future of Marine Biodiversity. ANNUAL REVIEW OF MARINE SCIENCE 2024; 16:217-245. [PMID: 37708422 DOI: 10.1146/annurev-marine-040323-095231] [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: 09/16/2023]
Abstract
The ocean enabled the diversification of life on Earth by adding O2 to the atmosphere, yet marine species remain most subject to O2 limitation. Human industrialization is intensifying the aerobic challenges to marine ecosystems by depleting the ocean's O2 inventory through the global addition of heat and local addition of nutrients. Historical observations reveal an ∼2% decline in upper-ocean O2 and accelerating reports of coastal mass mortality events. The dynamic balance of O2 supply and demand provides a unifying framework for understanding these phenomena across scales from the global ocean to individual organisms. Using this framework, we synthesize recent advances in forecasting O2 loss and its impacts on marine biogeography, biodiversity, and biogeochemistry. We also highlight three outstanding uncertainties: how long-term global climate change intensifies ocean weather events in which simultaneous heat and hypoxia create metabolic storms, how differential species O2 sensitivities alter the structure of ecological communities, and how global O2 loss intersects with coastal eutrophication. Projecting these interacting impacts on future marine ecosystems requires integration of climate dynamics, biogeochemistry, physiology, and ecology, evaluated with an eye on Earth history. Reducing global and local impacts of warming and O2 loss will be essential if humankind is to preserve the health and biodiversity of the future ocean.
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Affiliation(s)
- Curtis Deutsch
- Department of Geosciences, Princeton University, Princeton, New Jersey, USA;
- High Meadows Environmental Institute, Princeton University, Princeton, New Jersey, USA
| | - Justin L Penn
- Department of Geosciences, Princeton University, Princeton, New Jersey, USA;
| | - Noelle Lucey
- High Meadows Environmental Institute, Princeton University, Princeton, New Jersey, USA
- Smithsonian Tropical Research Institute, Balboa Ancón, Panama
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8
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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.
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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
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9
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Frank L, Serafy J, Grosell M. A large aerobic scope and complex regulatory abilities confer hypoxia tolerance in larval toadfish, Opsanus beta, across a wide thermal range. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 899:165491. [PMID: 37453709 DOI: 10.1016/j.scitotenv.2023.165491] [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: 04/14/2023] [Revised: 07/05/2023] [Accepted: 07/10/2023] [Indexed: 07/18/2023]
Abstract
Few studies have been performed on early-life stage toadfish, and none have addressed their tolerance to temperature and hypoxia despite large seasonal temperature fluctuations and daily hypoxia in their natural environment. The first directed captive breeding of Opsanus beta allowed the examination of larval oxygen demands and hypoxia tolerance across the range of their environmental temperatures (23-33 °C). Larval toadfish exhibited a surprisingly large aerobic scope across the tested temperature range. In response to progressive hypoxia, larval toadfish showed early metabolic depression and a low regulation index (RI), while juveniles had higher regulatory abilities but, unexpectedly, a lower aerobic scope. Larval and juvenile toadfish survived hours of severe hypoxia, but larval fish had a higher excessive post-hypoxia oxygen consumption, yet their metabolic rate returned to RMR in the same timeframe as the juveniles, likely due to their higher aerobic scope. We defined hypoxia tolerance using a physiological trait, p50, the oxygen tension in which oxygen uptake is reduced to 50 % of the metabolic rate at rest and determined it at all tested temperatures. Comparing these p50 values to environmental conditions in Florida Bay using hourly temperature and oxygen measurements from January 2014-October 2021 revealed that larval toadfish rarely experience < p50 conditions (11 % of events). Further, the median duration of these events was 3 h. The metabolic performance of larval toadfish combined with temperature and oxygen observations from their natural environment reveals the fascinating strategy in which larval toadfish survive diel hypoxia across seasons.
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Affiliation(s)
- LeeAnn Frank
- Department of Marine Biology and Ecology, Rosenstiel School of Marine, Atmospheric, and Earth Science, University of Miami, 4600 Rickenbacker Causeway, Miami, FL 33149, USA.
| | - Joseph Serafy
- Department of Marine Biology and Ecology, Rosenstiel School of Marine, Atmospheric, and Earth Science, University of Miami, 4600 Rickenbacker Causeway, Miami, FL 33149, USA; NOAA National Marine Fisheries Service, 75 Virginia Beach Dr, Key Biscayne, FL 33149 Miami, FL, USA
| | - Martin Grosell
- Department of Marine Biology and Ecology, Rosenstiel School of Marine, Atmospheric, and Earth Science, University of Miami, 4600 Rickenbacker Causeway, Miami, FL 33149, USA
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10
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Bergsson H, Svendsen MBS, Steffensen JF. Model of Oxygen Conditions within Aquaculture Sea Cages. BIOLOGY 2023; 12:1408. [PMID: 37998007 PMCID: PMC10669768 DOI: 10.3390/biology12111408] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2023] [Revised: 11/01/2023] [Accepted: 11/04/2023] [Indexed: 11/25/2023]
Abstract
To ensure optimal feed intake, growth, and general fish health in aquaculture sea cages, interactions between drivers that affect oxygen conditions need to be understood. The main drivers are oxygen consumption and water exchange, caused by flow through the cage. Swimming energetics in rainbow trout (Oncorhynchus mykiss) in normoxia and hypoxia at 10, 15, and 20 °C were determined. Using the determinations, a conceptual model of oxygen conditions within sea cages was created. By applying the model to a case study, results show that with a temperature increase of 10 °C, oxygen concentration will decrease three times faster. To maintain optimal oxygen concentration within the cage, the flow velocity must be increased by a factor of 3.7. The model is highly relevant for current farms since the model predictions can explain why and when suboptimal conditions occur within the cages. Using the same method, the model can be used to estimate the suitability of potential new aquaculture sites.
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Affiliation(s)
- Heiðrikur Bergsson
- Marine Biological Section, Department of Biology, University of Copenhagen, DK-3000 Elsinore, Denmark; (M.B.S.S.); (J.F.S.)
- Hiddenfjord, Við Ánna 1, FO-512 Norðragøta, Faroe Islands
| | - Morten Bo Søndergaard Svendsen
- Marine Biological Section, Department of Biology, University of Copenhagen, DK-3000 Elsinore, Denmark; (M.B.S.S.); (J.F.S.)
- Copenhagen Academy for Medical Education and Simulation, Rigshospitalet, Capital Region of Denmark, DK-2100 Copenhagen, Denmark
- Department of Computer Science, University of Copenhagen, DK-2100 Copenhagen, Denmark
| | - John Fleng Steffensen
- Marine Biological Section, Department of Biology, University of Copenhagen, DK-3000 Elsinore, Denmark; (M.B.S.S.); (J.F.S.)
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11
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Harford AR, Devaux JBL, Hickey AJR. Dynamic defence? Intertidal triplefin species show better maintenance of mitochondrial membrane potential than subtidal species at low oxygen pressures. J Exp Biol 2023; 226:jeb245926. [PMID: 37498237 DOI: 10.1242/jeb.245926] [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: 04/03/2023] [Accepted: 07/14/2023] [Indexed: 07/28/2023]
Abstract
Oxygen is essential for most eukaryotic lifeforms, as it supports mitochondrial oxidative phosphorylation to supply ∼90% of cellular adenosine triphosphate (ATP). Fluctuations in O2 present a major stressor, with hypoxia leading to a cascade of detrimental physiological changes that alter cell operations and ultimately induce death. Nonetheless, some species episodically tolerate near-anoxic environments, and have evolved mechanisms to sustain function even during extended hypoxic periods. While mitochondria are pivotal in central metabolism, their role in hypoxia tolerance remains ill defined. Given the vulnerability of the brain to hypoxia, mitochondrial function was tested in brain homogenates of three closely related triplefin species with varying degrees of hypoxia tolerance (Bellapiscis medius, Forsterygion lapillum and Forsterygion varium). High-resolution respirometry coupled with fluorometric measurements of mitochondrial membrane potential (mtMP) permitted assessment of differences in mitochondrial function and integrity in response to intermittent hypoxia and anoxia. Traditional steady-state measures of respiratory flux and mtMP showed no differences among species. However, in the transition into anoxia, the tolerant species B. medius and F. lapillum maintained mtMP at O2 pressures 7- and 4.4-fold lower, respectively, than that of the hypoxia-sensitive F. varium and exhibited slower rates of membrane depolarisation. The results indicate that dynamic oxic-hypoxic mitochondria transitions underlie hypoxia tolerance in these intertidal fish.
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Affiliation(s)
- Alice R Harford
- School of Biological Sciences, University of Auckland, Auckland 1010, New Zealand
| | - Jules B L Devaux
- School of Biological Sciences, University of Auckland, Auckland 1010, New Zealand
| | - Anthony J R Hickey
- School of Biological Sciences, University of Auckland, Auckland 1010, New Zealand
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12
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Bowering LR, McArley TJ, Devaux JBL, Hickey AJR, Herbert NA. Metabolic resilience of the Australasian snapper ( Chrysophrys auratus) to marine heatwaves and hypoxia. Front Physiol 2023; 14:1215442. [PMID: 37528894 PMCID: PMC10387550 DOI: 10.3389/fphys.2023.1215442] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Accepted: 07/05/2023] [Indexed: 08/03/2023] Open
Abstract
Marine organisms are under threat from a simultaneous combination of climate change stressors, including warming sea surface temperatures (SST), marine heatwave (MHW) episodes, and hypoxic events. This study sought to investigate the impacts of these stressors on the Australasian snapper (C. auratus) - a finfish species of high commercial and recreational importance, from the largest snapper fishery in Aotearoa New Zealand (SNA1). A MHW scenario was simulated from 21°C (current February SST average for north-eastern New Zealand) to a future predicted level of 25°C, with the whole-animal and mitochondrial metabolic performance of snapper in response to hypoxia and elevated temperature tested after 1-, 10-, and 30-days of thermal challenge. It was hypothesised that key indicators of snapper metabolic performance would decline after 1-day of MHW stress, but that partial recovery might arise as result of thermal plasticity after chronic (e.g., 30-day) exposures. In contrast to this hypothesis, snapper performance remained high throughout the MHW: 1) Aerobic metabolic scope increased after 1-day of 25°C exposure and remained high. 2) Hypoxia tolerance, measured as the critical O2 pressure and O2 pressure where loss of equilibrium occurred, declined after 1-day of warm-acclimation, but recovered quickly with no observable difference from the 21°C control following 30-days at 25°C. 3) The performance of snapper mitochondria was also maintained, with oxidative phosphorylation respiration and proton leak flux across the inner mitochondrial membrane of the heart remaining mostly unaffected. Collectively, the results suggest that heart mitochondria displayed resilience, or plasticity, in snapper chronically exposed to 25°C. Therefore, contrary to the notion of climate change having adverse metabolic effects, future temperatures approaching 25°C may be tolerated by C. auratus in Northern New Zealand. Even in conjunction with supplementary hypoxia, 25°C appears to represent a metabolically optimal temperature for this species.
