Method for indirectly defining optimum temperatures of inhabitancy for marine cold-blooded animals

Investigations on the influence of pressure on the activity of alkaline phosphatase of some marine invertebrates from the Baltic Sea were carried out at temperatures between 5° and 55°C. The results obtained indicate that the influence of pressure on alkaline phosphatase activity is modified by temperature. At low temperatures, pressure has a decreasing effect on enzyme activity, while it has an increasing effect at higher temperatures. The gill homogenates of the relatively pressure-resistent bivalves Cyprina islandica and Mytilus edulis show a lower decrease of activity under pressure at low temperatures than the gill-homogenate of Carcinus maenas and a purified enzyme preparation of a homoiothermal animal.     

The effect of pressure on muscle lactate dehydrogenase activity of some deep-sea and shallow-water fishes

The activity of crude muscle lactate dehydrogenase (LDH) of several species of bathypelagic and shallow-water fishes has been measured at pressures between 1 and 578 atm and at temperatures of 15° and 25°C. No relationship has been found between the effect of pressure on enzyme activity and the hydrostatic pressure of the organism's environment. Applied hydrostatic pressure reduced activity at both temperatures. The decrease at 25°C was double the decrease at 15°C in LDH from shallow-water fishes. However, enzymes from 2 bathypelagic fishes showed approximately the same reduction at both temperatures. Thus, the interaction of temperature and pressure was less in deep-sea than in shallow-water fish LDH. Decreasing temperature and increasing pressure would both reduce the activity of LDH. That is, deep-sea conditions are noncompensatory in this instance. It is possible that the dissociation of the effects of temperature and pressure could be an adaptive feature of deep-sea life.This paper is a portion of a thesis submitted to the Graduate School, University of Georgia, in partial fulfillment for the degree of Master of Science.     

Larval viability and heterozygote deficiency in populations of marine bivalves: evidence from pair matings of mussels

Using a pressurized temperature gradient, which rapidly equilibrates bacteria to a wide range of temperature and pressures, temperature ranges for growth and survival of Vibrio harveyi (strain B 392) were found to narrow with increasing pressures. Both temperature and pressure ranges were greater in an enriched seawater medium than in unenriched seawater. Using a kinetics apparatus, V. harveyi was also exposed to gradual changes in temperature and pressure, simulating a particle sinking at approximately 200 m d^-1 from surface waters (17 °C; 1 bar pressure) to 3 400 m (4°C; 340 bars pressure). With gradual temperature changes, cells were able to grow and survive at lower temperatures than they had in rapid equilibration experiments. Gradual pressurization, however, did not increase pressure tolerance. Under all experimental conditions, the combined effects of low temperatures and high pressures were lethal for V. harveyi. It is hypothesized that temperature and pressure stratify the ocean into regions of growth, survival, and death for V. harveyi, and perhaps other bacteria.     

Molecular mechanisms of adaptation to low temperature in marine poikilotherms. Some regulatory properties of dehydrogenases from two arctic species

The properties of glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase from gill tissue of the tanner crab Chionocetes bairdi, and lactate dehydrogenase (LDH) and glyceraldehyde dehydrogenase from skeletal muscle of C. bairdi and the yellowfin sole Limanda aspera were examined over the physiological temperature range of the animals. Both animals were obtained in the Bering Sea in winter, and their enzymes appear to be remarkably cold-adapted. Affinity of sole LDH for substrate appears to increase with decreasing temperature, thus keeping reaction rate essentially independent of temperature at physiological concentrations of the substrate. Calculated values of activation energy are low, in keeping with the argument that organisms from cold environments have enzymes with a reduced energy of activation. In addition, Hill plots of the substrate saturation curves for lactate dehydrogenase from muscle of sole indicate that there is a facilitation of allosteric behaviour at low temperatures. Maximum affinity of sole LDH for substrate in the absence of univalent cations occurs at 3°C, while in the presence of 150 mN K⁺, it occurs between 0° to-2°C. The effects of Mg²⁺ on enzyme activity appear to be determined by concentration of substrate and temperature. Thus, glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase are stimulated more effectively by Mg²⁺ at low temperature and at low substrate levels whereas, at high concentrations of substrate, they are relatively independent of the bivalent cation. All four dehydrogenases are affected by the univalent cations Na⁺, K⁺ and NH₄ ⁺ in a manner which appears to be determined, in part at least, by concentration of substrate and by temperature. These findings suggest mechanisms for the maintenance and regulation of enzyme activity in poikilothermic tissues at low and changing temperatures.     

