Effect of temperature and salinity on the oxygen consumption of laboratory produced Penaeus californiensis postlarvae

• 1.1. The oxygen consumption by P. californiensis postlarvae (mean wt = 0.38 g) was determined at five different temperatures and four salinities.
• 2.2. The O₂ in each chamber was recorded at 10 min intervals for 1 hr. The time course of oxygen depletion was independent of O₂ concentration down to 1.6 mg/l.
• 3.3. Oxygen consumption increased with temperature from 0.0045 mg/g/min at 19°C, to 0.0142 mg/g/min at 35°C. The thermal coefficient (Q₁₀) indicated a very high sensitivity of the postlarvae to temperature variations at 19–23°C.
• 4.4. The results show that oxygen consumption significantly depends on temperature (P < 0.001) while salinity has only a marginal effect.

     

Effects of salinity and temperature on oxygen consumption in a freshwater population of Palaemonetes antennarius (Crustacea,decapoda)

• 1.1. After step-like increases in salinity the shrimps exhibit the smallest increase in oxygen consumption in the lower salinity range. At higher salinities the shrimps show longer recovery times and greater increases in the metabolic rate after salinity shock.
• 2.2. In steady-state experiments, the shrimps display the lowest oxygen consumption rates near the isosmotic point. The lowest metabolic rates occur at salinities of 3‰ and 10‰ At salinities of 20‰ and above the rate of metabolism increases by 20–30%.
• 3.3. The calculated osmoregulatory work for animals in fresh water amounts to only 2.7% of routine metabolism and drops to 1.1% for shrimps in 3‰ and 0.7% in 5‰ salinity.
• 4.4. Locomotory activity in the form of position change was not responsible for the increased oxygen consumption of the animals after salinity shocks. A “tentative swimming activity” by fast and frequent beating of the pleopods without position change may be an important factor in the increase of metabolic rates.
• 5.5. In its temperature response, the brackish water population has a higher metabolic rate than the freshwater one. Between 5 and 35°C Q ₁₀-values range from 4.01 to 1.37.

     

Metabolic responses of the mussels Perna viridis and Perna indica to declining oxygen tension at different salinities

• 1.1. Oxygen uptake and ammonia loss were monitored during responses to reductions of both salinity and oxygen tension (PO₂) in the marine mussels Perna viridis and Perna indica from southern India.
• 2.2. The proportional contribution of protein to total catabolic substrates under natural environmental conditions was as much as 96% in P. viridis, relative to only 19% in P. indica.
• 3.3. Normoxic oxygen consumption remained statistically unchanged in P. viridis conditioned to salinities between 32 and 15‰, with no obvious signs of distress. Although equally unaffected at salinities between 32 and 20‰, P. indica showed significantly reduced oxygen uptake following transfer from 32 to 15‰, and had died within the next 7 days.
• 4.4. At salinities greater than 20‰, P. viridis was better able than P. indica to regulate oxygen consumption independent of PO₂.
• 5.5. P. indica showed a compensatory increase in oxyregulatory capacity at 15‰. This exceeded unstressed abilities, helping to maintain albeit reduced oxygen uptake throughout wider ranges of PO₂.
• 6.6. Different responses recorded in each of these tropical and often intertidal species were in accordance with their natural distributions. Nevertheless, the oxyregulatory capacity in both species was higher than in bivalves from temperate and/or subtidally restricted habitats.

     

Variations of respiratory rate of Tisbe holothuriae humes (copepoda,harpacticoida) in relation to temperature,salinity and food type

• 1.1. The influence of temperature (14,19, 24°C), salinity (26,32, 38,44%.) and food type (artificial diets: Fryfood, Mytilus, Soya, Yeast, Spirulina) on the respiratory rate of Tisbe holothuriae has been studied.
• 2.2. Oxygen consumption decreased with decreasing temperature, but with a greater rate at supra- or subnormal salinities.
• 3.3. Multiple-regression analysis showed the quadratic effect of temperature and the linear effect of salinity to be the more important factors affecting respiration.
• 4.4. The food type also seems to exert an important effect on oxygen consumption.
• 5.5. A significant lowering of respiration was observed for all food tested when the animals were starved.