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Affiliation(s)
- Lyvia R. Bowering
- Institute of Marine Science, University of Auckland, Leigh, New Zealand
| | | | - Jules B. L. Devaux
- School of Biological Sciences, University of Auckland, Auckland, New Zealand
| | | | - Neill A. Herbert
- Institute of Marine Science, University of Auckland, Leigh, New Zealand
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13
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Firth BL, Craig PM, Drake DAR, Power M. Seasonal, environmental and individual effects on hypoxia tolerance of eastern sand darter ( Ammocrypta pellucida). CONSERVATION PHYSIOLOGY 2023; 11:coad008. [PMID: 36926473 PMCID: PMC10012177 DOI: 10.1093/conphys/coad008] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Revised: 01/04/2023] [Accepted: 03/07/2023] [Indexed: 06/18/2023]
Abstract
Metabolic rate and hypoxia tolerance are highly variable among individual fish in a stable environment. Understanding the variability of these measures in wild fish populations is critical for assessing adaptive potential and determining local extinction risks as a result of climate-induced fluctuations in temperature and hypoxic conditions. We assessed the field metabolic rate (FMR) and two hypoxia tolerance metrics, oxygen pressure at loss of equilibrium (PO2 at LOE) and critical oxygen tolerance (Pcrit) of wild-captured eastern sand darter (Ammocrypta pellucida), a threatened species in Canada, using field trials (June to October) that encompassed ambient water temperatures and oxygen conditions typically experienced by the species. Temperature was significantly and positively related to hypoxia tolerance but not FMR. Temperature alone explained 1%, 31% and 7% of the variability observed in FMR, LOE, and Pcrit, respectively. Environmental and fish-specific factors such as reproductive season and condition explained much of the residual variation. Reproductive season significantly affected FMR by increasing it by 159-176% over the tested temperature range. Further understanding the impact of reproductive season on metabolic rate over a temperature range is crucial for understanding how climate change could impact species fitness. Among-individual variation in FMR significantly increased with temperature while among-individual variation in both hypoxia tolerance metrics did not. A large degree of variation in FMR in the summer might allow for evolutionary rescue with increasing mean and variance of global temperatures. Findings suggest that temperature may be a weak predictor in a field setting where biotic and abiotic factors can act concurrently on variables that affect physiological tolerance.
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Affiliation(s)
- Britney L Firth
- Corresponding author: Department of Biology, University of Waterloo, 200 University Avenue West, Waterloo, ON, N2L 3G1, Canada.
| | - Paul M Craig
- Department of Biology, University of Waterloo, Waterloo, ON, N2L 3G1, Canada
| | - D Andrew R Drake
- Great Lakes Laboratory for Fisheries and Aquatic Sciences, Fisheries and Oceans Canada, Burlington, ON, L7S 1A1, Canada
| | - Michael Power
- Department of Biology, University of Waterloo, Waterloo, ON, N2L 3G1, Canada
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14
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Molina JM, Kunzmann A, Reis JP, Guerreiro PM. Metabolic Responses and Resilience to Environmental Challenges in the Sedentary Batrachoid Halobatrachus didactylus (Bloch & Schneider, 1801). Animals (Basel) 2023; 13:ani13040632. [PMID: 36830420 PMCID: PMC9951689 DOI: 10.3390/ani13040632] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2022] [Revised: 02/06/2023] [Accepted: 02/10/2023] [Indexed: 02/16/2023] Open
Abstract
In the context of climate change, warming of the seas and expansion of hypoxic zones are challenges that most species of fish are, or will be subjected to. Understanding how different species cope with these changes in their environment at the individual level can shed light on how populations and ecosystems will be affected. We provide first-time estimates on the metabolic rates, thermal, and oxygen-related limits for Halobatrachus didactylus, a coastal sedentary fish that lives in intertidal environments of the Northeast Atlantic. Using respirometry in different experimental designs, we found that this species is highly resistant to acute thermal stress (CTmax: 34.82 ± 0.66 °C) and acute hypoxia (Pcrit: 0.59-1.97 mg O2 L-1). We found size-specific differences in this stress response, with smaller individuals being more sensitive. We also quantified its aerobic scope and daily activity patterns, finding this fish to be extremely sedentary, with one of the lowest standard metabolic rates found in temperate fish (SMR: 14.96 mg O2 kg-1h-1). H. didactylus activity increases at night, when its metabolic rate increases drastically (RMR: 36.01 mg O2 kg-1h-1). The maximum metabolic rate of H. didactylus was estimated to be 67.31 mg O2 kg-1h-1, producing an aerobic scope of 52.35 mg O2 kg-1h-1 (77.8% increase). The metrics obtained in this study prove that H. didactylus is remarkably resilient to acute environmental variations in temperature and oxygen content, which might enable it to adapt to the extreme abiotic conditions forecasted for the world's oceans in the near future.
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Affiliation(s)
- Juan Manuel Molina
- Instituto Argentino de Oceanografía (CONICET), Bahía Blanca B8000, Argentina
- Leibniz-Zentrum für Marine Tropenforschung (ZMT), 28359 Bremen, Germany
- Centro de Ciências do Mar (CCMAR), Universidade do Algarve, 8005-139 Faro, Portugal
- Correspondence:
| | - Andreas Kunzmann
- Leibniz-Zentrum für Marine Tropenforschung (ZMT), 28359 Bremen, Germany
| | - João Pena Reis
- Centro de Ciências do Mar (CCMAR), Universidade do Algarve, 8005-139 Faro, Portugal
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15
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Cerra MC, Filice M, Caferro A, Mazza R, Gattuso A, Imbrogno S. Cardiac Hypoxia Tolerance in Fish: From Functional Responses to Cell Signals. Int J Mol Sci 2023; 24:ijms24021460. [PMID: 36674975 PMCID: PMC9866870 DOI: 10.3390/ijms24021460] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Revised: 01/09/2023] [Accepted: 01/10/2023] [Indexed: 01/14/2023] Open
Abstract
Aquatic animals are increasingly challenged by O2 fluctuations as a result of global warming, as well as eutrophication processes. Teleost fish show important species-specific adaptability to O2 deprivation, moving from intolerance to a full tolerance of hypoxia and even anoxia. An example is provided by members of Cyprinidae which includes species that are amongst the most tolerant hypoxia/anoxia teleosts. Living at low water O2 requires the mandatory preservation of the cardiac function to support the metabolic and hemodynamic requirements of organ and tissues which sustain whole organism performance. A number of orchestrated events, from metabolism to behavior, converge to shape the heart response to the restricted availability of the gas, also limiting the potential damages for cells and tissues. In cyprinids, the heart is extraordinarily able to activate peculiar strategies of functional preservation. Accordingly, by using these teleosts as models of tolerance to low O2, we will synthesize and discuss literature data to describe the functional changes, and the major molecular events that allow the heart of these fish to sustain adaptability to O2 deprivation. By crossing the boundaries of basic research and environmental physiology, this information may be of interest also in a translational perspective, and in the context of conservative physiology, in which the output of the research is applicable to environmental management and decision making.
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16
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Novel physiological data needed for progress in global change ecology. Basic Appl Ecol 2023. [DOI: 10.1016/j.baae.2023.01.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
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17
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Anders N, Hannaas S, Saltskår J, Schuster E, Tenningen M, Totland B, Vold A, Øvredal JT, Breen M. Vitality as a measure of animal welfare during purse seine pumping related crowding of Atlantic mackerel (Scomber scrombrus). Sci Rep 2022; 12:21949. [PMID: 36536033 PMCID: PMC9763418 DOI: 10.1038/s41598-022-26373-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Accepted: 12/14/2022] [Indexed: 12/24/2022] Open
Abstract
The impacts of wild capture fishing on animal welfare are poorly understood. During purse seine fishing for Atlantic mackerel (Scomber scrombrus), catches are crowded to high densities to facilitate pumping onboard. This study aimed to monitor fish welfare during crowding events in the Norwegian purse seine fishery, and to identify relevant drivers. We first correlated a suite of neuro-endocrine, physiological and physical stress responses (integrated into a single measure of welfare using multivariate analysis) to the behavioural vitality of individual mackerel in controlled crowding trials in aquaculture cages. Vitality was found to be a useful measure of welfare. We then assessed individual fish vitality onboard a commercial purse seiner. Catch welfare, measured using vitality, was observed to be negatively impacted during pumping related crowding. Larger catches and longer crowding exposure times resulted in greater negative impacts. Vitality was not significantly impacted by crowding density or dissolved oxygen concentrations inside the net, although methodological limitations limited accurate measurement of these parameters. Blood lactate levels correlated negatively with vitality, suggesting that high-intensity anaerobic locomotory activity was associated with the reduction in welfare. Based on these findings, catch welfare could be improved by targeting smaller schools to minimise crowding exposure times.
