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Pasparakis C, Lohroff T, Biefel F, Cocherell DE, Carson EW, Hung TC, Connon RE, Fangue NA, Todgham AE. Effects of turbidity, temperature and predation cue on the stress response of juvenile delta smelt. Conserv Physiol 2023; 11:coad036. [PMID: 37383481 PMCID: PMC10295165 DOI: 10.1093/conphys/coad036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Revised: 04/21/2023] [Accepted: 06/21/2023] [Indexed: 06/30/2023]
Abstract
The San Francisco Estuary (SFE) is one of the most degraded ecosystems in the United States, and organisms that inhabit it are exposed to a suite of environmental stressors. The delta smelt (Hypomesus transpacificus), a small semi-anadromous fish endemic to the SFE and considered an indicator species, is close to extinction in the wild. The goal of this study was to investigate how environmental alterations to the SFE, such as reductions in turbidities, higher temperatures and increased prevalence of invasive predators affect the physiology and stress response of juvenile delta smelt. Juvenile delta smelt were exposed to two temperatures (17 and 21°C) and two turbidities (1-2 and 10-11 NTU) for 2 weeks. After the first week of exposure, delta smelt were exposed to a largemouth bass (Micropterus salmoides) predator cue at the same time every day for 7 days. Fish were measured and sampled on the first (acute) and final (chronic) day of exposures to predator cues and later analyzed for whole-body cortisol, glucose, lactate, and protein. Length and mass measurements were used to calculate condition factor of fish in each treatment. Turbidity had the greatest effect on juvenile delta smelt and resulted in reduced cortisol, increased glucose and lactate, and greater condition factor. Elevated temperatures reduced available energy in delta smelt, indicated by lower glucose and total protein, whereas predator cue exposure had negligible effects on their stress response. This is the first study to show reduced cortisol in juvenile delta smelt held in turbid conditions and adds to the growing data that suggest this species performs best in moderate temperatures and turbidities. Multistressor experiments are necessary to understand the capacity of delta smelt to respond to the multivariate and dynamic changes in their natural environment, and results from this study should be considered for management-based conservation efforts.
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Affiliation(s)
- Christina Pasparakis
- Department of Environmental Toxicology, University of California Davis, 1 Shields Ave., Davis, CA, USA
- Bodega Marine Laboratory, University of California Davis, 2099 Westshore Rd., Bodega Bay, CA, USA
| | - Toni Lohroff
- Department of Wildlife, Fish and Conservation Biology, University of California Davis, 1 Shields Ave., Davis, CA, USA
- Department of Animal Science, University of California Davis, 1 Shields Ave., Davis, CA, USA
| | - Felix Biefel
- School of Veterinary Medicine, Department of Anatomy, Physiology and Cell Biology, University of California Davis, 1 Shields Ave., Davis, CA, USA
| | - Dennis E Cocherell
- Department of Wildlife, Fish and Conservation Biology, University of California Davis, 1 Shields Ave., Davis, CA, USA
| | - Evan W Carson
- San Francisco Bay-Delta Fish and Wildlife Office, U.S. Fish and Wildlife Service, 650 Capitol Mall, Sacramento, CA, USA
| | - Tien-Chieh Hung
- Fish Conservation and Culture Laboratory, Department of Biological and Agricultural Engineering, University of California Davis, 1 Shields Ave., Davis, CA, USA
| | - Richard E Connon
- School of Veterinary Medicine, Department of Anatomy, Physiology and Cell Biology, University of California Davis, 1 Shields Ave., Davis, CA, USA
| | - Nann A Fangue
- Department of Wildlife, Fish and Conservation Biology, University of California Davis, 1 Shields Ave., Davis, CA, USA
| | - Anne E Todgham
- Department of Animal Science, University of California Davis, 1 Shields Ave., Davis, CA, USA
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Pasparakis C, Wampler AN, Lohroff T, DeCastro F, Cocherell DE, Carson EW, Hung TC, Connon RE, Fangue NA, Todgham AE. Characterizing the stress response in juvenile Delta smelt exposed to multiple stressors. Comp Biochem Physiol A Mol Integr Physiol 2022; 274:111303. [DOI: 10.1016/j.cbpa.2022.111303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Revised: 08/16/2022] [Accepted: 08/24/2022] [Indexed: 10/15/2022]
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3
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Nancollas SJ, Todgham AE. The influence of stochastic temperature fluctuations in shaping the physiological performance of the California mussel, Mytilus californianus. J Exp Biol 2022; 225:276100. [PMID: 35749162 DOI: 10.1242/jeb.243729] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Accepted: 06/20/2022] [Indexed: 11/20/2022]
Abstract
Climate change is forecasted to increase temperature variability and stochasticity. Most of our understanding of thermal physiology of intertidal organisms has come from laboratory experiments that acclimate organisms to submerged conditions and steady-state increases in temperatures. For organisms experiencing the ebb and flow of tides with unpredictable low tide aerial temperatures, the reliability of reported tolerances and thus predicted responses to climate change requires incorporation of environmental complexity into empirical studies. Using the mussel Mytilus californianus, our study examined how stochasticity of the thermal regime influences physiological performance. Mussels were acclimated to either submerged conditions or a tidal cycle that included either predictable, unpredictable or no thermal stress during daytime low tide. Physiological performance was measured through anaerobic metabolism, energy stores and cellular stress mechanisms just before low tide, and cardiac responses during a thermal ramp. Both air exposure and stochasticity of temperature change were important in determining thermal performance. Glycogen content was highest in the mussels from the unpredictable treatment, but there was no difference in the expression of heat shock proteins between thermal treatments, suggesting that mussels prioritise energy reserves to deal with unpredictable low tide conditions. Mussels exposed to fluctuating thermal regimes had lower gill anaerobic metabolism, which could reflect increased metabolic capacity. Our results suggest that while thermal magnitude plays an important role in shaping physiological performance, other key elements of the intertidal environment complexity such as stochasticity, thermal variability, and thermal history are also important considerations for determining how species will respond to climate warming.
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Affiliation(s)
- Sarah J Nancollas
- Department of Animal Science, University of California Davis, Davis, CA USA
| | - Anne E Todgham
- Department of Animal Science, University of California Davis, Davis, CA USA
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4
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Mauduit F, Segarra A, Mandic M, Todgham AE, Baerwald MR, Schreier AD, Fangue NA, Connon RE. Understanding risks and consequences of pathogen infections on the physiological performance of outmigrating Chinook salmon. Conserv Physiol 2022; 10:coab102. [PMID: 35492407 PMCID: PMC9040276 DOI: 10.1093/conphys/coab102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Revised: 10/20/2021] [Accepted: 12/21/2021] [Indexed: 06/14/2023]
Abstract
The greatest concentration of at-risk anadromous salmonids is found in California (USA)-the populations that have been negatively impacted by the degradation of freshwater ecosystems. While climate-driven environmental changes threaten salmonids directly, they also change the life cycle dynamics and geographic distribution of pathogens, their resulting host-pathogen interactions and potential for disease progression. Recent studies have established the correlation between pathogen detection and salmonid smolt mortality during their migration to the ocean. The objective of the present study was to screen for up to 47 pathogens in juvenile Chinook salmon (Oncorhynchus tshawytscha) that were held in cages at two key sites of the Sacramento River (CA, USA) and measure potential consequences on fish health. To do so, we used a combination of transcriptomic analysis, enzymatic assays for energy metabolism and hypoxia and thermal tolerance measures. Results revealed that fish were infected by two myxozoan parasites: Ceratonova shasta and Parvicapsula minibicornis within a 2-week deployment. Compared to the control fish maintained in our rearing facility, infected fish displayed reduced body mass, depleted hepatic glycogen stores and differential regulation of genes involved in the immune and general stress responses. This suggests that infected fish would have lower chances of migration success. In contrast, hypoxia and upper thermal tolerances were not affected by infection, suggesting that infection did not impair their capacity to cope with acute abiotic stressors tested in this study. An evaluation of long-term consequences of the observed reduced body mass and hepatic glycogen depletion is needed to establish a causal relationship between salmon parasitic infection and their migration success. This study highlights that to assess the potential sublethal effects of a stressor, or to determine a suitable management action for fish, studies need to consider a combination of endpoints from the molecular to the organismal level.
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Affiliation(s)
- F Mauduit
- Corresponding author: Department of Anatomy, Physiology & Cell Biology, University of California Davis, 95616 Davis, CA, USA.
| | - A Segarra
- Department of Anatomy, Physiology & Cell Biology, University of California Davis, 95616 Davis, CA, USA
| | - M Mandic
- Department of Animal Science, University of California Davis, 95616 Davis, CA, USA
| | - A E Todgham
- Department of Animal Science, University of California Davis, 95616 Davis, CA, USA
| | - M R Baerwald
- California Department of Water Resources, Division of Environmental Services, 95814 Sacramento, CA, USA
| | - A D Schreier
- Department of Animal Science, University of California Davis, 95616 Davis, CA, USA
| | - N A Fangue
- Department of Wildlife, Fish, and Conservation Biology, University of California Davis, 95616 Davis, CA, USA
| | - R E Connon
- Department of Anatomy, Physiology & Cell Biology, University of California Davis, 95616 Davis, CA, USA
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Naslund AW, Davis BE, Hobbs JA, Fangue NA, Todgham AE. Warming, not CO2-acidified seawater, alters otolith development of juvenile Antarctic emerald rockcod (Trematomus bernacchii). Polar Biol 2021. [DOI: 10.1007/s00300-021-02923-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
AbstractThe combustion of fossil fuels is currently causing rapid rates of ocean warming and acidification worldwide. Projected changes in these parameters have been repeatedly observed to stress the physiological limits and plasticity of many marine species from the molecular to organismal levels. High latitude oceans are among the fastest changing ecosystems; therefore, polar species are projected to be some of the most vulnerable to climate change. Antarctic species are particularly sensitive to environmental change, having evolved for millions of years under stable ocean conditions. Otoliths, calcified structures found in a fish’s inner ear used to sense movement and direction, have been shown to be affected by both warming and CO2-acidified seawater in temperate and tropical fishes but there is no work to date on Antarctic fishes. In this study, juvenile emerald rockcod (Trematomus bernacchii) were exposed to projected seawater warming and CO2-acidification for the year 2100 over 28 days. Sagittal otoliths were analyzed for changes in area, perimeter, length, width and shape. We found ocean warming increased the growth rate of otoliths, while CO2-acidified seawater and the interaction of warming and acidification did not have an effect on otolith development. Elevated temperature also altered the shape of otoliths. If otolith development is altered under future warming scenarios, sensory functions such as hearing, orientation, and movement may potentially be impaired. Changes in these basic somatic abilities could have broad implications for the general capabilities and ecology of early life stages of Antarctic fishes.
