Patterns of temperature adaptation in North American Atlantic coastal actinians

Although acutely measured rate processes in coelenterates show close correlation with the Van't Hoff Q₁₀ rule and the distribution of many coelenterate groups is correlated with temperature, little is known about coelenterate temperature adaptation. Analysis of lethal temperatures shows that the southern distribution of 3 species of North Atlantic actinians is correlated with their upper lethal temperature. Oxygen consumption data from acute measurements indicate conformity to the Q₁₀ rule. Oxygen consumption data from animals pre-exposed to various temperatures indicate that oxygen consumption is capable of acclimation to temperature. Metridium senile from Massachusetts shows positive acclimation, typical of a poikilotherm partially regulating its metabolic rate in response to temperature change. Two species from Virginia, Haliplanella luciae and Diadumene leucolena, appear to show a reverse pattern. Their response includes encystment and negative adjustment of metabolic rate, showing evasion rather than regulation in response to environmental change. Temperature has a marked effect on parameters of the activity pattern of Diadumene leucolena, but the temperature sensitivity of activity is not correlated with that of oxygen consumption.     

Respiration and chemical composition of the bathypelagic euphausiid Bentheuphausia amblyops

Bentheuphausia amblyops is a cosmopolitan bathypelagic euphausiid with a vertical range of from 280 to 7 000 m. Determinations of proximate and elemental composition show that B. amblyops has a more robust structure (lower water content and higher protein content) than is typical of other bathypelagic Crustacea. B. amblyops is a strong swimmer and is capable of employing its thoracic legs in raptorial fashion. Discrete depth trawls taken between depths of 400 and 2 500 m on a diel basis show no evidence of vertical migration. There was no significant difference in oxygen consumption within the species environmental temperature range (1.5° to 7.5°C), which may be partially ascribed to a limited temperature effect and partially to variability in spontaneous activity at the different temperatures. Between 7.5° and 9.5°C there was a marked temperature effect on metabolism (Q₁₀=6.4). The observed vertical distribution and metabolic response to elevated temperature preclude the migrations to the surface that have been postulated for B. amblyops. The robust composition of the species, its behavioral characteristics, and published diet information strongly suggest that the species is omnivorous with a strong predatory component in its foraging strategy.     

Effects of temperature on activity,food consumption rates,and gut passage times of seaweed-eating<Emphasis Type="Italic"> Tegula</Emphasis> species (Trochidae) from California

Previous feeding studies on herbivorous marine snails rarely have focused on temperature effects on food intake. If temperature affects food intake, ectothermic snails may experience difficulty obtaining sufficient nutritional resources, limiting their ability to sustain populations at suboptimal temperatures. We hypothesized that the feeding responses of Tegula species would correspond with temperatures characteristic of their geographic distributions. We determined activity, consumption rates, and gut passage times at 11°C, 15°C, 19°C, and 23°C for three Tegula species with distinct thermal distributions: T. brunnea (cold water), T. aureotincta (warm water), and individuals from warm- and cold-water populations of T. funebralis, a broadly distributed species. Activity and consumption rates of T. aureotincta increased with increasing temperature, but were highest for T. brunnea at 19°C, a temperature rarely achieved in habitats occupied by this species, and lowest at 11°C. Warm-water T. funebralis showed significantly lower activity and consumption rates at 11°C, whereas cold-water T. funebralis consumed food fastest at 15°C and were most active at 23°C. Temperature affected gut passage time only in T. aureotincta. These data suggest that temperature might influence the northern limit of T. aureotincta by affecting activity and food consumption rates. T. brunneas activity and ability to consume food were not hindered by warmer temperatures despite the present day restriction of this species to colder waters. Also, widely separated (>300 km) T. funebralis populations may be adapted to regional conditions based on the different temperature responses of northern and southern snails.Communicated by P.W. Sammarco, Chauvin     

Metabolic rate and lipofuscin accumulation in juvenile European lobster (Homarus gammarus ) in relation to simulated seasonal changes in temperature