Über den einfluß des hydrostatischen druckes auf die ultrastrukturen von zellen und geweben. IV. Der effekt der temperatur auf die druckresistenz der membran-, filament- und mikrotubulisysteme verschiedener gewebe mariner muscheln und Branchiostoma lanceolatum

Temperature-pressure experiments have been carried out on gill epithelium of Modiolus modiolus and Mytilus edulis (Baltic and North Seas), as well as on the skin, pharynx, and trunk muscles of Branchiostoma lanceolatum (Pallas), employing the technique of pressure fixation. Temperatures of 0°, 5° and 15°C have been combined with pressures up to 800 atm. Low temperature (0°C) intensifies disintegration of ultrastructures by pressure in comparison to 5°C. The highest degree of structural disorganization can be observed at 600 atm and 0°C. Increased temperature (15°C) increases pressure resistance, but the structural difference is more quantitative than qualitative. In pressure experiments, temperature probably affects cell organelles at the molecular level.     

Aspects of the biology of resting spores of Thalassiosira nordenskioeldii and Detonula confervacea

Large numbers of resting spores of Thalassiosira nordenskioeldii Cleve and Detonula confervacea (Cleve) Gran were produced when these species were grown at low levels of ammonia and nitrate. The production of resting spores by T. nordenskioeldii was inversely related to temperature. At 0° and 5°C between 68 and 96% of the total cells were resting spores, while at 15°C resting spores were not produced. Resting spores of both species would not survive 7 days in the dark at 20°C. At 0°, 5°, 10° and 15°C, the length of time that the resting spores of both T. nordenskioeldii and D. confervacea remained viable was inversely related to temperature. At 0°C, T. nordenskioeldii remained viable for 576 days. The data suggest that the production of resting spores by these two species does not aid them in the survival of unfavorably high temperatures such as are found in temperate estuaries during the summer. Rather, they appear to be an adaptation for the survival of long periods of darkness in polar regions.     

A comparative study of metabolic energy expenditure in the limpets Patella cochlear,P. oculus and P. granularis

Oxygen consumption of 3 species of Patella was measured in air and water at various temperatures. Measurements at constant temperature over a full tidal cycle showed no tidal or light-dark rhythms. Measurements under conditions simulating natural tidal, temperature and day-night cycles allowed calculation of daily respiratory energy budgets. P. cochlear occurs low on the shore, but experiences a food shortage due to intense intraspecific competition. Its rate of respiration is moderate, but metabolic expenditure is kept low because exposure to air is brief and body temperatures seldom rise above 23°C. P. cochlear has a respiratory rate-temperature (R-T) curve which peaks at 20°C and forms a plateau between 20° and 32.5°C. The midshore P. oculus has abundant food and adopts an exploitative strategy. Growth rate is very high, and this high turnover of energy is linked with a high metabolic rate, high Q10 (temperature coefficient) values, high body temperatures during the day-time low tide, and a respiratory R-T curve peaking at 32.5°C. Small P. oculus occur mainly in intertidal pools and respire faster in water, while larger individuals occur on bare rocks and respire faster in air over the upper temperature range. In contrast, the upper-shore P. granularis has little food, and conservation of energy is essential, particularly as its growth rate is moderate and its reprocurve output high. Respiratory losses are reduced by suppression of the R-T curve and low Q10 values, resulting in relative independence of temperature. Small P. granularis occur low on the shore and respire slower in water. Larger individuals occur at high levels due to migration, and respire slower in air. This further reduces respiratory energy losses. The patterns of respiration in these 3 species are thus related to food availability, resulting in exploitative or conservationist strategies.     

