Differences In Temperature Tolerance Research Articles

Temperature Sensitivity of a Ciliated Protozoa (Family Paranophryidae) from American Lobster,Homarus americanus

Ciliated protozoan (family Paranophryidae) disease has been noted in American lobster, Homarus americanus, for twenty years. with annual outbreaks in impoundments since 1990. Mass mortalities and moribundity associated with this organism occur most frequently during periods when water temperatures are 2-3°C. Temperature sensitivity of this organism was evaluated in vitro. Results were compared to published data for lobsters to determine if interspecific differences in temperature tolerance could be exploited to control infections. Viability at human body temperature was also tested to determine if there was a health risk from eating infected (raw) lobster. Lethal temperature limit of this protozoan showed a time-temperature relationship: lowest temperature to show 100% mortality was 20°C; time to death was 150 minutes. The highest temperature tested was 37°C. At this temperature, mortality was 100% in one minute. The highest temperature tested which is tolerable to adult lobsters was 25°C. At that temperature, 100% mortality was achieved in 20 minutes.

Microcalorimetric Study on Myocardial Metabolism in a Hibernator and Two Nonhibernators at 20°C and 37°C

Metabolic activity in cardiac tissue slices from the guinea pig (GP), the rat (RT), the nonhibernating summer and winter hedgehog (SH and WH), respectively, was determined at 20° and at 37°C from their rates of heat production, P, (units, W/g tissue) by direct and indirect calorimetry. Energy-linked transport of Na + and K + in the tissues was determined from changes in metabolic rate induced by specific inhibition of the Na/K pump, the functional expression of Na/K-ATPase, the pacemaker enzyme in energy production assigned the role of transporting Na + and K + out of and into the cell. The results indicate a higher rate of energy production and utilization in the cardiac tissue of the hedgehog than in that of the nonhibernators, the rat and the guinea pig, at both temperatures. At 37°C the rate at which the cardiac tissue from the hedgehog consumed oxygen was as much as six times that registered for the guinea pig. The temperature coefficients of P and of the Na/K pump in the tissues from the two groups of hedgehogs were significantly higher than in the tissues from the rat and the guinea-pig ( P < 0.001). The determined metabolic indices, the basal rate of heat production P, the rate of oxygen consumption, P(O 2) in thermal units (W/g tissue), and the Na/K-pump capacity (PC) indicate species-specific differences between the animals. Both PC and its variation with temperature, ΔPC/Δ T°C, were in the order WH > SH > RT > GP. These results indicate that the hedgehog's cardiac tissue, in comparison with that of the nonhibernators, has a greater capacity to generate energy in general and for active transport of Na + and K + at 37°C after exposure to a lower temperature. A role is suggested for the Na/K-ATPase and some other unique rate-limiting enzymes in the metabolic pathway for the observed differences in temperature tolerance and cardiac performance between hibernators and nonhibernators.

Response of two species of amphibious stichaeoid fishes to temperature fluctuations in an intertidal habitat

The temperature regime of the intertidal microhabitat of two species of co-existing amphibious stichaeoid fishes, Anoplarchus purpurescens and Pholis ornata, were compared with experimentally determined tolerances to elevated temperatures. Studies of the critical thermal maxima of the two species revealed only slight differences in temperature tolerance but exposure to a cycled pattern of high temperatures sharply differentiated the resistance times of the two species with P. ornata capable of tolerating greater cumulative exposure to thermal stress when administered in a cycled program of temperature fluctuations with peak temperature at 27 °C. While the experimentally determined temperature tolerances exceeded those measured in the field, the greater tolerance of P. ornata may facilitate habitation of intertidal mudflats during summer months.

EFFECTS OF ELEVATED TEMPERATURE ON THE MORTALITY AND METABOLISM OF PACIFIC REEF CORALS

The upper thermal tolerance limits of subtropical (Hawaiian) and tropical (Enewetak) reef corals were determined both in the field and under laboratory conditions. Enewetak corals routinely withstand temperatures up to 34°C whereas similar exposure time at 32°C kill their Hawaiian congeners. These differing upper thermal limits correspond to increases of + 4 - 5°C above the annual water temperature maxima at each location. Reef coral temperature tolerance is therefore closely adapted to the ambient ocean temperature conditions of a geographic location.Studies of temperature effect on reef coral photosynthesis (P) and respiration (R) also showed different patterns between locations. Same species shower greater autotrophic capability at elevated temperatures in Enewetak than Hawaii. Critical temperatures estimated as coinciding with P:R ratio values minimal to support long term functional autotrophy were 2-5°C higher for Enewetak than Hawaiian specimens, closely corresponding to observed differences in upper thermal tolerance. Results support a hypothesis of temperature adaptation capability for reef corals and suggest that short term physiological tests can predict relative differences in temperature tolerance among coral species.

Temperature tolerance of the polychaete worms Diopatra cuprea and Clymenella torquata

The resistance to high temperatures of two species of intertidal tube-dwelling polychaete worms has been tested to show seasonal and geographic variations. The summer 50% survival temperature at Beaufort, North Carolina, was 42.5 °C for Diopatra cuprea (Bosc) and 40.5 °C for Clymenella torquata (Leidy). Winter 50% survival temperatures for both species at Beaufort were approximately 4.0 C° lower. Both species showed a geographic difference in 50% survival temperature of more than 4.0 C° between North Carolina and Massachusetts in summer. D. cuprea from the Mississippi coast showed a lower survival temperature, probably due to combined temperature and salinity effects. Laboratory acclimation of C. torquata from Beaufort at low temperatures, during summer months, produced experimental results similar to those from winter animals. The seasonal differences in temperature tolerance are phenotypic expressions of a physiological response which can be related to environmental temperature patterns.

On the behaviour of barnacles. IV: The influence of temperature On cirral activity and survival of some warm-water species

SUMMARYThe range of temperatures over which the cirri were active and the frequency of beating at different temperatures were measured in four species of barnacles collected on the southern and south-western coasts of France. The extremes of high temperature at which the animal remained irritable or could survive were assessed in these species and in a further group of species from Trinidad, West Indies.The results are discussed in comparison with previous evidence for species of more northern distribution, and related to the geographical range of the species and the ecological niche occupied. For example, the brackish water species, Balanus eburneus and B. improvisus, have similar patterns of cirral activity, but the greater tolerance of high temperatures shown by the former is obviously connected with its more tropical distribution. Differences in temperature tolerances of varieties of JB. amphitrite from Europe and Trinidad, possibly related to differences in the tide levels at which they live, tend to reinforce their separation on morphological grounds. More pronounced differences between Chthamalus depressus and C. stellatus confirm the separation of these two species which were formerly regarded as varieties. The relatively lower rate of beating of C. depressus which is not found north of the Mediterranean and its greater tolerance of high temperatures compared with C. stellatus, may be related to its more southern distribution and its ability to live at very high levels on the shore. These two species and C. fragilis from Trinidad all show greater tolerance of high temperatures than the species of Balanus and Tetraclita, which are found at lower levels on the shoreIt is concluded that in the North Atlantic area there may be only two main distributional groups of species of acorn barnacles, Arctic and Tropical, overlapping in the Temperate regions, with few or no intermediate forms, and that there is as yet no evidence for the existence of physiological races in these species.