Publications by year
In Press
Salter MA, Harborne AR, Perry CT, Wilson RW (In Press). Phase heterogeneity in carbonate production by marine fish influences their roles in sediment generation and the inorganic carbon cycle. Scientific Reports
Salter MA, Perry CT, Stuart-Smith R, Edgar GJ, Wilson RW, Harborne AR (In Press). Reef fish carbonate production assessments highlight regional variation in sedimentary significance. Geology
Salter MA, Perry C, Stuart-Smith RD, Edgar GJ, Wilson R, Harborne AR (In Press). Reef fish carbonate production assessments highlight regional variation in sedimentary significance (DATASET).
GeologyAbstract:
Reef fish carbonate production assessments highlight regional variation in sedimentary significance (DATASET)
Dataset for Salter et al. (2018) "Reef fish carbonate production assessments highlight regional variation in sedimentary significance" published in GEOLOGY
Abstract.
2023
Davison WG, Cooper CA, Sloman KA, Wilson RW (2023). A method for measuring meaningful physiological variables in fish blood without surgical cannulation.
Sci Rep,
13(1).
Abstract:
A method for measuring meaningful physiological variables in fish blood without surgical cannulation.
Gaining meaningful blood samples from water-breathing fish is a significant challenge. Two main methods typically used are grab 'n' stab and surgical cannulation. Both methods have benefits, but also significant limitations under various scenarios. Here we present a method of blood sampling laboratory fish involving gradual induction of anaesthesia within their home tank, avoiding physical struggling associated with capture, followed by rapid transfer to a gill irrigation system to maintain artificial ventilation via adequate gill water flow and then followed by sampling the caudal vasculature. This method negates many blood chemistry disturbances associated with grab 'n' stab (i.e. low pH and oxygen, elevated lactate, CO2 and stress hormones) and generates results that are directly comparable to cannulated fish under a wide range of experimentally-induced acid-base scenarios (acidosis and alkalosis). Crucially this method was successful in achieving accurate acid-base blood measurements from fish ten times smaller than are typically suitable for cannulation. This opens opportunities not previously possible for studies that relate to basic physiology, sustainable aquaculture, ecotoxicology, conservation, and climate change.
Abstract.
Author URL.
Ghilardi M, Salter MA, Parravicini V, Ferse SCA, Rixen T, Wild C, Birkicht M, Perry CT, Berry A, Wilson RW, et al (2023). Temperature, species identity and morphological traits predict carbonate excretion and mineralogy in tropical reef fishes.
Nature Communications,
14(1).
Abstract:
Temperature, species identity and morphological traits predict carbonate excretion and mineralogy in tropical reef fishes
AbstractAnthropogenic pressures are restructuring coral reefs globally. Sound predictions of the expected changes in key reef functions require adequate knowledge of their drivers. Here we investigate the determinants of a poorly-studied yet relevant biogeochemical function sustained by marine bony fishes: the excretion of intestinal carbonates. Compiling carbonate excretion rates and mineralogical composition from 382 individual coral reef fishes (85 species and 35 families), we identify the environmental factors and fish traits that predict them. We find that body mass and relative intestinal length (RIL) are the strongest predictors of carbonate excretion. Larger fishes and those with longer intestines excrete disproportionately less carbonate per unit mass than smaller fishes and those with shorter intestines. The mineralogical composition of excreted carbonates is highly conserved within families, but also controlled by RIL and temperature. These results fundamentally advance our understanding of the role of fishes in inorganic carbon cycling and how this contribution will change as community composition shifts under increasing anthropogenic pressures.
Abstract.
2022
Verberk WCEP, Sandker JF, van de Pol ILE, Urbina MA, Wilson RW, McKenzie DJ, Leiva FP (2022). Body mass and cell size shape the tolerance of fishes to low oxygen in a temperature-dependent manner.
GLOBAL CHANGE BIOLOGY,
28(19), 5695-5707.
Author URL.
Goodrich HR, Berry AA, Montgomery DW, Davison WG, Wilson RW (2022). Fish feeds supplemented with calcium-based buffering minerals decrease stomach acidity, increase the blood alkaline tide and cost more to digest.
Sci Rep,
12(1).
Abstract:
Fish feeds supplemented with calcium-based buffering minerals decrease stomach acidity, increase the blood alkaline tide and cost more to digest.
Predatory fish in the wild consume whole prey including hard skeletal parts like shell and bone. Shell and bone are made up of the buffering minerals calcium carbonate (CaCO3) and calcium phosphate (Ca3(PO4)2). These minerals resist changes in pH, meaning they could have physiological consequences for gastric acidity, digestion and metabolism in fish. Using isocaloric diets supplemented with either CaCO3, Ca3(PO4)2 or CaCl2 as non-buffering control, we investigated the impacts of dietary buffering on the energetic cost of digestion (i.e. specific dynamic action or SDA), gastric pH, the postprandial blood alkalosis (the "alkaline tide") and growth in juvenile rainbow trout (Oncorhynchus mykiss). Increases in dietary buffering were significantly associated with increased stomach chyme pH, postprandial blood HCO3-, net base excretion, the total SDA and peak SDA but did not influence growth efficiency in a 21 day trial. This result shows that aspects of a meal that have no nutritional value can influence the physiological and energetic costs associated with digestion in fish, but that a reduction in the SDA will not always lead to improvements in growth efficiency. We discuss the broader implications of these findings for the gastrointestinal physiology of fishes, trade-offs in prey choice in the wild, anthropogenic warming and feed formulation in aquaculture.
Abstract.
Author URL.
Schvezov N, Wilson RW, Urbina MA (2022). Oxidative damages and antioxidant defences after feeding a single meal in rainbow trout.
Journal of Comparative Physiology B: Biochemical, Systemic, and Environmental Physiology,
192(3-4), 459-471.
Abstract:
Oxidative damages and antioxidant defences after feeding a single meal in rainbow trout
Feeding and digestion are metabolically demanding causing a rise on metabolic rate called Specific Dynamic Action (SDA). Although SDA has been vastly reported in fish, its potential consequences on the oxidative-antioxidant balance has not been evaluated to date in fish, a model with a long alkaline tide associated with feeding as well. Using rainbow trout (Oncorhynchus mykiss) as a model species, the aims of the present study were to: (1) assess potential oxidative damages and changes in oxidative defences after feeding on a single meal, and (2) identify the timescale of such changes over a 96 h post-feeding period. Oxidative damage in proteins and lipids and the activities of four enzymatic antioxidant defences: superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and glutathione-S-transferase (GST) were measured in gill, stomach, intestine and liver. DNA damage was measured in red blood cells. Fish were sampled before and after 1.5, 6, 24, 48, 72 and 96 h of ingestion of a 3% body mass ration. Trends of post-prandial damage were present in all tissues, but only protein oxidation varied significatively during digestion in the stomach. The intestine and stomach presented the highest enzymatic activities, likely due to the high metabolic action that these tissues have during digestion, with peaks during post-feeding: at 24 h of SOD in stomach and at 48 h of CAT in intestine. Observed GPx peaks during post-feeding in gills are likely due to the exacerbated demands for ion fluxes and/or oxygen during feeding. The differential response of the antioxidant system observed in tissues of rainbow trout during digestion indicates a coordinated and tissue-specific antioxidant defence.
Abstract.
Montgomery D, Kwan G, Davison W, Finlay J, Berry A, Simpson S, Engelhard G, Birchenough S, Tresguerres M, Wilson R, et al (2022). Rapid blood acid-base regulation by European sea bass (Dicentrarchus labrax) in response to sudden exposure to high environmental CO2.
Abstract:
Rapid blood acid-base regulation by European sea bass (Dicentrarchus labrax) in response to sudden exposure to high environmental CO2
Fish in coastal ecosystems can be exposed to acute variations in CO2 of between 0.2-1 kPa CO2 (2,000 - 10,000 µatm). Coping with this environmental challenge will depend on the ability to rapidly compensate the internal acid-base disturbance caused by sudden exposure to high environmental CO2 (blood and tissue acidosis); however, studies about the speed of acid-base regulatory responses in marine fish are scarce. We observed that upon sudden exposure to ~1 kPa CO2, European sea bass (Dicentrarchus labrax) completely regulate erythrocyte intracellular pH within ~40 minutes, thus restoring haemoglobin-O2 affinity to pre-exposure levels. Moreover, blood pH returned to normal levels within ~2 hours, which is one of the fastest acid-base recoveries documented in any fish. This was achieved via a large upregulation of net acid excretion and accumulation of HCO3- in blood, which increased from ~4 to ~22 mM. While the abundance and intracellular localisation of gill Na+/K+-ATPase (NKA) and Na+/H+ exchanger 3 (NHE3) remained unchanged, the apical surface area of acid-excreting gill ionocytes doubled. This constitutes a novel mechanism for rapidly increasing acid excretion during sudden blood acidosis. Rapid acid-base regulation was completely prevented when the same high CO2 exposure occurred in seawater with experimentally reduced HCO3- and pH, likely because reduced environmental pH inhibited gill H+ excretion via NHE3. The rapid and robust acid-base regulatory responses identified will enable European sea bass to maintain physiological performance during large and sudden CO2 fluctuations that naturally occur in coastal environments.
Abstract.
Montgomery DW, Kwan GT, Davison WG, Finlay J, Berry A, Simpson SD, Engelhard GH, Birchenough SNR, Tresguerres M, Wilson RW, et al (2022). Rapid blood acid-base regulation by European sea bass (Dicentrarchus labrax) in response to sudden exposure to high environmental CO2.
J Exp Biol,
225(2).
Abstract:
Rapid blood acid-base regulation by European sea bass (Dicentrarchus labrax) in response to sudden exposure to high environmental CO2.
Fish in coastal ecosystems can be exposed to acute variations in CO2 of between 0.2 and 1
kPa CO2 (2000-10,000
µatm). Coping with this environmental challenge will depend on the ability to rapidly compensate for the internal acid-base disturbance caused by sudden exposure to high environmental CO2 (blood and tissue acidosis); however, studies about the speed of acid-base regulatory responses in marine fish are scarce. We observed that upon sudden exposure to ∼1
kPa CO2, European sea bass (Dicentrarchus labrax) completely regulate erythrocyte intracellular pH within ∼40
min, thus restoring haemoglobin-O2 affinity to pre-exposure levels. Moreover, blood pH returned to normal levels within ∼2
h, which is one of the fastest acid-base recoveries documented in any fish. This was achieved via a large upregulation of net acid excretion and accumulation of HCO3- in blood, which increased from ∼4 to ∼22
mmol
l-1. While the abundance and intracellular localisation of gill Na+/K+-ATPase (NKA) and Na+/H+ exchanger 3 (NHE3) remained unchanged, the apical surface area of acid-excreting gill ionocytes doubled. This constitutes a novel mechanism for rapidly increasing acid excretion during sudden blood acidosis. Rapid acid-base regulation was completely prevented when the same high CO2 exposure occurred in seawater with experimentally reduced HCO3- and pH, probably because reduced environmental pH inhibited gill H+ excretion via NHE3. The rapid and robust acid-base regulatory responses identified will enable European sea bass to maintain physiological performance during large and sudden CO2 fluctuations that naturally occur in coastal environments.
Abstract.
Author URL.
2021
Pinheiro JPS, Windsor FM, Wilson RW, Tyler CR (2021). Global variation in freshwater physico-chemistry and its influence on chemical toxicity in aquatic wildlife.
Biol Rev Camb Philos Soc,
96(4), 1528-1546.
Abstract:
Global variation in freshwater physico-chemistry and its influence on chemical toxicity in aquatic wildlife.
Chemical pollution is one of the major threats to global freshwater biodiversity and will be exacerbated through changes in temperature and rainfall patterns, acid-base chemistry, and reduced freshwater availability due to climate change. In this review we show how physico-chemical features of natural fresh waters, including pH, temperature, oxygen, carbon dioxide, divalent cations, anions, carbonate alkalinity, salinity and dissolved organic matter, can affect the environmental risk to aquatic wildlife of pollutant chemicals. We evidence how these features of freshwater physico-chemistry directly and/or indirectly affect the solubility, speciation, bioavailability and uptake of chemicals [including via alterations in the trans-epithelial electric potential (TEP) across the gills or skin] as well as the internal physiology/biochemistry of the organisms, and hence ultimately toxicity. We also show how toxicity can vary with species and ontogeny. We use a new database of global freshwater chemistry (GLORICH) to demonstrate the huge variability (often >1000-fold) for these physico-chemical variables in natural fresh waters, and hence their importance to ecotoxicology. We emphasise that a better understanding of chemical toxicity and more accurate environmental risk assessment requires greater consideration of the natural water physico-chemistry in which the organisms we seek to protect live.
Abstract.
Author URL.
Montgomery DW, Kwan GT, Davison WG, Finlay J, Berry A, Simpson SD, Engelhard GH, Birchenough SNR, Tresguerres M, Wilson RW, et al (2021). Rapid blood acid-base regulation by European sea bass (Dicentrarchus labrax) in response to sudden exposure to high environmental CO2.
Saba GK, Burd AB, Dunne JP, Hernández-León S, Martin AH, Rose KA, Salisbury J, Steinberg DK, Trueman CN, Wilson RW, et al (2021). Toward a better understanding of fish-based contribution to ocean carbon flux.
Limnology and Oceanography,
66(5), 1639-1664.
Abstract:
Toward a better understanding of fish-based contribution to ocean carbon flux
Fishes are the dominant vertebrates in the ocean, yet we know little of their contribution to carbon export flux at regional to global scales. We synthesize the existing information on fish-based carbon flux in coastal and pelagic waters, identify gaps and challenges in measuring this flux and approaches to address them, and recommend research priorities. Based on our synthesis of passive (fecal pellet sinking) and active (migratory) flux of fishes, we estimated that fishes contribute an average (± standard deviation) of about 16.1% (± 13%) to total carbon flux out of the euphotic zone. Using the mean value of model-generated global carbon flux estimates, this equates to an annual flux of 1.5 ± 1.2 Pg C yr−1. High variability in estimations of the fish-based contribution to total carbon flux among previous field studies and reported here highlight significant methodological variations and observational gaps in our present knowledge. Community-adopted methodological standards, improved and more frequent measurements of biomass and passive and active fluxes of fishes, and stronger linkages between observations and models will decrease uncertainty, increase our confidence in the estimation of fish-based carbon flux, and enable identification of controlling factors to account for spatial and temporal variability. Better constraints on this key component of the biological pump will provide a baseline for understanding how ongoing climate change and harvest will affect the role fishes play in carbon flux.
