scholarly journals Metabolic rates of the antarctic amphipod Gondogeneia antarctica at different temperatures and salinities

2013 ◽  
Vol 61 (4) ◽  
pp. 243-249 ◽  
Author(s):  
Vicente Gomes ◽  
Maria José de Arruda Campos Rocha Passos ◽  
Arthur José da Silva Rocha ◽  
Thais da Cruz Alves dos Santos ◽  
Alex Sander Dias Machado ◽  
...  
Keyword(s):  
Energy Demand ◽  
Ammonia Excretion ◽  
Metabolic Rates ◽  
Metabolic Compensation ◽  
Adaptive Mechanisms ◽  
Stable Conditions ◽  
Different Temperatures ◽  
Antarctic Amphipod ◽  
Excretion Rates ◽  
The Antarctic

Changes in environmental factors may deeply affect the energy budget of Antarctic organisms as many of them are stenothermal and/or stenohaline ectotherms. In this context, the aim of this study is to contribute to knowledge on variations in the energy demand of the Antarctic amphipod, Gondogeneia antarctica as a function of temperature and salinity. Experiments were held at the Brazilian Antarctic Station "Comandante Ferraz", under controlled conditions. Animals collected at Admiralty Bay were acclimated to temperatures of 0ºC; 2.5ºC and 5ºC and to salinities of 35, 30 and 25. Thirty measurements were made for each of the nine combinations of the three temperatures and three salinities, totalling 270 measurements. Metabolic rates were assessed by oxygen consumption and total nitrogenous ammonia excretion, in sealed respirometers. When acclimated to salinities 30 or 35, metabolic rates at 0ºC and 2.5ºC were very similar indicating a possible mechanism of metabolic compensation for temperature. At 5.0ºC, however, metabolic rates were always higher. Lower salinities enhanced the effects of temperature on metabolism and ammonia excretion rates. The physiological adaptations of individuals of G. antarctica suggest adaptive mechanisms for energy saving, adjusted to an environment with stable conditions of temperature and salinity. Little is known about the joint effects of salinity and temperature and this study is an important contribution to the understanding of the mechanism of polar organisms in their adaptation to both factors.

scholarly journals OXYGEN CONSUMPTION AND AMMONIA EXCRETION OF THE ANTARCTIC AMPHIPOD Bovallia gigantea PFEFFER, 1888, AT DIFFERENT TEMPERATURES AND SALINITIES

2014 ◽  
Vol 62 (4) ◽  
pp. 315-321 ◽  
Author(s):  
Vicente Gomes ◽  
Maria José de Arruda Campos Rocha Passos ◽  
Arthur José da Silva Rocha ◽  
Thais da Cruz Alves dos Santos ◽  
Fabio Matsu Hasue ◽  
...  
Keyword(s):  
Oxygen Consumption ◽  
Energy Demand ◽  
Ammonia Excretion ◽  
Global Changes ◽  
Metabolic Rates ◽  
Different Temperatures ◽  
Total Ammonia ◽  
Ecological Importance ◽  
Antarctic Amphipod ◽  
Excretion Rates

The energy budget of Antarctic stenothermic and/or stenohaline ectotherms is modulated by variations of temperature and salinity. The joint effects of these latter on polar organisms have been but little studied. Data on this subject are of great importance for an understanding of the energy demand of Antarctic animals such as amphipods, especially when considering their ecological importance and the possible impacts of global changes. Experiments were carried out at the Brazilian Antarctic Station "Comandante Ferraz" under controlled conditions. Specimens of Bovallia gigantea were collected in Admiralty Bay and acclimated to temperatures of 0ºC; 2.5ºC and 5ºC and to salinities of 35, 30 and 25. Thirty measurements were taken for each of the nine possible combinations of the three temperatures and the three salinities. Metabolic rates were assessed based on oxygen consumption and total ammonia nitrogenous excretion in sealed respirometers. At 0ºC and 2.5ºC, the metabolic rates of the animals that were acclimated to salinities of 30 or 35 were similar, indicating a possible mechanism of metabolic independence of temperature. However, the metabolic rates were always higher at 5.0ºC. The effects of temperature on oxygen consumption and on ammonia excretion rates were intensified by lower salinities. Individuals of B gigantea have a temperature-independent metabolic rate within a narrow temperature window that can be modified in accordance with salinity.