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Del Rio AM, Mukai GN, Martin BT, Johnson RC, Fangue NA, Israel JA, Todgham AE. Differential sensitivity to warming and hypoxia during development and long-term effects of developmental exposure in early life stage Chinook salmon. Conserv Physiol 2021; 9:coab054. [PMID: 34257996 PMCID: PMC8271147 DOI: 10.1093/conphys/coab054] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 04/28/2021] [Accepted: 06/15/2021] [Indexed: 05/13/2023]
Abstract
Warming and hypoxia are two stressors commonly found within natural salmon redds that are likely to co-occur. Warming and hypoxia can interact physiologically, but their combined effects during fish development remain poorly studied, particularly stage-specific effects and potential carry-over effects. To test the impacts of warm water temperature and hypoxia as individual and combined developmental stressors, late fall-run Chinook salmon embryos were reared in 10 treatments from fertilization through hatching with two temperatures [10°C (ambient) and 14°C (warm)], two dissolved oxygen saturation levels [normoxia (100% air saturation, 10.4-11.4 mg O2/l) and hypoxia (50% saturation, 5.5 mg O2/l)] and three exposure times (early [eyed stage], late [silver-eyed stage] and chronic [fertilization through hatching]). After hatching, all treatments were transferred to control conditions (10°C and 100% air saturation) through the fry stage. To study stage-specific effects of stressor exposure we measured routine metabolic rate (RMR) at two embryonic stages, hatching success and growth. To evaluate carry-over effects, where conditions during one life stage influence performance in a later stage, RMR of all treatments was measured in control conditions at two post-hatch stages and acute stress tolerance was measured at the fry stage. We found evidence of stage-specific effects of both stressors during exposure and carry-over effects on physiological performance. Both individual stressors affected RMR, growth and developmental rate while multiple stressors late in development reduced hatching success. RMR post-hatch showed persistent effects of embryonic stressor exposure that may underlie differences observed in developmental timing and acute stress tolerance. The responses to stressors that varied by stage during development suggest that stage-specific management efforts could support salmon embryo survival. The persistent carry-over effects also indicate that considering sub-lethal effects of developmental stressor exposure may be important to understanding how climate change influences the performance of salmon across life stages.
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Affiliation(s)
- Annelise M Del Rio
- Department of Animal Science, University of California Davis, Davis, CA 95616, USA
| | - Gabriella N Mukai
- Department of Animal Science, University of California Davis, Davis, CA 95616, USA
- Department of Biology, University of Hawai’i at Mānoa, Honolulu, HI 96822, USA
| | - Benjamin T Martin
- University of California Santa Cruz, Cooperative Institute for Marine Ecosystems and Climate (CIMEC), Santa Cruz, CA 95064, USA
- Southwest Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, 110 Shaffer Road, Santa Cruz, CA 95060, USA
- Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, 1098 XH Amsterdam, the Netherlands
| | - Rachel C Johnson
- Department of Animal Science, University of California Davis, Davis, CA 95616, USA
- University of California Santa Cruz, Cooperative Institute for Marine Ecosystems and Climate (CIMEC), Santa Cruz, CA 95064, USA
- Southwest Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, 110 Shaffer Road, Santa Cruz, CA 95060, USA
| | - Nann A Fangue
- Department of Wildlife, Fish, and Conservation Biology, University of California Davis, Davis, CA 95616, USA
| | - Joshua A Israel
- Bay-Delta Office, U.S. Bureau of Reclamation, Sacramento, CA 95825, USA
| | - Anne E Todgham
- Department of Animal Science, University of California Davis, Davis, CA 95616, USA
- Corresponding author: Department of Animal Science, University of California Davis, Davis, CA 95616, USA.
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7
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Cooke SJ, Bergman JN, Madliger CL, Cramp RL, Beardall J, Burness G, Clark TD, Dantzer B, de la Barrera E, Fangue NA, Franklin CE, Fuller A, Hawkes LA, Hultine KR, Hunt KE, Love OP, MacMillan HA, Mandelman JW, Mark FC, Martin LB, Newman AEM, Nicotra AB, Raby GD, Robinson SA, Ropert-Coudert Y, Rummer JL, Seebacher F, Todgham AE, Tomlinson S, Chown SL. One hundred research questions in conservation physiology for generating actionable evidence to inform conservation policy and practice. Conserv Physiol 2021; 9:coab009. [PMID: 33859825 PMCID: PMC8035967 DOI: 10.1093/conphys/coab009] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Revised: 01/28/2021] [Accepted: 01/29/2021] [Indexed: 05/05/2023]
Abstract
Environmental change and biodiversity loss are but two of the complex challenges facing conservation practitioners and policy makers. Relevant and robust scientific knowledge is critical for providing decision-makers with the actionable evidence needed to inform conservation decisions. In the Anthropocene, science that leads to meaningful improvements in biodiversity conservation, restoration and management is desperately needed. Conservation Physiology has emerged as a discipline that is well-positioned to identify the mechanisms underpinning population declines, predict responses to environmental change and test different in situ and ex situ conservation interventions for diverse taxa and ecosystems. Here we present a consensus list of 10 priority research themes. Within each theme we identify specific research questions (100 in total), answers to which will address conservation problems and should improve the management of biological resources. The themes frame a set of research questions related to the following: (i) adaptation and phenotypic plasticity; (ii) human-induced environmental change; (iii) human-wildlife interactions; (iv) invasive species; (v) methods, biomarkers and monitoring; (vi) policy, engagement and communication; (vii) pollution; (viii) restoration actions; (ix) threatened species; and (x) urban systems. The themes and questions will hopefully guide and inspire researchers while also helping to demonstrate to practitioners and policy makers the many ways in which physiology can help to support their decisions.
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Affiliation(s)
- Steven J Cooke
- Fish Ecology and Conservation Physiology Laboratory, Department of Biology and Institute of Environmental and Interdisciplinary Science, Carleton University, 1125 Colonel By Dr., Ottawa, Ontario K1S 5B6, Canada
- Corresponding author: Fish Ecology and Conservation Physiology Laboratory, Department of Biology and Institute of Environmental and Interdisciplinary Science, Carleton University, 1125 Colonel By Dr., Ottawa, Ontario K1S 5B6, Canada.
| | - Jordanna N Bergman
- Fish Ecology and Conservation Physiology Laboratory, Department of Biology and Institute of Environmental and Interdisciplinary Science, Carleton University, 1125 Colonel By Dr., Ottawa, Ontario K1S 5B6, Canada
| | - Christine L Madliger
- Fish Ecology and Conservation Physiology Laboratory, Department of Biology and Institute of Environmental and Interdisciplinary Science, Carleton University, 1125 Colonel By Dr., Ottawa, Ontario K1S 5B6, Canada
| | - Rebecca L Cramp
- School of Biological Sciences, The University of Queensland, Brisbane 4072, Australia
| | - John Beardall
- Securing Antarctica’s Environmental Future, School of Biological Sciences, Monash University, Clayton, Victoria 3800, Australia
| | - Gary Burness
- Department of Biology, Trent University, 1600 West Bank Drive, Peterborough, Ontario K9L 0G2, Canada
| | - Timothy D Clark
- School of Life and Environmental Sciences, Deakin University, Geelong, Victoria 3216, Australia
| | - Ben Dantzer
- Department of Psychology, Department of Ecology & Evolutionary Biology, Ann Arbor, MI 48109, USA
| | - Erick de la Barrera
- Instituto de Investigaciones en Ecosistemas y Sustentabilidad, Universidad Nacional Autónoma de México, Antigua Carretera a Pátzcuaro 8701, Morelia, Michoacán, 58190, Mexico
| | - Nann A Fangue
- Department of Wildlife, Fish & Conservation Biology, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA
| | - Craig E Franklin
- School of Biological Sciences, The University of Queensland, Brisbane 4072, Australia
| | - Andrea Fuller
- Brain Function Research Group, School of Physiology, University of the Witwatersrand, 7 York Rd, Parktown, 2193, South Africa
| | - Lucy A Hawkes
- College of Life and Environmental Sciences, Hatherly Laboratories, University of Exeter, Prince of Wales Road, Exeter EX4 4PS, UK
| | - Kevin R Hultine
- Department of Research, Conservation and Collections, Desert Botanical Garden, Phoenix, AZ 85008, USA
| | - Kathleen E Hunt
- Smithsonian-Mason School of Conservation, 1500 Remount Road, Front Royal, VA 22630, USA
| | - Oliver P Love
- Department of Integrative Biology, University of Windsor, 401 Sunset Avenue, Windsor, Ontario N9B 3P4, Canada
| | - Heath A MacMillan
- Department of Biology and Institute of Biochemistry, Carleton University, 1125 Colonel By Dr., Ottawa, Ontario K1S 5B6, Canada
| | - John W Mandelman
- Anderson Cabot Center for Ocean Life, New England Aquarium, 1 Central Wharf, Boston, MA, 02110, USA
| | - Felix C Mark
- Department of Integrative Ecophysiology, Alfred Wegener Institute Helmholtz Center for Polar and Marine Research, Am Handelshafen 12, 27570 Bremerhaven, Germany
| | - Lynn B Martin
- Global Health and Infectious Disease Research, University of South Florida, 3720 Spectrum Boulevard, Tampa, FL 33612, USA
| | - Amy E M Newman
- Department of Integrative Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - Adrienne B Nicotra
- Research School of Biology, Australian National University, Canberra, Australian Capital Territory 2601, Australia
| | - Graham D Raby
- Department of Biology, Trent University, 1600 West Bank Drive, Peterborough, Ontario K9L 0G2, Canada
| | - Sharon A Robinson
- School of Earth, Atmospheric and Life Sciences (SEALS) and Centre for Sustainable Ecosystem Solutions, University of Wollongong, Wollongong, New South Wales 2522, Australia
| | - Yan Ropert-Coudert
- Centre d'Etudes Biologiques de Chizé, CNRS UMR 7372—La Rochelle Université, 79360 Villiers-en-Bois, France
| | - Jodie L Rummer
- ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, Queensland 4811, Australia
| | - Frank Seebacher
- School of Life and Environmental Sciences A08, University of Sydney, New South Wales 2006, Australia
| | - Anne E Todgham
- Department of Animal Science, University of California Davis, Davis, CA 95616, USA
| | - Sean Tomlinson
- School of Biological Sciences, University of Adelaide, North Terrace, Adelaide, South Australia 5000, Australia
| | - Steven L Chown
- Securing Antarctica’s Environmental Future, School of Biological Sciences, Monash University, Clayton, Victoria 3800, Australia
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Abstract
Antarctic fishes have evolved under stable, extreme cold temperatures for millions of years. Adapted to thrive in the cold environment, their specialized phenotypes will likely render them particularly susceptible to future ocean warming and acidification as a result of climate change. Moving from a period of stability to one of environmental change, species persistence will depend on maintaining energetic equilibrium, or sustaining the increased energy demand without compromising important biological functions such as growth and reproduction. Metabolic capacity to acclimate, marked by a return to metabolic equilibrium through physiological compensation of routine metabolic rate (RMR), will likely determine which species will be better poised to cope with shifts in environmental conditions. Focusing on the suborder Notothenioidei, a dominant group of Antarctic fishes, and in particular four well-studied species, Trematomus bernacchii, Pagothenia borchgrevinki, Notothenia rossii, and N. coriiceps, we discuss metabolic acclimation potential to warming and CO2-acidification using an integrative and comparative framework. There are species-specific differences in the physiological compensation of RMR during warming and the duration of acclimation time required to achieve compensation; for some species, RMR fully recovered within 3.5 weeks of exposure, such as P. borchgrevinki, while for other species, such as N. coriiceps, RMR remained significantly elevated past 9 weeks of exposure. In all instances, added exposure to increased PCO2, further compromised the ability of species to return RMR to pre-exposure levels. The period of metabolic imbalance, marked by elevated RMR, was underlined by energetic disturbance and elevated energetic costs, which shifted energy away from fitness-related functions, such as growth. In T. bernacchii and N. coriiceps, long duration of elevated RMR impacted condition factor and/or growth rate. Low growth rate can affect development and ultimately the timing of reproduction, severely compromising the species' survival potential and the biodiversity of the notothenioid lineage. Therefore, the ability to achieve full compensation of RMR, and in a short-time frame, in order to avoid long term consequences of metabolic imbalance, will likely be an important determinant in a species' capacity to persist in a changing environment. Much work is still required to develop our understanding of the bioenergetics of Antarctic fishes in the face of environmental change, and a targeted approach of nesting a mechanistic focus in an ecological and comparative framework will better aid our predictions on the effect of global climate change on species persistence in the polar regions.
