scholarly journals Diet mediates thermal performance traits: implications for marine ectotherms

2021 ◽  
Author(s):  
Emily A. Hardison ◽  
Krista Kraskura ◽  
Jacey Van Wert ◽  
Tina Nguyen ◽  
Erika J. Eliason
Keyword(s):  
Metabolic Rate ◽  
Thermal Performance ◽  
Building Blocks ◽  
Standard Metabolic Rate ◽  
Temperature Acclimation ◽  
Thermal Acclimation ◽  
Seasonal Temperature ◽  
Sprint Speed ◽  
Trade Offs ◽  
Ad Libitum

Thermal acclimation is a key process enabling ectotherms to cope with temperature change. To undergo a successful acclimation response, ectotherms require energy and nutritional building blocks obtained from their diet. However, diet is often overlooked as a factor that can alter acclimation responses. Using a temperate omnivorous fish, opaleye (Girella nigricans), as a model system, we tested the hypotheses that 1) diet can impact the magnitude of thermal acclimation responses and 2) traits vary in their sensitivity to both temperature acclimation and diet. We fed opaleye a simple omnivorous diet (ad libitum Artemia sp. and Ulva sp.) or a carnivorous diet (ad libitum Artemia sp.) at two ecologically relevant temperatures (12 and 20°C) and measured a suite of whole animal (growth, sprint speed, metabolism), organ (cardiac thermal tolerance), and cellular-level traits (oxidative stress, glycolytic capacity). When opaleye were offered two diet options compared to one, they had reduced cardiovascular thermal performance and higher standard metabolic rate under conditions representative of the maximal seasonal temperature the population experiences (20°C). Further, sprint speed and absolute aerobic scope were insensitive to diet and temperature, while growth was highly sensitive to temperature but not diet, and standard metabolic rate and maximum heart rate were sensitive to both diet and temperature. Our results reveal that diet influences thermal performance in trait-specific ways, which could create diet trade-offs for generalist ectotherms living in thermally variable environments. Ectotherms that alter their diet may be able to regulate their performance at different environmental temperatures.

Physiological basis of metabolic trade-offs between growth and performance among different strains of rainbow trout

2016 ◽  
Vol 73 (10) ◽  
pp. 1493-1506 ◽  
Author(s):  
David Allen ◽  
Jordan Rosenfeld ◽  
Jeffrey Richards
Keyword(s):  
Rainbow Trout ◽  
Metabolic Rate ◽  
Energy Content ◽  
Environmental Gradients ◽  
High Growth ◽  
Growth Efficiency ◽  
Standard Metabolic Rate ◽  
Physiological Basis ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Trade Offs

Adaptive trade-offs define the trait combinations that differentiate taxa and allow coexistence along environmental gradients. To understand the physiological trade-offs associated with growth, we examined relationships among metabolic rate, digestive capacity, tissue energy content, and growth in juveniles of three strains of rainbow trout (Oncorhynchus mykiss) that differ in growth. Fish were reared under satiation, 1% of body mass per day, and complete food deprivation treatments to assess differences in performance and adaptive trade-offs along a gradient of resource availability. The fast-growing hatchery strain had higher standard metabolic rate (SMR), lower aerobic scope, and potentially lower maximum metabolic rates, suggesting that high growth trades off against a reduced capacity to do metabolic work. Trout with high growth rates also generally had larger gastrointestinal tracts, maximum food consumption, and growth efficiency. Results demonstrate (i) higher SMR of fast growers appears to be related to a greater investment in high-maintenance digestive tissue that supports rapid growth; (ii) growth appears to trade off against active metabolism; and (iii) selection on growth involves a suite of integrated physiological and anatomical traits that are affected by both genotype and environment (ration).

scholarly journals Climate change in fish: effects of respiratory constraints on optimal life history and behaviour

2015 ◽  
Vol 11 (2) ◽  
pp. 20141032 ◽  
Author(s):  
Rebecca E. Holt ◽  
Christian Jørgensen
Keyword(s):  
Metabolic Rate ◽  
Life Histories ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Standard Metabolic Rate ◽  
Aerobic Scope ◽  
Trade Offs ◽  
Different Temperatures ◽  
The Difference ◽  
Common Trade

The difference between maximum metabolic rate and standard metabolic rate is referred to as aerobic scope, and because it constrains performance it is suggested to constitute a key limiting process prescribing how fish may cope with or adapt to climate warming. We use an evolutionary bioenergetics model for Atlantic cod ( Gadus morhua ) to predict optimal life histories and behaviours at different temperatures. The model assumes common trade-offs and predicts that optimal temperatures for growth and fitness lie below that for aerobic scope; aerobic scope is thus a poor predictor of fitness at high temperatures. Initially, warming expands aerobic scope, allowing for faster growth and increased reproduction. Beyond the optimal temperature for fitness, increased metabolic requirements intensify foraging and reduce survival; oxygen budgeting conflicts thus constrain successful completion of the life cycle. The model illustrates how physiological adaptations are part of a suite of traits that have coevolved.