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Affiliation(s)
- Neil Anders
- grid.10917.3e0000 0004 0427 3161Institute of Marine Research (IMR), Fish Capture Division, Nordnes. NO-5817, Nordnesgaten 50, P.O. Box 1870, 5005 Bergen, Norway
| | - Sigurd Hannaas
- grid.10917.3e0000 0004 0427 3161Institute of Marine Research (IMR), Fish Capture Division, Nordnes. NO-5817, Nordnesgaten 50, P.O. Box 1870, 5005 Bergen, Norway
| | - Jostein Saltskår
- grid.10917.3e0000 0004 0427 3161Institute of Marine Research (IMR), Fish Capture Division, Nordnes. NO-5817, Nordnesgaten 50, P.O. Box 1870, 5005 Bergen, Norway
| | - Erik Schuster
- grid.10917.3e0000 0004 0427 3161Institute of Marine Research (IMR), Fish Capture Division, Nordnes. NO-5817, Nordnesgaten 50, P.O. Box 1870, 5005 Bergen, Norway
| | - Maria Tenningen
- grid.10917.3e0000 0004 0427 3161Institute of Marine Research (IMR), Fish Capture Division, Nordnes. NO-5817, Nordnesgaten 50, P.O. Box 1870, 5005 Bergen, Norway
| | - Bjørn Totland
- grid.10917.3e0000 0004 0427 3161Institute of Marine Research (IMR), Fish Capture Division, Nordnes. NO-5817, Nordnesgaten 50, P.O. Box 1870, 5005 Bergen, Norway
| | - Aud Vold
- grid.10917.3e0000 0004 0427 3161Institute of Marine Research (IMR), Fish Capture Division, Nordnes. NO-5817, Nordnesgaten 50, P.O. Box 1870, 5005 Bergen, Norway
| | - Jan Tore Øvredal
- grid.10917.3e0000 0004 0427 3161Institute of Marine Research (IMR), Fish Capture Division, Nordnes. NO-5817, Nordnesgaten 50, P.O. Box 1870, 5005 Bergen, Norway
| | - Mike Breen
- grid.10917.3e0000 0004 0427 3161Institute of Marine Research (IMR), Fish Capture Division, Nordnes. NO-5817, Nordnesgaten 50, P.O. Box 1870, 5005 Bergen, Norway
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18
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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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19
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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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20
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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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21
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Rosenfeld J, Lee R. Thresholds for Reduction in Fish Growth and Consumption Due to Hypoxia: Implications for Water Quality Guidelines to Protect Aquatic Life. ENVIRONMENTAL MANAGEMENT 2022; 70:431-447. [PMID: 35792915 DOI: 10.1007/s00267-022-01678-9] [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: 03/22/2022] [Accepted: 06/23/2022] [Indexed: 06/15/2023]
Abstract
Control of hypoxia is a key element of water quality management, and guidelines are usually based on qualitative reviews of hypoxia impacts. In this study we use segmented regression to identify both thresholds for growth reduction and rate of decline of fish growth and food consumption under hypoxia; and then evaluate whether current freshwater guidelines for dissolved oxygen based on qualitative reviews are consistent with the quantitative analysis of hypoxia thresholds. Segmented regressions were fit to data from published growth-hypoxia studies for freshwater (N = 17) and marine fishes (N = 13). To understand potential drivers of hypoxia tolerance, we also modelled thresholds as simple functions of environmental and ecological covariates for each species including trophic level, marine vs. freshwater environment, maximum fish length, fish weight, and maximum temperature tolerance. The average threshold for growth reduction (Gcrit; 5.1 mg·l-1 DO) and decreased food consumption (Ccrit = 5.6 mg·l-1 DO) were not significantly different, and did not differ between marine and freshwater taxa. However, salmonids showed a significantly steeper decline in growth with increasing hypoxia relative to other taxa. Growth declined by 22% for every mg·l-1 reduction in DO below average Gcrit, and significant regressions indicate that warmwater (R2 = 0.25) and smaller-bodied (R2 = 0.44) species are more likely to be hypoxia tolerant. Observed mean Gcrit and Ccrit in the range of 5-6 mg·l-1 broadly match minimum water quality guidelines for the protection of aquatic life in freshwater in representative industrialized countries. However, this is much higher than the definition of hypoxia typically used in marine systems (2-2.5 mg·l-1), indicating a need to reconcile definition of hypoxia in the marine environment with empirical data. The principal challenge in freshwater hypoxia management is now translating discretionary guidelines into effective regulatory frameworks to reduce the incidence and severity of hypoxia.
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Affiliation(s)
- Jordan Rosenfeld
- British Columbian Ministry of the Environment and University of British Columbia Institute for the Oceans and Fisheries, University of British Columbia, 2202 Main Mall, Vancouver, BC, V6T 1Z4, Canada.
| | - Rachel Lee
- J.O. Thomas and Associates Ltd., 1370 Kootenay Street, Vancouver, BC, V5K 4R1, Canada
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22
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De Angelis CF, Soares MP, Cardoso IL, Filogonio R, Taylor EW, McKenzie DJ, Souza IC, Wunderlin DA, Monferrán MV, Fernandes MN, Leite CAC. Settleable atmospheric particulate matter affects cardiorespiratory responses to hypoxia in Nile tilapia (Oreochromis niloticus). Comp Biochem Physiol C Toxicol Pharmacol 2022; 257:109353. [PMID: 35452846 DOI: 10.1016/j.cbpc.2022.109353] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Revised: 03/28/2022] [Accepted: 04/14/2022] [Indexed: 11/03/2022]
Abstract
Atmospheric particulate matter (APM) emitted by iron ore processing industries has a complex composition, including diverse metallic particles and nanoparticles. Settleable APM (SePM) causes air to water cross-contamination and has recently been demonstrated to have harmful sublethal impacts on fish, eliciting stress responses, affecting the immune system, and reducing blood oxygen-carrying capacity. These findings imply potential consequences for fish aerobic performance and energy allocation, particularly in their ability to tolerate respiratory challenges such as aquatic hypoxia. To assess that potential limitation, we analyzed metabolic, cardiorespiratory, and morphological alterations after exposing tilapia, Oreochromis niloticus, to an environmentally relevant concentration of SePM (96 h) and progressive hypoxia. The contamination initiated detectable gill damage, reducing respiratory efficiency, increasing ventilatory effort, and compromising fish capacity to deal with hypoxia. Even in normoxia, the resting respiratory frequency was elevated and limited respiratory adjustments during hypoxia. SePM increased O2crit from 26 to 34% of O2 (1.84 to 2.76 mg O2·L-1). Such ventilatory inefficacy implies higher ventilatory cost with relevant alterations in energy allocation. Progression in gill damage might be problematic and cause: infection, blood loss, ion imbalance, and limited cardiorespiratory performance. The contamination did not cause immediate lethality but may threaten fish populations due to limitations in physiological performance. This was the first investigation to evaluate the physiological responses of fish to hypoxia after SePM contamination. We suggest that the present level of environmental SePM deserves attention. The present results demonstrate the need for comprehensive studies on SePM effects in aquatic fauna.
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Affiliation(s)
- C F De Angelis
- Department of Physiological Sciences Department, Federal University of São Carlos, Rod Washington Luis km 235, 13565-905 São Carlos, SP, Brazil.
| | - M P Soares
- Department of Physiological Sciences Department, Federal University of São Carlos, Rod Washington Luis km 235, 13565-905 São Carlos, SP, Brazil
| | - I L Cardoso
- Department of Physiological Sciences Department, Federal University of São Carlos, Rod Washington Luis km 235, 13565-905 São Carlos, SP, Brazil
| | - R Filogonio
- Department of Physiological Sciences Department, Federal University of São Carlos, Rod Washington Luis km 235, 13565-905 São Carlos, SP, Brazil
| | - E W Taylor
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - D J McKenzie
- MARBEC, Université de Montpellier, CNRS, Ifremer, IRD, Montpellier 34095, France.
| | - I C Souza
- Department of Physiological Sciences Department, Federal University of São Carlos, Rod Washington Luis km 235, 13565-905 São Carlos, SP, Brazil.
| | - D A Wunderlin
- ICYTAC: Instituto de Ciencia y Tecnología de Alimentos Córdoba, CONICET, Departmento de Química Orgánica, Universidad Nacional de Córdoba, Bv. Medina Allende s/n, Ciudad Universitaria, 5000 Córdoba, Argentina
| | - M V Monferrán
- ICYTAC: Instituto de Ciencia y Tecnología de Alimentos Córdoba, CONICET, Departmento de Química Orgánica, Universidad Nacional de Córdoba, Bv. Medina Allende s/n, Ciudad Universitaria, 5000 Córdoba, Argentina.
| | - M N Fernandes
- Department of Physiological Sciences Department, Federal University of São Carlos, Rod Washington Luis km 235, 13565-905 São Carlos, SP, Brazil.
| | - C A C Leite
- Department of Physiological Sciences Department, Federal University of São Carlos, Rod Washington Luis km 235, 13565-905 São Carlos, SP, Brazil.
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23
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Hughes DJ, Alexander J, Cobbs G, Kühl M, Cooney C, Pernice M, Varkey D, Voolstra CR, Suggett DJ. Widespread oxyregulation in tropical corals under hypoxia. MARINE POLLUTION BULLETIN 2022; 179:113722. [PMID: 35537305 DOI: 10.1016/j.marpolbul.2022.113722] [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: 10/26/2021] [Revised: 04/12/2022] [Accepted: 04/30/2022] [Indexed: 06/14/2023]
Abstract
Hypoxia (low oxygen stress) is increasingly reported on coral reefs, caused by ocean deoxygenation linked to coastal nutrient pollution and ocean warming. While the ability to regulate respiration is a key driver of hypoxia tolerance in many other aquatic taxa, corals' oxyregulatory capabilities remain virtually unexplored. Here, we examine O2-consumption patterns across 17 coral species under declining O2 partial pressure (pO2). All corals showed ability to oxyregulate, but total positive regulation (Tpos) varied between species, ranging from 0.41 (Pocillopora damicornis) to 2.42 (P. acuta). On average, corals performed maximum regulation effort (Pcmax) at low pO2 (30% air saturation, corresponding to lower O2 levels measured on natural reef systems), and exhibited detectable regulation down to as low as <10% air saturation. Our study shows that corals are not oxyconformers as previously thought, suggesting oxyregulation is likely important for survival in dynamic O2 environments of shallow coral reefs subjected to hypoxic events.