 The accumulation of lipofuscin, which is an indictor of physiological age, in the brain of juvenile European lobster (Homarus gammarus L.) was monitored for 22 mo in three experimental temperature regimes that simulated seasonal variation in temperature in the geographic range of this species. Metabolic rate responses to changes in temperature were estimated by measuring the activity of the electron transport system (ETS) in muscle tissue and in vivo rates of oxygen consumption. Lipofuscin accumulation oscillated with simulated seasonal changes in temperature and was described by seasonalised von Bertalanffy growth functions. The incremental accumulation in lipofuscin between sampling dates was linearly related to the number of degree days that accumulated between dates, irrespective of the amplitude of temperature fluctuation that had occurred. ETS activity increased with acclimation temperature and was modelled using a polynomial function. This indicated a lower temperature sensitivity in the temperature mid-range (12 to 16 °C), although the Q₁₀ for this mid-range was 2.1. ETS activity in lobsters acclimated to 8 and 18 °C and assayed at 13 °C was similar, indicating no compensation for changes in environmental temperature. Oxygen consumption rate was significantly higher at 14 °C than at 10.5 °C and had a Q₁₀ of 3.6, again suggesting no compensation to temperature change. The absence of metabolic compensation in response to temperature change in H. gammarus is consistent with the predictability of changes in temperature and food availability in the sub-littoral environment of this species. As lipofuscin accumulates according to metabolic rate, and metabolic rate in H. gammarus is directly correlated with temperature, geographic differences and long-term temporal trends in temperature will need to be considered when converting physiological age indices, obtained from lipofuscin estimates, to a chronological scale. Received: 27 April 2000 / Accepted: 21 July 2000     

The effect of temperature and thermal distribution on glycolysis in two rockfish species (Sebastes)

Studies on the effects of temperature on the activities of Embden-Meyerhof (EM) glycolysis, and the hexose monophosphate shunt (HMP) in fishes have dealt mainly with exotic and/or acclimated fishes. This study reports the effects of short-term reductions in temperature on EM and HMP activity in two closely related species of temperate fishes (Sebastes spp.) and its possible relation to the thermal distribution of the species. Thermal distribution data were collected by SCUBA for S. mystinus and S. serranoides in King Harbor, Redondo Beach, California, USA. Activities of the pathways were determined in liver-tissue studies, using glucose-¹⁴C and liquid scintillation techniques following the method of Hochachka (1968) with modifications. The data were analyzed by distribution-free methods. Tissue studies indicated HMP activity in both species at lowered temperature (5°C), but only in S. serranoides at 15°C. Results indicate that S. mystinus is capable of instantaneous temperature compensation, possibly related to its tendency to occupy cold waters.     

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.     

Interactive effects of pH,temperature and light during ammonia toxicity events in Elodea canadensis

Increased nutrient loading threatens many freshwater ecosystems. Elevated temperatures may increase the sensitivity to eutrophication in these ecosystems. Higher concentrations of possibly toxic reduced nitrogen (NH _x ) in the water layer may be expected as production and anaerobic breakdown rates will increase. Apart from temperature, NH _x and its effect on aquatic macrophytes will also depend on pH and light. We examined the interactive effects of NH _x , temperature, pH and light on Elodea canadensis in a full factorial laboratory experiment. Results demonstrate that high NH _x and high temperature together with low pH and low light causes the strongest toxic effects regarding relative growth rate and leaf tissue mortality. The adverse effects of high temperature and low light are most likely caused by increased metabolic activity and reduced photosynthesis, respectively. Severe toxicity at low pH compared to high pH can be ascribed to the ability of E. canadensis to induce a specialised bicarbonate-concentrating pathway at high pH, resulting in much higher carbon availability, needed for detoxification of NH _x . We conclude that NH _x toxicity will become more pronounced under higher temperatures, but that effects on aquatic macrophytes will strongly depend on pH of the water layer and specific metabolic adaptations of different species.     