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Affiliation(s)
- Anne E Todgham
- Department of Animal Science, University of California Davis, Davis, CA 95616, USA
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Frazier AJ, Jensen NR, Young SP, Todgham AE. Does a cannibal feeding strategy impart differential metabolic performance in young burbot ( Lota lota maculosa)? Conserv Physiol 2020; 8:coaa034. [PMID: 32391152 PMCID: PMC7196671 DOI: 10.1093/conphys/coaa034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Revised: 03/05/2020] [Accepted: 03/31/2020] [Indexed: 06/11/2023]
Abstract
The practice of mitigating cannibalism in aquaculture is an important focus for hatcheries seeking to maximize yield and has been maintained in hatcheries focusing on wild stock restoration. We hypothesize, however, that a cannibal feeding strategy may confer performance advantages over a non-cannibal feeding strategy and that perhaps cannibal size grading may not be optimal for hatcheries focusing on conservation goals. This study examined metabolic performance differences between cannibal and non-cannibal burbot, Lota lota maculosa, at the Kootenai Tribe of Idaho Twin Rivers Hatchery in Moyie Springs, ID, USA. After habitat alteration led to functional extinction of burbot in the region, the Twin Rivers Hatchery has played a leading role in the reestablishment of burbot in the Kootenai River, ID, and British Columbia. We examined morphometric data (weight, length and condition factor), whole animal resting metabolic rate and the enzyme activity of lactate dehydrogenase, citrate synthase and 3-hydroxyacyl-CoA dehydrogenase to describe the baseline metabolic performance of cannibal and non-cannibal burbot. Taken together, our results demonstrated significant differences in the metabolic strategies of cannibal vs. non-cannibal burbot, where cannibals relied more heavily on carbohydrate metabolism and non-cannibals relied more heavily on glycolytic and lipid metabolism. This study demonstrates the need to reevaluate the traditional practice of removing cannibal fish in conservation hatcheries, as it may not be the ideal strategy of raising the most robust individuals for release. When natural habitat conditions cannot be restored due to permanent habitat alteration, prioritizing release of higher performing individuals could help achieve conservation goals.
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Affiliation(s)
- Amanda J Frazier
- Department of Animal Science, University of California Davis, Davis, CA 95616, USA
| | | | - Shawn P Young
- Kootenai Tribe of Idaho, Bonners Ferry, ID 83805, USA
| | - Anne E Todgham
- Department of Animal Science, University of California Davis, Davis, CA 95616, USA
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10
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Cooke SJ, Madliger CL, Cramp RL, Beardall J, Burness G, Chown SL, Clark TD, Dantzer B, de la Barrera E, Fangue NA, Franklin CE, Fuller A, Hawkes LA, Hultine KR, Hunt KE, Love OP, MacMillan HA, Mandelman JW, Mark FC, Martin LB, Newman AEM, Nicotra AB, Robinson SA, Ropert-Coudert Y, Rummer JL, Seebacher F, Todgham AE. Reframing conservation physiology to be more inclusive, integrative, relevant and forward-looking: reflections and a horizon scan. Conserv Physiol 2020; 8:coaa016. [PMID: 32274063 PMCID: PMC7125050 DOI: 10.1093/conphys/coaa016] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/26/2019] [Revised: 01/27/2020] [Accepted: 02/10/2020] [Indexed: 05/21/2023]
Abstract
Applying physiological tools, knowledge and concepts to understand conservation problems (i.e. conservation physiology) has become commonplace and confers an ability to understand mechanistic processes, develop predictive models and identify cause-and-effect relationships. Conservation physiology is making contributions to conservation solutions; the number of 'success stories' is growing, but there remain unexplored opportunities for which conservation physiology shows immense promise and has the potential to contribute to major advances in protecting and restoring biodiversity. Here, we consider how conservation physiology has evolved with a focus on reframing the discipline to be more inclusive and integrative. Using a 'horizon scan', we further explore ways in which conservation physiology can be more relevant to pressing conservation issues of today (e.g. addressing the Sustainable Development Goals; delivering science to support the UN Decade on Ecosystem Restoration), as well as more forward-looking to inform emerging issues and policies for tomorrow. Our horizon scan provides evidence that, as the discipline of conservation physiology continues to mature, it provides a wealth of opportunities to promote integration, inclusivity and forward-thinking goals that contribute to achieving conservation gains. To advance environmental management and ecosystem restoration, we need to ensure that the underlying science (such as that generated by conservation physiology) is relevant with accompanying messaging that is straightforward and accessible to end users.
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Affiliation(s)
- Steven J Cooke
- Fish Ecology and Conservation Physiology Laboratory, Department of Biology and Institute of Environmental and Interdisciplinary Science, Carleton University, 1125 Colonel By Dr., Ottawa, ON, K1S 5B6, Canada
- Corresponding author: Fish Ecology and Conservation Physiology Laboratory, Department of Biology and Institute of Environmental and Interdisciplinary Science, Carleton University, 1125 Colonel By Dr., Ottawa, ON, K1S 5B6, Canada.
| | - Christine L Madliger
- Fish Ecology and Conservation Physiology Laboratory, Department of Biology and Institute of Environmental and Interdisciplinary Science, Carleton University, 1125 Colonel By Dr., Ottawa, ON, K1S 5B6, Canada
| | - Rebecca L Cramp
- School of Biological Sciences, The University of Queensland, Brisbane, 4072, Australia
| | - John Beardall
- School of Biological Sciences, Monash University, Clayton, Victoria 3800, Australia
| | - Gary Burness
- Department of Biology, Trent University, 1600 West Bank Drive, Peterborough, ON, K9L 0G2, Canada
| | - Steven L Chown
- School of Biological Sciences, Monash University, Clayton, Victoria 3800, Australia
| | - Timothy D Clark
- School of Life and Environmental Sciences, Deakin University, Geelong, Victoria 14 3216, Australia
| | - Ben Dantzer
- Department of Psychology, Department of Ecology & Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Erick de la Barrera
- Instituto de Investigaciones en Ecosistemas y Sustentabilidad, Universidad Nacional Autónoma de México, Antigua Carretera a Pátzcuaro 8701, Morelia, Michoacán, 58190, Mexico
| | - Nann A Fangue
- Department of Wildlife, Fish & Conservation Biology, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA
| | - Craig E Franklin
- School of Biological Sciences, The University of Queensland, Brisbane, 4072, Australia
| | - Andrea Fuller
- Brain Function Research Group, School of Physiology, University of the Witwatersrand, 7 York Rd, Parktown, 2193, South Africa
| | - Lucy A Hawkes
- College of Life and Environmental Sciences, Hatherly Laboratories, University of Exeter, Prince of Wales Road, Exeter, EX4 4PS, UK
| | - Kevin R Hultine
- Department of Research, Conservation and Collections, Desert Botanical Garden, Phoenix, AZ 85008, USA
| | - Kathleen E Hunt
- Department of Biology, George Mason University, Fairfax, VA 22030, USA
| | - Oliver P Love
- Department of Integrative Biology, University of Windsor, 401 Sunset Avenue, Windsor, ON N9B 3P4, Canada
| | - Heath A MacMillan
- Department of Biology and Institute of Biochemistry, Carleton University, 1125 Colonel By Dr., Ottawa, ON K1S 5B6, Canada
| | - John W Mandelman
- Anderson Cabot Center for Ocean Life, New England Aquarium, 1 Central Wharf, Boston, MA 02110, USA
| | - Felix C Mark
- Department of Integrative Ecophysiology, Alfred Wegener Institute Helmholtz Center for Polar and Marine Research, Am Handelshafen 12, 27574 Bremerhaven, Germany
| | - Lynn B Martin
- Global Health and Infectious Disease Research, University of South Florida, 3720 Spectrum Boulevard, Tampa, FL 33612, USA
| | - Amy E M Newman
- Department of Integrative Biology, University of Guelph, Guelph, ON, N1G 2W1, Canada
| | - Adrienne B Nicotra
- Research School of Biology, Australian National University, Canberra, ACT 2601, Australia
| | - Sharon A Robinson
- School of Earth, Atmospheric and Life Sciences (SEALS) and Centre for Sustainable Ecosystem Solutions, University of Wollongong, Wollongong, NSW 2522, Australia
| | - Yan Ropert-Coudert
- Centre d'Etudes Biologiques de Chizé, CNRS UMR 7372 - La Rochelle Université, 79360 Villiers-en-Bois, France
| | - Jodie L Rummer
- ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, QLD 5811, Australia
| | - Frank Seebacher
- School of Life and Environmental Sciences A08, University of Sydney, NSW 2006, Australia
| | - Anne E Todgham
- Department of Animal Science, University of California Davis, One Shields Ave. Davis, CA, 95616, USA
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11
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Rodgers EM, Poletto JB, Gomez Isaza DF, Van Eenennaam JP, Connon RE, Todgham AE, Seesholtz A, Heublein JC, Cech JJ, Kelly JT, Fangue NA. Integrating physiological data with the conservation and management of fishes: a meta-analytical review using the threatened green sturgeon ( Acipenser medirostris). Conserv Physiol 2019; 7:coz035. [PMID: 31281658 PMCID: PMC6601218 DOI: 10.1093/conphys/coz035] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Revised: 04/26/2019] [Accepted: 05/20/2019] [Indexed: 05/04/2023]
Abstract
Reversing global declines in the abundance and diversity of fishes is dependent on science-based conservation solutions. A wealth of data exist on the ecophysiological constraints of many fishes, but much of this information is underutilized in recovery plans due to a lack of synthesis. Here, we used the imperiled green sturgeon (Acipenser medirostris) as an example of how a quantitative synthesis of physiological data can inform conservation plans, identify knowledge gaps and direct future research actions. We reviewed and extracted metadata from peer-reviewed papers on green sturgeon. A total of 105 publications were identified, spanning multiple disciplines, with the primary focus being conservation physiology (23.8%). A meta-analytical approach was chosen to summarize the mean effects of prominent stressors (elevated temperatures, salinity, low food availability and contaminants) on several physiological traits (growth, thermal tolerance, swimming performance and heat shock protein expression). All examined stressors significantly impaired green sturgeon growth, and additional stressor-specific costs were documented. These findings were then used to suggest several management actions, such as mitigating salt intrusion in nursery habitats and maintaining water temperatures within optimal ranges during peak spawning periods. Key data gaps were also identified; research efforts have been biased towards juvenile (38.1%) and adult (35.2%) life-history stages, and less data are available for early life-history stages (embryonic, 11.4%; yolk-sac larvae, 12.4%; and post yolk-sac larvae, 16.2%). Similarly, most data were collected from single-stressor studies (91.4%) and there is an urgent need to understand interactions among stressors as anthropogenic change is multi-variate and dynamic. Collectively, these findings provide an example of how meta-analytic reviews are a powerful tool to inform management actions, with the end goal of maximizing conservation gains from research efforts.