Abstract.
2019
Mangan S, Wilson R, Findlay H, Lewis CN (2019). Acid–base physiology over tidal periods in the mussel Mytilus edulis: size and temperature are more influential than seawater pH. Proceedings of the Royal Society B: Biological Sciences, 286
Montgomery DW, Simpson SD, Engelhard GH, Birchenough SNR, Wilson RW (2019). Rising CO2 enhances hypoxia tolerance in a marine fish.
Scientific Reports,
9(1).
Abstract:
Rising CO2 enhances hypoxia tolerance in a marine fish
AbstractGlobal environmental change is increasing hypoxia in aquatic ecosystems. During hypoxic events, bacterial respiration causes an increase in carbon dioxide (CO2) while oxygen (O2) declines. This is rarely accounted for when assessing hypoxia tolerances of aquatic organisms. We investigated the impact of environmentally realistic increases in CO2 on responses to hypoxia in European sea bass (Dicentrarchus labrax). We conducted a critical oxygen (O2crit) test, a common measure of hypoxia tolerance, using two treatments in which O2 levels were reduced with constant ambient CO2 levels (~530 µatm), or with reciprocal increases in CO2 (rising to ~2,500 µatm). We also assessed blood acid-base chemistry and haemoglobin-O2 binding affinity of sea bass in hypoxic conditions with ambient (~650 μatm) or raised CO2 (~1770 μatm) levels. Sea bass exhibited greater hypoxia tolerance (~20% reduced O2crit), associated with increased haemoglobin-O2 affinity (~32% fall in P50) of red blood cells, when exposed to reciprocal changes in O2 and CO2. This indicates that rising CO2 which accompanies environmental hypoxia facilitates increased O2 uptake by the blood in low O2 conditions, enhancing hypoxia tolerance. We recommend that when impacts of hypoxia on aquatic organisms are assessed, due consideration is given to associated environmental increases in CO2.
Abstract.
Corbett WT (2019). The Behavioural and Physiological Effects of Pile-driving Noise on Marine Species.
Abstract:
The Behavioural and Physiological Effects of Pile-driving Noise on Marine Species
Anthropogenic noise is a recognised pollutant in both terrestrial and aquatic environments. Noise levels in the ocean have risen greatly over the past few decades. The principal low-frequency background noise in the oceans is generated by commercial shipping, and can have a profound impact on fitness in a variety of marine species. Additionally, the loud impulsive noise from industrial pile-driving activity is increasingly prevalent in the oceans due to the recent development of offshore windfarms to meet renewable energy targets. Little research has explored the impact that this noise is having on marine species, especially invertebrates. The aim of this thesis is to explore the physiological and behavioural responses of marine species to playback of pile-driving noise, using playback of ambient marine sound as a control. The first study aimed to assess the physiological and behavioural response of the decapod crustacean Carcinus maenas to pile-driving noise playback in experimental tanks. In the physiological experiment, crabs did not significantly differ in their oxygen consumption or haemolymph parameters in response to pile-driving noise and ambient sound. However, in the behavioural feeding experiment, crab behaviour was significantly altered during pile-driving playback, including increased time spent immobile and decreased likelihood to feed. The second study aimed to assess the avoidance behavioural response of marine fish in their natural environment to pile-driving noise playback by use of a baited remote underwater video (BRUV) system coupled with a loudspeaker. Playback of pile-driving noise had a significant effect on the number of pelagic fish species surrounding the BRUV, indicating an avoidance effect. However, playback did not have a significant effect on the number of benthic fish species or species richness. Both these studies demonstrate that pile-driving noise causes behavioural changes in marine species, which could have potential fitness costs. Thus, exploration into ways of mitigating noise impacts when undertaking pile-driving activities in the ocean should be further explored.
Abstract.
2018
Yarlett RT, Perry CT, Wilson RW, Philpot KE (2018). Constraining species-size class variability in rates of parrotfish bioerosion on Maldivian coral reefs: implications for regional-scale bioerosion estimates.
Marine Ecology Progress Series,
590, 155-169.
Abstract:
Constraining species-size class variability in rates of parrotfish bioerosion on Maldivian coral reefs: implications for regional-scale bioerosion estimates
Parrotfish are important bioeroders on coral reefs, and thus influence reef carbonate budgets and generate large volumes of carbonate sand that contribute to local beach and reef island maintenance. However, despite the importance of this process, there is a paucity of data with which variations in bioerosion rates as a function of species, feeding modes, and body size of parrotfish can be constrained. There is, in addition, limited knowledge regarding how resultant rates may vary within and between reef-building regions. Here, direct estimates of parrotfish bioerosion rates were quantified across different size classes of 6 common species of Maldivian parrotfish. These species comprise both ‘scraper’ and ‘excavator’ taxa, and our data indicate marked variations in mean bioerosion rates among these species. We also note that all species exhibited an apparent bimodal feeding cycle, with peaks in the late morning and early afternoon. Highest bioerosion rates were found in the ‘excavator’ Chlorurus strongylocephalus (~460 kg ind.-1 yr-1), nearly 130 times greater than rates calculated for comparably sized (>45 cm) ‘scraper’ species. Our data provide metrics that can be used in conjunction with parrotfish biomass or density data to improve estimates of parrotfish bioerosion on central Indian Ocean reefs, a region of high parrotfish density, but from which only limited metrics exist. We emphasise the importance of obtaining sub-regional scale process data to better inform estimates of reef bioerosion, especially to support attempts to model the impacts of fishing pressure, which commonly results in removal of high-rate bioeroding taxa.
Abstract.
Yarlett RT, Perry CT, Wilson RW, Philpot KE (2018). Dataset for Yarlett et al. (2018) "Constraining species-size class variability in rates of parrotfish bioerosion on Maldivian coral reefs: implications for regional-scale bioerosion estimates" published in MEPS.
Porteus CS, Hubbard PC, Uren Webster TM, van Aerle R, Canário AVM, Santos EM, Wilson RW (2018). Near-future CO<inf>2</inf> levels impair the olfactory system of a marine fish.
Nature Climate Change,
8(8), 737-743.
Abstract:
Near-future CO2 levels impair the olfactory system of a marine fish
Survival of marine fishes that are exposed to elevated near-future CO2 levels is threatened by their altered responses to sensory cues. Here we demonstrate a physiological and molecular mechanism in the olfactory system that helps to explain altered behaviour under elevated CO2. We combine electrophysiology measurements and transcriptomics with behavioural experiments to investigate how elevated CO2 affects the olfactory system of European sea bass (Dicentrarchus labrax). When exposed to elevated CO2 (approximately 1,000 µatm), fish must be up to 42% closer to an odour source for detection, compared with current CO2 levels (around 400 µatm), decreasing their chances of detecting food or predators. Compromised olfaction correlated with the suppression of the transcription of genes involved in synaptic strength, cell excitability and wiring of the olfactory system in response to sustained exposure to elevated CO2 levels. Our findings complement the previously proposed impairment of γ-aminobutyric acid receptors, and indicate that both the olfactory system and central brain function are compromised by elevated CO2 levels.
Abstract.
2017
Ellis RP, Davison W, Queirós AM, Kroeker KJ, Calosi P, Dupont S, Spicer JI, Wilson RW, Widdicombe S, Urbina MA, et al (2017). Does sex really matter? Explaining intraspecies variation in ocean acidification responses.
Biol Lett,
13(2).
Abstract:
Does sex really matter? Explaining intraspecies variation in ocean acidification responses.
Ocean acidification (OA) poses a major threat to marine ecosystems globally, having significant ecological and economic importance. The number and complexity of experiments examining the effects of OA has substantially increased over the past decade, in an attempt to address multi-stressor interactions and long-term responses in an increasing range of aquatic organisms. However, differences in the response of males and females to elevated pCO2 have been investigated in fewer than 4% of studies to date, often being precluded by the difficulty of determining sex non-destructively, particularly in early life stages. Here we highlight that sex can significantly impact organism responses to OA, differentially affecting physiology, reproduction, biochemistry and ultimately survival. What is more, these impacts do not always conform to ecological theory based on differential resource allocation towards reproduction, which would predict females to be more sensitive to OA owing to the higher production cost of eggs compared with sperm. Therefore, non-sex-specific studies may overlook subtle but ecologically significant differences in the responses of males and females to OA, with consequences for forecasting the fate of natural populations in a near-future ocean.
Abstract.
Author URL.
Mangan S, Urbina MA, Findlay HS, Wilson RW, Lewis C (2017). Fluctuating seawater pH/pCO2 regimes are more energetically expensive than static pH/pCO2 levels in the mussel Mytilus edulis.
Proc Biol Sci,
284(1865).
Abstract:
Fluctuating seawater pH/pCO2 regimes are more energetically expensive than static pH/pCO2 levels in the mussel Mytilus edulis.
Ocean acidification (OA) studies typically use stable open-ocean pH or CO2 values. However, species living within dynamic coastal environments can naturally experience wide fluctuations in abiotic factors, suggesting their responses to stable pH conditions may not be reflective of either present or near-future conditions. Here we investigate the physiological responses of the mussel Mytilus edulis to variable seawater pH conditions over short- (6 h) and medium-term (2 weeks) exposures under both current and near-future OA scenarios. Mussel haemolymph pH closely mirrored that of seawater pH over short-term changes of 1 pH unit with acidosis or recovery accordingly, highlighting a limited capacity for acid-base regulation. After 2 weeks, mussels under variable pH conditions had significantly higher metabolic rates, antioxidant enzyme activities and lipid peroxidation than those exposed to static pH under both current and near-future OA scenarios. Static near-future pH conditions induced significant acid-base disturbances and lipid peroxidation compared with the static present-day conditions but did not affect the metabolic rate. These results clearly demonstrate that living in naturally variable environments is energetically more expensive than living in static seawater conditions, which has consequences for how we extrapolate future OA responses in coastal species.
Abstract.
Author URL.
Ellis RP, Urbina MA, Wilson RW (2017). Lessons from two high CO2 worlds - future oceans and intensive aquaculture.
Glob Chang Biol,
23(6), 2141-2148.
Abstract:
Lessons from two high CO2 worlds - future oceans and intensive aquaculture.
Exponentially rising CO2 (currently ~400 μatm) is driving climate change and causing acidification of both marine and freshwater environments. Physiologists have long known that CO2 directly affects acid-base and ion regulation, respiratory function and aerobic performance in aquatic animals. More recently, many studies have demonstrated that elevated CO2 projected for end of this century (e.g. 800-1000 μatm) can also impact physiology, and have substantial effects on behaviours linked to sensory stimuli (smell, hearing and vision) both having negative implications for fitness and survival. In contrast, the aquaculture industry was farming aquatic animals at CO2 levels that far exceed end-of-century climate change projections (sometimes >10 000 μatm) long before the term 'ocean acidification' was coined, with limited detrimental effects reported. It is therefore vital to understand the reasons behind this apparent discrepancy. Potential explanations include 1) the use of 'control' CO2 levels in aquaculture studies that go beyond 2100 projections in an ocean acidification context; 2) the relatively benign environment in aquaculture (abundant food, disease protection, absence of predators) compared to the wild; 3) aquaculture species having been chosen due to their natural tolerance to the intensive conditions, including CO2 levels; or 4) the breeding of species within intensive aquaculture having further selected traits that confer tolerance to elevated CO2. We highlight this issue and outline the insights that climate change and aquaculture science can offer for both marine and freshwater settings. Integrating these two fields will stimulate discussion on the direction of future cross-disciplinary research. In doing so, this article aimed to optimize future research efforts and elucidate effective mitigation strategies for managing the negative impacts of elevated CO2 on future aquatic ecosystems and the sustainability of fish and shellfish aquaculture.
Abstract.
Author URL.
Roberts CM, O'Leary BC, McCauley DJ, Cury PM, Duarte CM, Lubchenco J, Pauly D, Sáenz-Arroyo A, Sumaila UR, Wilson RW, et al (2017). Marine reserves can mitigate and promote adaptation to climate change.
Proc Natl Acad Sci U S A,
114(24), 6167-6175.
Abstract:
Marine reserves can mitigate and promote adaptation to climate change.
Strong decreases in greenhouse gas emissions are required to meet the reduction trajectory resolved within the 2015 Paris Agreement. However, even these decreases will not avert serious stress and damage to life on Earth, and additional steps are needed to boost the resilience of ecosystems, safeguard their wildlife, and protect their capacity to supply vital goods and services. We discuss how well-managed marine reserves may help marine ecosystems and people adapt to five prominent impacts of climate change: acidification, sea-level rise, intensification of storms, shifts in species distribution, and decreased productivity and oxygen availability, as well as their cumulative effects. We explore the role of managed ecosystems in mitigating climate change by promoting carbon sequestration and storage and by buffering against uncertainty in management, environmental fluctuations, directional change, and extreme events. We highlight both strengths and limitations and conclude that marine reserves are a viable low-tech, cost-effective adaptation strategy that would yield multiple cobenefits from local to global scales, improving the outlook for the environment and people into the future.
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Author URL.
2016
Rogers NJ, Urbina MA, Reardon EE, McKenzie DJ, Wilson RW (2016). A new analysis of hypoxia tolerance in fishes using a database of critical oxygen level (P crit).
Conserv Physiol,
4(1).
Abstract:
A new analysis of hypoxia tolerance in fishes using a database of critical oxygen level (P crit).