Temperature and plankton

The relationship between temperature and metabolism was studied in Artic copepods with regard to the concept of metabolic cold adaptation of polar poikilotherms. Temperature tolerance and respiration rates of the dominant copepods Calanus finmarchicus (Gunnerus), C. glacialis (Jaschnov), C. hyperboreus (Krøyer) and Metridia longa (Lubbeck), collected in Fram Strait, Greenland Sea, in July 1983, were studied at different temperatures. Temperature tolerance in the boreal C. finmarchicus was slightly higher than in the three Arctic species. Respiration rates at lower temperatures followed the Arrhenius equation in all species, with values for (temperature characteristics) between 11.05 and 22.95, corresponding to a Q₁₀ between 2.05 and 4.5. This increase in metabolic rate with rising temperature was not related to an increase of swimming activity, as was shown by videoanalysis. Activity was determined as average swimming speed and as frequency of certain locomotor patterns. Average swimming speed remained unchanged at all temperatures and was ca 1 cm s^-1 for all species, when only periods of active swimming were considered. The time spent with active swimming did not change with temperature in M. longa and C. finmarchicus, but decreased in c. glacialis. In C. hyperboreus it increased at 5°C and decreased again at higher temperatures. It is suggested that the increase in oxygen consumption is fully accounted for by the basal metabolism.     

Metabolism,enzymic activities and cold adaptation in Antarctic mesopelagic fishes

Several species of Antarctic mesopelagic fishes that have different minimal depths of occurrence but the same environmental temperature were collected in November–December 1983 and in March 1986 between 0 and 1 000 m in the open water near the marginal ice zone in the vicinity of 60°S 40°W (1983) and 65°S 46°W (1986), and oxygen consumption rate (V _{O 2}) and the activity of two metabolic enzymes, lactate dehydrogenase (LDH, an indicator of the anaerobic potential of locomotory muscle) and citrate synthase (CS, an indicator of citric acid cycle activity or aerobic potential), were determined. In four dominant species, whole-individual oxygen-consumption rate (y, ml O₂ individual^–1 h^–1) varied with weight (X, g) according to the equation y=aX ^b, with b values falling between 0.889 and 1.029. The relation of weight-specific LDH activity (y, U g^–1 wet wt) with weight (x, g) was also described by the equation y=aX ^b, with b values varying between 0.229 and 1.025. Weight-specific CS activity declined with weight, with b values from-0.031 to-0.369. V _{2 O}, LDH activity and CS activity all declined markedly with increased species' minimum depth of occurrence (the depth below which 90% of a species' population lives). Comparisons with previous studies on ecologically equivalent species of the California Borderland indicate that depth-related decreases in metabolism are the result of adapted traits of deeper-living species, not declining temperature within the water column. The metabolic rate of Antarctic mesopelagic fishes is approximately twice that of California species at equivalent temperatures; similar rates were found at the normal habitat temperatures of the two groups. Thus, a well-developed compensation for temperature is present in the Antarctic fishes: cold adaptation. Differences in enzymic activity among species, and among different sized individuals of a species are related to differences in metabolic rate and locomotory capacity. Enzymic indices can be used to estimate metabolic rates and evaluate ecological parameters such as predatory strategies and niche separation.     

Temperature sensitivity of metabolism in offshore and intertidal onuphid polychaetes

Acclimated metabolism-temperature curves have been constructed for 4 populations of the intertidal onuphid Diopatra cuprea, and for the 2 offshore species Hyalinoecia tubicola and H. artifex. The intertidal species shows greater temperature sensitivity than its offshore relative, despite its presumed adaptation to thermally unstable habitats. Temperature changes considerably in excess of natural fluctuations do not greatly alter metabolic rates in Hyalinoecia. However, the range of thermal tolerance in these two species is considerably reduced.     