Metabolic activity of zooplankton from the Antarctic Ocean

1981 ◽  
Vol 32 (6) ◽  
pp. 921 ◽  
Author(s):  
T Ikeda ◽  
EH Fay
Keyword(s):  
Respiration Rate ◽  
Ammonia Excretion ◽  
Effect Of Temperature ◽  
Antarctic Ocean ◽  
Q10 Value ◽  
Ets Activity ◽  
The Family ◽  
Excretion Rates ◽  
The Antarctic ◽  
Ammonia Excretion Rate

Eight species of live zooplankton were transported from the Antarctic Ocean to a tropical laboratory in Queensland, Australia. Their respiration and ammonia excretion rates measured at - 0.5� C were in the order of 0.15-0.55 �l O2/mg dry wt. h and 0.002-0.06�g N mg dry wt. h, respectively. As an indirect estimate enzyme activity of the respiratory electron transport system (ETS) was determined on frozen specimens of 15 zooplankton species brought back from the Antarctic Ocean. The ratio of ETS activity to respiration rate measured in this study was 1.863 � 0.738 (n = 12). The respiration rates thus directly and indirectly obtained were in agreement with results of previous workers. Effect of temperature on respiration and ammonia excretion rates were examined on two selected animal groups of zooplankton- copepods belonging to the family Calanidae and euphausiids of the genus Euphausia- and the results were compared with those for species from other seas where the temperature varies from 5.0 to 27.6�C. From this comparison, acceleration of the rate (standardized to 1 mg dry wt of body) by the increase of temperature (expressed as a Q10 value) was 2.18 for respiration rate and 2.58 for ammonia excretion rate.

Changes in metabolic rate and N excretion in the marine invertebrateSipunculus nudusunder conditions of environmental hypercapnia

2002 ◽  
Vol 205 (8) ◽  
pp. 1153-1160 ◽  
Author(s):  
M. Langenbuch ◽  
H. O. Pörtner
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Metabolic Rate ◽  
Intracellular Ph ◽  
Energy Demand ◽  
Control Level ◽  
Ammonia Excretion ◽  
Amino Acid Catabolism ◽  
Acid Base ◽  
Selection Of

SUMMARYIncreased CO2 partial pressures (hypercapnia) as well as hypoxia are natural features of marine environments like the intertidal zone. Nevertheless little is known about the specific effects of CO2 on metabolism, except for the well-described effects on acid—base variables and regulation. Accordingly, the sediment-dwelling worm Sipunculus nudus was used as an experimental model to investigate the correlation of acid—base-induced metabolic depression and protein/amino acid catabolism, by determining the rates of oxygen consumption, ammonia excretion and O/N ratios in non-perfused preparations of body wall musculature at various levels of extra- and intracellular pH, PCO2 and [HCO3-]. A decrease in extracellular pH from control level (7.9) to 6.7 caused a reduction in aerobic metabolic rate of both normocapnic and hypercapnic tissues by 40-45 %. O/N ratios of 4.0-4.5 under control conditions indicate that amino acid catabolism meets the largest fraction of aerobic energy demand. A significant 10-15 % drop in ammonia excretion, a simultaneous reduction of O/N ratios and a transient accumulation of intracellular bicarbonate during transition to extreme acidosis suggest a reduction in net amino acid catabolism and a shift in the selection of amino acids used,favouring monoamino dicarboxylic acids and their amines (asparagine,glutamine, aspartic and glutamic acids). A drop in intracellular pH was identified as mediating this effect. In conclusion, the present data provide evidence for a regulatory role of intracellular pH in the selection of amino acids used by catabolism.

Ammonia, Urea and H+ Distribution and the Evolution of Ureotelism in Amphibians

1989 ◽  
Vol 144 (1) ◽  
pp. 215-233 ◽  
Author(s):  
CHRIS M. WOOD ◽  
R. S. MUNGER ◽  
D. P. TOEWS
Keyword(s):  
Cell Membrane ◽  
Teleost Fish ◽  
Transmembrane Potential ◽  
Rana Catesbeiana ◽  
Ammonia Excretion ◽  
Cell Membrane Permeability ◽  
Ambystoma Tigrinum ◽  
Amphibian Species ◽  
Necturus Maculosus ◽  
Excretion Rates