Hypoxia is a common occurrence in aquatic habitats, and it is becoming an increasingly frequent and widespread environmental perturbation, primarily as the result of anthropogenic nutrient enrichment and climate change. An in-depth understanding of the hypoxia tolerance of fishes, and how this varies among individuals and species, is required to make accurate predictions of future ecological impacts and to provide better information for conservation and fisheries management. The critical oxygen level (P crit) has been widely used as a quantifiable trait of hypoxia tolerance. It is defined as the oxygen level below which the animal can no longer maintain a stable rate of oxygen uptake (oxyregulate) and uptake becomes dependent on ambient oxygen availability (the animal transitions to oxyconforming). A comprehensive database of P crit values, comprising 331 measurements from 96 published studies, covering 151 fish species from 58 families, provides the most extensive and up-to-date analysis of hypoxia tolerance in teleosts. Methodologies for determining P crit are critically examined to evaluate its usefulness as an indicator of hypoxia tolerance in fishes. Various abiotic and biotic factors that interact with hypoxia are analysed for their effect on P crit, including temperature, CO2, acidification, toxic metals and feeding. Salinity, temperature, body mass and routine metabolic rate were strongly correlated with P crit; 20% of variation in the P crit data set was explained by these four variables. An important methodological issue not previously considered is the inconsistent increase in partial pressure of CO2 within a closed respirometer during the measurement of P crit. Modelling suggests that the final partial pressure of CO2 reached can vary from 650 to 3500
µatm depending on the ambient pH and salinity, with potentially major effects on blood acid-base balance and P crit itself. This database will form part of a widely accessible repository of physiological trait data that will serve as a resource to facilitate future studies of fish ecology, conservation and management.
Abstract.
Author URL.
McKenzie DJ, Axelsson M, Chabot D, Claireaux G, Cooke SJ, Corner RA, De Boeck G, Domenici P, Guerreiro PM, Hamer B, et al (2016). Conservation physiology of marine fishes: state of the art and prospects for policy.
Conserv Physiol,
4(1).
Abstract:
Conservation physiology of marine fishes: state of the art and prospects for policy.
The state of the art of research on the environmental physiology of marine fishes is reviewed from the perspective of how it can contribute to conservation of biodiversity and fishery resources. A major constraint to application of physiological knowledge for conservation of marine fishes is the limited knowledge base; international collaboration is needed to study the environmental physiology of a wider range of species. Multifactorial field and laboratory studies on biomarkers hold promise to relate ecophysiology directly to habitat quality and population status. The 'Fry paradigm' could have broad applications for conservation physiology research if it provides a universal mechanism to link physiological function with ecological performance and population dynamics of fishes, through effects of abiotic conditions on aerobic metabolic scope. The available data indicate, however, that the paradigm is not universal, so further research is required on a wide diversity of species. Fish physiologists should interact closely with researchers developing ecological models, in order to investigate how integrating physiological information improves confidence in projecting effects of global change; for example, with mechanistic models that define habitat suitability based upon potential for aerobic scope or outputs of a dynamic energy budget. One major challenge to upscaling from physiology of individuals to the level of species and communities is incorporating intraspecific variation, which could be a crucial component of species' resilience to global change. Understanding what fishes do in the wild is also a challenge, but techniques of biotelemetry and biologging are providing novel information towards effective conservation. Overall, fish physiologists must strive to render research outputs more applicable to management and decision-making. There are various potential avenues for information flow, in the shorter term directly through biomarker studies and in the longer term by collaborating with modellers and fishery biologists.
Abstract.
Author URL.
Middlemiss KL, Urbina MA, Wilson RW (2016). Effects of seawater alkalinity on calcium and acid-base regulation in juvenile European lobster (Homarus gammarus) during a moult cycle.
Comp Biochem Physiol a Mol Integr Physiol,
193, 22-28.
Abstract:
Effects of seawater alkalinity on calcium and acid-base regulation in juvenile European lobster (Homarus gammarus) during a moult cycle.
Fluxes of NH4(+) (acid) and HCO3(-) (base), and whole body calcium content were measured in European lobster (Homarus gammarus) during intermoult (megalopae stage), and during the first 24h for postmoult juveniles under control (~2000 μeq/L) and low seawater alkalinity (~830 μeq/L). Immediately after moulting, animals lost 45% of the total body calcium via the shed exoskeleton (exuvia), and only 11% was retained in the uncalcified body. At 24h postmoult, exoskeleton calcium increased to ~46% of the intermoult stage. Ammonia excretion was not affected by seawater alkalinity. After moulting, bicarbonate excretion was immediately reversed from excretion to uptake (~4-6 fold higher rates than intermoult) over the whole 24h postmoult period, peaking at 3-6h. These data suggest that exoskeleton calcification is not completed by 24h postmoult. Low seawater alkalinity reduced postmoult bicarbonate uptake by 29% on average. Net acid-base flux (equivalent to net base uptake) followed the same pattern as HCO3(-) fluxes, and was 22% lower in low alkalinity seawater over the whole 24h postmoult period. The common occurrence of low alkalinity in intensive aquaculture systems may slow postmoult calcification in juvenile H. gammarus, increasing the risk of mortalities through cannibalism.
Abstract.
Author URL.
Whittamore JM, Genz J, Grosell M, Wilson RW (2016). Measuring intestinal fluid transport in vitro: Gravimetric method versus non-absorbable marker.
Comp Biochem Physiol a Mol Integr Physiol,
194, 27-36.
Abstract:
Measuring intestinal fluid transport in vitro: Gravimetric method versus non-absorbable marker.
The gut sac is a long-standing, widely used in vitro preparation for studying solute and water transport, and calculation of these fluxes requires an accurate assessment of volume. This is commonly determined gravimetrically by measuring the change in mass over time. While convenient this likely under-estimates actual net water flux (Jv) due to tissue edema. We evaluated whether the popular in vivo volume marker [(14)C]-PEG 4000, offers a more representative measure of Jvin vitro. We directly compared these two methods in five teleost species (toadfish, flounder, rainbow trout, killifish and tilapia). Net fluid absorption by the toadfish intestine based on PEG was significantly higher, by almost 4-fold, compared to gravimetric measurements, compatible with the latter under-estimating Jv. Despite this, PEG proved inconsistent for all of the other species frequently resulting in calculation of net secretion, in contrast to absorption seen gravimetrically. Such poor parallelism could not be explained by the absorption of [(14)C]-PEG (typically
Abstract.
Author URL.
Eaton L, Sloman KA, Wilson RW, Gill AB, Harborne AR (2016). Non-consumptive effects of native and invasive predators on juvenile Caribbean parrotfish.
Environmental Biology of Fishes,
99(5), 499-508.
Abstract:
Non-consumptive effects of native and invasive predators on juvenile Caribbean parrotfish
Non-consumptive effects of predators can have important impacts on aquatic food webs, but there are few data on how predators change the behaviour of Caribbean reef fishes. Such changes may include behavioural responses to the invasive predatory lionfish (Pterois volitans/P. miles). This study used an aquarium experiment to examine the behaviour of herbivorous parrotfish (Scarus iseri) in the absence of other fish (control), with a non-piscivore present, and with a predatory threat from a native grouper or lionfish. Treatments were repeated with and without additional parrotfish shelters to examine the potential effects of degraded reefs (loss of refuges). Using video, parrotfish behaviours (sheltering, swimming in open areas, foraging, aggressive conspecific interactions, bite rates, and shoaling behaviour) were recorded for groups of four parrotfish. Compared to the control, the average number of parrotfish hiding was reduced by 65 % and foraging shoals were 10 % larger when threatened by grouper, likely as a specific response to an ambush predator. When exposed to lionfish, parrotfish reduced their bite rates by 50 %, possibly to be more vigilant of this predator’s unique stalking behaviour. The absence of additional shelter had limited effects although parrotfish formed 10 % larger shoals when swimming in open water, potentially as a defensive behaviour because of a perceived lack of refuges. The reduction in parrotfish bite rates caused by lionfish may have important demographic consequences. Furthermore, parrotfishes are important grazers of macroalgae, and these behavioural changes may exacerbate the direct effects of lionfish predation and potentially affect reef benthic dynamics.
Abstract.
Lewis C, Ellis RP, Vernon E, Elliot K, Newbatt S, Wilson RW (2016). Ocean acidification increases copper toxicity differentially in two key marine invertebrates with distinct acid-base responses.
Sci Rep,
6Abstract:
Ocean acidification increases copper toxicity differentially in two key marine invertebrates with distinct acid-base responses.
Ocean acidification (OA) is expected to indirectly impact biota living in contaminated coastal environments by altering the bioavailability and potentially toxicity of many pH-sensitive metals. Here, we show that OA (pH 7.71; pCO2 1480 μatm) significantly increases the toxicity responses to a global coastal contaminant (copper ~0.1 μM) in two keystone benthic species; mussels (Mytilus edulis) and purple sea urchins (Paracentrotus lividus). Mussels showed an extracellular acidosis in response to OA and copper individually which was enhanced during combined exposure. In contrast, urchins maintained extracellular fluid pH under OA by accumulating bicarbonate but exhibited a slight alkalosis in response to copper either alone or with OA. Importantly, copper-induced damage to DNA and lipids was significantly greater under OA compared to control conditions (pH 8.14; pCO2 470 μatm) for both species. However, this increase in DNA-damage was four times lower in urchins than mussels, suggesting that internal acid-base regulation in urchins may substantially moderate the magnitude of this OA-induced copper toxicity effect. Thus, changes in metal toxicity under OA may not purely be driven by metal speciation in seawater and may be far more diverse than either single-stressor or single-species studies indicate. This has important implications for future environmental management strategies.
Abstract.
Author URL.
2015
Middlemiss KL, Daniels CL, Urbina MA, Wilson RW (2015). Combined effects of UV irradiation, ozonation, and the probiotic Bacillus spp. on growth, survival, and general fitness in European lobster (Homarus gammarus).
Aquaculture,
444, 99-107.
Abstract:
Combined effects of UV irradiation, ozonation, and the probiotic Bacillus spp. on growth, survival, and general fitness in European lobster (Homarus gammarus)
Bacterial pathogens are a leading cause of disease in hatchery aquaculture systems and preventative methods such as use of probiotics as feed supplements and water additives are well documented. However, comparisons between the effectiveness of using probiotic water additives over traditional biocontrol methods are less understood. This study assessed the combined effects of ultraviolet (UV) irradiation, O3 (ozone) and Bacillus spp. as a water additive (probiotic), in the culture of European lobster (Homarus gammarus) in a semi-closed recirculation system. Larvae were categorised as zoea stages I-III, megalopa (stage IV) and juvenile (stage V) onwards. Stage I larvae were assigned to one of six treatment groups consisting of 1) O3, 2) probiotic, 3) probiotic+O3, 4) probiotic+O3+ UV, 5) O3+UV, or 6) probiotic+UV, for 18days. During stages I-V, growth was measured on 1, 6, 11, 18, 24, and 31dph (days post hatch), and survival was measured on 1, 18, 24 and 31dph. Bacterial counts of pathogenic Vibrio spp. in culture water were measured at 1, 4, 9, 14, and 18dph. Lobsters were also exposed to a physiological fitness test (low salinity challenge) at stage IV, 7days post treatment. Results showed that O3 is comparatively more beneficial than probiotic with increased LWG (live weight gain) in the O3 treatment over probiotic between stage IV and V (>5mg). Survival rates were ~10% higher in the O3 treatment group than probiotic treatment group on day 18, then ~5% and ~4% higher on days 24 and 31. Lobster biomass on day 18 was ~60% higher in the O3 treatment than probiotic treatment and 116% higher on day 31. Total Vibrio spp. present in the O3 treatment was 0.05% of the total in the probiotic treated culture water (day 18). Results between UV treatment groups showed significantly lower numbers of Vibrio spp. present in probiotic+O3+UV culture water 4dph than O3+UV (~10 fold higher) or UV+probiotic (~15 fold higher) and by day 18 probiotic+O3+UV was significantly higher than O3+UV (~8 fold higher). Osmoregulatory challenge test resulted in no significant differences in physiological fitness between any treatment groups. The present study shows the effectiveness of O3 in aquaculture facilities for control of pathogens in the rearing of European lobster over either a probiotic water additive (at 3.75×107CFUsL-1) or UV irradiation.
Abstract.
Daniels CL, Wills B, Ruiz-Perez M, Miles E, Wilson RW, Boothroyd D (2015). Development of sea based container culture for rearing European lobster (Homarus gammarus) around South West England.
Aquaculture,
448, 186-195.
Abstract:
Development of sea based container culture for rearing European lobster (Homarus gammarus) around South West England
This three year field investigation consisted of three discrete experiments, examining six potential sites for rearing the European lobster (Homarus gammarus) around the Cornish coast (U.K.). Sea-based container culture (SBCC) systems were deployed, varying site, year, depth, shelter and pre-fouling, to test effects on growth and survival of juvenile H. gammarus. Site and depth were examined between May-August 2011 at two sites off the South coast. One estuarine (River Fal: RF) and one sea-based (St. Austell Bay: SA) site were assessed with containers suspended at either 2 or 8 m depth. Greatest survival was found at the SA site (56%) compared to RF (25%), with the greatest growth (specific growth rate: SGR 3%, live weight gain: LWG 0.4. g and carapace length gain: CLG 4.5 mm) also achieved at SA. Depth did not affect juvenile development. Between May and August 2012, one estuarine (Fowey: F) and two sea-based (SA and St. Mawes: SM) sites on the south coast were selected to assess the effect of site and shelter. SM showed the highest survival (93%). Growth and survival were not affected by the presence of a shelter. From August to December 2013, three sites off the north and south coasts were selected to assess the effect of site, depth, pre-fouling and feed availability. Sea-based (Port Quin Bay: PQ, Wave Hub: WH and SA) sites were assessed, with containers submerged at either 3 or 10 m above the sea bed (PQ 7-14 m, WH 42-49 m depth at chart datum). Survival did not significantly differ between sites (61-86%), but growth at the PQ site (LWG 0.7 g; carapace length gain: CLG 6.1 mm) was significantly greater than at all other sites (LWG 0.3-0.4 g; CLG 2.5-3.6 mm). Depth did not affect juvenile development. Pre-fouling reduced growth at all sites. Feed availability varied between sites with PQ showing the greatest taxonomical units. Variations between years were also shown between 2011 and 2013 at the SA site. SBCC systems show potential for culturing H. gammarus juveniles compared to hatchery controls (survival ≤ 46%), acting as a transition step between hatchery rearing and release for stocking purposes. The importance of site selection and between year variations is highlighted as important factors to consider for larger scale assessment of aquaculture potential. Statement of relevance: This work presents the culmination of three discrete studies between 2011 and 2013 that investigated the use of sea based container culture (SBCC) systems for rearing European lobster (H. gammarus) juveniles at various sites around South West England. This is a relatively novel field and the first study of its kind to consider sites around the South West of England and also to quantitatively assess potential feed species. The main findings of this work identify the importance of site selection, deployment and container structure. With an ever increasing demand for protein, there needs to be efforts to relieve pressure on natural fishing stocks. This study not only highlights the potential for SBCC to provide improved stock enhancement processes but also discusses the potential for aquaculture of this currently unexploited species.Juvenile culture is one of the bottlenecks for the development of lobster culture due to high unit cost of production, high mortality rates due to cannibalism within intensive culture systems and long development times, and as such we feel that this work is extremely timely and relevant. This manuscript will not only contribute to the understanding of how SBCC systems can be employed, but also adds to our understanding of the requirements of the species. Therefore, this work is of significant interest to those involved in the culture of lobsters and marine animals generally.