Upper temperature tolerances of some European molluscs

The upper temperature tolerances of three European species of Cardium [C. (Cerastoderma) glaucum Bruguière, C. tuberculatum L., C. (Cerastoderma) edule L.] are compared by means of median lethal temperature (LT₅₀) and median burial temperature (BT₅₀) determinations for periods of exposure up to 96 h. The influence of previous acclimation temperatures on these determinations is also considered. C. glaucum from shallow water (0.5 to 1 m), lagoonal, habitats in the Mediterranean Sea shows a greater thermal tolerance than C. tuberculatum from deeper water (4 to 5 m) in the Mediterranean. The thermal tolerance of C. edule from the intertidal zone, but at higher latitudes, is intermediate. Young C. glaucum show a greater resistance to short exposures to high temperatures than adults, but for longer exposures their tolerance is the same. All 3 species exhibit a significant effect of previous acclimation temperature on the burrowing response, and C. glaucum and C. tuberculatum a significant but lesser effect on LT₅₀. LT₅₀ determinations with C. edule showed secondary mortality effects which may have obscured any effect of acclimation temperature.     

Physioecology of zooplankton. I. Effects of phytoplankton concentration,temperature, and body size on the growth rate of Calanus pacificus and Pseudocalanus sp.

Changes in dry weight and in weight-specific growth rates were measured for copepodite stages of Calanus pacificus Brodsky and Pseudocalanus sp. cultured under various combinations of phytoplankton concentration and temperature. Mean dry weight of early copepodites was relatively unaffected by either food concentration or temperature, but mean dry weight of late stages increased hyperbolically with food concentration and was inversely related to temperature. The food concentration at which maximum body weight was attained increased with increasing temperature and body size, and it was considerably higher for C. pacificus than for Pseudocalanus sp. This suggests that final body size of small species of copepods may be determined primarily by temperature, whereas final body size of large species may be more dependent on food concentration than on temperature. Individual body weight increased sigmoidally with age. The weight-specific growth rate increased hyperbolically with food concentration. The maximum growth rate decreased logarithmically with a linear increase in body weight, and the slope of the lines was proportional to temperature. The critical food concentration for growth increased with body size proportionally more at high than at low temperature, and it was considerably higher for C. pacificus than for Pseudocalanus sp. Because of these interactions, early copepodites optimized growth at high temperature, even at low food concentrations, but under similar food conditions late stages attained higher growth at low temperature. The same growth patterns were found for both species, but the rates were significantly higher for the larger species, C. pacificus, than for the smaller one, Pseudocalanus sp. On the basis of findings in this study and of analyses of relationships between the maximum growth rate, body size, and temperature from other studies it is postulated (1) that the extrapolation of growth rates from one species to another on the basis of similarity in body size is not justified, even for taxonomically related species; (2) that the allometric model is inadequate for describing the relationship between the maximum weight-specific growth rate and body size at the intraspecific level; (3) that the body-size dependence of this rate is strongly influenced by temperature; and (4) that species of zooplankton seem to be geographically and vertically distributed, in relation to body size and food availability, to optimize growth rates at various stages of their life cycles.Contribution No. 1127 from the Department of Oceanography, University of Washington, Seattle, Washington 98195, USA     

Effects of emersion and temperature upon growth of the tropical brown alga Padina japonica,using a tide-simulation apparatus

A simple tide-simulation apparatus was used to investigate the influence of emersion and temperature on the intertidal growth of Padina japonica Yamada in both the juvenile and adult growth phases. The upper zonation limits are not determined by the sensitivity of any particular growth phase, since all phases show the same emersion tolerance limits. The species grows best when continuously submerged, and growth rates decrease with increasing emersion up to a clear upper zonation boundary. High temperature reduces the emersion tolerance and is therefore an important factor in tropical intertidal zonation.     

Physiological ecology of four Polysiphonia species (Rhodophyta,Ceramiales)