Isolation and characterization of a marine bacteriophage

A bacteriophage active against a marine Aeromonas sp. was isolated from surface sediments of the North Pacific Ocean at 825 m depth. The sensitive Aeromonas sp. grew between 0° and 33°C but plaques were formed only between 0° and 23°C with a maximum zone of lysis at 5° to 12°C. The phage was rapidly inactivated at temperatures above 45°C. The characteristic plaque formation occurred only on media made with sea-water but some lysis was obtained in distilled water media supplemented with 0.085 M NaCl and 0.05 M MgCl₂. Phage replication occurred in cultures of Aeromonas sp. growing under applied hydrostatic pressures of up to 200 atmospheres. Electron microscopy revealed that the phage has an hexagonal head 530 Å in diameter, a thin tail 1200 Å in length and a terminal base plate 400 Å in diameter.     

Effect of temperature on specific dynamic action in the common octopus,<Emphasis Type="Italic"> Octopus vulgaris</Emphasis> (Cephalopoda)

Feeding causes an increase of metabolic rate, which initially escalates rapidly, reaches a peak value and then gradually declines to the pre-feeding rate. This phenomenon, termed specific dynamic action (SDA), reflects the energy requirements of the behavioral, physiological and biochemical processes that constitute feeding. The effect of temperature on SDA of the common octopus, Octopus vulgaris, was evaluated, by measuring the temporal pattern of the oxygen consumption rates of octopuses, after feeding, at two constant temperatures, 20°C and 28°C. At 20°C, the relative increase in the oxygen consumption rate after feeding (relative SDA) was significantly greater than at 28°C. The peak of the relative SDA occurred 1 h after feeding, and it was 64% at 20°C and 42% at 28°C. However, the SDA absolute peak, SDA duration (9.5 h) and SDA magnitude (the integrated postprandial increase in oxygen uptake) did not differ significantly between the two temperatures, indicating that the energetic cost of feeding was the same at both temperatures. The SDA response in O. vulgaris was much faster than it was in polar species, which have extended SDA responses due to low temperatures, and was also relatively fast in relation to the response in other temperate species, which is probably connected to the remarkably high growth rates of the species. A possible explanation of the observed summer migration of large octopuses from shallow to deeper areas is given, based on the effect of temperature on the energetic requirements of octopuses.     

Effects of various temperature cycles on the larval development of the gastropod molluscCrepidula fornicata

Veligers ofCrepidula fornicata (L.) were reared for 12 days at constant temperatures of 15°, 20°, 25°, 30° and 35°C, and at 5 C° daily cycles of equal periodicity (COEP) over the temperature ranges 15° to 20°C, 20° to 25°C, 25° to 30°C and 30° to 35°C. COEP consisted of equal periods (6 h) of maximum temperature, minimum temperature, and uniformly increasing and decreasing temperature each 24 h period. Survival was high and not influenced by cyclic or constant temperature from 15° to 30°C. At 35°C and COEP 30° to 35°C, all larvae died before Day 6. Shell growth rate increased markedly over the range 15° to 25°C, and growth rates at cyclic temperatures in this range were intermediate between growth rates at the corresponding constant temperatures. Larvae reared at COEP 15° to 20°C and COEP 30° to 35°C had discontinuities in their shells due to inhibition of shell secretion during the adverse part of each temperature cycle. Groups ofc. fornicata veligers were exposed for 2 days to daily temperature cycles of equal and unequal periodicity in the critical 30° to 35°C range. [Cycles of unequal periodicity (COUP) consisted of unequal periods (varying between 3 and 15 h) of maximum and minimum temperature and uniformly increasing and decreasing temperature each 24 h period.] These veligers showed shell growth although their body tissue declined, as indicated by decreasing carbon content per larva. Least shell growth and most body tissue loss occurred in those cycles with the longest exposure to higher temperature. Larvae exposed for arious days to the mildest 30° to 35°C COUP (15 h at 30°C, 3 h increasing temperature, 3 h at 35°C and 3 h decreasing temperature) recovered and resumed normal growth when transferred to constant 30°C, but their growth was retarded in proportion to the number of days in the temperature cycle. Rates of shell growth of veligers in temperature cycles show an immediate effect of environmental temperature, while changes in carbon content per larva better reflect the effects of temperature on general metabolism and survival.     