Abstract.
Middlemiss KL, Urbina MA, Wilson RW (2015). Microbial proliferation on gill structures of juvenile European lobster (Homarus gammarus) during a moult cycle.
Helgoland Marine Research,
69(4), 401-410.
Abstract:
Microbial proliferation on gill structures of juvenile European lobster (Homarus gammarus) during a moult cycle
The morphology of gill-cleaning structures is not well described in European lobster (Homarus gammarus). Furthermore, the magnitude and time scale of microbial proliferation on gill structures is unknown to date. Scanning electron microscopy was used to investigate development of setae in zoea, megalopa and juvenile stages (I–V). Microbes were classified and quantified on gill structures throughout a moult cycle from megalopa (stage IV) to juvenile (stage V). Epipodial serrulate setae, consisting of a naked proximal setal shaft with the distal portion possessing scale-like outgrowths (setules), occur only after zoea stage III. After moulting to megalopa (stage IV), gill structures were completely clean and no microbes were visible on days 1 or 5 postmoult. Microbial proliferation was first evident on day 10 postmoult, with a significant 16-fold increase from day 10 to 15. Rod-shaped bacteria were initially predominant (by day 10); however, by day 15 the microbial community was dominated by cocci-shaped bacteria. This research provides new insights into the morphology of gill-grooming structures, the timing of their development, and the magnitude, timescale and characteristics of gill microbial proliferation during a moult cycle. To some degree, the exponential growth of epibionts on gills found during a moult cycle will likely impair respiratory (gas exchange) and ion regulatory function, yet further research is needed to evaluate the physiological effects of the exponential bacterial proliferation documented here.
Abstract.
2014
Schmitz OJ, Raymond PA, Estes JA, Kurz WA, Holtgrieve GW, Ritchie ME, Schindler DE, Spivak AC, Wilson RW, Bradford MA, et al (2014). Animating the Carbon Cycle.
ECOSYSTEMS,
17(2), 344-359.
Author URL.
Wilson RW (2014).
Chapter 3.6 Fish. IUCN, Switzerland, Gland. 13 pages.
Author URL.
Pope EC, Ellis RP, Scolamacchia M, Scolding JWS, Keay A, Chingombe P, Shields RJ, Wilcox R, Speirs DC, Wilson RW, et al (2014). European sea bass, Dicentrarchus labrax, in a changing ocean.
Biogeosciences,
11(9), 2519-2530.
Abstract:
European sea bass, Dicentrarchus labrax, in a changing ocean
Ocean acidification, caused by rising concentrations of carbon dioxide (CO2), is widely considered to be a major global threat to marine ecosystems. To investigate the potential effects of ocean acidification on the early life stages of a commercially important fish species, European sea bass (Dicentrarchus labrax), 12 000 larvae were incubated from hatch through metamorphosis under a matrix of two temperatures (17 and 19 °C) and two seawater pCO2 levels (ambient and 1,000 μatm) and sampled regularly for 42 days. Calculated daily mortality was significantly affected by both temperature and pCO2, with both increased temperature and elevated pCO2 associated with lower daily mortality and a significant interaction between these two factors. There was no significant pCO2 effect noted on larval morphology during this period but larvae raised at 19 °C possessed significantly larger eyes and lower carbon:nitrogen ratios at the end of the study compared to those raised under 17 °C. Similarly, when the incubation was continued to post-metamorphic (juvenile) animals (day 67-69), fish raised under a combination of 19 °C and 1000 μatm pCO2 were significantly heavier. However, juvenile D. labrax raised under this combination of 19 °C and 1000 μatm pCO2 also exhibited lower aerobic scopes than those incubated at 19 °C and ambient pCO2. Most studies investigating the effects of near-future oceanic conditions on the early life stages of marine fish have used incubations of relatively short durations and suggested that these animals are resilient to ocean acidification. Whilst the increased survival and growth observed in this study supports this view, we conclude that more work is required to investigate whether the differences in juvenile physiology observed in this study manifest as negative impacts in adult fish. copyright © Author(s) 2014.
Abstract.
Wilson RW (2014). Fish. In Laffoley D, Baxter J, Thevenon F, Oliver J (Eds.)
The Significance and Management of Natural Carbon Stores in the Open Ocean, Switzerland: IUCN, 81-94.
Author URL.
Cooper CA, Regan MD, Brauner CJ, De Bastos ESR, Wilson RW (2014). Osmoregulatory bicarbonate secretion exploits H+-sensitive haemoglobins to autoregulate intestinal O2 delivery in euryhaline teleosts.
Journal of Comparative Physiology BAbstract:
Osmoregulatory bicarbonate secretion exploits H+-sensitive haemoglobins to autoregulate intestinal O2 delivery in euryhaline teleosts
Abstract Marine teleost fish secrete bicarbonate (HCO 3 - ) into the intestine to aid osmoregulation and limit Ca 2+. uptake by carbonate precipitation. Intestinal HCO 3 -. secretion is associated with an equimolar transport of protons (H + ) into the blood, both being proportional to environmental salinity. We hypothesized that the H + -sensitive haemoglobin (Hb) system of seawater teleosts could be exploited via the Bohr and/or Root effects (reduced Hb-O 2. affinity and/or capacity with decreasing pH) to improve O 2. delivery to intestinal cells during high metabolic demand associated with osmoregulation. To test this, we characterized H +. equilibria and gas exchange properties of European flounder (Platichthys flesus)haemoglobin and constructed a model incorporating these values, intestinal blood flow rates and arterial-venous acidification at three different environmental salinities (33, 60 and 90). The model suggested red blood cell pH (pH i ) during passage through intestinal capillaries could be reduced by 0.14-0.33 units (depending on external salinity) which is sufficient to activate the Bohr effect (Bohr coefficient of -0.63), and perhaps even the Root effect, and enhance tissue O 2. delivery by up to 42 % without changing blood flow. In vivo measurements of intestinal venous blood pH were not possible in flounder but were in seawater-acclimated rainbow trout which confirmed a blood acidification of no less than 0.2 units (equivalent to -0.12 for pH i ). When using trout-specific values for the model variables, predicted values were consistent with measured in vivo values, further supporting themodel. Thus this system is an elegant example of autoregulation: as the need for costly osmoregulatory processes (including HCO 3 -. secretion) increases at higher environmental salinity, so does the enhancement of O 2. delivery to the intestine via a localized acidosis and the Bohr (and possibly Root) effect. © 2014 the Author(s).
Abstract.
Cooper CA, Regan MD, Brauner CJ, De Bastos ESR, Wilson RW (2014). Osmoregulatory bicarbonate secretion exploits H<sup>+</sup>-sensitive haemoglobins to autoregulate intestinal O<inf>2</inf> delivery in euryhaline teleosts.
Journal of Comparative Physiology B: Biochemical, Systemic, and Environmental Physiology,
184(7), 865-876.
Abstract:
Osmoregulatory bicarbonate secretion exploits H+-sensitive haemoglobins to autoregulate intestinal O2 delivery in euryhaline teleosts
Marine teleost fish secrete bicarbonate (HCO3−) into the intestine to aid osmoregulation and limit Ca2+ uptake by carbonate precipitation. Intestinal HCO3− secretion is associated with an equimolar transport of protons (H+) into the blood, both being proportional to environmental salinity. We hypothesized that the H+-sensitive haemoglobin (Hb) system of seawater teleosts could be exploited via the Bohr and/or Root effects (reduced Hb-O2 affinity and/or capacity with decreasing pH) to improve O2 delivery to intestinal cells during high metabolic demand associated with osmoregulation. To test this, we characterized H+ equilibria and gas exchange properties of European flounder (Platichthys flesus)haemoglobin and constructed a model incorporating these values, intestinal blood flow rates and arterial–venous acidification at three different environmental salinities (33, 60 and 90). The model suggested red blood cell pH (pHi) during passage through intestinal capillaries could be reduced by 0.14–0.33 units (depending on external salinity) which is sufficient to activate the Bohr effect (Bohr coefficient of −0.63), and perhaps even the Root effect, and enhance tissue O2 delivery by up to 42 % without changing blood flow. In vivo measurements of intestinal venous blood pH were not possible in flounder but were in seawater-acclimated rainbow trout which confirmed a blood acidification of no less than 0.2 units (equivalent to −0.12 for pHi). When using trout-specific values for the model variables, predicted values were consistent with measured in vivo values, further supporting themodel. Thus this system is an elegant example of autoregulation: as the need for costly osmoregulatory processes (including HCO3− secretion) increases at higher environmental salinity, so does the enhancement of O2 delivery to the intestine via a localized acidosis and the Bohr (and possibly Root) effect.
Abstract.
Salter MA, Perry CT, Wilson RW (2014). Size fraction analysis of fish-derived carbonates in shallow sub-tropical marine environments and a potentially unrecognised origin for peloidal carbonates.
Sedimentary Geology,
314, 17-30.
Abstract:
Size fraction analysis of fish-derived carbonates in shallow sub-tropical marine environments and a potentially unrecognised origin for peloidal carbonates
Marine bony fish are now known as primary producers of calcium carbonate. Furthermore, within the shallow sub-tropical platform settings of the Bahamas, this production process has been shown to occur at rates relevant to carbonate sediment production budgets. Fish excrete these carbonates as loosely aggregated pellets which, post-excretion, exhibit a range of distinctive crystal morphologies and have mineralogies ranging from low (0-4mol% MgCO3) to high (4-40mol% MgCO3) Mg-calcites, aragonite and amorphous carbonate phases. Here we provide the first quantitative assessment of the size fractions of the carbonates produced by a range of tropical fish species, and document the extent of post-excretion carbonate pellet break down under a range of physical agitation conditions. Specifically, we document the morphologies and size fractions of: i) intact pellets at the point of excretion; ii) intact pellets after agitation in seawater; and iii) the particles released from pellets post-disaggregation. Results indicate that fish-derived pellets initially fall within the very fine to very coarse sand fractions. Exposure to conditions of moderate seawater agitation for 30days results in significant pellet diminution; 66% of initial pellet mass being released as individual particles, whilst 34% is retained as partially intact pellets that are smaller (fine sand-grade) and more rounded than initial pellets. In contrast, pellets exposed to very gently agitated conditions for up to 200days show little change. Where pellet disaggregation does occur, particles are commonly released as individual clay- and silt-grade crystals. However, some morphotypes (e.g. polycrystalline spheres) can be intergrown and are released as strongly cohesive particle clusters falling within the coarse silt to fine sand fractions. Only very vigorous agitation may disaggregate such particles, resulting in the release of their component clay-grade crystals. We conclude that fish-derived carbonates may thus contribute not only to the mud-fraction of marine carbonates, but also to the fine sand fraction as intergrown particles, and to the fine to coarse sand fractions as intact and partially intact pellets. These experimental data indicate that hydrodynamic regimes local to sites of excretion will influence the generation of carbonates with different size fraction ranges. Rapid pellet disaggregation is more likely in high energy settings, hypothesised to result in redistribution of liberated mud-grade particles to lower energy platform-top settings and/or off-platform. In contrast, pellets excreted in lower energy settings are more likely to be preserved intact, and are thus proposed as a previously unrecognised source of pelletal and peloidal carbonate sediments. •Break-up of carbonate pellets produced by marine bony fish is investigated. •Pellets can remain intact and may contribute to sedimentary pellets and peloids. •Rapid pellet break-up releases component particles in agitated settings. •Particle size ranges from clay to fine sand grade: different depositional fates. •Relevant to surface sediments in shallow sub-tropical marine provinces.
Abstract.
2013
Schmitz OJ, Raymond PA, Estes JA, Kurz WA, Holtgrieve GW, Ritchie ME, Schindler DE, Spivak AC, Wilson RW, Bradford MA, et al (2013). Animating the Carbon Cycle. Ecosystems, 1-16.
2012
Wilkes L, Owen SF, Readman GD, Sloman KA, Wilson RW (2012). Does structural enrichment for toxicology studies improve zebrafish welfare?. Applied Animal Behaviour Science
Wilkes L, Owen SF, Readman GD, Sloman KA, Wilson RW (2012). Does structural enrichment for toxicology studies improve zebrafish welfare?.
Applied Animal Behaviour Science,
139(1-2), 143-150.
Abstract:
Does structural enrichment for toxicology studies improve zebrafish welfare?