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Affiliation(s)
- David J Hughes
- University of Technology Sydney, Climate Change Cluster, Ultimo, NSW 2007, Australia.
| | - James Alexander
- Department of Biology, University of Louisville, Louisville, KY 40292, USA
| | - Gary Cobbs
- Department of Biology, University of Louisville, Louisville, KY 40292, USA
| | - Michael Kühl
- Marine Biology Section, Department of Biology, University of Copenhagen, Strandpromenaden 5, DK 3000 Helsingør, Denmark
| | - Chris Cooney
- University of Technology Sydney, Climate Change Cluster, Ultimo, NSW 2007, Australia
| | - Mathieu Pernice
- University of Technology Sydney, Climate Change Cluster, Ultimo, NSW 2007, Australia
| | - Deepa Varkey
- Department of Molecular Sciences, Macquarie University, NSW 2109, Australia
| | | | - David J Suggett
- University of Technology Sydney, Climate Change Cluster, Ultimo, NSW 2007, Australia
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24
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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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25
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Vazquez Roman KN, Burggren WW. Metabolic responses to crude oil during early life stages reveal critical developmental windows in the zebrafish (Danio rerio). Comp Biochem Physiol C Toxicol Pharmacol 2022; 254:109274. [PMID: 35051628 DOI: 10.1016/j.cbpc.2022.109274] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Revised: 12/07/2021] [Accepted: 01/12/2022] [Indexed: 11/03/2022]
Abstract
Morphological effects of crude oil exposure on early development in fishes have been well documented, but crude oil's metabolic effects and when in early development these effects might be most prominent remains unclear. We hypothesized that zebrafish (Danio rerio) exposed to crude oil as a high energy water accommodated fraction (HEWAF) would show increased routine oxygen consumption (ṀO2) and critical oxygen tension (PCrit) and this effect would be dependent upon day of HEWAF exposure, revealing critical windows of development for exposure effects. Zebrafish were exposed to 0%, 10%, 25%, 50% or 100% HEWAF for 24 h during one of the first six days post-fertilization (dpf). Survival rate, body mass, routine ṀO2, and PCrit were then measured at 7 dpf. Survival rate and especially body mass were both decreased based on both exposure concentration and day of crude oil exposure, with the largest decrease when HEWAF exposure occurred at 3 dpf. HEWAF effects on routine ṀO2 also differed depending upon exposure day. The largest effect occurred at 3 dpf, when ṀO2 increased significantly by ~60% from 10.1 ± 0.8 μmol O2/g/h compared to control group value of 6.3 ± 0.4 μmol O2/g/h. No significant effects of HEWAF exposure on any day were evident for PCrit (85 ± 4 mmHg in the control population). Overall, the main effects on body mass and ṀO2 measured at 7 dpf occurred when HEWAF exposures occurred at ~3 dpf. This critical window for metabolism in zebrafish larvae coincides with time of hatching, which may represent an especially vulnerable period in development.
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Affiliation(s)
- Karem N Vazquez Roman
- Developmental Integrative Biology Research Group, Department of Biological Sciences, University of North Texas, Denton, TX, USA.
| | - Warren W Burggren
- Developmental Integrative Biology Research Group, Department of Biological Sciences, University of North Texas, Denton, TX, USA
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26
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Harter TS, Damsgaard C, Regan MD. Linking environmental salinity to respiratory phenotypes and metabolic rate in fishes: a data mining and modelling approach. J Exp Biol 2022; 225:274262. [PMID: 35258603 DOI: 10.1242/jeb.243421] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The gill is the primary site of ionoregulation and gas exchange in adult teleost fishes. However, those characteristics that benefit diffusive gas exchange (large, thin gills) may also enhance the passive equilibration of ions and water that threaten osmotic homeostasis. Our literature review revealed that gill surface area and thickness were similar in freshwater (FW) and seawater (SW) species; however, the diffusive oxygen (O2) conductance (Gd) of the gill was lower in FW species. While a lower Gd may reduce ion losses, it also limits O2 uptake capacity and possibly aerobic performance in situations of high O2 demand (e.g. exercise) or low O2 availability (e.g. environmental hypoxia). We also found that FW fishes had significantly higher haemoglobin (Hb)-O2 binding affinities than SW species, which will increase the O2 diffusion gradient across the gills. Therefore, we hypothesized that the higher Hb-O2 affinity of FW fishes compensates, in part, for their lower Gd. Using a combined literature review and modelling approach, our results show that a higher Hb-O2 affinity in FW fishes increases the flux of O2 across their low-Gd gills. In addition, FW and SW teleosts can achieve similar maximal rates of O2 consumption (ṀO2,max) and hypoxia tolerance (Pcrit) through different combinations of Hb-O2 affinity and Gd. Our combined data identified novel patterns in gill and Hb characteristics between FW and SW fishes and our modelling approach provides mechanistic insight into the relationship between aerobic performance and species distribution ranges, generating novel hypotheses at the intersection of cardiorespiratory and ionoregulatory fish physiology.
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Affiliation(s)
- Till S Harter
- Marine Biology Research Division, Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA 92093, USA
| | - Christian Damsgaard
- Zoophysiology, Department of Biology, Aarhus University, 8000 Aarhus, Denmark.,Aarhus Institute of Advanced Studies, Aarhus University, 8000 Aarhus, Denmark
| | - Matthew D Regan
- Département de sciences biologiques, Université de Montréal, Montreal, QC, Canada, H3T 1J4
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27
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Cochran JK, Orr SE, Buchwalter DB. Assessing the P crit in relation to temperature and the expression of hypoxia associated genes in the mayfly, Neocloeon triangulifer. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 808:151743. [PMID: 34826479 DOI: 10.1016/j.scitotenv.2021.151743] [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: 09/27/2021] [Revised: 11/08/2021] [Accepted: 11/13/2021] [Indexed: 06/13/2023]
Abstract
Hypoxia is a growing concern in aquatic ecosystems. Historically, scientists have used the Pcrit (the dissolved oxygen level below which an animal can no longer oxyregulate) to infer hypoxia tolerance across species. Here, we tested the hypothesis that the Pcrit is positively correlated with temperature in the mayfly, Neocloeon triangulifer. Cross-temperature comparisons showed a modest (r = 0.47), but significant (p < 0.0001) association between temperature and Pcrit despite relatively large interindividual variability (Coefficient of Variance (CV) = 39.9% at 18 °C). We used the expression of hypoxia-responsive genes EGL-9 (an oxygen sensing gene and modulator of HIF-1a activity) and LDH (a hypoxia indicator) to test whether oxygen partial pressure near the Pcrit stimulates expression of hypoxia-responsive genes. Neither gene was upregulated at oxygen levels above the estimated Pcrit, however, at or below the Pcrit estimates, expression of both genes was stimulated (~20- and ~3-fold change for EGL-9 and LDH, respectively). Finally, we evaluated the influence of hypoxic exposure time and pretreatment conditions on the mRNA expression levels of hypoxia-responsive genes. When larvae were exposed to a gradual reduction of DO, hypoxic gene expression was more robust than during instantaneous exposure to hypoxia. Our data provide modest support for traditional interpretation of the Pcrit as a physiologically meaningful shift from aerobic to anaerobic metabolism in N. triangulifer. However, we also discuss limitations of the Pcrit as a proxy measure of hypoxia tolerance at the species level.
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Affiliation(s)
- Jamie K Cochran
- Department of Biological Sciences, North Carolina State University, Raleigh, NC 27695, United States of America
| | - Sarah E Orr
- Department of Biological Sciences, North Carolina State University, Raleigh, NC 27695, United States of America
| | - David B Buchwalter
- Department of Biological Sciences, North Carolina State University, Raleigh, NC 27695, United States of America.
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28
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Monteiro DA, Kalinin AL, Rantin FT, McKenzie DJ. Use of complex physiological traits as ecotoxicological biomarkers in tropical freshwater fishes. JOURNAL OF EXPERIMENTAL ZOOLOGY. PART A, ECOLOGICAL AND INTEGRATIVE PHYSIOLOGY 2021; 335:745-760. [PMID: 34529366 DOI: 10.1002/jez.2540] [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: 03/31/2021] [Revised: 07/21/2021] [Accepted: 08/02/2021] [Indexed: 06/13/2023]
Abstract
We review the use of complex physiological traits, of tolerance and performance, as biomarkers of the toxicological effects of contaminants in subtropical and tropical freshwater fishes. Such traits are growing in relevance due to climate change, as exposure to contaminants may influence the capacity of fishes to tolerate and perform in an increasingly stressful environment. We review the evidence that the critical oxygen level, a measure of hypoxia tolerance, provides a valuable biomarker of impacts of diverse classes of contaminants. When coupled with measures of cardiorespiratory variables, it can provide insight into mechanisms of toxicity. The critical thermal maximum, a simple measure of tolerance of acute warming, also provides a valuable biomarker despite a lack of understanding of its mechanistic basis. Its relative ease of application renders it useful in the rapid evaluation of multiple species, and in understanding how the severity of contaminant impacts depends upon prevailing environmental temperature. The critical swimming speed is a measure of exercise performance that is widely used as a biomarker in temperate species but very few studies have been performed on subtropical or tropical fishes. Overall, the review serves to highlight a critical lack of knowledge for subtropical and tropical freshwater fishes. There is a real need to expand the knowledge base and to use physiological biomarkers in support of decision making to manage tropical freshwater fish populations and their habitats, which sustain rich biodiversity but are under relentless anthropogenic pressure.
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Affiliation(s)
- Diana A Monteiro
- Department of Physiological Sciences, Federal University of São Carlos (UFSCar), São Carlos, São Paulo, Brazil
| | - Ana L Kalinin
- Department of Physiological Sciences, Federal University of São Carlos (UFSCar), São Carlos, São Paulo, Brazil
| | - F Tadeu Rantin
- Department of Physiological Sciences, Federal University of São Carlos (UFSCar), São Carlos, São Paulo, Brazil
| | - David J McKenzie
- Department of Physiological Sciences, Federal University of São Carlos (UFSCar), São Carlos, São Paulo, Brazil
- UMR Marbec, Univ. Montpellier, CNRS, IRD, Ifremer, Montpellier, France
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29
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Lau SC, Mehdi H, Bragg LM, Servos MR, Balshine S, Scott GR. Exposure to wastewater effluent disrupts hypoxia responses in killifish (Fundulus heteroclitus). ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2021; 284:117373. [PMID: 34077896 DOI: 10.1016/j.envpol.2021.117373] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Revised: 05/05/2021] [Accepted: 05/12/2021] [Indexed: 06/12/2023]
Abstract
Hypoxia (low oxygen) often occurs in aquatic ecosystems that receive effluent from municipal wastewater treatment plants (WWTP). The combination of hypoxia and WWTP effluent could impair fish health, because WWTP effluent contains multiple contaminants that could disrupt the physiological pathways fish use to cope with hypoxia, but the interactive effects of these stressors on fish physiology are poorly understood. We have examined this issue by exposing mummichog killifish (Fundulus heteroclitus) to hypoxia (5 and 2 kPa O2) and/or 100% WWTP effluent for 21 days in a full factorial design. We then measured hypoxia tolerance, whole-animal metabolism, gill morphology, haematology, and tissue metabolites. In clean water, killifish responded to chronic hypoxia with improvements in hypoxia tolerance, as reflected by increases in time to loss of equilibrium at 0.5 kPa (tLOE). These improvements occurred in association with increases in the exposed surface of gill lamellae that resulted from a regression of interlamellar cell mass (ILCM). Concurrent exposure to wastewater attenuated the increases in tLOE and gill remodeling in chronic hypoxia, and nearly depleted brain glycogen stores. Therefore, exposure to WWTP effluent can disrupt the physiological mechanisms fish use to cope with chronic hypoxia and impair hypoxia tolerance. Our research suggests that the combination of stressors near WWTPs can have interactive effects on the physiology and health of fish.