scholarly journals Temperature acclimation rate of aerobic scope and feeding metabolism in fishes: implications in a thermally extreme future

2014 ◽  
Vol 281 (1794) ◽  
pp. 20141490 ◽  
Author(s):  
Erik Sandblom ◽  
Albin Gräns ◽  
Michael Axelsson ◽  
Henrik Seth
Keyword(s):  
Metabolic Rate ◽  
Time Course ◽  
Standard Metabolic Rate ◽  
Temperature Acclimation ◽  
Specific Dynamic Action ◽  
Energetic Cost ◽  
Aerobic Scope ◽  
Postprandial Metabolism ◽  
Myoxocephalus Scorpius ◽  
Maximum Metabolic Rate

Temperature acclimation may offset the increased energy expenditure (standard metabolic rate, SMR) and reduced scope for activity (aerobic scope, AS) predicted to occur with local and global warming in fishes and other ectotherms. Yet, the time course and mechanisms of this process is little understood. Acclimation dynamics of SMR, maximum metabolic rate, AS and the specific dynamic action of feeding (SDA) were determined in shorthorn sculpin ( Myoxocephalus scorpius ) after transfer from 10°C to 16°C. SMR increased in the first week by 82% reducing AS to 55% of initial values, while peak postprandial metabolism was initially greater. This meant that the estimated AS during peak SDA approached zero, constraining digestion and leaving little room for additional aerobic processes. After eight weeks at 16°C, SMR was restored, while AS and the estimated AS during peak SDA recovered partly. Collectively, this demonstrated a considerable capacity for metabolic thermal compensation, which should be better incorporated into future models on organismal responses to climate change. A mathematical model based on the empirical data suggested that phenotypes with fast acclimation rates may be favoured by natural selection as the accumulated energetic cost of a slow acclimation rate increases in a warmer future with exacerbated thermal variations.

scholarly journals Ecological and evolutionary consequences of metabolic rate plasticity in response to environmental change

2019 ◽  
Vol 374 (1768) ◽  
pp. 20180180 ◽  
Author(s):  
Tommy Norin ◽  
Neil B. Metcalfe
Keyword(s):  
Environmental Change ◽  
Metabolic Rate ◽  
Intraspecific Variation ◽  
Standard Metabolic Rate ◽  
Metabolic Rates ◽  
Trade Offs ◽  
Fitness Consequences ◽  
Organ Tissue ◽  
Evolutionary Consequences ◽  
Response To Environmental Change

Basal or standard metabolic rate reflects the minimum amount of energy required to maintain body processes, while the maximum metabolic rate sets the ceiling for aerobic work. There is typically up to three-fold intraspecific variation in both minimal and maximal rates of metabolism, even after controlling for size, sex and age; these differences are consistent over time within a given context, but both minimal and maximal metabolic rates are plastic and can vary in response to changing environments. Here we explore the causes of intraspecific and phenotypic variation at the organ, tissue and mitochondrial levels. We highlight the growing evidence that individuals differ predictably in the flexibility of their metabolic rates and in the extent to which they can suppress minimal metabolism when food is limiting but increase the capacity for aerobic metabolism when a high work rate is beneficial. It is unclear why this intraspecific variation in metabolic flexibility persists—possibly because of trade-offs with the flexibility of other traits—but it has consequences for the ability of populations to respond to a changing world. It is clear that metabolic rates are targets of selection, but more research is needed on the fitness consequences of rates of metabolism and their plasticity at different life stages, especially in natural conditions. This article is part of the theme issue ‘The role of plasticity in phenotypic adaptation to rapid environmental change’.

scholarly journals Physiological basis of temperature-dependent biogeography: trade-offs in muscle design and performance in polar ectotherms

2002 ◽  
Vol 205 (15) ◽  
pp. 2217-2230 ◽  
Author(s):  
H. O. Pörtner
Keyword(s):  
Metabolic Rate ◽  
Aerobic Capacity ◽  
Anaerobic Capacity ◽  
Standard Metabolic Rate ◽  
High Energy ◽  
The Arctic ◽  
Aerobic Scope ◽  
Physiological Basis ◽  
Activity Maximum ◽  
Trade Offs