Incubation period for the lobster Homarus gammarus at various temperatures

For Homarus gammarus in the North Irish Sea, a notional spawning date of 15 August was selected on the basis of substantial commercial catch data. Berried females were exposed to fluctuating temperature regimes, with average temperatures between 10.0° and 18.3°C. Incubation periods ranged between 3.6 and 9.5 months. The relationship between incubation period and the sum of monthly average temperatures was approximately linear, and can be used to calculate the temperature regime required to cause hatching at a preselected time. At 10.4°C (the local annual average temperature), the estimated incubation period is 11 months. This is compared with data for H. americanus, which indicate an incubation period of 11.4 months at a local annual average temperature of about 8.1°C. The implications of this are discussed.     

Embryogenesis and larval biology of the ahermatypic scleractinian<Emphasis Type="Italic"> Oculina varicosa</Emphasis>

The ivory tree coral Oculina varicosa (Leseur, 1820) is an ahermatypic branching scleractinian that colonizes limestone ledges at depths of 6–100 m along the Atlantic coast of Florida. This paper describes the development of embryos and larvae from shallow-water O. varicosa, collected at 6–8 m depth in July 1999 off Fort Pierce, Florida (27°32.542 N; 79°58.732 W). The effect of temperature on embryogenesis, larval survival, and larval swimming speed were examined in the laboratory. Ontogenetic changes in geotaxis and phototaxis were also investigated. Embryos developed via spiral cleavage from small (100 µm), negatively buoyant eggs. Ciliated larvae developed after 6–9 h at 25°C. Embryogenesis ceased at 10°C, was inhibited at 17°C, and progressed normally at 25°C and 30°C. Larval survival, however, was high across the full range of experimental temperatures (11–31°C), although mortality increased in the warmest treatments (26°C and 31°C). Larval swimming speed was highest at 25°C, and lower at the temperature extremes (5°C and 35°C). An ontogenetic change in geotaxis was observed; newly ciliated larvae swam to the water surface and remained there for approximately 18 h, after which they swam briefly throughout the water column, then became demersal. Early larvae showed no response to light stimulation, but at 14 and 23 days larvae appeared to exhibit negatively phototactic behavior. Although low temperatures inhibited the development of O. varicosa embryos, the larvae survived temperature extremes for extended periods of time. Ontogenetic changes in larval behavior may ensure that competent larvae are close to the benthos to facilitate settlement. Previous experiments on survival, swimming speeds, and observations on behavior of O. varicosa larvae from deep-water adults indicate that there is no difference between larvae of the deep and shallow populations.Communicated by J.P. Grassle, New Brunswick     

A dispersal model for larvae of the deep sea red crab Geryon quinquedens based upon behavioral regulation of vertical migration in the hatching stage

Behavioral responses to gravity, hydrostatic pressure, and thermoclines are described for Stage I zoeae of the deep sea red crab Geryon quinquedens Smith. Survival and rate of development as a function of temperature is presented for all larval stages. Although temperatures between 10° and 25°C have no direct effect upon survival, development time is five times longer at 10°C than at 25°C. Stage I larvae show strong negative response to gravity. Swimming rate increases with an increase in pressure up to 20 atm above ambient at 11°C, but not at 15°C. Swimming rates at 15°C are higher than those measured at 11°C at each pressure tested. Stage I larvae readily penetrate sharp thermoclines. Potential dispersal ranges of G. quinquedens larvae in the Mid-Atlantic Bight are suggested based on larval behavior, development time, and coastal hydrography. A testable recruitment model is proposed for G. quinquedens.Contribution no. 1365 of the Center for Environmental and Estuarine Studies     