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Affiliation(s)
- Essie M Rodgers
- Wildlife, Fish and Conservation Biology, University of California Davis, One Shields Ave., Davis, CA, USA
| | - Jamilynn B Poletto
- School of Natural Resources, University of Nebraska-Lincoln, 3310 Holdrege St., Lincoln, NE, USA
| | - Daniel F Gomez Isaza
- School of Biological Sciences, The University Queensland, Brisbane, QLD, Australia
| | - Joel P Van Eenennaam
- Department of Animal Science, University of California Davis, One Shields Ave., Davis, CA, USA
| | - Richard E Connon
- Department of Anatomy, Physiology and Cell Biology, University of California Davis, One Shields Ave., Davis, CA, USA
| | - Anne E Todgham
- Department of Animal Science, University of California Davis, One Shields Ave., Davis, CA, USA
| | - Alicia Seesholtz
- California Department of Water Resources, Industrial Blvd., West Sacramento, CA, USA
| | - Joe C Heublein
- NOAA National Marine Fisheries Program, West Coast Region, Capital Mall, Sacramento, CA, USA
| | - Joseph J Cech
- Wildlife, Fish and Conservation Biology, University of California Davis, One Shields Ave., Davis, CA, USA
| | - John T Kelly
- Fisheries Branch, California Department of Fish and Wildlife, Sacramento, CA, USA
| | - Nann A Fangue
- Wildlife, Fish and Conservation Biology, University of California Davis, One Shields Ave., Davis, CA, USA
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12
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Leal MJ, Van Eenennaam JP, Schreier AD, Todgham AE. Triploidy in white sturgeon (Acipenser transmontanus): Effects of acute stress and warm acclimation on physiological performance. Comp Biochem Physiol A Mol Integr Physiol 2019; 229:10-17. [DOI: 10.1016/j.cbpa.2018.11.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Accepted: 11/08/2018] [Indexed: 01/12/2023]
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13
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Davis BE, Cocherell DE, Sommer T, Baxter RD, Hung TC, Todgham AE, Fangue NA. Sensitivities of an endemic, endangered California smelt and two non-native fishes to serial increases in temperature and salinity: implications for shifting community structure with climate change. Conserv Physiol 2019; 7:coy076. [PMID: 30842886 PMCID: PMC6387996 DOI: 10.1093/conphys/coy076] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/25/2018] [Revised: 11/29/2018] [Accepted: 12/18/2018] [Indexed: 06/09/2023]
Abstract
In many aquatic systems, native fishes are in decline and the factors responsible are often elusive. In the San Francisco Estuary (SFE) in California, interactions among native and non-native species are key factors contributing to the decline in abundance of endemic, endangered Delta Smelt (Hypomesus transpacificus). Climate change and drought-related stressors are further exacerbating declines. To assess how multiple environmental changes affect the physiology of native Delta Smelt and non-native Mississippi Silverside (Menidia beryllina) and Largemouth Bass (Micropterus salmoides), fishes were exposed to serial exposures of a single stressor (elevated temperature or salinity) followed by two stressors (elevated temperature and salinity) to determine how a single stressor affects the capacity to cope with the addition of a second stressor. Critical thermal maximum (CTMax; a measure of upper temperature tolerance) was determined after 0, 2, 4 and 7 days following single and multiple stressors of elevated temperature (16°C vs. 20°C) and salinity (2.4 vs. 8-12 ppt, depending on species). Under control conditions, non-native fishes had significantly higher CTMax than the native Delta Smelt. An initial temperature or salinity stressor did not negatively affect the ability of any species to tolerate a subsequent multiple stressor. While elevated salinity had little effect on CTMax, a 4°C increase in temperature increased CTMax. Bass experienced an additive effect of increased temperature and salinity on CTMax, such that CTMax further increased under multiple stressors. In addition, Bass demonstrated physiological sensitivity to multiple stressors demonstrated by changes in hematocrit and plasma osmolality, whereas the physiology of Silversides remained unaffected. Non-native Bass and Mississippi Silversides showed consistently higher thermal tolerance limits than the native Delta Smelt, supporting their abundance in warmer SFE habitats. Continued increases in SFE water temperatures predicted with climate change may further impact endangered Delta Smelt populations directly if habitat temperatures exceed thermal limits.
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Affiliation(s)
- Brittany E Davis
- Department of Wildlife, Fish and Conservation Biology, University of California Davis, Davis, CA, USA
- Department of Animal Sciences, University of California Davis, Davis, CA, USA
- California Department of Water Resources, Division of Environmental Services, PO Box 942836, Sacramento, CA, USA
| | - Dennis E Cocherell
- Department of Wildlife, Fish and Conservation Biology, University of California Davis, Davis, CA, USA
| | - Ted Sommer
- California Department of Water Resources, Division of Environmental Services, PO Box 942836, Sacramento, CA, USA
| | - Randall D Baxter
- California Department of Fish and Wildlife, Bay-Delta Region 3, 2109 Arch-Airport Rd., Suite 100, Stockton, CA, USA
| | - Tien-Chieh Hung
- Department of Biological and Agricultural Engineering, University of California, Davis, CA, USA
| | - Anne E Todgham
- Department of Animal Sciences, University of California Davis, Davis, CA, USA
| | - Nann A Fangue
- Department of Wildlife, Fish and Conservation Biology, University of California Davis, Davis, CA, USA
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14
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Del Rio AM, Davis BE, Fangue NA, Todgham AE. Combined effects of warming and hypoxia on early life stage Chinook salmon physiology and development. Conserv Physiol 2019; 7:coy078. [PMID: 30834124 PMCID: PMC6387995 DOI: 10.1093/conphys/coy078] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Revised: 11/30/2018] [Accepted: 12/31/2018] [Indexed: 05/21/2023]
Abstract
Early life stages of salmonids are particularly vulnerable to warming and hypoxia, which are common stressors in hyporheic, gravel bed, rearing habitat (i.e. a 'redd'). With the progression of global climate change, high temperatures and hypoxia may co-occur more frequently within redds, particularly for salmonid species at their southern range limit. Warming and hypoxia have competing effects on energy supply and demand, which can be detrimental to energy-limited early life stages. We examined how elevated temperature and hypoxia as individual and combined stressors affected the survival, physiological performance, growth, and development of Chinook salmon (Oncorhynchus tshawytscha). We reared late fall-run Chinook salmon from fertilization to the fry stage in a fully factorial design of two temperatures [10°C (ambient) and 14°C (warm)] and two oxygen levels [normoxia (100% air saturation, 10 mg O2/l) and hypoxia (50% saturation, 5.5 mg O2/l)]. Rearing in hypoxia significantly reduced hatching success, especially in combination with warming. Both warming and hypoxia improved acute thermal tolerance. While rearing in hypoxia improved tolerance to acute hypoxia stress, warming reduced hypoxia tolerance. Hypoxia-reared fish were smaller at hatch, but were able to reach similar sizes to the normoxia-reared fish by the fry stage. High temperature and normoxia resulted in the fastest rate of development while low temperature and hypoxia resulted in the slowest rate of development. Despite improved physiological tolerance to acute heat and hypoxia stress, hypoxia-reared embryos had reduced survival and growth, which could have larger population-level effects. These results suggest that both warming and hypoxia are important factors to address in conservation strategies for Chinook salmon.
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Affiliation(s)
- Annelise M Del Rio
- Department of Animal Science, University of California Davis, Davis, CA, USA
| | - Brittany E Davis
- Department of Animal Science, University of California Davis, Davis, CA, USA
- Department of Wildlife, Fish, and Conservation Biology, University of California Davis, Davis, CA, USA
- California Department of Water Resources, Division of Environmental Services, PO Box 942836, Sacramento, CA, USA
| | - Nann A Fangue
- Department of Wildlife, Fish, and Conservation Biology, University of California Davis, Davis, CA, USA
| | - Anne E Todgham
- Department of Animal Science, University of California Davis, Davis, CA, USA
- Corresponding author: Department of Animal Science, University of California Davis, Davis, CA 95616, USA.
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15
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Leal MJ, Clark BE, Van Eenennaam JP, Schreier AD, Todgham AE. The effects of warm temperature acclimation on constitutive stress, immunity, and metabolism in white sturgeon (Acipenser transmontanus) of different ploidies. Comp Biochem Physiol A Mol Integr Physiol 2018; 224:23-34. [DOI: 10.1016/j.cbpa.2018.05.021] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Revised: 05/22/2018] [Accepted: 05/24/2018] [Indexed: 11/16/2022]
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16
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Rodgers EM, Cocherell DE, Nguyen TX, Todgham AE, Fangue NA. Plastic responses to diel thermal variation in juvenile green sturgeon, Acipenser medirostris. J Therm Biol 2018; 76:147-155. [DOI: 10.1016/j.jtherbio.2018.07.015] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2018] [Revised: 06/16/2018] [Accepted: 07/22/2018] [Indexed: 11/24/2022]
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17
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Davis BE, Flynn EE, Miller NA, Nelson FA, Fangue NA, Todgham AE. Antarctic emerald rockcod have the capacity to compensate for warming when uncoupled from CO 2 -acidification. Glob Chang Biol 2018; 24:e655-e670. [PMID: 29155460 DOI: 10.1111/gcb.13987] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Revised: 10/03/2017] [Accepted: 11/08/2017] [Indexed: 06/07/2023]
Abstract
Increases in atmospheric CO2 levels and associated ocean changes are expected to have dramatic impacts on marine ecosystems. Although the Southern Ocean is experiencing some of the fastest rates of change, few studies have explored how Antarctic fishes may be affected by co-occurring ocean changes, and even fewer have examined early life stages. To date, no studies have characterized potential trade-offs in physiology and behavior in response to projected multiple climate change stressors (ocean acidification and warming) on Antarctic fishes. We exposed juvenile emerald rockcod Trematomus bernacchii to three PCO2 treatments (~450, ~850, and ~1,200 μatm PCO2 ) at two temperatures (-1 or 2°C). After 2, 7, 14, and 28 days, metrics of physiological performance including cardiorespiratory function (heart rate [fH ] and ventilation rate [fV ]), metabolic rate (M˙O2), and cellular enzyme activity were measured. Behavioral responses, including scototaxis, activity, exploration, and escape response were assessed after 7 and 14 days. Elevated PCO2 independently had little impact on either physiology or behavior in juvenile rockcod, whereas warming resulted in significant changes across acclimation time. After 14 days, fH , fV and M˙O2 significantly increased with warming, but not with elevated PCO2 . Increased physiological costs were accompanied by behavioral alterations including increased dark zone preference up to 14%, reduced activity by 12%, as well as reduced escape time suggesting potential trade-offs in energetics. After 28 days, juvenile rockcod demonstrated a degree of temperature compensation as fV , M˙O2, and cellular metabolism significantly decreased following the peak at 14 days; however, temperature compensation was only evident in the absence of elevated PCO2 . Sustained increases in fV and M˙O2 after 28 days exposure to elevated PCO2 indicate additive (fV ) and synergistic (M˙O2) interactions occurred in combination with warming. Stressor-induced energetic trade-offs in physiology and behavior may be an important mechanism leading to vulnerability of Antarctic fishes to future ocean change.