     

Effect of size and temperature on the oxygen consumption of the brown shrimp Penaeus californiensis (Holmes, 1900)

• 1.1. The routine rate of oxygen consumption by Peneaus californiensis was determined for the size groups with average weights of 0.26, 2.31 and 10.01 g at five temperatures (19, 23, 27, 31 and 35°C).
• 2.2. Oxygen consumption (mg O₂/g min) was independent of dissolved oxygen (DO) level down to 1.8mg/l, increased with temperature (P < 0.05) from 0.0015mg O₂/g min for the preadults at 19°C to 0.0106 mg O₂/g min at 35°C for the postlarvae, and was inversely proportional to weight (P < 0.05).
• 3.3. The thermal coefficient (Q₁₀) indicated a higher sensitivity by preadults to temperature variations.

     

Cardiac frequency compensation responses of adult blue crabs (Callinectes sapidus Rathbun) exposed to moderate temperature increases

• 1.1. Cardiac frequency patterns of Callincctes sapidus Rathbun were used to evaluate potential thermal stress after exposure to 5°C increases over a range of acclimation temperatures from 5° to 30°C.
• 2.2. An acclimated rate-temperature curve (R-T curve), acute R-T curves of the stabilized rates at the increased temperatures and Q₁₀ temperature coefficients were used to assess the significance of the changes in rate frequency.
• 3.3. The acclimated R-T curve showed that blue crabs go through a series of seasonal adaptation types characterized by a plateau of perfect adaptation for both cold and warm adapted organisms. Paradoxical adaptation occurred between the transition from cold to warm acclimation temperatures.
• 4.4. The acute R-T curves showed that cardiac frequency was highly responsive to a 5°C increase when the organisms were acclimated to low temperatures.
• 5.5. The Q₁₀'s of the acute R-T curves at the warm acclimation temperatures approximated those values derived for the acclimated R-T curve.
• 6.6. This suggests that the temperature increase had a negligible effect on the warm adapted crabs, that is, little or no thermal stress occurred.

     

The effect of salinity and ion composition on oxygen consumption and nitrogen excretion of Macrobrachium rosenbergii (de man)

• 1.1. Oxygen consumption and nitrogen excretion rates of Macrobrachium rosenbergii were recorded in media of varying salinities and ion compositions (Mevo Hamma, Yahel, Elat—continental water; and 15 and 24%. seawater dilutions).
• 2.2. Oxygen consumption rates were not significantly different (P > 0.05) with the exclusion of Yahel having a metabolic rate of 0.258ml O₂/gfw/hr which was significantly different from the other experimental media at the P ≲- 0.05 level.
• 3.3. Nitrogen excretion rates were lowest in prawns adapted to Yahel water, 0.0188mg NH₄-N/gfw/hr and increased with salinity to 0.0494mg NH₄-N/gfw/hr in 24%.
• 4.4. The O: N ratios ranged from 12.24 to 22.65 indicating that in dilute media (Mevo Hamma and Yahel) relative to saline media (15%, Elat and 24%) more lipids and carbohydrates are utilized as an energy substrate while the latter group increased protein catabolism.

     

A comparative study of the respiratory properties and physiological function of haemocyanin in two burrowing and two non-burrowing crustaceans

• 1.1. Oxygen dissociation curves were constructed for the haemolymph of two non-burrowing, Galathea strigosa and Eupagurus bernhardus, and two burrowing crustaceans, C. cassivelaunus and Nephrops norvegicus. The p₅₀ at in vivo pH values and 10°C was 12.6 Torr in G. strigosa, 23 Torr in E. bernhardus, 3.1 Torr in C. cassivelaunus and 11.5 Torr in N. norvegicus.
• 2.2. The Bohr values (Δlogp₅₀/ΔpH) were high in all species ranging between −0.96 and −1.48. Cooperativity expressed as P₅₀ averaged 3.3, 3.8 and 3.8 in G. strigosa, E. bernhardus and N. norvegicus. respectively. A lower value of 2.2 was observed in C. cassivelaunus.
• 3.3. The oxygen affinity of the haemocyanin was relatively temperature independent, the values for ΔH at pH7.9 ranging between −5.1 and −18.1 kJmol⁻¹.
• 4.4. Haemolymph respiratory gas analysis showed values similar to those previously reported in crustaceans: p_aO₂ ranging between 44 and 107 Torr and p_vO₂ values between 18 and 24 Torr.
• 5.5. Pre-/post-branchial pH differences were small in G. strigosa, E. bernhardus and N. Norvegicus, but averaged 0.09 of a pH unit in C. cassivelaunus. p_aCO₂ and P_vCO₂ values ranged between 1.4 and 2.3 Torr.
• 6.6. In buried C. cassivelaunus both pre- and post-branchial oxygen tensions decreased, as did oxygen tension overall during respiratory pauses.
• 7.7. Cardiac output values were low, ranging between 59 and 71 ml kg⁻¹ min⁻¹ for all four species and calculated stroke volumes were realistic in terms of animal size.
• 8.8. In the non-burrowing species physically dissolved oxygen accounted for 5–21% of the oxygen transported to the tissues. In the burrowing species values of 40–77% were found.