In theory, the distribution of ammonia across cell membranes (Tammi/Tamme) between intracellular and extracellular fluids (ICF and ECF) may be determined by the transmembrane pH gradient (as in mammals), the transmembrane potential (as in teleost fish), or both, depending on the relative permeability of the membranes to NH3 and NH4+ (pNH3/pNH4+). The resting distributions of H+ (via [14C]DMO), ammonia and urea between plasma and skeletal muscle, and the relative excretion rates of ammonia-N and urea-N, were measured in five amphibian species (Bufo marinus, Ambystoma tigrinum, Rana catesbeiana, Necturus maculosus and Xenopus laevis). Although ureai/ureae ratios were uniformly close to 1.0, Tammi/Tamme. ratios correlated directly with the degree of ammoniotelism in each species, ranging from 9.1 (Bufo, 10% ammoniotelic) to 16.7 (Xenopus, 79% ammoniotelic). These values are intermediate between ratios of about 30 (low pNH3/pNH4+) in ammoniotelic teleost fish and about 3 (high pNH3/pNH4+) in ureotelic mammals. The results indicate that amphibians represent a transitional stage in which ammonia distribution is influenced by both the pHi-pHe gradient and the membrane potential, and that a reduction in cell membrane permeability to NH4+ (i.e. increased pNH3/pNH4+) was associated with the evolution of ureotelism. Hyperosmotic saline exposure increased urea excretion 10-fold in Xenopus, while ammonia excretion remained unchanged. Tammi/Tamme fell, but this response was attributable to an abolition of the pHi-pHe gradient, rather than a physiological change in the cell membrane pNH3/pNH4+.

Adaptive changes to moderate seasonal heat in human subjects

1959 ◽  
Vol 14 (6) ◽  
pp. 995-996 ◽  
Author(s):  
Roy B. Mefferd
Keyword(s):  
Human Subjects ◽  
Economic Status ◽  
Urine Volume ◽  
South Texas ◽  
Moderate Increase ◽  
Waste Products ◽  
Average Temperature ◽  
Adaptive Mechanisms ◽  
Seasonal Heat ◽  
Excretion Rates

The excretion patterns of 29 members (including children) of 7 south Texas Caucasian families of varying economic status were determined each November (neutral-cool, averaging 68.7°F) and May (warm, averaging 81.6°F) for 3 consecutive years, to determine whether heat-adaptive mechanisms were stimulated by a moderate increase in average temperature as contrasted to intense heat. Four timed overnight samples from each person were analyzed in each period for five electrolytes, five nitrogenous waste products and thirteen amino acids. Excretion rates of most substances were lower in November than in May. Creatinine and the magnesium/calcium ratio were elevated, however, and the urine volume, magnesium, urea, glutamic acid, arginine and the sodium/potassium and uric acid/creatinine ratios did not change significantly. The excretion patterns of the heat-adapted human subjects were strikingly similar to those seen in heat-adapted rats. Submitted on April 13, 1959

scholarly journals Metabolic cold adaptation in fishes occurs at the level of whole animal, mitochondria and enzyme

2011 ◽  
Vol 279 (1734) ◽  
pp. 1740-1747 ◽  
Author(s):  
Craig R. White ◽  
Lesley A. Alton ◽  
Peter B. Frappell
Keyword(s):  
High Latitude ◽  
Cold Adaptation ◽  
Citrate Synthase ◽  
High Standard ◽  
Metabolic Rates ◽  
Thermal Plasticity ◽  
Metabolic Compensation ◽  
Low Latitudes ◽  
Effects Of Temperature ◽  
Metabolic Cold Adaptation

Metabolic cold adaptation (MCA), the hypothesis that species from cold climates have relatively higher metabolic rates than those from warm climates, was first proposed nearly 100 years ago and remains one of the most controversial hypotheses in physiological ecology. In the present study, we test the MCA hypothesis in fishes at the level of whole animal, mitochondria and enzyme. In support of the MCA hypothesis, we find that when normalized to a common temperature, species with ranges that extend to high latitude (cooler climates) have high aerobic enzyme (citrate synthase) activity, high rates of mitochondrial respiration and high standard metabolic rates. Metabolic compensation for the global temperature gradient is not complete however, so when measured at their habitat temperature species from high latitude have lower absolute rates of metabolism than species from low latitudes. Evolutionary adaptation and thermal plasticity are therefore insufficient to completely overcome the acute thermodynamic effects of temperature, at least in fishes.

Transcriptome of the Antarctic amphipod Gondogeneia antarctica and its response to pollutant exposure

2015 ◽  
Vol 24 ◽  
pp. 253-254 ◽  
Author(s):  
Seunghyun Kang ◽  
Sanghee Kim ◽  
Hyun Park
Keyword(s):  
Antarctic Amphipod ◽  
The Antarctic
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