Enrichment of the environment for captive animals is aimed at producing beneficial effects on the behaviour and physiology of relevant species, and is commonly used to reduce harmful social behaviours and stereotypies. However, little work has been undertaken to develop enrichment strategies for fish, in particular those used in regulatory toxicology where strict criteria regarding holding conditions and experimental design can make implementing such techniques problematic. Here, we studied the effect of vertical rod structures, designed to increase environmental complexity and provide refuge, on several commonly cited anxiety-related behaviours and whole-body levels of the stress hormone cortisol in juvenile zebrafish measured over a 1-week period. Activity levels and shoaling density showed no response to tank structures and fish did not spend a significantly greater or lesser amount of time in areas of tanks containing glass rods. Aggression remained high during days 1-5 in tanks containing glass structures before falling to a lower level by day 7. In control tanks, this lower level was reached 2 days earlier, by day 5, suggesting that the glass structures may have slowed the rate of establishment of dominant/subordinate relationships. Overall, whole-body cortisol levels of fish were comparable to those reported in unstressed zebrafish in other studies. Levels were significantly higher in both treatments after 24. h than on subsequent days, most likely due to the handling stress of the initial transfer to experimental tanks. However, cortisol levels did not vary significantly between control and structured tanks at any point during the study. These results indicate that the addition of glass rod structures as hypothesised enrichment did not result in a measurable improvement in welfare. © 2012 Elsevier B.V.
Abstract.
Salter MA, Perry CT, Wilson RW (2012). Production of mud-grade carbonates by marine fish: Crystalline products and their sedimentary significance. Sedimentology
Salter MA, Perry C, Wilson RW (2012). Production of mud-grade carbonates by marine fish: crystalline products and their sedimentary significance. Sedimentolology, in press
2011
Al-Jandal NJ, Wilson RW (2011). A comparison of osmoregulatory responses in plasma and tissues of rainbow trout (Oncorhynchus mykiss) following acute salinity challenges.
Comp Biochem Physiol a Mol Integr Physiol,
159(2), 175-181.
Abstract:
A comparison of osmoregulatory responses in plasma and tissues of rainbow trout (Oncorhynchus mykiss) following acute salinity challenges.
Euryhaline teleosts regulate their internal osmotic and ionic status across a wide range of external salinities. Studies often rely on measurements on plasma when osmoregulatory status is perturbed, whereas tissue measurements are used for small fish with limited blood volume. However, a direct comparison is lacking for plasma and various tissues. In the present study the relationships between plasma, white muscle and carcass were examined for a range of osmoregulatory variables in rainbow trout (Oncorhynchus mykiss) following challenge with an acute (24 h) transfer from freshwater to a hyper-osmotic salinity of either 25 or 35. Significant increases in plasma osmolality, [Na+], [Cl⁻], [Ca²+], and [Mg²+] were observed when salinity was increased, but plasma [K+] was unaffected. The water content of both tissues showed reciprocal changes to plasma osmolality. The carcass content of all ions measured showed a significant increase at the highest ambient salinity. In white muscle, Na+, K+ and Mg²+ showed significant increases with external salinity, but Cl⁻ and Ca²+ were unaffected. Measurements from both tissues can provide reliable surrogates for most of the plasma osmoregulatory variables except Cl⁻ and Ca²+ when using white muscle tissue. In the case of internal regulation of K+ both tissues provide sensitive and quantitatively similar indicators of environmental salinity disturbance, whereas plasma does not.
Abstract.
Author URL.
Wilson RW, Reardon EE, Perry CT (2011). A fishy tale: a missing part of the inorganic ocean carbon cycle.
The Biochemist(June), 30-34.
Author URL.
Perry CT, Salter MA, Harborne AR, Crowley SF, Jelks HL, Wilson RW (2011). Fish as major carbonate mud producers and missing components of the tropical carbonate factory.
Proc Natl Acad Sci U S A,
108(10), 3865-3869.
Abstract:
Fish as major carbonate mud producers and missing components of the tropical carbonate factory.
Carbonate mud is a major constituent of recent marine carbonate sediments and of ancient limestones, which contain unique records of changes in ocean chemistry and climate shifts in the geological past. However, the origin of carbonate mud is controversial and often problematic to resolve. Here we show that tropical marine fish produce and excrete various forms of precipitated (nonskeletal) calcium carbonate from their guts ("low" and "high" Mg-calcite and aragonite), but that very fine-grained (mostly < 2 μm) high Mg-calcite crystallites (i.e. > 4 mole % MgCO(3)) are their dominant excretory product. Crystallites from fish are morphologically diverse and species-specific, but all are unique relative to previously known biogenic and abiotic sources of carbonate within open marine systems. Using site specific fish biomass and carbonate excretion rate data we estimate that fish produce ∼6.1 × 10(6) kg CaCO(3)/year across the Bahamian archipelago, all as mud-grade (the < 63 μm fraction) carbonate and thus as a potential sediment constituent. Estimated contributions from fish to total carbonate mud production average ∼14% overall, and exceed 70% in specific habitats. Critically, we also document the widespread presence of these distinctive fish-derived carbonates in the finest sediment fractions from all habitat types in the Bahamas, demonstrating that these carbonates have direct relevance to contemporary carbonate sediment budgets. Fish thus represent a hitherto unrecognized but significant source of fine-grained carbonate sediment, the discovery of which has direct application to the conceptual ideas of how marine carbonate factories function both today and in the past.
Abstract.
Author URL.
Wilson RW (2011). Role of the gut.
,
2, 1419-1428.
Abstract:
Role of the gut
The gut is well known for processing all the ionic products from the digestion of food. However, the majority of our knowledge of the ionic and osmoregulatory roles of the gut in fish is based on nonfeeding animals and, in particular, the central role the gut plays in processing imbibed seawater as part of the hypoosmoregulatory strategy of marine teleosts. For seawater fish that drink large volumes of salty water, we have a detailed understanding of several mechanisms, including the molecular identity of various membrane transporters and cellular enzymes that drive osmotic water absorption by the gut: (1) NaCl co-transport; (2) HCO3? secretion via apical Cl?/HCO3? exchange; (3) apical and basolateral roles of H+ secretion to improve local osmotic gradients; and (4) the alkaline precipitation of calcium carbonate that chemically generates osmotic gradients to maximize water absorption. Although we may appreciate the details of these driving forces, surprisingly there is still little definitive evidence for the precise route and mechanism of water transport, despite the discovery of aquaporin water channels over 20 years ago and the common assumption of their direct role in transmembrane absorption. In freshwater fish, the gut has very little potential for any role in osmotic or ionic regulation in the nonfeeding state due to 10-50-fold lower drinking rates and >100-fold lower NaCl concentrations in ingested fluid. During feeding, recent studies reveal a surprising role for the stomach in absorption of ions, but overall the gut is a site of net water loss. The gut is also a strong candidate for involvement in acid-base regulation given it is potential for very high rates of gastric HCl and pancreatic HCO3? secretion in most fish associated with digestion, and intestinal HCO3? secretion in marine teleosts associated with osmoregulation. However, this potential role has only been explored recently, revealing a substantial post-prandial alkaline tide as a direct result of gastric acid secretion, and a role for the intestine in sequestering excess HCO3? base during extracellular alkalosis. © 2011 Elsevier Inc. All rights reserved.
Abstract.
Al-Jandal NJ, Whittamore JM, Santos EM, Wilson RW (2011). The influence of 17β-estradiol on intestinal calcium carbonate precipitation and osmoregulation in seawater-acclimated rainbow trout (Oncorhynchus mykiss).
J Exp Biol,
214(Pt 16), 2791-2798.
Abstract:
The influence of 17β-estradiol on intestinal calcium carbonate precipitation and osmoregulation in seawater-acclimated rainbow trout (Oncorhynchus mykiss).
The intestine of marine teleosts produces carbonate precipitates from ingested calcium as part of their osmoregulatory strategy in seawater. The potential for estrogens to control the production of intestinal calcium carbonate and so influence osmoregulation was investigated in seawater-acclimated rainbow trout following intraperitoneal implantation of 17β-estradiol (E2) at two doses (0.1 and 10 μg E2 g(-1)). Levels of plasma vitellogenin provided an indicator of estrogenic effect, increasing significantly by three and four orders of magnitude at the low and high doses, respectively. Plasma osmolality and muscle water content were unaffected, whereas E2-treated fish maintained lower plasma [Na(+)] and [Cl(-)]. Plasma [Ca(2+)] and [Mg(2+)] and muscle [Ca(2+)] increased with vitellogenin induction, whereas the intestinal excretion of calcium carbonate was reduced. This suggests that elevated levels of circulating E2 may enhance Ca(2+) uptake via the gut and simultaneously reduce CaCO(3) formation, which normally limits intestinal availability of Ca(2+). Increasing E2 caused an elevation of [Na(+)] and [Cl(-)] and a reduction of [HCO(3(-))] in intestinal fluid. We speculate that E2 may influence a number of intestinal ion transport processes that ultimately may influence water absorption: (1) reduced NaCl cotransport, (2) reduced Cl(-) uptake via Cl(-)/HCO(3(-)) exchange and (3) reduced precipitation of Ca(2+) and Mg(2+) carbonates. Despite these effects on intestinal ion and water transport, overall osmoregulatory status was not compromised in E2-treated fish, suggesting the possibility of compensation by other organs.
Abstract.
Author URL.
2010
Cooper CA, Whittamore JM, Wilson RW (2010). Ca2+-driven intestinal HCO(3)(-) secretion and CaCO3 precipitation in the European flounder in vivo: influences on acid-base regulation and blood gas transport.
Am J Physiol Regul Integr Comp Physiol,
298(4), R870-R876.
Abstract:
Ca2+-driven intestinal HCO(3)(-) secretion and CaCO3 precipitation in the European flounder in vivo: influences on acid-base regulation and blood gas transport.
Marine teleost fish continuously ingest seawater to prevent dehydration and their intestines absorb fluid by mechanisms linked to three separate driving forces: 1) cotransport of NaCl from the gut fluid; 2) bicarbonate (HCO(3)(-)) secretion and Cl(-) absorption via Cl(-)/HCO(3)(-) exchange fueled by metabolic CO(2); and 3) alkaline precipitation of Ca(2+) as insoluble CaCO(3), which aids H(2)O absorption). The latter two processes involve high rates of epithelial HCO(3)(-) secretion stimulated by intestinal Ca(2+) and can drive a major portion of water absorption. At higher salinities and ambient Ca(2+) concentrations the osmoregulatory role of intestinal HCO(3)(-) secretion is amplified, but this has repercussions for other physiological processes, in particular, respiratory gas transport (as it is fueled by metabolic CO(2)) and acid-base regulation (as intestinal cells must export H(+) into the blood to balance apical HCO(3)(-) secretion). The flounder intestine was perfused in vivo with salines containing 10, 40, or 90 mM Ca(2+). Increasing the luminal Ca(2+) concentration caused a large elevation in intestinal HCO(3)(-) production and excretion. Additionally, blood pH decreased (-0.13 pH units) and plasma partial pressure of CO(2) (Pco(2)) levels were elevated (+1.16 mmHg) at the highest Ca perfusate level after 3 days of perfusion. Increasing the perfusate [Ca(2+)] also produced proportional increases in net acid excretion via the gills. When the net intestinal flux of all ions across the intestine was calculated, there was a greater absorption of anions than cations. This missing cation flux was assumed to be protons, which vary with an almost 1:1 relationship with net acid excretion via the gill. This study illustrates the intimate link between intestinal HCO(3)(-) production and osmoregulation with acid-base balance and respiratory gas exchange and the specific controlling role of ingested Ca(2+) independent of any other ion or overall osmolality in marine teleost fish.
Abstract.
Author URL.
Whittamore JM, Cooper CA, Wilson RW (2010). HCO (3)(-) secretion and CaCO3 precipitation play major roles in intestinal water absorption in marine teleost fish in vivo.
Am J Physiol Regul Integr Comp Physiol,
298(4), R877-R886.
Abstract:
HCO (3)(-) secretion and CaCO3 precipitation play major roles in intestinal water absorption in marine teleost fish in vivo.
The intestine of marine teleosts must effectively absorb fluid from ingested seawater to avoid dehydration. This fluid transport has been almost exclusively characterized as driven by NaCl absorption. However, an additional feature of the osmoregulatory role of the intestine is substantial net HCO(3)(-) secretion. This is suggested to drive additional fluid absorption directly (via Cl(-)/HCO(3)(-) exchange) and indirectly by precipitating ingested Ca(2+) as CaCO(3), thus creating the osmotic gradient for additional fluid absorption. The present study tested this hypothesis by perfusing the intestine of the European flounder in vivo with varying [Ca(2+)]: 10 (control), 40, and 90 mM. Fractional fluid absorption increased from 47% (control) to 73% (90 mM Ca(2+)), where almost all secreted HCO(3)(-) was excreted as CaCO(3). This additional fluid absorption could not be explained by NaCl cotransport. Instead, a significant positive relationship between Na(+)-independent fluid absorption and total HCO(3)(-) secretion was consistent with the predicted roles for anion exchange and CaCO(3) precipitation. Further analysis suggested that Na(+)-independent fluid absorption could be accounted for by net Cl(-) and H(+) absorption (from Cl(-)/HCO(3)(-) exchange and CO(2) hydration, respectively). There was no evidence to suggest that CaCO(3) alone was responsible for driving fluid absorption. However, by preventing the accumulation of luminal Ca(2+) it played a vital role by dynamically maintaining a favorable osmotic gradient all along the intestine, which permits substantially higher rates of solute-linked fluid absorption. To overcome the resulting hyperosmotic and highly acidic absorbate, it is proposed that plasma HCO(3)(-) buffers the absorbed H(+) (from HCO(3)(-) production), and consequently reduces the osmolarity of the absorbed fluid entering the body.
Abstract.
Author URL.
Saxby A, Adams L, Snellgrove D, Wilson RW, Sloman KA (2010). The effect of group size on the behaviour and welfare of four fish species commonly kept in home aquaria.
Applied Animal Behaviour Science,
125(3-4), 195-205.