Temperature and development in larvae of the turbot Scophthalmus maximus

Turbot (Scophthalmus maximus L.) were reared at 12 and 16°C until 26 d after hatching. At both temperatures, starting at the neural plate stage, somites were initially formed every 75 min. Expressed as a percentage of development time (DT, fertilisation to 90% larvae hatching) somite formation occurred relatively earlier during embryogenesis at 12°C (45% DT) than at 16°C (55% DT). At 12°C, after the 32-somite stage the rate of somite formation decreased to one every 300 min. The larvae hatched after 6 d at 12°C and 3 d at 16°C at a relatively primitive stage of development, prior to the opening of the mouth and anus, with unpigmented eyes, and a straight gut. Temperature altered the relative timing of organogenesis in the larval stages. At 12°C, the following characters appeared (in this order): swimbladder>loop in the gut (at the time of yolk exhaustion)>caudal fin. In contrast, at 16°C, the caudal fin appeared at the same time as the loop in the gut. At 16°C, spines formed on the head in the region of the otic capsule at the time the swimbladder formed and the yolk was exhausted, but were absent in 12°C larvae. At both temperatures, in 1 d-old larvae the myotomes just behind the yolk-sac contained 200 inner muscle fibres (presumptive white muscle). The initial growth of inner muscle was largely due to hypertrophy, but by 26 d at 12°C and 11 d at 16°C hyperplastic growth became important, as evidenced by a significant increase in the number of small fibres (<10 m²). By 26 d the average number of inner muscle fibres had increased to 341 at 12°C and 988 at 16°C. New muscle fibres were added in distinct germinal zones at the dorsal and ventral apices of the myotomes. Metamorphosis was associated with a thickening of the superficial (presumptive red) muscle layer and the appearance of tonic muscle fibres.     

Comparative thermal metabolic patterns in Euterpina acutifrons dimorphic males

Thermal metabolic acclimation patterns have been determined for cold-and warm-acclimated dimorphic males of the copepod Euterpina acutifrons. The copepods were acclimated either to 15° or 25°C. Metabolic measurements were made at the two acclimation temperatures. At 25 °C, the small males had a higher rate than the large ones. At 15 °C, the large males had the higher rate. The metabolic pattern of thermal acclimation is also distinctive in the two forms. Small males showed metabolic adaptation at the lower acclimation temperature (15 °C), but not at the higher acclimation temperature (25 °C). In the large males the acclimation patterns were reversed, i. e., these males acclimated at the higher temperature, not at the lower. The acclimation patterns based on Precht's (1958) scheme of acclimation are entirely different in the two forms.Supported by PHS grant 5-SO5-FR-07070-02.     

Influence of sex and age on the feeding habits of the common soleSolea solea

The lethal concentration of cadmium was determined for the mysidLeptomysis lingvura G.O. Sars, a Mediterranean species from surface coastal waters, and the effect of sublethal doses on respiration, ammonia excretion, and feeding efficiency at different temperatures, and on activities of 19 hydrolases was tested. Experiments were carried out on individuals collected in spring 1987 near Marseille. At 18°C, respiration rate was significantly affected only by concentrations >0.05 mg Cd l^–1. At 0.1 mg Cd l^–1, respiration rate was more significantly depressed at 20°C than at 10°C. There was a concomitant decrease in the Q₁₀ rate (by 23 to 59%, according to the particular experiment), indicating a strong synergistic effect of temperature. Ammonia excretion was likewise affected by cadmium, also with a concomitant decrease in the Q₁₀ rate (by 34%). Daily faecal pellet production was maximum at 18°C; it was inhibited by cadmium at temperatures between 14 and 20°C, and enhanced at extreme temperatures (10 and 22°C). The assimilation efficiency of contaminated individuals was reduced by 9%. These decreases in faecal pellet production and assimilation efficiency reflect a significant decrease in energy (by about 43%) which could rapidly lead to an unbalanced energy budget with a consecutive lowering of the reproductive potential. Generally, hydrolase activities usually increased initially in the presence of 0.2 mg Cd l^–1, but after 48 h they declined, reaching very low values at 72 h. Most physiological processes are therefore affected by exposure to cadmium and the unbalanced energy budget arises from the inability to utilize environmental food. These results are consistent with the literature data on cadmium contamination in marine organisms. Physiological and biochemical changes appear to be very informative in studies of in vitro sublethal effects of micropollutants and in situ environmental modifications.     

Feeding,conversion efficiencies,and growth of larval mummichogs,Fundulus heteroclitus

Feeding rates, conversion efficiencies and growth of larvae of the mummichog Fundulus heteroclitus, an extremely abundant estuarine fish, were measured at temperatures ranging from 18° to 30°C. The food used was Artemia salina nauplii. At the time of total yolk sac absorption (5 to 7 days after hatching), the feeding rate decreased for a short time, an indication of a shift in metabolism. Higher feeding rates and growth occurred at higher rearing temperatures. The highest conversion efficiency (gross growth efficiency) was 1.1%, at 22°C. Mummichog larvae may be energetically inefficient compared with other fish species, but efficiency might not be critical for this fish, which is an opportunistic omnivore in an energy-rich environment.Contribution No. 291 of the Belle W. Baruch Institute for Marine Biology and Coastal Research, supported by DOE contract No. EY-76-5-09-0869.     