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Affiliation(s)
- Samantha C Lau
- Department of Biology, McMaster University, 1280 Main Street West, Hamilton, ON, L8S 4K1, Canada
| | - Hossein Mehdi
- Department of Psychology, Neuroscience, and Behaviour, McMaster University, 1280 Main Street West, Hamilton, ON, L8S 4K1, Canada
| | - Leslie M Bragg
- Department of Biology, University of Waterloo, 200 University Ave. W, Waterloo, ON, N2L 3G1, Canada
| | - Mark R Servos
- Department of Biology, University of Waterloo, 200 University Ave. W, Waterloo, ON, N2L 3G1, Canada
| | - Sigal Balshine
- Department of Psychology, Neuroscience, and Behaviour, McMaster University, 1280 Main Street West, Hamilton, ON, L8S 4K1, Canada
| | - Graham R Scott
- Department of Biology, McMaster University, 1280 Main Street West, Hamilton, ON, L8S 4K1, Canada.
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30
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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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31
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Transcriptomic profiling of Gh/Igf system reveals a prompted tissue-specific differentiation and novel hypoxia responsive genes in gilthead sea bream. Sci Rep 2021; 11:16466. [PMID: 34385497 PMCID: PMC8360970 DOI: 10.1038/s41598-021-95408-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Accepted: 07/19/2021] [Indexed: 12/16/2022] Open
Abstract
A customized PCR-array was used for the simultaneous gene expression of the Gh/Igf system and related markers of muscle growth, and lipid and energy metabolism during early life stages of gilthead sea bream (60–127 days posthatching). Also, transcriptional reprogramming by mild hypoxia was assessed in fingerling fish with different history trajectories on O2 availability during the same time window. In normoxic fish, the expression of almost all the genes in the array varied over time with a prompted liver and muscle tissue-specific differentiation, which also revealed temporal changes in the relative expression of markers of the full gilthead sea bream repertoire of Gh receptors, Igfs and Igf-binding proteins. Results supported a different contribution through development of ghr and igf subtypes on the type of action of GH via systemic or direct effects at the local tissue level. This was extensive to Igfbp1/2/4 and Igfbp3/5/6 clades that clearly evolved through development as hepatic and muscle Igfbp subtypes, respectively. This trade-off is however very plastic to cope changes in the environment, and ghr1 and igfbp1/3/4/5 emerged as hypoxic imprinting genes during critical early developmental windows leading to recognize individuals with different history trajectories of oxygen availability and metabolic capabilities later in life.
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32
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Braz-Mota S, Almeida-Val VMF. Ecological adaptations of Amazonian fishes acquired during evolution under environmental variations in dissolved oxygen: A review of responses to hypoxia in fishes, featuring the hypoxia-tolerant Astronotus spp. JOURNAL OF EXPERIMENTAL ZOOLOGY PART 2021; 335:771-786. [PMID: 34338442 DOI: 10.1002/jez.2531] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Revised: 06/25/2021] [Accepted: 07/12/2021] [Indexed: 11/06/2022]
Abstract
The Amazon Basin presents a dynamic regime of dissolved oxygen (DO) oscillations, which varies among habitats within the basin, including spatially, daily, and seasonally. Fish species inhabiting these environments have developed many physiological adaptations to deal with the frequent and periodic events of low (hypoxia), or no (anoxia) DO in the water. Cichlid fishes, especially the genus Astronotus (A. ocellatus and A. crassipinnis), are hypoxic-tolerant species that can survive in very low DO levels for long periods, while adults often inhabit places where DO is close to zero. The present review will focus on some metabolic adjustments that Amazonian fish use in response to hypoxic conditions, which include many strategies from behavioral, morphological, physiological, and biochemical strategies. These strategies include ASR (aerial surface respiration), lip expansion, branchial tissue remodeling, increases in glycolytic metabolism with the increase of blood glucose levels, and increases in anaerobic metabolism with increases of plasma lactate levels. Other groups over evolutionary time developed obligate aerial respiration with changes in pharyngeal and swim bladder vascularization as well as the development of a true lung. However, most species are water-breathing species, such as A. ocellatus and A. crassipinnis, which are detailed in this study because they are used as hypoxia-tolerant model fish. Herein, we draw together the literature data of the physiological mechanisms by which these species decrease aerobic metabolism and increase anaerobic metabolism to survive hypoxia. This is the first attempt to synthesize the physiological mechanisms of the hypoxia-tolerant Astronotus species.
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Affiliation(s)
- Susana Braz-Mota
- Laboratory of Ecophysiology and Molecular Evolution, Brazilian National Institute for Research in the Amazon, Manaus, Amazonas, Brazil
| | - Vera M F Almeida-Val
- Laboratory of Ecophysiology and Molecular Evolution, Brazilian National Institute for Research in the Amazon, Manaus, Amazonas, Brazil
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33
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Schäfer N, Matoušek J, Rebl A, Stejskal V, Brunner RM, Goldammer T, Verleih M, Korytář T. Effects of Chronic Hypoxia on the Immune Status of Pikeperch ( Sander lucioperca Linnaeus, 1758). BIOLOGY 2021; 10:biology10070649. [PMID: 34356504 PMCID: PMC8301350 DOI: 10.3390/biology10070649] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 06/28/2021] [Accepted: 07/07/2021] [Indexed: 01/16/2023]
Abstract
Simple Summary Inadequate oxygen saturation, or hypoxia, belongs to one of the critical stress factors in intensive aquaculture. Exposure of fish to low oxygen levels over prolonged periods substantially affects their well-being and immune competence, resulting in increased disease susceptibility and consequent economic losses. In this interdisciplinary research, we aimed to provide a deeper understanding of the effect of chronic low oxygen saturation on pikeperch farmed in recirculating aquaculture systems. The obtained data offer unprecedented insights into the changes in the immunocompetence of studied fish and suggest high robustness of this new aquaculture species to the stress factors of intensive aquaculture. Abstract Inadequate oxygen saturation can induce stress responses in fish and further affect their immunity. Pikeperch, recently introduced in intensive aquaculture, is suggested to be reared at nearly 100% DO (dissolved oxygen), yet this recommendation can be compromised by several factors including the water temperature, stocking densities or low circulation. Herein, we aimed to investigate the effect of low oxygen saturation of 40% DO (±3.2 mg/L) over 28 days on pikeperch farmed in recirculating aquaculture systems. The obtained data suggest that—although the standard blood and health parameters did not reveal any significant differences at any timepoint—the flow cytometric analysis identified a slightly decreased proportion of lymphocytes in the HK (head kidney) of fish exposed to hypoxia. This has been complemented by marginally downregulated expression of investigated immune and stress genes in HK and liver (including FTH1, HIF1A and NR3C1). Additionally, in the model of acute peritoneal inflammation induced with inactivated Aeromonas hydrophila, we observed a striking dichotomy in the sensitivity to the low DO between innate and adaptive immunity. Thus, while the mobilization of myeloid cells from HK to blood, spleen and peritoneal cavity, underlined by changes in the expression of key proinflammatory cytokines (including MPO, IL1B and TNF) was not influenced by the low DO, hypoxia impaired the influx of lymphocytes to the peritoneal niche in the later phases of the immune reaction. Taken together, our data suggest high robustness of pikeperch towards the low oxygen saturation and further encourage its introduction to the intensive aquaculture systems.
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Affiliation(s)
- Nadine Schäfer
- Fish Genetics Unit, Institute of Genome Biology, Leibniz Institute for Farm Animal Biology (FBN), 18196 Dummerstorf, Germany; (N.S.); (A.R.); (R.M.B.); (T.G.)
| | - Jan Matoušek
- Institute of Aquaculture and Protection of Waters (IAPW), Faculty of Fisheries and Protection of Waters, University of South Bohemia, 370 05 České Budějovice, Czech Republic; (J.M.); (V.S.)
| | - Alexander Rebl
- Fish Genetics Unit, Institute of Genome Biology, Leibniz Institute for Farm Animal Biology (FBN), 18196 Dummerstorf, Germany; (N.S.); (A.R.); (R.M.B.); (T.G.)
| | - Vlastimil Stejskal
- Institute of Aquaculture and Protection of Waters (IAPW), Faculty of Fisheries and Protection of Waters, University of South Bohemia, 370 05 České Budějovice, Czech Republic; (J.M.); (V.S.)
| | - Ronald M. Brunner
- Fish Genetics Unit, Institute of Genome Biology, Leibniz Institute for Farm Animal Biology (FBN), 18196 Dummerstorf, Germany; (N.S.); (A.R.); (R.M.B.); (T.G.)
| | - Tom Goldammer
- Fish Genetics Unit, Institute of Genome Biology, Leibniz Institute for Farm Animal Biology (FBN), 18196 Dummerstorf, Germany; (N.S.); (A.R.); (R.M.B.); (T.G.)
- Molecular Biology and Fish Genetics, Faculty of Agriculture and Environmental Sciences, University of Rostock, 18059 Rostock, Germany
| | - Marieke Verleih
- Fish Genetics Unit, Institute of Genome Biology, Leibniz Institute for Farm Animal Biology (FBN), 18196 Dummerstorf, Germany; (N.S.); (A.R.); (R.M.B.); (T.G.)
- Correspondence: (M.V.); (T.K.); Tel.: +49-38208-68-721 (M.V.); +420-387-775-471 (T.K.)
| | - Tomáš Korytář
- Institute of Aquaculture and Protection of Waters (IAPW), Faculty of Fisheries and Protection of Waters, University of South Bohemia, 370 05 České Budějovice, Czech Republic; (J.M.); (V.S.)