Abstract:
The effect of group size on the behaviour and welfare of four fish species commonly kept in home aquaria
Previous research into fish welfare has focussed particularly on commercially important aquaculture species. However, with over 350 million fishes traded annually within the ornamental fish industry, surprisingly little consideration has been given to the welfare of fish kept in home aquaria. Here, the welfare of four commonly kept species of ornamental fish (neon tetras, white cloud mountain minnows, angelfish and tiger barbs) was investigated in relation to group size. Behaviours including darting, aggression, shoaling and latency to feed were found to vary with group size in a species-specific manner. Neon tetras and white cloud mountain minnows displayed reduced aggression and darting and spent more time shoaling in larger groups. Behavioural patterns were more variable in angelfish and tiger barbs although larger group sizes resulted in increased shoaling. Principal components analysis of the behaviour scores obtained indicated improved welfare in larger groups of neon tetras, white cloud mountain minnows and tiger barbs with no clear link between welfare and group size in angelfish. In conclusion, although the effect of group size on the behaviour of ornamental fish species is species-specific, combination of behavioural parameters within a principal components analysis allows group sizes that promote improved welfare to be identified. © 2010 Elsevier B.V.
Abstract.
Saxby A, Adams L, Snellgrove D, Wilson RW, Sloman KA (2010). The effect of group size on the behaviour and welfare of four fish species commonly kept in home aquaria. Applied Animal Behaviour Science
2009
Wilson RW, Millero FJ, Taylor JR, Walsh PJ, Christensen V, Jennings S, Grosell M (2009). Contribution of Fish to the Marine Inorganic Carbon Cycle.
SCIENCE,
323(5912), 359-362.
Author URL.
Jennings S, Wilson RW (2009). Fishing impacts on the marine inorganic carbon cycle.
Journal of Applied Ecology,
46(5), 976-982.
Abstract:
Fishing impacts on the marine inorganic carbon cycle
Teleost fish excrete precipitated carbonate and make significant contributions to the marine inorganic carbon cycle at regional and global scales. As total carbonate production is linked to fish size and abundance, fishing is predicted to affect carbonate production by modifying fish abundance and size-structure. We draw on concepts from physiology, metabolic ecology, life history theory, population dynamics and community ecology to develop, validate and apply analytical tools to assess fishing impacts on carbonate production. Outputs suggest that population and community carbonate production fall rapidly at lower rates of fishing than those used as management targets for sustainable yield. Theoretical predictions are corroborated by estimated trends in carbonate production by a herring population and a coral reef fish community subject to fishing. Our analytical results build on widely applicable relationships between life history parameters and metabolic rates, and can be generalized to most fished ecosystems. Synthesis and applications. If the maintenance of chemical processes as well as biological process were adopted as a management objective for fisheries then the methods we have developed can be applied to assess the effects of fishing on carbonate production and to advise on acceptable rates of fishing. Maintenance of this ecosystem service would require lower rates of fishing mortality than those recommended to achieve sustainable yield. © 2009 British Ecological Society.
Abstract.
Ghosh J, Wilson RW, Kudoh T (2009). Normal development of the tomato clownfish
Amphiprion frenatus: live imaging and in situ
hybridization analyses of mesodermal and
neurectodermal development.
J. Fish Biol.,
75, 2287-2298.
Abstract:
Normal development of the tomato clownfish
Amphiprion frenatus: live imaging and in situ
hybridization analyses of mesodermal and
neurectodermal development
The normal embryonic development of the tomato clownfish Amphiprion frenatus was analysed
using live imaging and by in situ hybridization for detection of mesodermal and neurectodermal
development. Both morphology of live embryos and tissue-specific staining revealed significant
differences in the gross developmental programme of A. frenatus compared with better-known
teleost fish models, in particular, initiation of somitogenesis before complete epiboly, initiation of
narrowing of the neurectoderm (neurulation) before somitogenesis, relatively early pigmentation
of melanophores at the 10–15 somite stage and a distinctive pattern of melanophore distribution.
These results suggest evolutionary adaptability of the teleost developmental programme. The ease
of obtaining eggs, in vitro culture of the embryo, in situ staining analyses and these reported
characteristics make A. frenatus a potentially important model marine fish species for studying
embryonic development, physiology, ecology and evolution.
Abstract.
Saxby AL, Snellgrove D, Wilson RW, Sloman KA (2009). Welfare Implications of stocking density on two fish species (Paracheirodon innesi and Tanichthys albonubes) kept in home aquaria.
Author URL.
2008
Sloman KA, Baker D, Winberg S, Wilson RW (2008). Are there physiological correlates of dominance in natural trout populations?.
Animal Behaviour,
76(4), 1279-1287.
Abstract:
Are there physiological correlates of dominance in natural trout populations?
Competition over limited resources can lead to serious injury and may be minimized by the formation of social hierarchies. However, there are often physiological consequences associated with social status which can affect both dominant and subordinate animals. In salmonid fish, at least under laboratory conditions, physiological costs are mainly associated with subordinance. The structure of hierarchies formed among salmonids in the laboratory is likely to be different from those formed in complex natural environments, and yet little is known about the physiological consequences of dominance in the field. We tested the hypothesis that there are specific physiological correlates associated with specific social behaviours among natural populations of juvenile salmonid fish by observing brown trout, Salmo trutta, in small streams. Fish were tagged and their behaviour observed by video recording over several weeks at three sites along Devonport Leat (Devon, U.K.). Although diet and tissue metal concentrations differed between sites, the behaviour of the fish at the three sites was very similar. At the end of the observation period, we sampled fish for parameters including specific growth rate, plasma cortisol and osmolality, brain monoamines and gut contents. There was no relationship between social status and growth rates but, contrary to laboratory predictions, dominant fish had higher plasma cortisol. We conclude that physiological correlates of dominance do exist among these natural fish populations but they may differ to those found in the laboratory. Further research is now required to test a wider range of physiologies in the field. © 2008 the Association for the Study of Animal Behaviour.
Abstract.
Scott DM, Rabineau J, Wilson RW, Hodgson DJ, Brown JA (2008). Can pikeperch colonise new freshwater systems via estuaries? Evidence from behavioural salinity tests.
Marine and Freshwater Research,
59(8), 694-702.
Abstract:
Can pikeperch colonise new freshwater systems via estuaries? Evidence from behavioural salinity tests
Pikeperch (Sander lucioperca) are non-native in the United Kingdom. It is important to understand how environmental factors, such as salinity, influence the behaviour and activity of introduced fish species to identify their dispersal potential. Previous studies have shown that pikeperch, traditionally recognised as a freshwater fish, can tolerate brackish waters and demonstrate physiological acclimation. However, their behavioural responses to brackish waters are unknown. The aim of the present study was therefore to investigate the activity and swimming behaviour of pikeperch obtained from freshwater canals in southern England. In the laboratory, fish were exposed to a 12-h simulated tidal cycle and a 12-day stepped salinity challenge where salinity was increased by 4 every 2 days, up to a salinity of 20. In both regimes, fish showed increased swimming activity in response to increasing salinity, which may represent an avoidance response. The most dramatic changes, including vertical movements, occurred at salinities above ∼16. At these higher salinities, head shaking and coughing behaviours were also observed, suggesting significant stress and respiratory impairment. However, during the simulated tidal cycle, normal behaviour was rapidly restored once salinity was reduced. The results of this study may have implications in understanding the dispersal of non-native fish in the wild. © CSIRO 2008.
Abstract.
Mélin, F. Blanchard, J.L. Forster, R.M. (2008). Global-scale predictions of community and ecosystem properties from simple ecological theory. Proceedings of the Royal Society B, 275, 1375-1383.
2007
Scott DM, Wilson RW, Brown JA (2007). Can sunbleak Leucaspius delineatus or topmouth gudgeon Pseudorasbora parva disperse through saline waters?.
Journal of Fish Biology,
71(SUPPL. D), 70-86.
Abstract:
Can sunbleak Leucaspius delineatus or topmouth gudgeon Pseudorasbora parva disperse through saline waters?
In order to determine the potential for the invasive fishes sunbleak Leucaspius delineatus and topmouth gudgeon Pseudorasbora parva to disperse through saline waters their behaviour and physiology were investigated during exposure to salinities of 10.0 and 12.5. Increased salinity caused an increase in whole body cortisol in both species, but sunbleak and topmouth gudgeon showed very different metabolic and behavioural responses to the salinity stress. Sunbleak displayed increased swimming activity in brackish water, which may be important for dispersal through saline waters in the wild, although there were increased metabolic costs associated with this behaviour. Conversely, topmouth gudgeon showed a reduction in both swimming activity and metabolic rate in brackish waters. A pronounced depression in food intake (70-80%) was shown by both species during the salinity exposures. Both sunbleak and topmouth gudgeon, however, showed a full recovery of food intake within 24 h following return to fresh water. Despite the fact that exposure to saline waters is stressful, and affects both physiology and behaviour, rapid recovery of appetite after return to fresh water suggests that short-term use of brackish waters is a feasible dispersal route for sunbleak and topmouth gudgeon in the wild. © 2007 the Fisheries Society of the British Isles.
Abstract.
Scott, D.M. Wilson, R.W. (2007). Do estuaries act as saline-bridges to allow invasion of new freshwater systems by non-indigenous fish species?. In Gherardi F (Ed) Biological Invaders in Inland Waters: Profiles, Distribution and Threats, Springer.
Wilson, R.W. (2007). Post-prandial alkaline tide in freshwater teleost fish: Effects of meal anticipation on physiological recovery from acid-base and ion regulatory disturbances of feeding.<em>Proofs of this manuscript are available from Chris Cooper C.A.Cooper@ex.ac.uk</em>. Journal of Experimental Biology
Taylor JR, Whittamore JM, Wilson RW, Grosell M (2007). Postprandial acid-base balance and ion regulation in freshwater and seawater-acclimated European flounder, Platichthys flesus.
J Comp Physiol B,
177(6), 597-608.
Abstract:
Postprandial acid-base balance and ion regulation in freshwater and seawater-acclimated European flounder, Platichthys flesus.
The effects of feeding on both acid-base and ion exchange with the environment, and internal acid-base and ion balance, in freshwater and seawater-acclimated flounder were investigated. Following voluntary feeding on a meal of 2.5-5% body mass and subsequent gastric acid secretion, no systemic alkaline tide or respiratory compensation was observed in either group. Ammonia efflux rates more than doubled from 489 +/- 35 and 555 +/- 64 mumol kg(-1) h(-1) under control conditions to 1,228 +/- 127 and 1,300 +/- 154 mumol kg(-1) h(-1) post-feeding in freshwater and seawater-acclimated fish, respectively. Based on predictions of gastric acid secreted during digestion, we calculated net postprandial internal base gains (i.e. HCO (3) (-) secreted from gastric parietal cells into the blood) of 3.4 mmol kg(-1) in seawater and 9.1 mmol kg(-1 )in freshwater-acclimated flounder. However, net fluxes of ammonia, titratable alkalinity, Na(+) and Cl(-) indicated that branchial Cl(-)/HCO (3) (-) and Na(+)/H(+) exchange played minimal roles in counteracting these predicted base gains and cannot explain the absence of alkaline tide. Instead, intestinal Cl(-)/HCO (3) (-) exchange appears to be enhanced after feeding in both freshwater and seawater flounder. This implicates the intestine rather than the gills as a potential route of postprandial base excretion in fish, to compensate for gastric acid secretion.
Abstract.
Author URL.
Whittamore, J.M. Wilson, R.W. Grosell, M. (2007). Postprandial acid-base balance in freshwater and seawater-acclimated European flounder. Integrative & Comparative Biology, 45(6), 1081-1081.
Brown, J.A. Wilson, R.W. (2007). The osmoregulatory ability of the European invasive species sunbleak Leucaspius delineatus and topmouth gudgeon Pseudorasbora parva at elevated salinities, and their likely dispersal via brackish waters. Journal of Fish Biology, 70, 1606-1614.
Wilson, R.W. (2007). Three species of fish from an eutrophic, seasonally alkaline lake are not more tolerant to acute high pH exposure in the laboratory. Journal of Fish Biology, 70, 551-566.
2005
Gonzalez, R.J. Wilson, R.W. (2005). A pharmacological examination of Na+ and Cl- transport in two species of freshwater fish. Physiological and Biochemical Zoology, 78(2), 259-272.
Wilson, R.W. (2005). Anthropogenic effects on behavioural physiology in fish. In Sloman, K, Wilson, RW, Balshine, S (Eds.) Behaviour - Interactions with Fish Physiology, Academic Press, 413-468.
Grosell M, Wood CM, Wilson RW, Bury NR, Hogstrand C, Rankin C, Jensen FB (2005). Bicarbonate secretion plays a role in chloride and water absorption of the European flounder intestine.
American Journal of Physiology - Regulatory Integrative and Comparative Physiology,
288(4 57-4).
Abstract:
Bicarbonate secretion plays a role in chloride and water absorption of the European flounder intestine
Experiments performed on isolated intestinal segments from the marine teleost fish, the European flounder (Platichthys flesus), revealed that the intestinal epithelium is capable of secondary active HCO3- secretion in the order of 0.2-0.3 HCO3- against an apparent electrochemical gradient. The HCO3- secretion occurs via anion exchange, is dependent on mucosal Cl-, results in very high mucosal HCO3- concentrations, and contributes significantly to Cl- and fluid absorption. This present study was conducted under in vivo-like conditions, with mucosal saline resembling intestinal fluids in vivo. These conditions result in a transepithelial potential of -16.2 mV (serosal side negative), which is very different from the -2.2 mV observed under symmetrical conditions. Under these conditions, we found a significant part of the HCO3- secretion is fueled by endogenous epithelial CO2 hydration mediated by carbonic anhydrase because acetazolamide (10-4 M) was found to inhibit HCO 3- secretion and removal of serosal CO2 was found not to influence HCO3- secretion. Reversal of the epithelial electrochemical gradient for CP (removal of serosal Cl-) and elevation of serosal HCO3- resulted in enhanced HCO3- secretion and enhanced Cl- and fluid absorption. Cl- absorption via an anion exchange system appears to partly drive fluid absorption across the intestine in the absence of net Na + absorption. Copyright © 2005 the American Physiological Society.
Abstract.