     

The influences of individual variations in metabolic rate and tidal conditions on the response to hypoxia in Carcinus maenas (L.)

• 1.1. The oxygen consumption of crabs in normoxic and hypoxic (50% O₂) seawater was measured directly after collection.
• 2.2. The influences of size and lunar cycles were removed by scaling the data.
• 3.3. Strong negative correlations between low individual levels of O₂ consumption and the ability to compensate for hypoxia were apparent in Wicklow (subtidal) crabs.
• 4.4. Compensation for hypoxia was much greater on the flood tide than on the ebb.
• 5.5. Crabs from Roscoff (intertidal) had lower levels of compensation than those from Wicklow.
• 6.6. Size, sex and condition had no apparent effect upon these relationships.
• 7.7. Crabs acclimated to laboratory conditions have not shown this tidal variation in compensation for hypoxia.

     

The effect of salinity on coelomic fluid osmolyte concentration and intracellular water content in Luidia clathrata (Say) (Echinodermata: Asteroidea)

• 1.1. The concentrations (mM) of osmolytes in the coelomic fluid of Luidia clathrata kept at 25‰S seawater (control individuals) were: 345, Na⁺; 10, K⁺; 10, Ca²⁺; 44, Mg²⁺; 387, Cl⁻; 0.67, amino acids; 0.09, NH₄⁺.
• 2.2. When individuals were transferred from 25‰S to 15‰S or 35‰S, the concentrations of inorganic ions in the coelomic fluid usually equilibrated within 24hr and became the same as those in the medium.
• 3.3. The intracellular water content (g intracellular H₂O/g solute-free dry tissue) of the pyloric caeca and tube feet of control individuals throughout the experiment was 2.13 and 5.40, respectively.
• 4.4. In tissues of individuals transferred to 15‰S, the intracellular water content increased by an average 50% in 12 hr but returned to 19% above control levels during 1 week.
• 5.5. In tissues of individuals transferred to 35‰S, the intracellular water content decreased by an average 17% in 12 hr and did not change during 1 week.
• 6.6. Luidia clathrata is an osmoconformer and partial cell volume regulator within the seasonal salinity range it encounters.

     

The relationship between osmoregulation and nitrogen metabolism in the intertidal prawn,Palaemon elegans (Rathke)

• 1.1. The relationship between nitrogen metabolism and osmoregulation has been studied in the prawn Palaemon elegans (Rathke) following sudden exposure to hyper- and hyposaline conditions.
• 2.2. Animals acclimated to a salinity of 30‰ showed a pronounced increase in the rates of ammonia excretion during the first 2 hr after transfer to lower salinities. These gradually declined during the next 6 hr to rates that were significantly higher than that of control animals (30‰) and were maintained throughout the rest of the experiment.
• 3.3. Rates of ammonia excretion in animals transferred to hypersaline conditions (40‰) fluctuated considerably during the experiment. It was consistently observed, however, that there were two periods during the experiments when ammonia excretion rates had negative values indicating that NH⁺₄ ions were being taken up by the prawns.
• 4.4. Experiments in which small quantities of (NH₄)₂SO₄ containing the stable isotope ¹⁵N were added to the sea-water confirmed that P. elegans was able to take NH⁺₄ ions from the sea-water.
• 5.5. Changes in the Na⁺ ion concentration in the blood and the changes in free amino acid concentration in the blood and in the muscle after exposure to differing salinities were also determined. Their significance and relationship to the observed changes in the rates of ammonia excretion are discussed.