Photosynthesis and respiration of 4 species of the marine red algal genus Polysiphonia were evaluated under a variety of light, temperature and salinity conditions. The manometric results were compared with the local distribution and abundance of each species. The species can be separated into two distinct categories based on their overall distribution and temperature optima: (1) cold water plants [P. lanosa (L.) Tandy and P. elongata (Hudson) Sprengel], with peak photosynthesis at 21° to 24°C, but with active photosynthesis as low as 5°C; (2) plants with warm-water affinities [P. nigrescens (Hudson) Greville and P. subtilissima Montagne], having photosynthetic optima at 27° to 30°C, and exhibiting little or no photosynthesis below 10°C. The plants from the first group exhibit thermal injury at temperatures of 25°C and show a narrow tolerance to low salinities during periods of high temperatures. The plants from the second group show thermal injury at 30°C and have a wider tolerance to low salinities. The horizontal distribution of the 4 Polysiphonia species within the Great Bay Estuary System of New Hampshire, USA, is primarily governed by their tolerances to high temperatures and low salinities. The temperature optimum for each of the species corresponds to its particular estuarine distribution. Thus, P. subtilissima, having the highest temperature optimum, penetrated furthest into the Estuary, while P. lanosa, having the lowest temperature optimum, was restricted to the more coastal stations. There was a good correspondence between the natural distribution patterns and the manometric results.Published with the approval of the Director of the New Hampshire Agricultural Experiment Station as Scientific Contribution No. 731.Scientific Contribution No. 4 of the Jackson Estuarine Laboratory.     

Chemical mimicry of cuticular hydrocarbons – how does Eremostibes opacus gain access to breeding burrows of its host Parastizopus armaticeps (Coleoptera, Tenebrionidae)?

Summary. Breeding burrows of Parastizopus armaticeps armaticeps, a fossorial desert tenebrionid beetle, are cleptoparasitised by the closely related Eremostibes opacus. Gas chromatographic analyses show a high congruity of the cuticular hydrocarbons of both species. We compare these hydrocarbon patterns with those of four other Stizopina species and the Scaurini Herpiscius sommeri. In a bioassay, dummies treated with cuticular hydrocarbon extracts of E. opacus and the P. a. bifidus parasite E. bushmanicus were mostly ignored by P. a. armaticeps, whereas dummies with applied extracts of the remaining species were heavily attacked. We show that there is a correlation between agonistic behaviour of P. a. armaticeps towards the intruder and the chemical similarity of the cuticular hydrocarbons of the two species. Furthermore, we produced quantitatively modified hydrocarbon patterns of E. barbatus by changing the temperature at which this species was kept. The new 30 °C type was chemically similar to E. opacus, and was frequently ignored by P. a. armaticeps, whereas a reduction of the temperature to 20 °C only had minor effects on the hydrocarbon pattern. Furthermore, we show that the addition of one single component, heptacosane, to the cuticular hydrocarbon extract of E. opacus alters the host’s reaction. We discuss the role of cuticular hydrocarbons for the recognition of this host-parasite system and the relevance of quantitative characters in the hydrocarbon pattern for the discrimination of the host.     

Effects of temperature on yolk utilization,initial growth,and behaviour of unfed marine fish-larvae

The effect of temperature on yolk utilization, initial growth and behaviour of larvae of four species of marine fishes, i.e.,Acanthopagrus schlegeli, Engraulis japonica, Pagrus major andParalichthys olivaceus, was investigated under laboratory conditions at Hiroshima in 1989. The yolk sac was absorbed earlier with increasing temperature for all species. Morphological characters such as pectoral fin appearance, mouth opening and eye pigmentation differed from species to species over the range of experimental temperatures, and the sequence of development of these characters varied with temperature even within the same species. Temperature did not have a large influence on the maximum growth of unfed larvae, but had a clear effect on the time to starvation, occurring earlier at higher temperatures. Larval behaviour as indicated by time spent moving was also influenced by temperature; behavioural activity was greater at higher temperatures for all species examined. The effect of temperature on the early stage of larval life is discussed in terms of behavioural and morphological developments, as well as on yolk utilization, and its influence on larval survival in nature and under rearing conditions is evaluated.     