Wilson RW, Wilson JM, Grosell M (2005). Erratum: Intestinal bicarbonate secretion by marine teleost fish - Why and how? (Biochimica et Biophysica Acta, Biomembranes (2002) 1566 (182-193) PII: S0005-2736(02)00600-4 and DOI: 10.1016/S0005-2736(02)00600-4). Biochimica et Biophysica Acta - Biomembranes, 1712(2).
Wilson RW, Wilson JM, Grosell M (2005). Intestinal bicarbonate secretion by marine teleost fish - Why and how? (vol 1566, pg 182, 2002).
BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES,
1712(2), 222-222.
Author URL.
Lucas, M.L. Wilson, R.W. (2005). The effect of chronic exposure to high pH on the sodium balance, nitrogen excretion and behaviour of fish from a freshwater eutrophic lake: a laboratory and field study. Aquatic Toxicology, 73(1), 31-43.
Scott DM, Lucas MC, Wilson RW (2005). The effect of high pH on ion balance, nitrogen excretion and behaviour in freshwater fish from an eutrophic lake: a laboratory and field study.
Aquat Toxicol,
73(1), 31-43.
Abstract:
The effect of high pH on ion balance, nitrogen excretion and behaviour in freshwater fish from an eutrophic lake: a laboratory and field study.
Slapton Ley is a freshwater hyper-eutrophic lake of two basins connected by a narrow channel. One part of the lake experiences summer blooms of cyanobacteria and poor water quality, including elevated water pH (maximum pH recorded=10.54), the other part is shaded by reed beds, and remains clear and neutral. This study used laboratory and field physiological measurements together with radio-tracking to investigate the potential impacts of alkaline pH on the physiology and behaviour of fish from Slapton Ley. Exposure of perch (Perca fluviatilis) from Slapton Ley to pH 9.50 water in the laboratory caused an immediate inhibition of sodium uptake and ammonia excretion to 34 and 32% of control levels, respectively. Net sodium balance recovered by day 3 of exposure whereas ammonia excretion only partially recovered to 60-70% of the control value from 8 h onwards. Urea excretion did not increase as a result of high pH exposure. Fish from the alkaline part of the lake (pH 9.90) had almost three-fold greater plasma ammonia compared to fish from neutral waters, indicating a pronounced disruption of ammonia excretion in the field. There was no significant disturbance to plasma sodium, chloride or total protein in fish sampled from the alkaline water of Slapton Ley. The radio-tracking provided no evidence of adult perch and pike (Esox lucius) trying to seek refuge from the alkaline conditions, despite having access to adjacent parts of the lake with neutral pH. It seems likely that there are advantages (e.g. better foraging, less predation) of withstanding the high pH conditions that outweigh the benefit of moving into more pH neutral parts of the lake.
Abstract.
Author URL.
Gilmour KM, Wilson RW, Sloman KA (2005). The integration of behaviour into comparative physiology.
Physiological and Biochemical Zoology,
78(5), 609-678.
Abstract:
The integration of behaviour into comparative physiology
Comparative physiology has traditionally focused on the physiological responses of animals to their physicochemical environment. In recent years, awareness has increased among physiologists of the potential for behavioural factors, such as the social environment of the animal, to affect physiological condition and responses. This recognition has led to an emerging trend within the field toward using multidisciplinary approaches that incorporate both behavioural and physiological techniques. Research areas in which the integrated study of behaviour and physiology has been particularly fruitful include the physiology of the social environment, sensory physiology and behaviour, and physiological constraints on behavioural ecology. The manner in which incorporating behavioural considerations has informed the physiological data collected is discussed for each of these areas using specific examples. © 2005 by the University of Chicago. All rights reserved.
Abstract.
Gilmour KM, Wilson RW, Sloman KA (2005). The integration of behaviour into comparative physiology.
Abstract:
The integration of behaviour into comparative physiology.
Abstract.
Author URL.
2004
Wilson RW, Bury NR, Grosell M, Wood CM (2004). Bicarbonate secretion plays a role in chloride and water absorption of the European flounder intestine. American Journal of Physiology: Regulatory, Integrative and Comparative Physiology, 288(4), R936-R946.
Wilson, R.W. Wood, C.M. (2004). Environmental effects on ion regulation in tropical fish. In Val AL (Ed) Physiology of Tropical Fish, Academic Press, 397-442.
Wilson, R.W. Wood, C.M. (2004). Ion regulation in tropical fishes from ion-poor, acidic blackwaters. In Val AL (Ed) Physiology of Tropical Fish, Fish Physiology Vol. 21 - Academic Press pp. 397-442:.
2003
Wilson RW, Grosell M (2003). Intestinal bicarbonate secretion in marine teleost fish - source of bicarbonate, pH sensitivity, and consequences for whole animal acid-base and calcium homeostasis. Biochimica et Biophysica Acta (BBA) - Biomembranes, 1618(2), 163-174.
Matsuo, A. YO, R.W. Wilson, R.J. (2003). Protection by natural blackwater against disturbances in ion fluxes caused by low pH exposure in freshwater stingrays endemic to the Rio Negro. Physiological and Biochemical Zoology, 76, 12-27.
2002
Wood, C.M. Bury, N.R. Wilson, R.W. (2002). Binding and movement of Ag in the intestinal epithelium of a marine teleost fish, European flounder. Comparative Biochemistry and Physiology C-Toxicology & Pharmacology, 133, 125-135.
Wilson, R.W. Wood, C.M. Patrick, M.L. (2002). Diverse strategies for ion regulation in fish collected from the ion-poor, acidic Rio Negro. Physiological and Biochemical Zoology, 75, 37-47.
Wilson RW, Grosell M, Wilson JM (2002). Intestinal bicarbonate secretion by marine teleost fish - why and how?. Biochimica et Biophysica Acta (BBA) - Biomembranes, 1566(1-2), 182-193.
Ferreira, R.L. Gonzalez, R.J. Wood, C.M. (2002). Ion regulatory patterns of mosquito larvae collected from breeding sites in the Amazon rain forest. Physiological and Biochemical Zoology, 75, 215-222.
Matsuo, A.Y.O. Gonzalez, R.J. (2002). Mechanisms of ion transport in Potamotrygon, a stenohaline freshwater elasmobranch native to the ion-poor blackwaters of the Rio Negro. Journal of Experimental Biology, 205(19), 3039-3054.
Lecklin, T. Busk, M. Bury, N.R. (2002). Physiological impact of salinity at organism and red blood cell levels in the European flounder (P. flesus). Journal of Experimental Marine Biology and Ecology, 274, 159-174.
Jensen FB, Lecklin T, Busk M, Bury NR, Wilson RW, Wood CM, Grosell M (2002). Physiological impact of salinity increase at organism and red blood cell levels in the European flounder (Platichthys flesus).
Journal of Experimental Marine Biology and Ecology,
274(2), 159-174.
Abstract:
Physiological impact of salinity increase at organism and red blood cell levels in the European flounder (Platichthys flesus)
Blood respiratory, acid-base, and ionic changes in response to hyperosmotic shock were studied in vivo and in vitro in the European flounder. One primary aim was to evaluate regulatory changes in red blood cell (RBC) volume and its interrelationship with blood O2 transporting properties. An acute increase in the ambient salinity from 10 to 30 ppt caused small but significant increases in extracellular osmolality (
Abstract.
Gonzalez, R.J. Wood, C.M. Wilson, R.W. (2002). The characterization of ion regulation in Amazonian mosquito larvae: Evidence of phenotypic plasticity, population-based disparity, and novel mechanisms of ion uptake. Physiological and Biochemical Zoology, 75, 223-236.
2001
Wilson RW, Bury NR, Grosell M, Wood CM (2001). Intestinal iron uptake in the European flounder (Platichthys flesus). Journal of Experimental Biology, 204(21), 3779-3787.
Wilson, R.W. (2001). Patterns of ion regulation in acidophilic fish native to the ion-poor, acidic Rio Negro. Journal of Fish Biology, 58, 1680-1690.
2000
Allin CJ, Wilson RW (2000). Effects of pre-acclimation to aluminium on the physiology and swimming behaviour of juvenile rainbow trout (Oncorhynchus mykiss) during a pulsed exposure.
Aquat Toxicol,
51(2), 213-224.
Abstract:
Effects of pre-acclimation to aluminium on the physiology and swimming behaviour of juvenile rainbow trout (Oncorhynchus mykiss) during a pulsed exposure.
Anthropogenic acidification of the freshwater environment causes aluminium to be mobilised into the aquatic environment. When pH falls below 5.5, exposure to aluminium concentrations as low as 12.5 microg.l(-1) can cause serious physiological disturbances in freshwater fish. However, under constant laboratory exposures fish can acclimate and recover physiological status within 5-30 days. In reality, fish in the wild are likely to experience chronic sub-lethal exposure, with occasional elevations (pulses) to much higher levels. The experiment described here investigated the effects of an environmentally realistic, 4-day pulse exposure to a high level of aluminium (36 microg.l(-1)) in two groups of juvenile rainbow trout. One group was exposed to a lower level of aluminium (24 microg.l(-1)) for 16 days before and 10 days after the pulse ('aluminium-acclimated' fish). A second group was exposed to pH 5.2 alone for 16 days before and 10 days after the pulse ('aluminium-naïve' fish). A third group exposed to pH 5.2 alone for 30 days (no aluminium added) acted as controls. Triplicate groups of 24 juvenile rainbow trout (2.3-16.7 g) were randomly allocated to one of these three treatments. Swimming behaviour was monitored throughout and samples were taken on days 14, 20, 22, 26 and 30 for assessment of physiological status. No treatment effects were recorded in the control group (pH 5.2 alone). Fish in the 'aluminium-acclimated' treatment became hypo-active upon initiation of the exposure to 24 microg.l(-1) aluminium, but recovered after just 4 days of this exposure. Subsequent challenge on day 16 with the 36 microg.l(-1) aluminium 'pulse' caused these fish to became hypo-active again, but they recovered normal swimming behaviour whilst still subject to the 4-day pulse. The 'aluminium-naïve' fish also became hypo-active during the pulse exposure (36 microg.l(-1) aluminium). However, they did not exhibit any recovery of swimming behaviour, either during the pulse, or even 6 days after the cessation of the pulse, despite a rapid depuration of gill aluminium load (within 2 days of the pulse finishing). Mortality was low in the aluminium-acclimated fish (4%) and significantly higher in the aluminium-naïve fish (26%). Haematological disturbances were most extreme in the aluminium-naïve fish and had not recovered to control levels 6 days after the end of the pulse. This study provides new evidence, using behavioural responses, that previous exposure to low levels of aluminium may be an important factor abating the impact of aluminium on fish in the natural environment.
Abstract.
Author URL.
1999
Allin CJ, Wilson RW (1999). Behavioural and metabolic effects of chronic exposure to sublethal aluminum in acidic soft water in juvenile rainbow trout (Oncorhynchus mykiss).
Canadian Journal of Fisheries and Aquatic Sciences,
56(4), 670-678.
Abstract:
Behavioural and metabolic effects of chronic exposure to sublethal aluminum in acidic soft water in juvenile rainbow trout (Oncorhynchus mykiss)
Triplicate groups of 15 softwater-acclimated juvenile rainbow trout (Oncorhynchus mykiss) were randomly allocated to one of three treatments: pH 6.5 with no aluminum, pH 5.2 with no aluminum, and pH 5.2 with 30 μg labile aluminum·L-1. The aluminum dose was sublethal and continued for 34 days. Treatment effects on swimming behaviour, metabolism, feeding, food conversion efficiency, and blood parameters were determined. Fish exposed to aluminum displayed hypoactivity that was statistically distinct from both control groups from day 1 onwards. Exposure to acid alone elicited no behavioural effects. There were no significant differences in metabolic rates between the treatment groups. Feeding rates of the fish exposed to aluminum became depressed, reaching a minimum on day 15, and gradually recovered thereafter, but never to the preexposure levels. Swimming behaviour was a more sensitive index of exposure to aluminum than feeding. Fish exposed to aluminum had significantly fewer red blood cells and lower haematocrit than the controls, indicating haemodilution. Aluminum is known to act as a respiratory toxicant, restricting aerobic scope. In addition, these data suggest that fish respond to aluminum exposure by reducing metabolically costly activities such as routine swimming behaviour to allow for the increased maintenance costs associated with acclimation and damage repair.
Abstract.
Wilson RW, Wood CM, Gonzalez RJ, Patrick ML, Bergman HL, Narahara A, Val AL (1999). Ion and acid-base balance in three species of Amazonian fish during gradual acidification of extremely soft water.
Physiol Biochem Zool,
72(3), 277-285.
Abstract:
Ion and acid-base balance in three species of Amazonian fish during gradual acidification of extremely soft water.
Sensitivity to acid water was assessed in three species of Amazonian fish that encounter naturally acidic blackwaters to differing degrees in the wild: tambaqui (Colossoma macropomum), matrincha (Brycon erythropterum), and tamoatá (Hoplosternum littorale), in decreasing order of occurrence in blackwater. Fish were exposed to a graded reduction in water pH, from pH 6 to 5 to 4 to 3.5, followed by return to pH 6. Fish were exposed to each new pH for 24 h. During these exposures, net transfers of ions (Na+, K+, Cl-, and Ca2+) and acid-base equivalents to and from the external water were used as physiological indicators of acid tolerance. Exposure to pH 5 had a minimal effect on net ion fluxes. Significant net losses of all ions (except Ca2+) were recorded in all three species during the first few hours of exposure to pH 4. However, ion balance was usually restored within 18 h at pH 4. Exposure to pH 3.5 caused even greater ion losses in all three species and proved to be acutely lethal to tamoatá. Matrincha sustained irreversible physiological damage at pH 3.5, as ion fluxes did not recover following return to pH 6 and there was some mortality. Tambaqui suffered the least ionoregulatory disturbances at pH 3.5 and was the only species to make a full recovery on return to pH 6. In all species, there was a tendency for ammonia excretion to increase at low water pH, but even at pH 3.5, there was no significant net uptake of acid from the water. Overall, there was a strong relationship between the magnitude of ionic disturbances and the lethality of exposure to low pH. The relative insensitivity of the ionoregulatory system of tambaqui to low pH indicates that this is a feature of fish native to blackwater systems rather than one that is common to all Amazon fish.