Autecological investigation on marine diatoms 3. Thalassiosira nordenskioeldii and Chaetoceros diadema

The temperature range for the best competitive position by growth of Thalassiosira nordenskioeldii Cleve has been determined by comparing generation times. It ranges from-1.5° to 6°C. At these temperatures, especially at lower light intensities, it was one of the fastest growing species, whereas above 6°C many other species grew faster. High light intensities at increasing temperatures became damaging. A flowering of the cold oligo-eurytherm diatom T. nordenskioeldii occurs not only in the upper layers, but can also occur at greater depth simultaneously, because decreasing daylengths at 6°C had the least influence on its growth. Continuous light at 6°C had a positive influence on its growth. The start of the T. nordenskioeldii spring flowering under the Arctic Sea Ice is discussed in connection with the occurrence of enclosed marine diatoms in Polar Sea Ice. The influence of the winter temperature on the spring flowering of the North Sea, the southern border for flowerings of T. nordenskioeldii, is discussed. For Chaetoceros diadema (Ehrenberg) Gran the best competitive position by growth is reached at-1.5° to about 6°C. It has the best opportunity of reaching high cell numbers at the lowest temperatures of the range. The occurrence of the cold oligo-eurytherm diatom Ch. diadema in plankton samples at temperatures above 10°C need not be incorret, for the species did grow in cultures at 12° and 16°C. The wrong interpretation of the experimentally determined optimum temperature of e.g. T. nordenskioeldii caused a discrepancy between experimental results and field data that does not exist. The question is discussed whether ecologically it is relevant to talk about a temperature optimum. On account of the results of T. nordenskioeldii the question of the adaptation of diatom cultures for the start of the real experiments is discussed.     

Comparative studies on the metabolism of shallow-water and deep-sea marine fishes. IV. Patterns of aerobic metabolism in the mesopelagic deep-sea fangtooth fish Anoplogaster cornuta

Measurements have been made of oxygen consumption rates O₂ of 10 specimens of the mesopelagic deep-sea fangtooth fish Anoplogaster cornuta. Determinations were made at 1 atm pressure, at temperatures of 3°, 7°, and 10°C, at dissolved oxygen concentrations ranging from near saturation to zero, with the fish swimming at low, controlled speeds. Weight-specific O₂ were uniformly low. They showed Q₁₀'s of 2.5 and 1.3, respectively, in the temperature ranges 3° to 7°C, and 7° to 10°C, at dissolved oxygen concentrations above 2 ml (standard temperature and presusure, STP)/1. Measurable O₂ continued in these fish at dissolved oxygen concentrations down to the lowest levels detectable with our instruments. At 7°C the average critical oxygen tension (P _c ) for the entire group was near 35 mm Hg. However, there is a statistically significant positive slope to the regression line relating O₂ to P _c for individual fish. The physiological and ecological significance of these results is discussed, particularly with reference to thermal effects and to the basis for survival by A. cornuta in the oxygen minimum layers of the eastern Pacific Ocean.     

Effect of temperature on nitrite excretion by three marine diatoms during nitrate uptake

Nitrite excretion during nitrate uptake by three nitrate-limited diatoms was measured at different temperatures. Phaeodactylum tricornutum Bohlin and Chaetoceros affinis Lauder Hustedt excreted nitrite over the whole range of physiological temperatures, whereas Thalassiosira pseudonana Hasle and Heimdal (Clone 13-1) excreted nitrite only at 25°C. Parallel to growth and nitrate-uptake rates, excretion rates increased exponentially with temperature, attaining a maximum between 20° and 25°C (optimum temperature range). At the end of nitrate uptake, when the nitrate concentration in the culture medium had decreased below 1 M, nitrite was reabsorbed at all temperatures, except when cells were in the dark or at very low light intensity. Nitrite uptake was also inhibited by the presence of nitrate in the medium. These results are discussed in relation to the formation and position of the maximum layer of primary nitrite in the thermocline, below the maximum layer of chlorophyll in stratified oceanic areas.