Comparative sensitivity of various developmental stages of sea urchins to some chemicals

The sensitivity to some chemical agents was examined comparatively at sperm, fertilization, cleavage, blastula, gastrula, pluteus and metamorphosis stages of a sand dollar from Japanese waters (Peronella japonica) and a sea urchin from the Pacific coast of Australia (Heliocidaris erythrogramma). These agents included Cu sulphate, ABS and NH₃ chloride. Responses observed included departures from control rates of fertilization and developmental reduction at the attainment of first cleavage, gastrula, pluteus or metamorphosis. Developmental anomalies were noted at the fertilization, 2-cell, gastrula, pluteus and metamorphosis stages. Using minimum effective concentrations of the 3 chemicals at various developmental stages of P. japonica, it was found that sensitivity to chemicals varies from fertilization to metamorphosis. It seems that sperm activity is the most sensitive, and that fertilization and gastrulation are more sensitive than first cleavage, blastulation and pluteus formation. H. erythrogramma seems to show nearly the same responses to Cu, but is more sensitive at metamorphosis.Experiments conducted at the Seto Marine Biological Laboratory, Wakayama Prefecture, JapanExperiments conducted at School of Biological Sciences, the University of Sydney, Sydney, N.S.W., AustraliaContributions from the Seto Marine Biological Laboratory, No. 664     

Antimutagenic and/or genotoxic effects of processed humic acids as tested upon S. cerevisiae D7

Humic acids (HAs) are formed during decomposition of organic matter. Their adsorption, dispersion or emulsification properties attract the interest of medical science and pharmacy. The aim of this work was to study antimutagenic effects of processed HA. Yeast strain Saccharomyces cerevisiae D7 was first used for HA antimutagenicity testing. The highest antimutagenic activity was found in potassium and sodium humates. Humates isolated from lignite pre-treated by HNO₃ exhibited slightly lower antimutagenic activity; this effect is caused probably by their higher oxidation degree. Sodium humate processed at 250°C exhibited genotoxic effect, which is probably connected with accelerated formation of reactive oxygen species such as superoxide anion by HA at higher temperature.     

Temperature tolerances of two southern African Ecklonia species (Alariaceae: Laminariales) and of hybrids between them

The temperature tolerances in culture of Ecklonia maxima (Osbeck) Papenf., the dominant kelp in the Benguela upwelling region on the west coast of southern Africa, and the smaller E. biruncinata (Bory) Papenf., growing on the warmer south coast, have been investigated. Vegetative growth and reproduction of gametophytes show very similar patterns in the two species, although temperature optima in E. biruncinata are consistently 2 ° to 3 °C higher than those of E. maxima. Reciprocal crosses between clonal female and male gametophytes of the two species produced healthy juvenile sporophytes, indistinguishable from the parent crosses. All parents and hybrids grew well over a wide range of temperatures (8 ° to 22°C), with E. biruncinata sporophytes again having slightly higher optima than E. maxima. Both reciprocal crosses exhibited optima intermediate between the parent crosses. The results are discussed with respect to the origins and evolution of Ecklonia species in the region.     

In situ pumping activities of tropical Demospongiae

Studies employing Scuba techniques were carried out on populations of 3 species of tropical demosponges to determine in situ patterns of water-pumping activity. Short-term changes in individual activity of deep-water species (15 to 55 m) were determined from continuous recordings of exhalant current velocities. Long-term changes were determined by repeated measurements of oscular velocity and oscular area. Mycale sp. was found to maintain constant levels of pumping activity in both short and long-term studies. Verongia gigantea underwent periodic cessations of activity averaging 42 min, at random intervals of approximately 19 h. Cessations were asynchronous throughout the population and inherent in origin. Long-term activity variations appeared to be cyclic, but were explainable by environmental events. Shallow-water populations of Tethya crypta exhibited a synchronized diurnal cycle of contraction and dilation, probably tied to the diurnal cycle of illumination. A longer term (average 15.8 days) cycle of activity-inactivity, also involving contraction and dilation, was asynchronous throughout the population during the calm season. Each individual maintained a fairly uniform cyclic period ranging from 9 to 21 days. Changes of T. crypta activity were probably due to changes in flagellar activity. With the onset of the stormy season, the activity of all members of the population was brought into synchrony by the effects of approximately biweekly storms. The behavior of Verongia archeri, Agelas sp., and other species indicates that constant activity (e.g. Mycale sp.) may be restricted to thin-walled species working at low pressures and velocities. Activity patterns are consistent within species, but variable in higher taxa. Behavioral activity patterns of sponges must be taken into account in ecological and physiological studies of these animals.