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Affiliation(s)
- Brittany E Davis
- Department of Animal Science, University of California Davis, Davis, CA, USA
- Department of Wildlife, Fish and Conservation Biology, University of California Davis, Davis, CA, USA
| | - Erin E Flynn
- Department of Animal Science, University of California Davis, Davis, CA, USA
| | - Nathan A Miller
- Department of Animal Science, University of California Davis, Davis, CA, USA
- Romberg Tiburon Center, San Francisco State University, Tiburon, CA, USA
| | - Frederick A Nelson
- Department of Animal Science, University of California Davis, Davis, CA, USA
- Department of Biology, Howard University, Washington, DC, USA
| | - Nann A Fangue
- Department of Wildlife, Fish and Conservation Biology, University of California Davis, Davis, CA, USA
| | - Anne E Todgham
- Department of Animal Science, University of California Davis, Davis, CA, USA
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18
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Abstract
There is growing recognition of the need to understand the mechanisms underlying organismal resilience (i.e. tolerance, acclimatization) to environmental change to support the conservation management of sensitive and economically important species. Here, we discuss how functional genomics can be used in conservation biology to provide a cellular-level understanding of organismal responses to environmental conditions. In particular, the integration of transcriptomics with physiological and ecological research is increasingly playing an important role in identifying functional physiological thresholds predictive of compensatory responses and detrimental outcomes, transforming the way we can study issues in conservation biology. Notably, with technological advances in RNA sequencing, transcriptome-wide approaches can now be applied to species where no prior genomic sequence information is available to develop species-specific tools and investigate sublethal impacts that can contribute to population declines over generations and undermine prospects for long-term conservation success. Here, we examine the use of transcriptomics as a means of determining organismal responses to environmental stressors and use key study examples of conservation concern in fishes to highlight the added value of transcriptome-wide data to the identification of functional response pathways. Finally, we discuss the gaps between the core science and policy frameworks and how thresholds identified through transcriptomic evaluations provide evidence that can be more readily used by resource managers.
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Affiliation(s)
- Richard E Connon
- Department of Anatomy, Physiology & Cell Biology, School of Veterinary Medicine, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA
| | - Ken M Jeffries
- Department of Biological Sciences, University of Manitoba, 50 Sifton Road, Winnipeg, Manitoba, Canada R3T 2N2
| | - Lisa M Komoroske
- Marine Mammal and Turtle Division, Southwest Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, La Jolla, CA 92037, USA.,Department of Environmental Conservation, University of Massachusetts Amherst, Amherst, MA 01003, USA
| | - Anne E Todgham
- Department of Animal Science, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA
| | - Nann A Fangue
- Wildlife, Fish & Conservation Biology, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA
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19
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Davis BE, Komoroske LM, Hansen MJ, Poletto JB, Perry EN, Miller NA, Ehlman SM, Wheeler SG, Sih A, Todgham AE, Fangue NA. Juvenile rockfish show resilience to CO 2-acidification and hypoxia across multiple biological scales. Conserv Physiol 2018; 6:coy038. [PMID: 30018763 PMCID: PMC6041801 DOI: 10.1093/conphys/coy038] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Revised: 06/10/2018] [Accepted: 06/27/2018] [Indexed: 05/14/2023]
Abstract
California's coastal ecosystems are forecasted to undergo shifting ocean conditions due to climate change, some of which may negatively impact recreational and commercial fish populations. To understand if fish populations have the capacity to respond to multiple stressors, it is critical to examine interactive effects across multiple biological scales, from cellular metabolism to species interactions. This study examined the effects of CO2-acidification and hypoxia on two naturally co-occurring species, juvenile rockfish (genus Sebastes) and a known predator, cabezon (Scorpaenichthys marmoratus). Fishes were exposed to two PCO2 levels at two dissolved oxygen (DO) levels: ~600 (ambient) and ~1600 (high) μatm PCO2 and 8.0 (normoxic) and 4.5 mg l-1 DO (hypoxic) and assessments of cellular metabolism, prey behavior and predation mortality rates were quantified after 1 and 3 weeks. Physiologically, rockfish showed acute alterations in cellular metabolic enzyme activity after 1 week of acclimation to elevated PCO2 and hypoxia that were not evident in cabezon. Alterations in rockfish energy metabolism were driven by increases in anaerobic LDH activity, and adjustments in enzyme activity ratios of cytochrome c oxidase and citrate synthase and LDH:CS. Correlated changes in rockfish behavior were also apparent after 1 week of acclimation to elevated PCO2 and hypoxia. Exploration behavior increased in rockfish exposed to elevated PCO2 and spatial analysis of activity indicated short-term interference with anti-predator responses. Predation rate after 1 week increased with elevated PCO2; however, no mortality was observed under the multiple-stressor treatment suggesting negative effects on cabezon predators. Most noteworthy, metabolic and behavioral changes were moderately compensated after 3 weeks of acclimation, and predation mortality rates also decreased suggesting that these rockfish may be resilient to changes in environmental stressors predicted by climate models. Linking physiological and behavioral responses to multiple stressors is vital to understand impacts on populations and community dynamics.
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Affiliation(s)
- Brittany E Davis
- Department of Wildlife, Fish and Conservation Biology, University of California Davis, Davis, CA, USA
- Department of Animal Sciences, University of California Davis, Davis, CA, USA
| | - Lisa M Komoroske
- Department of Wildlife, Fish and Conservation Biology, University of California Davis, Davis, CA, USA
- Bodega Marine Laboratory, University of California Davis, Bodega Bay, CA, USA
- Department of Environmental Conservation, University of Massachusetts Amherst, Amherst, MA, USA
| | - Matthew J Hansen
- Department of Wildlife, Fish and Conservation Biology, University of California Davis, Davis, CA, USA
| | - Jamilynn B Poletto
- Department of Wildlife, Fish and Conservation Biology, University of California Davis, Davis, CA, USA
- School of Natural Resources, University of Nebraska, Lincoln, NE, USA
| | - Emily N Perry
- Department of Animal Sciences, University of California Davis, Davis, CA, USA
| | - Nathan A Miller
- Department of Wildlife, Fish and Conservation Biology, University of California Davis, Davis, CA, USA
| | - Sean M Ehlman
- Department of Environmental Science and Policy, University of California Davis, Davis, CA, USA
| | - Sarah G Wheeler
- Bodega Marine Laboratory, University of California Davis, Bodega Bay, CA, USA
- Department of Biology, San Diego State University, San Diego, CA, USA
| | - Andrew Sih
- Department of Environmental Science and Policy, University of California Davis, Davis, CA, USA
| | - Anne E Todgham
- Department of Animal Sciences, University of California Davis, Davis, CA, USA
| | - Nann A Fangue
- Department of Wildlife, Fish and Conservation Biology, University of California Davis, Davis, CA, USA
- Corresponding author: Department of Wildlife, Fish and Conservation Biology, University of California, Davis, CA 95616, USA. Tel: +(530) 752-4997;
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20
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Flynn EE, Todgham AE. Thermal windows and metabolic performance curves in a developing Antarctic fish. J Comp Physiol B 2017; 188:271-282. [PMID: 28988313 DOI: 10.1007/s00360-017-1124-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Revised: 09/04/2017] [Accepted: 09/11/2017] [Indexed: 10/18/2022]
Abstract
For ectotherms, temperature modifies the rate of physiological function across a temperature tolerance window depending on thermal history, ontogeny, and evolutionary history. Some adult Antarctic fishes, with comparatively narrow thermal windows, exhibit thermal plasticity in standard metabolic rate; however, little is known about the shape or breadth of thermal performance curves of earlier life stages of Antarctic fishes. We tested the effects of acute warming (- 1 to 8 °C) and temperature acclimation (2 weeks at - 1, 2, 4 °C) on survival and standard metabolic rate in early embryos of the dragonfish Gymnodraco acuticeps from McMurdo Sound, Ross Island, Antarctica. Contrary to predictions, embryos acclimated to warmer temperatures did not experience greater mortality and nearly all embryos survived acute warming to 8 °C. Metabolic performance curve height and shape were both significantly altered after 2 weeks of development at - 1 °C, with further increase in curve height, but not alteration of shape, with warm temperature acclimation. Overall metabolic rate temperature sensitivity (Q 10) from - 1 to 8 °C varied from 2.6 to 3.6, with the greatest thermal sensitivity exhibited by embryos at earlier developmental stages. Interclutch variation in metabolic rates, mass, and development of simultaneously collected embryos was also documented. Taken together, metabolic performance curves provide insight into the costs of early development under warming temperatures, with the potential for thermal sensitivity to be modified by dragonfish phenology and magnitude of seasonal changes in temperature.
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Affiliation(s)
- Erin E Flynn
- Department of Animal Sciences, University of California, Davis, CA, 95616, USA
| | - Anne E Todgham
- Department of Animal Sciences, University of California, Davis, CA, 95616, USA.
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21
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Drake MJ, Miller NA, Todgham AE. The role of stochastic thermal environments in modulating the thermal physiology of an intertidal limpet, Lottia digitalis. J Exp Biol 2017; 220:3072-3083. [DOI: 10.1242/jeb.159020] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2017] [Accepted: 06/12/2017] [Indexed: 12/24/2022]
Abstract
ABSTRACT
Much of our understanding of the thermal physiology of intertidal organisms comes from experiments with animals acclimated under constant conditions and exposed to a single heat stress. In nature, however, the thermal environment is more complex. Aerial exposure and the unpredictable nature of thermal stress during low tides may be critical factors in defining the thermal physiology of intertidal organisms. In the fingered limpet, Lottia digitalis, we investigated whether upper temperature tolerance and thermal sensitivity were influenced by the pattern of fluctuation with which thermal stress was applied. Specifically, we examined whether there was a differential response (measured as cardiac performance) to repeated heat stress of a constant and predictable magnitude compared with heat stress applied in a stochastic and unpredictable nature. We also investigated differences in cellular metabolism and damage following immersion for insights into biochemical mechanisms of tolerance. Upper temperature tolerance increased with aerial exposure, but no significant differences were found between predictable treatments of varying magnitudes (13°C versus 24°C versus 32°C). Significant differences in thermal tolerance were found between unpredictable trials with different heating patterns. There were no significant differences among treatments in basal citrate synthase activity, glycogen content, oxidative stress or antioxidants. Our results suggest that aerial exposure and recent thermal history, paired with relief from high low-tide temperatures, are important factors modulating the capacity of limpets to deal with thermal stress.
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Affiliation(s)
- Madeline J. Drake
- Department of Animal Science, University of California Davis, Davis, CA 95616, USA
| | - Nathan A. Miller
- Romberg Tiburon Center for Environmental Studies, San Francisco State University, Tiburon, CA 94920, USA
| | - Anne E. Todgham
- Department of Animal Science, University of California Davis, Davis, CA 95616, USA
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22
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Jeffries KM, Connon RE, Davis BE, Komoroske LM, Britton MT, Sommer T, Todgham AE, Fangue NA. Effects of high temperatures on threatened estuarine fishes during periods of extreme drought. J Exp Biol 2016; 219:1705-16. [DOI: 10.1242/jeb.134528] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2015] [Accepted: 03/15/2016] [Indexed: 12/17/2022]
Abstract
ABSTRACT
Climate change and associated increases in water temperatures may impact physiological performance in ectotherms and exacerbate endangered species declines. We used an integrative approach to assess the impact of elevated water temperature on two fishes of immediate conservation concern in a large estuary system, the threatened longfin smelt (Spirinchus thaleichthys) and endangered delta smelt (Hypomesus transpacificus). Abundances have reached record lows in California, USA, and these populations are at imminent risk of extirpation. California is currently impacted by a severe drought, resulting in high water temperatures, conditions that will become more common as a result of climate change. We exposed fish to environmentally relevant temperatures (14°C and 20°C) and used RNA sequencing to examine the transcriptome-wide responses to elevated water temperature in both species. Consistent with having a lower temperature tolerance, longfin smelt exhibited a pronounced cellular stress response, with an upregulation of heat shock proteins, after exposure to 20°C that was not observed in delta smelt. We detected an increase in metabolic rate in delta smelt at 20°C and increased expression of genes involved in metabolic processes and protein synthesis, patterns not observed in longfin smelt. Through examination of responses across multiple levels of biological organization, and by linking these responses to habitat distributions in the wild, we demonstrate that longfin smelt may be more susceptible than delta smelt to increases in temperatures, and they have little room to tolerate future warming in California. Understanding the species-specific physiological responses of sensitive species to environmental stressors is crucial for conservation efforts and managing aquatic systems globally.