     

Metabolic rate and body temperature of adult and juvenile hyrax (Procavia capensis)

• 1.1. Resting metabolic rates (RMR) below thermoneutrality in adult hyrax acclimated to 26, 15 and 10°C remained unchanged, i.e. thermal conductance (K) remained constant.
• 2.2. Conductance in juveniles decreased with acclimation to lower ambient temperatures (T_a).
• 3.3. Body temperature (T_b) dropped by 3.8°C in adults exposed to T_a of 30 – 5°C. The decrease was constant.
• 4.4. Body temperature fell by 1.5°C in juveniles exposed to T_a of 30 – 20°C but stabilized between 20 and 5°C.
• 5.5. The labile T_b, associated with behavioural strategies and lower than predicted RMR, can be seen as an energy-conserving mechanism of particular importance during winter conditions.

     

Ventilation and blood acid-base balance of the crayfish as functions of water oxygenation (40–1500 Torr)

• 1.1. The specific ventilation, that is, the volume of water breathed to obtain a unit quantity of oxygen, was studied in 21 crayfish Astacus leptodactylus at partial pressures of O₂. PI_o2. between 40 and 1500 Torr.
• 2.2. The acid-base balance of the prebranchial hemolymph was studied in 17 other specimens between 43 and 575 Torr; the hemolymph pH was also measured at 1450 Torr in 11 other animals. Temperature of the water was controlled at 13°C, and its acid-base balance at a CO₂ pressure of 0.8 Torr and a pH of 8.40. The water was regularly renewed to avoid changes in ionic concentration.
• 3.3. The specific ventilation varied between 301.mmol⁻¹ in hypoxia (40 Torr) and 1 l·mmol⁻¹ in hyperoxia (1500 Torr). The actual ventilatory flow varied in about the same ratio since in this range of oxygenation the oxygen consumption is stable.
• 4.4. The values of pH and P_co2 of prebranchial hemolymph were respectively 7.99 and 1.3 Torr in hypoxia (PI_o2 = 43 Torr), 7.86 and 1.9 Torr in normoxia, and 7.73 and 4.7 Torr in hyperoxia (PI_o2 = 575 Torr). At PI_o2, = 1450 Torr. hemolymph pH was 7.60.
• 5.5. This study points up the tolerance of the crayfish to wide ranges of oxygen concentrations, the oxygen dependency of the ventilation which varied by a factor of 30 between 40 and 1500 Torr P_o2, and the oxygen dependency of the hemolymph acid-base balance, since pH varied 0.4 unit between hypoxia and hyperoxia.

     

Ionic regulation and salinity related changes in haemolymph protein in the semi-terrestrial beachflea Orchestia gammarellus (Pallas) (Crustacea: Amphipoda)

• 1.1. Orchestia gammarellus maintained in air and provided with food in the form of agar was found to be very tolerant of changes in the ionic content of the food and was shown to have well-developed powers of ionic regulation over the salinity range 5–40‰ at 10°C.
• 2.2. There was an inverse relationship between haemolymph protein and acclimation salinity.
• 3.3. The concentration of sodium and protein ions in the haemolymph of O. gammarellus from above high water mark (H.W.M.) was markedly different from animals collected below H.W.M. Individuals taken from above H.W.M. characteristically had low haemolymph sodium but elevated haemolymph protein concentrations.

     

Respiration and energetics in west indian gorgonacea (Anthozoa,octocorallia)

• 1.1. The rates of oxygen consumption of five species of Gorgonacea were determined and their daily energy requirements for metabolism were estimated.
• 2.2. Oxygen consumption rates varied between 0.15 and 0.76 mg O₂ g organic matter⁻¹ hr⁻¹.
• 3.3. Daily energy requirements varied between 13 and 66 cal g organic matter⁻¹ d⁻¹.
• 4.4. Energy costs for maintenance were somewhat lower than in other reef-dwelling Anthozoa.

