Metabolic investigations of aquatic organisms with a new twin heat conduction calorimeter (original) (raw)
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Thermochimica Acta, 1994
A system for computerized registration of heat production data and oxygen tension values of a differential 1 litre flow-through microcalorimeter (Setaram GF 108) is described. The linked values of oxygen concentration and heat production data were simultaneously stored on a computer. The aerobic and total heat production rates were thus measured of goldfish (Curassius auratus L.) during normoxia, hypoxia and anoxia exposure. Incidentally, a partial anaerobic response was observed in goldfish during normoxia. During severe hypoxia and anoxia, goldfish respond with a reduction of the metabolic rate and a strong increase of anaerobic heat production. From the linked oxygen consumption and heat production data, the oxycaloric equivalent was calculated. The described system enables us to study continuously the effects of environmental factors on the metabolic rate of aquatic organisms.
Direct calorimetry of aquatic animals: Dynamic response of biological processes
Thermochimica Acta, 1995
The theory of system identification was used to determine the time constant T of a 1 litre flow through differential calorimeter (Setaram GF 108) at a flow rate of 50 ml min-'_ By numerical differentiation the impulse response function g(t). the time derivative of the step response,f(r), was calculated. With the aid of the Prony method, the time constant a2 of the time-discrete system of the decimated dataset was calculated, giving a mean value of 0.7402 k 0.0044 (n = 4). This value was converted to the time constant T of the time-continuous system, giving a value of 33.25 k 0.65 min (n = 4). The description of the system agreed with a model for a first order process. For control of the time constant value, the step response ,f(r) and the impulse response g(t) signal were simulated from the original block diagram u(t) which gave a suitable fit. Via the technique of deconvolution, the datasets of a biological case study with goldfish (Cuuassius uurutus L.) were desmeared to describe the dynamic responses of the biological processes in the calorimetric vessel with a much reduced time constant T. Finally, the timescale on which the process of metabolic depression takes place in this species during anaerobiosis was estimated to be several minutes.
2018
Considering that swim-flume or chasing methods fail in the estimation of maximum metabolic rate and in the estimation of Aerobic Scope (AS) of sedentary or sluggish aquatic ectotherms, we propose a novel conceptual approach in which high metabolic rates can be obtained through stimulation of organism metabolic activity using high and low non-lethal temperatures that induce high (HMR) and low metabolic rates (LMR), This method was defined as TIMR: Temperature Induced Metabolic Rate, designed to obtain an aerobic power budget based on temperature-induced metabolic scope which may mirror thermal metabolic scope (TMS = HMR—LMR). Prior to use, the researcher should know the critical thermal maximum (CT max) and minimum (CT min) of animals, and calculate temperature TIMR max (at temperatures −5–10% below CT max) and TIMR min (at temperatures +5–10% above CT min), or choose a high and low non-lethal temperature that provoke a higher and lower metabolic rate than observed in routine conditions. Two sets of experiments were carried out. The first compared swim-flume open respirometry and the TIMR protocol using Centropomus undecimalis (snook), an endurance swimmer, acclimated at different temperatures. Results showed that independent of the method used and of the magnitude of the metabolic response, a similar relationship between maximum metabolic budget and acclimation temperature was observed, demonstrating that the TIMR method allows the identification of TMS. The second evaluated the effect of acclimation temperature in snook, semi-sedentary yellow tail (Ocyurus chrysurus), and sedentary clownfish (Amphiprion ocellaris), using TIMR and the chasing method. Both methods produced similar maximum metabolic rates in snook
Direct calorimetric studies on the metabolic rate of from the brackish waters of the Baltic Sea
Thermochimica Acta, 2004
Heat production rates of the benthic amphipod Gammarus oceanicus from the brackish waters of the Gulf of Gdansk were measured by means of direct calorimetry at their usual ambient ("habitat") salinity (7‰) and 10 • C. Animals exhibited locomotor activity during the measurements, so that the total metabolic rate was the sum of both resting and active metabolism. The mean specific metabolic rate amounted to 1.57 ± 0.61 mW g −1 wet weight (ww) (n = 73, average wet weight 67.2 ± 34.0 mg). Smallest animals with a mean wet weight of 24.5 ± 3.4 mg exhibited the highest specific metabolic rates with 2.24 ± 0.57 mW g −1 ww (n = 10), whereas the largest ones with wet weights of 117.7 ± 19.4 mg showed the lowest values with 1.10 ± 0.32 mW g −1 ww (n = 15). There was a significant negative correlation (R 2 = 0.49, P < 0.05) between the specific metabolic rate of G. oceanicus and its wet weight. The metabolic rate of females was higher by 29% (P < 0.05) than that of males of the same length due to the differences in wet weight.
Thermochimica Acta, 2004
Heat production rates of the benthic amphipod Gammarus oceanicus from the brackish waters of the Gulf of Gdansk were measured by means of direct calorimetry at their usual ambient ("habitat") salinity (7‰) and 10 • C. Animals exhibited locomotor activity during the measurements, so that the total metabolic rate was the sum of both resting and active metabolism. The mean specific metabolic rate amounted to 1.57 ± 0.61 mW g −1 wet weight (ww) (n = 73, average wet weight 67.2 ± 34.0 mg). Smallest animals with a mean wet weight of 24.5 ± 3.4 mg exhibited the highest specific metabolic rates with 2.24 ± 0.57 mW g −1 ww (n = 10), whereas the largest ones with wet weights of 117.7 ± 19.4 mg showed the lowest values with 1.10 ± 0.32 mW g −1 ww (n = 15). There was a significant negative correlation (R 2 = 0.49, P < 0.05) between the specific metabolic rate of G. oceanicus and its wet weight. The metabolic rate of females was higher by 29% (P < 0.05) than that of males of the same length due to the differences in wet weight.