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Affiliation(s)
- Ken M. Jeffries
- Anatomy, Physiology & Cell Biology, School of Veterinary Medicine, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA
- Wildlife, Fish & Conservation Biology, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA
| | - Richard E. Connon
- Anatomy, Physiology & Cell Biology, School of Veterinary Medicine, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA
| | - Brittany E. Davis
- Wildlife, Fish & Conservation Biology, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA
- Department of Animal Science, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA
| | - Lisa M. Komoroske
- Anatomy, Physiology & Cell Biology, School of Veterinary Medicine, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA
- Wildlife, Fish & Conservation Biology, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA
| | - Monica T. Britton
- Bioinformatics Core Facility, Genome Center, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA
| | - Ted Sommer
- California Department of Water Resources, Division of Environmental Services, P.O. Box 942836, Sacramento, CA 94236, USA
| | - Anne E. Todgham
- Department of Animal Science, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA
| | - Nann A. Fangue
- Wildlife, Fish & Conservation Biology, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA
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Chase DA, Flynn EE, Todgham AE. Survival, growth and stress response of juvenile tidewater goby, Eucyclogobius newberryi, to interspecific competition for food. Conserv Physiol 2016; 4:cow013. [PMID: 27293761 PMCID: PMC4845346 DOI: 10.1093/conphys/cow013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Revised: 02/27/2016] [Accepted: 03/16/2016] [Indexed: 06/06/2023]
Abstract
Reintroduction of endangered fishes to historic habitat has been used as a recovery tool; however, these fish may face competition from other fishes that established in their native habitat since extirpation. This study investigated the physiological response of tidewater goby, Eucyclogobius newberryi, an endangered California fish, when competing for food with threespine stickleback, Gasterosteus aculeatus, a native species, and rainwater killifish, Lucania parva, a non-native species. Survival, growth and physiological indicators of stress (i.e. cortisol, glucose and lactate concentrations) were assessed for juvenile fish held for 28 days in two food-limited conditions. When fed a 75% ration, survival of E. newberryi was significantly lower when held with G. aculeatus. In all fish assemblages, weight and relative condition decreased then stabilized over the 28 day experiment, while length remained unchanged. Whole-body cortisol in E. newberryi was not affected by fish assemblage; however, glucose and lactate concentrations were significantly higher with conspecifics than with other fish assemblages. When fed a 50% ration, survival of E. newberryi decreased during the second half of the experiment, while weight and relative condition decreased and length remained unchanged in all three fish assemblages. Cortisol concentrations were significantly higher for all fish assemblages compared with concentrations at the start of the experiment, whereas glucose and lactate concentrations were depressed relative to concentrations at the start of the experiment, with the magnitude of decrease dependent on the species assemblage. Our findings indicate that E. newberryi exhibited reduced growth and an elevated generalized stress response during low food availability. In response to reduced food availability, competition with G. aculeatus had the greatest physiological effect on E. newberryi, with minimal effects from the non-native L. parva. This study presents the first reported cortisol, glucose and lactate concentrations in response to chronic stress for E. newberryi.
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Affiliation(s)
- Daniel A Chase
- Department of Animal Science, University of California Davis, One Shields Avenue, Davis, CA 95616, USA
| | - Erin E Flynn
- Department of Animal Science, University of California Davis, One Shields Avenue, Davis, CA 95616, USA
| | - Anne E Todgham
- Department of Animal Science, University of California Davis, One Shields Avenue, Davis, CA 95616, USA
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Davis BE, Miller NA, Flynn EE, Todgham AE. Juvenile Antarctic rockcod (Trematomus bernacchii) are physiologically robust to CO2-acidified seawater. ACTA ACUST UNITED AC 2016; 219:1203-13. [PMID: 26944503 DOI: 10.1242/jeb.133173] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2015] [Accepted: 02/15/2016] [Indexed: 01/04/2023]
Abstract
To date, numerous studies have shown negative impacts of CO2-acidified seawater (i.e. ocean acidification, OA) on marine organisms, including calcifying invertebrates and fishes; however, limited research has been conducted on the physiological effects of OA on polar fishes and even less on the impact of OA on early developmental stages of polar fishes. We evaluated aspects of aerobic metabolism and cardiorespiratory physiology of juvenile emerald rockcod, ITALIC! Trematomus bernacchii, an abundant fish in the Ross Sea, Antarctica, to elevated partial pressure of carbon dioxide ( ITALIC! PCO2 ) [420 (ambient), 650 (moderate) and 1050 (high) μatm ITALIC! PCO2 ] over a 1 month period. We examined cardiorespiratory physiology, including heart rate, stroke volume, cardiac output and ventilation rate, whole organism metabolism via oxygen consumption rate and sub-organismal aerobic capacity by citrate synthase enzyme activity. Juvenile fish showed an increase in ventilation rate under high ITALIC! PCO2 compared with ambient ITALIC! PCO2 , whereas cardiac performance, oxygen consumption and citrate synthase activity were not significantly affected by elevated ITALIC! PCO2 Acclimation time had a significant effect on ventilation rate, stroke volume, cardiac output and citrate synthase activity, such that all metrics increased over the 4 week exposure period. These results suggest that juvenile emerald rockcod are robust to near-future increases in OA and may have the capacity to adjust for future increases in ITALIC! PCO2 by increasing acid-base compensation through increased ventilation.
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Affiliation(s)
- Brittany E Davis
- Department of Animal Sciences, University of California Davis, Davis, CA 95616, USA Department of Wildlife, Fish and Conservation Biology, University of California Davis, Davis, CA 95616, USA
| | - Nathan A Miller
- Department of Animal Sciences, University of California Davis, Davis, CA 95616, USA Romberg Tiburon Center for Environmental Studies, San Francisco State University, Tiburon, CA 94920, USA
| | - Erin E Flynn
- Department of Animal Sciences, University of California Davis, Davis, CA 95616, USA
| | - Anne E Todgham
- Department of Animal Sciences, University of California Davis, Davis, CA 95616, USA
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Todgham AE, Crombie TA, Hofmann GE. The effect of temperature adaptation on the ubiquitin-proteasome pathway in notothenioid fishes. J Exp Biol 2016; 220:369-378. [DOI: 10.1242/jeb.145946] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Accepted: 11/07/2016] [Indexed: 01/09/2023]
Abstract
There is an accumulating body of evidence suggesting that the sub-zero Antarctic marine environment places physiological constraints on protein homeostasis. Levels of ubiquitin (Ub)-conjugated proteins, 20S proteasome activity and mRNA expression of many proteins involved in both the ubiquitin (Ub) tagging of damaged proteins as well as the different complexes of the 26S proteasome were measured to examine whether there is thermal compensation of the Ub-proteasome pathway in Antarctic fishes to better understand the efficiency of the protein degradation machinery in polar species. Both Antarctic (Trematomus bernacchii, Pagothenia borchgrevinki) and non-Antarctic (Notothenia angustata, Bovichtus variegatus) notothenioids were included in this study to investigate the mechanisms of cold adaptation of this pathway in polar species. Overall, there were significant differences in the levels of Ub-conjugated proteins between the Antarctic notothenioids and B. variegatus, with N. angustata possessing levels very similar to the Antarctic fishes. Proteasome activity in the gills of Antarctic fishes demonstrated a high degree of temperature compensation such that activity levels were similar to activities measured in their temperate relatives at ecologically relevant temperatures. A similar level of thermal compensation of proteasome activity was not present in the liver of two Antarctic fishes. Higher gill proteasome activity is likely due in part to higher cellular levels of proteins involved in the Ub-proteasome pathway, as evidenced by high mRNA expression of relevant genes. Reduced activity of the Ub-proteasome pathway does not appear to be the mechanism responsible for elevated levels of denatured proteins in Antarctic fishes, at least in the gills.
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Affiliation(s)
- Anne E. Todgham
- Department of Animal Science, University of California, Davis, USA
| | | | - Gretchen E. Hofmann
- Department of Ecology, Evolution and Marine Biology, University of California, Santa Barbara, USA
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Bjelde BE, Miller NA, Stillman JH, Todgham AE. The Role of Oxygen in Determining Upper Thermal Limits in Lottia digitalis under Air Exposure and Submersion. Physiol Biochem Zool 2015; 88:483-93. [PMID: 26658246 DOI: 10.1086/682220] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Oxygen limitation of aerobic metabolism is hypothesized to drive organismal thermal tolerance limits. Differences in oxygen availability in air and water may underlie observed differences in upper thermal tolerance of intertidal limpets if oxygen is limiting in submerged environments. We explored how cardiac performance (heart rate, breakpoint temperature [BPT], flat-line temperature [FLT], and temperature sensitivity) was affected by hyperoxia and hypoxia in the finger limpet, Lottia digitalis, under air exposure and submersion. Upper thermal tolerance limits were unchanged by increasing availability of oxygen, although air-exposed limpets were able to maintain cardiac function to higher temperatures than submerged limpets. Maximum heart rate did not increase with greater partial pressure of oxygen (Po2), suggesting that tissue Po2 levels are likely maximized during normoxia. Hypoxia reduced breakpoint BPTs and FLTs in air-exposed and submerged limpets and accentuated the difference in BPTs between the two groups through greater reductions in BPT in submerged limpets. Differences in respiratory structures and the degree to which thermal limits are already maximized may play significant roles in determining how oxygen availability influences upper temperature tolerance.
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Affiliation(s)
- Brittany E Bjelde
- Department of Biology, San Francisco State University, San Francisco, California 94132; 2Department of Animal Science, University of California, Davis, California 95616; 3Romberg Tiburon Center for Environmental Studies, San Francisco State University, Tiburon, California 94920; 4Department of Integrative Biology, University of California, Berkeley, California 94720
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Flynn EE, Bjelde BE, Miller NA, Todgham AE. Ocean acidification exerts negative effects during warming conditions in a developing Antarctic fish. Conserv Physiol 2015; 3:cov033. [PMID: 27293718 PMCID: PMC4778439 DOI: 10.1093/conphys/cov033] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2015] [Revised: 06/16/2015] [Accepted: 06/18/2015] [Indexed: 05/30/2023]
Abstract
Anthropogenic CO2 is rapidly causing oceans to become warmer and more acidic, challenging marine ectotherms to respond to simultaneous changes in their environment. While recent work has highlighted that marine fishes, particularly during early development, can be vulnerable to ocean acidification, we lack an understanding of how life-history strategies, ecosystems and concurrent ocean warming interplay with interspecific susceptibility. To address the effects of multiple ocean changes on cold-adapted, slowly developing fishes, we investigated the interactive effects of elevated partial pressure of carbon dioxide (pCO2) and temperature on the embryonic physiology of an Antarctic dragonfish (Gymnodraco acuticeps), with protracted embryogenesis (∼10 months). Using an integrative, experimental approach, our research examined the impacts of near-future warming [-1 (ambient) and 2°C (+3°C)] and ocean acidification [420 (ambient), 650 (moderate) and 1000 μatm pCO2 (high)] on survival, development and metabolic processes over the course of 3 weeks in early development. In the presence of increased pCO2 alone, embryonic mortality did not increase, with greatest overall survival at the highest pCO2. Furthermore, embryos were significantly more likely to be at a later developmental stage at high pCO2 by 3 weeks relative to ambient pCO2. However, in combined warming and ocean acidification scenarios, dragonfish embryos experienced a dose-dependent, synergistic decrease in survival and developed more slowly. We also found significant interactions between temperature, pCO2 and time in aerobic enzyme activity (citrate synthase). Increased temperature alone increased whole-organism metabolic rate (O2 consumption) and developmental rate and slightly decreased osmolality at the cost of increased mortality. Our findings suggest that developing dragonfish are more sensitive to ocean warming and may experience negative physiological effects of ocean acidification only in the presence of an increased temperature. In addition to reduced hatching success, alterations in development and metabolism due to ocean warming and acidification could have negative ecological consequences owing to changes in phenology (i.e. early hatching) in the highly seasonal Antarctic ecosystem.
