Direct calorimetric studies on the metabolic rate of Gammarus oceanicus from the brackish waters of the Baltic Sea (original) (raw)
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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.
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.
Thermochimica Acta, 2005
The heat production rate of the euryhaline isopod Idotea chelipes inhabiting two geographically and ecologically different regions, the Gulf of Gdansk (6.8 psu) (psu, practical salinity unit) and the Mecklenburg Bay (11.8 psu), was examined by direct calorimetry. The wet weights of specimens from the two regions varied from 0.005 to 0.030 g and between 0.004 and 0.036 g for I. chelipes from the Gulf of Gdansk and Mecklenburg Bay, respectively, and were not statistically different (P > 0.05). Animals that exhibited locomotor activity were characterized by metabolic rates higher by 12-77% compared to those of inactive specimens. The mean specific metabolic rates of I. chelipes from the Gulf of Gdansk and Mecklenburg Bay were 7.5 ± 3.4 J h −1 g −1 ww (n = 28) and 8.4 ± 2.6 J h −1 g −1 ww (n = 28), respectively. Metabolic rates of males and females were not significantly different (P > 0.05). The statistically significant (P < 0.05) relationship between specific metabolic rate (SMR) and wet weight (ww) was described within the experimental mass range by the power functions SMR 1 = 0.53ww −0.56 1 (R = −0.48) for I. chelipes from the Gulf of Gdansk and SMR 2 = 0.32ww −0.75 2 (R = −0.63) for those from Mecklenburg Bay.
Adaptation of Gammarus tigrinus Sexton, 1939 to new environments—Some metabolic investigations
Thermochimica Acta, 2007
The heat dissipation rates of the invasive amphipod Gammarus tigrinus Sexton, 1939 of the southern Baltic Sea were measured by means of direct calorimetry at the habitat salinity of 7‰ (males and females) and after gradual acclimation (only males) to lower (3‰) and higher (13‰ and 19.5‰) values (T = 18 • C). The mean specific metabolic rate at 7‰ amounted to 1.67 ± 0.86 mW g −1 ww (n = 25, average wet weight 10.9 ± 5.1 mg). Due to the sexual dimorphism and the smaller size of the females their specific metabolic rates were two-fold higher than that of males. Animals exposed to lower than habitat salinity insignificantly increased their specific metabolic rate by 42.5%. A reduction of 37.5% was observed when they were subjected to the highest examined salinity (19.5‰). G. tigrinus was thus able to change its metabolic rate by 56% in the studied salinity range from 3‰ to 19.5‰
Estimation of the proportion of metabolically active mass in the amphipod Gammarus fossarum
Freshwater Biology, 2003
1. The proportion of metabolically active mass in the freshwater amphipod Gammarus fossarum was determined using different parameters [chemical oxygen demand (COD), total nitrogen (N tot ), total phosphorus (P tot ) and mass of chitinous cuticle]. 2. The results of linear regressions between body mass and body length, and measured parameters (COD, N tot , P tot ) show high correlation coefficients for both fresh and the dry animals. The proportion of chitinous mass increased with body size. 3. Chemical analysis of P tot in individuals appears to be the most appropriate parameter for quantitating the metabolically active tissues in animals. 4. The dependence of the intensity of electron transport system (ETS) activity per protoplasm, calculated from the P tot and dry mass of animals, shows that large animals have the same ETS activity per unit of protoplasm as smaller ones. 5. We conclude that the chitinous mass is not the only factor which contributes to negative allometry of metabolic activity in G. fossarum.
Metabolic investigations of aquatic organisms with a new twin heat conduction calorimeter
Thermochimica Acta, 2007
A twin heat conduction calorimeter is presented that was specially developed as a modular design to allow for easy adaptation to changing experimental conditions. The instrument was built at the Institute of Oceanography, University of Gdansk, Poland for metabolic investigations and locomotor monitoring of aquatic organisms under different environmental conditions (e.g., salinity, temperature, oxygen tension, and pollutants) as well as physiological ones (age, sex, pregnancy, and adaptation to changing external parameters). This calorimeter has flatter and broader 24-ml vessels (height 50 mm and diameter 28 mm) than usual instruments to allow larger aquatic invertebrates to swim around during the experiment. The sensitivity is 99.1 V mW −1 , and the time constant is 217 s with 15 ml water and 146 s without water in the vessels. Construction details are presented in this paper and the first results are given for three aquatic crustaceans of different taxonomic groups: the isopod Idotea chelipes, the amphipod Gammarus tigrinus and the decapod Rhithropanopeus harrisii.
Comparative metabolic rates of common western North Atlantic Ocean sciaenid fishes
Journal of Fish Biology, 2011
The resting metabolic rates (R R ) of western North Atlantic Ocean sciaenids, such as Atlantic croaker Micropogonias undulatus, spot Leiostomus xanthurus and kingfishes Menticirrhus spp., as well as the active metabolic rates (R A ) of M. undulatus and L. xanthurus were investigated to facilitate inter and intraspecific comparisons of their energetic ecology. The R R of M. undulatus and L. xanthurus were typical for fishes with similar lifestyles. The R R of Menticirrhus spp. were elevated relative to those of M. undulatus and L. xanthurus, but below those of high-energy-demand species such as tunas Thunnus spp. and dolphinfish Coryphaena hippurus. Repeated-measures non-linear mixed-effects models were applied to account for within-individual autocorrelation and corrected for non-constant variance typical of noisy R A data sets. Repeated-measures models incorporating autoregressive first-order [AR(1)] and autoregressive moving average (ARMA) covariances provided significantly superior fits, more precise parameter estimates (i.e. reduced s.e.) and yintercept estimates that more closely approximated measured R R for M. undulatus and L. xanthurus than standard least-squares regression procedures.
Journal of fish biology, 2016
Accounting for energy use by fishes has been taking place for over 200 years. The original, and continuing gold standard for measuring energy use in terrestrial animals, is to account for the waste heat produced by all reactions of metabolism, a process referred to as direct calorimetry. Direct calorimetry is not easy or convenient in terrestrial animals and is extremely difficult in aquatic animals. Thus, the original and most subsequent measurements of metabolic activity in fishes have been measured via indirect calorimetry. Indirect calorimetry takes advantage of the fact that oxygen is consumed and carbon dioxide is produced during the catabolic conversion of foodstuffs or energy reserves to useful ATP energy. As measuring [CO2 ] in water is more challenging than measuring [O2 ], most indirect calorimetric studies on fishes have used the rate of O2 consumption. To relate measurements of O2 consumption back to actual energy usage requires knowledge of the substrate being oxidized...
Marine Biology, 1990
Acutely elevated seawater temperatures had pronounced metabolic effect on the Arctic under-ice amphipods Gammarus wilkitzkii and Onisimus glacialis, collected in May 1986 and 1988 in the Barents Sea. An increased rate of oxygen consumption vs temperature was observed for both species. In the range from 0 ° to 10 °C G. wilkitzkii and O. glacialis exhibit Qto values of 3.4 and 3.6, respectively. The results also indicate increased ammonia excretion rates for G. wilkitzkii and O. glacialis by an elevation of temperature from 0 ° to 10°C, with an overall Qt0 of 1.9 and 2.3, respectively. The present study demonstrates an increased O : N ratio with ambient temperature elevation from 0 ° to 10 °C for G. wilkitzkii and O. glacialis, with overall Q~o values of 2.0 and 1.6, respectively. This indicates a temperature-induced change in the metabolic substrate towards lipids.