- Institute of Parasitology, Biology Centre CAS, 370 05 České Budějovice, Czech Republic
- Correspondence: (M.V.); (T.K.); Tel.: +49-38208-68-721 (M.V.); +420-387-775-471 (T.K.)
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Pang X, Pu DY, Xia DY, Liu XH, Ding SH, Li Y, Fu SJ. Individual variation in metabolic rate, locomotion capacity and hypoxia tolerance and their relationships in juveniles of three freshwater fish species. J Comp Physiol B 2021; 191:755-764. [PMID: 34091751 DOI: 10.1007/s00360-021-01382-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2021] [Revised: 05/09/2021] [Accepted: 05/27/2021] [Indexed: 11/24/2022]
Abstract
Individual variations in metabolic rate, locomotion capacity and hypoxia tolerance and their relationships were investigated in three cyprinid species [crucian carp (Carassius auratus), common carp (Cyprinus carpio) and qingbo (Spinibarbus sinensis), in 60 individuals of each species]. Either the active metabolic rate (AMR) and critical swimming speed (Ucrit) (30 individuals) or critical oxygen tension (Pcrit) and loss of equilibrium (LOE) (30 individuals) were measured in each species after measuring the resting metabolic rate (RMR). Both the AMR and Ucrit were found to be significantly and positively correlated with the RMR in all three cyprinid species, indicating that high-RMR individuals have high aerobic capacity and thus good swimming performance. Pcrit was positively correlated with the RMR in all three species, whereas the LOE was highly positively correlated, weakly positively correlated and not correlated with the RMR in qingbo, common carp and crucian carp, respectively, possibly due to specialized morphological and biochemical adaptations involved in hypoxia tolerance in crucian and common carp. Crucian carp showed relatively poor swimming performance, i.e., a low Ucrit (relatively high variation), strong hypoxia tolerance, and low LOE (relatively low variation); qingbo showed relatively good swimming performance (relatively low variation) and weak hypoxia tolerance (relatively high variation); and common carp showed moderate swimming performance and relatively strong hypoxia tolerance (moderate variation). These interspecific differences may be due to the different lifestyles of these cyprinid fishes based on their associated fast-slow-flow regime and are outcomes of long-term selection.
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Affiliation(s)
- Xu Pang
- College of Fisheries, Institute of Three Gorges Ecological Fisheries of Chongqing, Southwest University, Chongqing, 400715, China
- Key Laboratory of Freshwater Fish Reproduction and Development, Education of Ministry, Key Laboratory of Aquatic Science of Chongqing, Southwest University, Chongqing, 400715, China
| | - De-Yong Pu
- Key Laboratory of Freshwater Fish Reproduction and Development, Education of Ministry, Key Laboratory of Aquatic Science of Chongqing, Southwest University, Chongqing, 400715, China
| | - Dan-Yang Xia
- Key Laboratory of Freshwater Fish Reproduction and Development, Education of Ministry, Key Laboratory of Aquatic Science of Chongqing, Southwest University, Chongqing, 400715, China
| | - Xiao-Hong Liu
- Key Laboratory of Freshwater Fish Reproduction and Development, Education of Ministry, Key Laboratory of Aquatic Science of Chongqing, Southwest University, Chongqing, 400715, China
| | - Shi-Hua Ding
- College of Fisheries, Institute of Three Gorges Ecological Fisheries of Chongqing, Southwest University, Chongqing, 400715, China
- Key Laboratory of Freshwater Fish Reproduction and Development, Education of Ministry, Key Laboratory of Aquatic Science of Chongqing, Southwest University, Chongqing, 400715, China
| | - Yun Li
- College of Fisheries, Institute of Three Gorges Ecological Fisheries of Chongqing, Southwest University, Chongqing, 400715, China
- Key Laboratory of Freshwater Fish Reproduction and Development, Education of Ministry, Key Laboratory of Aquatic Science of Chongqing, Southwest University, Chongqing, 400715, China
| | - Shi-Jian Fu
- Laboratory of Evolutionary Physiology and Behaviour, Chongqing Normal University, Chongqing, 401331, China.
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35
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Unger S, Goforth R, Rhodes O, Floyd T. Short-term exposure to elevated suspended sediment increases oxygen uptake of gilled larval Eastern Hellbender ( Cryptobranchus alleganiensis) salamanders. CAN J ZOOL 2021. [DOI: 10.1139/cjz-2020-0085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Freshwater ecosystems are increasingly impacted by anthropogenic elevated levels of suspended sediment that may negatively affect aquatic organisms, including salamanders. Although increasing fine sediment in streams has been suggested as a reason for population declines, to date no study has empirically assessed the effect of suspended sediment on gilled larval Eastern Hellbenders (Cryptobranchus alleganiensis (Sonnini de Manoncourt and Latreille, 1801)), a critical life-history stage and a species of conservation concern. We used custom respirometers to elucidate effects of suspended sediments on larval Eastern Hellbender oxygen uptake in trials conducted in situ in Georgia (USA) streams. Mean oxygen uptake increased and was significantly higher in trials when larval salamanders were exposed to suspended sediment (mean = 5.06 mg O2/L for 800 mg/L of sediment treatment vs. 2.25 mg O2/L for 0.00 mg/L of sediment control). This may indicate elevated physiological stress in response to short-term exposure to suspended sediments. Qualitatively, individuals in both groups exhibited rocking behavior in response to low oxygen (hypoxia), albeit at different frequencies (sediment exposure = 7.6 rocks/min and control = 2.1 rocks/min). Larval salamanders may be able to temporarily compensate for low oxygen through increased rocking behavior when high suspended sediment loads are present, with future respirometry research needed.
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Affiliation(s)
- S.D. Unger
- Biology Department, Bridges Science Building, Wingate University, Wingate, NC 28174, USA
| | - R.R. Goforth
- Department of Forestry and Natural Resources, Purdue University, 195 Marsteller Street, West Lafayette, IN 47907-2033, USA
| | - O.E. Rhodes
- Savannah River Ecology Laboratory, P.O. Drawer E, Aiken, SC 29802, USA
| | - T.M. Floyd
- Wildlife Resources Division, Wildlife Conservation Section, Georgia Department of Natural Resources, 116 Rum Creek Drive, Forsyth, GA 31029, USA
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36
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Toro-Chacon J, Tickell F, González R, Victoriano PF, Fernández-Urruzola I, Urbina MA. Aerobic and anaerobic metabolic scaling in the burrowing freshwater crayfish Parastacus pugnax. J Comp Physiol B 2021; 191:617-628. [PMID: 33948707 DOI: 10.1007/s00360-021-01374-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Revised: 04/02/2021] [Accepted: 04/20/2021] [Indexed: 12/01/2022]
Abstract
Metabolic scaling is a well-known biological pattern. Theoretical scaling exponents near 0.67 and 0.75 are the most widely accepted for aerobic metabolism, but little is known about the scaling of anaerobic metabolism. Furthermore, metabolic scaling has been mainly evaluated in organisms primarily relying on aerobic pathways. Here we evaluate both aerobic and anaerobic metabolic scaling in Parastacus pugnax, a burrowing freshwater crayfish endemic to Chile, which inhabits waters with low pO2 (~ 1 mg O2 L-1, measured in this study). We determined the metabolic rate, total oxidative capacity (Electron Transport System: ETS), critical oxygen tension (Pcrit) and muscular Lactate dehydrogenase (LHD) and Malate dehydrogenase (MDH) enzymatic activities (proxies of anaerobic metabolism) over a wide range of P. pugnax sizes (0.24-42.93 g wet mass). Aerobic metabolism scaled with crayfish size with an exponent of 0.78, remarkably similar to the 0.73 which scaled the ETS, the enzymatic complex behind respiration. Critical partial pressure of oxygen (Pcrit) was calculated as 15.6 ± 2.9 mmHg, showing that aerobic metabolism was efficiently maintained until ~ 10% air saturation. Below this threshold, P. pugnax switched to anaerobic metabolism, evidenced by a reduction in aerobic metabolism and ETS activity under chronic low oxygen conditions. None of the activities of MDH, LDH, their ratio (MDH/LDH), nor Pcrit scaled with crayfish size, indicating that these animals are equally adapted to hypoxic environments throughout their whole ontogeny. Given the particularities of its habitat, the information presented here is valuable for a proper management and successful conservation.
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Affiliation(s)
- Jorge Toro-Chacon
- Departamento de Zoología, Facultad de Ciencias Naturales y Oceanográficas, Universidad de Concepción, Casilla 160-C, Concepción, Chile
| | - Flora Tickell
- Departamento de Zoología, Facultad de Ciencias Naturales y Oceanográficas, Universidad de Concepción, Casilla 160-C, Concepción, Chile.,Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK
| | - Rodrigo González
- Departamento de Oceanografía, Facultad de Ciencias Naturales y Oceanográficas, Universidad de Concepción, Concepción, Chile.,Facultad de Ciencias Naturales y Oceanográficas, Centro de Investigación Oceanográfica COPAS Sur-Austral, Universidad de Concepción, Concepción, Chile
| | - Pedro F Victoriano
- Departamento de Zoología, Facultad de Ciencias Naturales y Oceanográficas, Universidad de Concepción, Casilla 160-C, Concepción, Chile
| | - Igor Fernández-Urruzola
- Instituto Milenio de Oceanografía (IMO), Universidad de Concepción, PO Box 1313, Concepción, Chile
| | - Mauricio A Urbina
- Departamento de Zoología, Facultad de Ciencias Naturales y Oceanográficas, Universidad de Concepción, Casilla 160-C, Concepción, Chile. .,Instituto Milenio de Oceanografía (IMO), Universidad de Concepción, PO Box 1313, Concepción, Chile.