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Affiliation(s)
- Erin E Flynn
- Department of Biology, San Francisco State University, San Francisco, CA 94132, USA
- Department of Animal Sciences, University of California, Davis, CA 95616, USA
| | - Brittany E Bjelde
- Department of Animal Sciences, University of California, Davis, CA 95616, USA
| | - Nathan A Miller
- Department of Biology, San Francisco State University, San Francisco, CA 94132, USA
- Department of Animal Sciences, University of California, Davis, CA 95616, USA
| | - Anne E Todgham
- Department of Animal Sciences, University of California, Davis, CA 95616, USA
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Cheng BS, Bible JM, Chang AL, Ferner MC, Wasson K, Zabin CJ, Latta M, Deck A, Todgham AE, Grosholz ED. Testing local and global stressor impacts on a coastal foundation species using an ecologically realistic framework. Glob Chang Biol 2015; 21:2488-2499. [PMID: 25683857 DOI: 10.1111/gcb.12895] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2014] [Revised: 01/16/2015] [Accepted: 01/22/2015] [Indexed: 06/04/2023]
Abstract
Despite the abundance of literature on organismal responses to multiple environmental stressors, most studies have not matched the timing of experimental manipulations with the temporal pattern of stressors in nature. We test the interactive effects of diel-cycling hypoxia with both warming and decreased salinities using ecologically realistic exposures. Surprisingly, we found no evidence of negative synergistic effects on Olympia oyster growth; rather, we found only additive and opposing effects of hypoxia (detrimental) and warming (beneficial). We suspect that diel-cycling provided a temporal refuge that allowed physiological compensation. We also tested for latent effects of warming and hypoxia to low-salinity tolerance using a seasonal delay between stressor events. However, we did not find a latent effect, rather a threshold survival response to low salinity that was independent of early life-history exposure to warming or hypoxia. The absence of synergism is likely the result of stressor treatments that mirror the natural timing of environmental stressors. We provide environmental context for laboratory experimental data by examining field time series environmental data from four North American west coast estuaries and find heterogeneous environmental signals that characterize each estuary, suggesting that the potential stressor exposure to oysters will drastically differ over moderate spatial scales. This heterogeneity implies that efforts to conserve and restore oysters will require an adaptive approach that incorporates knowledge of local conditions. We conclude that studies of multiple environmental stressors can be greatly improved by integrating ecologically realistic exposure and timing of stressors found in nature with organismal life-history traits.
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Affiliation(s)
- Brian S Cheng
- Bodega Marine Laboratory, University of California, Davis, Davis, CA, USA
- Department of Environmental Science and Policy, University of California, Davis, Davis, CA, USA
| | - Jillian M Bible
- Bodega Marine Laboratory, University of California, Davis, Davis, CA, USA
- Department of Evolution and Ecology, University of California, Davis, Davis, CA, USA
| | - Andrew L Chang
- San Francisco Bay National Estuarine Research Reserve, Tiburon, CA, USA
| | - Matthew C Ferner
- San Francisco Bay National Estuarine Research Reserve, Tiburon, CA, USA
| | - Kerstin Wasson
- Elkhorn Slough National Estuarine Research Reserve, Watsonville, CA, USA
| | - Chela J Zabin
- Department of Environmental Science and Policy, University of California, Davis, Davis, CA, USA
| | - Marilyn Latta
- California State Coastal Conservancy, Oakland, CA, USA
| | - Anna Deck
- San Francisco Bay National Estuarine Research Reserve, Tiburon, CA, USA
| | - Anne E Todgham
- Department of Animal Science, University of California, Davis, Davis, CA, USA
| | - Edwin D Grosholz
- Bodega Marine Laboratory, University of California, Davis, Davis, CA, USA
- Department of Environmental Science and Policy, University of California, Davis, Davis, CA, USA
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McLean KM, Todgham AE. Effect of food availability on the growth and thermal physiology of juvenile Dungeness crabs (Metacarcinus magister). Conserv Physiol 2015; 3:cov013. [PMID: 27293698 PMCID: PMC4778468 DOI: 10.1093/conphys/cov013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/18/2014] [Revised: 02/27/2015] [Accepted: 03/01/2015] [Indexed: 06/06/2023]
Abstract
Juvenile Dungeness crabs spend ~1 year in the San Francisco Estuary, where they undergo considerable growth before returning to the coastal ocean. Previous studies suggest that competition, food scarcity and avoidance of conspecifics may cause some juvenile Dungeness crabs in the San Francisco Estuary to become food limited. Food limitation may force these crabs to forage in higher temperature intertidal environments in the estuary, exposing them to stressful conditions in order to sustain growth and, potentially, necessitating physiological trade-offs in energy allocation between growth and stress tolerance. To investigate the effects of food limitation on aerobic metabolism and physiological performance of crabs, we assessed growth, moulting frequency, metabolic rate, citrate synthase and malate dehydrogenase enzyme activity and cardiac performance, as an index of temperature sensitivity and upper temperature tolerance. Summer- and winter-caught crabs were acclimated to either a high- or a low-food ration for 5 weeks. Overall, our results demonstrated that while food limitation had a negative effect on growth of juvenile Dungeness crabs in both the summer and the winter feeding trials, crabs in the low-food group maintained both metabolic rate at ambient San Francisco Estuary temperatures (15°C; summer trial only) and upper temperature tolerance as determined by failure of cardiac function when compared with crabs in the high-food group (summer and winter trials). Therefore, the ability to maintain stress tolerance when food is limited appears to come as a physiological trade-off to growth. Food-limited crabs were unable to increase their metabolic rate to the same level as that achieved by well-fed crabs; therefore, if exposure to elevated temperatures persists and requires more energy than can be met by crabs in their food-limited state, physiological performance may be compromised.
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Affiliation(s)
- Katherine M. McLean
- Department of Biology, San Francisco State University, San Francisco, CA 94132, USA
| | - Anne E. Todgham
- Department of Biology, San Francisco State University, San Francisco, CA 94132, USA
- Department of Animal Science, University of California, Davis, CA 95616, USA
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Todgham AE, Stillman JH. Physiological responses to shifts in multiple environmental stressors: relevance in a changing world. Integr Comp Biol 2013; 53:539-44. [PMID: 23892371 DOI: 10.1093/icb/ict086] [Citation(s) in RCA: 197] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Population response to global change will depend on responses to a multivariate set of changes in abiotic habitat characteristics and biotic interactions. Organismal biologists seeking to make ecological inferences about the impacts of global change by studying physiological performance have traditionally performed carefully controlled experimental studies that examine one variable at a time. Those studies, while of high value, may not lead to accurate predictions of organismal responses in the natural habitat, where organisms experience concomitant changes in multiple environmental factors. The symposium "Physiological Responses to Simultaneous Shifts in Multiple Environmental Stressors: Relevance in a Changing World" focused on physiological studies in which multiple environmental variables were simultaneously examined and brought together an international group of early-career and established speakers with unique perspectives on studies of multistressors. In doing so, the objective of the symposium was to frame the necessary next steps for increasing predictive capacity of organismal responses to environmental shifts in the natural habitat, establish novel collaborations among researchers actively investigating physiological responses to a multivariate environment, and broaden the number of researchers conducting such studies.
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Affiliation(s)
- Anne E Todgham
- Department of Biology and Romberg Tiburon Center for Environmental Studies, San Francisco State University, San Francisco, CA 94132, USA
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Kültz D, Clayton DF, Robinson GE, Albertson C, Carey HV, Cummings ME, Dewar K, Edwards SV, Hofmann HA, Gross LJ, Kingsolver JG, Meaney MJ, Schlinger BA, Shingleton AW, Sokolowski MB, Somero GN, Stanzione DC, Todgham AE. New Frontiers for Organismal Biology. Bioscience 2013. [DOI: 10.1525/bio.2013.63.6.8] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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Fangue NA, Osborne EJ, Todgham AE, Schulte PM. The Onset Temperature of the Heat-Shock Response and Whole-Organism Thermal Tolerance Are Tightly Correlated in both Laboratory-Acclimated and Field-Acclimatized Tidepool Sculpins (Oligocottus maculosus). Physiol Biochem Zool 2011; 84:341-52. [DOI: 10.1086/660113] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Abstract
Rising atmospheric carbon dioxide has resulted in scientific projections of changes in global temperatures, climate in general, and surface seawater chemistry. Although the consequences to ecosystems and communities of metazoans are only beginning to be revealed, a key to forecasting expected changes in animal communities is an understanding of species' vulnerability to a changing environment. For example, environmental stressors may affect a particular species by driving that organism outside a tolerance window, by altering the costs of metabolic processes under the new conditions, or by changing patterns of development and reproduction. Implicit in all these examples is the foundational understanding of physiological mechanisms and how a particular environmental driver (e.g., temperature and ocean acidification) will be transduced through the animal to alter tolerances and performance. In this review, we highlight examples of mechanisms, focusing on those underlying physiological plasticity, that operate in contemporary organisms as a means to consider physiological responses that are available to organisms in the future.
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Affiliation(s)
- Gretchen E Hofmann
- Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, CA 93106-9620, USA.
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Todgham AE, Hofmann GE. Transcriptomic response of sea urchin larvae Strongylocentrotus purpuratus to CO2-driven seawater acidification. J Exp Biol 2009; 212:2579-94. [DOI: 10.1242/jeb.032540] [Citation(s) in RCA: 214] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
SUMMARY
Ocean acidification from the uptake of anthropogenic CO2 is expected to have deleterious consequences for many calcifying marine animals. Forecasting the vulnerability of these marine organisms to climate change is linked to an understanding of whether species possess the physiological capacity to compensate for the potentially adverse effects of ocean acidification. We carried out a microarray-based transcriptomic analysis of the physiological response of larvae of a calcifying marine invertebrate, the purple sea urchin, Strongylocentrotus purpuratus, to CO2-driven seawater acidification. In lab-based cultures, larvae were raised under conditions approximating current ocean pH conditions (pH 8.01) and at projected, more acidic pH conditions (pH 7.96 and 7.88) in seawater aerated with CO2 gas. Targeting expression of ∼1000 genes involved in several biological processes, this study captured changes in gene expression patterns that characterize the transcriptomic response to CO2-driven seawater acidification of developing sea urchin larvae. In response to both elevated CO2 scenarios, larvae underwent broad scale decreases in gene expression in four major cellular processes:biomineralization, cellular stress response, metabolism and apoptosis. This study underscores that physiological processes beyond calcification are impacted greatly, suggesting that overall physiological capacity and not just a singular focus on biomineralization processes is essential for forecasting the impact of future CO2 conditions on marine organisms. Conducted on targeted and vulnerable species, genomics-based studies, such as the one highlighted here, have the potential to identify potential `weak links' in physiological function that may ultimately determine an organism's capacity to tolerate future ocean conditions.