Abstract.
Author URL.
1998
Gonzalez RJ, Wood CM, Wilson RW, Patrick ML, Bergman HL, Narahara A, Val AL (1998). Effects of water pH and calcium concentration on ion balance in fish of the Rio Negro, Amazon.
Physiological Zoology,
71(1), 15-22.
Abstract:
Effects of water pH and calcium concentration on ion balance in fish of the Rio Negro, Amazon
We examined the effects of acute low-pH exposure on ion balance (Na+, Cl-, K+) in several species of fish captured from the Rio Negro, a dilute, acidic tributary of the Amazon. At pH 5.5 (untreated Rio Negro water), the four Rio Negro species tested (piranha preta, Serrasalmus rhombeus; piranha branca, Serrasalmus cf. holandi; aracu, Leporinus fasciatus; and pacu, Myleus sp.) were at or near ion balance; upon exposure to pH 3.5, while Na+ and Cl- loss rates became significant, they were relatively mild. In comparison, tambaqui (Colossoma macropomum), which were obtained from aquaculture and held and tested under the same conditions as the other fish, had loss rates seven times higher than all the Rio Negro species. At pH 3.0, rates of Na+ and Cl- loss for the Rio Negro fish increased three- to fivefold but were again much less than those observed in tambaqui. Raising water Ca2+ concentration from 10 μmol L-1 to 100 μmol L-1 during exposure to the same low pH's had no effect on rates of ion loss in the three species tested (piranha preta, piranha branca, aracu), which suggests that either they have such a high branchial affinity for Ca2+ that all sites are saturated at 10 μmol L-1 and additional Ca2+ had no effect, or that Ca2+ may not be involved in regulation of branchial ion permeability. For a final Rio Negro species, the cardinal tetra (Paracheirodon axelrodi), we monitored body Na+ concentration during 5 d of exposure to pH 6.0, 4.0, or 3.5. These pH's had no effect on body Na+ concentration. These data together suggest that exceptional acid tolerance is a general characteristic of fish that inhabit the dilute acidic Rio Negro and raise questions about the role of Ca2+ in regulation of branchial ion permeability in these fish.
Abstract.
Wilson RW, Wareing M, Kibble J, Green R (1998). Potassium permeability in the absence of fluid reabsorption in proximal tubule of the anesthetized rat.
American Journal of Physiology - Renal Physiology,
274(6 43-6).
Abstract:
Potassium permeability in the absence of fluid reabsorption in proximal tubule of the anesthetized rat
A luminal microperfusion technique was used to examine the K+ permeability of surface proximal convoluted tubules (PCT) in the kidney of anesthetized rats. Transtubular potassium concentration ([K+]) gradients were varied by altering the concentration of KCl in luminal perfusates, to which 32 mmol/l of the impermeant solute raffinose was also added to prevent net fluid reabsorption. The arithmetic mean transtubular [K+] gradient was highly predictive of net potassium flux, yielding an apparent K+ permeability of 31.9 ± 1.7 x 10-5 cm/s in the absence of fluid reabsorption. When compared using identical calculation techniques, we found this was not significantly different from the permeability derived in a previous study when fluid reabsorption was present [J. D. Kibble, M. Wareing, R. W. Wilson, and R. Green. Am. J. Physiol. 268 (Renal Fluid Electrolyte Physiol. 27): F778-F783, 1995]. We conclude that fluid reabsorption does not affect the apparent permeability of the proximal tubule to potassium. The apparent permeability to 86Rb, measured following its addition to luminal perfusates, was not significantly different from the value obtained for K+, suggesting that rubidium is a useful marker for net potassium movements in the PCT of the rat.
Abstract.
Wilson RW, Wareing M, Kibble J, Green R (1998). Potassium permeability in the absence of fluid reabsorption in proximal tubule of the anesthetized rat.
AMERICAN JOURNAL OF PHYSIOLOGY-RENAL PHYSIOLOGY,
274(6), F1109-F1112.
Author URL.
Wood CM, Wilson RW, Gonzalez RJ, Patrick ML, Bergman HL, Narahara A, Val AL (1998). Responses of an Amazonian teleost, the tambaqui (Colossoma macropomum), to low pH in extremely soft water.
Physiological Zoology,
71(6), 658-670.
Abstract:
Responses of an Amazonian teleost, the tambaqui (Colossoma macropomum), to low pH in extremely soft water
Our goal was to compare the internal physiological responses to acid challenge in an acidophilic tropical teleost endemic to dilute low-pH waters with those in nonacidophilic temperate species such as salmonids, which have been the subject of most previous investigations. The Amazonian tambaqui (Colossoma macropomum), which migrates between circumneutral water and dilute acidic 'blackwater' of the Rio Negro, was exposed to a graded low-pH and recovery regime in representative soft water (Na+ = 15, Cl- = 16, Ca2+ = 20 μmol L-1). Fish were fitted with arterial catheters for repetitive blood sampling. Water pH was altered from 6.5 (control) to 5.0, 4.0, 3.0, and back to 6.5 (recovery) on successive days. Some deaths occurred at pH 3.0. Throughout the regime, there were no disturbances of blood gases (O2 and CO2 tensions and contents) or lactate levels, and only very minor changes in acid-base status of plasma and red cells. However, erythrocytic guanylate and adenylate levels increased at pH's less than or equal to 5.0. Down to pH 4.0, plasma glucose, cortisol, and total ammonia levels remained constant, but all increased at pH 3.0, denoting a stress response. Plasma Na+ and Cl- levels declined and plasma protein concentration increased at pH 3.0, indicative of ionoregulatory and fluid volume disturbance, and neither recovered upon return to pH 6.5. Cortisol and ammonia elevations also persisted. Transepithelial potential changed progressively from highly negative values (inside) at pH 6.5 to highly positive values at pH 3.0; these alterations were fully reversible. Experimental elevations in water calcium levels drove the transepithelial potential positive at circumneutral pH, attenuated or prevented changes in transepithelial potential at low pH, and reduced Na+ and Cl- loss rates to the water during acute low-pH challenges. In general, tambaqui exhibited responses to low pH that were qualitatively similar but quantitatively more resistant than those previously documented in salmonids.
Abstract.
1997
Wilson RW, Wareing M, Green R (1997). The role of active transport in potassium reabsorption in the proximal convoluted tubule of the anaesthetized rat.
J Physiol,
500 ( Pt 1)(Pt 1), 155-164.
Abstract:
The role of active transport in potassium reabsorption in the proximal convoluted tubule of the anaesthetized rat.
1. We have previously assessed the contributions of diffusion and convection to net potassium reabsorption in the rat proximal convoluted tubule (PCT). The present study was conducted to evaluate the role of active transport in convective potassium reabsorption by measuring the transepithelial potassium reflection coefficient (sigmaK) in the presence and absence of cyanide in anaesthetized rats previously prepared for in vivo microperfusion. 2. Osmotic water permeability (Pf) was measured in double-perfused tubules (lumen and peritubular capillaries) by manipulating the applied transepithelial osmotic gradient between -30 and +40 mosmol (kg H2O)(-1) using raffinose added to or subtracted from luminal perfusates. Pf was unaffected by the presence of cyanide when the estimated dissipation of osmotic gradients along each tubule were taken into account. 3. The proportion of K+ (and Na+) convectively transported with water fluxes (i.e. sigmaK) was not affected by cyanide. In the absence of active transport and following correction for any diffusive component, sigmaK was 0.56 +/- 0.13, indicating substantial solvent drag which probably occurs via the paracellular pathway. 4. However, cyanide caused a reduction in net potassium flux over the entire range of fluid fluxes used in double-perfusion experiments. Subsequent single-perfusion experiments (tubule lumen only) using the specific K+-H+-ATPase inhibitor, SCH28080, failed to reveal any direct evidence for a primary active K+ transporting mechanism involved in K+ reabsorption in the PCT.
Abstract.
Author URL.
1996
Ishiguro H, Steward MC, Wilson RW, Case RM (1996). Bicarbonate secretion in interlobular ducts from guinea-pig pancreas.
Journal of Physiology,
495(1), 179-191.
Abstract:
Bicarbonate secretion in interlobular ducts from guinea-pig pancreas
1. The transport of HCO3- across the luminal membrane of pancreatic duct cells was studied by monitoring the luminal pH of isolated guinea-pig interlobular ducts after microinjection of an extracellular fluoroprobe, the dextran conjugate of 2'7'-bis(2-carboxyethyl)-5(6)-carboxyfluorescein (BCECF-dextran). Luminal Cl- concentration was also measured by microfluorometry following microinjection of the dextran conjugates of 6-methoxy-N-(4-aminoalkyl)quinolinium bromide (ABQ-dextran) and Cl-NERF (Cl-NERF-dextran). 2. When HCO3-/CO2 was admitted to the bath, a transient acidification of the duct lumen was observed, followed by a marked alkalinization. The latter was abolished when the luminal Cl- concentration was reduced to 25-35 mM by replacement with glucuronate and may therefore, be attributed to Cl--HCO3- exchange at the luminal membrane. 3. Secretin, forskolin and acetylcholine stimulated HCO3- secretion into the lumen even when the luminal Cl- concentration was reduced to approximately 7 mM. Furthermore, agonist-evoked HCO3- secretion was not inhibited by luminal glibenclamide, dihydro-4,4'-diisothiocyanostilbene-2,2'- disulphonic acid (H2DIDS) or 5-nitro-2-(3-phenylpropylamino)-benzoic acid (NPPB). These observations are not easily reconciled with HCO3- transport across the luminal membrane being mediated by Cl--HCO3- exchange in parallel with a Cl- conductance. 4. Agonist-stimulated HCO3- secretion was blocked by omitting Na+ from the bath but not by addition of N-methyl-N-isobutlamiloride (MIA) or bafilomycin A1. This supports our previous conclusion that HCO3- entry into duct cells from the extracellular fluid requires Na+ but is not dependent on Na+-H+ exchange or vacuolar-type H+-ATPase activity. 5. The three actions of secretin on guinea-pig pancreatic duct cells described in this and the accompanying paper - stimulation of a relatively Cl--insensitive luminal HCO3- efflux pathway, stimulation of basolateral Na+-HCO3- cotransport, and lack of effect on intracellular pH - require the current model of pancreatic HCO3- secretion to be modified.
Abstract.
Wilson RW, Wood CM, Houlihan DF (1996). Growth and protein turnover during acclimation to acid and aluminum in juvenile rainbow trout (Oncorhynchus mykiss).
Canadian Journal of Fisheries and Aquatic Sciences,
53(4), 802-811.
Abstract:
Growth and protein turnover during acclimation to acid and aluminum in juvenile rainbow trout (Oncorhynchus mykiss)
Growth, feeding, and protein synthesis (ks) and degradation (kd) in gill, liver, and whole body were measured in juvenile rainbow trout, Oncorhynchus mykiss, during 32 days exposure to sublethal acid (pH 5.2) and acid + aluminum (Al) (30 μg·L-1) in soft water. The only effects observed for exposure to acid alone were depressions of gill ks (17%) and kd (27%) after 15 days (data not available after day 15). Exposure to acid + Al caused a loss of appetite, a 73% reduction in whole body growth rate, and a 36% reduction in whole body ks during the first 7 days; all of these subsequently recovered, although mean body weight was still significantly depressed after 32 days. Gill ks and kd were greatly stimulated after 7 days and gill ks remained elevated after 32 days, suggesting a chronic cost of gill repair and (or) acclimatory processes even after physiological recovery was achieved. However, this elevated cost was small relative to the whole animal protein synthesis budget. Other chronic effects included suppressed liver ks and kd, reduced whole body translational efficiency, and enlarged liver size. Conversion of food into growth was paradoxically increased throughout all stages of acid + Al exposure but may have been the result of reduced routine activity. © 1996 NRC Canada.
Abstract.
Wilson RW, Gilmour KM, Henry RP, Wood CM (1996). Intestinal base excretion in the seawater-adapted rainbow trout: a role in acid-base balance?.
Journal of Experimental Biology,
199(10), 2331-2343.
Abstract:
Intestinal base excretion in the seawater-adapted rainbow trout: a role in acid-base balance?
A potential role for the intestine of seawater-adapted teleosts in acid- base regulation was investigated following earlier reports of highly alkaline rectal fluids in the gulf toadfish Opsanus beta. Rectal samples taken from starved seawater-adapted rainbow trout had a high fluid pH (8.90 ± 0.03; mean ± S.E.M. N=13) and base (HCO3- + 2CO32-) content of 157±26 mequiv kg-1 (N=11). In trout fitted with rectal catheters, rectal fluid was voided at a rate of 0.47±0.11 ml kg-1 h-1 (N=8), giving a net base excretion rate of 114±15 μequiv kg-1 h-1 (N=7). Drinking rates averaged 3.12±0.48 ml kg-1 h-1 (N=8), and accounted for only 6% of the base excreted via the intestine, indicating substantial net transport of endogenously derived base into the intestine. Rectally excreted base was approximately balanced by an equivalent efflux of net acid from non-rectal sources (possibly as NH4+ excretion via the gills). Samples taken from four sites along the intestine revealed that the most anterior region (the pyloric intestine) was responsible for the majority of HCO3-+2CO32- accumulation. The pyloric intestine was subsequently perfused in situ to investigate possible mechanisms of base secretion. Net base fluxes were found to be dependent on luminal Cl-, 76% stimulated by amiloride, 20% inhibited by 10-4 mol l-1 acetazolamide, but unaffected by either 10-4 mol l-1 SITS or 2x10-5 mol l-1 DIDS. This suggests that the mechanism of base secretion within the pyloric intestine may involve a Cl-/HCO3--ATPase. It is speculated that intestinal base secretion may play a role in facilitating osmoregulation of seawater-adapted teleosts.
Abstract.