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37
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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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38
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Morgenroth D, McArley T, Gräns A, Axelsson M, Sandblom E, Ekström A. Coronary blood flow influences tolerance to environmental extremes in fish. J Exp Biol 2021; 224:jeb.239970. [PMID: 33688058 DOI: 10.1242/jeb.239970] [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] [Received: 10/27/2020] [Accepted: 03/03/2021] [Indexed: 12/16/2022]
Abstract
Approximately half of all fishes have, in addition to the luminal venous O2 supply, a coronary circulation supplying the heart with fully oxygenated blood. Yet, it is not fully understood how coronary O2 delivery affects tolerance to environmental extremes such as warming and hypoxia. Hypoxia reduces arterial oxygenation, while warming increases overall tissue O2 demand. Thus, as both stressors are associated with reduced venous O2 supply to the heart, we hypothesised that coronary flow benefits hypoxia and warming tolerance. To test this hypothesis, we blocked coronary blood flow (via surgical coronary ligation) in rainbow trout (Oncorhynchus mykiss) and assessed how in vivo cardiorespiratory performance and whole-animal tolerance to acute hypoxia and warming was affected. While coronary ligation reduced routine stroke volume relative to trout with intact coronaries, cardiac output was maintained by an increase in heart rate. However, in hypoxia, coronary-ligated trout were unable to increase stroke volume to maintain cardiac output when bradycardia developed, which was associated with a slightly reduced hypoxia tolerance. Moreover, during acute warming, coronary ligation caused cardiac function to collapse at lower temperatures and reduced overall heat tolerance relative to trout with intact coronary arteries. We also found a positive relationship between individual hypoxia and heat tolerance across treatment groups, and tolerance to both environmental stressors was positively correlated with cardiac performance. Collectively, our findings show that coronary perfusion improves cardiac O2 supply and therefore cardiovascular function at environmental extremes, which benefits tolerance to natural and anthropogenically induced environmental perturbations.
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Affiliation(s)
- Daniel Morgenroth
- Department of Biological and Environmental Sciences, University of Gothenburg, PO Box 463, 405 30 Gothenburg, Sweden
| | - Tristan McArley
- Department of Biological and Environmental Sciences, University of Gothenburg, PO Box 463, 405 30 Gothenburg, Sweden
| | - Albin Gräns
- Department of Animal Environment and Health, Swedish University of Agricultural Sciences, 532 23 Skara, Sweden
| | - Michael Axelsson
- Department of Biological and Environmental Sciences, University of Gothenburg, PO Box 463, 405 30 Gothenburg, Sweden
| | - Erik Sandblom
- Department of Biological and Environmental Sciences, University of Gothenburg, PO Box 463, 405 30 Gothenburg, Sweden
| | - Andreas Ekström
- Department of Biological and Environmental Sciences, University of Gothenburg, PO Box 463, 405 30 Gothenburg, Sweden
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39
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Bergstedt JH, Pfalzgraff T, Skov PV. Hypoxia tolerance and metabolic coping strategies in Oreochromis niloticus. Comp Biochem Physiol A Mol Integr Physiol 2021; 257:110956. [PMID: 33857591 DOI: 10.1016/j.cbpa.2021.110956] [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: 01/05/2021] [Revised: 04/07/2021] [Accepted: 04/07/2021] [Indexed: 10/21/2022]
Abstract
The Nile tilapia (Oreochromis niloticus) is widely farmed in tropical and subtropical pond culture. O. niloticus is recognized as a species that is tolerant of hypoxic conditions, a trait that may largely be responsible for the success of this species in aquaculture. Until now, neither coping mechanisms nor a comparison of various indices of hypoxia tolerance to characterize the response to hypoxia, have been described. In the present study, Nile tilapia were subjected to hypoxia of increasing severity and duration to examine effects on metabolic rate (MO2) and post hypoxic oxygen debt. MO2 was measured during periods of severe hypoxia at 2.1 kPa O2 (10% oxygen saturation) lasting between 2 and 24 h at 27 °C. Hypoxia tolerance was assessed by determining the critical oxygen tension (Pcrit) and the pO2 at which loss of equilibrium (LOE) occurred. We show that the tolerance of Nile tilapia to severe hypoxia is largely achieved through a capacity for metabolic depression. Despite prolonged exposure to dissolved oxygen levels below Pcrit, the fish showed little excess post-hypoxic oxygen consumption (EPHOC) upon return to normoxic conditions. LOE did not occur until conditions became near-anoxic. Blood pH was not affected by severe hypoxia (2.1 kPa O2), but a significant acidosis occurred during LOE, accompanied by a significant elevation in lactate and glucose levels. The results from the present study indicate that Nile tilapia do not switch to anaerobic metabolism during hypoxia until pO2 falls below 2.1 kPa.
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Affiliation(s)
- Julie Hansen Bergstedt
- DTU Aqua, Technical University of Denmark, Section for Aquaculture, The North Sea Research Centre, DK-9850 Hirtshals, Denmark.
| | - Tilo Pfalzgraff
- DTU Aqua, Technical University of Denmark, Section for Aquaculture, The North Sea Research Centre, DK-9850 Hirtshals, Denmark
| | - Peter Vilhelm Skov
- DTU Aqua, Technical University of Denmark, Section for Aquaculture, The North Sea Research Centre, DK-9850 Hirtshals, Denmark
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40
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Rodgers EM, Opinion AGR, Gomez Isaza DF, Rašković B, Poleksić V, De Boeck G. Double whammy: Nitrate pollution heightens susceptibility to both hypoxia and heat in a freshwater salmonid. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 765:142777. [PMID: 33077222 DOI: 10.1016/j.scitotenv.2020.142777] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 09/28/2020] [Accepted: 09/29/2020] [Indexed: 06/11/2023]
Abstract
Species persistence in a changing world will depend on how they cope with co-occurring stressors. Stressors can interact in unanticipated ways, where exposure to one stressor may heighten or reduce resilience to another stressor. We examined how a leading threat to aquatic species, nitrate pollution, affects susceptibility to hypoxia and heat stress in a salmonid, the European grayling (Thymallus thymallus). Fish were exposed to nitrate pollution (0, 50 or 200 mg NO3- L-1) at two acclimation temperatures (18 °C or 22 °C) for eight weeks. Hypoxia- and heat-tolerance were subsequently assessed, and the gills of a subset of fish were sampled for histological analyses. Nitrate-exposed fish were significantly more susceptible to acute hypoxia at both acclimation temperatures. Similarly, in 18 °C- acclimated fish, exposure to 200 mg NO3- L- 1 caused a 1 °C decrease in heat tolerance (critical thermal maxima, CTMax). However, the opposite effect was observed in 22 °C-acclimated fish, where nitrate exposure increased heat tolerance by ~1 °C. Further, nitrate exposure induced some histopathological changes to the gills, which limit oxygen uptake. Our findings show that nitrate pollution can heighten the susceptibility of fish to additional threats in their habitat, but interactions are temperature dependent.
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Affiliation(s)
- Essie M Rodgers
- Systemic Physiological and Ecotoxicological Research (SPHERE), Department of Biology, University of Antwerp, Antwerp 2020, Belgium.
| | - April Grace R Opinion
- Systemic Physiological and Ecotoxicological Research (SPHERE), Department of Biology, University of Antwerp, Antwerp 2020, Belgium
| | - Daniel F Gomez Isaza
- School of Biological Science, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Božidar Rašković
- University of Belgrade, Faculty of Agriculture, Institute of Animal Science, 11080 Belgrade, Serbia
| | - Vesna Poleksić
- University of Belgrade, Faculty of Agriculture, Institute of Animal Science, 11080 Belgrade, Serbia
| | - Gudrun De Boeck
- Systemic Physiological and Ecotoxicological Research (SPHERE), Department of Biology, University of Antwerp, Antwerp 2020, Belgium
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41
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Ekström A, Sundell E, Morgenroth D, McArley T, Gårdmark A, Huss M, Sandblom E. Cardiorespiratory adjustments to chronic environmental warming improve hypoxia tolerance in European perch ( Perca fluviatilis). J Exp Biol 2021; 224:jeb.241554. [PMID: 33568442 DOI: 10.1242/jeb.241554] [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: 12/02/2020] [Accepted: 02/01/2021] [Indexed: 11/20/2022]
Abstract
Aquatic hypoxia will become increasingly prevalent in the future as a result of eutrophication combined with climate warming. While short-term warming typically constrains fish hypoxia tolerance, many fishes cope with warming by adjusting physiological traits through thermal acclimation. Yet, little is known about how such adjustments affect tolerance to hypoxia. We examined European perch (Perca fluviatilis) from the Biotest enclosure (23°C, Biotest population), a unique ∼1 km2 ecosystem artificially warmed by cooling water from a nuclear power plant, and an adjacent reference site (16-18°C, reference population). Specifically, we evaluated how acute and chronic warming affect routine oxygen consumption rate (Ṁ O2,routine) and cardiovascular performance in acute hypoxia, alongside assessment of the thermal acclimation of the aerobic contribution to hypoxia tolerance (critical O2 tension for Ṁ O2,routine: P crit) and absolute hypoxia tolerance (O2 tension at loss of equilibrium; P LOE). Chronic adjustments (possibly across lifetime or generations) alleviated energetic costs of warming in Biotest perch by depressing Ṁ O2,routine and cardiac output, and by increasing blood O2 carrying capacity relative to reference perch acutely warmed to 23°C. These adjustments were associated with improved maintenance of cardiovascular function and Ṁ O2,routine in hypoxia (i.e. reduced P crit). However, while P crit was only partially thermally compensated in Biotest perch, they had superior absolute hypoxia tolerance (i.e. lowest P LOE) relative to reference perch irrespective of temperature. We show that European perch can thermally adjust physiological traits to safeguard and even improve hypoxia tolerance during chronic environmental warming. This points to cautious optimism that eurythermal fish species may be resilient to the imposition of impaired hypoxia tolerance with climate warming.