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Affiliation(s)
- Anne E. Todgham
- Department of Ecology, Evolution, and Marine Biology, University of California Santa Barbara, Santa Barbara, CA 93106, USA
| | - Gretchen E. Hofmann
- Department of Ecology, Evolution, and Marine Biology, University of California Santa Barbara, Santa Barbara, CA 93106, USA
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Abstract
The ability of an organism to acquire O(2) from its environment is key to survival and can play an important role in dictating a species' ecological distribution. This study is the first, to our knowledge, to show a tight, phylogenetically independent correlation between hypoxia tolerance, traits involved in dictating O(2) extraction capacity and the distribution of a group of closely related fish species, sculpins from the family Cottidae, along the nearshore marine environment. Sculpins with higher hypoxia tolerance, measured as low critical O(2) tensions (P(crit)), inhabit the O2 variable intertidal zones, while species with lower hypoxia tolerance inhabit the more O(2) stable subtidal zone or freshwater. Hypoxia tolerance is phylogenetically independently associated with an enhanced O(2) extraction capacity, with three principal components accounting for 75 per cent of the variation in P(crit): routine O(2) consumption rate; mass-specific gill surface area; and whole blood haemoglobin (Hb)- O(2)-binding affinity (P(50)). Variation in whole blood Hb-O(2)P(50) is strongly correlated with the intrinsic O(2)-binding properties of the purified Hb while the differences in the concentration of the allosteric Hb modulators, ATP and GTP, provide a Hb system with substantial plasticity for survival in a highly O(2) variable environment.
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Affiliation(s)
- Milica Mandic
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z4
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Todgham AE, Hoaglund EA, Hofmann GE. Is cold the new hot? Elevated ubiquitin-conjugated protein levels in tissues of Antarctic fish as evidence for cold-denaturation of proteins in vivo. J Comp Physiol B 2007; 177:857-66. [PMID: 17710411 DOI: 10.1007/s00360-007-0183-2] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2007] [Revised: 06/20/2007] [Accepted: 06/21/2007] [Indexed: 11/25/2022]
Abstract
Levels of ubiquitin (Ub)-conjugated proteins, as an index of misfolded or damaged proteins, were measured in notothenioid fishes, with both Antarctic (Trematomus bernacchii, T. pennellii, Pagothenia borchgrevinki) and non-Antarctic (Notothenia angustata, Bovichtus variegatus) distributions, as well as non-notothenioid fish from the Antarctic (Lycodichthys dearborni, Family Zoarcidae) and New Zealand (Bellapiscis medius, Family Tripterygiidae), in an effort to better understand the effect that inhabiting a sub-zero environment has on maintaining the integrity of the cellular protein pool. Overall, levels of Ub-conjugated proteins in cold-adapted Antarctic fishes were significantly higher than New Zealand fishes in gill, liver, heart and spleen tissues suggesting that life at sub-zero temperatures impacts protein homeostasis. The highest tissue levels of ubiquitinated proteins were found in the spleen of all fish. Ub conjugate levels in the New Zealand N. angustata, more closely resembled levels measured in other Antarctic fishes than levels measured in other New Zealand species, likely reflecting their recent shared ancestry with Antarctic notothenioids.
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Affiliation(s)
- Anne E Todgham
- Department of Ecology, Evolution and Marine Biology, University of California-Santa Barbara, Santa Barbara, CA 93106-9610, USA
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Todgham AE, Iwama GK, Schulte PM. Effects of the Natural Tidal Cycle and Artificial Temperature Cycling on Hsp Levels in the Tidepool SculpinOligocottus maculosus. Physiol Biochem Zool 2006; 79:1033-45. [PMID: 17041869 DOI: 10.1086/507664] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/01/2006] [Indexed: 11/03/2022]
Abstract
The rocky intertidal zone is characterized by a predictable cycle of environmental change cued by the ebb and flow of the tides. Tidepools are thus an excellent environment in which to determine whether predictability of environmental change can entrain an endogenous rhythmicity in heat shock protein (Hsp) levels. In this study, we monitored changes in Hsp mRNA and protein levels that occurred over the tidal cycle in tidepool sculpins and investigated whether there was an endogenous tidal rhythm in Hsp expression that persisted once the sculpins were transferred to a stable environment. Fluctuations in the tidepool environment increased hsc70, hsp70, and hsp90 mRNA levels, which translated into increased Hsc/Hsp70 and Hsp90 protein levels; however, this was not due to an endogenous tidal rhythm in Hsp levels because sculpins held under constant conditions did not show any rhythmicity in the expression of these genes. By exposing sculpins to an artificial temperature cycling regime that mimicked the temperature changes of a mid-intertidal pool, we were able to account for the direct role of temperature in regulating Hsp expression. However, there are additional extrinsic factors that likely integrate with temperature and result in differences between the hsp induction profiles that were observed in sculpins inhabiting their natural environment and those in cycling conditions in the laboratory.
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Affiliation(s)
- Anne E Todgham
- Faculty of Agricultural Sciences, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
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Todgham AE, Schulte PM, Iwama GK. Cross‐Tolerance in the Tidepool Sculpin: The Role of Heat Shock Proteins. Physiol Biochem Zool 2005; 78:133-44. [PMID: 15778933 DOI: 10.1086/425205] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/26/2004] [Indexed: 11/03/2022]
Abstract
Cross-tolerance, or the ability of one stressor to transiently increase tolerance to a second heterologous stressor, is thought to involve the induction of heat shock proteins (Hsp). We thus investigated the boundaries of cross-tolerance in tidepool sculpins (Oligocottus maculosus) and their relationship to Hsp70 levels. Survival of sculpins exposed to severe osmotic (90 ppt, 2 h) and hypoxic (0.33 mg O(2)/L, 2 h) stressors increased from 68% to 96%, and from 47% to 76%, respectively, following a +12 degrees C heat shock. The magnitude of this heat shock was critical for protection. A +10 degrees C heat shock did not confer cross-tolerance, while a +15 degrees C heat shock was deleterious. Sculpins required between 8 and 48 h of recovery following the +12 degrees C heat shock to develop cross-tolerance. There was no association between Hsp70 levels before the onset of the secondary stressor and cross-tolerance. However, branchial Hsp70 levels following osmotic shock were highly correlated with the time frame of cross-tolerance. Thus, Hsp70 induction by the priming stressor may be less important than the ability of the cell to mount an Hsp response to subsequent stressors. The time frame of cross-tolerance is similar to the interval between low tides, suggesting the possible relevance of this response in nature.
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Affiliation(s)
- Anne E Todgham
- Faculty of Agricultural Sciences, University of British Columbia, Vancouver, Canada.
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Abstract
Despite decades of intensive investigation, important questions remain regarding the functional, ecological, and evolutionary roles of heat shock proteins. In this paper, we discuss the utility of fish as a model system to address these questions, and review the relevant studies of heat shock protein genes and the regulation of their expression in fish. Although molecular studies of the heat shock proteins in fish are still in their early descriptive phase, data are rapidly being collected. More is known about the biotic and abiotic factors regulating heat shock proteins. We briefly review these studies and focus on the role of heat shock proteins in development, their regulation by the endocrine system, and their importance in fish in nature. Functional genomics approaches will provide the tools necessary to gain a comprehensive understanding of the significance of heat shock proteins in the cellular stress response, in the physiological processes at higher levels of organization, and in the whole animal in its natural environment.
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Affiliation(s)
- N Basu
- Faculty of Agricultural Sciences and AquaNet, University of British Columbia, Vancouver, BC, Canada
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Gamperl AK, Todgham AE, Parkhouse WS, Dill R, Farrell AP. Recovery of trout myocardial function following anoxia: preconditioning in a non-mammalian model. Am J Physiol Regul Integr Comp Physiol 2001; 281:R1755-63. [PMID: 11705758 DOI: 10.1152/ajpregu.2001.281.6.r1755] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Studies with mammals and birds clearly demonstrate that brief preexposure to oxygen deprivation can protect the myocardium from damage normally associated with a subsequent prolonged hypoxic/ischemic episode. However, is not known whether this potent mechanism of myocardial protection, termed preconditioning, exists in other vertebrates including fishes. In this study, we used an in situ trout (Oncorhynchus mykiss) working heart preparation at 10 degrees C to examine whether prior exposure to 5 min of anoxia (PO(2) < or = 5 mmHg) could reduce or eliminate the myocardial dysfunction that normally follows 15 min of anoxic exposure. Hearts were exposed either to a control treatment (oxygenated perfusion) or to one of three anoxic treatments: 1) anoxia with low P(out) [15 min of anoxia at an output pressure (P(out)) of 10 cmH(2)O]; 2) anoxia with high P(out) [10 min of anoxia at a P(out) of 10 cmH(2)O, followed by 5 min of anoxia at P(out) = 50 cmH(2)O]; and 3) preconditioning [5 min of anoxia at P(out) = 10 cmH(2)O, followed after 20 min of oxygenated perfusion by the protocol described for the anoxia with high P(out) group]. Changes in maximum cardiac function, measured before and after anoxic exposure, were used to assess myocardial damage. Maximum cardiac performance of the control group was unaffected by the experimental protocol, whereas 15 min of anoxia at low P(out) decreased maximum stroke volume (V(s max)) by 15% and maximum cardiac output (Q(max)) by 23%. When the anoxic workload was increased by raising P(out) to 50 cmH(2)O, these parameters were decreased further (by 23 and 38%, respectively). Preconditioning with anoxia completely prevented the reductions in V(s max) and Q(max) that were observed in the anoxia with high P(out) group and any anoxia-related increases in the input pressure (P(in)) required to maintain resting Q (16 ml. min(-1). kg(-1)). Myocardial levels of glycogen and lactate were not affected by any of the experimental treatments; however, lactate efflux was sevenfold higher in the preconditioned hearts. These data strongly suggest that 1) a preconditioning-like mechanism exists in the rainbow trout heart, 2) increased anaerobic glycolysis, fueled by exogenous glucose, was associated with anoxic preconditioning, and 3) preconditioning represents a fundamental mechanism of cardioprotection that appeared early in the evolution of vertebrates.
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Affiliation(s)
- A K Gamperl
- Department of Biological Sciences, Simon Fraser University, Burnaby, British Columbia, Canada V5A 1S6.
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Todgham AE, Anderson PM, Wright PA. Effects of exercise on nitrogen excretion, carbamoyl phosphate synthetase III activity and related urea cycle enzymes in muscle and liver tissues of juvenile rainbow trout (Oncorhynchus mykiss). Comp Biochem Physiol A Mol Integr Physiol 2001; 129:527-39. [PMID: 11423323 DOI: 10.1016/s1095-6433(01)00290-2] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The purpose of this study was to determine if carbamoyl phosphate synthetase III (CPSase III) and related urea cycle enzyme activities in skeletal muscle tissue of juvenile rainbow trout (Oncorhynchus mykiss) increase during short- or long-term exercise, in parallel with changes in whole-body urea excretion rates. Urea excretion was elevated by 65% in fish that swam at high-speed (50 cm/s) vs. low-speed (20 cm/s) over a 2-h period, with no significant changes in CPSase III, ornithine transcarbamoylase or glutamine synthetase activities in muscle tissue. Fish that swam for 4 days at high-speed had higher rates of ammonia excretion and GSase activity in muscle and liver tissue relative to low-speed swimmers. Calculations showed that 47-53% of excreted urea, theoretically could be accounted for by total muscle CPSase III activity in juvenile and adult trout. The data indicate that increases in the rate of urea excretion during short-term high intensity exercise are not linked to higher activities of urea cycle enzymes in muscle tissue, but this does not rule out the possibility of increased flux through muscle CPSase III and related enzymes. Furthermore, these results indicate that urea cycle enzyme activities in skeletal muscle tissue can account for a significant portion of total urea excretion in juvenile and adult trout.
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Affiliation(s)
- A E Todgham
- Department of Zoology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
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