     

Oxygen debt in reptiles: Relationship between the time required for repayment and metabolic rate

• 1.1. The increase in O₂ consumption in a 5 g lizard (Anolis carolinensis) after feeding and after maximal work was compared with that in a kilogram alligator (Alligator mississippiensis) treated similarly.
• 2.2. The amount of extra O₂ consumed/kg was the same in both. At the peak, there was a 2.6 fold increase in both animals following exhaustive work. Oxygen usage was elevated for 2 hr in the lizard and for 12 hr in the alligator, in inverse proportion to their respective metabolic rates.
• 3.3. Although the extra oxygen consumed was the same. feeding increased metabolic rate at the maximum by 300% in the alligator and by only 40% in the lizard.

     

Adaptative features of amazon fishes: Hemoglobins,hematology, intraerythrocytic phosphates and whole blood Bohr effect of Pterygoplichthys multiradiatus (Siluriformes)

• 1.1. Hemoglobin, hematological parameters, intraerythrocytic phosphates and whole blood Bohr effect of Pterygoplichthys multiradiatus, from the Amazon river, were studied in three different conditions: in their natural environment, acclimated to normoxia and acclimated hypoxia conditions.
• 2.2. Nine anodal hemoglobin fractions were detected on starch gel electrophoresis. No qualitative differences in the Hb electrophoretic patterns were detected in the three studied groups.
• 3.3. Hematocrit, hemoglobin concentration, MCV, MCHC and MCH were different among studied conditions.
• 4.4. GTP was almost absent in the blood of animals in natural conditions and acclimated to hypoxia, but was present at a concentration similar to ATP in normoxic acclimated animals.
• 5.5. There is a tendency for higher Hb-O₂ affinity for hypoxic acclimated/acclimatized animals.

     

Effect of temperature on oxygen consumption and heart rate of the australian crayfish Cherax tenuimanus (Smith)

• 1.1. Oxygen consumption at 18°C was 60% of the rate at 22 and 26°C.
• 2.2. Critical points, where the rate of oxygen consumption changed, were defined at 22°C (2.89 mg DO) and 26°C (3.46 mg DO). Linear regressions were fitted showing that oxygen consumption declined significantly (81.5% ±4.5) below the critical point.
• 3.3. Oxygen consumption was proportional to weight. Allometric relationships resulted in variable temperature-related coefficients for respiratory dependence on weight, a reflection of the crayfish adaptation towards re-establishment of a new equilibrium state.
• 4.4. Heart beat rate was lower at 18°C, and highest at the acclimation temperature (22°C). Stress at 26°C was evident.

     

Oxygen consumption and production by tropical ascidians symbiotic with Prochloron

• 1.1. Oxygen consumption and production rates were measured in two species of colonial ascidians that contained the algal symbiont, Prochloron.
• 2.2. Despite differences in size and habitats, the colonies showed similar rates of oxygen consumption and production.
• 3.3. Oxygen production by the colonies was light dependent.
• 4.4. Based on the data presented, the symbiosis is similar to other algal-invertebrate symbioses in producing more oxygen than is consumed when illuminated.

     

Metabolic responses of Cassin's Finches (Carpodacus cassinii) to temperature

• 1.1. The thermal neutral zone of Cassin's Finches extends from 22 to 37.5°C.
• 2.2. Standard metabolism (40.1 Wm⁻² or 7.6kcal bird⁻¹ day⁻¹) of the 28 g birds was 89% of the value predicted for passerines measured at night.
• 3.3. At temperatures below the zone of thermal neutrality metabolism is described by the relation, Wm⁻² = 1.55–74.5°C. The coefficient of heat transfer (1.55Wm⁻²°C⁻¹) is only 58% of the value predicted for birds of this size, indicating excellent insulation.
• 4.4. At temperatures above thermal neutralzfsity metabolism is described by the relation, Wm⁻² = 2.75–62.6°C.
• 5.5. Under conditions of heat stress (44.5°C; P_H2O = 8.6 Torr) Cassin's Finches were able to dissipate up to 208% of their metabolic heat production by evaporative water loss. Maximal rate of water loss was 56 mg g⁻¹ hr⁻¹.
• 6.6. At 20°C resting fasted finches lost a mean of 4.94 ± 1.5 SD mg H₂O g⁻¹hr⁻¹.