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Affiliation(s)
- Andreas Ekström
- Department of Biological and Environmental Sciences, University of Gothenburg, 405 30 Gothenburg, Sweden
| | - Erika Sundell
- Department of Biological and Environmental Sciences, University of Gothenburg, 405 30 Gothenburg, Sweden
| | - Daniel Morgenroth
- Department of Biological and Environmental Sciences, University of Gothenburg, 405 30 Gothenburg, Sweden
| | - Tristan McArley
- Department of Biological and Environmental Sciences, University of Gothenburg, 405 30 Gothenburg, Sweden
| | - Anna Gårdmark
- Department of Aquatic Resources, Swedish University of Agricultural Sciences, 742 42 Öregrund, Sweden
| | - Magnus Huss
- Department of Aquatic Resources, Swedish University of Agricultural Sciences, 742 42 Öregrund, Sweden
| | - Erik Sandblom
- Department of Biological and Environmental Sciences, University of Gothenburg, 405 30 Gothenburg, Sweden
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42
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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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43
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Vedor M, Queiroz N, Mucientes G, Couto A, Costa ID, Santos AD, Vandeperre F, Fontes J, Afonso P, Rosa R, Humphries NE, Sims DW. Climate-driven deoxygenation elevates fishing vulnerability for the ocean's widest ranging shark. eLife 2021; 10:62508. [PMID: 33461659 PMCID: PMC7815312 DOI: 10.7554/elife.62508] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Accepted: 12/17/2020] [Indexed: 12/24/2022] Open
Abstract
Climate-driven expansions of ocean hypoxic zones are predicted to concentrate pelagic fish in oxygenated surface layers, but how expanding hypoxia and fisheries will interact to affect threatened pelagic sharks remains unknown. Here, analysis of satellite-tracked blue sharks and environmental modelling in the eastern tropical Atlantic oxygen minimum zone (OMZ) shows shark maximum dive depths decreased due to combined effects of decreasing dissolved oxygen (DO) at depth, high sea surface temperatures, and increased surface-layer net primary production. Multiple factors associated with climate-driven deoxygenation contributed to blue shark vertical habitat compression, potentially increasing their vulnerability to surface fisheries. Greater intensity of longline fishing effort occurred above the OMZ compared to adjacent waters. Higher shark catches were associated with strong DO gradients, suggesting potential aggregation along suitable DO gradients contributed to habitat compression and higher fishing-induced mortality. Fisheries controls to counteract deoxygenation effects on shark catches will be needed as oceans continue warming.
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Affiliation(s)
- Marisa Vedor
- CIBIO/InBIO, Universidade do Porto, Campus Agrário de Vairão, Vairão, Portugal.,MARE, Laboratório Marítimo da Guia, Faculdade de Ciências da Universidade de Lisboa, Av. Nossa Senhora do Cabo, Cascais, Portugal
| | - Nuno Queiroz
- CIBIO/InBIO, Universidade do Porto, Campus Agrário de Vairão, Vairão, Portugal.,Marine Biological Association of the United Kingdom, The Laboratory, Citadel Hill, Plymouth, United Kingdom
| | - Gonzalo Mucientes
- CIBIO/InBIO, Universidade do Porto, Campus Agrário de Vairão, Vairão, Portugal.,Instituto de Investigaciones Marinas, Consejo Superior de Investigaciones Científicas (IIM-CSIC), Vigo, Spain
| | - Ana Couto
- CIBIO/InBIO, Universidade do Porto, Campus Agrário de Vairão, Vairão, Portugal
| | - Ivo da Costa
- CIBIO/InBIO, Universidade do Porto, Campus Agrário de Vairão, Vairão, Portugal
| | - António Dos Santos
- CIBIO/InBIO, Universidade do Porto, Campus Agrário de Vairão, Vairão, Portugal
| | - Frederic Vandeperre
- IMAR - Institute of Marine Research, Departamento de Oceanografia e Pescas, Universidade dos Açores, Horta, Portugal.,MARE - Marine and Environmental Sciences Centre, Faculdade de Ciências da Universidade de Lisboa, Lisbon, Portugal.,Okeanos - Departamento de Oceanografia e Pescas, Universidade dos Açores, Horta, Portugal
| | - Jorge Fontes
- IMAR - Institute of Marine Research, Departamento de Oceanografia e Pescas, Universidade dos Açores, Horta, Portugal.,Okeanos - Departamento de Oceanografia e Pescas, Universidade dos Açores, Horta, Portugal
| | - Pedro Afonso
- IMAR - Institute of Marine Research, Departamento de Oceanografia e Pescas, Universidade dos Açores, Horta, Portugal.,Okeanos - Departamento de Oceanografia e Pescas, Universidade dos Açores, Horta, Portugal
| | - Rui Rosa
- MARE, Laboratório Marítimo da Guia, Faculdade de Ciências da Universidade de Lisboa, Av. Nossa Senhora do Cabo, Cascais, Portugal
| | - Nicolas E Humphries
- Marine Biological Association of the United Kingdom, The Laboratory, Citadel Hill, Plymouth, United Kingdom
| | - David W Sims
- Marine Biological Association of the United Kingdom, The Laboratory, Citadel Hill, Plymouth, United Kingdom.,Centre for Biological Sciences, Highfield Campus, University of Southampton, Southampton, United Kingdom.,Ocean and Earth Science, National Oceanography Centre Southampton, Waterfront Campus, University of Southampton, Southampton, United Kingdom
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44
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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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45
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Steckbauer A, Klein SG, Duarte CM. Additive impacts of deoxygenation and acidification threaten marine biota. GLOBAL CHANGE BIOLOGY 2020; 26:5602-5612. [PMID: 32583519 DOI: 10.1111/gcb.15252] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Revised: 06/04/2020] [Accepted: 06/06/2020] [Indexed: 05/27/2023]
Abstract
Deoxygenation in coastal and open-ocean ecosystems rarely exists in isolation but occurs concomitantly with acidification. Here, we first combine meta-data of experimental assessments from across the globe to investigate the potential interactive impacts of deoxygenation and acidification on a broad range of marine taxa. We then characterize the differing degrees of deoxygenation and acidification tested in our dataset using a ratio between the partial pressure of oxygen and carbon dioxide (pO2 /pCO2 ) to assess how biological processes change under an extensive, yet diverse range of pO2 and pCO2 conditions. The dataset comprised 375 experimental comparisons and revealed predominantly additive but variable effects (91.7%, additive; 6.0%, synergistic; and 2.3%, antagonistic) of the dual stressors, yielding negative impacts across almost all responses examined. Our data indicate that the pO2 /pCO2 -ratio offers a simplified metric to characterize the extremity of the concurrent stressors and shows that more severe impacts occurred when ratios represented more extreme deoxygenation and acidification conditions. Importantly, our analysis highlights the need to assess the concurrent impacts of deoxygenation and acidification on marine taxa and that assessments considering the impact of O2 depletion alone will likely underestimate the impacts of deoxygenation events and their ecosystem-wide consequences.
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Affiliation(s)
- Alexandra Steckbauer
- Red Sea Research Center (RSRC) and Computational Bioscience Research Center (CBRC), King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
| | - Shannon G Klein
- Red Sea Research Center (RSRC) and Computational Bioscience Research Center (CBRC), King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
| | - Carlos M Duarte
- Red Sea Research Center (RSRC) and Computational Bioscience Research Center (CBRC), King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
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46
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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.
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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
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47
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Little AG, Loughland I, Seebacher F. What do warming waters mean for fish physiology and fisheries? JOURNAL OF FISH BIOLOGY 2020; 97:328-340. [PMID: 32441327 DOI: 10.1111/jfb.14402] [Citation(s) in RCA: 59] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Revised: 04/30/2020] [Accepted: 05/20/2020] [Indexed: 06/11/2023]
Abstract
Environmental signals act primarily on physiological systems, which then influence higher-level functions such as movement patterns and population dynamics. Increases in average temperature and temperature variability associated with global climate change are likely to have strong effects on fish physiology and thereby on populations and fisheries. Here we review the principal mechanisms that transduce temperature signals and the physiological responses to those signals in fish. Temperature has a direct, thermodynamic effect on biochemical reaction rates. Nonetheless, plastic responses to longer-term thermal signals mean that fishes can modulate their acute thermal responses to compensate at least partially for thermodynamic effects. Energetics are particularly relevant for growth and movement, and therefore for fisheries, and temperature can have pronounced effects on energy metabolism. All energy (ATP) production is ultimately linked to mitochondria, and temperature has pronounced effects on mitochondrial efficiency and maximal capacities. Mitochondria are dependent on oxygen as the ultimate electron acceptor so that cardiovascular function and oxygen delivery link environmental inputs with energy metabolism. Growth efficiency, that is the conversion of food into tissue, changes with temperature, and there are indications that warmer water leads to decreased conversion efficiencies. Moreover, movement and migration of fish relies on muscle function, which is partially dependent on ATP production but also on intracellular calcium cycling within the myocyte. Neuroendocrine processes link environmental signals to regulated responses at the level of different tissues, including muscle. These physiological processes within individuals can scale up to population responses to climate change. A mechanistic understanding of thermal responses is essential to predict the vulnerability of species and populations to climate change.
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Affiliation(s)
| | - Isabella Loughland
- School of Life and Environmental Sciences A08, University of Sydney, Sydney, Australia
| | - Frank Seebacher
- School of Life and Environmental Sciences A08, University of Sydney, Sydney, Australia
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48
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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:jeb.228098. [PMID: 32587069 DOI: 10.1101/2020.05.01.072587] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [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: 05/21/2023]
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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49
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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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50
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Comparative Transcriptome Analysis of Gill Tissue in Response to Hypoxia in Silver Sillago ( Sillago sihama). Animals (Basel) 2020; 10:ani10040628. [PMID: 32268576 PMCID: PMC7222756 DOI: 10.3390/ani10040628] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Revised: 04/05/2020] [Accepted: 04/05/2020] [Indexed: 12/11/2022] Open
Abstract
Silver sillago (Sillago sihama) is a commercially important marine fish species in East Asia. In this study, we compared the transcriptome response to hypoxia stress in the gill tissue of S. sihama. The fish were divided into four groups, such as 1 h of hypoxia (hypoxia1h, DO = 1.5 ± 0.1 mg/L), 4 h of hypoxia (hypoxia4h, DO = 1.5 ± 0.1 mg/L), 4 h of reoxygen (reoxygen4h, DO = 8.0 ± 0.2 mg/L) after 4 h of hypoxia (DO = 1.5 mg/L), and normoxia or control (DO = 8.0 ± 0.2 mg/L) groups. Compared to the normoxia group, a total of 3550 genes were identified as differentially expressed genes (DEGs) (log2foldchange > 1 and padj < 0.05), including 1103, 1451 and 996 genes in hypoxia1h, hypoxia4h and reoxygen4h groups, respectively. Only 247 DEGs were differentially co-expressed in all treatment groups. According to Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis, DEGs were significantly enriched in steroid biosynthesis, biosynthesis of amino acids, glutathione metabolism and metabolism of xenobiotics by cytochrome P450, ferroptosis and drug metabolism-cytochrome P450 pathways. Of these, the cytochrome P450 (CYP) and glutathione S-transferase (GST) gene families were widely expressed. Our study represents the insights into the underlying molecular mechanisms of hypoxia stress.
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