Low global sensitivity of metabolic rate to temperature in calcified marine invertebrates
Oecologia, 2014
of calcified invertebrates (bivalves, gastropods, urchins and brachiopods), using a single consistent methodology, including 11 species whose sMr was described for the first time. sMr of 15 out of 17 species had a mass-scaling exponent between 2/3 and 1, with no greater support for a 3/4 rather than a 2/3 scaling exponent. after accounting for taxonomy and variability in parameter estimates among species using variance-weighted linear mixed effects modelling, temperature sensitivity of sMr had an activation energy (Ea) of 0.16 for both northern and southern hemisphere species which was lower than predicted under the metabolic theory of ecology (Ea 0.2-1.2 eV). northern hemisphere species, however, had a higher sMr at each habitat temperature, but a lower mass-scaling exponent relative to sMr. evolutionary trade-offs that may be driving Abstract Metabolic rate is a key component of energy budgets that scales with body size and varies with largescale environmental geographical patterns. here we conduct an analysis of standard metabolic rates (sMr) of marine ectotherms across a 70° latitudinal gradient in both hemispheres that spanned collection temperatures of 0-30 °c. To account for latitudinal differences in the size and skeletal composition between species, sMr was mass normalized to that of a standard-sized (223 mg) ash-free dry mass individual. sMr was measured for 17 species communicated by craig Osenberg.
Thermochimica Acta, 1997
In order to correlate the metabolic rate and locomotor activity level of fish, a calorimetric system (S~taram GF 108) was supplemented with a video tracking and motion analysis system. The motion analysis system is based on digital image processing. Once every second, two images (with an interval of 120 ms) are digitized and subtracted. The difference between the two images is used as a measure of the animal's movement. The activity of different complex movements, like turning, accelerations, fin movements, and branchial ventilation, were thus quantified. The combination of motion analysis with calorimetry gave some interesting results. Firstly, during extreme hypoxia, tilapia does not become lethargic as has been described for the anoxia-tolerant crucian carp [1]. The locomotor activity level during severe hypoxia corresponded to the locomotor activity level during normoxia in the restricted area of the calorimetric vessel. This implies that the calorimetrically determined reduction of the heat flux by 50% under these conditions can be ascribed to a reduction in the cellular energy metabolism -metabolic depression. Secondly, the metabolic rate under constant light conditions was elevated from 11-18%, and the animals showed strong fluctuations in the heat flux; periods of aerobic metabolism alternated with periods of anaerobic metabolism. This was in contrast to the experiments under constant dark conditions in which the metabolic rate was around the standard metabolic rate (SMR). Under the applied conditions, no correlation was observed between heat production measurements and locomotor activity. This may possibly be ascribed to the limited size of the calorimetric vessel in which the animals' metabolic rates were around SMR. The observed oscillations in metabolic rate under light conditions could be another disrupting factor; oscillations in the circulation and ventilation could be responsible for this phenomenon.
Heat production rate of the Baltic amphipod Gammarus oceanicus at varying salinities
Thermochimica Acta, 2004
The heat production rate of Gammarus oceanicus, a species of marine origin living in the brackish waters (7 psu (practical salinity units)), was examined by direct calorimetry after acclimation to salinities of 5, 7, 14, 20 and 30 psu (at 10 °C). The mean heat dissipation was greatest at 5 psu with 5.64±1.60 J h−1 g−1 ww (wet weight) and decreased significantly (P<0.05) with increasing salinity down to 2.26±1.14 J h−1 g−1 ww at 30 psu. The high inter-individual variability was of significance for the obtained results. When salinity dropped by only 2 psu from the control (7 psu) the mean heat production rate raised by 18%. A salinity increase from 7 to 30 psu caused a reduction in the average metabolic rate of G. oceanicus by 53%. That means that G. oceanicus requires more energy for osmotic adjustment at lower salinities.
A novel approach to measuring heat flux in swimming animals
Journal of Experimental Marine Biology and Ecology, 2005
We present a design for long-term or removable attachment of heat flux sensors (HFSs) to stationary or swimming animals in water that enables collection of heat flux data on both captive and free-ranging pinnipeds. HFSs were modified to allow for independent, continuous, and long-term or removable attachment to study animals. The design was tested for effects of HFSs and the attachment mechanism on resultant heat flux. Effects were insulative and consistent across water temperatures and flow speeds, resulting in a correction factor of 3.42. This correction factor was applied to all measurements of heat flux from animal experiments to account for the thermal resistance of HFSs and insulative effects of the attachment mechanism. Heat flux and skin temperature data were collected from two captive Steller sea lions (Eumetopias jubatus) as they swam in a large habitat tank over time periods ranging from approximately 4 to 9 min. Of the 72 HFSs deployed using the attachment mechanism, data were successfully retrieved from 70. The HFS attachment mechanism was also used on two wild free-ranging Weddell seals (Leptonychotes weddellii) off Ross Island, Antarctica, for up to 7 days. Heat flux data were retrieved from all eight sensors deployed. These results, along with those from Steller sea lions, suggest that HFSs can be deployed with success on captive and wild animals using the designed attachment mechanism. D