SUMMARYPolar, especially Antarctic, oceans host ectothermic fish and invertebrates characterized by low-to-moderate levels of motor activity; maximum performance is reduced compared with that in warmer habitats. The present review attempts to identify the trade-offs involved in adaptation to cold in the light of progress in the physiology of thermal tolerance. Recent evidence suggests that oxygen limitations and a decrease in aerobic scope are the first indications of tolerance limits at both low and high temperature extremes. The cold-induced reduction in aerobic capacity is compensated for at the cellular level by elevated mitochondrial densities, accompanied by molecular and membrane adjustments for the maintenance of muscle function. Particularly in the muscle of pelagic Antarctic fish, among notothenioids, the mitochondrial volume densities are among the highest known for vertebrates and are associated with cold compensation of aerobic metabolic pathways, a reduction in anaerobic scope, rapid recovery from exhaustive exercise and enhanced lipid stores as well as a preference for lipid catabolism characterized by high energy efficiency at high levels of ambient oxygen supply. Significant anaerobic capacity is still found at the very low end of the activity spectrum, e.g. among benthic eelpout (Zoarcideae).In contrast to the cold-adapted eurytherms of the Arctic, polar (especially Antarctic) stenotherms minimize standard metabolic rate and, as a precondition, the aerobic capacity per milligram of mitochondrial protein,thereby minimizing oxygen demand. Cost reductions are supported by the downregulation of the cost and flexibility of acid—base regulation. At maintained factorial scopes, the reduction in standard metabolic rate will cause net aerobic scope to be lower than in temperate species. Loss of contractile myofilaments and, thereby, force results from space constraints due to excessive mitochondrial proliferation. On a continuum between low and moderately high levels of muscular activity, polar fish have developed characteristics of aerobic metabolism equivalent to those of high-performance swimmers in warmer waters. However, they only reach low performance levels despite taking aerobic design to an extreme.

Field-Testing a Standard Metabolic Rate Estimation Technique for Eastern Red-Backed Salamanders

2016 ◽  
Vol 50 (1) ◽  
pp. 138-144
Author(s):  
Patrick J Ruhl ◽  
Robert N Chapman ◽  
John B. Dunning
Keyword(s):  
Metabolic Rate ◽  
Field Testing ◽  
Standard Metabolic Rate ◽  
Estimation Technique ◽  
Rate Estimation

Thermal acclimation and muscle contractile properties in cyprinid fish

1990 ◽  
Vol 259 (2) ◽  
pp. R231-R236 ◽  
Author(s):  
I. A. Johnston ◽  
J. D. Fleming ◽  
T. Crockford
Keyword(s):  
Molecular Mechanisms ◽  
Swimming Performance ◽  
Force Production ◽  
Rutilus Rutilus ◽  
Temperature Acclimation ◽  
Thermal Acclimation ◽  
Contractile Properties ◽  
Locomotory Activity ◽  
Roach Rutilus Rutilus ◽  
Goldfish Carassius Auratus

After several weeks of cold acclimation, the swimming performance of some fish is increased at low temperatures and decreased at high temperatures. The temperature compensation of locomotory activity involves changes in central patterns of muscle fiber recruitment and in the properties of the peripheral nervous system and muscle tissues. In some freshwater fish belonging to the family Cyprinidae, including the goldfish (Carassius auratus), the common carp (Cyprinus carpio), and the roach (Rutilus rutilus), the intrinsic contractile properties of muscles are modified by thermal acclimation. Parameters that can be altered by temperature acclimation in both fast and slow muscle fibers include isometric twitch contraction time, maximum force production, and unloaded shortening speed. The molecular mechanisms responsible for these changes in contractility are discussed.

High Yield Assembly of Compliant MEMS Snap Fasteners

2008 ◽  
Author(s):  
Rakesh Murthy ◽  
Aditya N. Das ◽  
Dan O. Popa
Keyword(s):  
Self Assembly ◽  
Building Blocks ◽  
Deformation Energy ◽  
High Yield ◽  
3 Dimensional ◽  
Lab Experiments ◽  
Trade Offs ◽  
Robotic Cells ◽  
And Performance ◽  
Important Design

Heterogeneous assembly at the microscale has recently emerged as a viable pathway to constructing 3-dimensional microrobots and other miniaturized devices. In contrast to self-assembly, this method is directed and deterministic, and is based on serial or parallel microassembly. Whereas at the meso and macro scales, automation is often undertaken after, and often benchmarked against manual assembly, we demonstrate that deterministic automation at the MEMS scale can be completed with higher yields through the use of engineered compliance and precision robotic cells. Snap fasteners have long been used as a way to exploit the inherent stability of local minima of the deformation energy caused by interference during part mating. In this paper we assume that the building blocks are 2 1/2 -dimensional, as is the case with lithographically microfabricated MEMS parts. The assembly of the snap fasteners is done using μ3, a multi-robot microassembly station with unique characteristics located at our ARRI’s Texas Microfactory lab. Experiments are performed to demonstrate that fast and reliable assemblies can be expected if the microparts and the robotic cell satisfy a so-called “High Yield Assembly Condition” (H.Y.A.C.). Important design trade-offs for assembly and performance of microsnap fasteners are discussed and experimentally evaluated.

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